Downhole vibration sensing by vibration energy harvesting
Trimble, A. Zachary
2007-01-01
This thesis outlines the design of a prototype electromagnetic induction vibration energy harvesting device for use in a downhole environment. First order models of the necessary components for a generic vibration energy ...
Piezoelectric cantilevers optimization for vibration energy harvesting
NASA Astrophysics Data System (ADS)
Cao, Junyi; Zhou, Shengxi; Ren, Xiaolong; Cao, Binggang
2012-04-01
Vibration-based piezoelectric energy harvesters through the conversion of vibration energy to electrical energy has gained increasing attention over the past decade because of the reduced power requirements of small electronic components, especially in industrial condition monitoring applications where sensors may be embedded in machines. The structure parameters of cantilevered piezoelectric energy harvesters are of importance to maximize the output power in accordance with the characteristics of the ambient vibrations. Therefore, a piezoelectric cantilevers optimization method using finite element analysis and SPICE is proposed. This paper models piezoelectric cantilever using Hamilton principle and extracts the vibration modal parameters to establish the circuit model in SPICE. The numerical analysis is addressed to study the effect of parameters. Finally, the optimization analysis and experiment are carried out. The results verify that the optimized cantilevered piezoelectric energy harvesters can produce a 56V peak open-circuit voltage, and that the proposed method is suitable for optimization design of piezoelectric energy harvester.
Piezoelectric cantilevers optimization for vibration energy harvesting
NASA Astrophysics Data System (ADS)
Cao, Junyi; Zhou, Shengxi; Ren, Xiaolong; Cao, Binggang
2011-11-01
Vibration-based piezoelectric energy harvesters through the conversion of vibration energy to electrical energy has gained increasing attention over the past decade because of the reduced power requirements of small electronic components, especially in industrial condition monitoring applications where sensors may be embedded in machines. The structure parameters of cantilevered piezoelectric energy harvesters are of importance to maximize the output power in accordance with the characteristics of the ambient vibrations. Therefore, a piezoelectric cantilevers optimization method using finite element analysis and SPICE is proposed. This paper models piezoelectric cantilever using Hamilton principle and extracts the vibration modal parameters to establish the circuit model in SPICE. The numerical analysis is addressed to study the effect of parameters. Finally, the optimization analysis and experiment are carried out. The results verify that the optimized cantilevered piezoelectric energy harvesters can produce a 56V peak open-circuit voltage, and that the proposed method is suitable for optimization design of piezoelectric energy harvester.
Vibration energy harvesting: fabrication, miniaturisation and applications
NASA Astrophysics Data System (ADS)
Beeby, S. P.; Zhu, D.
2015-05-01
This paper reviews work at the University of Southampton and its spin-out company Perpetuum towards the use of vibration energy harvesting in real applications. Perpetuum have successfully demonstrated vibration-powered condition monitoring systems for rail and industrial applications. They have pursued applications were volume is not a particular constraint and therefore sufficient power can be harvested. Harvester reliability and longevity is a key requirement and this can be a challenging task in high shock environments. The University of Southampton has investigated the miniaturization of the technology. MEMS electromagnetic harvesters were found to be unsuitable although miniaturized devices fabricated using bulk components did perform well. Screen printed piezoelectric harvesters were also found to perform well and were ideally suited to a low profile application where device thickness was limited. Screen printing was not only used to deposit the active piezoelectric material but also an inertial mass ink based on tungsten. This enables the device to be printed entirely by screen printing providing a low-cost route to manufacture. Finally, details of a simulation tool that can take real world vibrations and estimate vibration energy harvester output was presented. This was used to simulate linear and nonlinear harvesters and in many applications with a characteristic resonant frequency the linear approach was found to be the optimum. Bistable nonlinear harvesters were found to work better with more random vibration sources.
Harvesting Vibrational Energy Using Material Work Functions
Varpula, Aapo; Laakso, Sampo J.; Havia, Tahvo; Kyynäräinen, Jukka; Prunnila, Mika
2014-01-01
Vibration energy harvesters scavenge energy from mechanical vibrations to energise low power electronic devices. In this work, we report on vibration energy harvesting scheme based on the charging phenomenon occurring naturally between two bodies with different work functions. Such work function energy harvester (WFEH) is similar to electrostatic energy harvester with the fundamental distinction that neither external power supplies nor electrets are needed. A theoretical model and description of different operation modes of WFEHs are presented. The WFEH concept is tested with macroscopic experiments, which agree well with the model. The feasibility of miniaturizing WFEHs is shown by simulating a realistic MEMS device. The WFEH can be operated as a charge pump that pushes charge and energy into an energy storage element. We show that such an operation mode is highly desirable for applications and that it can be realised with either a charge shuttle or with switches. The WFEH is shown to give equal or better output power in comparison to traditional electrostatic harvesters. Our findings indicate that WFEH has great potential in energy harvesting applications. PMID:25348004
Energy harvesting from an autoparametric vibration absorber
NASA Astrophysics Data System (ADS)
Yan, Zhimiao; Hajj, Muhammad R.
2015-11-01
The combined control and energy harvesting characteristics of an autoparametric vibration absorber consisting of a base structure subjected to the external force and a cantilever beam with a tip mass are investigated. The piezoelectric sheets are attached to the cantilever beam to convert the vibrations of the base structure into electrical energy. The coupled nonlinear representative model is developed by using the extended Hamiton’s principle. The effects of the electrical load resistance on the frequency and damping ratio of the cantilever beam are analyzed. The impacts of the external force and load resistance on the structural displacements of the base structure and the beam and on the level of harvested energy are determined. The results show that the initial conditions have a significant impact on the system’s response. The relatively high level of energy harvesting is not necessarily accompanied with the minimum displacements of the base structure.
Internal resonance for nonlinear vibration energy harvesting
NASA Astrophysics Data System (ADS)
Cao, D. X.; Leadenham, S.; Erturk, A.
2015-11-01
The transformation of waste vibration energy into low-power electricity has been heavily researched over the last decade to enable self-sustained wireless electronic components. Monostable and bistable nonlinear oscillators have been explored by several research groups in an effort to enhance the frequency bandwidth of operation. Linear two-degree-of-freedom (2-DOF) configurations as well as the combination of a nonlinear single-DOF harvester with a linear oscillator to constitute a nonlinear 2-DOF harvester have also been explored to develop broadband energy harvesters. In the present work, the concept of nonlinear internal resonance in a continuous frame structure is explored for broadband energy harvesting. The L-shaped beam-mass structure with quadratic nonlinearity was formerly studied in the nonlinear dynamics literature to demonstrate modal energy exchange and the saturation phenomenon when carefully tuned for two-to-one internal resonance. In the current effort, piezoelectric coupling and an electrical load are introduced, and electromechanical equations of the L-shaped energy harvester are employed to explore primary resonance behaviors around the first and the second linear natural frequencies for bandwidth enhancement. Simulations using approximate analytical frequency response equations as well as numerical solutions reveal significant bandwidth enhancement as compared to a typical linear 2-DOF counterpart. Vibration and voltage responses are explored, and the effects of various system parameters on the overall dynamics of the internal resonance-based energy harvesting system are reported.
Enhanced vibration energy harvesting using nonlinear oscillations
NASA Astrophysics Data System (ADS)
Engel, Emily; Wei, Jiaying; Lee, Christopher L.
2015-05-01
Results for the design and testing of an electromagnetic device that converts ambient mechanical vibration into electricity are presented. The design of the device is based on an L-shaped beam structure which is tuned so that the first two natural frequencies have a near two-to-one ratio which is referred to as an internal resonance or autoparametic condition. It is shown that in contrast to single degree-of-freedom, linear-dynamics-based vibration harvesters which convert energy in a very narrow frequency band the prototype can generate power over an extended frequency range when subject to harmonic, base displacement excitation.
Vibration energy harvesting for unmanned aerial vehicles
NASA Astrophysics Data System (ADS)
Anton, Steven R.; Inman, Daniel J.
2008-03-01
Unmanned aerial vehicles (UAVs) are a critical component of many military operations. Over the last few decades, the evolution of UAVs has given rise to increasingly smaller aircraft. Along with the development of smaller UAVs, termed mini UAVs, has come issues involving the endurance of the aircraft. Endurance in mini UAVs is problematic because of the limited size of the fuel systems that can be incorporated into the aircraft. A large portion of the total mass of many electric powered mini UAVs, for example, is the rechargeable battery power source. Energy harvesting is an attractive technology for mini UAVs because it offers the potential to increase their endurance without adding significant mass or the need to increase the size of the fuel system. This paper investigates the possibility of harvesting vibration and solar energy in a mini UAV. Experimentation has been carried out on a remote controlled (RC) glider aircraft with a 1.8 m wing span. This aircraft was chosen to replicate the current electric mini UAVs used by the military today. The RC glider was modified to include two piezoelectric patches placed at the roots of the wings and a cantilevered piezoelectric beam installed in the fuselage to harvest energy from wing vibrations and rigid body motions of the aircraft, as well as two thin film photovoltaic panels attached to the top of the wings to harvest energy from sunlight. Flight testing has been performed and the power output of the piezoelectric and photovoltaic devices has been examined.
Summer Internship Report: Vibration Energy Harvesting using PEH25W
Summer Internship Report: Vibration Energy Harvesting using PEH25W Peter Sam Raj May - July 2011.1 Commercially available Vibration Energy Harvesters . . . . . . . 8 3.1.1 PMG FSH by Perpetuum . . . . . . . . . . . . . . . . . . 25 5.4 Parking Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 5.5 Vibration
Energy harvesting from wind-induced vibration of suspension bridges
Shi, Miao, M. Eng. Massachusetts Institute of Technology
2013-01-01
Recently, an extensive amount of research has been focused on energy harvesting from structural vibration sources for wireless self-powered microsystem applications. One method of energy harvesting is using electromagnetic ...
Adjustable Nonlinear Springs to Improve Efficiency of Vibration Energy Harvesters
S. Boisseau; G. Despesse; B. Ahmed Seddik
2015-06-01
Vibration Energy Harvesting is an emerging technology aimed at turning mechanical energy from vibrations into electricity to power microsystems of the future. Most of present vibration energy harvesters are based on a mass spring structure introducing a resonance phenomenon that allows to increase the output power compared to non-resonant systems, but limits the working frequency bandwidth. Therefore, they are not able to harvest energy when ambient vibrations' frequencies shift. To follow shifts of ambient vibration frequencies and to increase the frequency band where energy can be harvested, one solution consists in using nonlinear springs. We present in this paper a model of adjustable nonlinear springs (H-shaped springs) and their benefits to improve velocity-damped vibration energy harvesters' (VEH) output powers. A simulation on a real vibration source proves that the output power can be higher in nonlinear devices compared to linear systems (up to +48%).
Nonlinear spring-less electromagnetic vibration energy harvesting system
NASA Astrophysics Data System (ADS)
Hadas, Z.; Ondrusek, C.
2015-11-01
This paper deals with a description and modelling of a spring-less electromagnetic vibration energy harvesting system. The presented unique electromagnetic vibration energy harvester consists of a nonlinear resonance mechanism, magnetic circuit with a coil and an electronic load. The mechanical vibrations excite the nonlinear resonance mechanism and the relative movement of the magnetic circuit against fixed coil induces voltage due to Faraday's Law. When the electronics is connected the current flows through the load and output power is harvested. There are several nonlinearities which affects operations of the presented electromagnetic energy harvesting system. The significant nonlinearity of the system is stiffness of the resonance mechanism and it causes extending of an operation bandwidth. The harvesting of electrical energy from mechanical vibrations provides electromagnetic damping feedbacks of the coil to moving magnetic circuit. The feedback depends on the current flow through the electronic load and coil. The using of modern power management circuit with optimal power point provides other nonlinear operation.
A MEMS vibration energy harvester for automotive applications
NASA Astrophysics Data System (ADS)
van Schaijk, R.; Elfrink, R.; Oudenhoven, J.; Pop, V.; Wang, Z.; Renaud, M.
2013-05-01
The objective of this work is to develop MEMS vibration energy harvesters for tire pressure monitoring systems (TPMS), they can be located on the rim or on the inner-liner of the car tire. Nowadays TPMS modules are powered by batteries with a limited lifetime. A large effort is ongoing to replace batteries with small and long lasting power sources like energy harvesters [1]. The operation principle of vibration harvesters is mechanical resonance of a seismic mass, where mechanical energy is converted into electrical energy. In general, vibration energy harvesters are of specific interest for machine environments where random noise or repetitive shock vibrations are present. In this work we present the results for MEMS based vibration energy harvesting for applying on the rim or inner-liner. The vibrations on the rim correspond to random noise. A vibration energy harvester can be described as an under damped mass-spring system acting like a mechanical band-pass filter, and will resonate at its natural frequency [2]. At 0.01 g2/Hz noise amplitude the average power can reach the level that is required to power a simple wireless sensor node, approximately 10 ?W [3]. The dominant vibrations on the inner-liner consist mainly of repetitive high amplitude shocks. With a shock, the seismic mass is displaced, after which the mass will "ring-down" at its natural resonance frequency. During the ring-down period, part of the mechanical energy is harvested. On the inner-liner of the tire repetitive (one per rotation) high amplitude (few hundred g) shocks occur. The harvester enables an average power of a few tens of ?W [4], sufficient to power a more sophisticated wireless sensor node that can measure additional tire-parameters besides pressure. In this work we characterized MEMS vibration energy harvesters for noise and shock excitation. We validated their potential for TPMS modules by measurements and simulation.
Ribeiro, Roland
2014-10-23
harvesters. Most of this has however been limited to harvesters with single vibration sources or multiple sources vibrating synchronously. This work presents a multiple input piezoelectric energy harvester capable of harvesting from multiple piezoelectric...
Trimble, A. Zachary
2011-01-01
In general, vibration energy harvesting is the scavenging of ambient vibration by transduction of mechanical kinetic energy into electrical energy. Many mechanical or electro-mechanical systems produce mechanical vibrations. ...
The bandwidth of optimized nonlinear vibration-based energy harvesters
NASA Astrophysics Data System (ADS)
Cammarano, A.; Neild, S. A.; Burrow, S. G.; Inman, D. J.
2014-05-01
In an attempt to improve the performance of vibration-based energy harvesters, many authors suggest that nonlinearities can be exploited to increase the bandwidths of linear devices. Nevertheless, the complex dependence of the response upon the input excitation has made a realistic comparison of linear harvesters with nonlinear energy harvesters challenging. In a previous work it has been demonstrated that for a given frequency of excitation, it is possible to achieve the same maximum power for a nonlinear harvester as that for a linear harvester, provided that the resistance and the linear stiffness of both are optimized. This work focuses on the bandwidths of linear and nonlinear harvesters and shows which device is more suitable for harvesting energy from vibrations. The work considers different levels of excitation as well as different frequencies of excitation. In addition, the effect of the mechanical damping of the oscillator on the power bandwidth is shown for both the linear and nonlinear cases.
Modeling and design of a MEMS piezoelectric vibration energy harvester
Du Toit, Noël Eduard
2005-01-01
The modeling and design of MEMS-scale piezoelectric-based vibration energy harvesters (MPVEH) are presented. The work is motivated by the need for pervasive and limitless power for wireless sensor nodes that have application ...
Magnetic induction systems to harvest energy from mechanical vibrations
Jonnalagadda, Aparna S
2007-01-01
This thesis documents the design process for magnetic induction systems to harvest energy from mechanical vibrations. Two styles of magnetic induction systems - magnet-through-coil and magnet-across-coils - were analyzed. ...
Wideband electromagnetic energy harvesting from ambient vibrations
NASA Astrophysics Data System (ADS)
Mallick, Dhiman; Podder, Pranay; Roy, Saibal
2015-06-01
Different bandwidth widening schemes of electromagnetic energy harvesters have been reported in this work. The devices are fabricated on FR4 substrate using laser micromachining techniques. The linear device operate in a narrow band around the resonance; in order to tune resonant frequency of the device electrically, two different types of complex load topologies are adopted. Using capacitive load, the resonant frequency is tuned in the low frequency direction whereas using inductive load, the resonant frequency is tuned in the high frequency direction. An overall tuning range of ˜2.4 Hz is obtained at 0.3g though the output power dropped significantly over the tuning range. In order to improve the off-resonance performance, nonlinear oscillation based systems are adopted. A specially designed spring arm with fixed-guided configuration produced single well nonlinear monostable configuration. With increasing input acceleration, wider bandwidth is obtained with such a system as large displacement, stretching nonlinearity comes into play and 9.55 Hz bandwidth is obtained at 0.5g. The repulsive force between one static and one vibrating oppositely polarized magnets are used to generate bistable nonlinear potential system. The distance between the mentioned magnets is varied between 4 to 10 mm to produce tunable nonlinearity with a maximum half power bandwidth over 3 Hz at 0.5g.
Energy harvesting using vortex-induced vibrations of tensioned cables
Grouthier, Clement; de Langre, Emmanuel
2012-01-01
The development of energy harvesting systems based on fluid/structure interactions is part of the global search for innovative tools to produce renewable energy. In this paper, the possibility to harvest energy from a flow using vortex-induced vibrations (VIV) of a tensioned flexible cable is analyzed. The fluid loading on the vibrating solid and resulting dynamics are computed using an appropriate wake-oscillator model, allowing one to perform a systematic parametric study of the efficiency. The generic case of an elastically-mounted rigid cylinder is first investigated, before considering an infinite cable with two different types of energy harvesting : a uniformly spanwise distributed harvesting and then a periodic distribution of discrete harvesting devices. The maximum harvesting efficiency is of the same order for each configuration and is always reached when the solid body and its wake are in a frequency lock-in state.
Piezoelectric diaphragm for vibration energy harvesting.
Minazara, E; Vasic, D; Costa, F; Poulin, G
2006-12-22
This paper presents a technique of electric energy generation using a mechanically excited unimorph piezoelectric membrane transducer. The electrical characteristics of the piezoelectric power generator are investigated under dynamic conditions. The electromechanical model of the generator is presented and used to predict its electrical performances. The experiments was performed with a piezoelectric actuator (shaker) moving a macroscopic 25 mm diameter piezoelectric membrane. A power of 0.65 mW was generated at the resonance frequency (1.71 kHz) across a 5.6 kOmega optimal resistor and for a 80 N force. A special electronic circuit has been conceived in order to increase the power harvested by the piezoelectric transducer. This electrical converter applies the SSHI (synchronized switch harvesting on inductor) technique, and leads to remarkable results: under the same actuation conditions the generated power reaches 1.7 mW, which is sufficient to supply a large range of low consumption sensors. PMID:16814837
Electret transducer for vibration-based energy harvesting
NASA Astrophysics Data System (ADS)
Hillenbrand, J.; Pondrom, P.; Sessler, G. M.
2015-05-01
Vibration-based electret energy harvesters with soft cellular spacer rings are presented. These harvesters are closely related to recently introduced electret accelerometers; however, their development targets are partially differing. Various harvesters with seismic masses from 8 to 23 g and surface potentials in the 500 V regime were built and characterized and powers of up to 8 ?W at about 2 kHz and an acceleration of 1 g were measured. An analytical model is presented which, for instance, allows the calculation of the frequency response of the power output into a given load resistance. Finally, experimental and calculated results are compared.
Electret transducer for vibration-based energy harvesting
Hillenbrand, J. Sessler, G. M.; Pondrom, P.
2015-05-04
Vibration-based electret energy harvesters with soft cellular spacer rings are presented. These harvesters are closely related to recently introduced electret accelerometers; however, their development targets are partially differing. Various harvesters with seismic masses from 8 to 23?g and surface potentials in the 500?V regime were built and characterized and powers of up to 8??W at about 2?kHz and an acceleration of 1?g were measured. An analytical model is presented which, for instance, allows the calculation of the frequency response of the power output into a given load resistance. Finally, experimental and calculated results are compared.
A new figure of merit for wideband vibration energy harvesters
NASA Astrophysics Data System (ADS)
Liu, W. Q.; Badel, A.; Formosa, F.; Wu, Y. P.
2015-12-01
The performance evaluation method is a very important part in the field of vibration energy harvesting. It provides the ability to compare and rate different vibration energy harvesters (VEHs). Considering the lack of a well-recognized tool, this article proposed a new systematic figure of merit for the appraisement of wideband VEHs. Extensive investigations are first performed for some classic figures for linear VEHs. With the common fundamental information obtained, the proposed figure integrates four essential factors: the revised energy harvester effectiveness, the mechanical quality factor, the normalized bandwidth and the effective mass density. Special considerations are devoted to the properties of wideband VEHs about the operation range and the average power in this domain which are related to the performance target of stable power output. Afterward, this new figure is applied to some literature VEHs and demonstrated to present good evaluations of wideband VEHs. Moreover, it exhibits the ability to point out the improvement information of the concerned VEHs further developments.
Energy harvester array using piezoelectric circular diaphragm for broadband vibration
NASA Astrophysics Data System (ADS)
Xiao, Zhao; Yang, Tong qing; Dong, Ying; Wang, Xiu cai
2014-06-01
A piezoelectric generator fabricated by multiple circular diaphragm piezoelectric harvesters array is provided to harvest power over a broad range of frequencies. Four harvesters with varies tip masses are incorporated on a board with an area of 98 × 98 mm2. In this case, four strong output power peaks are obtained over frequencies from 120 Hz to 225 Hz. With an optimum load resistance of 15 k?, the value of four output power peaks is, respectively, 5.14, 6.65, 9.7, and 10 mW for the generator under an acceleration of 9.8 m/s2. By choosing an appropriate combination of tip masses with piezoelectric elements in array, the frequency range of energy harvesting can be obviously widened to meet the broadband vibration.
Model reduction in stochastic vibration energy harvesting using compressive sampling
NASA Astrophysics Data System (ADS)
Wickenheiser, A. M.
2013-09-01
Vibration energy harvesters are designed to gather parasitic energy from the motion of their host structures. In many germane scenarios, this motion is broadband; however, the preponderance of design criteria appearing in the literature for vibration energy harvesters considers sinusoidal base excitation at a single frequency. While this analysis often leads to analytical formulas for estimating power harvested, they fail to account for the contribution of multiple frequency components of the host motion and the excitation of higher vibration modes of the transducer. In this paper, an attempt is made to provide brief, analytical approximation of these additional factors. To wit, the single-mode, single-frequency power formula is extended to multi-frequency inputs and multiple modal excitations by matching each base acceleration frequency component to at most one mode of vibration whose half-power bandwidth that frequency falls within. Then, due to orthogonality, the expected power can be written as the sum of the contributions of the individual frequency components. To demonstrate the accuracy of this approximation, recorded acceleration signals from a car idling and a person walking are used as inputs, and predictions from the approximation are compared to results from full simulations. Approximations using only three frequency components are shown to be more than 80% accurate, with increased accuracy as the base acceleration signal becomes narrower in bandwidth. The effects of charge cancellation in the higher modes are also considered using simulations and the aforementioned approximations. These studies show that rectifying the strain in the higher modes is only beneficial if these modes contribute significantly to the power harvested. The approximate formulas derived in this paper are useful for making this determination.
Demonstration of Energy-Neutral Operation on a WSN Testbed Using Vibration Energy Harvesting
Uysal-Biyikoglu, Elif
Demonstration of Energy-Neutral Operation on a WSN Testbed Using Vibration Energy Harvesting S of a sensor node using vibration energy harvesting. Wireless Sensor Networks (WSN) have become essential components of automation and monitoring in today's general ICT infrastructure. A WSN is typically composed
Effect of electrode configurations on piezoelectric vibration energy harvesting performance
NASA Astrophysics Data System (ADS)
Kim, Miso; Dugundji, John; Wardle, Brian L.
2015-04-01
Piezoelectric vibration energy harvesting is an attractive technology for self-powered wireless sensor networks because of the potential to deliver power to the sensor nodes from mechanical vibration sources in the surrounding medium. Systematic device designs are required in order to increase performance along with materials development of high piezoelectric coefficients and design of circuits with high power transfer efficiency. In this work, we present refined structural and electrical modeling of interdigitated electrodes (IDEs) for piezoelectric vibration energy harvesting, followed by parametric case studies on MEMS devices. Differences in geometric parameters including the size of the electrode and the number of IDE fingers for given device dimensions lead to substantial changes in harvesting performance such as capacitance, system coupling, voltage and power. When compared with parallel plate electrodes, use of IDEs results in much higher voltage generation by a factor of ten times while similar power levels are observed for both {3-1} and {3-3} configurations at optimal electrical loading conditions.
Harvesting vibration energy by a triple-cantilever based triboelectric nanogenerator
Wang, Zhong L.
Harvesting vibration energy by a triple-cantilever based triboelectric nanogenerator Weiqing Yang1 vibration energy, triple-cantilever, self-powered systems ABSTRACT Triboelectric nanogenerators (TENG a rationally designed triple-cantilever based TENG for harvesting vibration energy. With the assistance
Multistable chain for ocean wave vibration energy harvesting
NASA Astrophysics Data System (ADS)
Harne, R. L.; Schoemaker, M. E.; Wang, K. W.
2014-03-01
The heaving of ocean waves is a largely untapped, renewable kinetic energy resource. Conversion of this energy into electrical power could integrate with solar technologies to provide for round-the-clock, portable, and mobile energy supplies usable in a wide variety of marine environments. However, the direct drive conversion methodology of gridintegrated wave energy converters does not efficiently scale down to smaller, portable architectures. This research develops an alternative power conversion approach to harness the extraordinarily large heaving displacements and long oscillation periods as an excitation source for an extendible vibration energy harvesting chain. Building upon related research findings and engineering insights, the proposed system joins together a series of dynamic cells through bistable interfaces. Individual impulse events are generated as the inertial mass of each cell is pulled across a region of negative stiffness to induce local snap through dynamics; the oscillating magnetic inertial mass then generates current in a coil which is connected to energy harvesting circuitry. It is shown that linking the cells into a chain transmits impulses through the system leading to cascades of vibration and enhancement of electrical energy conversion from each impulse event. This paper describes the development of the multistable chain and ways in which realistic design challenges were addressed. Numerical modeling and corresponding experiments demonstrate the response of the chain due to slow and large amplitude input motion. Lastly, experimental studies give evidence that energy conversion efficiency of the chain for wave energy conversion is much higher than using an equal number of cells without connections.
Harvesting vibration energy using two modal vibrations of a folded piezoelectric device
NASA Astrophysics Data System (ADS)
Gong, Li Jiao; Pan, Qiao Sheng; Li, Wei; Yan, Gang Yi; Liu, Yong Bin; Feng, Zhi Hua
2015-07-01
This letter reports a piezoelectric vibration energy harvester that uses the local lateral resonant modes of a folded structure to widen the operation frequency band. In addition, energy conversion efficiency is improved. A prototype energy harvester was fabricated and tested. The output power achieved two power peaks: 0.43 mW at 97 Hz and 6.64 mW at 120.9 Hz. The output power remained above 20 ?W within the operation frequency band that ranged from 88 Hz to 177 Hz when the energy harvester was driven with a vibration of 0.7 g peak acceleration. The output power remained higher than half of one of the maximum power peaks (0.43 mW) between 95 Hz and 101 Hz. Meanwhile, it remained higher than half of the other maximum power peak (6.64 mW) between 120.5 Hz and 123.8 Hz.
A piezomagnetoelastic structure for broadband vibration energy harvesting
NASA Astrophysics Data System (ADS)
Erturk, A.; Hoffmann, J.; Inman, D. J.
2009-06-01
This letter introduces a piezomagnetoelastic device for substantial enhancement of piezoelectric power generation in vibration energy harvesting. Electromechanical equations describing the nonlinear system are given along with theoretical simulations. Experimental performance of the piezomagnetoelastic generator exhibits qualitative agreement with the theory, yielding large-amplitude periodic oscillations for excitations over a frequency range. Comparisons are presented against the conventional case without magnetic buckling and superiority of the piezomagnetoelastic structure as a broadband electric generator is proven. The piezomagnetoelastic generator results in a 200% increase in the open-circuit voltage amplitude (hence promising an 800% increase in the power amplitude).
Efficiency enhancement of a cantilever-based vibration energy harvester.
Kubba, Ali E; Jiang, Kyle
2013-01-01
Extracting energy from ambient vibration to power wireless sensor nodes has been an attractive area of research, particularly in the automotive monitoring field. This article reports the design, analysis and testing of a vibration energy harvesting device based on a miniature asymmetric air-spaced cantilever. The developed design offers high power density, and delivers electric power that is sufficient to support most wireless sensor nodes for structural health monitoring (SHM) applications. The optimized design underwent three evolutionary steps, starting from a simple cantilever design, going through an air-spaced cantilever, and ending up with an optimized air-spaced geometry with boosted power density level. Finite Element Analysis (FEA) was used as an initial tool to compare the three geometries' stiffness (K), output open-circuit voltage (V(ave)), and average normal strain in the piezoelectric transducer (?(ave)) that directly affect its output voltage. Experimental tests were also carried out in order to examine the energy harvesting level in each of the three designs. The experimental results show how to boost the power output level in a thin air-spaced cantilever beam for energy within the same space envelope. The developed thin air-spaced cantilever (8.37 cm3), has a maximum power output of 2.05 mW (H = 29.29 ?J/cycle). PMID:24366177
Efficiency Enhancement of a Cantilever-Based Vibration Energy Harvester
Kubba, Ali E.; Jiang, Kyle
2014-01-01
Extracting energy from ambient vibration to power wireless sensor nodes has been an attractive area of research, particularly in the automotive monitoring field. This article reports the design, analysis and testing of a vibration energy harvesting device based on a miniature asymmetric air-spaced cantilever. The developed design offers high power density, and delivers electric power that is sufficient to support most wireless sensor nodes for structural health monitoring (SHM) applications. The optimized design underwent three evolutionary steps, starting from a simple cantilever design, going through an air-spaced cantilever, and ending up with an optimized air-spaced geometry with boosted power density level. Finite Element Analysis (FEA) was used as an initial tool to compare the three geometries' stiffness (K), output open-circuit voltage (Vave), and average normal strain in the piezoelectric transducer (?ave) that directly affect its output voltage. Experimental tests were also carried out in order to examine the energy harvesting level in each of the three designs. The experimental results show how to boost the power output level in a thin air-spaced cantilever beam for energy within the same space envelope. The developed thin air-spaced cantilever (8.37 cm3), has a maximum power output of 2.05 mW (H = 29.29 ?J/cycle). PMID:24366177
Analysis of Energy Harvesting for Vibration-Motivated Wireless Sensor Networks
Lim, Sunho
inherent pros and cons. When vibrations are a dominant source of energy and solar light is not alwaysAnalysis of Energy Harvesting for Vibration-Motivated Wireless Sensor Networks Sunho Lim Dept.com Abstract-- Extracting an electrical energy from various environmental sources, called energy harvesting (or
Harvesting energy from the natural vibration of human walking.
Yang, Weiqing; Chen, Jun; Zhu, Guang; Yang, Jin; Bai, Peng; Su, Yuanjie; Jing, Qingsheng; Cao, Xia; Wang, Zhong Lin
2013-12-23
The triboelectric nanogenerator (TENG), a unique technology for harvesting ambient mechanical energy based on the triboelectric effect, has been proven to be a cost-effective, simple, and robust approach for self-powered systems. However, a general challenge is that the output current is usually low. Here, we demonstrated a rationally designed TENG with integrated rhombic gridding, which greatly improved the total current output owing to the structurally multiplied unit cells connected in parallel. With the hybridization of both the contact-separation mode and sliding electrification mode among nanowire arrays and nanopores fabricated onto the surfaces of two contact plates, the newly designed TENG produces an open-circuit voltage up to 428 V, and a short-circuit current of 1.395 mA with the peak power density of 30.7 W/m(2). Relying on the TENG, a self-powered backpack was developed with a vibration-to-electric energy conversion efficiency up to 10.62(±1.19) %. And it was also demonstrated as a direct power source for instantaneously lighting 40 commercial light-emitting diodes by harvesting the vibration energy from natural human walking. The newly designed TENG can be a mobile power source for field engineers, explorers, and disaster-relief workers. PMID:24180642
Vibration-based energy harvesting with stacked piezoelectrets
Pondrom, P.; Hillenbrand, J.; Sessler, G. M.; Bös, J.; Melz, T.
2014-04-28
Vibration-based energy harvesters with multi-layer piezoelectrets (ferroelectrets) are presented. Using a simple setup with nine layers and a seismic mass of 8?g, it is possible to generate a power up to 1.3?µW at 140?Hz with an input acceleration of 1g. With better coupling between seismic mass and piezoelectret, and thus reduced damping, the power output of a single-layer system is increased to 5?µW at 700?Hz. Simulations indicate that for such improved setups with 10-layer stacks, utilizing seismic masses of 80?g, power levels of 0.1 to 1 mW can be expected below 100?Hz.
Vibration piezoelectric energy harvester with multi-beam
NASA Astrophysics Data System (ADS)
Cui, Yan; Zhang, Qunying; Yao, Minglei; Dong, Weijie; Gao, Shiqiao
2015-04-01
This work presents a novel vibration piezoelectric energy harvester, which is a micro piezoelectric cantilever with multi-beam. The characteristics of the PZT (Pb(Zr0.53Ti0.47)O3) thin film were measured; XRD (X-ray diffraction) pattern and AFM (Atomic Force Microscope) image of the PZT thin film were measured, and show that the PZT (Pb(Zr0.53Ti0.47)O3) thin film is highly (110) crystal oriented; the leakage current is maintained in nA magnitude, the residual polarisation Pr is 37.037 ?C/cm2, the coercive field voltage Ec is 27.083 kV/cm, and the piezoelectric constant d33 is 28 pC/N. In order to test the dynamic performance of the energy harvester, a new measuring system was set up. The maximum output voltage of the single beam of the multi-beam can achieve 80.78 mV under an acceleration of 1 g at 260 Hz of frequency; the maximum output voltage of the single beam of the multi-beam is almost 20 mV at 1400 Hz frequency.
New nonlinear vibration energy harvesters based on PVDF hybrid fluid diaphragm
NASA Astrophysics Data System (ADS)
Huet, F.; Formosa, F.; Badel, A.
2014-11-01
A low resonance frequency piezoelectric energy harvesting using a hybrid fluid diaphragm (HFD) is presented. This paper describes the design, fabrication and measurement of such device for harvesting energy from environmental vibrations. The HFD consists in an incompressible fluid confined between two thin piezoelectric membranes. The output voltage and power of the PVDF HFD are studied based on experimental and simulation results. Compared with conventional vibration harvester, this proposed solution is very simple and suitable for miniaturization and integration.
NASA Astrophysics Data System (ADS)
Beeby, Stephen P.; Wang, Leran; Zhu, Dibin; Weddell, Alex S.; Merrett, Geoff V.; Stark, Bernard; Szarka, Gyorgy; Al-Hashimi, Bashir M.
2013-07-01
The design of vibration energy harvesters (VEHs) is highly dependent upon the characteristics of the environmental vibrations present in the intended application. VEHs can be linear resonant systems tuned to particular frequencies or nonlinear systems with either bistable operation or a Duffing-type response. This paper provides detailed vibration data from a range of applications, which has been made freely available for download through the Energy Harvesting Network’s online data repository. In particular, this research shows that simulation is essential in designing and selecting the most suitable vibration energy harvester for particular applications. This is illustrated through C-based simulations of different types of VEHs, using real vibration data from a diesel ferry engine, a combined heat and power pump, a petrol car engine and a helicopter. The analysis shows that a bistable energy harvester only has a higher output power than a linear or Duffing-type nonlinear energy harvester with the same Q-factor when it is subjected to white noise vibration. The analysis also indicates that piezoelectric transduction mechanisms are more suitable for bistable energy harvesters than electromagnetic transduction. Furthermore, the linear energy harvester has a higher output power compared to the Duffing-type nonlinear energy harvester with the same Q factor in most cases. The Duffing-type nonlinear energy harvester can generate more power than the linear energy harvester only when it is excited at vibrations with multiple peaks and the frequencies of these peaks are within its bandwidth. Through these new observations, this paper illustrates the importance of simulation in the design of energy harvesting systems, with particular emphasis on the need to incorporate real vibration data.
Cryns, Jackson W.; Hatchell, Brian K.; Santiago-Rojas, Emiliano; Silvers, Kurt L.
2013-07-01
Formal journal article Experimental analysis of a piezoelectric energy harvesting system for harmonic, random, and sine on random vibration Abstract: Harvesting power with a piezoelectric vibration powered generator using a full-wave rectifier conditioning circuit is experimentally compared for varying sinusoidal, random and sine on random (SOR) input vibration scenarios. Additionally, the implications of source vibration characteristics on harvester design are discussed. Studies in vibration harvesting have yielded numerous alternatives for harvesting electrical energy from vibrations but piezoceramics arose as the most compact, energy dense means of energy transduction. The rise in popularity of harvesting energy from ambient vibrations has made piezoelectric generators commercially available. Much of the available literature focuses on maximizing harvested power through nonlinear processing circuits that require accurate knowledge of generator internal mechanical and electrical characteristics and idealization of the input vibration source, which cannot be assumed in general application. In this manuscript, variations in source vibration and load resistance are explored for a commercially available piezoelectric generator. We characterize the source vibration by its acceleration response for repeatability and transcription to general application. The results agree with numerical and theoretical predictions for in previous literature that load optimal resistance varies with transducer natural frequency and source type, and the findings demonstrate that significant gains are seen with lower tuned transducer natural frequencies for similar source amplitudes. Going beyond idealized steady state sinusoidal and simplified random vibration input, SOR testing allows for more accurate representation of real world ambient vibration. It is shown that characteristic interactions from more complex vibrational sources significantly alter power generation and power processing requirements by increasing harvested power, shifting optimal conditioning impedance, inducing significant voltage supply fluctuations and ultimately rendering idealized sinusoidal and random analyses insufficient.
A diamagnetically stabilized horizontally levitated electromagnetic vibration energy harvester
NASA Astrophysics Data System (ADS)
Palagummi, S.; Zou, J.; Yuan, F. G.
2015-04-01
This article investigates a horizontal diamagnetic levitation (HDL) system for vibration energy harvesting. In this configuration, two large magnets, alias lifting magnets, are arranged co-axially at a distance such that in between them a magnet, alias floating magnet, is passively levitated at a laterally offset equilibrium position. The levitation is stabilized in the horizontal direction by two diamagnetic plates made of pyrolytic graphite placed on each side of the floating magnet. This HDL configuration permits large amplitude vibration of the floating magnet and exploits the ability to tailor the geometry to meet specific applications due to its frequency tuning capability. Theoretical modeling techniques are discussed followed by an experimental setup to validate it. At an input root mean square (RMS) acceleration of 0.0434 m/s2 (0.0044 grms) and at a resonant frequency of 1.2 Hz, the prototype generated a RMS power of 3.6 ?W with an average system efficiency of 1.93%. Followed by the validation, parametric studies on the geometry of the components are undertaken to show that with the optimized parameters the efficiency can be further enhanced.
A Study on Energy Harvesting Aware Routing for Vibration-Motivated Wireless Sensor Networks
Lim, Sunho
A Study on Energy Harvesting Aware Routing for Vibration-Motivated Wireless Sensor Networks TTU an electrical energy from various environmental sources, called energy harvesting (or energy scavenging), has been an issue and attracting researchers' attention in energy replenishable networks. In par- ticular
A dimensionless analysis of a 2DOF piezoelectric vibration energy harvester
NASA Astrophysics Data System (ADS)
Xiao, Han; Wang, Xu; John, Sabu
2015-06-01
In this study, a dimensionless analysis method is proposed to predict the output voltage and harvested power for a 2DOF vibration energy harvesting system. This method allows us to compare the harvesting power and efficiency of the 2DOF vibration energy harvesting system and to evaluate the harvesting system performance regardless the sizes or scales. The analysis method is a hybrid of time domain simulation and frequency response analysis approaches, which would be a useful tool for parametric study, design and optimisation of a 2DOF piezoelectric vibration energy harvester. In a case study, a quarter car suspension model with a piezoelectric material insert is chosen to be studied. The 2DOF vibration energy harvesting system could potentially be applied in a vehicle to convert waste or harmful ambient vibration energy into electrical energy for charging the battery. Especially for its application in a hybrid vehicle or an electrical vehicle, the 2DOF vibration energy harvesting system could improve charge mileage, comfort and reliability.
Vibration energy harvesting using a phononic crystal with point defect states
NASA Astrophysics Data System (ADS)
Lv, Hangyuan; Tian, Xiaoyong; Wang, Michael Yu; Li, Dichen
2013-01-01
A vibration energy harvesting generator was studied in the present research using point-defect phononic crystal with piezoelectric material. By removing a rod from a perfect phononic crystal, a resonant cavity was formed. The elastic waves in the range of gap frequencies were all forbidden in any direction, while the waves with resonant frequency were localized and enhanced in the resonant cavity. The collected vibration energy was converted into electric energy by putting a polyvinylidene fluoride film in the middle of the defect. This structure can be used to simultaneously realize both vibration damping and broad-distributed vibration energy harvesting.
Kumar, Ratnesh
Abstract--This paper presents ambient mechanical vibrations as an alternative source for energy harvesting, especially beneficial where alternatives such as light, wind, biomass and thermal energy are limited, e.g., powering underground sensors. Transduction of ambient kinetic energy, e.g., the vibrations
NASA Astrophysics Data System (ADS)
Miller, Lindsay Margaret
Wireless sensor networks (WSNs) have the potential to transform engineering infrastructure, manufacturing, and building controls by allowing condition monitoring, asset tracking, demand response, and other intelligent feedback systems. A wireless sensor node consists of a power supply, sensor(s), power conditioning circuitry, radio transmitter and/or receiver, and a micro controller. Such sensor nodes are used for collecting and communicating data regarding the state of a machine, system, or process. The increasing demand for better ways to power wireless devices and increase operation time on a single battery charge drives an interest in energy harvesting research. Today, wireless sensor nodes are typically powered by a standard single-charge battery, which becomes depleted within a relatively short timeframe depending on the application. This introduces tremendous labor costs associated with battery replacement, especially when there are thousands of nodes in a network, the nodes are remotely located, or widely-distributed. Piezoelectric vibration energy harvesting presents a potential solution to the problems associated with too-short battery life and high maintenance requirements, especially in industrial environments where vibrations are ubiquitous. Energy harvester designs typically use the harvester to trickle charge a rechargeable energy storage device rather than directly powering the electronics with the harvested energy. This allows a buffer between the energy harvester supply and the load where energy can be stored in a "tank". Therefore, the harvester does not need to produce the full required power at every instant to successfully power the node. In general, there are tens of microwatts of power available to be harvested from ambient vibrations using micro scale devices and tens of milliwatts available from ambient vibrations using meso scale devices. Given that the power requirements of wireless sensor nodes range from several microwatts to about one hundred milliwatts and are falling steadily as improvements are made, it is feasible to use energy harvesting to power WSNs. This research begins by presenting the results of a thorough survey of ambient vibrations in the machine room of a large campus building, which found that ambient vibrations are low frequency, low amplitude, time varying, and multi-frequency. The modeling and design of fixed-frequency micro scale energy harvesters are then presented. The model is able to take into account rotational inertia of the harvester's proof mass and it accepts arbitrary measured acceleration input, calculating the energy harvester's voltage as an output. The fabrication of the micro electromechanical system (MEMS) energy harvesters is discussed and results of the devices harvesting energy from ambient vibrations are presented. The harvesters had resonance frequencies ranging from 31 - 232 Hz, which was the lowest reported in literature for a MEMS device, and produced 24 pW/g2 - 10 nW/g2 of harvested power from ambient vibrations. A novel method for frequency modification of the released harvester devices using a dispenser printed mass is then presented, demonstrating a frequency shift of 20 Hz. Optimization of the MEMS energy harvester connected to a resistive load is then presented, finding that the harvested power output can be increased to several microwatts with the optimized design as long as the driving frequency matches the harvester's resonance frequency. A framework is then presented to allow a similar optimization to be conducted with the harvester connected to a synchronously switched pre-bias circuit. With the realization that the optimized energy harvester only produces usable amounts of power if the resonance frequency and driving frequency match, which is an unrealistic situation in the case of ambient vibrations which change over time and are not always known
Piezoelectric-based power sources for harvesting energy from platforms with low-frequency vibration
NASA Astrophysics Data System (ADS)
Rastegar, J.; Pereira, C.; Nguyen, H.-L.
2006-03-01
This paper presents a new class of highly efficient piezoelectric based energy harvesting power sources for mounting on platforms that vibrate at very low frequencies as compared to the frequencies at which energy can be efficiently harvested using piezoelectric elements . These energy harvesting power sources have a very simple design and do not require accurate tuning for each application to match the frequency of the platform vibration. The developed method of harvesting mechanical energy and converting it to electrical energy overcomes problems that are usually encountered with harvesting energy from low frequency vibration of various platforms such as ships and other platforms with similar vibratory (rocking or translational) motions. Omnitek Partners has designed several such energy harvesting power sources and is in the process of constructing prototypes for testing. The developed designs are modular and can be used to construct power sources for various power requirements. The amount of mechanical energy available for harvesting is obviously dependent on the frequency and amplitude of vibration of the platform, and the size and mass of the power source.
A hybrid indoor ambient light and vibration energy harvester for wireless sensor nodes.
Yu, Hua; Yue, Qiuqin; Zhou, Jielin; Wang, Wei
2014-01-01
To take advantage of applications where both light and vibration energy are available, a hybrid indoor ambient light and vibration energy harvesting scheme is proposed in this paper. This scheme uses only one power conditioning circuit to condition the combined output power harvested from both energy sources so as to reduce the power dissipation. In order to more accurately predict the instantaneous power harvested from the solar panel, an improved five-parameter model for small-scale solar panel applying in low light illumination is presented. The output voltage is increased by using the MEMS piezoelectric cantilever arrays architecture. It overcomes the disadvantage of traditional MEMS vibration energy harvester with low voltage output. The implementation of the maximum power point tracking (MPPT) for indoor ambient light is implemented using analog discrete components, which improves the whole harvester efficiency significantly compared to the digital signal processor. The output power of the vibration energy harvester is improved by using the impedance matching technique. An efficient mechanism of energy accumulation and bleed-off is also discussed. Experiment results obtained from an amorphous-silicon (a-Si) solar panel of 4.8 × 2.0 cm2 and a fabricated piezoelectric MEMS generator of 11 × 12.4 mm2 show that the hybrid energy harvester achieves a maximum efficiency around 76.7%. PMID:24854054
Ostasevicius, Vytautas; Janusas, Giedrius; Milasauskaite, Ieva; Zilys, Mindaugas; Kizauskiene, Laura
2015-01-01
This paper focuses on several aspects extending the dynamical efficiency of a cantilever beam vibrating in the third mode. A few ways of producing this mode stimulation, namely vibro-impact or forced excitation, as well as its application for energy harvesting devices are proposed. The paper presents numerical and experimental analyses of novel structural dynamics effects along with an optimal configuration of the cantilever beam. The peculiarities of a cantilever beam vibrating in the third mode are related to the significant increase of the level of deformations capable of extracting significant additional amounts of energy compared to the conventional harvester vibrating in the first mode. Two types of a piezoelectric vibrating energy harvester (PVEH) prototype are analysed in this paper: the first one without electrode segmentation, while the second is segmented using electrode segmentation at the strain nodes of the third vibration mode to achieve effective operation at the third resonant frequency. The results of this research revealed that the voltage generated by any segment of the segmented PVEH prototype excited at the third resonant frequency demonstrated a 3.4-4.8-fold increase in comparison with the non-segmented prototype. Simultaneously, the efficiency of the energy harvester prototype also increased at lower resonant frequencies from 16% to 90%. The insights presented in the paper may serve for the development and fabrication of advanced piezoelectric energy harvesters which would be able to generate a considerably increased amount of electrical energy independently of the frequency of kinematical excitation. PMID:26029948
Ostasevicius, Vytautas; Janusas, Giedrius; Milasauskaite, Ieva; Zilys, Mindaugas; Kizauskiene, Laura
2015-01-01
This paper focuses on several aspects extending the dynamical efficiency of a cantilever beam vibrating in the third mode. A few ways of producing this mode stimulation, namely vibro-impact or forced excitation, as well as its application for energy harvesting devices are proposed. The paper presents numerical and experimental analyses of novel structural dynamics effects along with an optimal configuration of the cantilever beam. The peculiarities of a cantilever beam vibrating in the third mode are related to the significant increase of the level of deformations capable of extracting significant additional amounts of energy compared to the conventional harvester vibrating in the first mode. Two types of a piezoelectric vibrating energy harvester (PVEH) prototype are analysed in this paper: the first one without electrode segmentation, while the second is segmented using electrode segmentation at the strain nodes of the third vibration mode to achieve effective operation at the third resonant frequency. The results of this research revealed that the voltage generated by any segment of the segmented PVEH prototype excited at the third resonant frequency demonstrated a 3.4–4.8-fold increase in comparison with the non-segmented prototype. Simultaneously, the efficiency of the energy harvester prototype also increased at lower resonant frequencies from 16% to 90%. The insights presented in the paper may serve for the development and fabrication of advanced piezoelectric energy harvesters which would be able to generate a considerably increased amount of electrical energy independently of the frequency of kinematical excitation. PMID:26029948
Chaos control applied to piezoelectric vibration-based energy harvesting systems
NASA Astrophysics Data System (ADS)
Barbosa, W. O. V.; De Paula, A. S.; Savi, M. A.; Inman, D. J.
2015-11-01
Chaotic behavior presents intrinsic richness due to the existence of an infinity number of unstable periodic orbits (UPOs). The possibility of stabilizing these periodic patterns with a small amount of energy makes this kind of response interesting to various dynamical systems. Energy harvesting has as a goal the use of available mechanical energy by promoting a conversion into electrical energy. The combination of these two approaches may establish autonomous systems where available environmental mechanical energy can be employed for control purposes. Two different goals can be defined as priority, allowing a change between them: vibration reduction and energy harvesting enhancement. This work deals with the use of harvested energy to perform chaos control. Both control actuation and energy harvesting are induced employing piezoelectric materials, in a simultaneous way. A bistable piezomagnetoelastic structure subjected to harmonic excitations is investigated as a case study. Numerical simulations show situations where it is possible to perform chaos control using only the energy generated by the harvesting system.
NASA Astrophysics Data System (ADS)
Renaud, M.; Fujita, T.; Goedbloed, M.; de Nooijer, C.; van Schaijk, R.
2014-11-01
Current commercial wireless tire pressure monitoring systems (TPMS) require a battery as electrical power source. The battery limits the lifetime of the TPMS. This limit can be circumvented by replacing the battery by a vibration energy harvester. Autonomous wireless TPMS powered by MEMS electret based vibration energy harvester have been demonstrated. A remaining technical challenge to attain the grade of commercial product with these autonomous TPMS is the mechanical reliability of the MEMS harvester. It should survive the harsh conditions imposed by the tire environment, particularly in terms of mechanical shocks. As shown in this article, our first generation of harvesters has a shock resilience of 400 g, which is far from being sufficient for the targeted application. In order to improve this aspect, several types of shock absorbing structures are investigated. With the best proposed solution, the shock resilience of the harvesters is brought above 2500 g.
Shock reliability analysis and improvement of MEMS electret-based vibration energy harvesters
NASA Astrophysics Data System (ADS)
Renaud, M.; Fujita, T.; Goedbloed, M.; de Nooijer, C.; van Schaijk, R.
2015-10-01
Vibration energy harvesters can serve as a replacement solution to batteries for powering tire pressure monitoring systems (TPMS). Autonomous wireless TPMS powered by microelectromechanical system (MEMS) electret-based vibration energy harvester have been demonstrated. The mechanical reliability of the MEMS harvester still has to be assessed in order to bring the harvester to the requirements of the consumer market. It should survive the mechanical shocks occurring in the tire environment. A testing procedure to quantify the shock resilience of harvesters is described in this article. Our first generation of harvesters has a shock resilience of 400?g, which is far from being sufficient for the targeted application. In order to improve this aspect, the first important aspect is to understand the failure mechanism. Failure is found to occur in the form of fracture of the device’s springs. It results from impacts between the anchors of the springs when the harvester undergoes a shock. The shock resilience of the harvesters can be improved by redirecting these impacts to nonvital parts of the device. With this philosophy in mind, we design three types of shock absorbing structures and test their effect on the shock resilience of our MEMS harvesters. The solution leading to the best results consists of rigid silicon stoppers covered by a layer of Parylene. The shock resilience of the harvesters is brought above 2500?g. Results in the same range are also obtained with flexible silicon bumpers, which are simpler to manufacture.
NASA Astrophysics Data System (ADS)
Wickenheiser, Adam; Garcia, Ephrahim
2010-04-01
In much of the vibration-based energy harvesting literature, devices are modeled, designed, and tested for dissipating energy across a resistive load at a single base excitation frequency. This paper presents several practical scenarios germane to tracking, sensing, and wireless communication on humans and land vehicles. Measured vibrational data from these platforms are used to provide a time-varying, broadband input to the energy harvesting system. Optimal power considerations are given for several circuit topologies, including a passive rectifier circuit and active, switching methods. Under various size and mass constraints, the optimal design is presented for two scenarios: walking and idling a car. The frequency response functions are given alongside time histories of the power harvested using the experimental base accelerations recorded. The issues involved in designing an energy harvester for practical (i.e. timevarying, non-sinusoidal) applications are discussed.
Roles of the Excitation in Harvesting Energy from Vibrations
Zhang, Hui; Ma, Tianwei
2015-01-01
The study investigated the role of excitation in energy harvesting applications. While the energy ultimately comes from the excitation, it was shown that the excitation may not always behave as a source. When the device characteristics do not perfectly match the excitation, the excitation alternately behaves as a source and a sink. The extent to which the excitation behaves as a sink determines the energy harvesting efficiency. Such contradictory roles were shown to be dictated by a generalized phase defined as the instantaneous phase angle between the velocity of the device and the excitation. An inductive prototype device with a diamagnetically levitated seismic mass was proposed to take advantage of the well established phase changing mechanism of vibro-impact to achieve a broader device bandwidth. Results suggest that the vibro-impact can generate an instantaneous, significant phase shift in response velocity that switches the role of the excitation. If introduced properly outside the resonance zone it could dramatically increase the energy harvesting efficiency. PMID:26496183
NASA Astrophysics Data System (ADS)
Bibo, A.; Daqaq, M. F.
2013-06-01
In this letter, a single vibratory energy harvester integrated with an airfoil is proposed to concurrently harness energy from ambient vibrations and wind. In terms of its transduction capabilities and power density, the integrated device is shown to have a superior performance under the combined loading when compared to utilizing two separate devices to harvest energy independently from the two available energy sources. Even below its flutter speed, the proposed device was able to provide 2.5 times the power obtained using two separate harvesters.
Powering pacemakers from heartbeat vibrations using linear and nonlinear energy harvesters
NASA Astrophysics Data System (ADS)
Amin Karami, M.; Inman, Daniel J.
2012-01-01
Linear and nonlinear piezoelectric devices are introduced to continuously recharge the batteries of the pacemakers by converting the vibrations from the heartbeats to electrical energy. The power requirement of a pacemaker is very low. However, after few years, patients require another surgical operation just to replace their pacemaker battery. Linear low frequency and nonlinear mono-stable and bi-stable energy harvesters are designed according to the especial signature of heart vibrations. The proposed energy harvesters are robust to variation of heart rate and can meet the power requirement of pacemakers.
Magnetostrictive vibration damper and energy harvester for rotating machinery
NASA Astrophysics Data System (ADS)
Deng, Zhangxian; Asnani, Vivake M.; Dapino, Marcelo J.
2015-04-01
Vibrations generated by machine driveline components can cause excessive noise and structural dam- age. Magnetostrictive materials, including Galfenol (iron-gallium alloys) and Terfenol-D (terbium-iron- dysprosium alloys), are able to convert mechanical energy to magnetic energy. A magnetostrictive vibration ring is proposed, which generates electrical energy and dampens vibration, when installed in a machine driveline. A 2D axisymmetric finite element (FE) model incorporating magnetic, mechanical, and electrical dynamics is constructed in COMSOL Multiphysics. Based on the model, a parametric study considering magnetostrictive material geometry, pickup coil size, bias magnet strength, flux path design, and electrical load is conducted to maximize loss factor and average electrical output power. By connecting various resistive loads to the pickup coil, the maximum loss factors for Galfenol and Terfenol-D due to electrical energy loss are identified as 0.14 and 0.34, respectively. The maximum av- erage electrical output power for Galfenol and Terfenol-D is 0.21 W and 0.58 W, respectively. The loss factors for Galfenol and Terfenol-D are increased to 0.59 and 1.83, respectively, by using an L-C resonant circuit.
Magnetostrictive Vibration Damper and Energy Harvester for Rotating Machinery
NASA Technical Reports Server (NTRS)
Deng, Zhangxian; Asnani, Vivake M.; Dapino, Marcelo J.
2015-01-01
Vibrations generated by machine driveline components can cause excessive noise and structural damage. Magnetostrictive materials, including Galfenol (iron-gallium alloys) and Terfenol-D (terbium-iron-dysprosium alloys), are able to convert mechanical energy to magnetic energy. A magnetostrictive vibration ring is proposed, which generates electrical energy and dampens vibration, when installed in a machine driveline. A 2D axisymmetric finite element (FE) model incorporating magnetic, mechanical, and electrical dynamics is constructed in COMSOL Multiphysics. Based on the model, a parametric study considering magnetostrictive material geometry, pickup coil size, bias magnet strength, flux path design, and electrical load is conducted to maximize loss factor and average electrical output power. By connecting various resistive loads to the pickup coil, the maximum loss factors for Galfenol and Terfenol-D due to electrical energy loss are identified as 0.14 and 0.34, respectively. The maximum average electrical output power for Galfenol and Terfenol-D is 0.21 W and 0.58 W, respectively. The loss factors for Galfenol and Terfenol-D are increased to 0.59 and 1.83, respectively, by using an L-C resonant circuit.
Sun, Kyung Ho; Kim, Young-Cheol; Kim, Jae Eun
2014-10-15
While environmental vibrations are usually in the range of a few hundred Hertz, small-form-factor piezoelectric vibration energy harvesters will have higher resonant frequencies due to the structural size effect. To address this issue, we propose a resonant frequency-down conversion based on the theory of dynamic vibration absorber for the design of a small-form-factor piezoelectric vibration energy harvester. The proposed energy harvester consists of two frequency-tuned elastic components for lowering the first resonant frequency of an integrated system but is so configured that an energy harvesting beam component is inverted with respect to the other supporting beam component for a small form factor. Furthermore, in order to change the unwanted modal characteristic of small separation of resonant frequencies, as is the case with an inverted configuration, a proof mass on the supporting beam component is slightly shifted toward a second proof mass on the tip of the energy harvesting beam component. The proposed small-form-factor design capability was experimentally verified using a fabricated prototype with an occupation volume of 20 × 39 × 6.9 mm{sup 3}, which was designed for a target frequency of as low as 100 Hz.
Regular and chaotic vibration in a piezoelectric energy harvester with fractional damping
NASA Astrophysics Data System (ADS)
Cao, Junyi; Syta, Arkadiusz; Litak, Grzegorz; Zhou, Shengxi; Inman, Daniel J.; Chen, Yangquan
2015-06-01
We examine a vibrational energy harvester consisting of a mechanical resonator with a fractional damping and electrical circuit coupled by a piezoelectric converter. By comparing the bifurcation diagrams and the power output we show that the fractional order of damping changes the system response considerably and affects the power output. Various dynamic responses of the energy harvester are examined using phase trajectory, Fourier spectrum, Multi-scale entropy and 0-1 test. The numerical analysis shows that the fractionally damped energy harvesting system exhibits chaos, and periodic motion, as the fractional order changes. The observed bifurcations strongly influence the power output.
NASA Astrophysics Data System (ADS)
Fan, Kang-Qi; Ming, Zheng-Feng; Xu, Chun-Hui; Chao, Feng-Bo
2013-10-01
As an alternative power solution for low-power devices, harvesting energy from the ambient mechanical vibration has received increasing research interest in recent years. In this paper we study the transient dynamic characteristics of a piezoelectric energy harvesting system including a piezoelectric energy harvester, a bridge rectifier, and a storage capacitor. To accomplish this, this energy harvesting system is modeled, and the charging process of the storage capacitor is investigated by employing the in-phase assumption. The results indicate that the charging voltage across the storage capacitor and the gathered power increase gradually as the charging process proceeds, whereas the charging rate slows down over time as the charging voltage approaches to the peak value of the piezoelectric voltage across the piezoelectric materials. In addition, due to the added electrical damping and the change of the system natural frequency when the charging process is initiated, a sudden drop in the vibration amplitude is observed, which in turn affects the charging rate. However, the vibration amplitude begins to increase as the charging process continues, which is caused by the decrease in the electrical damping (i.e., the decrease in the energy removed from the mechanical vibration). This electromechanical coupling characteristic is also revealed by the variation of the vibration amplitude with the charging voltage.
NASA Astrophysics Data System (ADS)
Dhote, Sharvari; Zu, Jean; Zhu, Yang
2015-04-01
In this paper, a nonlinear wideband multi-mode piezoelectric vibration-based energy harvester (PVEH) is proposed based on a compliant orthoplanar spring (COPS), which has an advantage of providing multiple vibration modes at relatively low frequencies. The PVEH is made of a tri-leg COPS flexible structure, where three fixed-guided beams are capable of generating strong nonlinear oscillations under certain base excitation. A prototype harvester was fabricated and investigated through both finite-element analysis and experiments. The frequency response shows multiple resonance which corresponds to a hardening type of nonlinear resonance. By adding masses at different locations on the COPS structure, the first three vibration modes are brought close to each other, where the three hardening nonlinear resonances provide a wide bandwidth for the PVEH. The proposed PVEH has enhanced performance of the energy harvester in terms of a wide frequency bandwidth and a high-voltage output under base excitations.
Dhote, Sharvari Zu, Jean; Zhu, Yang
2015-04-20
In this paper, a nonlinear wideband multi-mode piezoelectric vibration-based energy harvester (PVEH) is proposed based on a compliant orthoplanar spring (COPS), which has an advantage of providing multiple vibration modes at relatively low frequencies. The PVEH is made of a tri-leg COPS flexible structure, where three fixed-guided beams are capable of generating strong nonlinear oscillations under certain base excitation. A prototype harvester was fabricated and investigated through both finite-element analysis and experiments. The frequency response shows multiple resonance which corresponds to a hardening type of nonlinear resonance. By adding masses at different locations on the COPS structure, the first three vibration modes are brought close to each other, where the three hardening nonlinear resonances provide a wide bandwidth for the PVEH. The proposed PVEH has enhanced performance of the energy harvester in terms of a wide frequency bandwidth and a high-voltage output under base excitations.
Design improvements for an electret-based MEMS vibrational electrostatic energy harvester
NASA Astrophysics Data System (ADS)
Altena, G.; Renaud, M.; Elfrink, R.; Goedbloed, M. H.; de Nooijer, C.; van Schaijk, R.
2013-12-01
This paper presents several improvements to the design of an electret-based MEMS vibrational electrostatic energy harvester that have led to a two orders of magnitude increase in power compared to a previously presented device. The device in this paper has a footprint of approximately 1 cm2 and generated 175 ?W. The following two improvements to the design are discussed: the electrical connection principle of the harvester and the electrode geometrical configuration. The measured performance of the device is compared with simulations. When exited by sinusoidal vibration, a device employing the two design improvements but with a higher resonance frequency and higher electret potential generated 495 ?W AC power, which is the highest reported value for electret-based MEMS vibrational electrostatic energy harvesters with a similar footprint. This makes this device a promising candidate for the targeted application of wireless tire pressure monitoring systems (TPMS).
On the efficiency of energy harvesting using vortex-induced vibrations of cables
Grouthier, Clement; Bourguet, Remi; Modarres-Sadeghi, Yahya; de Langre, Emmanuel
2014-01-01
Many technologies based on fluid-structure interaction mechanisms are being developed to harvest energy from geophysical flows. The velocity of such flows is low, and so is their energy density. Large systems are therefore required to extract a significant amount of energy. The question of the efficiency of energy harvesting using vortex-induced vibrations (VIV) of cables is addressed in this paper, through two reference configurations: (i) a long tensioned cable with periodically-distributed harvesters and (ii) a hanging cable with a single harvester at its upper extremity. After validation against either direct numerical simulations or experiments, an appropriate reduced-order wake- oscillator model is used to perform parametric studies of the impact of the harvesting parameters on the efficiency. For both configurations, an optimal set of parameters is identified and it is shown that the maximum efficiency is close to the value reached with an elastically-mounted rigid cylinder. The variability of the effi...
Adaptive tuned piezoelectric MEMS vibration energy harvester using an electrostatic device
NASA Astrophysics Data System (ADS)
Madinei, H.; Khodaparast, H. Haddad; Adhikari, S.; Friswell, M. I.; Fazeli, M.
2015-11-01
In this paper an adaptive tuned piezoelectric vibration based energy harvesting system based on the use of electrostatic device is proposed. The main motivation is to control the resonance frequency of the piezoelectric harvester with the DC voltage applied to the electrostatic system in order to maximize the harvested power. The idea is demonstrated in a hybrid system consisting of a cantilevered piezoelectric harvester combined with an electrostatic harvester which is connected to a variable voltage source. The nonlinear governing differential equation of motion is derived based on Euler Bernoulli theory, and solved to obtain the static and dynamic solutions. The results show that the harvester can be tuned to give a resonant response over a wide range of frequencies, and shows the great potential of this hybrid system.
Self-suspended vibration-driven energy harvesting chip for power density maximization
NASA Astrophysics Data System (ADS)
Murillo, Gonzalo; Agustí, Jordi; Abadal, Gabriel
2015-11-01
This work introduces a new concept to integrate energy-harvesting devices with the aim of improving their throughput, mainly in terms of scavenged energy density and frequency tunability. This concept, named energy harvester in package (EHiP), is focused on the heterogeneous integration of a MEMS die, dedicated to scavenging energy, with an auxiliary chip, which can include the control and power management circuitry, sensors and RF transmission capabilities. The main advantages are that the whole die can be used as an inertial mass and the chip area usage is optimized. Based on this concept, in this paper we describe the development and characterization of a MEMS die fully dedicated to harvesting mechanical energy from ambient vibrations through an electrostatic transduction. A test PCB has been fabricated to perform the assembly that allows measurement of the resonance motion of the whole system at 289 Hz. An estimated maximum generated power of around 11 ?W has been obtained for an input vibration acceleration of ˜10 m s-2 when the energy harvester operates in a constant-charge cycle for the best-case scenario. Therefore, a maximum scavenged power density of 0.85 mW cm-3 is theoretically expected for the assembled system. These results demonstrate that the generated power density of any vibration-based energy harvester can be significantly increased by applying the EHiP concept, which could become an industrial standard for manufacturing this kind of system, independently of the transduction type, fabrication technology or application.
Lan, C. B.; Qin, W. Y.
2014-09-15
This letter investigates the energy harvesting from the horizontal coherent resonance of a vertical cantilever beam subjected to the vertical base excitation. The potential energy of the system has two symmetric potential wells. So, under vertical excitation, the system can jump between two potential wells, which will lead to the large vibration in horizontal direction. Two piezoelectric patches are pasted to harvest the energy. From experiment, it is found that the vertical excitation can make the beam turn to be bistable. The system can transform vertical vibration into horizontal vibration of low frequency when excited by harmonic motion. The horizontal coherence resonance can be observed when excited by a vertical white noise. The corresponding output voltages of piezoelectric films reach high values.
Coupled analysis of multi-impact energy harvesting from low-frequency wind induced vibrations
NASA Astrophysics Data System (ADS)
Zhu, Jin; Zhang, Wei
2015-04-01
Energy need from off-grid locations has been critical for effective real-time monitoring and control to ensure structural safety and reliability. To harvest energy from ambient environments, the piezoelectric-based energy-harvesting system has been proven very efficient to convert high frequency vibrations into usable electrical energy. However, due to the low frequency nature of the vibrations of civil infrastructures, such as those induced from vehicle impacts, wind, and waves, the application of a traditional piezoelectric-based energy-harvesting system is greatly restrained since the output power drops dramatically with the reduction of vibration frequencies. This paper focuses on the coupled analysis of a proposed piezoelectric multi-impact wind-energy-harvesting device that can effectively up-convert low frequency wind-induced vibrations into high frequency ones. The device consists of an H-shape beam and four bimorph piezoelectric cantilever beams. The H-shape beam, which can be easily triggered to vibrate at a low wind speed, is originated from the first Tacoma Narrows Bridge, which failed at wind speeds of 18.8 m s-1 in 1940. The multi-impact mechanism between the H-shape beam and the bimorph piezoelectric cantilever beams is incorporated to improve the harvesting performance at lower frequencies. During the multi-impact process, a series of sequential impacts between the H-shape beam and the cantilever beams can trigger high frequency vibrations of the cantilever beams and result in high output power with a considerably high efficiency. In the coupled analysis, the coupled structural, aerodynamic, and electrical equations are solved to obtain the dynamic response and the power output of the proposed harvesting device. A parametric study for several parameters in the coupled analysis framework is carried out including the external resistance, wind speed, and the configuration of the H-shape beam. The average harvested power for the piezoelectric cantilever beam reaches 11.77 mW with a power density of 6.11 mW cm-3 under the wind speed of 10 m s-1, which is sufficient to power small sensors. The average harvested power can further reach up to 45 mW under the wind speed of 14 m s-1.
Nonlinear vibration analysis of the high-efficiency compressive-mode piezoelectric energy harvester
NASA Astrophysics Data System (ADS)
Yang, Zhengbao; Zu, Jean
2015-04-01
Power source is critical to achieve independent and autonomous operations of electronic mobile devices. The vibration-based energy harvesting is extensively studied recently, and recognized as a promising technology to realize inexhaustible power supply for small-scale electronics. Among various approaches, the piezoelectric energy harvesting has gained the most attention due to its high conversion efficiency and simple configurations. However, most of piezoelectric energy harvesters (PEHs) to date are based on bending-beam structures and can only generate limited power with a narrow working bandwidth. The insufficient electric output has greatly impeded their practical applications. In this paper, we present an innovative lead zirconate titanate (PZT) energy harvester, named high-efficiency compressive-mode piezoelectric energy harvester (HC-PEH), to enhance the performance of energy harvesters. A theoretical model was developed analytically, and solved numerically to study the nonlinear characteristics of the HC-PEH. The results estimated by the developed model agree well with the experimental data from the fabricated prototype. The HC-PEH shows strong nonlinear responses, favorable working bandwidth and superior power output. Under a weak excitation of 0.3 g (g = 9.8 m/s2), a maximum power output 30 mW is generated at 22 Hz, which is about ten times better than current energy harvesters. The HC-PEH demonstrates the capability of generating enough power for most of wireless sensors.
NASA Astrophysics Data System (ADS)
Eltanany, Ali M.; Yoshimura, Takeshi; Fujimura, Norifumi; Elsayed, Nour Z.; Ebied, Mohamed R.; Ali, Mohamed G. S.
2015-10-01
The role of nonlinear stiffness in the performance of the piezoelectric vibrational energy harvester (pVEH) was discussed. Harmonic balance and numerical methods are applied to characterize the electromechanical response of pVEHs based on Duffing oscillator at a deterministic harmonic excitation of fundamental vibration characteristics (2 Hz, 1 m·s-2), which corresponds to human walking. Then, the response to a vibration with two harmonic waves, which has a fixed fundamental frequency (2 Hz, 1 m·s-2) and a frequency varied from 1.5 to 2.5 Hz. The numerical results obtained in this study indicate that nonlinearity does not have a significant advantage on the energy harvesting from human walking.
Small-scale energy harvesting through thermoelectric, vibration, and radiofrequency power conversion
NASA Astrophysics Data System (ADS)
Hudak, Nicholas S.; Amatucci, Glenn G.
2008-05-01
As sensors for a wide array of applications continue to shrink and become integrated, increasing attention has been focused on creating autonomous devices with long-lasting power supplies. To achieve this, energy will have to be harvested from the sensors' environment. An energy harvesting device can power the sensor either directly or in conjunction with a battery. Presented herein is a review of three types of energy harvesting with focus on devices at or below the cm3 scale. The harvesting technologies discussed are based on the conversion of temperature gradients, mechanical vibrations, and radiofrequency waves. Operation principles, current state of the art, and materials issues are presented. In addition, requirements and recent developments in power conditioning for such devices are discussed. Future challenges specific to miniaturization are outlined from both the materials and device perspectives.
Scavenging vibration energy from seismically isolated bridges using an electromagnetic harvester
NASA Astrophysics Data System (ADS)
Lu, Qiuchen; Loong, Chengning; Chang, Chih-Chen; Dimitrakopoulos, Elias G.
2014-04-01
The increasing worldwide efforts in securing renewable energy sources increase incentive for civil engineers to investigate whether the kinetic energy associated with the vibration of larger-scale structures can be harvested. Such a research remains challenging and incomplete despite that hundreds of related articles have been published in the last decade. Base isolation is one of the most popular means of protecting a civil engineering structure against earthquake forces. Seismic isolation hinges on the decoupling of the structure from the shaking ground, hence protecting the structure from stress and damage during an earthquake excitation. The low stiffness isolator inserted between the structure and the ground dominates the response leading to a structural system of longer vibration period. As a consequence of this period shift, the spectral acceleration is reduced, but higher response displacements are produced. To mitigate this side effect, usually isolators are combined with the use of additional energy dissipation. In this study, the feasibility of scavenging the need-to-be dissipated energy from the isolator installed in a seismically isolated bridge using an electromagnetic (EM) energy harvester is investigated. The EM energy harvester consists of an energy harvesting circuit and a capacitor for energy storage. A mathematical model for this proposed EM energy harvester is developed and implemented on an idealized base-isolated single-degree-of-freedom system. The effect of having this EM energy harvester on the performance of this seismic isolated system is analyzed and discussed. The potential of installing such an EM energy harvester on a seismically isolated bridge is also addressed.
Fisher, Frank
ABSTRACT Vibration energy harvesting is an attractive technique for the potential powering vibrations and vibrating structures, a general requirement independent of the mechanical to electrical energy transfer mechanism is that the vibration energy harvesting device operate in resonance at the excitation
Energy Harvesting Optimization
Lavaei, Javad
those new demands. Energy harvesting derives energy from the ambient environment=harvesting is a fast-growing field that has expanded to utilize many creative sources on low frequency seismic vibrations, acoustic noises, as well as human motions
Semi-analytical solution of random response for nonlinear vibration energy harvesters
NASA Astrophysics Data System (ADS)
Jin, Xiaoling; Wang, Yong; Xu, Ming; Huang, Zhilong
2015-03-01
Due to the prominent broadband performance of nonlinear vibration energy harvester, theoretical evaluations for the mean-square response to random excitations and the associated mean output power are of great interest. By employing the generalized harmonic transformation and equivalent nonlinearization technique, established here is a semi-analytical solution of random response for nonlinear vibration energy harvesters subjected to Gaussian white noise excitation. The semi-analytical solution for stationary probability density of the system response is obtained by two iterative processes. Numerical results for a Duffing-type harvester demonstrate rapid convergence of the iterative processes and high evaluation accuracy for the mean-square response and the mean output power. Furthermore, the influence of harvesting circuit on the mechanical subsystem can be converted to modified quasi-linear damping and stiffness with energy-dependent coefficients, which is different from the traditional viewpoint on the equivalence of constant-coefficient damping and provides more comprehensive explanation on the influence of harvesting circuit.
A two-dimensional broadband vibration energy harvester using magnetoelectric transducer
Yang, Jin Wen, Yumei; Li, Ping; Yue, Xihai; Yu, Qiangmo; Bai, Xiaoling
2013-12-09
In this study, a magnetoelectric vibration energy harvester was demonstrated, which aims at addressing the limitations of the existing approaches in single dimensional operation with narrow working bandwidth. A circular cross-section cantilever rod, not a conventional thin cantilever beam, was adopted to extract vibration energy in arbitrary in-plane motion directions. The magnetic interaction not only resulted in a nonlinear motion of the rod with increased frequency bandwidth, but also contributed to a multi-mode motion to exhibit double power peaks. In energy harvesting with in-plane directions, it showed a maximum bandwidth of 4.4?Hz and power of 0.59?mW, with acceleration of 0.6?g (with g?=?9.8?m?s{sup ?2})
An evaluation on low-level vibration energy harvesting using piezoelectret foam
NASA Astrophysics Data System (ADS)
Anton, S. R.; Farinholt, K. M.
2012-04-01
Energy harvesting technology is critical in the development of self-powered electronic devices. Over the past few decades, several transduction mechanisms have been investigated for harvesting various forms of ambient energy. This paper provides an investigation of a novel transducer material for vibration energy harvesting; piezoelectret foam. Piezoelectrets are cellular ferroelectret foams, which are thin, flexible polymeric materials that exhibit piezoelectric properties. The basic operational principle behind cellular ferroelectrets involves the deformation of internally charged voids in the polymer, which can be represented as macroscopic dipoles, resulting in a potential developed across the material. Both the mechanical and electromechanical properties of this material are investigated in this work. Mechanical testing is performed using traditional tensile testing techniques to obtain experimental measures of the stiffness and strength of the materials. Electromechanical testing is performed in order to establish a relationship between input mechanical energy and output electrical energy by dynamically measuring the piezoelectric constant, d33. Additionally, the properties of ferroelectret foams are compared to those of polyvinylidene fluoride (PVDF), a conventional polymer-based piezoelectric material whose crystalline phase exhibits piezoelectricity through dipole orientation. Finally, the feasibility of vibration energy harvesting using piezoelectret materials is investigated.
Synergistic use of smart materials for vibration-based energy harvesting
NASA Astrophysics Data System (ADS)
Silva, L. L.; Oliveira, S. A.; Pacheco, P. M. C. L.; Savi, M. A.
2015-11-01
Vibration-based energy harvesting is an approach where available mechanical vibration energy is converted into electrical energy that can be employed for different purposes. This paper deals with the synergistic use of smart materials for energy harvesting purposes. In essence, piezoelectric and shape memory alloys are combined to build an energy harvesting system. The combined effect of these materials can increase the system performance and reduce some limitations. The possibility to control the mechanical stiffness under vibration by a shape memory alloy (SMA) element can provide the ability to tune resonant frequencies in order to increase the output power. The analysis is developed considering a one-degree of freedom mechanical system where the restitution force is provided by an SMA element. The electro-mechanical coupling is provided by a piezoelectric element. Linear piezoelectric constitutive equation is employed together with the Brinson's model for SMA element. Numerical simulations are carried out showing different responses of the system indicating that the inclusion of the SMA element can be used to extend the operational range of the system.
NASA Astrophysics Data System (ADS)
Haroun, Ahmed; Yamada, Ichiro; Warisawa, Shin`ichi
2015-08-01
This paper presents study of an electromagnetic vibration energy harvesting configuration that can work effectively at low frequencies. Unlike the conventional form of vibration energy harvesters in which the mass is directly connected to a vibrating frame with spring suspension, in the proposed configuration a permanent magnet mass is allowed to move freely within a certain distance inside a frame-carrying coil and make impacts with spring end stops. The free motion distance allows matching lower vibration frequencies with an increase in the relative amplitude at resonance. Hence, significant power could be generated at low frequencies. A nonlinear mathematical model including impact and electromagnetic induction is derived. Study of the dynamic behaviour and investigation of the system performance is carried out with the aid of case study simulation. The proposed harvester shows a unique dynamic behaviour in which different ways of response of the internal relative oscillation appear over the range of input frequencies. A mathematical condition for the response type at which the higher relative amplitude appears is derived, followed by an investigation of the system resonant frequency and relative amplitude. The resonant frequency shows a dependency on the free motion distance as well as the utilized mass and spring stiffness. Simulation and experimental comparisons are carried out between the proposed harvester and similar conventional one tuned at the same input frequency. The power generated by the proposed harvesting configuration can reach more than 12 times at 11 Hz in the simulation case and about 10 times at 10 Hz in the experimental case. Simulation comparison also shows that this power magnification increases by matching lower frequencies which emphasize the advantages of the proposed configuration for low frequency operation.
Gao, Xiaotong; Shih, Wei-Heng; Shih, Wan Y
2010-12-01
We have examined a piezoelectric unimorph cantilever (PUC) with unequal piezoelectric and nonpiezoelectric lengths for vibration energy harvesting theoretically by extending the analysis of a PUC with equal piezoelectric and nonpiezoelectric lengths. The theoretical approach was validated by experiments. A case study showed that for a fixed vibration frequency, the maximum open-circuit induced voltage which was important for charge storage for later use occurred with a PUC that had a nonpiezoelectric-to-piezoelectric length ratio greater than unity, whereas the maximum power when the PUC was connected to a resistor for immediate power consumption occurred at a unity nonpiezoelectric-to-piezoelectric length ratio. PMID:21200444
NASA Astrophysics Data System (ADS)
Ung, Chandarin; Moss, Scott D.; Chiu, Wing K.; Payne, Owen R.; Vandewater, Luke A.; Galea, Steve C.
2015-04-01
The dominant vibration frequencies exhibited by heavy haul railcars (operating in remote regions of Western Australia) are found to be 5.8 Hz and 14.6 Hz for loaded and unloaded trips respectively. This paper describes the in-service demonstration of two electromagnetic vibration energy harvesting technologies designed to generated power from these railcar vibrations: (i) a coupled two-degree of freedom (2-DoF) device capable of capturing both dominant frequencies of the railcar and (ii) a hybrid rotary-translational harvester device based on a magnetic sphere capable of harvesting from ? 6 Hz. The two devices were laboratory tested prior to mounting on a heavy railcar for in-service demonstration. Within the laboratory the coupled 2-DoF device was found to produce a maximum peak output power of 350 mW from 0.4 g root-mean-square (rms) acceleration at 15 Hz and 230 mW from 6 Hz. The hybrid rotary-translational device based on an oscillating magnetic sphere can produce ?138 mW from host vibration of 0.4 g rms at 5.4 Hz. This paper will discuss and compare the performance of the two prototypes, both within the laboratory and during the in-service demonstration on a heavy heal railcar.
Two-dimensional concentrated-stress low-frequency piezoelectric vibration energy harvesters
NASA Astrophysics Data System (ADS)
Sharpes, Nathan; Abdelkefi, Abdessattar; Priya, Shashank
2015-08-01
Vibration-based energy harvesters using piezoelectric materials have long made use of the cantilever beam structure. Surmounting the deficiencies in one-dimensional cantilever-based energy harvesters has been a major focus in the literature. In this work, we demonstrate a strategy of using two-dimensional beam shapes to harvest energy from low frequency excitations. A characteristic Zigzag-shaped beam is created to compare against the two proposed two-dimensional beam shapes, all of which occupy a 25.4 × 25.4 mm2 area. In addition to maintaining the low-resonance bending frequency, the proposed beam shapes are designed with the goal of realizing a concentrated stress structure, whereby stress in the beam is concentrated in a single area where a piezoelectric layer may be placed, rather than being distributed throughout the beam. It is shown analytically, numerically, and experimentally that one of the proposed harvesters is able to provide significant increase in power production, when the base acceleration is set equal to 0.1 g, with only a minimal change in the resonant frequency compared to the current state-of-the-art Zigzag shape. This is accomplished by eliminating torsional effects, producing a more pure bending motion that is necessary for high electromechanical coupling. In addition, the proposed harvesters have a large effective beam tip whereby large tip mass may be placed while retaining a low-profile, resulting in a low volume harvester and subsequently large power density.
NASA Astrophysics Data System (ADS)
Betts, David N.; Bowen, Christopher R.; Inman, Daniel J.; Weaver, Paul M.; Kim, H. A.
2014-04-01
The need for reduced power requirements for small electronic components, such as wireless sensor networks, has prompted interest in recent years for energy harvesting technologies capable of capturing energy from broadband ambient vibrations. Encouraging results have been reported for an arrangement of piezoelectric layers attached to carbon fiber / epoxy laminates which possess bistability by virtue of their specific asymmetric stacking sequence. The inherent bistability of the underlying structure is exploited for energy harvesting since a transition from one stable configuration to another, or `snap-through', is used to repeatedly strain the surface-bonded piezoelectric and generate electrical energy. Existing studies, both experimental and modelling, have been limited to simple geometric laminate shapes, restricting the scope for improved energy harvesting performance by limiting the number of design variables. In this paper we present an analytical model to predict the static shapes of laminates of any desired profile, validated experimentally using a digital image correlation system. Good accuracy in terms of out-of-plane displacements (5-7%) are shown in line with existing square modelling results. The static model is then mapped to a dynamics model and used to compare results against an experimental study of the harvesting performance of an example arbitrary geometry piezoelectric-laminate energy harvester.
Low-frequency and wideband vibration energy harvester with flexible frame and interdigital structure
NASA Astrophysics Data System (ADS)
Li, Pengwei; Liu, Ying; Wang, Yanfen; Luo, Cuixian; Li, Gang; Hu, Jie; Liu, Wei; Zhang, Wendong
2015-04-01
As an alternative to traditional cantilever beam structures and their evolutions, a flexible beam based, interdigital structure, vibration energy harvester has been presented and investigated. The proposed interdigital-shaped oscillator consists of a rectangular flexible frame and series of cantilever beams interdigitally bonded to it. In order to achieve low frequency and wide-bandwidth harvesting, Young's modulus of materials, frame size and the amount of the cantilevers have been studied systematically. The measured frequency responses of the designed device (PDMS frame, quintuple piezoelectric cantilever beams) show a 460% increase in bandwidth below 80Hz. When excited at an acceleration of 1.0 g, the energy harvester achieves to a maximum open-circuit voltage of 65V, and the maximum output power 4.5 mW.
A resonant electromagnetic vibration energy harvester for intelligent wireless sensor systems
Qiu, Jing Wen, Yumei; Li, Ping; Liu, Xin; Chen, Hengjia; Yang, Jin
2015-05-07
Vibration energy harvesting is now receiving more interest as a means for powering intelligent wireless sensor systems. In this paper, a resonant electromagnetic vibration energy harvester (VEH) employing double cantilever to convert low-frequency vibration energy into electrical energy is presented. The VEH is made up of two cantilever beams, a coil, and magnetic circuits. The electric output performances of the proposed electromagnetic VEH have been investigated. With the enhancement of turns number N, the optimum peak power of electromagnetic VEH increases sharply and the resonance frequency deceases gradually. When the vibration acceleration is 0.5?g, we obtain the optimum output voltage and power of 9.04?V and 50.8 mW at frequency of 14.9?Hz, respectively. In a word, the prototype device was successfully developed and the experimental results exhibit a great enhancement in the output power and bandwidth compared with other traditional electromagnetic VEHs. Remarkably, the proposed resonant electromagnetic VEH have great potential for applying in intelligent wireless sensor systems.
NASA Astrophysics Data System (ADS)
Muthalif, Asan G. A.; Nordin, N. H. Diyana
2015-03-01
Harvesting energy from the surroundings has become a new trend in saving our environment. Among the established ones are solar panels, wind turbines and hydroelectric generators which have successfully grown in meeting the world's energy demand. However, for low powered electronic devices; especially when being placed in a remote area, micro scale energy harvesting is preferable. One of the popular methods is via vibration energy scavenging which converts mechanical energy (from vibration) to electrical energy by the effect of coupling between mechanical variables and electric or magnetic fields. As the voltage generated greatly depends on the geometry and size of the piezoelectric material, there is a need to define an optimum shape and configuration of the piezoelectric energy scavenger. In this research, mathematical derivations for unimorph piezoelectric energy harvester are presented. Simulation is done using MATLAB and COMSOL Multiphysics software to study the effect of varying the length and shape of the beam to the generated voltage. Experimental results comparing triangular and rectangular shaped piezoelectric beam are also presented.
Chun, Inwoo; Lee, Hyun-Woo; Kwon, Kwang-Ho
2014-12-01
Limited energy sources of ubiquitous sensor networks (USNs) such as fuel cells and batteries have grave drawbacks such as the need for replacements and re-charging owing to their short durability and environmental pollution. Energy harvesting which is converting environmental mechanical vibration into electrical energy has been researched with some piezoelectric materials and various cantilever designs to increase the efficiency of energy-harvesting devices. In this study, we focused on an energy-harvesting cantilever with a broadband vibration frequency. We fabricated a lead zirconate titanate (PZT) cantilever array with various Si proof masses on small beams (5.5 mm x 0.5 mm x 0.5 mm). We obtained broadband resonant frequencies ranging between 127 Hz and 136 Hz using a micro electro-mechanical system (MEMS) process. In order to obtain broadband resonant characteristics, the cantilever array was comprised of six cantilevers with different resonant frequencies. We obtained an output power of about 2.461 ?W at an acceleration of 0.23 g and a resistance of 4 k?. The measured bandwidth of the resonant frequency was approximately 9 Hz (127-136 Hz), which is about six times wider than the bandwidth of a single cantilever. PMID:25971046
NASA Astrophysics Data System (ADS)
Galchev, Tzeno; McCullagh, James; Peterson, Rebecca L.; Najafi, Khalil; Mortazawi, Amir
2011-04-01
To power distributed wireless sensor networks on bridges, traditional power cables or battery replacement are excessively expensive or infeasible. This project develops two power harvesting technologies. First, a novel parametric frequency-increased generator (PFIG) is developed. The fabricated PFIG harvests the non-periodic and unprecedentedly low frequency (DC to 30 Hz) and low acceleration (0.55-9.8 m/s2) mechanical energy available on bridges with an average power > 2 ?W. Prototype power conversion and storage electronics were designed and the harvester system was used to charge a capacitor from arbitrary bridge-like vibrations. Second, an RF scavenger operating at medium and shortwave frequencies has been designed and tested. Power scavenging at MHz frequencies allows for lower antenna directivities, reducing sensitivity to antenna positioning. Furthermore, ambient RF signals at these frequencies have higher power levels away from cities and residential areas compared to the UHF and SHF bands utilized for cellular communication systems. An RF power scavenger operating at 1 MHz along with power management and storage circuitry has been demonstrated. It powers a LED at a distance of 10 km from AM radio stations.
Global Nonlinear Analysis of Piezoelectric Energy Harvesting from Ambient and Aeroelastic Vibrations
NASA Astrophysics Data System (ADS)
Abdelkefi, Abdessattar
Converting vibrations to a usable form of energy has been the topic of many recent investigations. The ultimate goal is to convert ambient or aeroelastic vibrations to operate low-power consumption devices, such as microelectromechanical systems, heath monitoring sensors, wireless sensors or replacing small batteries that have a finite life span or would require hard and expensive maintenance. The transduction mechanisms used for transforming vibrations to electric power include: electromagnetic, electrostatic, and piezoelectric mechanisms. Because it can be used to harvest energy over a wide range of frequencies and because of its ease of application, the piezoelectric option has attracted significant interest. In this work, we investigate the performance of different types of piezoelectric energy harvesters. The objective is to design and enhance the performance of these harvesters. To this end, distributed-parameter and phenomenological models of these harvesters are developed. Global analysis of these models is then performed using modern methods of nonlinear dynamics. In the first part of this Dissertation, global nonlinear distributed-parameter models for piezoelectric energy harvesters under direct and parametric excitations are developed. The method of multiple scales is then used to derive nonlinear forms of the governing equations and associated boundary conditions, which are used to evaluate their performance and determine the effects of the nonlinear piezoelectric coefficients on their behavior in terms of softening or hardening. In the second part, we assess the influence of the linear and nonlinear parameters on the dynamic behavior of a wing-based piezoaeroelastic energy harvester. The system is composed of a rigid airfoil that is constrained to pitch and plunge and supported by linear and nonlinear torsional and flexural springs with a piezoelectric coupling attached to the plunge degree of freedom. Linear analysis is performed to determine the effects of the linear spring coefficients and electrical load resistance on the flutter speed. Then, the normal form of the Hopf bifurcation ( utter) is derived to characterize the type of instability and determine the effects of the aerodynamic nonlinearities and the nonlinear coefficients of the springs on the system's stability near the bifurcation. This is useful to characterize the effects of different parameters on the system's output and ensure that subcritical or "catastrophic" bifurcation does not take place. Both linear and nonlinear analyses are then used to design and enhance the performance of these harvesters. In the last part, the concept of energy harvesting from vortex-induced vibrations of a circular cylinder is investigated. The power levels that can be generated from these vibrations and the variations of these levels with the freestream velocity are determined. A mathematical model that accounts for the coupled lift force, cylinder motion and generated voltage is presented. Linear analysis of the electromechanical model is performed to determine the effects of the electrical load resistance on the natural frequency of the rigid cylinder and the onset of the synchronization region. The impacts of the nonlinearities on the cylinder's response and energy harvesting are then investigated.
Multi-modal vibration based MEMS energy harvesters for ultra-low power wireless functional nodes
NASA Astrophysics Data System (ADS)
Iannacci, J.; Gottardi, M.; Serra, E.; Di Criscienzo, R.; Borrielli, A.; Bonaldi, M.
2013-05-01
The aim of this contribution is to report and discuss a preliminary study and rough optimization of a novel concept of MEMS device for vibration energy harvesting, based on a multi-modal dynamic behavior. The circular-shaped device features Four-Leaf Clover-like (FLC) double spring-mass cascaded systems, kept constrained to the surrounding frame by means of four straight beams. The combination of flexural bending behavior of the slender beams plus deformable parts of the petals enable to populate the desired vibration frequency range with a number of resonant modes, and improve the energy conversion capability of the micro-transducer. The harvester device, conceived for piezoelectric mechanical into electric energy conversion, is intended to sense environmental vibrations and, thereby, its geometry is optimized to have a large concentration of resonant modes in a frequency range below 5-10 kHz. The results of FEM (Finite Element Method) based analysis performed in ANSYSTM Workbench are reported, both concerning modal and harmonic response, providing important indications related to the device geometry optimization. The analysis reported in this work is limited to the sole mechanical modeling of the proposed MEMS harvester device concept. Future developments of the study will encompass the inclusion of piezoelectric conversion in the FEM simulations, in order to have indications of the actual power levels achievable with the proposed harvester concept. Furthermore, the results of the FEM studies here discussed, will be validated against experimental data, as soon as the MEMS resonator specimens, currently under fabrication, are ready for testing.
Study of the Ambient Vibration Energy Harvesting Based on Piezoelectric Effect
NASA Astrophysics Data System (ADS)
Si, Hongyu; Dong, Jinlu; Chen, Lei; Sun, Laizhi; Zhang, Xiaodong; Gao, Mintian
2014-01-01
The resonance between piezoelectric vibrator and the vibration source is the key to maximize the ambient vibration energy harvesting by using piezoelectric generator. In this paper, the factors that influence the output power of a single piezoelectric vibrator are analyzed. The effect of geometry size (length, thickness, width of piezoelectric chip and thickness of metal shim) of a single cantilever piezoelectric vibrator to the output power is analyzed and simulated with the help of MATLAB (matrix laboratory). The curves that output power varies with geometry size are obtained when the displacement and load at the free end are constant. Then the paper points out multi-resonant frequency piezoelectric power generation, including cantilever multi-resonant frequency piezoelectric power generation and disc type multi-resonant frequency piezoelectric generation. Multi-resonant frequency of cantilever piezoelectric power generation can be realized by placing different quality mass at the free end, while disc type multi-resonant frequency piezoelectric generation can be realized through series and parallel connection of piezoelectric vibrator.
NASA Astrophysics Data System (ADS)
Hobeck, J. D.; Inman, D. J.
2014-11-01
Extensive research has been done on the topics of both turbulence-induced vibration and vibration based energy harvesting; however, little effort has been put into bringing these two topics together. Preliminary experimental studies have shown that piezoelectric structures excited by turbulent flow can produce significant amounts of useful power. This research could serve to benefit applications such as powering remote, self-sustained sensors in small rivers or air ventilation systems where turbulent fluid flow is a primary source of ambient energy. A novel solution for harvesting energy in these unpredictable fluid flow environments was explored by the authors in previous work, and a harvester prototype was developed. This prototype, called piezoelectric grass, has been the focus of many experimental studies. In this paper the authors present a theoretical analysis of the piezoelectric grass harvester modeled as a single unimorph cantilever beam exposed to turbulent cross-flow. This distributed parameter model was developed using a combination of both analytical and statistical techniques. The analytical portion uses a Rayleigh-Ritz approximation method to describe the beam dynamics, and utilizes piezoelectric constitutive relationships to define the electromechanical coupling effects. The statistical portion of the model defines the turbulence-induced forcing function distributed across the beam surface. The model presented in this paper was validated using results from several experimental case studies. Preliminary results show that the model agrees quite well with experimental data. A parameter optimization study was performed with the proposed model. This study demonstrated how a new harvester could be designed to achieve maximum power output in a given turbulent fluid flow environment.
A vibration-based MEMS piezoelectric energy harvester and power conditioning circuit.
Yu, Hua; Zhou, Jielin; Deng, Licheng; Wen, Zhiyu
2014-01-01
This paper presents a micro-electro-mechanical system (MEMS) piezoelectric power generator array for vibration energy harvesting. A complete design flow of the vibration-based energy harvester using the finite element method (FEM) is proposed. The modal analysis is selected to calculate the resonant frequency of the harvester, and harmonic analysis is performed to investigate the influence of the geometric parameters on the output voltage. Based on simulation results, a MEMS Pb(Zr,Ti)O3 (PZT) cantilever array with an integrated large Si proof mass is designed and fabricated to improve output voltage and power. Test results show that the fabricated generator, with five cantilever beams (with unit dimensions of about 3 × 2.4 × 0.05 mm3) and an individual integrated Si mass dimension of about 8 × 12.4 × 0.5 mm3, produces a output power of 66.75 ?W, or a power density of 5.19 ?W?mm-3?g-2 with an optimal resistive load of 220 k? from 5 m/s2 vibration acceleration at its resonant frequency of 234.5 Hz. In view of high internal impedance characteristic of the PZT generator, an efficient autonomous power conditioning circuit, with the function of impedance matching, energy storage and voltage regulation, is then presented, finding that the efficiency of the energy storage is greatly improved and up to 64.95%. The proposed self-supplied energy generator with power conditioning circuit could provide a very promising complete power supply solution for wireless sensor node loads. PMID:24556670
Kim, Moonkeun; Lee, Sang-Kyun; Ham, Yong-Hyun; Yang, Yil Suk; Kwon, Jong-Kee; Kwon, Kwang-Ho
2012-08-01
We designed and fabricated a bimorph cantilever array for sustainable power with an integrated Cu proof mass to obtain additional power and current. We fabricated a cantilever system using single-crystal piezoelectric material and compared the calculations for single and arrayed cantilevers to those obtained experimentally. The vibration energy harvester had resonant frequencies of 60.4 and 63.2 Hz for short and open circuits, respectively. The damping ratio and quality factor of the cantilever device were 0.012 and 41.66, respectively. The resonant frequency at maximum average power was 60.8 Hz. The current and highest average power of the harvester array were found to be 0.728 mA and 1.61 mW, respectively. The sustainable maximum power was obtained after slightly shifting the short-circuit frequency. In order to improve the current and power using an array of cantilevers, we also performed energy conversion experiments. PMID:22962737
Hu, Junhui; Jong, Januar; Zhao, Chunsheng
2010-01-01
To increase the vibration energy-harvesting capability of the piezoelectric generator based on a cantilever beam, we have proposed a piezoelectric generator that not only uses the strain change of piezoelectric components bonded on a cantilever beam, but also employs the weights at the tip of the cantilever beam to hit piezoelectric components located on the 2 sides of weights. A prototype of the piezoelectric generator has been fabricated and its characteristics have been measured and analyzed. The experimental results show that the piezoelectric components operating in the hit mode can substantially enhance the energy harvesting of the piezoelectric generator on a cantilever beam. Two methods are used and compared in the management of rectified output voltages from different groups of piezoelectric components. In one of them, the DC voltages from rectifiers are connected in series, and then the total DC voltage is applied to a capacitor. In another connection, the DC voltage from each group is applied to different capacitors. It is found that 22.3% of the harvested energy is wasted due to the series connection. The total output electric energy of our piezoelectric generator at nonresonance could be up to 43 nJ for one vibration excitation applied by spring, with initial vibration amplitude (0-p) of 18 mm and frequency of 18.5 Hz, when the rectified voltages from different groups of piezoelectric components are connected to their individual capacitors. In addition, the motion and impact of the weights at the tip of the cantilever beam are theoretically analyzed, which well explains the experimental phenomena and suggests the measures to improve the generator. PMID:20178904
Topology optimization and fabrication of low frequency vibration energy harvesting microdevices
NASA Astrophysics Data System (ADS)
Deng, Jiadong; Rorschach, Katherine; Baker, Evan; Sun, Cheng; Chen, Wei
2015-02-01
Topological design of miniaturized resonating structures capable of harvesting electrical energy from low frequency environmental mechanical vibrations encounters a particular physical challenge, due to the conflicting design requirements: low resonating frequency and miniaturization. In this paper structural static stiffness to resist undesired lateral deformation is included into the objective function, to prevent the structure from degenerating and forcing the solution to be manufacturable. The rational approximation of material properties interpolation scheme is introduced to deal with the problems of local vibration and instability of the low density area induced by the design dependent body forces. Both density and level set based topology optimization (TO) methods are investigated in their parameterization, sensitivity analysis, and applicability for low frequency energy harvester TO problems. Continuum based variation formulations for sensitivity analysis and the material derivative based shape sensitivity analysis are presented for the density method and the level set method, respectively; and their similarities and differences are highlighted. An external damper is introduced to simulate the energy output of the resonator due to electrical damping and the Rayleigh proportional damping is used for mechanical damping. Optimization results for different scenarios are tested to illustrate the influences of dynamic and static loads. To demonstrate manufacturability, the designs are built to scale using a 3D microfabrication method and assembled into vibration energy harvester prototypes. The fabricated devices based on the optimal results from using different TO techniques are tested and compared with the simulation results. The structures obtained by the level set based TO method require less post-processing before fabrication and the structures obtained by the density based TO method have resonating frequency as low as 100 Hz. The electrical voltage response in the experiment matches the trend of the simulation data.
NASA Astrophysics Data System (ADS)
Ye, Zhitong; Duan, Zhiyong; Takahata, Kenichi; Su, Yufeng
2015-01-01
In this paper, the force analysis and output performance of the micro-vibration energy harvester are elaborated. The force of the floating magnet in the magnetic field of the lifting magnet is firstly analyzed. Using COMSOL™, the change of magnetic force exerted on the floating magnet versus the vertical distance and the horizontal eccentric distance is obtained for different lifting magnets of a cylinder, a ring and an inner cylinder plus an outer ring, respectively. When the distance between the lifting and floating magnets ranges from 7.3 to 8.1 mm, the change rate of the magnetic force versus the vertical distance for the inner cylinder plus outer ring structure is the smallest, whose value is 619 µN/mm. In other words, if the inner cylinder plus outer ring structure is used as the lifting magnet, the vibration space of the floating magnet is the largest, which is 8 and 7.6 % larger than the cylinder and ring lifting magnets, respectively. The horizontal restoring forces of the three structures are substantially equal to each other at the horizontal eccentric distance of 4 mm, which is around 860 µN. Then the equilibrium position change of the floating magnet is discussed when the energy harvester is in an inclined position. Finally, by the analysis of the vibration model, the output performances of the energy harvester are comparatively calculated under the vertical and inclined positions. At the natural frequency of 6.93 Hz, the maximum power of 66.7 µW is generated.
NASA Astrophysics Data System (ADS)
Ye, Zhitong; Duan, Zhiyong; Takahata, Kenichi; Su, Yufeng
2014-08-01
In this paper, the force analysis and output performance of the micro-vibration energy harvester are elaborated. The force of the floating magnet in the magnetic field of the lifting magnet is firstly analyzed. Using COMSOL™, the change of magnetic force exerted on the floating magnet versus the vertical distance and the horizontal eccentric distance is obtained for different lifting magnets of a cylinder, a ring and an inner cylinder plus an outer ring, respectively. When the distance between the lifting and floating magnets ranges from 7.3 to 8.1 mm, the change rate of the magnetic force versus the vertical distance for the inner cylinder plus outer ring structure is the smallest, whose value is 619 µN/mm. In other words, if the inner cylinder plus outer ring structure is used as the lifting magnet, the vibration space of the floating magnet is the largest, which is 8 and 7.6 % larger than the cylinder and ring lifting magnets, respectively. The horizontal restoring forces of the three structures are substantially equal to each other at the horizontal eccentric distance of 4 mm, which is around 860 µN. Then the equilibrium position change of the floating magnet is discussed when the energy harvester is in an inclined position. Finally, by the analysis of the vibration model, the output performances of the energy harvester are comparatively calculated under the vertical and inclined positions. At the natural frequency of 6.93 Hz, the maximum power of 66.7 µW is generated.
Harvesting energy from the vibration of a passing train using a single-degree-of-freedom oscillator
NASA Astrophysics Data System (ADS)
Gatti, G.; Brennan, M. J.; Tehrani, M. G.; Thompson, D. J.
2016-01-01
With the advent of wireless sensors, there has been an increasing amount of research in the area of energy harvesting, particularly from vibration, to power these devices. An interesting application is the possibility of harvesting energy from the track-side vibration due to a passing train, as this energy could be used to power remote sensors mounted on the track for strutural health monitoring, for example. This paper describes a fundamental study to determine how much energy could be harvested from a passing train. Using a time history of vertical vibration measured on a sleeper, the optimum mechanical parameters of a linear energy harvesting device are determined. Numerical and analytical investigations are both carried out. It is found that the optimum amount of energy harvested per unit mass is proportional to the product of the square of the input acceleration amplitude and the square of the input duration. For the specific case studied, it was found that the maximum energy that could be harvested per unit mass of the oscillator is about 0.25 J/kg at a frequency of about 17 Hz. The damping ratio for the optimum harvester was found to be about 0.0045, and the corresponding amplitude of the relative displacement of the mass is approximately 5 mm.
NASA Astrophysics Data System (ADS)
Mori, Kotaro; Horibe, Tadashi; Ishikawa, Shigekazu; Shindo, Yasuhide; Narita, Fumio
2015-12-01
This work deals with the dynamic bending and energy harvesting characteristics of giant magnetostrictive cantilevers with resonant tuning both numerically and experimentally. The giant magnetostrictive cantilever is fabricated using a thin Terfenol-D layer, SUS layer, movable proof mass, etc, and, is designed to automatically adjust its own resonant frequency to match the external vibration frequency in real time. Three-dimensional finite element analysis was conducted, and the resonant frequency, induced voltage and stress in the magnetostrictive cantilevers were predicted. The resonant frequency and induced voltage were also measured, and comparison was made between simulation and experiment. The time-varying behavior and self-tuning ability are discussed in detail.
NASA Astrophysics Data System (ADS)
Li, Peng; Zhang, Chongxiao; Kim, Junyoung; Yu, Liangyao; Zuo, Lei
2014-04-01
Regenerative semi-active suspensions can capture the previously dissipated vibration energy and convert it to usable electrical energy for powering on-board electronic devices, while achieve both the better ride comfort and improved road handling performance at the same time when certain control is applied. To achieve this objective, the power electronics interface circuit connecting the energy harvester and the electrical loads, which can perform simultaneous vibration control and energy harvesting function is in need. This paper utilized a buck-boost converter for simultaneous semi-active vibration control and energy harvesting with electromagnetic regenerative shock absorber, which utilizes a rotational generator to converter the vibration energy to electricity. It has been found that when the circuit works in discontinuous current mode (DCM), the ratio between the input voltage and current is only related to the duty cycle of the switch pulse width modulation signal. Using this property, the buck-boost converter can be used to perform semi-active vibration control by controlling the load connected between the terminals of the generator in the electromagnetic shock absorber. While performing the vibration control, the circuit always draw current from the shock absorber and the suspension remain dissipative, and the shock absorber takes no additional energy to perform the vibration control. The working principle and dynamics of the circuit has been analyzed and simulations were performed to validate the concept.
Minh, Le Van; Hara, Motoaki; Yokoyama, Tsuyoshi; Nishihara, Tokihiro; Ueda, Masanori; Kuwano, Hiroki
2015-11-01
The first MgZr co-doped AlN-based vibrational energy harvester (VEH) is presented. (MgZr)AlN, which is a new class of doped AlN, provides high piezoelectricity and cost advantage. Using 13%-(MgZr)-doped AlN for micromachined VEHs, maximum output power of 1.3 ?W was achieved with a Q-factor of 400 when resonant frequency, vibration acceleration, load resistance were 792 Hz, 8 m/s(2), and 1.1 M?, respectively. Normalized power density was 8.1 kW.g(-2).m(-3). This was one of the highest values among the currently available piezoelectric VEHs. PMID:26559628
NASA Astrophysics Data System (ADS)
Shen, Li; Wu, Jiu Hui; Zhang, Siwen; Liu, Zhangyi; Li, Jing
2015-01-01
A low-frequency vibration energy generator has been proposed by using a locally resonant phononic crystal plate which has spiral beams connecting the scatterers and the matrix. Finite element analysis shows that at the flat bands frequencies of the phononic crystal, locally resonant leads to the spiral beams having strong deformations which are perpendicular to the plate. A designed structure with three PC cells arranged in the same direction was adopted for the experiments. Piezoelectric patches were adhered on the end of the spiral beams and then the collected vibration energy could be converted into electric energy. The maximum single-channel output voltage which reached as much as 13 V was obtained at the first flat band frequency 29.2 Hz in the experiment. Meanwhile, in the low-frequency range of 0-500 Hz, it showed that the piezoelectric transformation could be conducted at a dozen of resonant frequencies. Furthermore, through modulating the structure parameters, this phononic crystal has the potential to realize broad-distributed vibration energy harvesting.
NASA Astrophysics Data System (ADS)
Takeya, Kouichi; Sasaki, Eiichi; Kobayashi, Yusuke
2016-01-01
A bridge vibration energy harvester has been proposed in this paper using a tuned dual-mass damper system, named hereafter Tuned Mass Generator (TMG). A linear electromagnetic transducer has been applied to harvest and make use of the unused reserve of energy the aforementioned damper system absorbs. The benefits of using dual-mass systems over single-mass systems for power generation have been clarified according to the theory of vibrations. TMG parameters have been determined considering multi-domain parameters, and TMG has been tuned using a newly proposed parameter design method. Theoretical analysis results have shown that for effective energy harvesting, it is essential that TMG has robustness against uncertainties in bridge vibrations and tuning errors, and the proposed parameter design method for TMG has demonstrated this feature.
NASA Astrophysics Data System (ADS)
Palagummi, S.; Yuan, F. G.
2015-04-01
A detailed analysis of a mono-stable vertical diamagnetic levitation (VDL) system for optimal vibration energy harvesting is presented. Initial studies showed that simple analytical techniques such as the dipole model and the image method provide useful guideline for understanding the potential of a diamagnetic levitation system, however, it is discussed here that the more accurate semi-analytical techniques such as the thin coil model and the discrete volume method are needed for quantitative optimization and design of the VDL system. With the semi-analytical techniques, the influence of the cylindrical geometry of the floating magnet, the lifting magnet and the diamagnetic plate are parametrically studied to assess their effects on the levitation gap, size of the system and the natural frequency. For efficient vibration energy harvesting using the VDL system, ways to mitigate eddy current damping and a coil geometry for transduction are critically discussed. With the optimized parameters, an experimental system is realized which showed a hardening type nonlinearity. The results show an overall efficiency of 1.54 percent, a root mean square (rms) power output of 1.72 ?W when excited at a peak acceleration of 0.081 m/s2 and at a frequency of 2.1 Hz.
NASA Astrophysics Data System (ADS)
Wang, Peihong; Du, Hejun
2015-07-01
Zinc oxide (ZnO) thin film piezoelectric microelectromechanical systems (MEMS) based vibration energy harvesters with two different designs are presented. These harvesters consist of a silicon cantilever, a silicon proof mass, and a ZnO piezoelectric layer. Design I has a large ZnO piezoelectric element and Design II has two smaller and equally sized ZnO piezoelectric elements; however, the total area of ZnO thin film in two designs is equal. The ZnO thin film is deposited by means of radio-frequency magnetron sputtering method and is characterized by means of XRD and SEM techniques. These ZnO energy harvesters are fabricated by using MEMS micromachining. The natural frequencies of the fabricated ZnO energy harvesters are simulated and tested. The test results show that these two energy harvesters with different designs have almost the same natural frequency. Then, the output performance of different ZnO energy harvesters is tested in detail. The effects of series connection and parallel connection of two ZnO elements on the load voltage and power are also analyzed. The experimental results show that the energy harvester with two ZnO piezoelectric elements in parallel connection in Design II has higher load voltage and higher load power than the fabricated energy harvesters with other designs. Its load voltage is 2.06 V under load resistance of 1 M? and its maximal load power is 1.25 ?W under load resistance of 0.6 M?, when it is excited by an external vibration with frequency of 1300.1 Hz and acceleration of 10 m/s2. By contrast, the load voltage of the energy harvester of Design I is 1.77 V under 1 M? resistance and its maximal load power is 0.98 ?W under 0.38 M? load resistance when it is excited by the same vibration.
Wang, Peihong; Du, Hejun
2015-07-01
Zinc oxide (ZnO) thin film piezoelectric microelectromechanical systems (MEMS) based vibration energy harvesters with two different designs are presented. These harvesters consist of a silicon cantilever, a silicon proof mass, and a ZnO piezoelectric layer. Design I has a large ZnO piezoelectric element and Design II has two smaller and equally sized ZnO piezoelectric elements; however, the total area of ZnO thin film in two designs is equal. The ZnO thin film is deposited by means of radio-frequency magnetron sputtering method and is characterized by means of XRD and SEM techniques. These ZnO energy harvesters are fabricated by using MEMS micromachining. The natural frequencies of the fabricated ZnO energy harvesters are simulated and tested. The test results show that these two energy harvesters with different designs have almost the same natural frequency. Then, the output performance of different ZnO energy harvesters is tested in detail. The effects of series connection and parallel connection of two ZnO elements on the load voltage and power are also analyzed. The experimental results show that the energy harvester with two ZnO piezoelectric elements in parallel connection in Design II has higher load voltage and higher load power than the fabricated energy harvesters with other designs. Its load voltage is 2.06 V under load resistance of 1 M? and its maximal load power is 1.25 ?W under load resistance of 0.6 M?, when it is excited by an external vibration with frequency of 1300.1 Hz and acceleration of 10 m/s(2). By contrast, the load voltage of the energy harvester of Design I is 1.77 V under 1 M? resistance and its maximal load power is 0.98 ?W under 0.38 M? load resistance when it is excited by the same vibration. PMID:26233403
NASA Astrophysics Data System (ADS)
Zhao, Liuxian; Conlon, Stephen C.; Semperlotti, Fabio
2015-06-01
In this paper, we present an experimental investigation on the energy harvesting performance of dynamically tailored structures based on the concept of embedded acoustic black holes (ABHs). Embedded ABHs allow tailoring the wave propagation characteristics of the host structure creating structural areas with extreme levels of energy density. Experiments are conducted on a tapered plate-like aluminum structure with multiple embedded ABH features. The dynamic response of the structure is tested via laser vibrometry in order to confirm the vibration localization and the passive wavelength sweep characteristic of ABH embedded tapers. Vibrational energy is extracted from the host structure and converted into electrical energy by using ceramic piezoelectric discs bonded on the ABHs and shunted on an external electric circuit. The energy harvesting performance is investigated both under steady state and transient excitation. The experimental results confirm that the dynamic tailoring produces a drastic increase in the harvested energy independently from the nature of the excitation input.
Sassani, Farrokh
2014-01-01
The simulation results for electromagnetic energy harvesters (EMEHs) under broad band stationary Gaussian random excitations indicate the importance of both a high transformation factor and a high mechanical quality factor to achieve favourable mean power, mean square load voltage, and output spectral density. The optimum load is different for random vibrations and for sinusoidal vibration. Reducing the total damping ratio under band-limited random excitation yields a higher mean square load voltage. Reduced bandwidth resulting from decreased mechanical damping can be compensated by increasing the electrical damping (transformation factor) leading to a higher mean square load voltage and power. Nonlinear EMEHs with a Duffing spring and with linear plus cubic damping are modeled using the method of statistical linearization. These nonlinear EMEHs exhibit approximately linear behaviour under low levels of broadband stationary Gaussian random vibration; however, at higher levels of such excitation the central (resonant) frequency of the spectral density of the output voltage shifts due to the increased nonlinear stiffness and the bandwidth broadens slightly. Nonlinear EMEHs exhibit lower maximum output voltage and central frequency of the spectral density with nonlinear damping compared to linear damping. Stronger nonlinear damping yields broader bandwidths at stable resonant frequency. PMID:24605063
From MEMS to macro-world: a micro-milling machined wideband vibration piezoelectric energy harvester
NASA Astrophysics Data System (ADS)
Iannacci, J.; Sordo, G.
2015-05-01
In this work, we discuss a novel mechanical resonator design for the realization of vibration Energy Harvester (EH) capable to deliver power levels in the mW range. The device overcomes the typical constraint of frequency narrowband operability of standard cantilevered EHs, by exploiting a circular-shaped resonator with an increased number of mechanical Degrees Of Freedom (DOFs), leading to several resonant modes in the range of vibrations of interest (i.e. multi-modal wideband EH). The device, named Four-Leaf Clover (FLC), is simulated in Ansys Worbench™, showing a significant number of resonant modes up to vibrations of around 2 kHz (modal eigenfrequencies analysis), and exhibiting levels of converted power up to a few mW at resonance (harmonic coupled-field analysis). The sole FLC mechanical structure is realized by micro-milling an Aluminum foil, while a cantilevered test structure also including PolyVinyliDene Fluoride (PVDF) film sheet is assembled in order to collect first experimental feedback on generated power levels. The first lab based tests show peak-to-peak voltages of several Volts when the cantilever is stimulated with a mechanical pulse. Further developments of this work will comprise the assembly of an FLC demonstrator with PVDF pads, and its experimental testing in order to validate the simulated results.
NASA Astrophysics Data System (ADS)
Leng, Y. G.; Gao, Y. J.; Tan, D.; Fan, S. B.; Lai, Z. H.
2015-02-01
To overcome the defect of conventional nonlinear piezoelectric cantilever vibration energy harvesters, in this paper we conceive an elastic-support model to study the performance of energy converters under two types of variable-intensity excitation conditions: filtered Gaussian noises and pink noises. When excitation intensity is insufficient, thanks to the system's variable potential function, frequent bistable transition oscillations between two wells occur in elastic-support systems, while only weak oscillations in either well could be observed in rigid-support systems. In practical applications, the structural parameters of energy harvesters are not allowed to make real-time changes. If considered remaining the magnet interval and the spring's elastic stiffness unchanged while receiving stable maximum output voltage, elastic-support systems can be made full use toward variable-intensity filtered Gaussian noises. It has been proven that elastic-support systems are capable of adapting to random excitations with variable intensity, through which maximum power output and sufficient electromechanical energy conversion of the system can be accomplished.
Modeling and design of a vibration energy harvester using the magnetic shape memory effect
NASA Astrophysics Data System (ADS)
Saren, A.; Musiienko, D.; Smith, A. R.; Tellinen, J.; Ullakko, K.
2015-09-01
In this study, a vibration energy harvester is investigated which uses a Ni-Mn-Ga sample that is mechanically strained between 130 and 300 Hz while in a constant biasing magnetic field. The crystallographic reorientation of the sample during mechanical actuation changes its magnetic properties due to the magnetic shape memory (MSM) effect. This leads to an oscillation of the magnetic flux in the yoke which generates electrical energy by inducing an alternating current within the pick-up coils. A power of 69.5 mW (with a corresponding power density of 1.37 mW mm-3 compared to the active volume of the MSM element) at 195 Hz was obtained by optimizing the biasing magnetic field, electrical resistance and electrical resonance. The optimization of the electrical resonance increased the energy generated by nearly a factor of four when compared to a circuit with no resonance. These results are strongly supported by a theoretical model and simulation which gives corresponding values with an error of approximately 20% of the experimental data. This model will be used in the design of future MSM energy harvesters and their optimization for specific frequencies and power outputs.
Modeling and Tuning for Vibration Energy Harvesting using a Piezoelectric Bimorph
NASA Astrophysics Data System (ADS)
Cao, Yongqing
With the development of wireless sensors and other devices, the need for continuous power supply with high reliability is growing ever more. The traditional battery power supply has the disadvantage of limited duration of continuous power supply capability so that replacement for new batteries has to be done regularly. This can be quite inconvenient and sometimes quite difficult especially when the sensors are located in places not easily accessible such as the inside of a machine or wild field. This situation stimulates the development of renewable power supply which can harvest energy from the environment. The use of piezoelectric materials to converting environment vibration to electrical energy is one of the alternatives of which a broad range of research has been done by many researchers, focusing on different issues. The improvement of efficiency is one of the most important issues in vibration based energy harvesting. For this purpose different methods are devised and more accurate modeling of coupled piezoelectric mechanical systems is investigated. In the current paper, the research is focused on improving voltage generation of a piezoelectric bimorph on a vibration beam, as well as the analytical modeling of the same system. Also an initial study is conducted on the characteristics of the vibration of Zinc oxide (ZnO) nanowire, which is a promising material for its coupled semiconducting and piezoelectric properties. The effect on the voltage generation by different placement of the piezoelectric bimorph on the vibrating beam is investigated. The relation between the voltage output and the curvature is derived which is used to explain the effect of placement on voltage generation. The effect of adding a lumped mass on the modal frequencies of the beam and on the curvature distribution is investigated. The increased voltage output from the piezoelectric bimorph by using appropriately selected mass is proved analytically and also verified by experiment. For the modeling of piezoelectric generator, different methods are employed to modeling the coupled dynamics of a piezoelectric bimorph on a vibrating beam as well as a simple piezoelectric bimorph cantilever. The modeling of piezoelectric bimorph as an alternative current (AC) source with internal capacitance and resistance is used to analyze a piezoelectric bimorph cantilever and to calculate the optimal external load resistance for maximal power output. The couple dynamics method based on Hamilton's Principle is applied in the modeling of the piezoelectric bimorph on a vibrating beam. Impulse response experiment shows this method has a better estimation of the experimental results than the curvature model. The coupled dynamics model is also applied to piezoelectric bimorph cantilever and the external load resistance is also determined by this to maximize the power output. The finite element equations for the piezoelectric materials in the element domain are theoretically derived. The procedure of modeling a piezoelectric on a vibrating beam is demonstrated base on the package of ANSYS. The frequency response of ZnO nanowires with different dimensions is derived analytically for ambient mediums with different damping ratios. With help from nano research lab of Dr. Yong Zhu and the student Feng Xu, an experiment is conducted which indentifies the first modal frequency of ZnO nanowires with different dimensions. The experimental modal frequencies are compared with the numerical results. The influence of the thickness of deposit on the modal frequency is also investigated by finite element modeling.
NASA Astrophysics Data System (ADS)
Payne, Owen R.; Vandewater, Luke A.; Ung, Chandarin; Moss, Scott D.
2015-04-01
In this paper, a self-powered wireless sensor node utilising ambient vibrations for power is described. The device consists of a vibration energy harvester, power management system, microcontroller, accelerometer, RF transmitter/receiver and external LED indicators. The vibration energy harvester is adapted from a previously reported hybrid rotary-translational device and uses a pair of copper coil transducers to convert the mechanical energy of a magnetic sphere into usable electricity. The device requires less than 0.8 mW of power to operate continuously in its present setup (with LED indicators off) while measuring acceleration at a sample rate of 200 Hz, with the power source providing 39.7 mW of power from 500 mg excitations at 5.5 Hz. When usable input energy is removed, the device will continue to transmit data for more than 5 minutes.
Improved design of linear electromagnetic transducers for large-scale vibration energy harvesting
NASA Astrophysics Data System (ADS)
Tang, Xiudong; Zuo, Lei; Lin, Teng; Zhang, Peisheng
2011-03-01
This paper presents the design and optimization of tubular Linear Electromagnetic Transducers (LETs) with applications to large-scale vibration energy harvesting, such as from vehicle suspensions, tall buildings or long bridges. Four types of LETs are considered and compared, namely, single-layer configuration using axial magnets, double-layer configuration using axial magnets, single-layer configuration using both axial and radial magnets, double-layer configuration using both axial and radial magnets. In order to optimize the LETs, the parameters investigated in this paper include the thickness of the magnets in axial direction and the thickness of the coils in the radial direction. Finite element method is used to analyze the axisymmetric two-dimensional magnetic fields. Both magnetic flux densities Br [T] in the radial direction and power density [W/m3] are calculated. It is found that the parameter optimization can increase the power density of LETs to 2.7 times compared with the initial design [Zuo et al, Smart Materials and Structures, v19 n4, 2010], and the double-layer configuration with both radial and axial magnets can improve the power density to 4.7 times, approaching to the energy dissipation rate of traditional oil dampers. As a case study, we investigate its application to energy-harvesting shock absorbers. For a reasonable retrofit size, the LETs with double-layer configuration and both axial and radial NdFeB magnets can provide a damping coefficient of 1138 N.s/m while harvesting 35.5 W power on the external electric load at 0.25 m/s suspension velocity. If the LET is shorten circuit, it can dissipate energy at the rate of 142.0 W, providing of a damping coefficient of 2276 N.s/m. Practical consideration of number of coil phases is also discussed.
Comparison of Five Topologies of Cantilever-based MEMS Piezoelectric Vibration Energy Harvesters
NASA Astrophysics Data System (ADS)
Jia, Y.; Seshia, A. A.
2014-11-01
In the realm of MEMS piezoelectric vibration energy harvesters, cantilever-based designs are by far the most popular. Despite being deceptively simple, the active piezoelectric area near the clamped end is able to accumulate maximum strain-generated-electrical-charge, while the free end is able to accommodate a proof mass without compromising the effective area of the piezoelectric generator since it experiences minimal strain anyway. While other contending designs do exist, this paper investigates five micro-cantilever (MC) topologies, namely: a plain MC, a tapered MC, a lined MC, a holed MC and a coupled MC, in order to assess their relative performance as an energy harvester. Although a classical straight and plain MC offers the largest active piezoelectric area, alternative MC designs can potentially offer higher average mechanical strain distribution for a given mechanical loading. Numerical simulation and experimental comparison of these 5 MCs (0.5 ? AlN on 10 ?m Si) with the same practical dimensions of 500 ?m and 2000 ?m, suggest a cantilever with a coupled subsidiary cantilever yield the best power performance, closely followed by the classical plain topology.
Reliability of vibration energy harvesters of metal-based PZT thin films
NASA Astrophysics Data System (ADS)
Tsujiura, Y.; Suwa, E.; Kurokawa, F.; Hida, H.; Kanno, I.
2014-11-01
This paper describes the reliability of piezoelectric vibration energy harvesters (PVEHs) of Pb(Zr,Ti)O3 (PZT) thin films on metal foil cantilevers. The PZT thin films were directly deposited onto the Pt-coated stainless-steel (SS430) cantilevers by rf-magnetron sputtering, and we observed their aging behavior of power generation characteristics under the resonance vibration condition for three days. During the aging measurement, there was neither fatigue failure nor degradation of dielectric properties in our PVEHs (length: 13 mm, width: 5.0 mm, thickness: 104 ?m) even under a large excitation acceleration of 25 m/s2. However, we observed clear degradation of the generated electric voltage depending on excitation acceleration. The decay rate of the output voltage was 5% from the start of the measurement at 25 m/s2. The transverse piezoelectric coefficient (e31,f) also degraded with almost the same decay rate as that of the output voltage; this indicates that the degradation of output voltage was mainly caused by that of piezoelectric properties. From the decay curves, the output powers are estimated to degrade 7% at 15 m/s2 and 36% at 25 m/s2 if we continue to excite the PVEHs for 30 years.
NASA Astrophysics Data System (ADS)
Hanumantha Rao, T. V.; Srinivasa Rao, M. S. S.; Apparao, B. V.; Satyanarayana, K.
2014-04-01
The basic purpose of a damper is to reduce the vibration and to have a better ride comfort, road handling and safety to the rider. Recent developments show that an active vibration damper can effectively work much better than a passive damper. The effectiveness and reliability can be further enhanced by using hybrid dampers, which is a combination of active and passive dampers. But the need to have energy optimization in any field need not be stressed. Consequently, novel suspension concepts are required, not only to improve the vehicle's dynamic performance, but also to see that the energy generated during vibration can be harvested by utilizing regeneration functions. Hence if a hybrid damper with energy harvesting capability be designed, it would serve both purposes. In the hybrid damper a combination of hydraulic damper to act as a passive damper and an electromagnetic (EM) damper to act as an active damper is considered. The hydraulic system has more reliability and is time tested and the EM system acts as a dynamic vibration system as well as energy harvester. In this study a hybrid EM damper is modeled, analyzed and validity is shown for frequency response functions and energy balance for its active use. It is also shown how the effectiveness of the suspension system can be enhanced by using a hybrid damper.
Zizys, Darius; Gaidys, Rimvydas; Dauksevicius, Rolanas; Ostasevicius, Vytautas; Daniulaitis, Vytautas
2015-01-01
The piezoelectric transduction mechanism is a common vibration-to-electric energy harvesting approach. Piezoelectric energy harvesters are typically mounted on a vibrating host structure, whereby alternating voltage output is generated by a dynamic strain field. A design target in this case is to match the natural frequency of the harvester to the ambient excitation frequency for the device to operate in resonance mode, thus significantly increasing vibration amplitudes and, as a result, energy output. Other fundamental vibration modes have strain nodes, where the dynamic strain field changes sign in the direction of the cantilever length. The paper reports on a dimensionless numerical transient analysis of a cantilever of a constant cross-section and an optimally-shaped cantilever with the objective to accurately predict the position of a strain node. Total effective strain produced by both cantilevers segmented at the strain node is calculated via transient analysis and compared to the strain output produced by the cantilevers segmented at strain nodes obtained from modal analysis, demonstrating a 7% increase in energy output. Theoretical results were experimentally verified by using open-circuit voltage values measured for the cantilevers segmented at optimal and suboptimal segmentation lines. PMID:26703623
Robust energy harvesting from walking vibrations by means of nonlinear cantilever beams
NASA Astrophysics Data System (ADS)
Kluger, Jocelyn M.; Sapsis, Themistoklis P.; Slocum, Alexander H.
2015-04-01
In the present work we examine how mechanical nonlinearity can be appropriately utilized to achieve strong robustness of performance in an energy harvesting setting. More specifically, for energy harvesting applications, a great challenge is the uncertain character of the excitation. The combination of this uncertainty with the narrow range of good performance for linear oscillators creates the need for more robust designs that adapt to a wider range of excitation signals. A typical application of this kind is energy harvesting from walking vibrations. Depending on the particular characteristics of the person that walks as well as on the pace of walking, the excitation signal obtains completely different forms. In the present work we study a nonlinear spring mechanism that is composed of a cantilever wrapping around a curved surface as it deflects. While for the free cantilever, the force acting on the free tip depends linearly on the tip displacement, the utilization of a contact surface with the appropriate distribution of curvature leads to essentially nonlinear dependence between the tip displacement and the acting force. The studied nonlinear mechanism has favorable mechanical properties such as low frictional losses, minimal moving parts, and a rugged design that can withstand excessive loads. Through numerical simulations we illustrate that by utilizing this essentially nonlinear element in a 2 degrees-of-freedom (DOF) system, we obtain strongly nonlinear energy transfers between the modes of the system. We illustrate that this nonlinear behavior is associated with strong robustness over three radically different excitation signals that correspond to different walking paces. To validate the strong robustness properties of the 2DOF nonlinear system, we perform a direct parameter optimization for 1DOF and 2DOF linear systems as well as for a class of 1DOF and 2DOF systems with nonlinear springs similar to that of the cubic spring that are physically realized by the cantilever-surface mechanism. The optimization results show that the 2DOF nonlinear system presents the best average performance when the excitation signals have three possible forms. Moreover, we observe that while for the linear systems the optimal performance is obtained for small values of the electromagnetic damping, for the 2DOF nonlinear system optimal performance is achieved for large values of damping. This feature is of particular importance for the system's robustness to parasitic damping.
NASA Astrophysics Data System (ADS)
Zhang, Y.; Zheng, R.; Kaizuka, T.; Su, D.; Nakano, K.; Cartmell, M. P.
2015-11-01
A model for energy harvesting from a rotating automotive tyre is suggested in which the principle of stochastic resonance is advantageously exploited. A bistable response characteristic is obtained by recourse a small harvester comprising a magnetically repellant configuration in which an instrumented cantilever beam can flip between two physical response states when suitably excited by the rotation of a car wheel into which it is fitted. The rotation of the wheel creates a periodic modulation which enables stochastic resonance to take place and as a consequence of this for energy to be harvested from road noise transmitted through the tyre. An optimised mathematical model of the system is presented based on a series of experimental tests and it is shown that a ten-fold increase in harvested energy over a comparable monostable case is feasible. The suggested application for this harvester is to provide electrical power for a tyre pressure monitoring system.
A flex-compressive-mode piezoelectric transducer for mechanical vibration/strain energy harvesting.
Li, Xiaotian; Guo, Mingsen; Dong, Shuxiang
2011-04-01
A piezoelectric transducer for harvesting energy from ambient mechanical vibrations/strains under pressure condition was developed. The proposed transducer was made of two ring-type piezoelectric stacks, one pair of bow-shaped elastic plates, and one shaft that pre-compresses them. This transducer works in flex-compressive (F-C) mode, which is different from a conventional flex-tensional (F-T) one, to transfer a transversely applied force F into an amplified longitudinal force N pressing against the two piezo-stacks via the two bowshaped elastic plates, generating a large electric voltage output via piezoelectric effect. Our experimental results show that without an electric load, an F-C mode piezo-transducer could generate a maximum electric voltage output of up to 110 Vpp, and with an electric load of 40 ??, it a maximum power output of 14.6 mW under an acceleration excitation of 1 g peak-peak at the resonance frequency of 87 Hz. PMID:21507747
Vibration energy harvesting by a Timoshenko beam model and piezoelectric transducer
NASA Astrophysics Data System (ADS)
Stoykov, S.; Litak, G.; Manoach, E.
2015-11-01
An electro-mechanical system of vibrational energy harvesting is studied. The beam is excited by external and kinematic periodic forces and damped by an electrical resistor through the coupled piezoelectric transducer. Nonlinearities are introduced by stoppers limiting the transverse displacements of the beam. The interaction between the beam and the stoppers is modeled as Winkler elastic foundation. The mechanical properties of the piezoelectric layer are taken into account and the beam is modeled as a composite structure. For the examined composite beam, the geometrically nonlinear version of the Timoshenko's beam theory is assumed. The equations of motion are derived by the principle of virtual work considering large deflections. An isogeometric approach is applied for space discretization and B-Splines are used as shape functions. Finally, the power output and the efficiency of the system due to harmonic excitations are discussed. The influence of the position of the stoppers and their length on the dynamics of the beam and consequently on the power output are analyzed and presented.
Reliability of potassium ion electret in silicon oxide for vibrational energy harvester applications
NASA Astrophysics Data System (ADS)
Misawa, Kensuke; Sugiyama, Tatsuhiko; Hashiguchi, Gen; Toshiyoshi, Hiroshi
2015-06-01
In this paper, we report on the long-term reliability of potassium ion electret included in a thermally grown silicon oxide. The electret in this work is used in a microelectromechanical systems (MEMS) energy harvester to generate electrical current from mechanical vibration. A spring-mass system similar to a comb-drive electrostatic actuator is developed by silicon micromachining, and the surface is oxidized by wet-oxidation through a potassium hydroxide bubbler, thereby including potassium atoms at a high concentration. The potassium is then electrically polarized by an applied voltage of 150 V at 650 °C for 5 min. Degradation of the stored polarization potential is monitored in a vacuum of 1 × 10-3 Pa at elevated temperatures of 350, 400, and 450 °C. The time needed to cause a -1 dB decay of the potential is used as the lifetime of the electret, and the Arrhenius extrapolation plot suggested a life time of more than 400 years at 25 °C.
A 1-mW vibration energy harvesting system for moth flight-control applications
Chang, Samuel C
2010-01-01
This thesis focuses on the approach and methodologies required to build a 1-mW energy-harvesting system for moth flight control applications. The crepuscular hawk moth Manduca sexta is the chosen test subject. This project ...
Experimental verification of a bridge-shaped, nonlinear vibration energy harvester
Gafforelli, Giacomo
This paper reports a comprehensive modeling and experimental characterization of a bridge shaped nonlinear energy harvester. A doubly clamped beam at large deflection requires stretching strain in addition to the bending ...
NASA Astrophysics Data System (ADS)
Javed, U.; Dai, H. L.; Abdelkefi, A.
2015-11-01
Modeling and comparative analysis of galloping-based hybrid piezoelectric-inductive energy harvesting systems are investigated. Both piezoelectric and electromagnetic transducers are attached to the transverse degree of freedom of the prismatic structure in order to harvest energy from two possible sources. A fully-coupled electroaeroelastic model is developed which takes into account the coupling between the generated voltage from the piezoelectric transducer, the induced current from the electromagnetic transducer, and the transverse displacement of the bluff body. A nonlinear quasi-steady approximation is employed to model the galloping force. To determine the influences of the external load resistances that are connected to the piezoelectric and electromagnetic circuits on the onset speed of galloping, a deep linear analysis is performed. It is found that the external load resistances in these two circuits have significant effects on the onset speed of galloping of the harvester with the presence of optimum values. To investigate the effects of these transduction mechanisms on the performance of the galloping energy harvester, a nonlinear analysis is performed. Using the normal form of the Hopf bifurcation, it is demonstrated that the hybrid energy harvester has a supercritical instability for different values of the external load resistances. For well-defined wind speed and external load resistance in the electromagnetic circuit, the results showed that there is a range of external load resistances in the piezoelectric circuit at which the output power generated by the electromagnetic induction is very small. On the other hand, there are two optimal load resistances at which the output power by the piezoelectric transducer is maximum. Based on a comparative study, it is demonstrated the hybrid piezoelectric-inductive energy harvester is very beneficial in terms of having two sources of energy. However, compared to the classical piezoelectric and electromagnetic energy harvesters, the results show that, considering a hybrid energy harvester leads to an increase in the onset speed of galloping and a decrease in the levels of the harvested power in both the piezoelectric and electromagnetic circuits which is explained by the additional resistive shunt damping effects in the hybrid energy harvester.
NASA Astrophysics Data System (ADS)
Yang, Yangyiwei; Shi, Xiang; Lan, Haoran; Xiao, Zhao; Dong, Ying; Liu, Yaoze; Yang, Tongqing
2015-04-01
In this article, behaviors are investigated when the piezoelectric harvester array, consisting of four lead zirconate-titanate (PZT) circular diaphragms, charges ultracapacitors. It exhibits that V-I characteristic of the harvester array is approximately linear within 3RC, demonstrates that the array could be equivalent as the linear source. Relevant factors on ultracapacitor charging power P, including equivalent circuitry impedance R, charging capacitor C, operating frequency f, and connection patterns, are also studied. Meanwhile, interrelation between energy charging efficiency ? and maximum charging power PMS is demonstrated, which is also used to find out the best condition for the harvester array's operation. It exhibits that PZT harvester array connected in pattern of rectifying-parallel will have higher charging efficiency.
Vibration harvesting in traffic tunnels to power wireless sensor nodes
NASA Astrophysics Data System (ADS)
Wischke, M.; Masur, M.; Kröner, M.; Woias, P.
2011-08-01
Monitoring the traffic and the structural health of traffic tunnels requires numerous sensors. Powering these remote and partially embedded sensors from ambient energies will reduce maintenance costs, and improve the sensor network performance. This work reports on vibration levels detected in railway and road tunnels as a potential energy source for embedded sensors. The measurement results showed that the vibrations at any location in the road tunnel and at the wall in the railway tunnel are too small for useful vibration harvesting. In contrast, the railway sleeper features usable vibrations and sufficient mounting space. For this application site, a robust piezoelectric vibration harvester was designed and equipped with a power interface circuit. Within the field test, it is demonstrated that sufficient energy is harvested to supply a microcontroller with a radio frequency (RF) interface.
Extremely low-loss rectification methodology for low-power vibration energy harvesters
NASA Astrophysics Data System (ADS)
Tiwari, R.; Ryoo, K.; Schlichting, A.; Garcia, E.
2013-06-01
Because of its promise for the generation of wireless systems, energy harvesting technology using smart materials is the focus of significant reported effort. Various techniques and methodologies for increasing power extraction have been tested. One of the key issues with the existing techniques is the use of diodes in the harvesting circuits with a typical voltage drop of 0.7 V. Since most of the smart materials, and other transducers, do not produce large voltage outputs, this voltage drop becomes significant in most applications. Hence, there is a need for designing a rectification method that can convert AC to DC with minimal losses. This paper describes a new mechanical rectification scheme, designed using reed switches, in a full-bridge configuration that shows the capability of working with signals from millivolts to a few hundred volts with extremely low losses. The methodology has been tested for piezoelectric energy harvesters undergoing mechanical excitation.
Development of energy harvester system for avionics
NASA Astrophysics Data System (ADS)
Hadas, Z.; Vetiska, V.; Ancik, Z.; Ondrusek, C.; Singule, V.
2013-05-01
This paper deals with an energy harvesting system for avionics; it is an energy source for a unit which is used for wireless monitoring or autonomous control of a small aircraft engine. This paper is focused on development process of energy harvesting system from mechanical vibrations in the engine area. The used energy harvesting system consists of an electro-magnetic energy harvester, power management and energy storage element. The energy harvesting system with commercial power management circuits have to be tested and verified measured results are used for an optimal redesign of the electro-magnetic harvester. This developmental step is necessary for the development of the optimal vibration energy harvesting system.
Investigation of gap-closing interdigitated capacitors for electrostatic vibration energy harvesting
NASA Astrophysics Data System (ADS)
Oxaal, John; Foster, Daniel; Hella, Mona; Borca-Tasciuc, Diana-Andra
2015-10-01
This paper reports on the dynamic characteristics of a MEMS electrostatic harvester employing interdigitated gap-closing topology. Devices are fabricated using SOIMUMPS technology and are characterized with and without biasing voltages for a broad range of excitation accelerations. At low vibration amplitudes the presence of a dc bias causes the resonant frequency peak to shift to lower frequencies with increasing bias. At higher vibration amplitudes the dynamic response of the devices exhibits the behavior of a Duffing oscillator with spring softening due to nonlinear stiffness attributed to the effect of electrostatic forces. Specifically, the devices exhibit sweep direction hysteresis with jump phenomena due to the multivaluedness of the response curve. Amplitude sweeps at constant frequency and varying bias voltage also show jump phenomena, highlighting how slight differences in operating conditions dramatically affect device performance. Spring hardening effects are reported for devices contaminated with dust particles. The paper also discusses SOIMUMPS limitations, the importance of reducing off-axis vibration during testing, characterization methods, and the effect of grounding on parasitic capacitance.
NASA Astrophysics Data System (ADS)
Halim, M. A.; Cho, H. O.; Park, J. Y.
2014-11-01
We have presented a frequency up-converted hybrid type (Piezoelectric and Electromagnetic) vibration energy harvester that can be used in powering portable and wearable smart devices by handy motion. A transverse impact mechanism has been employed for frequency up-conversion. Use of two transduction mechanisms increases the output power as well as power density. The proposed device consists of a non-magnetic spherical ball (freely movable at handy motion frequency) to impact periodically on the parabolic top of a piezoelectric (PZT) cantilevered mass by sliding over it, allowing it to vibrate at its higher resonant frequency and generates voltage by virtue of piezoelectric effect. A magnet attached to the cantilever vibrates along with it at the same frequency and a relative motion between the magnet and a coil placed below it, induces emf voltage across the coil terminals as well. A macro-scale prototype of the harvester has been fabricated and tested by handy motion. With an optimum magnet-coil overlap, a maximum 0.98mW and 0.64mW peak powers have been obtained from the piezoelectric and the electromagnetic transducers of the proposed device while shaken, respectively. It offers 84.4?Wcm-3 peak power density.
Tunable nonlinear piezoelectric vibration harvester
NASA Astrophysics Data System (ADS)
Neiss, S.; Goldschmidtboeing, F.; Kroener, M.; Woias, P.
2014-11-01
Nonlinear piezoelectric energy harvesting generators can provide a large bandwidth combined with a good resonant power output. However, the frequency response is characterized by a strong hysteresis making a technical use difficult if the hysteresis cannot be compensated. We propose a tuning mechanism that allows both, a compensation of the hysteresis as well as maintaining the optimal work point. The compensation algorithm can reduce the hysteresis to a minimum of only 1.5 Hz and maintain a high energy oscillation in a large frequency window between 53.3 Hz and 74.5 Hz.
NASA Astrophysics Data System (ADS)
Lumentut, Mikail F.; Howard, Ian M.
2016-02-01
This paper focuses on the primary development of novel numerical and analytical techniques of the modal damped vibration energy harvesters with arbitrary proof mass offset. The key equations of electromechanical finite element discretisation using the extended Lagrangian principle are revealed and simplified to give matrix and scalar forms of the coupled system equations, indicating the most relevant numerical technique for the power harvester research. To evaluate the performance of the numerical study, the analytical closed-form boundary value equations have been developed using the extended Hamiltonian principle. The results from the electromechanical frequency response functions (EFRFs) derived from two theoretical studies show excellent agreement with experimental studies. The benefit of the numerical technique is in providing effective and quick predictions for analysing parametric designs and physical properties of piezoelectric materials. Although analytical technique provides a challenging process for analysing the complex smart structure, it shows complementary study for validating the numerical technique.
NASA Astrophysics Data System (ADS)
Lajimi, S. A. M.; Friswell, M. I.
2015-04-01
For a nonlinear beam-mass system used to harvest vibratory energy, the two-mode approximation of the response is computed and compared to the single-mode approximation of the response. To this end, the discretized equations of generalized coordinates are developed and studied using a computational method. By obtaining phase-portraits and time-histories of the displacement and voltage, it is shown that the strong nonlinearity of the system affects the system dynamics considerably. By comparing the results of single- and two-mode approximations, it is shown that the number of mode shapes affects the dynamics of the response. Varying the tip-mass results in different structural configurations namely linear, pre-buckled nonlinear, and post-buckled nonlinear configurations. The nonlinear dynamics of the system response are investigated for vibrations about static equilibrium points arising from the buckling of the beam. Furthermore, it is demonstrated that the harvested power is affected by the system configuration.
NASA Astrophysics Data System (ADS)
Colin, M.; Basrour, S.; Rufer, L.
2013-05-01
Current version of implantable cardioverter defibrillators (ICDs) and pacemakers consists of a battery-powered pulse generator connected onto the heart through electrical leads inserted through the veins. However, it is known that long-term lead failure may occur and cause a dysfunction of the device. When required, the removal of the failed leads is a complex procedure associated with a potential risk of mortality. As a consequence, the main players in the field of intracardiac implants prepare a next generation of devices: miniaturized and autonomous leadless implants, which could be directly placed inside the heart. In this paper, we discuss the frequency content of a heart vibration spectrum, and the dimensional restrictions in the case of a leadless pacemaker. In combination with the requirements in terms of useable energy, we will present a design study of a resonant piezoelectric scavenger aimed at powering such a device. In particular, we will show how the frequency-volume-energy requirement leads to new challenges in terms of power densities, which are to be addressed through implementation of innovative piezoelectric thick films fabrication processes. This paper also presents the simulation, fabrication and the testing of an ultralow frequency (15Hz) resonant piezoelectric energy harvester prototype. Using both harmonic (50mg) and real heart-induced vibrations, we obtained an output power of 60?W and 10?W respectively. Finally, we will place emphasis on the new constraint represented by the gravitational (orientation) sensitivity inherent to these ultra low frequency resonant energy harvesters.
Ultra wide-bandwidth micro energy harvester
Hajati, Arman
2011-01-01
An ultra wide-bandwidth resonating thin film PZT MEMS energy harvester has been designed, modeled, fabricated and tested. It harvests energy from parasitic ambient vibration at a wide range of amplitude and frequency via ...
Piezoelectric MEMS for energy harvesting
Kim, Sang-Gook
Piezoelectric microelectromechanical systems (MEMS) have been proven to be an attractive technology for harvesting small magnitudes of energy from ambient vibrations. This technology promises to eliminate the need for ...
Vibration shape effects on the power output in piezoelectric vibro-impact energy harvesters
NASA Astrophysics Data System (ADS)
Twiefel, Jens
2013-04-01
Vibro-Impcact harvesting devices are one concept to increase the bandwidth of resonant operated piezoelectric vibration generators. The fundamental setup is a piezoelectric bending element, where the deflection is limited by two stoppers. After starting the system in resonance operation the bandwidth increases towards higher frequencies as soon the deflection reach the stopper. If the stoppers are rigid, the frequency response gives constant amplitude for increasing frequencies, as long the system is treated as ideal one-DOF system with symmetric stoppers. In consequence, the bandwidth is theoretically unlimited large. However, such a system also has two major drawbacks, firstly the complicated startup mechanism and secondly the tendency to drop from the high constant branch in the frequency response on the much smaller linear branch if the system is disturbed. Nevertheless, the system has its application wherever the startup problem can be solved. Most modeling approaches utilize modal one-DOF models to describe the systems behavior and do not tread the higher harmonics of the beam. This work investigates the effects of the stoppers on the vibration shape of the piezoelectric beam, wherefore a finite element model is used. The used elements are one-dimensional two node elements based on the Timoshenko-beam theory. The finite element code is implemented in Matlab. The model is calculated utilizing time step integration for simulation, to reduce the computation time an auto-resonant calculation method is implemented. A control loop including positive feedback and saturation is used to create a self-excited system. Therefore, the system is always operated in resonance (on the backbone curve) and the frequency is a direct result of the computation. In this case tip velocity is used as feedback. This technique allows effective parametric studies. Investigated parameters include gap, excitation amplitude, tip mass as well as the stiffness of the stopper. The stress and strain distribution as well as the generated electrical power is analyzed with respect to the proper operation range.
Design of electromagnetic energy harvesters for large-scale structural vibration applications
NASA Astrophysics Data System (ADS)
Cassidy, Ian L.; Scruggs, Jeffrey T.; Behrens, Sam
2011-03-01
This paper reports on the design and experimental validation of transducers for energy harvesting from largescale civil structures, for which the power levels can be above 100W, and disturbance frequencies below 1Hz. The transducer consists of a back-driven ballscrew, coupled to a permanent-magnet synchronous machine, and power harvesting is regulated via control of a four-quadrant power electronic drive. Design tradeoffs between the various subsystems (including the controller, electronics, machine, mechanical conversion, and structural system) are illustrated, and an approach to device optimization is presented. Additionally, it is shown that nonlinear dissipative behavior of the electromechanical system must be properly characterized in order to assess the viability of the technology, and also to correctly design the matched impedance to maximize harvested power. An analytical expression for the average power generated across a resistive load is presented, which takes the nonlinear dissipative behavior of the device into account. From this expression the optimal resistance is determined to maximize power for an example in which the transducer is coupled to base excited tuned mass damper (TMD). Finally, the results from the analytical model are compared to an experimental system that uses hybrid testing to simulated the dynamics of the TMD.
Dominguez-Garcia, Alejandro
HARVESTING ENERGY FROM MOTH VIBRATIONS DURING FLIGHT S.C. Chang1, F.M. Yaul1, A. Dominguez-Garcia3 the design, fabrication, and testing of a harvester that extracts energy from moth-body vibrations during flight. The target moth is manduca sexta, which has a payload capacity near 1 g, and a dorsal payload
NASA Astrophysics Data System (ADS)
Iannacci, J.; Sordo, G.; Serra, E.; Kucera, M.; Schmid, U.
2015-05-01
In this work, we discuss the verification and preliminary experimental characterization of a MEMS-based vibration Energy Harvester (EH) design. The device, named Four-Leaf Clover (FLC), is based on a circular-shaped mechanical resonator with four petal-like mass-spring cascaded systems. This solution introduces several mechanical Degrees of Freedom (DOFs), and therefore enables multiple resonant modes and deformation shapes in the vibrations frequency range of interest. The target is to realize a wideband multi-modal EH-MEMS device, that overcomes the typical narrowband working characteristics of standard cantilevered EHs, by ensuring flexible and adaptable power source to ultra-low power electronics for integrated remote sensing nodes (e.g. Wireless Sensor Networks - WSNs) in the Internet of Things (IoT) scenario, aiming to self-powered and energy autonomous smart systems. Finite Element Method simulations of the FLC EH-MEMS show the presence of several resonant modes for vibrations up to 4-5 kHz, and level of converted power up to a few ?W at resonance and in closed-loop conditions (i.e. with resistive load). On the other hand, the first experimental tests of FLC fabricated samples, conducted with a Laser Doppler Vibrometer (LDV), proved the presence of several resonant modes, and allowed to validate the accuracy of the FEM modeling method. Such a good accordance holds validity for what concerns the coupled field behavior of the FLC EH-MEMS, as well. Both measurements and simulations performed at 190 Hz (i.e. out of resonance) showed the generation of power in the range of nW (Root Mean Square - RMS values). Further steps of this work will include the experimental characterization in a full range of vibrations, aiming to prove the whole functionality of the FLC EH-MEMS proposed design concept.
Dynamic analysis of an electrostatic energy harvesting system
Niu, Feifei
2013-01-01
Traditional small-scale vibration energy harvesters have typically low efficiency of energy harvesting from low frequency vibrations. Several recent studies have indicated that introduction of nonlinearity can significantly ...
Experimental verification of a bridge-shaped, nonlinear vibration energy harvester
Gafforelli, Giacomo Corigliano, Alberto; Xu, Ruize; Kim, Sang-Gook
2014-11-17
This paper reports a comprehensive modeling and experimental characterization of a bridge shaped nonlinear energy harvester. A doubly clamped beam at large deflection requires stretching strain in addition to the bending strain to be geometrically compatible, which stiffens the beam as the beam deflects and transforms the dynamics to a nonlinear regime. The Duffing mode non-linear resonance widens the frequency bandwidth significantly at higher frequencies than the linear resonant frequency. The modeling includes a nonlinear measure of strain coupled with piezoelectric constitutive equations which end up in nonlinear coupling terms in the equations of motion. The main result supports that the power generation is bounded by the mechanical damping for both linear and nonlinear harvesters. Modeling also shows the power generation is over a wider bandwidth in the nonlinear case. A prototype is manufactured and tested to measure the power generation at different load resistances and acceleration amplitudes. The prototype shows a nonlinear behavior with well-matched experimental data to the modeling.
NASA Astrophysics Data System (ADS)
Dhanwani, Manish A.; Sarkar, Abhijit; Patnaik, B. S. V.
2013-11-01
In the present study, a lumped parameter model for vortex-induced vibrations is analysed. In this work, the vortex-induced vibrations of an elastically mounted rigid cylinder are able to move in-line and transverse to the flow with equal mass ratio and natural frequencies. A simplified lumped mass model is proposed to study the two degree of freedom (dof) structural oscillator. A classical van der Pol equation along with acceleration coupling, models the near wake dynamics describing the fluctuating nature of vortex shedding. The model dynamics is investigated analytically and the results are compared for moderate mass ratios. The results predicted using this model show a good agreement with the experimental data. The dependence of stream-wise displacement on mass and damping is explored. The cause of cross-flow displacement magnification due to freedom to move in stream-wise direction is also explored using the proposed model. Apart from these two degrees of freedom, the cylinder can also undergo rotation about its centre of mass. The effect of freedom to move in this rotational degree of freedom is exploited to our advantage by applying it to the VIVACE (Vortex induced vibration aquatic clean energy) design which was originally proposed by Bernitsas et al. (2008). The original design was not reported to be the optimal one and the set-up was shown to work only for a given flow velocity. But, the flow environment keeps changing and hence there is a need to bring in robustness and optimize the proposed design. The values of optimized spring stiffness have been found using the lumped mass model. The design is made robust by exploiting the rotational mode. This mode is triggered by varying the overhang lengths in accordance with the varying flow velocity in order to strike resonance for a certain flow regime.
Kim, Moonkeun; Lee, Sang-Kyun; Yang, Yil Suk; Jeong, Jaehwa; Min, Nam Ki; Kwon, Kwang-Ho
2013-12-01
We fabricated dual-beam cantilevers on the microelectromechanical system (MEMS) scale with an integrated Si proof mass. A Pb(Zr,Ti)O3 (PZT) cantilever was designed as a mechanical vibration energy-harvesting system for low power applications. The resonant frequency of the multilayer composition cantilevers were simulated using the finite element method (FEM) with parametric analysis carried out in the design process. According to simulations, the resonant frequency, voltage, and average power of a dual-beam cantilever was 69.1 Hz, 113.9 mV, and 0.303 microW, respectively, at optimal resistance and 0.5 g (gravitational acceleration, m/s2). Based on these data, we subsequently fabricated cantilever devices using dual-beam cantilevers. The harvested power density of the dual-beam cantilever compared favorably with the simulation. Experiments revealed the resonant frequency, voltage, and average power density to be 78.7 Hz, 118.5 mV, and 0.34 microW, respectively. The error between the measured and simulated results was about 10%. The maximum average power and power density of the fabricated dual-beam cantilever at 1 g were 0.803 microW and 1322.80 microW cm(-3), respectively. Furthermore, the possibility of a MEMS-scale power source for energy conversion experiments was also tested. PMID:24266167
Piezoelectric Energy Harvesting From Flutter
NASA Astrophysics Data System (ADS)
Norouzi, Soroush
With the increasing need for alternative sources of energy, a great deal of attention is drawn to harvesting energy from ambient vibration. These vibrations may be caused by fluid forces acting upon a structure. When a flexible structure is subject to a fluid flow, it loses stability at a certain flow velocity and starts to vibrate. This self-induced motion is called flutter where energy is continuously transferred from the fluid to the structure. In this study a piezoelectric film sensor is used as a fluttering object, to convert the motion to electrical energy, and the energy harvesting capacity of the proposed concept is investigated. An experimental setup, composed of data acquisition methods, is designed and the findings are validated by original test data. The results are also compared to similar literature and it is concluded that the proposed energy harvesting technique meets the requirements of the intended application.
Scaling effects for piezoelectric energy harvesters
NASA Astrophysics Data System (ADS)
Zhu, D.; Beeby, S. P.
2015-05-01
This paper presents a fundamental investigation into scaling effects for the mechanical properties and electrical output power of piezoelectric vibration energy harvesters. The mechanical properties investigated in this paper include resonant frequency of the harvester and its frequency tunability, which is essential for the harvester to operate efficiently under broadband excitations. Electrical output power studied includes cases when the harvester is excited under both constant vibration acceleration and constant vibration amplitude. The energy harvester analysed in this paper is based on a cantilever structure, which is typical of most vibration energy harvesters. Both detailed mathematical derivation and simulation are presented. Furthermore, various piezoelectric materials used in MEMS and non-MEMS harvesters are also considered in the scaling analysis.
Design and fabrication of a PZT cantilever for low frequency vibration energy harvesting.
Kim, Moonkeun; Hwang, Beomseok; Min, Nam Ki; Jeong, Jaehwa; Kwon, Kwang-Ho; Park, Kang-Bak
2011-07-01
In this study, a PZT cantilever with a Si proof mass is designed and fabricated for a low frequency energy harvesting application. A mathematical model of a multi-layer composite beam was derived and applied in a parametric analysis of the piezoelectric cantilever. Finally, the dimensions of the cantilever were determined for the resonant frequency of the cantilever. Our cantilever design was based on MATLAB and ANSYS simulations. For this simulation, the proof mass volumes were varied from 0 to 0.5 mm3 and resonant frequencies were calculated from 833.5 Hz to 125.5 Hz, respectively. Based on simulation, we fabricated a device with beam dimensions of about 4.10 mm x 0.48 mm x 0.012 mm, and an integrated Si proof mass with dimensions of about 0.481 mm x 0.48 mm x 0.45 mm. The resonant frequency, maximum peak voltage, and highest average power of the cantilever device were 224.8 Hz, 4.8 mV, and 2.24 nW, respectively. PMID:22121746
NASA Astrophysics Data System (ADS)
Suzuki, Yuji; Miki, Daigo; Edamoto, Masato; Honzumi, Makoto
2010-10-01
In this paper, we propose a passive gap-spacing control method in order to avoid stiction between top and bottom structures in in-plane sensor/actuator/generator applications. A patterned electret using a high-performance perfluoro polymer material is employed to induce a repulsive electrostatic force. An out-of-plane repulsive force is successfully demonstrated with our early prototype, in both air and liquid. By using the present electret-based levitation method to keep the air gap, a MEMS electret generator has been developed for energy-harvesting applications. A dual-phase electrode arrangement is adopted in order to reduce the horizontal electrostatic damping force. With the present prototype, about 0.5 µW is obtained for both phases of the generator, resulting in a total power output of 1.0 µW at an acceleration of 2 g with 63 Hz. With our electromechanical model of the generator, we have confirmed that the model can mimic the response of the generator prototype.
NASA Astrophysics Data System (ADS)
Kim, In-Ho; Jang, Seon-Jun; Jung, Hyung-Jo
2013-07-01
In this paper, an innovative strategy for improving the performance of a recently developed rotational energy harvester is proposed. Its performance can be considerably enhanced by replacing the electromagnetic induction part, consisting of moving permanent magnets and a fixed solenoid coil, with a moving mass and a rotational generator (i.e., an electric motor). The proposed system is easily tuned to the natural frequency of a target structure using the position change of a proof mass. Owing to the high efficiency of the rotational generator, the device can more effectively harness electrical energy from the wind-induced vibration of a stay cable. Also, this new configuration makes the device more compact and geometrically tunable. In order to validate the effectiveness of the new configuration, a series of laboratory and field tests are carried out with the prototype of the proposed device, which is designed and fabricated based on the dynamic characteristics of the vibration of a stay cable installed in an in-service cable-stayed bridge. From the field test, it is observed that the normalized output power of the proposed system is 35.67 mW (m s-2)-2, while that of the original device is just 5.47 mW (m s-2)-2. These results show that the proposed device generates much more electrical energy than the original device. Moreover, it is verified that the proposed device can generate sufficient electricity to power a wireless sensor node placed on a cable under gentle-moderate wind conditions.
NASA Astrophysics Data System (ADS)
Renaud, M.; Altena, G.; Elfrink, R.; Goedbloed, M.; de Nooijer, C.; van Schaijk, R.
2015-08-01
The purpose of this article is to elaborate a model and the optimization guidelines for electret based harvesters with a specific electret/electrodes configuration, namely the slot-effect configuration. Slot-effect configured harvesters have been investigated experimentally by several research groups. A model describing their dynamic behavior has also been recently proposed in the literature. However, the simplifications used in the existing model can lead to inaccuracies and a refined analysis is elaborated in the present article. The model is compared with experimental measurements on MEMS fabricated devices with a corrugated electret. The electrodes dimensioning in the MEMS device are chosen so that the harvester behaves in a quasi-linear manner over its full range of displacement. This quasi-linearity simplifies greatly the device optimization. Indeed, the behavior of the developed electrostatic harvester is shown to be very comparable to that of piezoelectric harvesters, which are very well understood and documented. The influence of several design parameters on output power performance is investigated. As long as pull-in and breakdown voltage effects can be avoided, the electret surface potential should be maximized and the air gap minimized. We also investigate theoretically the influence of three types of electret on the generated power: planar, corrugated with partial charge coverage, and corrugated with full charge coverage. With the dimensions corresponding to our MEMS devices, the output power characteristics for the three types of electret are similar. However, it is shown that this is not always true. In some conditions, corrugated electrets with full charge coverage are detrimental for the generated power.
NASA Astrophysics Data System (ADS)
Asanuma, H.; Hara, M.; Oguchi, H.; Kuwano, H.
2015-10-01
We investigated the dependence of output power, frequency band width, and resonance frequency on the initial air gap for electret-based out-of-plane vibration energy harvesters, both numerically and experimentally. In this investigation, the external acceleration and surface charge densities of the electret were held constant. The numerical investigation predicted the following results: (1) an optimum value exists in the initial air gap to maximize the output power; and (2) enhanced electrostatic forces with decreasing the initial air gap emphasize the soft spring effect, which widens the frequency band width and lowers the resonance frequency. The experimental results showed behaviour consistent with the numerical predictions. The maximum output power in experiment was 4.0??W at the optimum initial air gap of 0.43?mm when the external acceleration and the frequency were 4.9?m?s-2 and 102?Hz, respectively. With reducing the initial air gap to 0.28?mm, the frequency band width increased to 17?Hz, a 2.6-fold increase over the optimum initial air gap. The peak output power at the initial air gap of 0.28?mm was 2.7??W, when the external acceleration and frequency were 4.9?m?s-2 and 96?Hz, respectively.
NASA Astrophysics Data System (ADS)
Xu-Xu, J.; Barrero-Gil, A.; Velazquez, A.
2015-11-01
This paper presents a theoretical study of the coupling between a vortex-induced vibration (VIV) cylindrical resonator and its associated linear electromagnetic generator. The two-equation mathematical model is based on a dual-mass formulation in which the dominant masses are the stator and translator masses of the generator. The fluid-structure interaction implemented in the model equations follows the so-called ‘advanced forcing model’ whose closure relies on experimental data. The rationale to carry out the study is the fact that in these types of configurations there is a two-way interaction between the moving parts in such a way that their motions influence each other simultaneously, thereby affecting the energy actually harvested. It is believed that instead of mainly resorting to complementary numerical simulations, a theoretical model can shed some light on the nature of the interaction and, at the same time, provide scaling laws that can be used for practical design and optimization purposes. It has been found that the proposed configuration has a maximum hydrodynamic to mechanical to electrical conversion efficiency (based on the VIV resonator oscillation amplitude) of 8%. For a cylindrical resonator 10 cm long with a 2 cm diameter, this translates into an output power of 20 to 160 mW for water stream velocities in the range from 0.5 to 1 m s-1.
NASA Astrophysics Data System (ADS)
Dudka, A.; Basset, P.; Cottone, F.; Blokhina, E.; Galayko, D.
2013-12-01
This paper reports on an electrostatic Vibration Energy Harvester (e-VEH) system, for which the energy conversion process is initiated with a low bias voltage and is compatible with wideband stochastic external vibrations. The system employs the auto-synchronous conditioning circuit topology with the use of a novel dedicated integrated low-power high-voltage switch that is needed to connect the charge pump and flyback - two main parts of the used conditioning circuit. The proposed switch is designed and implemented in AMS035HV CMOS technology. Thanks to the proposed switch device, which is driven with a low-voltage ground-referenced logic, the e-VEH system may operate within a large voltage range, from a pre-charge low voltage up to several tens volts. With such a high-voltage e-VEH operation, it is possible to obtain a strong mechanical coupling and a high rate of vibration energy conversion. The used transducer/resonator device is fabricated with a batch-processed MEMS technology. When excited with stochastic vibrations having an acceleration level of 0.8 g rms distributed in the band 110-170 Hz, up to 0.75 ?W of net electrical power has been harvested with our system. This work presents an important milestone in the challenge of designing a fully integrated smart conditioning interface for the capacitive e-VEHs.
Energy Harvesting From Low Frequency Applications Using Piezoelectric Materials
Li, Huidong; Tian, Chuan; Deng, Zhiqun
2014-11-06
This paper reviewed the state of research on piezoelectric energy harvesters. Various types of harvester configurations, piezoelectric materials, and techniques used to improve the mechanical-to-electrical energy conversion efficiency were discussed. Most of the piezoelectric energy harvesters studied today have focused on scavenging mechanical energy from vibration sources due to their abundance in both natural and industrial environments. Cantilever beams have been the most studied structure for piezoelectric energy harvester to date because of the high responsiveness to small vibrations.
NASA Astrophysics Data System (ADS)
Ray, Chase A.; Anton, Steven R.
2015-04-01
Electronic devices are high demand commodities in today's world, and such devices will continue increasing in popularity. Currently, batteries are implemented to provide power to these devices; however, the need for battery replacement, their cost, and the waste associated with battery disposal present a need for advances in self-powered technology. Energy harvesting technology has great potential to alleviate the drawbacks of batteries. In this work, a novel piezoelectret foam material is investigated for low-level energy harvesting. Specifically, piezoelectret foam assembled in a multilayer stack configuration is explored. Modeling and experimentation of the stack behavior when excited in compression at low frequencies are performed to investigate piezoelectret foam as a multilayer energy harvester. An examination of modeling piezoelectret foam as a stack with an equivalent circuit is made following recently published work and is used in this study. A 20-layer prototype device is fabricated and experimentally tested via harmonic base excitation. Electromechanical testing is performed by compressing the foam stack to obtain output electrical energy; consequently, allowing the frequency response between input mechanical energy and output electrical energy to be developed. Modeling results are compared to the experimental measurements to assess the fidelity of the model. Lastly, energy harvesting experimentation in which the device is subject to harmonic base excitation at the natural frequency is conducted to determine the ability of the piezoelectret foam stack to successfully charge a capacitor.
Fluid flow nozzle energy harvesters
NASA Astrophysics Data System (ADS)
Sherrit, Stewart; Lee, Hyeong Jae; Walkemeyer, Phillip; Winn, Tyler; Tosi, Luis Phillipe; Colonius, Tim
2015-04-01
Power generation schemes that could be used downhole in an oil well to produce about 1 Watt average power with long-life (decades) are actively being developed. A variety of proposed energy harvesting schemes could be used to extract energy from this environment but each of these has their own limitations that limit their practical use. Since vibrating piezoelectric structures are solid state and can be driven below their fatigue limit, harvesters based on these structures are capable of operating for very long lifetimes (decades); thereby, possibly overcoming a principle limitation of existing technology based on rotating turbo-machinery. An initial survey [1] identified that spline nozzle configurations can be used to excite a vibrating piezoelectric structure in such a way as to convert the abundant flow energy into useful amounts of electrical power. This paper presents current flow energy harvesting designs and experimental results of specific spline nozzle/ bimorph design configurations which have generated suitable power per nozzle at or above well production analogous flow rates. Theoretical models for non-dimensional analysis and constitutive electromechanical model are also presented in this paper to optimize the flow harvesting system.
Synchronized charge extraction for aeroelastic energy harvesting
NASA Astrophysics Data System (ADS)
Zhao, Liya; Tang, Lihua; Wu, Hao; Yang, Yaowen
2014-03-01
Aeroelastic instabilities have been frequently exploited for energy harvesting purpose to power standalone electronic systems, such as wireless sensors. Meanwhile, various energy harvesting interface circuits, such as synchronized charge extraction (SCE) and synchronized switching harvesting on inductor (SSHI), have been widely pursued in the literature for efficiency enhancement of energy harvesting from existing base vibrations. These interfaces, however, have not been applied for aeroelastic energy harvesting. This paper investigates the feasibility of the SCE interface in galloping-based piezoelectric energy harvesting, with a focus on its benefit for performance improvement and influence on the galloping dynamics in different electromechanical coupling regimes. A galloping-based piezoelectric energy harvester (GPEH) is prototyped with an aluminum cantilever bonded with a piezoelectric sheet. Wind tunnel test is conducted with a simple electrical interface composed of a resistive load. Circuit simulation is performed with equivalent circuit representation of the GPEH system and confirmed by experimental results. Consequently, a self-powered SCE interface is implemented with the capability of self peak-detecting and switching. Circuit simulation for various electromechanical coupling cases shows that the harvested power with SCE interface for GPEH is independent of the electrical load, similar to that for a vibration-based piezoelectric energy harvester (VPEH). The SCE interface outperforms the standard interface if the electromechanical coupling is weak, and requires much less piezoelectric material to achieve the maximum power output. Moreover, influence of electromechanical coupling on the dynamics of GPEH with SCE is found sensitive to the wind speed.
Porous ferroelectrics for energy harvesting applications
NASA Astrophysics Data System (ADS)
Roscow, J.; Zhang, Y.; Taylor, J.; Bowen, C. R.
2015-11-01
This paper provides an overview of energy harvesting using ferroelectric materials, with a particular focus on the energy harvesting capabilities of porous ferroelectric ceramics for both piezo- and pyroelectric harvesting. The benefits of introducing porosity into ferro- electrics such as lead zirconate titanate (PZT) has been known for over 30 years, but the potential advantages for energy harvesting from both ambient vibrations and temperature fluctuations have not been studied in depth. The article briefly discusses piezoelectric and pyro- electric energy harvesting, before evaluating the potential benefits of porous materials for increasing energy harvesting figures of merits and electromechanical/electrothermal coupling factors. Established processing routes are evaluated in terms of the final porous structure and the resulting effects on the electrical, thermal and mechanical properties.
NASA Astrophysics Data System (ADS)
Leadenham, S.; Erturk, A.
2014-11-01
Over the past few years, nonlinear oscillators have been given growing attention due to their ability to enhance the performance of energy harvesting devices by increasing the frequency bandwidth. Duffing oscillators are a type of nonlinear oscillator characterized by a symmetric hardening or softening cubic restoring force. In order to realize the cubic nonlinearity in a cantilever at reasonable excitation levels, often an external magnetic field or mechanical load is imposed, since the inherent geometric nonlinearity would otherwise require impractically high excitation levels to be pronounced. As an alternative to magnetoelastic structures and other complex forms of symmetric Duffing oscillators, an M-shaped nonlinear bent beam with clamped end conditions is presented and investigated for bandwidth enhancement under base excitation. The proposed M-shaped oscillator made of spring steel is very easy to fabricate as it does not require extra discrete components to assemble, and furthermore, its asymmetric nonlinear behavior can be pronounced yielding broadband behavior under low excitation levels. For a prototype configuration, linear and nonlinear system parameters extracted from experiments are used to develop a lumped-parameter mathematical model. Quadratic damping is included in the model to account for nonlinear dissipative effects. A multi-term harmonic balance solution is obtained to study the effects of higher harmonics and a constant term. A single-term closed-form frequency response equation is also extracted and compared with the multi-term harmonic balance solution. It is observed that the single-term solution overestimates the frequency of upper saddle-node bifurcation point and underestimates the response magnitude in the large response branch. Multi-term solutions can be as accurate as time-domain solutions, with the advantage of significantly reduced computation time. Overall, substantial bandwidth enhancement with increasing base excitation is validated experimentally, analytically, and numerically. As compared to the 3 dB bandwidth of the corresponding linear system with the same linear damping ratio, the M-shaped oscillator offers 3200, 5600, and 8900 percent bandwidth enhancement at the root-mean-square base excitation levels of 0.03g, 0.05g, and 0.07g, respectively. The M-shaped configuration can easily be exploited in piezoelectric and electromagnetic energy harvesting as well as their hybrid combinations due to the existence of both large strain and kinetic energy regions. A demonstrative case study is given for electromagnetic energy harvesting, revealing the importance of higher harmonics and the need for multi-term harmonic balance analysis for predicting the electrical power output accurately.
Harvesting Raindrop Energy with Piezoelectrics: a Review
NASA Astrophysics Data System (ADS)
Wong, Chin-Hong; Dahari, Zuraini; Abd Manaf, Asrulnizam; Miskam, Muhammad Azman
2015-01-01
Harvesting vibration energy from piezoelectric material impacted by raindrops has proved to be a promising approach for future applications. A piezoelectric harvester has interesting advantages such as simple structure, easy fabrication, reduced number of components, and direct conversion of vibrations to electrical charge. Extensive research has been carried out and is still underway to explore this technique for practical applications. This review provides a comprehensive picture of global research and development of raindrop energy harvesting using piezoelectric material to enable researchers to determine the direction of further investigation. The work published so far in this area is reviewed and summarized with relevant suggestions for future work. In addition, a brief experiment was carried out to investigate the suitable piezoelectric structure for raindrop energy harvesting. Results showed that the bridge structure generated a higher voltage compared with the cantilever structure.
NASA Astrophysics Data System (ADS)
Killoran, N.; Huelga, S. F.; Plenio, M. B.
2015-10-01
Recent evidence suggests that quantum effects may have functional importance in biological light-harvesting systems. Along with delocalized electronic excitations, it is now suspected that quantum coherent interactions with certain near-resonant vibrations may contribute to light-harvesting performance. However, the actual quantum advantage offered by such coherent vibrational interactions has not yet been established. We investigate a quantum design principle, whereby coherent exchange of single energy quanta between electronic and vibrational degrees of freedom can enhance a light-harvesting system's power above what is possible by thermal mechanisms alone. We present a prototype quantum heat engine which cleanly illustrates this quantum design principle and quantifies its quantum advantage using thermodynamic measures of performance. We also demonstrate the principle's relevance in parameter regimes connected to natural light-harvesting structures.
Flexible electret energy harvesters with parylene electret on PDMS substrates
NASA Astrophysics Data System (ADS)
Chiu, Yi; Wu, Shih-Hsien
2013-12-01
Currently, most vibrational energy harvesters have rigid and resonant structures to harvest energy from periodic motions in specific directions. However, in some situations the motion is random and aperiodic; or the targeted energy source is the strain energy in deformation, rather than the kinetic energy in vibration. Therefore we propose and demonstrate a PDMS-based flexible energy harvester with parylene-C electret that can be attached to any deformable surfaces to harvest the stain energy caused by external deformation. The proposed flexible harvester was fabricated and characterized. The measured power at 20 Hz is 0.18 ?W and 82 nW in the compression and bending modes, respectively. Such a harvester has the potential for wearable and implantable electronics applications.
A nonlinear piezoelectric energy harvester for various mechanical motions
NASA Astrophysics Data System (ADS)
Fan, Kangqi; Chang, Jianwei; Pedrycz, Witold; Liu, Zhaohui; Zhu, Yingmin
2015-06-01
This study presents a nonlinear piezoelectric energy harvester with intent to scavenge energy from diverse mechanical motions. The harvester consists of four piezoelectric cantilever beams, a cylindrical track, and a ferromagnetic ball, with magnets integrated to introduce the magnetic coupling between the ball and the beams. The experimental results demonstrate that the harvester is able to collect energy from various directions of vibrations. For the vibrations perpendicular to the ground, the maximum peak voltage is increased by 3.2 V and the bandwidth of the voltage above 4 V is increased by more than 4 Hz compared to the results obtained when using a conventional design. For the vibrations along the horizontal direction, the frequency up-conversion is realized through the magnetic coupling. Moreover, the proposed design can harvest energy from the sway motion around different directions on the horizontal plane. Harvesting energy from the rotation motion is also achieved with an operating bandwidth of approximately 6 Hz.
The design of low-frequency, low-g piezoelectric micro energy harvesters
Xu, Ruize, S.M. Massachusetts Institute of Technology
2012-01-01
A low-frequency, low-g piezoelectric MEMS energy harvester has been designed. Theoretically, this new generation energy harvester will generate electric power from ambient vibrations in the frequency range of 200~30OHz at ...
Experiment and modeling of a two-dimensional piezoelectric energy harvester
NASA Astrophysics Data System (ADS)
Yang, Yaowen; Wu, Hao; Kiong Soh, Chee
2015-12-01
Vibration energy harvesting using piezoelectric materials has attracted much research interest in recent years. Numerous efforts have been devoted to improving the efficiency of vibration energy harvesters and broadening their bandwidths. In most reported literature, energy harvesters are designed to harvest energy from vibration source with a specific excitation direction. However, a practical environmental vibration source may include multiple components from different directions. Thus, it is an important concern to design a vibration energy harvester to be adaptive to multiple excitation directions. In this article, a piezoelectric energy harvester with frame configuration is proposed to achieve two-dimensional (2D) vibration energy harvesting. The harvester works in two fundamental modes, i.e., its vertical and horizontal vibration modes. By tuning the structural parameters, the harvester can capture vibration energy from arbitrary directions in a 2D plane. Experimental studies are carried out to prove its feasibility. A finite element model and an equivalent circuit model are built to simulate the system and validate the experiment outcomes. The study of this 2D energy harvester indicates its promising potential in practical vibration scenarios.
Piezoelectric energy harvesting solutions.
Caliò, Renato; Rongala, Udaya Bhaskar; Camboni, Domenico; Milazzo, Mario; Stefanini, Cesare; de Petris, Gianluca; Oddo, Calogero Maria
2014-01-01
This paper reviews the state of the art in piezoelectric energy harvesting. It presents the basics of piezoelectricity and discusses materials choice. The work places emphasis on material operating modes and device configurations, from resonant to non-resonant devices and also to rotational solutions. The reviewed literature is compared based on power density and bandwidth. Lastly, the question of power conversion is addressed by reviewing various circuit solutions. PMID:24618725
Piezoelectric Energy Harvesting Solutions
Caliò, Renato; Rongala, Udaya Bhaskar; Camboni, Domenico; Milazzo, Mario; Stefanini, Cesare; de Petris, Gianluca; Oddo, Calogero Maria
2014-01-01
This paper reviews the state of the art in piezoelectric energy harvesting. It presents the basics of piezoelectricity and discusses materials choice. The work places emphasis on material operating modes and device configurations, from resonant to non-resonant devices and also to rotational solutions. The reviewed literature is compared based on power density and bandwidth. Lastly, the question of power conversion is addressed by reviewing various circuit solutions. PMID:24618725
NASA Astrophysics Data System (ADS)
Shen, Hui; Qiu, Jinhao; Ji, Hongli; Zhu, Kongjun; Balsi, Marco
2010-11-01
This paper presents a new technique for optimized energy harvesting using piezoelectric microgenerators called enhanced synchronized switch harvesting (ESSH). This technique is based on the concept of synchronized switch harvesting (SSH), a nonlinear technique developed for energy harvesting from structural vibration. Compared with the standard technique of energy harvesting, the new technique dramatically increases the harvested power by almost 300% at resonance frequencies in the same vibration conditions, and also ensures an optimal harvested power whatever the load connected to the microgenerator. Furthermore, the new technique (ESSH) in this paper can be truly self-powered; a self-powered circuit which implements the technique is proposed. In addition, the overall power dissipation for the control circuitry is relatively constant (only about 121 µW), which is more attractive especially at high excitation. Because the new technique (ESSH) in this paper can be truly self-powered, no external power supply is needed, making the system suitable for more application fields, especially in remote operation.
Energy Harvesting Diamond Channel with Energy Cooperation
Ulukus, Sennur
Energy Harvesting Diamond Channel with Energy Cooperation Berk Gurakan Sennur Ulukus Department@umd.edu Abstract--We consider the energy harvesting diamond channel, where the source and two relays harvest energy the option of wirelessly transferring some of its energy to the relays via energy cooperation. We find
A low frequency nonlinear energy harvester with large bandwidth utilizing magnet levitation
NASA Astrophysics Data System (ADS)
Zhang, Ye; Cai, C. S.; Kong, Bo
2015-04-01
The application of vibration based energy harvesting in civil infrastructures usually has to resolve two major problems, namely, the low excitation frequency and large frequency range. To this end, a nonlinear energy harvester utilizing magnet levitation is proposed in this study. The proposed harvester can convert low frequency excitations into high frequency ones in its four doubly clamped piezoelectric beams through multi-impact. A large bandwidth is expected due to the stiffness nonlinearity introduced by using magnet levitation. A theoretical model is first developed for the harvester. Then, sinusoidal vibrations and simulated bridge vibrations are used as the external excitations to verify the performance of the harvester. The simulation results show an improved robustness of the harvester under low frequency vibrations, which indicates the proposed harvester is an ideal device for energy harvesting in civil infrastructures.
Development of enhanced piezoelectric energy harvester induced by human motion.
Minami, Y; Nakamachi, E
2012-01-01
In this study, a high frequency piezoelectric energy harvester converted from the human low vibrated motion energy was newly developed. This hybrid energy harvester consists of the unimorph piezoelectric cantilever and a couple of permanent magnets. One magnet was attached at the end of cantilever, and the counterpart magnet was set at the end of the pendulum. The mechanical energy provided through the human walking motion, which is a typical ubiquitous presence of vibration, is converted to the electric energy via the piezoelectric cantilever vibration system. At first, we studied the energy convert mechanism and the performance of our energy harvester, where the resonance free vibration of unimorph cantilever with one permanent magnet under a rather high frequency was induced by the artificial low frequency vibration. The counterpart magnet attached on the pendulum. Next, we equipped the counterpart permanent magnet pendulum, which was fluctuated under a very low frequency by the human walking, and the piezoelectric cantilever, which had the permanent magnet at the end. The low-to-high frequency convert "hybrid system" can be characterized as an enhanced energy harvest one. We examined and obtained maximum values of voltage and power in this system, as 1.2V and 1.2 µW. Those results show the possibility to apply for the energy harvester in the portable and implantable Bio-MEMS devices. PMID:23366218
Energy Harvesting Communications with Continuous Energy Arrivals
Yener, Aylin
Energy Harvesting Communications with Continuous Energy Arrivals Burak Varan Kaya Tutuncuoglu Aylin--This work considers an energy harvesting transmit- ter that gathers a continuous flow of energy from intermittent sources, thus relaxing the modeling assumption of discrete amounts of harvested energy present
Multi-source energy harvesting for wireless SHM systems
NASA Astrophysics Data System (ADS)
Choi, Mijin; Farinholt, Kevin M.; Anton, Steven; Lee, Jung-Ryul; Park, Gyuhae
2013-03-01
In wireless SHM systems, energy harvesting technology is essential for a reliable long-term energy supply for wireless sensors. Conventional wireless SHM systems using single source energy harvesting (vibration, solar, and etc.) have limitations because it could not be operated adequately without enough ambient energy present. To overcome this obstacle, multi-source energy harvesting which utilizes several ambient energy sources simultaneously is necessary to accumulate enough electrical energy to power wireless embedded sensor nodes. This study proposes a multi-source energy harvesting technique using a MISO (Multiple Input, Single Output) circuit board developed and studied by the authors. For multi-source energy harvesting, piezoelectric bimorph and electro-magnetic energy harvesters are excited at the first natural frequency of each harvester, 126.7 and 12.5 Hz, respectively. Then, generated voltage from each energy harvester is combined using the MISO circuit and then used to charge a 0.1 F capacitor. Combined energy harvesting results presented better performance than that of a single energy source, demonstrating that this multi-source system could be a promising energy harvesting solution for wireless sensing systems.
An aero-elastic flutter based electromagnetic energy harvester with wind speed augmenting funnel
Stanford University
An aero-elastic flutter based electromagnetic energy harvester with wind speed augmenting funnel augmenting funnel incorporated with an aero-elastic-flutter based, energy harvester. Flutter phenomenon has for an energy harvester to extract energy. To overcome this limitation, we use wind-induced flutter vibration
Energy harvesting for self-powered aerostructure actuation
NASA Astrophysics Data System (ADS)
Bryant, Matthew; Pizzonia, Matthew; Mehallow, Michael; Garcia, Ephrahim
2014-04-01
This paper proposes and experimentally investigates applying piezoelectric energy harvesting devices driven by flow induced vibrations to create self-powered actuation of aerostructure surfaces such as tabs, flaps, spoilers, or morphing devices. Recently, we have investigated flow-induced vibrations and limit cycle oscillations due to aeroelastic flutter phenomena in piezoelectric structures as a mechanism to harvest energy from an ambient fluid flow. We will describe how our experimental investigations in a wind tunnel have demonstrated that this harvested energy can be stored and used on-demand to actuate a control surface such as a trailing edge flap in the airflow. This actuated control surface could take the form of a separate and discrete actuated flap, or could constitute rotating or deflecting the oscillating energy harvester itself to produce a non-zero mean angle of attack. Such a rotation of the energy harvester and the associated change in aerodynamic force is shown to influence the operating wind speed range of the device, its limit cycle oscillation (LCO) amplitude, and its harvested power output; hence creating a coupling between the device's performance as an energy harvester and as a control surface. Finally, the induced changes in the lift, pitching moment, and drag acting on a wing model are quantified and compared for a control surface equipped with an oscillating energy harvester and a traditional, static control surface of the same geometry. The results show that when operated in small amplitude LCO the energy harvester adds negligible aerodynamic drag.
Piezoelectric cantilevers energy harvesting in MEMS technique
NASA Astrophysics Data System (ADS)
Shang, Yingqi; Qiu, Chengjun; Liu, Hongmei; Chen, Xiaojie; Qu, Wei; Dou, Yanwei
2011-11-01
Piezoelectric cantilevers energy harvesting made by micro-electromechanical system (MEMS) technology can scavenge power from low-level ambient vibration sources. The developed cantilevers energy harvesting are featured with resonate frequency and power output in microwatt level, which is sufficient to the self-supportive sensors for in-service integrity monitoring of large social and environmental infrastructures at remote locations. In this paper, piezoelectric energy harvesting based on thick-film piezoelectric cantilevers is investigated to resonate at specific frequencies of an external vibration energy source, which creating electrical energy via the piezoelectric effect. Our cantilever device has a multiple structure with a proof mass added to the end. The thick film lead zirconate titanate Pb(Zr,Ti)O3 (PZT) coated on the top of Au/Cr/SiO2/Si substrates by sol-gel-spin method. The thickness of the PZT membrane was up to 2?m and the cantilevers substrates thickness 50?m, wideness 1.5mm, length 4mm. The Au/Ti top electrode is patterned on top of the sol-gel-spin coated PZT thick film in order to employ the d31 mode. The prototype energy generator has a measured performance of 0.74?W effective electrical power, and 4.93 DC output voltages to resistance load. The effect of proof mass, beam shape and damping on the power generating performance are modeled to provide a design guideline for maximum power harvesting from environmentally available low frequency vibrations. A multiple structure cantilever is designed to achieve compactness, low resonant frequency and minimum damping coefficient, simultaneously. This device is promising to support networks of ultra-low-power sensor.
Piezoelectric cantilevers energy harvesting in MEMS technique
NASA Astrophysics Data System (ADS)
Shang, Yingqi; Qiu, Chengjun; Liu, Hongmei; Chen, Xiaojie; Qu, Wei; Dou, Yanwei
2012-04-01
Piezoelectric cantilevers energy harvesting made by micro-electromechanical system (MEMS) technology can scavenge power from low-level ambient vibration sources. The developed cantilevers energy harvesting are featured with resonate frequency and power output in microwatt level, which is sufficient to the self-supportive sensors for in-service integrity monitoring of large social and environmental infrastructures at remote locations. In this paper, piezoelectric energy harvesting based on thick-film piezoelectric cantilevers is investigated to resonate at specific frequencies of an external vibration energy source, which creating electrical energy via the piezoelectric effect. Our cantilever device has a multiple structure with a proof mass added to the end. The thick film lead zirconate titanate Pb(Zr,Ti)O3 (PZT) coated on the top of Au/Cr/SiO2/Si substrates by sol-gel-spin method. The thickness of the PZT membrane was up to 2?m and the cantilevers substrates thickness 50?m, wideness 1.5mm, length 4mm. The Au/Ti top electrode is patterned on top of the sol-gel-spin coated PZT thick film in order to employ the d31 mode. The prototype energy generator has a measured performance of 0.74?W effective electrical power, and 4.93 DC output voltages to resistance load. The effect of proof mass, beam shape and damping on the power generating performance are modeled to provide a design guideline for maximum power harvesting from environmentally available low frequency vibrations. A multiple structure cantilever is designed to achieve compactness, low resonant frequency and minimum damping coefficient, simultaneously. This device is promising to support networks of ultra-low-power sensor.
Electrochemically driven mechanical energy harvesting.
Kim, Sangtae; Choi, Soon Ju; Zhao, Kejie; Yang, Hui; Gobbi, Giorgia; Zhang, Sulin; Li, Ju
2016-01-01
Efficient mechanical energy harvesters enable various wearable devices and auxiliary energy supply. Here we report a novel class of mechanical energy harvesters via stress-voltage coupling in electrochemically alloyed electrodes. The device consists of two identical Li-alloyed Si as electrodes, separated by electrolyte-soaked polymer membranes. Bending-induced asymmetric stresses generate chemical potential difference, driving lithium ion flux from the compressed to the tensed electrode to generate electrical current. Removing the bending reverses ion flux and electrical current. Our thermodynamic analysis reveals that the ideal energy-harvesting efficiency of this device is dictated by the Poisson's ratio of the electrodes. For the thin-film-based energy harvester used in this study, the device has achieved a generating capacity of 15%. The device demonstrates a practical use of stress-composition-voltage coupling in electrochemically active alloys to harvest low-grade mechanical energies from various low-frequency motions, such as everyday human activities. PMID:26733282
An electrostatic CMOS/BiCMOS Lithium ion vibration-based harvester-charger IC
NASA Astrophysics Data System (ADS)
Torres, Erick Omar
Self-powered microsystems, such as wireless transceiver microsensors, appeal to an expanding application space in monitoring, control, and diagnosis for commercial, industrial, military, space, and biomedical products. As these devices continue to shrink, their microscale dimensions allow them to be unobtrusive and economical, with the potential to operate from typically unreachable environments and, in wireless network applications, deploy numerous distributed sensing nodes simultaneously. Extended operational life, however, is difficult to achieve since their limited volume space constrains the stored energy available, even with state-of-the-art technologies, such as thin-film lithium-ion batteries (Li Ion) and micro-fuel cells. Harvesting ambient energy overcomes this deficit by continually replenishing the energy reservoir and, as a result, indefinitely extending system lifetime. In this work, an electrostatic harvester that harnesses ambient kinetic energy from vibrations to charge an energy-storage device (e.g., a battery) is investigated, developed, and evaluated. The proposed harvester charges and holds the voltage across a vibration-sensitive variable capacitor so that vibrations can induce it to generate current into the battery when capacitance decreases (as its plates separate). The challenge is that energy is harnessed at relatively slow rates, producing low output power, and the electronics required to transfer it to charge a battery can easily demand more than the power produced. To this end, the system reduces losses by time-managing and biasing its circuits to operate only when needed and with just enough energy while charging the capacitor through an efficient quasi-lossless inductor-based precharger. As result, the proposed energy harvester stores a net energy gain in the battery during every vibration cycle. Two energy-harvesting integrated circuits (IC) were analyzed, designed, developed, and validated using a 0.7-im BiCMOS process and a 30-Hz mechanical variable capacitor. The precharger, harvester, monitoring, and control microelectronics of the first prototype draw sufficient power to operate and at the same time produce experimentally 1.27, 2.14, and 2.87 nJ per vibration cycle for battery voltages at 2.7, 3.5, and 4.2 V, which with 30-Hz vibrations produce 38.1, 64.2, and 86.1 nW. By incorporating into the system a self-tuning loop that adapts optimally the inductor-based precharger to varying battery voltages, the second prototype harnessed and gained 1.93, 2.43, and 3.89 nJ per vibration cycle at battery voltages 2.7, 3.5, and 4.2 V, generating 57.89, 73.02, and 116.55 nW at 30 Hz. The harvester ultimately charges from 2.7 to 4.2 V a 1-muF capacitor (which emulates a small thin-film Li Ion) in approximately 69 s, harnessing in the same length of time 47.9% more energy than with a non-adapting harvester.
Piezomagnetoelastic broadband energy harvester: Nonlinear modeling and characterization
NASA Astrophysics Data System (ADS)
Aravind Kumar, K.; Ali, S. F.; Arockiarajan, A.
2015-11-01
Piezomagnetoelastic energy harvesters are one among the widely explored configurations to improve the broadband characteristics of vibration energy harvesters. Such nonlinear harvesters follow a Moon beam model with two magnets at the base and one at the tip of the beam. The present article develops a geometric nonlinear mathematical model for the broadband piezomagnetoelastic energy harvester. The electromechanical coupling and the nonlinear magnetic potential equations are developed from the dimensional system parameters to describe the nonlinear dynamics exhibited by the system. The developed model is capable of characterizing the monostable, bistable and tristable operating regimes of the piezomagnetoelastic energy harvester, which are not explicit in the Duffing representation of the system. Bifurcations and attractor motions are analyzed as nonlinear functions of the distance between base magnets and the field strength of the tip magnet. The model is further used to characterize the potential wells and stable states, with due focus on the performance of the system in broadband energy harvesting.
Energy harvesting wireless piezoelectric resonant force sensor
NASA Astrophysics Data System (ADS)
Ahmadi, Mehdi
The piezoelectric energy harvester has become a new powering option for some low-power electronic devices such as MEMS (Micro Electrical Mechanical System) sensors. Piezoelectric materials can collect the ambient vibrations energy and convert it to electrical energy. This thesis is intended to demonstrate the behavior of a piezoelectric energy harvester system at elevated temperature from room temperature up to 82°C, and compares the system's performance using different piezoelectric materials. The systems are structured with a Lead Magnesium Niobate-Lead Titanate (PMN-PT) single crystal patch bonded to an aluminum cantilever beam, Lead Indium Niobate-Lead Magnesium Niobate-Lead Titanate (PIN-PMN-PT) single crystal patch bonded to an aluminum cantilever beam and a bimorph cantilever beam which is made of Lead Zirconate Titanate (PZT). The results of this experimental study show the effects of the temperature on the operation frequency and output power of the piezoelectric energy harvesting system. The harvested electrical energy has been stored in storage circuits including a battery. Then, the stored energy has been used to power up the other part of the system, a wireless resonator force sensor, which uses frequency conversion techniques to convert the sensor's ultrasonic signal to a microwave signal in order to transmit the signal wirelessly.
Tree-inspired piezoelectric energy harvesting
NASA Astrophysics Data System (ADS)
Hobbs, William B.; Hu, David L.
2012-01-01
We design and test micro-watt energy-harvesters inspired by tree trunks swaying in the wind. A uniform flow vibrates a linear array of four cylinders affixed to piezoelectric energy transducers. Particular attention is paid to measuring the energy generated as a function of cylinder spacing, flow speed, and relative position of the cylinder within the array. Peak power is generated using cylinder center-to-center spacings of 3.3 diameters and flow speeds in which the vortex shedding frequency is 1.6 times the natural frequency of the cylinders. Using these flow speeds and spacings, the power generated by downstream cylinders can exceed that of leading cylinders by more than an order of magnitude. We visualize the flow in this system by studying the behavior of a dynamically matched flowing soap film with imbedded styrofoam disks. Our qualitative visualizations suggest that peak energy harvesting occurs under conditions in which vortices have fully detached from the leading cylinder.
Piezoelectric energy harvesting through shear mode operation
NASA Astrophysics Data System (ADS)
Malakooti, Mohammad H.; Sodano, Henry A.
2015-05-01
Piezoelectric materials are excellent candidates for use in energy harvesting applications due to their high electromechanical coupling properties that enable them to convert input mechanical energy into useful electric power. The electromechanical coupling coefficient of the piezoelectric material is one of the most significant parameters affecting energy conversion and is dependent on the piezoelectric mode of operation. In most piezoceramics, the d15 piezoelectric shear coefficient is the highest coefficient compared to the commonly used axial and transverse modes that utilize the d33 and the d31 piezoelectric strain coefficients. However, complicated electroding methods and challenges in evaluating the performance of energy harvesting devices operating in the shear mode have slowed research in this area. The shear deformation of a piezoelectric layer can be induced in a vibrating sandwich beam with a piezoelectric core. Here, a model based on Timoshenko beam theory is developed to predict the electric power output from a cantilever piezoelectric sandwich beam under base excitations. It is shown that the energy harvester operating in the shear mode is able to generate ?50% more power compared to the transverse mode for a numerical case study. Reduced models of both shear and transverse energy harvesters are obtained to determine the optimal load resistance in the system and perform an efficiency comparison between two models with fixed and adaptive resistances.
Harvesting Energy from Wastewater Treatment
Harvesting Energy from Wastewater Treatment Bruce Logan Penn State University #12;Energy Costs? 5-7% of electricity used in USA is for water &wastewater #12;Global Energy & Health IssuesGlobal Energy & Health content of WastewatersEnergy content of Wastewaters ·· ElectricityElectricity ""lostlost"" to water
Energy harvesting: a key to wireless sensor nodes
NASA Astrophysics Data System (ADS)
Bryant, Matthew; Garcia, Ephrahim
2009-07-01
Energy harvesting has enabled new operational concepts in the growing field of wireless sensing. A novel energy harvesting device driven by aeroelastic flutter vibrations has been developed and could be used to complement existing environmental energy harvesters such as solar cells in wireless sensing applications. An analytical model of the mechanical, electromechanical, and aerodynamic systems suitable for designing aeroelastic energy harvesters for various flow applications are derived and presented. Wind tunnel testing was performed with a prototype energy harvester to characterize the power output and flutter frequency response of the device over its entire range of operating wind speeds. Finally, two wing geometries, a flat plate and a NACA 0012 airfoil were tested and compared.
Energy-harvesting shock absorber with a mechanical motion rectifier
NASA Astrophysics Data System (ADS)
Li, Zhongjie; Zuo, Lei; Kuang, Jian; Luhrs, George
2013-02-01
Energy-harvesting shock absorbers are able to recover the energy otherwise dissipated in the suspension vibration while simultaneously suppressing the vibration induced by road roughness. They can work as a controllable damper as well as an energy generator. An innovative design of regenerative shock absorbers is proposed in this paper, with the advantage of significantly improving the energy harvesting efficiency and reducing the impact forces caused by oscillation. The key component is a unique motion mechanism, which we called ‘mechanical motion rectifier (MMR)’, to convert the oscillatory vibration into unidirectional rotation of the generator. An implementation of a MMR-based harvester with high compactness is introduced and prototyped. A dynamic model is created to analyze the general properties of the motion rectifier by making an analogy between mechanical systems and electrical circuits. The model is capable of analyzing electrical and mechanical components at the same time. Both simulation and experiments are carried out to verify the modeling and the advantages. The prototype achieved over 60% efficiency at high frequency, much better than conventional regenerative shock absorbers in oscillatory motion. Furthermore, road tests are done to demonstrate the feasibility of the MMR shock absorber, in which more than 15 Watts of electricity is harvested while driving at 15 mph on a smooth paved road. The MMR-based design can also be used for other applications of vibration energy harvesting, such as from tall buildings or long bridges.
Harvesting Energy from Wastewater Treatment
Harvesting Energy from Wastewater Treatment Bruce Logan Penn State University #12;Energy Costs? 5-7% of electricity used in USA is for water &wastewater #12;Global Energy & Health Issues 1 Billion people lack #12;Energy content of Wastewaters · Electricity "lost" to water and wastewater treatment= 0.6 quad
Implementation of a piezoelectric energy harvester in railway health monitoring
NASA Astrophysics Data System (ADS)
Li, Jingcheng; Jang, Shinae; Tang, Jiong
2014-03-01
With development of wireless sensor technology, wireless sensor network has shown a great potential for railway health monitoring. However, how to supply continuous power to the wireless sensor nodes is one of the critical issues in long-term full-scale deployment of the wireless smart sensors. Some energy harvesting methodologies have been available including solar, vibration, wind, etc; among them, vibration-based energy harvester using piezoelectric material showed the potential for converting ambient vibration energy to electric energy in railway health monitoring even for underground subway systems. However, the piezoelectric energy harvester has two major problems including that it could only generate small amount of energy, and that it should match the exact narrow band natural frequency with the excitation frequency. To overcome these problems, a wide band piezoelectric energy harvester, which could generate more power on various frequencies regions, has been designed and validated with experimental test. Then it was applied to a full-scale field test using actual railway train. The power generation of the wide band piezoelectric array has been compared to a narrow-band, resonant-based, piezoelectric energy harvester.
An innovative tri-directional broadband piezoelectric energy harvester
Su, Wei-Jiun Zu, Jean
2013-11-11
This paper presents a tri-directional piezoelectric energy harvester that is able to harvest vibration energy over a wide bandwidth from three orthogonal directions. The harvester consists of a main beam, an auxiliary beam, and a spring-mass system, with magnets integrated to introduce nonlinear force and couple the three sub-systems. Theoretical analysis and experiments were performed at constant acceleration under frequency sweeps to acquire frequency responses. The experimental results show that the voltage can achieve more than 2?V over more than 5?Hz of bandwidth with 1 M? load in the three orthogonal directions.
Spiral electrode d33 mode piezoelectric diaphragm combined with proof mass as energy harvester
NASA Astrophysics Data System (ADS)
Shen, Zhiyuan; Liu, Shuwei; Miao, Jianmin; Woh, Lye Sun; Wang, Zhihong
2015-03-01
The paper demonstrates an energy harvester using a freestanding piezoelectric diaphragm combined with a proof mass. The diaphragm bearing double-sided spiral electrodes makes use of the d33 piezoelectric effect to realize energy scavenging. The harvester was fabricated by using a MEMS technique. The energy converting performance of the diaphragm was characterized by a shaker system. Proof masses were combined at the center of the diaphragm to tune the resonance of the harvester for the sake of scavenging low frequency vibrational energy. A receptance model was built to explain the vibrational behavior of the combined system. The resonance tuning and energy harvesting performance of the combination system was experimentally verified.
Fast-Convergent Learning-aided Control in Energy Harvesting Networks Longbo Huang
Yao, Frances Foong
their actions. I. INTRODUCTION Recent developments in energy harvesting technologies make it possible harvesting technology has the potential to become a promising solution to energy problems in networks formed vibration into energy [4], [5]. Due to the capability in providing long lasting energy supply, the energy
NASA Astrophysics Data System (ADS)
Shiraishi, Takahisa; Kaneko, Noriyuki; Kurosawa, Minoru; Uchida, Hiroshi; Suzuki, Yasuhiro; Kobayashi, Takeshi; Funakubo, Hiroshi
2015-10-01
Energy-harvesting properties were investigated for the flexible piezoelectric devices, Pt/hydrothermally synthesized (K0.88Na0.12)NbO3/SrRuO3/metal foil, fabricated at low process temperatures below 300 °C. Fabricated devices had high flexibility, and cracking and peeling were not observed under the bending condition with the maximum curvature of 5.2 mm. The estimated Young’s modulus of the fabricated flexible devices was 37 GPa. The pulse poling treatment with AC voltage above 150 V enhanced the energy-harvesting properties. Although the dielectric constant was almost unchanged (?r = 120 at 200 Hz), the maximum output voltage measured at an acceleration of 10 m/s2 was observed at a resonance frequency of 126 Hz, and this voltage increased from 7.2 to 11 V after pulse poling treatment at 200 V. The maximum output power was 7.7 µW at a load resistance of 560 k?. The calculated Q and K2 values were 30 and 0.0014, respectively. The power density was 1.8 µW/(G2·mm3), which is higher than the previous reports for films and sintered bodies of (KxNa1-x) fabricated above 500 °C.
Review of the application of energy harvesting in buildings
NASA Astrophysics Data System (ADS)
Matiko, J. W.; Grabham, N. J.; Beeby, S. P.; Tudor, M. J.
2014-01-01
This review presents the state of the art of the application of energy harvesting in commercial and residential buildings. Electromagnetic (optical and radio frequency), kinetic, thermal and airflow-based energy sources are identified as potential energy sources within buildings and the available energy is measured in a range of buildings. Suitable energy harvesters are discussed and the available and the potential harvested energy calculated. Calculations based on these measurements, and the technical specifications of state-of-the-art harvesters, show that typical harvested powers are: (1) indoor solar cell (active area of 9 cm2, volume of 2.88 cm3): ˜300 µW from a light intensity of 1000 lx; (2) thermoelectric harvester (volume of 1.4 cm3): 6 mW from a thermal gradient of 25 °C (3) periodic kinetic energy harvester (volume of 0.15 cm3): 2 µW from a vibration acceleration of 0.25 m s-2 at 45 Hz (4) electromagnetic wave harvester (13 cm antenna length and conversion efficiency of 0.7): 1 µW with an RF source power of -25 dBm; and (5) airflow harvester (wind turbine blade of 6 cm diameter and generator efficiency of 0.41): 140 mW from an airflow of 8 m s-1. These results highlight the high potential of energy harvesting technology in buildings and the relative attractions of various harvester technologies. The harvested power could either be used to replace batteries or to prolong the life of rechargeable batteries for low-power (˜1 mW) electronic devices.
Flow energy piezoelectric bimorph nozzle harvester
NASA Astrophysics Data System (ADS)
Sherrit, Stewart; Lee, Hyeong Jae; Walkemeyer, Phillip; Hasenoehrl, Jennifer; Hall, Jeffrey L.; Colonius, Tim; Tosi, Luis Phillipe; Arrazola, Alvaro; Kim, Namhyo; Sun, Kai; Corbett, Gary
2014-04-01
There is a need for a long-life power generation scheme that could be used downhole in an oil well to produce 1 Watt average power. There are a variety of existing or proposed energy harvesting schemes that could be used in this environment but each of these has its own limitations. The vibrating piezoelectric structure is in principle capable of operating for very long lifetimes (decades) thereby possibly overcoming a principle limitation of existing technology based on rotating turbo-machinery. In order to determine the feasibility of using piezoelectrics to produce suitable flow energy harvesting, we surveyed experimentally a variety of nozzle configurations that could be used to excite a vibrating piezoelectric structure in such a way as to enable conversion of flow energy into useful amounts of electrical power. These included reed structures, spring mass-structures, drag and lift bluff bodies and a variety of nozzles with varying flow profiles. Although not an exhaustive survey we identified a spline nozzle/piezoelectric bimorph system that experimentally produced up to 3.4 mW per bimorph. This paper will discuss these results and present our initial analyses of the device using dimensional analysis and constitutive electromechanical modeling. The analysis suggests that an order-of-magnitude improvement in power generation from the current design is possible.
A Hip Implant Energy Harvester
NASA Astrophysics Data System (ADS)
Pancharoen, K.; Zhu, D.; Beeby, S. P.
2014-11-01
This paper presents a kinetic energy harvester designed to be embedded in a hip implant which aims to operate at a low frequency associated with body motion of patients. The prototype is designed based on the constrained volume available in a hip prosthesis and the challenge is to harvest energy from low frequency movements (< 1 Hz) which is an average frequency during free walking of a patient. The concept of magnetic-force-driven energy harvesting is applied to this prototype considering the hip movements during routine activities of patients. The magnetic field within the harvester was simulated using COMSOL. The simulated resonant frequency was around 30 Hz and the voltage induced in a coil was predicted to be 47.8 mV. A prototype of the energy harvester was fabricated and tested. A maximum open circuit voltage of 39.43 mV was obtained and the resonant frequency of 28 Hz was observed. Moreover, the power output of 0.96 ?W was achieved with an optimum resistive load of 250?.
Optimal Sleep-Wake Scheduling for Energy Harvesting Smart Mobile Devices
Huang, Longbo
harvesting technologies can likely be a remedy for the poor battery performance of the smart devices], by converting mechanical vibration into energy [4], or by using solar panels [5]. These newly developed energy
Bilgen, Onur; Kenerson, John G; Akpinar-Elci, Muge; Hattery, Rebecca; Hanson, Lisbet M
2015-08-01
The World Health Organization has established recommendations for blood pressure measurement devices for use in low-resource venues, setting the "triple A" expectations of Accuracy, Affordability, and Availability. Because of issues related to training and assessment of proficiency, the pendulum has swung away from manual blood pressure devices and auscultatory techniques towards automatic oscillometric devices. As a result of power challenges in the developing world, there has also been a push towards semiautomatic devices that are not dependent on external power sources or batteries. Beyond solar solutions, disruptive technology related to solid-state vibrational energy harvesting may be the next iterative solution to attain the ultimate goal of a self-powered low-cost validated device that is simple to use and reliable. PMID:25913774
NASA Astrophysics Data System (ADS)
Liu, W. Q.; Badel, A.; Formosa, F.; Wu, Y. P.; Agbossou, A.
2013-12-01
The challenge of variable vibration frequencies for energy harvesting calls for the development of wideband energy harvesters. Bistability has been proven to be a potential solution. Optimization of the energy extraction is another important objective for energy harvesting. Nonlinear synchronized switching techniques have demonstrated some of the best performances. This paper presents a novel energy harvesting solution which combines these two techniques: the OSECE (optimized synchronous electric charge extraction) technique is used along with a BSM (buckled-spring-mass) bistable generator to achieve wideband energy harvesting. The effect of the electromechanical coupling coefficient on the harvested power for the bistable harvester with the nonlinear energy extraction technique is discussed for the first time. The performances of the proposed solution for different levels of electromechanical coupling coefficients in the cases of chirp and noise excitations are compared against the performances of the bistable harvester with the standard technique. It is shown that the OSECE technique is a much better option for wideband energy harvesting than the standard circuit. Moreover, the harvested energy is drastically increased for all excitations in the case of low electromechanical coupling coefficients. When the electromechanical coupling coefficient is high, the performance of the OSECE technique is not as good as the standard circuit for forward sweeps, but superior for the reverse sweep and band-limited noise cases. However, considering that real excitation signals are more similar to noise signals, the OSECE technique enhances the performance.
An electromechanical finite element model for piezoelectric energy harvester plates
NASA Astrophysics Data System (ADS)
De Marqui Junior, Carlos; Erturk, Alper; Inman, Daniel J.
2009-10-01
Vibration-based energy harvesting has been investigated by several researchers over the last decade. The goal in this research field is to power small electronic components by converting the waste vibration energy available in their environment into electrical energy. Recent literature shows that piezoelectric transduction has received the most attention for vibration-to-electricity conversion. In practice, cantilevered beams and plates with piezoceramic layers are employed as piezoelectric energy harvesters. The existing piezoelectric energy harvester models are beam-type lumped parameter, approximate distributed parameter and analytical distributed parameter solutions. However, aspect ratios of piezoelectric energy harvesters in several cases are plate-like and predicting the power output to general (symmetric and asymmetric) excitations requires a plate-type formulation which has not been covered in the energy harvesting literature. In this paper, an electromechanically coupled finite element (FE) plate model is presented for predicting the electrical power output of piezoelectric energy harvester plates. Generalized Hamilton's principle for electroelastic bodies is reviewed and the FE model is derived based on the Kirchhoff plate assumptions as typical piezoelectric energy harvesters are thin structures. Presence of conductive electrodes is taken into account in the FE model. The predictions of the FE model are verified against the analytical solution for a unimorph cantilever and then against the experimental and analytical results of a bimorph cantilever with a tip mass reported in the literature. Finally, an optimization problem is solved where the aluminum wing spar of an unmanned air vehicle (UAV) is modified to obtain a generator spar by embedding piezoceramics for the maximum electrical power without exceeding a prescribed mass addition limit.
Effect of boundary conditions on piezoelectric buckled beams for vibrational noise harvesting
NASA Astrophysics Data System (ADS)
Cottone, F.; Mattarelli, M.; Vocca, H.; Gammaitoni, L.
2015-11-01
Nonlinear bistable systems have proven to be advantageous for energy harvesting of random and real ambient vibrations. One simple way of implementing a bistable transducer is setting a piezoelectric beam in a post-buckled configuration by axial compression. Besides, hinged or clamped-clamped type of boundary conditions correspond to two different post-buckled shape functions. Here we study, through theoretical analysis and numerical simulations, the efficiency of a hinged and clamped-clamped piezoelectric bridge under band-limited random noise with progressive axial load. Clamped configuration results to harvest 26% more power than hinged around an optimal axial load of 0.05%, while, in the intra-well trapped situation, above 0.1%, the two configurations present no substantial difference. Nevertheless, simulations confirm the advantage of exploiting inter-well oscillations in bistable regime.
Harvesting ultrasonic energy using 1-3 piezoelectric composites
NASA Astrophysics Data System (ADS)
Yang, Zengtao; Zeng, Deping; Wang, Hua; Zhao, Chunliang; Tan, Jianwen
2015-07-01
Harvesting longitudinal ultrasonic energy from the surroundings has been highlighted as an alternative to conventional batteries. The energy can be used to power portable electronics and wireless sensors operating at remote locations. In this paper, an ultrasonic energy harvester made of a 1-3 piezoelectric composite is proposed. This harvester could convert longitudinal-mode ultrasonic vibrations into electrical energy. A theoretical analysis of a 1-3 piezoelectric composite harvester operating with thickness-stretch modes is performed. The results show that maximum output power dissipated in the load can be achieved when the load resistor is equal to the impedance of the harvester. Under such conditions, two peaks of maximum output power occur at the antiresonance frequency and resonance frequency. An experimental study following the theoretical model confirms the feasibility of extracting certain amounts of ultrasonic vibration energy using a 1-3 piezoelectric composite harvester. Both the experimental and theoretical studies show that the output voltages for different pure resistive loads peak at different operating frequencies. As the pure resistive load increases, the operating frequency varies from the resonance frequency to the antiresonance frequency.
Cantilever piezoelectric energy harvester with multiple cavities
NASA Astrophysics Data System (ADS)
Srinivasulu Raju, S.; Umapathy, M.; Uma, G.
2015-11-01
Energy harvesting employing piezoelectric materials in mechanical structures such as cantilever beams, plates, diaphragms, etc, has been an emerging area of research in recent years. The research in this area is also focused on structural tailoring to improve the harvested power from the energy harvesters. Towards this aim, this paper presents a method for improving the harvested power from a cantilever piezoelectric energy harvester by introducing multiple rectangular cavities. A generalized model for a piezoelectric energy harvester with multiple rectangular cavities at a single section and two sections is developed. A method is suggested to optimize the thickness of the cavities and the number of cavities required to generate a higher output voltage for a given cantilever beam structure. The performance of the optimized energy harvesters is evaluated analytically and through experimentation. The simulation and experimental results show that the performance of the energy harvester can be increased with multiple cavities compared to the harvester with a single cavity.
Energy harvesting in the nonlinear electromagnetic system
NASA Astrophysics Data System (ADS)
Kucab, K.; Górski, G.; Mizia, J.
2015-11-01
We examine the electrical response of electromagnetic device working both in the linear and nonlinear domain. The harvester is consisted of small magnet moving in isolating tube surrounded by the coil attached to the electrical circuit. In the nonlinear case the magnet vibrates in between two fixed magnets attached to the both ends of the tube. Additionally we use two springs which limit the movement of the small magnet. The linear case is when the moving magnet is attached to the repelling springs, and the static magnets have been replaced by the non-magnetic material. The potentials and forces were calculated using both the analytical expressions and the finite elements method. We compare the results for energy harvesting obtained in these two cases. The generated output power in the linear case reaches the peak value 80 mW near the resonance frequency ?0 for maximum base acceleration considered by us, whereas in the non-linear case the corresponding outpot power has the peak value 95 mW and additionally relatively high values in the excitation frequencies range up to ? = 1.2?0. The numerical results also show that the power efficiency in the nonlinear case exceeds the corresponding efficiency in the linear case at relatively high values of base accelerations greater than 5 g. The results show the increase of harvested energy in the broad band of excitation frequencies in the nonlinear case.
Energy harvesting devices for harvesting energy from terahertz electromagnetic radiation
Novack, Steven D.; Kotter, Dale K.; Pinhero, Patrick J.
2012-10-09
Methods, devices and systems for harvesting energy from electromagnetic radiation are provided including harvesting energy from electromagnetic radiation. In one embodiment, a device includes a substrate and one or more resonance elements disposed in or on the substrate. The resonance elements are configured to have a resonant frequency, for example, in at least one of the infrared, near-infrared and visible light spectra. A layer of conductive material may be disposed over a portion of the substrate to form a ground plane. An optical resonance gap or stand-off layer may be formed between the resonance elements and the ground plane. The optical resonance gap extends a distance between the resonance elements and the layer of conductive material approximately one-quarter wavelength of a wavelength of the at least one resonance element's resonant frequency. At least one energy transfer element may be associated with the at least one resonance element.
SCANNING THE ISSUE Energy Harvesting and
Tentzeris, Manos
Editor I. SCANNING THE ISSUE Energy-harvesting technologies are fundamental in enabling the realization in extremely rugged environments. This power autonomy through the harvesting of ambient ``green'' energy wouldSCANNING THE ISSUE Energy Harvesting and Scavenging By MANOS M. TENTZERIS, Fellow, IEEE Guest
Mechanical vibration to electrical energy converter
Kellogg, Rick Allen (Tijeras, NM); Brotz, Jay Kristoffer (Albuquerque, NM)
2009-03-03
Electromechanical devices that generate an electrical signal in response to an external source of mechanical vibrations can operate as a sensor of vibrations and as an energy harvester for converting mechanical vibration to electrical energy. The devices incorporate a magnet that is movable through a gap in a ferromagnetic circuit, wherein a coil is wound around a portion of the ferromagnetic circuit. A flexible coupling is used to attach the magnet to a frame for providing alignment of the magnet as it moves or oscillates through the gap in the ferromagnetic circuit. The motion of the magnet can be constrained to occur within a substantially linear range of magnetostatic force that develops due to the motion of the magnet. The devices can have ferromagnetic circuits with multiple arms, an array of magnets having alternating polarity and, encompass micro-electromechanical (MEM) devices.
Enhanced aeroelastic energy harvesting with a beam stiffener
NASA Astrophysics Data System (ADS)
Zhao, Liya; Yang, Yaowen
2015-03-01
In this article, we propose an easy but quite effective method to significantly enhance the power generation capability of an aeroelastic energy harvester. The method is to attach a beam stiffener to the substrate of the harvester, which works as an electromechanical coupling magnifier. It is shown to be effective for all three considered types of harvesters based on galloping, vortex-induced vibration and flutter, leading to a superior performance over the conventional designs without the beam stiffener, with dozens of times the increase in power and an almost 100% increase in the power extraction efficiency yet with comparable or even smaller transverse displacement. Choice guidelines of optimal types of energy harvesters are also suggested based on the given wind situations where the electronic device is located.
POWER EVALUATION FOR FLUTTER-BASED ELECTROMAGNETIC ENERGY HARVESTER USING CFD SIMULATIONS
Stanford University
POWER EVALUATION FOR FLUTTER-BASED ELECTROMAGNETIC ENERGY HARVESTER USING CFD SIMULATIONS J. Park1 also been proposed as an input source for energy harvesters. Flutter vibration of a T-shape cantilever by self exciting aerodynamic forces (flutter) can be used as an effective input source for small scale
Energy Harvesting for Aerospace Structural Health Monitoring Systems
NASA Astrophysics Data System (ADS)
Pearson, M. R.; Eaton, M. J.; Pullin, R.; Featherston, C. A.; Holford, K. M.
2012-08-01
Recent research into damage detection methodologies, embedded sensors, wireless data transmission and energy harvesting in aerospace environments has meant that autonomous structural health monitoring (SHM) systems are becoming a real possibility. The most promising system would utilise wireless sensor nodes that are able to make decisions on damage and communicate this wirelessly to a central base station. Although such a system shows great potential and both passive and active monitoring techniques exist for detecting damage in structures, powering such wireless sensors nodes poses a problem. Two such energy sources that could be harvested in abundance on an aircraft are vibration and thermal gradients. Piezoelectric transducers mounted to the surface of a structure can be utilised to generate power from a dynamic strain whilst thermoelectric generators (TEG) can be used to generate power from thermal gradients. This paper reports on the viability of these two energy sources for powering a wireless SHM system from vibrations ranging from 20 to 400Hz and thermal gradients up to 50°C. Investigations showed that using a single vibrational energy harvester raw power levels of up to 1mW could be generated. Further numerical modelling demonstrated that by optimising the position and orientation of the vibrational harvester greater levels of power could be achieved. However using commercial TEGs average power levels over a flight period between 5 to 30mW could be generated. Both of these energy harvesting techniques show a great potential in powering current wireless SHM systems where depending on the complexity the power requirements range from 1 to 180mW.
Principles of thermoacoustic energy harvesting
NASA Astrophysics Data System (ADS)
Avent, A. W.; Bowen, C. R.
2015-11-01
Thermoacoustics exploit a temperature gradient to produce powerful acoustic pressure waves. The technology has a key role to play in energy harvesting systems. A time-line in the development of thermoacoustics is presented from its earliest recorded example in glass blowing through to the development of the Sondhauss and Rijke tubes to Stirling engines and pulse-tube cryo-cooling. The review sets the current literature in context, identifies key publications and promising areas of research. The fundamental principles of thermoacoustic phenomena are explained; design challenges and factors influencing efficiency are explored. Thermoacoustic processes involve complex multi-physical coupling and transient, highly non-linear relationships which are computationally expensive to model; appropriate numerical modelling techniques and options for analyses are presented. Potential methods of harvesting the energy in the acoustic waves are also examined.
Energy Harvesting Broadcast Channel with Inefficient Energy Storage
Yener, Aylin
Energy Harvesting Broadcast Channel with Inefficient Energy Storage Kaya Tutuncuoglu Aylin Yener with an energy harvesting transmitter equipped with an inefficient energy storage device. For this setting by the energy harvesting process. The convexity of the capacity region for the energy harvesting broadcast
Energy harvesting from low frequency applications using piezoelectric materials
Li, Huidong; Tian, Chuan; Deng, Z. Daniel
2014-12-15
In an effort to eliminate the replacement of the batteries of electronic devices that are difficult or impractical to service once deployed, harvesting energy from mechanical vibrations or impacts using piezoelectric materials has been researched over the last several decades. However, a majority of these applications have very low input frequencies. This presents a challenge for the researchers to optimize the energy output of piezoelectric energy harvesters, due to the relatively high elastic moduli of piezoelectric materials used to date. This paper reviews the current state of research on piezoelectric energy harvesting devices for low frequency (0–100?Hz) applications and the methods that have been developed to improve the power outputs of the piezoelectric energy harvesters. Various key aspects that contribute to the overall performance of a piezoelectric energy harvester are discussed, including geometries of the piezoelectric element, types of piezoelectric material used, techniques employed to match the resonance frequency of the piezoelectric element to input frequency of the host structure, and electronic circuits specifically designed for energy harvesters.
Experimental investigation of fatigue in a cantilever energy harvesting beam
NASA Astrophysics Data System (ADS)
Avvari, Panduranga Vittal; Yang, Yaowen; Liu, Peiwen; Soh, Chee Kiong
2015-03-01
Over the last decade, cantilever energy harvesters gained immense popularity owing to the simplicity of the design and piezoelectric energy harvesting (PEH) using the cantilever design has undergone considerable evolution. The major drawback of a vibrating cantilever beam is its vulnerability to fatigue over a period of time. This article brings forth an experimental investigation into the phenomenon of fatigue of a PEH cantilever beam. As there has been very little literature reported in this area, an effort has been made to scrutinize the damage due to fatigue in a linear vibrating cantilever PEH beam consisting of an aluminum substrate with a piezoelectric macro-fiber composite (MFC) patch attached near the root of the beam and a tip mass attached to the beam. The beam was subjected to transverse vibrations and the behavior of the open circuit voltage was recorded with passing time. Moreover, electro-mechanical admittance readings were obtained periodically using the same MFC patch as a Structural health monitoring (SHM) sensor to assess the health of the PEH beam. The results show that with passing time the PEH beam underwent fatigue in both the substrate and MFC, which is observed in a complimentary trend in the voltage and admittance readings. The claim is further supported using the variation of root mean square deviation (RMSD) of the real part of admittance (conductance) readings. Thus, this study concludes that the fatigue issue should be addressed in the design of PEH for long term vibration energy harvesting.
Power management for energy harvesting wireless sensors
NASA Astrophysics Data System (ADS)
Arms, S. W.; Townsend, C. P.; Churchill, D. L.; Galbreath, J. H.; Mundell, S. W.
2005-05-01
The objective of this work was to demonstrate smart wireless sensing nodes capable of operation at extremely low power levels. These systems were designed to be compatible with energy harvesting systems using piezoelectric materials and/or solar cells. The wireless sensing nodes included a microprocessor, on-board memory, sensing means (1000 ohm foil strain gauge), sensor signal conditioning, 2.4 GHz IEEE 802.15.4 radio transceiver, and rechargeable battery. Extremely low power consumption sleep currents combined with periodic, timed wake-up was used to minimize the average power consumption. Furthermore, we deployed pulsed sensor excitation and microprocessor power control of the signal conditioning elements to minimize the sensors" average contribution to power draw. By sleeping in between samples, we were able to demonstrate extremely low average power consumption. At 10 Hz, current consumption was 300 microamps at 3 VDC (900 microwatts); at 5 Hz: 400 microwatts, at 1 Hz: 90 microwatts. When the RF stage was not used, but data were logged to memory, consumption was further reduced. Piezoelectric strain energy harvesting systems delivered ~2000 microwatts under low level vibration conditions. Output power levels were also measured from two miniature solar cells; which provided a wide range of output power (~100 to 1400 microwatts), depending on the light type & distance from the source. In summary, system power consumption may be reduced by: 1) removing the load from the energy harvesting & storage elements while charging, 2) by using sleep modes in between samples, 3) pulsing excitation to the sensing and signal conditioning elements in between samples, and 4) by recording and/or averaging, rather than frequently transmitting, sensor data.
Fluidic energy harvesting beams in grid turbulence
NASA Astrophysics Data System (ADS)
Danesh-Yazdi, A. H.; Goushcha, O.; Elvin, N.; Andreopoulos, Y.
2015-08-01
Much of the recent research involving fluidic energy harvesters based on piezoelectricity has focused on excitation through vortex-induced vibration while turbulence-induced excitation has attracted very little attention, and virtually no previous work exists on excitation due to grid-generated turbulence. The present experiments involve placing several piezoelectric cantilever beams of various dimensions and properties in flows where turbulence is generated by passive, active, or semi-passive grids, the latter having a novel design that significantly improves turbulence generation compared to the passive grid and is much less complex than the active grid. We experimentally show for the first time that the average power harvested by a piezoelectric cantilever beam placed in decaying isotropic, homogeneous turbulence depends on mean velocity, velocity and length scales of turbulence as well as the electromechanical properties of the beam. The output power can be modeled as a power law with respect to the distance of the beam from the grid. Furthermore, we show that the rate of decay of this power law closely follows the rate of decay of the turbulent kinetic energy. We also introduce a forcing function used to model approximately the turbulent eddies moving over the cantilever beam and observe that the feedback from the beam motion onto the flow is virtually negligible for most of the cases considered, indicating an effectively one-way interaction for small-velocity fluctuations.
Dual-phase self-biased magnetoelectric energy harvester
NASA Astrophysics Data System (ADS)
Zhou, Yuan; Apo, Daniel J.; Priya, Shashank
2013-11-01
We report a magnetoelectric energy harvester structure that can simultaneously scavenge magnetic and vibration energy in the absence of DC magnetic field. The structure consisted of a piezoelectric macro-fiber composite bonded to a Ni cantilever. Large magnetoelectric coefficient ˜50 V/cm Oe and power density ˜4.5 mW/cm3 (1 g acceleration) were observed at the resonance frequency. An additive effect was realized when the harvester operated under dual-phase mode. The increase in voltage output at the first three resonance frequencies under dual-phase mode was found to be 2.4%, 35.5%, and 360.7%. These results present significant advancement toward high energy density multimode energy harvesting system.
NASA Astrophysics Data System (ADS)
Durou, Hugo; Rossi, Carole; Brunet, Magali; Vanhecke, Claude; Bailly, Nicolas; Ardila, Gustavo; Ourak, Lamine; Ramond, Adrien; Simon, Patrice; Taberna, Pierre-Louis
2008-12-01
Vibration harvesting has been intensively developed recently and systems have been simulated and realized, but real-life situations (including aircraft Structure Health Monitoring (SHM)involve uneven, low amplitude, low frequency vibrations. In such an unfavorable case, it is very likely that no power can be harvested for a long time. To overcome this, multi-source harvesting is a relevant solution, and in our application both solar and thermal gradient sources are available. We propose in this paper a complete Microsystem including a piezoelectric vibration harvesting module, thermoelectric conversion module, signal processing electronics and supercapacitor. A model is proposed for these elements and a VHDL-AMS simulation of the whole system is presented, showing that the vibration harvesting device alone cannot supply properly a SHM wireless node. Its role is nevertheless important since it is a more reliable source than thermoelectric (which depends on climatic conditions). Moreover, synergies between vibration harvesting and thermoelectric scavenging circuits are presented.
Impact-induced high-energy orbits of nonlinear energy harvesters
NASA Astrophysics Data System (ADS)
Zhou, Shengxi; Cao, Junyi; Inman, Daniel J.; Liu, Shengsheng; Wang, Wei; Lin, Jing
2015-03-01
This letter presents an impact-induced method for nonlinear energy harvesters to obtain high-energy orbits over a wide frequency range under low excitation levels. Based on the impact principle and conservation of momentum, nonlinear electromechanical equations are derived to describe the system response due to initial impacts. Numerical and experimental results show that nonlinear bistable and tristable harvesters can sustain large-amplitude interwell oscillations over a wide range of frequencies, by achieving high-energy orbits in the beginning induced by an initial impact. The proposed impact-induced method could facilitate to efficient energy harvesting from low level ambient vibrations.
Energy harvesting from controlled buckling of piezoelectric beams
NASA Astrophysics Data System (ADS)
Ansari, M. H.; Karami, M. Amin
2015-11-01
A piezoelectric vibration energy harvester is presented that can generate electricity from the weight of passing cars or crowds. The energy harvester consists of a piezoelectric beam, which buckles when the device is stepped on. The energy harvester can have a horizontal or vertical configuration. In the vertical (direct) configuration, the piezoelectric beam is vertical and directly sustains the weight of the vehicles or people. In the horizontal (indirect) configuration, the vertical weight is transferred to a horizontal axial force through a scissor-like mechanism. Buckling of the beam results in significant stresses and, thus, large power production. However, if the beam’s buckling is not controlled, the beam will fracture. To prevent this, the axial deformation is constrained to limit the deformations of the beam. In this paper, the energy harvester is analytically modeled. The considered piezoelectric beam is a general non-uniform beam. The natural frequencies, mode shapes, and the critical buckling force corresponding to each mode shape are calculated. The electro-mechanical coupling and the geometric nonlinearities are included in the model. The design criteria for the device are discussed. It is demonstrated that a device, realized with commonly used piezoelectric patches, can generate tens of milliwatts of power from passing car traffic. The proposed device could also be implemented in the sidewalks or integrated in shoe soles for energy generation. One of the key features of the device is its frequency up-conversion characteristics. The piezoelectric beam undergoes free vibrations each time the weight is applied to or removed from the energy harvester. The frequency of the free vibrations is orders of magnitude larger than the frequency of the load. The device is, thus, both efficient and insensitive to the frequency of the force excitations.
Piezoelectric Energy Harvesting in Internal Fluid Flow
Lee, Hyeong Jae; Sherrit, Stewart; Tosi, Luis Phillipe; Walkemeyer, Phillip; Colonius, Tim
2015-01-01
We consider piezoelectric flow energy harvesting in an internal flow environment with the ultimate goal powering systems such as sensors in deep oil well applications. Fluid motion is coupled to structural vibration via a cantilever beam placed in a converging-diverging flow channel. Two designs were considered for the electromechanical coupling: first; the cantilever itself is a piezoelectric bimorph; second; the cantilever is mounted on a pair of flextensional actuators. We experimentally investigated varying the geometry of the flow passage and the flow rate. Experimental results revealed that the power generated from both designs was similar; producing as much as 20 mW at a flow rate of 20 L/min. The bimorph designs were prone to failure at the extremes of flow rates tested. Finite element analysis (FEA) showed fatigue failure was imminent due to stress concentrations near the bimorph’s clamped region; and that robustness could be improved with a stepped-joint mounting design. A similar FEA model showed the flextensional-based harvester had a resonant frequency of around 375 Hz and an electromechanical coupling of 0.23 between the cantilever and flextensional actuators in a vacuum. These values; along with the power levels demonstrated; are significant steps toward building a system design that can eventually deliver power in the Watts range to devices down within a well. PMID:26473879
Piezoelectric Energy Harvesting in Internal Fluid Flow.
Lee, Hyeong Jae; Sherrit, Stewart; Tosi, Luis Phillipe; Walkemeyer, Phillip; Colonius, Tim
2015-01-01
We consider piezoelectric flow energy harvesting in an internal flow environment with the ultimate goal powering systems such as sensors in deep oil well applications. Fluid motion is coupled to structural vibration via a cantilever beam placed in a converging-diverging flow channel. Two designs were considered for the electromechanical coupling: first; the cantilever itself is a piezoelectric bimorph; second; the cantilever is mounted on a pair of flextensional actuators. We experimentally investigated varying the geometry of the flow passage and the flow rate. Experimental results revealed that the power generated from both designs was similar; producing as much as 20 mW at a flow rate of 20 L/min. The bimorph designs were prone to failure at the extremes of flow rates tested. Finite element analysis (FEA) showed fatigue failure was imminent due to stress concentrations near the bimorph's clamped region; and that robustness could be improved with a stepped-joint mounting design. A similar FEA model showed the flextensional-based harvester had a resonant frequency of around 375 Hz and an electromechanical coupling of 0.23 between the cantilever and flextensional actuators in a vacuum. These values; along with the power levels demonstrated; are significant steps toward building a system design that can eventually deliver power in the Watts range to devices down within a well. PMID:26473879
Tunable bistable devices for harvesting energy from spinning wheels
NASA Astrophysics Data System (ADS)
Elhadidi, Mohamed; Helal, Mohammed; Nassar, Omar; Arafa, Mustafa; Zeyada, Yasser
2015-04-01
Bistable systems have recently been employed for vibration energy harvesting owing to their favorable dynamic characteristics and desirable response for wideband excitation. In this paper, we investigate the use of bistable harvesters to extract energy from spinning wheels. The proposed harvester consists of a piezoelectric cantilever beam that is mounted on a rigid spinning hub and carries a tip mass in the form of a permanent magnet. Magnetic repulsion forces from an opposite magnet cause the beam to possess two stable equilibrium positions. Inter-well lead-lag oscillations caused by rotation in a vertical plane provide a good source for energy extraction. The design offers frequency tuning, as the centrifugal forces strain the harvester, thereby increasing its natural frequency to cope with a variable rotational speed. This has applications in self-powered sensors mounted on spinning wheels, such as tire pressure monitoring sensors. An effort is made to select the design parameters to enable the harvester to exhibit favorable inter-well oscillations across a range of rotational speeds for enhanced energy harvesting. Findings of the present work are verified both numerically and experimentally.
Fabrication and testing of an energy-harvesting hydraulic damper
NASA Astrophysics Data System (ADS)
Li, Chuan; Tse, Peter W.
2013-06-01
Hydraulic dampers are widely used to dissipate energy during vibration damping. In this paper, an energy-harvesting hydraulic damper is proposed for collecting energy while simultaneously damping vibration. Under vibratory excitation, the flow of hydraulic oil inside the cylinder of the damper is converted into amplified rotation via a hydraulic motor, whose output shaft is connected to an electromagnetic generator capable of harvesting a large amount of energy. In this way, the vibration is damped by both oil viscosity and the operation of an electrical mechanism. An electromechanical model is presented to illustrate both the electrical and mechanical responses of the system. A three-stage identification approach is introduced to facilitate the model parameter identification using cycle-loading experiments. A prototype device is developed and characterized in a test rig. The maximum power harvested during the experiments was 435.1 W (m s-1)-1, using a predefined harmonic excitation with an amplitude of 0.02 m, a frequency of 0.8 Hz, and an optimal resistance of 2 ?. Comparison of the experimental and computational results confirmed the effectiveness of both the electromechanical model and the three-stage identification approach in realizing the proposed design.
Vibration-to-electric energy conversion using a mechanically-varied capacitor
Yen, Bernard Chih-Hsun, 1981-
2005-01-01
Past research in vibration energy harvesting has focused on the use of variable capacitors, magnets, or piezoelectric materials as the basis of energy transduction. How- ever, few of these studies have explored the detailed ...
Design and Experimentation of a Wireless Sensor Network Node Powered by Vibration Energy
1 Design and Experimentation of a Wireless Sensor Network Node Powered by Vibration Energy Yek Hong consumption and provides a low cost solution for the application of detecting vibrations. While harvesting to be interpreted into vibration measurements, thus we have a simple and yet elegant design. In order to prove
Investigations of biomimetic light energy harvesting pigments
Van Patten, P.G.; Donohoe, R.J.; Lindsey, J.S.; Bocian, D.F.
1998-12-01
This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Nature uses chlorophyll and other porphyrinic pigments to capture and transfer light energy as a preliminary step in photosynthesis. The design of synthetic assemblies of light harvesting and energy directing pigments has been explored through synthesis and characterization of porphyrin oligomers. In this project, pigment electronic and vibrational structures have been explored by electrochemistry and dynamic and static optical measurements. Transient absorption data reveal energy transfer between pigments with lifetimes on the order of 20--200 picoseconds, while Raman data reveal that the basic porphyrin core structure is unperturbed relative to the individual monomer units. These two findings, along with an extensive series of experiments on the oxidized oligomers, reveal that coupling between the pigments is fundamentally weak, but sufficient to allow facile energy transfer as the predominant excited state process. Modeling of the expected quantum yields for energy transfer within a variety of arrays was accomplished, thereby providing a tool to guide synthetic goals.
Solar/Electromagnetic Energy Harvesting and Wireless
Tentzeris, Manos
INVITED P A P E R Solar/Electromagnetic Energy Harvesting and Wireless Power Transmission This paper reviews numerous existing efforts and solutions in the field of solar and electromagnetic energy of solar/electromagnetic energy harvest- ing and wireless power transmission. More specifically, the paper
Energy scavenging from low frequency vibrations
NASA Astrophysics Data System (ADS)
Galchev, Tzeno V.
The development of three energy conversion devices that are able to transform vibrations in their surroundings to electrical energy is discussed in this thesis. These energy harvesters are based upon a newly invented architecture called the Parametric Frequency Increased Generator (PFIG). The PFIG structure is designed to efficiently convert low frequency and non-periodic vibrations into electrical power. The three PFIG devices have a combined operating range covering two orders of magnitude in acceleration (0.54--19.6m/s 2) and a frequency range spanning up to 60Hz; making them some of the most versatile generators in existence. The PFIG utilizes a bi-stable mechanical structure to initiate high-frequency mechanical oscillations in an electromechanical scavenger. By up-converting the ambient vibration frequency to a higher internal operation frequency, the PFIG achieves better electromechanical coupling. The fixed internal displacement and dynamics of the PFIG allow it to operate more efficiently than resonant generators when the ambient vibration amplitude is higher than the internal displacement limit of the device. The PFIG structure is capable of efficiently converting mechanical vibrations with variable characteristics including amplitude and frequency, into electrical power. The first electromagnetic harvester can generate a peak power of 163microW and an average power of 13.6microW from an input acceleration of 9.8m/s 2 at 10Hz, and it can operate up to 60Hz. The internal volume of the generator is 2.12cm3 (3.75 including casing). It sets the state-of-the-art in efficiency in the <20Hz range. The volume figure of merit is 0.068%, which is a 10x improvement over other published works. It has a record high bandwidth figure of merit (0.375%). A second piezoelectric implementation generates 3.25microW of average power under the same excitation conditions, while the volume of the generator is halved (1.2cm3). A third PFIG was developed for critical infrastructure monitoring applications. It is used to harvest the very low-amplitude, low-frequency, and non-periodic vibrations present on bridges. The device generates 2.3microW of average power from an input acceleration of 0.54m/s2 at only 2Hz. The internal volume of the generator is 43cm3. It can operate over an unprecedentedly large acceleration (0.54--9.8m/s2) and frequency range (up to 30Hz) without any modifications or tuning.
Wide-bandwidth piezoelectric energy harvester with polymeric structure
NASA Astrophysics Data System (ADS)
Rezaeisaray, Mehdi; El Gowini, Mohamed; Sameoto, Dan; Raboud, Don; Moussa, Walied
2015-01-01
A polymer based energy harvester with wide bandwidth is designed, fabricated and tested in this work. A polymer based structure has a lower resonance frequency compared to a silicon based structure with the same dimensions due to the much lower stiffness of polymeric materials. Therefore, a polymeric energy harvester is more useful for situations with lower ambient vibration frequencies. Aluminum nitride pads are fabricated on an SU-8 membrane to convert mechanical vibration of the membrane to electrical voltage. A new and scalable microfabrication process flow is proposed to properly fabricate piezoelectric layers on SU-8 structures. The nonlinear stiffness due to the stretching strain in the membrane provides a wider harvestable frequency bandwidth than conventional linear oscillators. Wideband energy harvesters are more useful for practical applications due to uncontrollable ambient vibration frequency. The load-deflection equation of the device is calculated using finite element simulation. This equation is then used in an analytical solution to estimate the nonlinear effect of the structure. A bandwidth of ~146?Hz is obtained for the fabricated device and a maximum open circuit voltage of 1.42?V, maximum power of 1.37?µW, and power density of 3.81?µW?cm-2 were measured at terminal load of 357.4?k? under an excitation acceleration of 4?g. A power output of 10.1?µW and power density of 28.1?µW?cm-2 was estimated using a synchronized switch harvesting on interface (SSHI) electrical interface with electrical quality factor of 5. In addition, the lumped element model has been employed to investigate the scaling effect on a polymeric circular diaphragm.
3D, wideband vibro-impacting-based piezoelectric energy harvester
NASA Astrophysics Data System (ADS)
Yu, Qiangmo; Yang, Jin; Yue, Xihai; Yang, Aichao; Zhao, Jiangxin; Zhao, Nian; Wen, Yumei; Li, Ping
2015-04-01
An impacting-based piezoelectric energy harvester was developed to address the limitations of the existing approaches in single-dimensional operation as well as a narrow working bandwidth. In the harvester, a spiral cylindrical spring rather than the conventional thin cantilever beam was utilized to extract the external vibration with arbitrary directions, which has the capability to impact the surrounding piezoelectric beams to generate electricity. And the introduced vibro-impacting between the spiral cylindrical spring and multi-piezoelectric-beams resulted in not only a three-dimensional response to external vibration, but also a bandwidth-broadening behavior. The experimental results showed that each piezoelectric beam exhibited a maximum bandwidth of 8 Hz and power of 41 ?W with acceleration of 1 g (with g=9.8 ms-2) along the z-axis, and corresponding average values of 5 Hz and 45 ?W with acceleration of 0.6 g in the x-y plane.
Energy Harvesting Communications with Hybrid Energy Storage and Processing Cost
Ulukus, Sennur
Energy Harvesting Communications with Hybrid Energy Storage and Processing Cost Omur Ozel Khurram with an energy harvesting transmitter with non-negligible processing circuitry power and a hybrid energy storage for energy storage while the battery has unlimited space. The transmitter stores the harvested energy either
Piezoelectric Energy Harvesting Using PZT Bimorphs and Multilayered Stacks
NASA Astrophysics Data System (ADS)
Panda, Prasanta Kumar; Sahoo, Benudhar; Chandraiah, M.; Raghavan, Sreekumari; Manoj, Bindu; Ramakrishna, J.; Kiran, P.
2015-11-01
Piezoelectric materials have a unique ability to interchange electrical and mechanical energy. This property allows the absorption of mechanical energy such as ambient vibration and its transformation into electrical energy. The electrical energy generated can be used to power low-power electronic devices. In the present study, energy harvesting by lead zirconate titanate (PZT) multilayer (ML) stacks and bimorphs is presented. The devices were fabricated by a tape casting technique and were poled at 2 kV/mm for 30 min immersed in a silicone oil bath maintained at 60°C. The energy harvesting characteristics of the fabricated devices were measured in a suitably assembled test setup. The output voltage obtained from the PZT bimorphs and ML stacks was 450 mV and 125 mV, respectively. The higher output voltage from the bimorph is due to its low capacitance.
Harvesting traffic-induced vibrations for structural health monitoring of bridges
NASA Astrophysics Data System (ADS)
Galchev, T. V.; McCullagh, J.; Peterson, R. L.; Najafi, K.
2011-10-01
This paper discusses the development and testing of a renewable energy source for powering wireless sensors used to monitor the structural health of bridges. Traditional power cables or battery replacement are excessively expensive or infeasible in this type of application. An inertial power generator has been developed that can harvest traffic-induced bridge vibrations. Vibrations on bridges have very low acceleration (0.1-0.5 m s-2), low frequency (2-30 Hz), and they are non-periodic. A novel parametric frequency-increased generator (PFIG) is developed to address these challenges. The fabricated device can generate a peak power of 57 µW and an average power of 2.3 µW from an input acceleration of 0.54 m s-2 at only 2 Hz. The generator is capable of operating over an unprecedentedly large acceleration (0.54-9.8 m s-2) and frequency range (up to 30 Hz) without any modifications or tuning. Its performance was tested along the length of a suspension bridge and it generated 0.5-0.75 µW of average power without manipulation during installation or tuning at each bridge location. A preliminary power conversion system has also been developed.
Energy Harvesting by a Flapping Flag
Psaltis, Demetri
Energy Harvesting by a Flapping Flag Author : Johann Moulin Supervisors : Sébastien Michelin (Lad cycle oscillationsB This is the soEcalled flutter instabilityB If it can be highly destructiveL we can also hope for harvesting E part of E the energy provided to the plate by the fluidB Different
The Energy Harvesting Multiple Access Channel with Energy Storage Losses
Yener, Aylin
The Energy Harvesting Multiple Access Channel with Energy Storage Losses Kaya Tutuncuoglu and Aylin considers a Gaussian multiple access channel with two energy harvesting transmitters with lossy energy storage. The power allocation policy maximizing the average weighted sum rate given the energy harvesting
Experimental analysis of energy harvesting from self-induced flutter of a composite beam
NASA Astrophysics Data System (ADS)
Zakaria, Mohamed Y.; Al-Haik, Mohammad Y.; Hajj, Muhammad R.
2015-07-01
Previous attempts to harvest energy from aeroelastic vibrations have been based on attaching a beam to a moving wing or structure. Here, we exploit self-excited oscillations of a fluttering composite beam to harvest energy using piezoelectric transduction. Details of the beam properties and experimental setup are presented. The effects of preset angle of attack, wind speed, and load resistance on the levels of harvested power are determined. The results point to a complex relation between the aerodynamic loading and its impact on the static deflection and amplitudes of the limit cycle oscillations on one hand and the load resistance and level of power harvested on the other hand.
Structural modelling of a compliant flexure flow energy harvester
NASA Astrophysics Data System (ADS)
Chatterjee, Punnag; Bryant, Matthew
2015-09-01
This paper presents the concept of a flow-induced vibration energy harvester based on a one-piece compliant flexure structure. This energy harvester utilizes the aeroelastic flutter phenomenon to convert flow energy to structural vibrational energy and to electrical power output through piezoelectric transducers. This flexure creates a discontinuity in the structural stiffness and geometry that can be used to tailor the mode shapes and natural frequencies of the device to the desired operating flow regime while eliminating the need for discrete hinges that are subject to fouling and friction. An approximate representation of the flexure rigidity is developed from the flexure link geometry, and a model of the complete discontinuous structure and integrated flexure is formulated based on the transfer matrix method. The natural frequencies and mode shapes predicted by the model are validated using finite element simulations and are shown to be in close agreement. A proof-of-concept energy harvester incorporating the proposed flexure design has been fabricated and investigated in wind tunnel testing. The aeroelastic modal convergence, critical flutter wind speed, power output and limit cycle behavior of this device is experimentally determined and discussed.
Delay-Tolerant Data Gathering in Energy Harvesting Sensor Networks With a Mobile Sink
Liang, Weifa
. The experimental results demonstrate that the proposed algorithms are efficient. To the best of our knowledge to harvest ambient energy such as solar energy, wind energy, vibration energy, and so on, from their sur consist of a fixed sink and hundreds of sensors powered by batteries. The sensing data generated
Automated Checkpointing for Enabling Intensive Applications on Energy Harvesting Devices
supplied. Significant recent progress has been made in creation and development of energy harvesting technologies [10]. However, energy harvesting typically provides (more than two) orders of magnitude less
Applications of energy harvesting for ultralow power technology
NASA Astrophysics Data System (ADS)
Pop-Vadean, A.; Pop, P. P.; Barz, C.; Chiver, O.
2015-06-01
Ultra-low-power (ULP) technology is enabling a wide range of new applications that harvest ambient energy in very small amounts and need little or no maintenance - self-sustaining devices that are capable of perpetual or nearly perpetual operation. These new systems, which are now appearing in industrial and consumer electronics, also promise great changes in medicine and health. Until recently, the idea of micro-scale energy harvesting, and collecting miniscule amounts of ambient energy to power electronic systems, was still limited to research proposals and laboratory experiments.Today an increasing number of systems are appearing that take advantage of light, vibrations and other forms of previously wasted environmental energy for applications where providing line power or maintaining batteries is inconvenient. In the industrial world, where sensors gather information from remote equipment and hazardous processes; in consumer electronics, where mobility and convenience are served; and in medical systems, with unique requirements for prosthetics and non-invasive monitoring, energy harvesting is rapidly expanding into new applications.This paper serves as a survey for applications of energy harvesting for ultra low power technology based on various technical papers available in the public domain.
Parametric design study of an aeroelastic flutter energy harvester
NASA Astrophysics Data System (ADS)
Bryant, Matthew; Wolff, Eric; Garcia, Ephrahim
2011-03-01
This paper investigates a novel mechanism for powering wireless sensors or low power electronics by extracting energy from an ambient fluid flow using a piezoelectric energy harvester driven by aeroelastic flutter vibrations. The energy harvester makes use of a modal convergence flutter instability to generate limit cycle bending oscillations of a cantilevered piezoelectric beam with a small flap connected to its free end by a revolute joint. The critical flow speed at which destabilizing aerodynamic effects cause self-excited vibrations of the structure to emerge is essential to the design of the energy harvester. This value sets the lower bound on the operating wind speed and frequency range of the system. A system of coupled equations that describe the structural, aerodynamic, and electromechanical aspects of the system are used to model the system dynamics. The model uses unsteady aerodynamic modeling to predict the aerodynamic forces and moments acting on the structure and to account for the effects of vortices shed by the flapping wing, while a modal summation technique is used to model the flexible piezoelectric structure. This model is applied to examine the effects on the cut-in wind speed of the system when several design parameters are tuned and the size and mass of the system is held fixed. The effects on the aeroelastic system dynamics and relative sensitivity of the flutter stability boundary are presented and discussed. Experimental wind tunnel results are included to validate the model predictions.
Novel composite piezoelectric material for energy harvesting applications
NASA Astrophysics Data System (ADS)
Janusas, Giedrius; Guobiene, Asta; Palevicius, Arvydas; Prosycevas, Igoris; Ponelyte, Sigita; Baltrusaitis, Valentinas; Sakalys, Rokas
2015-04-01
Past few decades were concentrated on researches related to effective energy harvesting applied in modern technologies, MEMS or MOEMS systems. There are many methods for harvesting energy as, for example, usage of electromagnetic devices, but most dramatic changes were noticed in the usage of piezoelectric materials in small scale devices. Major limitation faced was too small generated power by piezoelectric materials or high resonant frequencies of such smallscale harvesters. In this research, novel composite piezoelectric material was created by mixing PZT powder with 20% solution of polyvinyl butyral in benzyl alcohol. Obtained paste was screen printed on copper foil using 325 mesh stainless steel screen and dried for 30 min at 100 °C. Polyvinyl butyral ensures good adhesion and flexibility of a new material at the conditions that requires strong binding. Five types of a composite piezoelectric material with different concentrations of PZT (40%, 50%, 60%, 70% and 80 %) were produced. As the results showed, these harvesters were able to transform mechanical strain energy into electric potential and, v.v. In experimental setup, electromagnetic shaker was used to excite energy harvester that is fixed in the custom-built clamp, while generated electric potential were registered with USB oscilloscope PICO 3424. The designed devices generate up to 80 ?V at 50 Hz excitation. This property can be applied to power microsystem devices or to use them in portable electronics and wireless sensors. However, the main advantage of the created composite piezoelectric material is possibility to apply it on any uniform or nonuniform vibrating surface and to transform low frequency vibrations into electricity.
Hybrid piezoelectric energy harvesting transducer system
NASA Technical Reports Server (NTRS)
Xu, Tian-Bing (Inventor); Jiang, Xiaoning (Inventor); Su, Ji (Inventor); Rehrig, Paul W. (Inventor); Hackenberger, Wesley S. (Inventor)
2008-01-01
A hybrid piezoelectric energy harvesting transducer system includes: (a) first and second symmetric, pre-curved piezoelectric elements mounted separately on a frame so that their concave major surfaces are positioned opposite to each other; and (b) a linear piezoelectric element mounted separately on the frame and positioned between the pre-curved piezoelectric elements. The pre-curved piezoelectric elements and the linear piezoelectric element are spaced from one another and communicate with energy harvesting circuitry having contact points on the frame. The hybrid piezoelectric energy harvesting transducer system has a higher electromechanical energy conversion efficiency than any known piezoelectric transducer.
Nonlinear time-varying potential bistable energy harvesting from human motion
NASA Astrophysics Data System (ADS)
Cao, Junyi; Wang, Wei; Zhou, Shengxi; Inman, Daniel J.; Lin, Jing
2015-10-01
A theoretical and experimental investigation into nonlinear bistable energy harvesting with time-varying potential energy is presented. The motivation for examining time-varying potentials comes from the desire to harvest energy from human motion. Time-varying potential energy function of bistable oscillator with respect to the swing angle are established to derive the governing electromechanical model for harvesting vibration energy from the swaying motion during human walking or running. Numerical simulations show good agreement with the experimental potential energy function under different swing angles. Various motion speed treadmill tests are performed to demonstrate the advantage of time-varying bistable harvesters over linear and monostable ones in harvesting energy from human motion.
Rossi, Michele
7/30/2014 Smart sensors that harvest power from sun, heat or vibrations https://ec.europa.eu/programmes/horizon2020/en/print/688 1/2 Date: 18/02/2014 - 19:37 Published on Horizon 2020 (https://ec.europa and thermal energy as #12;7/30/2014 Smart sensors that harvest power from sun, heat or vibrations https://ec.europa
Characterization of a rotary hybrid multimodal energy harvester
NASA Astrophysics Data System (ADS)
Larkin, Miles R.; Tadesse, Yonas
2014-04-01
In this study, experimental characterizations of a new hybrid energy harvesting device consisting of piezoelectric and electromagnetic transducers are presented. The generator, to be worn on the legs or arms of a person, harnesses linear motion and impact forces from human motion to generate electrical energy. The device consists of an unbalanced rotor made of three piezoelectric beams which have permanent magnets attached to the ends. Impact forces cause the beams to vibrate, generating a voltage across their electrodes and linear motion causes the rotor to spin. As the rotor spins, the magnets pass over ten electromagnetic coils mounted to the base, inducing a current through the wire. Several design related issues were investigated experimentally in order to optimize the hybrid device for maximum power generation. Further experiments were conducted on the system to characterize the energy harvesting capabilities of the device, all of which are presented in this study.
Soft Capacitors for Wave Energy Harvesting
Karsten Ahnert; Markus Abel; Matthias Kollosche; Per Jørgen Jørgensen; Guggi Kofod
2011-10-14
Wave energy harvesting could be a substantial renewable energy source without impact on the global climate and ecology, yet practical attempts have struggle d with problems of wear and catastrophic failure. An innovative technology for ocean wave energy harvesting was recently proposed, based on the use of soft capacitors. This study presents a realistic theoretical and numerical model for the quantitative characterization of this harvesting method. Parameter regio ns with optimal behavior are found, and novel material descriptors are determined which simplify analysis dramatically. The characteristics of currently ava ilable material are evaluated, and found to merit a very conservative estimate of 10 years for raw material cost recovery.
Bluff Body Fluid Interactions Modelling for Micro Energy Harvesting Application
NASA Astrophysics Data System (ADS)
Bhuyan, M. S.; Majlis, B. Y.; Othman, M.; Ali, Sawal H. Md; Kalaivani, C.; Islam, S.
2013-04-01
In this paper, we have presented a MEMS-based piezoelectric fluid-flow based micro energy harvester. The design and modelling of the energy harvester structure was based on a piezoelectric cantilever affixed to a bluff-body. In a cross fluid flow, pressure in the flow channel, in the wake of the bluff body, fluctuates with the same frequency as the pressure variation caused by the Kármán Vortex Street. This fluctuation of pressure in the flow channel causes the piezoelectric cantilever, trailing the bluff-body, to vibrate in a direction normal to the fluid flow direction. COMSOL finite element analysis software are used for the evaluation of various mechanical analysis of the micro energy harvester structure like, physical the Stress and Strain state in the cantilever structures, Eigen frequency Analysis, Transient analysis to demonstrate the feasibility of the design. Detailed steps of modelling and simulation results of the uniform cantilever were explained. The results confirm the probability of the fluid flow based MEMS energy harvester.
Harvesting energy via fluttering piezoelectric beams in viscous flow
NASA Astrophysics Data System (ADS)
Akcabay, Deniz; Young, Yin
2011-11-01
This work explores the idea of harvesting energy from ambient flows using flexible piezoelectric beams. Beams lose their stability and flutter above a critical length or flow speed or below a critical stiffness. During flutter, beams oscillate in increasing amplitude until they enter a self-sustained limit cycle oscillation, which could be exploited to harvest energy. The objectives of this study are to: (i) identify the flutter boundary of a flexible beam in viscous flow; (ii) explore the energy harvesting potential; and (iii) identify critical non-dimensional parameters and parametric relations that govern the response and stability of thin composite beams vibrating in a viscous fluid. Two-dimensional Navier-Stokes equations are solved with a nonlinear beam model coupled with a linear piezoelectric material constitutive model. The harvested energy potential for various solid/fluid combinations is investigated by varying the critical non-dimensional parameters, which are defined in terms of beam length, density, thickness, and stiffness; fluid speed and density; and piezoelectric material properties.
Low power interface IC's for electrostatic energy harvesting applications
NASA Astrophysics Data System (ADS)
Kempitiya, Asantha
The application of wireless distributed micro-sensor systems ranges from equipment diagnostic and control to real time structural and biomedical monitoring. A major obstacle in developing autonomous micro-sensor networks is the need for local electric power supply, since using a battery is often not a viable solution. This void has sparked significant interest in micro-scale power generators based on electrostatic, piezoelectric and electromagnetic energy conversion that can scavenge ambient energy from the environment. In comparison to existing energy harvesting techniques, electrostatic-based power generation is attractive as it can be integrated using mainstream silicon technologies while providing higher power densities through miniaturization. However the power output of reported electrostatic micro-generators to date does not meet the communication and computation requirements of wireless sensor nodes. The objective of this thesis is to investigate novel CMOS-based energy harvesting circuit (EHC) architectures to increase the level of harvested mechanical energy in electrostatic converters. The electronic circuits that facilitate mechanical to electrical energy conversion employing variable capacitors can either have synchronous or asynchronous architectures. The later does not require synchronization of electrical events with mechanical motion, which eliminates difficulties in gate clocking and the power consumption associated with complex control circuitry. However, the implementation of the EHC with the converter can be detrimental to system performance when done without concurrent optimization of both elements, an aspect mainly overlooked in the literature. System level analysis is performed to show that there is an optimum value for either the storage capacitor or cycle number for maximum scavenging of ambient energy. The analysis also shows that maximum power is extracted when the system approaches synchronous operation. However, there is a region of interest where the storage capacitor can be optimized to produce almost 70% of the ideal power taken as the power harvested with synchronous converters when neglecting the power consumption associated with synchronizing control circuitry. Theoretical predictions are confirmed by measurements on an asynchronous EHC implemented with a macro-scale electrostatic converter prototype. Based on the preceding analysis, the design of a novel ultra low power electrostatic integrated energy harvesting circuit is proposed for efficient harvesting of mechanical energy. The fundamental challenges of designing reliable low power sensing circuits for charge constrained electrostatic energy harvesters with capacity to self power its controller and driver stages are addressed. Experimental results are presented for a controller design implemented in AMI 0.7muM high voltage CMOS process using a macro-scale electrostatic converter prototype. The EHC produces 1.126muW for a power investment of 417nW with combined conduction and controller losses of 450nW which is a 20-30% improvement compared to prior art on electrostatic EHCs operating under charge constrain. Inherently dual plate variable capacitors harvest energy only during half of the mechanical cycle with the other half unutilized for energy conversion. To harvest mechanical energy over the complete mechanical vibration cycle, a low power energy harvesting circuit (EHC) that performs charge constrained synchronous energy conversion on a tri-plate variable capacitor for maximizing energy conversion is proposed. The tri-plate macro electrostatic generator with capacitor variation of 405pF to 1.15nF and 405pF to 1.07nF on two complementary adjacent capacitors is fabricated and used in the characterization of the designed EHC. The integrated circuit fabricated in AMI 0.7muM high voltage CMOS process, produces a total output power of 497nW to a 10muF reservoir capacitor from a 98Hz vibration signal. In summary, the thesis lays out the theoretical and experimental foundation for overcoming the main challenges associated with the desi
Thermal Energy Harvesting from Wildlife
NASA Astrophysics Data System (ADS)
Woias, P.; Schule, F.; Bäumke, E.; Mehne, P.; Kroener, M.
2014-11-01
In this paper we present the measurement of temperature differences between the ambient air and the body temperature of a sheep (Heidschnucke) and its applicability for thermoelectric energy harvesting from livestock, demonstrated via the test of a specially tailored TEG system in a real-life experiment. In three measurement campaigns average temperature differences were found between 2.5 K and 3.5 K. Analytical models and FEM simulations were carried out to determine the actual thermal resistance of the sheep's fur from comparisons with the temperature measurements. With these data a thermoelectric (TEG) generator was built in a thermally optimized housing with adapted heats sink. The whole TEG system was mounted to a collar, including a data logger for recording temperature and TEG voltage. First measurements at the neck of a sheep were accomplished, with a calculated maximal average power output of 173 ?W at the TEG. Taking the necessity of a low-voltage step-up converter into account, an electric output power of 54 ?W is available which comes close to the power consumption of a low-power VHF tracking system.
Energy harvesting via ferrofluidic induction
NASA Astrophysics Data System (ADS)
Monroe, J. G.; Vasquez, Erick S.; Aspin, Zachary S.; Fairley, John D.; Walters, Keisha B.; Berg, Matthew J.; Thompson, Scott M.
2015-05-01
A series of experiments were conducted to investigate and characterize the concept of ferrofluidic induction - a process for generating electrical power via cyclic oscillation of ferrofluid (iron-based nanofluid) through a solenoid. Experimental parameters include: number of bias magnets, magnet spacing, solenoid core, fluid pulse frequency and ferrofluid-particle diameter. A peristaltic pump was used to cyclically drive two aqueous ferrofluids, consisting of 7-10 nm iron-oxide particles and commercially-available hydroxyl-coated magnetic beads (~800 nm), respectively. The solutions were pulsated at 3, 6, and 10 Hz through 3.2 mm internal diameter Tygon tubing. A 1000 turn copper-wire solenoid was placed around the tube 45 cm away from the pump. The experimental results indicate that the ferrofluid is capable of inducing a maximum electric potential of approximately +/- 20 ?V across the solenoid during its cyclic passage. As the frequency of the pulsating flow increased, the ferro-nanoparticle diameter increased, or the bias magnet separation decreased, the induced voltage increased. The type of solenoid core material (copper or plastic) did not have a discernible effect on induction. These results demonstrate the feasibility of ferrofluidic induction and provide insight into its dependence on fluid/flow parameters. Such fluidic/magneto-coupling can be exploited for energy harvesting and/or conversion system design for a variety of applications.
Sound insulation and energy harvesting based on acoustic metamaterial plate
NASA Astrophysics Data System (ADS)
Assouar, Badreddine; Oudich, Mourad; Zhou, Xiaoming
2015-03-01
The emergence of artificially designed sub-wavelength acoustic materials, denoted acoustic metamaterials (AMM), has significantly broadened the range of materials responses found in nature. These engineered materials can indeed manipulate sound/vibration in surprising ways, which include vibration/sound insulation, focusing, cloaking, acoustic energy harvesting …. In this work, we report both on the analysis of the airborne sound transmission loss (STL) through a thin metamaterial plate and on the possibility of acoustic energy harvesting. We first provide a theoretical study of the airborne STL and confronted them to the structure-borne dispersion of a metamaterial plate. Second, we propose to investigate the acoustic energy harvesting capability of the plate-type AMM. We have developed semi-analytical and numerical methods to investigate the STL performances of a plate-type AMM with an airborne sound excitation having different incident angles. The AMM is made of silicone rubber stubs squarely arranged in a thin aluminum plate, and the STL is calculated at low-frequency range [100Hz to 3kHz] for an incoming incident sound pressure wave. The obtained analytical and numerical STL present a very good agreement confirming the reliability of developed approaches. A comparison between computed STL and the band structure of the considered AMM shows an excellent agreement and gives a physical understanding of the observed behavior. On another hand, the acoustic energy confinement in AMM with created defects with suitable geometry was investigated. The first results give a general view for assessing the acoustic energy harvesting performances making use of AMM.
Ultra-wide bandwidth piezoelectric energy harvesting
Hajati, Arman
Here, we present an ultra wide-bandwidth energy harvester by exploiting the nonlinear stiffness of a doubly clamped microelectromechanical systems (MEMSs) resonator. The stretching strain in a doubly clamped beam shows a ...
Vibrational excitation energies from vibrational coupled cluster response theory
NASA Astrophysics Data System (ADS)
Seidler, Peter; Christiansen, Ove
2007-05-01
Response theory in the context of vibrational coupled cluster (VCC) theory is introduced and used to obtain vibrational excitation energies. The relation to the vibrational configuration interaction (VCI) approach is described, and the increase in accuracy of VCC response energies relative to VCI energies is discussed theoretically in terms of a perturbational order expansion and demonstrated numerically. To illustrate the theory, a pilot implementation is used to obtain anharmonic vibrational frequencies for fundamental, first overtone and combination excitations of formaldehyde as well as for the fundamental transitions of ethylene.
NASA Astrophysics Data System (ADS)
Golub, Maksym; Irrgang, Klaus-Dieter; Rusevich, Leonid; Pieper, Jörg
2015-01-01
Vibrational dynamics of the light-harvesting complex II (LHC II) from spinach was investigated by quasi- and inelastic neutron scattering (QENS and INS) at three different temperatures of 80, 160, and 285 K. QENS/INS spectra of solubilised LHC II and of the corresponding buffer solution were obtained separately and exhibit characteristic inelastic features. After subtraction of the buffer contribution, the INS spectrum of LHC II reveals a distinct Boson peak at ˜ 2.5 meV at 80 K that shifts towards lower energies if the temperature is increased to 285 K. This effect is interpreted in terms of a "softening" of the protein matrix along with the dynamical transition at ˜ 240 K. Our findings indicate that INS is a valuable method to obtain the density of vibrational states not only at cryogenic, but also at physiological temperatures.
Optimal design of piezoelectric materials and devices for energy harvesting
NASA Astrophysics Data System (ADS)
Kim, Miso; Dugundji, John; Wardle, Brian L.
2013-06-01
Piezoelectric vibration energy harvesters (PVEHs) have received considerable attention as an enabling technology for self-powered wireless sensor networks. However, the biggest challenge with PVEHs has been their insufficient power generation for practical applications, which necessitates creative and disruptive materials and structure design on various scales. In this work, a model-based design study is performed that includes structural, materials, and device-level power optimizations of PVEHs. The optimization results help in understanding the behavior of the device performance, such as voltage and power, when the devices are optimized under various operating conditions, including input operating frequencies and mechanical damping. Furthermore, the optimization provides both an optimal device design scheme for power improvement and a better understanding of the correlation between the material property and the energy-harvesting output performance.
Helmholtz Resonator for Lead Zirconate Titanate Acoustic Energy Harvester
NASA Astrophysics Data System (ADS)
Matsuda, Tomohiro; Tomii, Kazuki; Hagiwara, Saori; Miyake, Shuntaro; Hasegawa, Yuichi; Sato, Takamitsu; Kaneko, Yuta; Nishioka, Yasushiro
2013-12-01
Acoustic energy harvesters that function in environments where sound pressure is extremely high (~150 dB), such as in engine rooms of aircrafts, are expected to be capable of powering wireless health monitoring systems. This paper presents the power generation performances of a lead-zirconate-titanate (PZT) acoustic energy harvester with a vibrating PZT diaphragm. The diaphragm had a diameter of 2 mm, consisting of Al(0.1 ?m)/PZT(1 ?m)/Pt(0.1 ?m)/Ti(0.1 ?m)/SiO2(1.5 ?m). The harvester generated a power of 1.7×10-13 W under a sound pressure level of 110 dB at the first resonance frequency of 6.28 kHz. It was found that the generated power was increased to 6.8×10-13 W using a sound-collecting Helmholtz resonator cone with the height of 60 mm. The cone provided a Helmholtz resonance at 5.8 kHz, and the generated power increased from 3.4×10-14 W to 1.4×10-13 W at this frequency. The cone was also effective in increasing the bandwidth of the energy harvester.
Multi-directional energy harvesting by piezoelectric cantilever-pendulum with internal resonance
NASA Astrophysics Data System (ADS)
Xu, J.; Tang, J.
2015-11-01
This letter reports a piezoelectric cantilever-pendulum design for multi-directional energy harvesting. A pendulum is attached to the tip of a piezoelectric cantilever-type energy harvester. This design aims at taking advantage of the nonlinear coupling between the pendulum motion in 3-dimensional space and the beam bending vibration at resonances. Experimental studies indicate that, under properly chosen parameters, 1:2 internal resonance can be induced, which enables the multi-directional energy harvesting with a single cantilever. The advantages of the design with respect to traditional piezoelectric cantilever are examined.
Energy harvesting performance of piezoelectric ceramic and polymer nanowires.
Crossley, Sam; Kar-Narayan, Sohini
2015-08-28
Energy harvesting from ubiquitous ambient vibrations is attractive for autonomous small-power applications and thus considerable research is focused on piezoelectric materials as they permit direct inter-conversion of mechanical and electrical energy. Nanogenerators (NGs) based on piezoelectric nanowires are particularly attractive due to their sensitivity to small-scale vibrations and may possess superior mechanical-to-electrical conversion efficiency when compared to bulk or thin-film devices of the same material. However, candidate piezoelectric nanowires have hitherto been predominantly analyzed in terms of NG output (i.e. output voltage, output current and output power density). Surprisingly, the corresponding dynamical properties of the NG, including details of how the nanowires are mechanically driven and its impact on performance, have been largely neglected. Here we investigate all realizable NG driving contexts separately involving inertial displacement, applied stress T and applied strain S, highlighting the effect of driving mechanism and frequency on NG performance in each case. We argue that, in the majority of cases, the intrinsic high resonance frequencies of piezoelectric nanowires (?tens of MHz) present no barrier to high levels of NG performance even at frequencies far below resonance (<1 kHz) typically characteristic of ambient vibrations. In this context, we introduce vibrational energy harvesting (VEH) coefficients ?S and ?T, based on intrinsic materials properties, for comparing piezoelectric NG performance under strain-driven and stress-driven conditions respectively. These figures of merit permit, for the first time, a general comparison of piezoelectric nanowires for NG applications that takes into account the nature of the mechanical excitation. We thus investigate the energy harvesting performance of prototypical piezoelectric ceramic and polymer nanowires. We find that even though ceramic and polymer nanowires have been found, in certain cases, to have similar energy conversion efficiencies, ceramics are more promising in strain-driven NGs while polymers are more promising for stress-driven NGs. Our work offers a viable means of comparing NG materials and devices on a like-for-like basis that may be useful for designing and optimizing nanoscale piezoelectric energy harvesters for specific applications. PMID:26234477
Energy harvesting performance of piezoelectric ceramic and polymer nanowires
NASA Astrophysics Data System (ADS)
Crossley, Sam; Kar-Narayan, Sohini
2015-08-01
Energy harvesting from ubiquitous ambient vibrations is attractive for autonomous small-power applications and thus considerable research is focused on piezoelectric materials as they permit direct inter-conversion of mechanical and electrical energy. Nanogenerators (NGs) based on piezoelectric nanowires are particularly attractive due to their sensitivity to small-scale vibrations and may possess superior mechanical-to-electrical conversion efficiency when compared to bulk or thin-film devices of the same material. However, candidate piezoelectric nanowires have hitherto been predominantly analyzed in terms of NG output (i.e. output voltage, output current and output power density). Surprisingly, the corresponding dynamical properties of the NG, including details of how the nanowires are mechanically driven and its impact on performance, have been largely neglected. Here we investigate all realizable NG driving contexts separately involving inertial displacement, applied stress T and applied strain S, highlighting the effect of driving mechanism and frequency on NG performance in each case. We argue that, in the majority of cases, the intrinsic high resonance frequencies of piezoelectric nanowires (?tens of MHz) present no barrier to high levels of NG performance even at frequencies far below resonance (<1 kHz) typically characteristic of ambient vibrations. In this context, we introduce vibrational energy harvesting (VEH) coefficients ?S and ?T, based on intrinsic materials properties, for comparing piezoelectric NG performance under strain-driven and stress-driven conditions respectively. These figures of merit permit, for the first time, a general comparison of piezoelectric nanowires for NG applications that takes into account the nature of the mechanical excitation. We thus investigate the energy harvesting performance of prototypical piezoelectric ceramic and polymer nanowires. We find that even though ceramic and polymer nanowires have been found, in certain cases, to have similar energy conversion efficiencies, ceramics are more promising in strain-driven NGs while polymers are more promising for stress-driven NGs. Our work offers a viable means of comparing NG materials and devices on a like-for-like basis that may be useful for designing and optimizing nanoscale piezoelectric energy harvesters for specific applications.
An Energy Harvesting AWGN Channel with a Finite Battery
O'Brien, James F.
An Energy Harvesting AWGN Channel with a Finite Battery Varun Jog EECS, UC Berkeley Berkeley, CA to harvest energy per time slot. The harvested energy is either used right away or is stored in a battery of energy harvested per time slot is a constant and the battery has capacity . This imposes a new kind
Optimal Energy Management Policies for Energy Harvesting Sensor Nodes
Sharma, Vinod
1 Optimal Energy Management Policies for Energy Harvesting Sensor Nodes Vinod Sharma, Senior Member with an energy harvesting source. The generated energy can be stored in a buffer. The sensor node periodically the energy available at that time. We obtain energy management policies that are throughput optimal, i
Vibrationally assisted quantum energy pumps
NASA Astrophysics Data System (ADS)
Myers, C. R.; Milburn, G. J.; Twamley, J.
2015-09-01
We show that directed energy transport in a linear array of coupled quantum dots can be achieved by a coherent coupling of each dot to a single coherently driven mechanical mode. Recent work on light harvesting molecules have implicated the role of discrete mechanical modes in enhancing the energy transport through dipole arrays but say less about directed transport. The study of quantum ratchets indicates how directed energy transport is possible in quantum dot arrays. Inspired by these two apparently unrelated models we show how directed energy transport may be implemented in an engineered quantum systems using a single mechanical degree of freedom. This may have implications for nano-engineered artificial energy harvesting systems.
A hydrostatic pressure-cycle energy harvester
NASA Astrophysics Data System (ADS)
Shafer, Michael W.; Hahn, Gregory; Morgan, Eric
2015-04-01
There have been a number of new applications for energy harvesting with the ever-decreasing power consumption of microelectronic devices. In this paper we explore a new area of marine animal energy harvesting for use in powering tags known as bio-loggers. These devices record data about the animal or its surroundings, but have always had limited deployment times due to battery depletion. Reduced solar irradiance below the water's surface provides the impetus to explore other energy harvesting concepts beyond solar power for use on marine animals. We review existing tag technologies in relation to this application, specifically relating to energy consumption. Additionally, we propose a new idea for energy harvesting, using hydrostatic pressure changes as a source for energy production. We present initial testing results of a bench-top model and show that the daily energy harvesting potential from this technology can meet or exceed that consumed by current marine bio-logging tags. The application of this concept in the arena of bio-logging technology could substantially increase bio-logger deployment lifetimes, allowing for longitudinal studies over the course of multiple breeding and/or migration cycles.
NASA Astrophysics Data System (ADS)
Dias, J. A. C.; De Marqui, C.; Erturk, A.
2013-01-01
Piezoelectric and electromagnetic transduction techniques have peculiar advantages to leverage in the growing field of flow energy harvesting from aeroelastic vibrations. This letter presents the concept of hybrid piezoelectric-inductive power generation with electroaeroelastic modeling and simulations. Dimensionless analysis of the coupled system dynamics is indispensable to proper geometric scaling and optimization of aeroelastic energy harvesters. The governing electroaeroelastic equations are given in dimensionless form, and the effects of aeroelastic and electrical properties are investigated in detail toward understanding the dependence of the cut-in speed (flutter speed) and the maximum power output of the harvester on the system parameters.
NASA Astrophysics Data System (ADS)
Zhang, X. F.; Hu, S. D.; Tzou, H. S.
2014-12-01
Converting vibration energy to useful electric energy has attracted much attention in recent years. Based on the electromechanical coupling of piezoelectricity, distributed piezoelectric zero-curvature type (e.g., beams and plates) energy harvesters have been proposed and evaluated. The objective of this study is to develop a generic linear and nonlinear piezoelectric shell energy harvesting theory based on a double-curvature shell. The generic piezoelectric shell energy harvester consists of an elastic double-curvature shell and piezoelectric patches laminated on its surface(s). With a current model in the closed-circuit condition, output voltages and energies across a resistive load are evaluated when the shell is subjected to harmonic excitations. Steady-state voltage and power outputs across the resistive load are calculated at resonance for each shell mode. The piezoelectric shell energy harvesting mechanism can be simplified to shell (e.g., cylindrical, conical, spherical, paraboloidal, etc.) and non-shell (beam, plate, ring, arch, etc.) distributed harvesters using two Lamé parameters and two curvature radii of the selected harvester geometry. To demonstrate the utility and simplification procedures, the generic linear/nonlinear shell energy harvester mechanism is simplified to three specific structures, i.e., a cantilever beam case, a circular ring case and a conical shell case. Results show the versatility of the generic linear/nonlinear shell energy harvesting mechanism and the validity of the simplification procedures.
Optimal Scheduling for Energy Harvesting Transmitters with Hybrid Energy Storage
Ulukus, Sennur
Optimal Scheduling for Energy Harvesting Transmitters with Hybrid Energy Storage Omur Ozel Khurram with an energy harvesting transmitter which has a hybrid energy storage unit composed of a perfectly efficient super-capacitor (SC) and an inefficient battery. The SC has finite space for energy storage while
MEMS electromagnetic energy harvesters with multiple resonances
NASA Astrophysics Data System (ADS)
Nelatury, Sudarshan R.; Gray, Robert
2014-06-01
There is going on a flurry of research activity in the development of effcient energy harvesters from all branches of energy conversion. The need for developing self-powered wireless sensors and actuators to be employed in unmanned combat vehicles also seems to grow steadily. These vehicles are inducted into perilous war zones for silent watch missions. Energy management is sometimes carried out using misson-aware energy expenditure strategies. Also, when there is a requirement for constant monitoring of events, the sensors and the subsystems of combat vehicles require energy harvesters that can operate over a discrete set of spot frequencies. This paper attempts to review some of the recent techniques and the energy harvesting devices based on electromagnetic and electromechanical principles. In particular, we shall discuss the design and performance of a MEMS-harvester that exhibits multiple resonances. Frequency response of a simulated electromagnetic harvester is plotted. It has three dominant peaks at three different resonant frequencies. Variation in the load power in the normalized units as a function of load is found, which determines the matched load resistance.
NASA Astrophysics Data System (ADS)
Dayou, Jedol; Kim, Jaehwan; Im, Jongbeom; Zhai, Lindong; How, Aaron Ting Chuan; Liew, Willey Y. H.
2015-04-01
Previous work shows that when a cantilever piezoelectric energy harvester with a given width is split into several pieces and then electrically connected in parallel, the output power increases substantially compared with when it acts in a single piece with a similar total width. It was hypothesized that this increase is due to the reduction in the damping of the width-reduced beam. As a result, the beam with the smaller width vibrates with higher amplitudes and therefore has higher energy harvesting capability. In this paper, this hypothesis is examined by measuring the damping of the cantilever beam as its width is reduced. It is shown that as the width decreases, the damping is reduced, which contributes to the increase in the harvested power. It is then shown that the harvested energy from an array of cantilever piezobeams with a certain total width is higher than that from a single-piece harvester of similar width.
Energy harvesting of two cantilever beams structure: interfacing circuit discussion
NASA Astrophysics Data System (ADS)
Chen, Yu-Yin; Vasic, Dejan
2015-03-01
Today research on supplying of low power consumption device is highly focused on piezoelectric energy harvesting from ambient vibration. The most popular structure is a cantilever beam with piezoelectric patch to convert mechanical energy into electric energy. In the past researches, the theoretical analysis and interfacing circuit design of single cantilever beam structure is highly developed. In this study, the electrical interfacing circuit of two (or more) piezoelectric generators connected to only one load is proposed and discussed. The nonlinear synchronized switching technique SSHI (Synchronized Switching Harvesting in Inductor) is examined to increase the power efficiency effectively of each piezoelectric generator. In the multiple cantilever beam or flag structure application, the structure may be composed of many piezoelectric patches and the interfacing circuit becomes more complicated and important. From the theoretical analysis and the governing equation, the equivalent circuit of two cantilever beam will be proposed and simulated with the optimized synchronous electric charge extraction (OSECE) nonlinear technique to optimize the interfacing circuit and increase the power efficiency by using the Matlab and PSIM software. The experiments will also show the good agreement with the theoretical analysis. The interfacing circuit design concept in the two cantilever beams structure can be further used in the multi-piezoelectric patches energy harvesting system such as piezoelectric flag to optimize the circuit and increase the power efficiency.
NASA Astrophysics Data System (ADS)
Janphuang, P.; Lockhart, R.; Henein, S.; Briand, D.; de Rooij, N. F.
2013-12-01
This paper demonstrates a novel methodology using a rotational flywheel to determine the energy conversion efficiency of the impact based piezoelectric energy harvesters. The influence of the impact speed and additional proof mass on the efficiency is presented here. In order to convert low frequency mechanical oscillations into usable electrical energy, a piezoelectric harvester is coupled to a rotating gear wheel driven by flywheel. The efficiency is determined from the ratio of the electrical energy generated by the harvester to the mechanical energy dissipated by the flywheel. The experimental results reveal that free vibrations of the harvester after plucking contribute significantly to the efficiency. The efficiency and output energy can be greatly improved by adding a proof mass to the harvester. Under certain conditions, the piezoelectric harvesters have an impact energy conversion efficiency of 1.2%.
Nonlinear analysis of an electrodynamic broadband energy harvester
NASA Astrophysics Data System (ADS)
Bradai, S.; Naifar, S.; Viehweger, C.; Kanoun, O.; Litak, G.
2015-11-01
In order to maximize energy from ambient vibration sources, wide band harvesters working at a range of frequencies are important. This paper presents an electrodynamic energy harvester model working for a frequency band from 25 Hz to 45 Hz. The developed converter consists of a magnetic spring formed by one moving magnet placed between two fixed magnets. A ring magnet is placed around the moving magnet leading to additional nonlinear stiffness to increase the power output. A comparison to a basic configuration electrodynamic converter was carried out by finite element analysis to show that a significant increase in power output was realized. Simulation results have been confirmed by experimental investigations under harmonic excitations. Based on the experimental time series, we have examined the frequency spectrum and phase portraits to identify the dynamic response of the system. In conclusion, the generator is able to harvest 1.5 times more energy than the simple generator for the bandwidth of 20 Hz with the resonant frequency of 35 Hz and the excitation amplitude of 2 mm.
Paper Generators: Harvesting Energy from Touching, Rubbing and Sliding
Poupyrev, Ivan
, PA 15213 USA ABSTRACT We present a new energy harvesting technology that generates electrical energy and Teflon® sheets; they are flexible, light and durable. Our energy harvesting technology can be easily
Finite element modeling of nonlinear piezoelectric energy harvesters with magnetic interaction
NASA Astrophysics Data System (ADS)
Upadrashta, Deepesh; Yang, Yaowen
2015-04-01
Piezoelectric energy harvesting from ambient vibrations is a potential technology for powering wireless sensors and low power electronic devices. The conventional linear harvesters suffer from narrow operational bandwidth. Many attempts have been made especially using the magnetic interaction to broaden the bandwidth of harvesters. The finite element (FE) modeling has been used only for analyzing the linear harvesters in the literature. The main difficulties in extending the FE modeling to analyze the nonlinear harvesters involving magnetic interaction are developing the mesh needed for magnetic interaction in dynamic problems and the high demand on computational resource needed for solving the coupled electrical-mechanical-magnetic problem. In this paper, an innovative method is proposed to model the magnetic interaction without inclusion of the magnetic module. The magnetic force is modeled using the nonlinear spring element available in ANSYS finite element analysis (FEA) package, thus simplifying the simulation of nonlinear piezoelectric energy harvesters as an electromechanically coupled problem. Firstly, an FE model of a monostable nonlinear harvester with cantilever configuration is developed and the results are validated with predictions from the theoretical model. Later, the proposed technique of FE modeling is extended to a complex 2-degree of freedom nonlinear energy harvester for which an accurate analytical model is difficult to derive. The performance predictions from FEA are compared with the experimental results. It is concluded that the proposed modeling technique is able to accurately analyze the behavior of nonlinear harvesters with magnetic interaction.
Piezoelectric cantilever-pendulum for multi-directional energy harvesting with internal resonance
NASA Astrophysics Data System (ADS)
Xu, J.; Tang, J.
2015-04-01
Piezoelectric transducers are widely employed in vibration-based energy harvesting schemes. Simple piezoelectric cantilever for energy harvesting is uni-directional and has bandwidth limitation. In this research we explore utilizing internal resonances to harvest vibratory energy due to excitations from an arbitrary direction with the usage of a single piezoelectric cantilever. Specifically, it is identified that by attaching a pendulum to the piezoelectric cantilever, 1:2 internal resonances can be induced based on the nonlinear coupling. The nonlinear effect induces modal energy exchange between beam bending motion and pendulum motions in 3-dimensional space, which ultimately yield multidirectional energy harvesting by a single cantilever. Systematic analysis and experimental investigation are carried out to demonstrate this new concept.
Electroaeroelastic modeling and analysis of a hybrid piezoelectric-inductive flow energy harvester
NASA Astrophysics Data System (ADS)
Dias, J. A. C.; De Marqui, C.; Erturk, Alper
2013-04-01
The conversion of aeroelastic vibrations into low-power electricity has received growing attention in the energy harvesting literature. Most of the existing research on wind energy harvesting has focused on transforming flow-induced vibrations into electricity by employing electromagnetic or piezoelectric transduction mechanisms separately. In this work, a hybrid airfoil-based aeroelastic energy harvester that simultaneously exploits piezoelectric transduction and electromagnetic induction is analyzed based on fully coupled electroaeroelastic modeling. Both forms of electromechanical coupling are introduced to the plunge degree of freedom. The interaction between total power generation (from piezoelectric transduction and electromagnetic induction) and the linear electroaeroelastic behavior of the typical section is investigated in the presence of two separate electrical loads. The effects of systems parameters, such as internal coil resistance, on the total power output and linear flutter speed are also discussed.
FR4-based electromagnetic energy harvester for wireless sensor nodes
NASA Astrophysics Data System (ADS)
Hatipoglu, G.; Ürey, H.
2010-01-01
Electromagnetic (EM) energy harvesting seems to be one of the most promising ways to power wireless sensors in a wireless sensor network. In this paper, FR4, the most commonly used PCB material, is utilized as a mechanical vibrating structure for EM energy harvesting for body-worn sensors and intelligent tire sensors, which involve impact loadings. FR4 can be a better material for such applications compared to silicon MEMS devices due to lower stiffness and broadband response. In order to demonstrate FR4 performance and broadband response, three moving magnet type EM generator designs are developed and investigated throughout the paper. A velocity-damped harvester simulation model is first developed, including a detailed magnetic model and the magnetic damping effects. The numerical results agree well with the experimental results. Human running acceleration at the hip area that is obtained experimentally is simulated in order to demonstrate system performance, which results in a scavenged power of about 40 µW with 15 m s-2 acceleration input. The designed FR4 energy scavengers with mechanical stoppers implemented are particularly well suited for nearly periodic and non-sinusoidal high- g excitations with rich harmonic content. For the intelligent tire applications, a special compact FR4 scavenger is designed that is able to withstand large shocks and vibrations due to mechanical shock stoppers built into the structure. Using our design, 0.4 mW power across a load resistance at off-resonance operation is obtained in shaker experiments. In the actual operation, the tangential accelerations as a result of the tire-road contact are estimated to supply power around 1 mW with our design, which is sufficient for powering wireless tire sensors. The normalized power density (NPD) of the designed actuators compares favorably with most actuators reported in the literature.
Wideband piezoelectric energy harvester for low-frequency application with plucking mechanism
NASA Astrophysics Data System (ADS)
Hiraki, Yasuhiro; Masuda, Arata; Ikeda, Naoto; Katsumura, Hidenori; Kagata, Hiroshi; Okumura, Hidenori
2015-04-01
Wireless sensor networks need energy harvesting from vibrational environment for their power supply. The conventional resonance type vibration energy harvesters, however, are not always effective for low frequency application. The purpose of this paper is to propose a high efficiency energy harvester for low frequency application by utilizing plucking and SSHI techniques, and to investigate the effects of applying those techniques in terms of the energy harvesting efficiency. First, we derived an approximate formulation of energy harvesting efficiency of the plucking device by theoretical analysis. Next, it was confirmed that the improved efficiency agreed with numerical and experimental results. Also, a parallel SSHI, a switching circuit technique to improve the performance of the harvester was introduced and examined by numerical simulations and experiments. Contrary to the simulated results in which the efficiency was improved from 13.1% to 22.6% by introducing the SSHI circuit, the efficiency obtained in the experiment was only 7.43%. This would due to the internal resistance of the inductors and photo MOS relays on the switching circuit and the simulation including this factor revealed large negative influence of it. This result suggested that the reduction of the switching resistance was significantly important to the implementation of SSHI.
Hu, Yuantai; Xue, Huan; Hu, Ting; Hu, Hongping
2008-01-01
This paper studies the performance of an energy harvester with a piezoelectric bimorph (PB) and a real electrochemical battery (ECB), both are connected as an integrated system through a rectified dc-dc converter (DDC). A vibrating PB can scavenge energy from the operating environment by the electromechanical coupling. A DDC can effectively match the optimal output voltage of the harvesting structure to the battery voltage. To raise the output power density of PB, a synchronized switch harvesting inductor (SSHI) is used in parallel with the harvesting structure to reverse the voltage through charge transfer between the output electrodes at the transition moments from closed-to open-circuit. Voltage reversal results in earlier arrival of rectifier conduction because the output voltage phases of any two adjacent closed-circuit states are just opposite each other. In principle, a PB is with a smaller, flexural stiffness under closed-circuit condition than under open-circuit condition. Thus, the PB subjected to longer closed-circuit condition will be easier to be accelerated. A larger flexural velocity makes the PB to deflect with larger amplitude, which implies that more mechanical energy will be converted into an electric one. Nonlinear interface between the vibrating PB and the modulating circuit is analyzed in detail, and the effects of SSHI and DDC on the charging efficiency of the storage battery are researched numerically. It was found that the introduction of a DDC in the modulating circuit and an SSHI in the harvesting structure can raise the charging efficiency by several times. PMID:18334321
Statistical energy analysis of nonlinear vibrating systems
Spelman, G. M.; Langley, R. S.
2015-01-01
amplitude vibration, without the need for local contacts. Nonlinearity due purely to large amplitude vibration can then result in significant energy being found in frequency bands other than those being driven by external forces. To analyse...
Yuksek, N. S.; Almasri, M.; Feng, Z. C.
2014-09-15
In this paper, we propose an electromagnetic power harvester that uses a transformative multi-impact approach to achieve a wide bandwidth response from low frequency vibration sources through frequency-up conversion. The device consists of a pick-up coil, fixed at the free edge of a cantilever beam with high resonant frequency, and two cantilever beams with low excitation frequencies, each with an impact mass attached at its free edge. One of the two cantilevers is designed to resonate at 25?Hz, while the other resonates at 50?Hz within the range of ambient vibration frequency. When the device is subjected to a low frequency vibration, the two low-frequency cantilevers responded by vibrating at low frequencies, and thus their thick metallic masses made impacts with the high resonance frequency cantilever repeatedly at two locations. This has caused it along with the pick-up coil to oscillate, relative to the permanent magnet, with decaying amplitude at its resonance frequency, and results in a wide bandwidth response from 10 to 63?Hz at 2?g. A wide bandwidth response between 10–51?Hz and 10–58?Hz at acceleration values of 0.5?g and 2?g, respectively, were achieved by adjusting the impact cantilever frequencies closer to each other (25?Hz and 45?Hz). A maximum output power of 85??W was achieved at 5?g at 30?Hz across a load resistor, 2.68 ?.
Magnetic force of piezoelectric cantilever energy harvesters with external magnetic field
NASA Astrophysics Data System (ADS)
Tan, D.; Leng, Y. G.; Gao, Y. J.
2015-11-01
In piezoelectric cantilever energy harvesters with external magnetic field, one of the difficulties is the impact of the external magnetic field or magnetic force on vibration response and energy harvesting efficiency. Here we use the magnetizing current and magnetic dipoles approaches to analyze the magnetic force. The two calculation models are proposed for the energy harvesters. The calculation results of the two methods are compared with a set of experimental data. It has been proved that errors are produced with both methods while the magnet interval is sufficiently small. However, the calculation result achieved from magnetic dipoles approach is closer to experimental measurements than the one of magnetizing current approach. Consequently, the magnetic dipoles approach can be chosen preferably to calculate the magnetic force of piezoelectric cantilever energy harvesters with external magnetic field.
Nonlinear analysis of piezoelectric nanocomposite energy harvesting plates
NASA Astrophysics Data System (ADS)
Rafiee, M.; He, X. Q.; Liew, K. M.
2014-06-01
This paper investigates the nonlinear analysis of energy harvesting from piezoelectric functionally graded carbon nanotube reinforced composite plates under combined thermal and mechanical loadings. The excitation, which derives from harmonically varying mechanical in-plane loading, results in parametric excitation. The governing equations of the piezoelectric functionally graded carbon nanotube reinforced composite plates are derived based on classical plate theory and von Kármán geometric nonlinearity. The material properties of the nanocomposite plate are assumed to be graded in the thickness direction. The single-walled carbon nanotubes (SWCNTs) are assumed to be aligned, straight and have a uniform layout. The linear buckling and vibration behavior of the nanocomposite plates is obtained in the first step. Then, Galerkin’s method is employed to derive the nonlinear governing equations of the problem with cubic nonlinearities associated with mid-plane stretching. Periodic solutions are determined by using the Poincaré-Lindstedt perturbation scheme with movable simply supported boundary conditions. The effects of temperature change, the volume fraction and the distribution pattern of the SWCNTs on the parametric resonance, in particular the amplitude of vibration and the average harvested power of the smart functionally graded carbon nanotube reinforced composite plates, are investigated through a detailed parametric study.
Tilting at MEMS Windmills for Energy Harvesting?
Chiao, Jung-Chih
Tilting at MEMS Windmills for Energy Harvesting? Bill Schweber - February 19, 2015 MEMS and Development (yes, it was print), I saw the story "Micro-Windmills: From Lab to Market" on MEMS devices which, where much of the work is being done in conjunction with support and production from WinMEMS
Vibrational energy transfer in fluids
NASA Astrophysics Data System (ADS)
Miller, David W.; Adelman, Steven A.
A review of several of the available theories of vibrational energy transfer (VET) in the gas and liquid phases is presented. First the classical theory of gas phase VET mainly due to Landau and Teller, to Jackson and Mott and to Zener is developed in some detail. Next the Schwartz-Slawsky-Herzfeld theory, a framework for analysing VET data based on the classical theory, is outlined. Experimental tests of the classical theory and theoretical critiques of its assumptions are then described. Next a brief review of the modern ab-initio quantum approach to gas phase VET rates, taking as an example the work of Banks, Clary and Werner, is given. Theories of VET at elevated densities are then discussed. The isolated binary collision model is reviewed and a new molecular approach to the density, temperature and isotope dependences of vibrational energy relaxation rates, due to Adelman and co-workers, is outlined.
Dielectric elastomer energy harvesting undergoing polarization saturation
NASA Astrophysics Data System (ADS)
Liu, Liwu; Luo, Xiaojian; Liu, Yanju; Leng, Jinsong
2012-04-01
Mechanical energy can be converted into electrical energy by using a dielectric elastomer generator. The elastomer is susceptible to various models of failure, including electrical breakdown, electromechanical instability, loss of tension, and rupture by stretching. The models of failure define a cycle of maximal energy that can be converted. On the other hand, when subjected to voltage, the charge will be induced on a dielectric elastomer. When the voltage is small, the charge increases with the voltage. Along with the continuously increase of voltage, when the charge approaches a certain value, it would become saturated. This paper develops a thermodynamic model of dielectric elastomers undergoing polarization saturation. We studied the typical failure model with three variables of Gent Model silicone energy harvester and obtained an analytical solution of the constitutive equation of dielectric elastomer undergoing polarization saturation. These results can be used to facilitate the design and manufacture of dielectric elastomer energy harvesters.
Multi-resonant wideband energy harvester based on a folded asymmetric M-shaped cantilever
NASA Astrophysics Data System (ADS)
Wu, Meng; Ou, Yi; Mao, Haiyang; Li, Zhigang; Liu, Ruiwen; Ming, Anjie; Ou, Wen
2015-07-01
This article reports a compact wideband piezoelectric vibration energy harvester consisting of three proof masses and an asymmetric M-shaped cantilever. The M-shaped beam comprises a main beam and two folded and dimension varied auxiliary beams interconnected through the proof mass at the end of the main cantilever. Such an arrangement constitutes a three degree-of-freedom vibrating body, which can tune the resonant frequencies of its first three orders close enough to obtain a utility wide bandwidth. The finite element simulation results and the experimental results are well matched. The operation bandwidth comprises three adjacent voltage peaks on account of the frequency interval shortening mechanism. The result shows that the proposed piezoelectric energy harvester could be efficient and adaptive in practical vibration circumstance based on multiple resonant modes.
The fundamental role of quantized vibrations in coherent light harvesting by cryptophyte algae
NASA Astrophysics Data System (ADS)
Kolli, Avinash; O'Reilly, Edward J.; Scholes, Gregory D.; Olaya-Castro, Alexandra
2012-11-01
The influence of fast vibrations on energy transfer and conversion in natural molecular aggregates is an issue of central interest. This article shows the important role of high-energy quantized vibrations and their non-equilibrium dynamics for energy transfer in photosynthetic systems with highly localized excitonic states. We consider the cryptophyte antennae protein phycoerythrin 545 and show that coupling to quantized vibrations, which are quasi-resonant with excitonic transitions is fundamental for biological function as it generates non-cascaded transport with rapid and wider spatial distribution of excitation energy. Our work also indicates that the non-equilibrium dynamics of such vibrations can manifest itself in ultrafast beating of both excitonic populations and coherences at room temperature, with time scales in agreement with those reported in experiments. Moreover, we show that mechanisms supporting coherent excitonic dynamics assist coupling to selected modes that channel energy to preferential sites in the complex. We therefore argue that, in the presence of strong coupling between electronic excitations and quantized vibrations, a concrete and important advantage of quantum coherent dynamics is precisely to tune resonances that promote fast and effective energy distribution.
The fundamental role of quantized vibrations in coherent light harvesting by cryptophyte algae.
Kolli, Avinash; O'Reilly, Edward J; Scholes, Gregory D; Olaya-Castro, Alexandra
2012-11-01
The influence of fast vibrations on energy transfer and conversion in natural molecular aggregates is an issue of central interest. This article shows the important role of high-energy quantized vibrations and their non-equilibrium dynamics for energy transfer in photosynthetic systems with highly localized excitonic states. We consider the cryptophyte antennae protein phycoerythrin 545 and show that coupling to quantized vibrations, which are quasi-resonant with excitonic transitions is fundamental for biological function as it generates non-cascaded transport with rapid and wider spatial distribution of excitation energy. Our work also indicates that the non-equilibrium dynamics of such vibrations can manifest itself in ultrafast beating of both excitonic populations and coherences at room temperature, with time scales in agreement with those reported in experiments. Moreover, we show that mechanisms supporting coherent excitonic dynamics assist coupling to selected modes that channel energy to preferential sites in the complex. We therefore argue that, in the presence of strong coupling between electronic excitations and quantized vibrations, a concrete and important advantage of quantum coherent dynamics is precisely to tune resonances that promote fast and effective energy distribution. PMID:23145719
The fundamental role of quantized vibrations in coherent light harvesting by cryptophyte algae
Avinash Kolli; Edward J. O'Reilly; Gregory D. Scholes; Alexandra Olaya-Castro
2012-10-10
The influence of fast vibrations on energy transfer and conversion in natural molecular aggregates is an issue of central interest. This article shows the important role of high-energy quantized vibrations and their non-equilibrium dynamics for energy transfer in photosynthetic systems with highly localized excitonic states. We consider the cryptophyte antennae protein phycoerythrin 545 and show that coupling to quantized vibrations which are quasi-resonant with excitonic transitions is fundamental for biological function as it generates non-cascaded transport with rapid and wider spatial distribution of excitation energy. Our work also indicates that the non-equilibrium dynamics of such vibrations can manifest itself in ultrafast beating of both excitonic populations and coherences at room temperature, with time scales in agreement with those reported in experiments. Moreover, we show that mechanisms supporting coherent excitonic dynamics assist coupling to selected modes that channel energy to preferential sites in the complex. We therefore argue that, in the presence of strong coupling between electronic excitations and quantized vibrations, a concrete and important advantage of quantum coherent dynamics is precisely to tune resonances that promote fast and effective energy distribution.
Floating Oscillator-Embedded Triboelectric Generator for Versatile Mechanical Energy Harvesting.
Seol, Myeong-Lok; Han, Jin-Woo; Jeon, Seung-Bae; Meyyappan, M; Choi, Yang-Kyu
2015-01-01
A versatile vibration energy harvesting platform based on a triboelectricity is proposed and analyzed. External mechanical vibration repeats an oscillating motion of a polymer-coated metal oscillator floating inside a surrounding tube. Continuous sidewall friction at the contact interface of the oscillator induces current between the inner oscillator electrode and the outer tube electrode to convert mechanical vibrations into electrical energy. The floating oscillator-embedded triboelectric generator (FO-TEG) is applicable for both impulse excitation and sinusoidal vibration which universally exist in usual environment. For the impulse excitation, the generated current sustains and slowly decays by the residual oscillation of the floating oscillator. For the sinusoidal vibration, the output energy can be maximized by resonance oscillation. The operating frequency range can be simply optimized with high degree of freedom to satisfy various application requirements. In addition, the excellent immunity against ambient humidity is experimentally demonstrated, which stems from the inherently packaged structure of FO-TEG. The prototype device provides a peak-to-peak open-circuit voltage of 157?V and instantaneous short-circuit current of 4.6??A, within sub-10?Hz of operating frequency. To visually demonstrate the energy harvesting behavior of FO-TEG, lighting of an array of LEDs is demonstrated using artificial vibration and human running. PMID:26553524
Floating Oscillator-Embedded Triboelectric Generator for Versatile Mechanical Energy Harvesting
NASA Astrophysics Data System (ADS)
Seol, Myeong-Lok; Han, Jin-Woo; Jeon, Seung-Bae; Meyyappan, M.; Choi, Yang-Kyu
2015-11-01
A versatile vibration energy harvesting platform based on a triboelectricity is proposed and analyzed. External mechanical vibration repeats an oscillating motion of a polymer-coated metal oscillator floating inside a surrounding tube. Continuous sidewall friction at the contact interface of the oscillator induces current between the inner oscillator electrode and the outer tube electrode to convert mechanical vibrations into electrical energy. The floating oscillator-embedded triboelectric generator (FO-TEG) is applicable for both impulse excitation and sinusoidal vibration which universally exist in usual environment. For the impulse excitation, the generated current sustains and slowly decays by the residual oscillation of the floating oscillator. For the sinusoidal vibration, the output energy can be maximized by resonance oscillation. The operating frequency range can be simply optimized with high degree of freedom to satisfy various application requirements. In addition, the excellent immunity against ambient humidity is experimentally demonstrated, which stems from the inherently packaged structure of FO-TEG. The prototype device provides a peak-to-peak open-circuit voltage of 157?V and instantaneous short-circuit current of 4.6??A, within sub-10?Hz of operating frequency. To visually demonstrate the energy harvesting behavior of FO-TEG, lighting of an array of LEDs is demonstrated using artificial vibration and human running.
Floating Oscillator-Embedded Triboelectric Generator for Versatile Mechanical Energy Harvesting
Seol, Myeong-Lok; Han, Jin-Woo; Jeon, Seung-Bae; Meyyappan, M.; Choi, Yang-Kyu
2015-01-01
A versatile vibration energy harvesting platform based on a triboelectricity is proposed and analyzed. External mechanical vibration repeats an oscillating motion of a polymer-coated metal oscillator floating inside a surrounding tube. Continuous sidewall friction at the contact interface of the oscillator induces current between the inner oscillator electrode and the outer tube electrode to convert mechanical vibrations into electrical energy. The floating oscillator-embedded triboelectric generator (FO-TEG) is applicable for both impulse excitation and sinusoidal vibration which universally exist in usual environment. For the impulse excitation, the generated current sustains and slowly decays by the residual oscillation of the floating oscillator. For the sinusoidal vibration, the output energy can be maximized by resonance oscillation. The operating frequency range can be simply optimized with high degree of freedom to satisfy various application requirements. In addition, the excellent immunity against ambient humidity is experimentally demonstrated, which stems from the inherently packaged structure of FO-TEG. The prototype device provides a peak-to-peak open-circuit voltage of 157?V and instantaneous short-circuit current of 4.6??A, within sub-10?Hz of operating frequency. To visually demonstrate the energy harvesting behavior of FO-TEG, lighting of an array of LEDs is demonstrated using artificial vibration and human running. PMID:26553524
Energy-harvesting at the Nanoscale
NASA Astrophysics Data System (ADS)
Jordan, Andrew; Sothmann, Björn; Sánchez, Rafael; Büttiker, Markus
2013-03-01
Energy harvesting is the process by which energy is taken from the environment and transformed to provide power for electronics. Specifically, the conversion of thermal energy into electrical power, or thermoelectrics, can play a crucial role in future developments of alternative sources of energy. Unfortunately, present thermoelectrics have low efficiency. Therefore, an important task in condensed matter physics is to find new ways to harvest ambient thermal energy, particularly at the smallest length scales where electronics operate. To achieve this goal, there is on one hand the miniaturizing of electrical devices, and on the other, the maximization of either efficiency or power the devices produce. We will present the theory of nano heat engines able to efficiently convert heat into electrical power. We propose a resonant tunneling quantum dot engine that can be operated either in the Carnot efficient mode, or maximal power mode. The ability to scale the power by putting many such engines in a ``Swiss cheese sandwich'' geometry gives a paradigmatic system for harvesting thermal energy at the nanoscale. This work was supported by the US NSF Grant No. DMR-0844899, the Swiss NSF, the NCCR MaNEP and QSIT, the European STREP project Nanopower, the CSIC and FSE JAE-Doc program, the Spanish MAT2011-24331 and the ITN Grant 234970 (EU)
Technology Transfer Automated Retrieval System (TEKTRAN)
Since the introduction of the first successful mechanical harvester, mechanized cotton harvest has continued to decrease the cost and man hours required to produce a bale of cotton. Cotton harvesting in the US is completely mechanized and is accomplished by two primary machines, the spindle picker a...
Microfabrication and Integration of a Sol-Gel PZT Folded Spring Energy Harvester
Lueke, Jonathan; Badr, Ahmed; Lou, Edmond; Moussa, Walied A.
2015-01-01
This paper presents the methodology and challenges experienced in the microfabrication, packaging, and integration of a fixed-fixed folded spring piezoelectric energy harvester. A variety of challenges were overcome in the fabrication of the energy harvesters, such as the diagnosis and rectification of sol-gel PZT film quality and adhesion issues. A packaging and integration methodology was developed to allow for the characterizing the harvesters under a base vibration. The conditioning circuitry developed allowed for a complete energy harvesting system, consisting a harvester, a voltage doubler, a voltage regulator and a NiMH battery. A feasibility study was undertaken with the designed conditioning circuitry to determine the effect of the input parameters on the overall performance of the circuit. It was found that the maximum efficiency does not correlate to the maximum charging current supplied to the battery. The efficiency and charging current must be balanced to achieve a high output and a reasonable output current. The development of the complete energy harvesting system allows for the direct integration of the energy harvesting technology into existing power management schemes for wireless sensing. PMID:26016911
Microfabrication and integration of a sol-gel PZT folded spring energy harvester.
Lueke, Jonathan; Badr, Ahmed; Lou, Edmond; Moussa, Walied A
2015-01-01
This paper presents the methodology and challenges experienced in the microfabrication, packaging, and integration of a fixed-fixed folded spring piezoelectric energy harvester. A variety of challenges were overcome in the fabrication of the energy harvesters, such as the diagnosis and rectification of sol-gel PZT film quality and adhesion issues. A packaging and integration methodology was developed to allow for the characterizing the harvesters under a base vibration. The conditioning circuitry developed allowed for a complete energy harvesting system, consisting a harvester, a voltage doubler, a voltage regulator and a NiMH battery. A feasibility study was undertaken with the designed conditioning circuitry to determine the effect of the input parameters on the overall performance of the circuit. It was found that the maximum efficiency does not correlate to the maximum charging current supplied to the battery. The efficiency and charging current must be balanced to achieve a high output and a reasonable output current. The development of the complete energy harvesting system allows for the direct integration of the energy harvesting technology into existing power management schemes for wireless sensing. PMID:26016911
Effective energy harvesting devices for railroad applications
NASA Astrophysics Data System (ADS)
Nagode, C.; Ahmadian, M.; Taheri, S.
2010-04-01
The results of the design and development of a new generation of electromagnetic-based energy harvesting systems that can be readily installed in various vehicles are presented. The device resembles a conventional damper or shock absorber that is commonly used for vehicle suspensions. Such devices have received increased attention in the recent years with the much publicized development of GenShock by a group of MIT students. The device described in this study is different than the GenShock technology in that it does not use any fluid, is simpler, and can potentially provide a larger amount of electrical power. The presentation will provide a detailed description of the development of a prototype energy harvester, including the modeling and analysis of the electromagnetic components for increased efficiency. The laboratory test results of the prototype system indicate that more than 20 Watts of RMS energy can be realized at displacements and velocities that resemble the relative motion across a vehicle suspension.
Lead-Zirconate-Titanate Acoustic Energy Harvesters with Dual Top Electrodes
NASA Astrophysics Data System (ADS)
Tomioka, Shungo; Kimura, Shu; Tsujimoto, Kyohei; Iizumi, Satoshi; Uchida, Yusuke; Tomii, Kazuki; Matsuda, Tomohiro; Nishioka, Yasushiro
2011-09-01
In this paper, we present the power generation performances of a lead-zirconate-titanate (PZT) microelectromechanical system (MEMS) acoustic energy harvester having dual top electrodes to utilize the different polarizations of charges on the surface of a vibrating PZT diaphragm at first resonance. The PZT acoustic energy harvester had a diaphragm with a diameter of 2 mm consisting of Al (0.1 µm)/PZT (1 µm)/Pt (0.1 µm)/Ti (0.1 µm)/SiO2 (1.5 µm), and the diaphragm vibrations were excited by sound pressure. The top Al electrodes independently cover the peripheral surface and the central surface of the PZT diaphragm. The peripheral energy harvester generated a power of 5.28×10-11 W, and the central energy harvester generated a power of 4.25×10-11 W at a sound pressure level of 100 dB (0.01 W/m2) at 4.92 kHz. Thus, nearly 80% of the total power of the energy harvesters can be increased by utilizing the polarization at the central part of the diaphragm, which was usually not considered when only the peripheral part of the diaphragm was utilized.
Human Motion Energy Harvesting for AAL Applications
NASA Astrophysics Data System (ADS)
Ylli, K.; Hoffmann, D.; Becker, P.; Willmann, A.; Folkmer, B.; Manoli, Y.
2014-11-01
Research and development into the topic of ambient assisted living has led to an increasing range of devices that facilitate a person's life. The issue of the power supply of these modern mobile systems however has not been solved satisfactorily yet. In this paper a flat inductive multi-coil harvester for integration into the shoe sole is presented. The device is designed for ambient assisted living (AAL) applications and particularly to power a self-lacing shoe. The harvester exploits the horizontal swing motion of the foot to generate energy. Stacks of opposing magnets move through a number of equally spaced coils to induce a voltage. The requirement of a flat structure which can be integrated into the shoe sole is met by a reduced form factor of the magnet stack. In order to exploit the full width of the shoe sole, supporting structures are used to parallelize the harvester and therefore increase the number of active elements, i.e. magnets and coils. The development and characterization of different harvester variations is presented with the best tested design generating an average power of up to 2.14 mW at a compact device size of 75 × 41.5 × 15 mm3 including housing.
Flexible piezoelectric energy harvesting from jaw movements
NASA Astrophysics Data System (ADS)
Delnavaz, Aidin; Voix, Jérémie
2014-10-01
Piezoelectric fiber composites (PFC) represent an interesting subset of smart materials that can function as sensor, actuator and energy converter. Despite their excellent potential for energy harvesting, very few PFC mechanisms have been developed to capture the human body power and convert it into an electric current to power wearable electronic devices. This paper provides a proof of concept for a head-mounted device with a PFC chin strap capable of harvesting energy from jaw movements. An electromechanical model based on the bond graph method is developed to predict the power output of the energy harvesting system. The optimum resistance value of the load and the best stretch ratio in the strap are also determined. A prototype was developed and tested and its performances were compared to the analytical model predictions. The proposed piezoelectric strap mechanism can be added to all types of head-mounted devices to power small-scale electronic devices such as hearing aids, electronic hearing protectors and communication earpieces.
Enhancement of galloping-based wind energy harvesting by synchronized switching interface circuits
NASA Astrophysics Data System (ADS)
Zhao, Liya; Liang, Junrui; Tang, Lihua; Yang, Yaowen; Liu, Haili
2015-04-01
Galloping phenomenon has attracted extensive research attention for small-scale wind energy harvesting. In the reported literature, the dynamics and harvested power of a galloping-based energy harvesting system are usually evaluated with a resistive AC load; these characteristics might shift when a practical harvesting interface circuit is connected for extracting useful DC power. In the family of piezoelectric energy harvesting interface circuits, synchronized switching harvesting on inductor (SSHI) has demonstrated its advantage for enhancing the harvested power from existing base vibrations. This paper investigates the harvesting capability of a galloping-based wind energy harvester using SSHI interfaces, with a focus on comparing the performances of Series SSHI (S-SSHI) and Parallel SSHI (P-SSHI) with that of a standard DC interface, in terms of power at various wind speeds. The prototyped galloping-based piezoelectric energy harvester (GPEH) comprises a piezoelectric cantilever attached with a square-sectioned bluff body made of foam. Equivalent circuit model (ECM) of the GPEH is established and system-level circuit simulations with SSHI and standard interfaces are performed and validated with wind tunnel tests. The benefits of SSHI compared to standard circuit become more significant when the wind speed gets higher; while SSHI circuits lose the benefits at small wind speeds. In both experiment and simulation, the superiority of P-SSHI is confirmed while S-SSHI demands further investigation. The power output is increased by 43.75% with P-SSHI compared to the standard circuit at a wind speed of 6m/s.
An experimentally validated electromagnetic energy harvester
NASA Astrophysics Data System (ADS)
Elvin, Niell G.; Elvin, Alex A.
2011-05-01
A relatively simple method for determining the electromechanical parameters of electromagnetic energy harvesters are presented in this paper. The optimal power generated through a load resistor at both off-resonance and resonance is derived analytically. The experimentally measured performance of a rudimentary electromechanical energy harvester using a rare-earth magnet shows good agreement with the results from the model. The parasitic generator coil resistance can have a profound effect on the overall performance of an electromagnetic generator by essentially acting to degrade the effective coupling coefficient. Data from the setup electromagnetic generator shows normalized power densities of 1.7 ?W/[(m/s 2) 2 cm 3] operating at a resonance frequency of 112.25 Hz. This power density is comparable with other electromagnetic devices of the same volume operating at these frequencies. The power output of the presented electromagnetic generator is comparable to equivalent piezoelectric generators.
Recent Advancements in Nanogenerators for Energy Harvesting.
Hu, Fei; Cai, Qian; Liao, Fan; Shao, Mingwang; Lee, Shuit-Tong
2015-11-01
Nanomaterial-based generators are a highly promising power supply for micro/nanoscale devices, capable of directly harvesting energy from ambient sources without the need for batteries. These generators have been designed within four main types: piezoelectric, triboelectric, thermoelectric, and electret effects, and consist of ZnO-based, silicon-based, ferroelectric-material-based, polymer-based, and graphene-based examples. The representative achievements, current challenges, and future prospects of these nanogenerators are discussed. PMID:26378993
Piezoelectric Materials for Nonlinear Energy Harvesting Generators
NASA Astrophysics Data System (ADS)
Neiss, S.; Goldschmidtboeing, F.; Kroener, M.; Woias, P.
2013-12-01
Nonlinear piezoelectric energy harvesting generators can provide a large bandwidth combined with a good resonant power output. In an experimental study, the influence of the piezoceramic material on these two parameters is investigated. The results prove hard piezoceramics to be better suited as converting element compared to soft piezoceramics. Their improved mechanical quality compensates for their low piezo-mechanical coupling leading to both, a larger bandwidth and a higher power output of the generator.
Development of a biomechanical energy harvester
Li, Qingguo; Naing, Veronica; Donelan, J Maxwell
2009-01-01
Background Biomechanical energy harvesting–generating electricity from people during daily activities–is a promising alternative to batteries for powering increasingly sophisticated portable devices. We recently developed a wearable knee-mounted energy harvesting device that generated electricity during human walking. In this methods-focused paper, we explain the physiological principles that guided our design process and present a detailed description of our device design with an emphasis on new analyses. Methods Effectively harvesting energy from walking requires a small lightweight device that efficiently converts intermittent, bi-directional, low speed and high torque mechanical power to electricity, and selectively engages power generation to assist muscles in performing negative mechanical work. To achieve this, our device used a one-way clutch to transmit only knee extension motions, a spur gear transmission to amplify the angular speed, a brushless DC rotary magnetic generator to convert the mechanical power into electrical power, a control system to determine when to open and close the power generation circuit based on measurements of knee angle, and a customized orthopaedic knee brace to distribute the device reaction torque over a large leg surface area. Results The device selectively engaged power generation towards the end of swing extension, assisting knee flexor muscles by producing substantial flexion torque (6.4 Nm), and efficiently converted the input mechanical power into electricity (54.6%). Consequently, six subjects walking at 1.5 m/s generated 4.8 ± 0.8 W of electrical power with only a 5.0 ± 21 W increase in metabolic cost. Conclusion Biomechanical energy harvesting is capable of generating substantial amounts of electrical power from walking with little additional user effort making future versions of this technology particularly promising for charging portable medical devices. PMID:19549313
NASA Astrophysics Data System (ADS)
Kimura, Shu; Tomioka, Syungo; Iizumi, Satoshi; Tsujimoto, Kyohei; Sugou, Tomohisa; Nishioka, Yasushiro
2011-06-01
Energy harvesters integrable on smart sensor systems have been strongly demanded. Microelectromechanical system (MEMS) acoustic energy harvesters using the first resonance vibration of a lead zirconate titanate (PZT) thin film as a diaphragm have recently been reported. Similar acoustic energy harvesters using the third resonance of a PZT diaphragm fabricated by sol/gel PZT thin film processes exhibited improved generated power density, and it was suggested that the PZT acoustic energy harvester might be suitable for use as a possible power source for silicon integrated circuits. We present further improved power generation performances of PZT MEMS acoustic energy harvesters fabricated by improved PZT capacitor fabrication processes. The PZT acoustic energy harvester with the diaphragm diameter of 1.2 mm fabricated by a sol/gel process generated an even higher energy density of 98 µW/m2 under the sound pressure level of 100 dB (0.01 W/m2) at 16.7 kHz.
Robust segment-type energy harvester and its application to a wireless sensor
NASA Astrophysics Data System (ADS)
Lee, Soobum; Youn, Byeng D.; Jung, Byung C.
2009-09-01
This paper presents an innovative design platform of a piezoelectric energy harvester (EH), called a segment-type EH, and its application to a wireless sensor. Energy harvesting technology is motivated to minimize battery replacement cost for wireless sensors, which aims at developing self-powered sensors by utilizing ambient energy sources. Vibration energy is one of the widely available ambient energy sources which can be converted into electrical energy using piezoelectric material. The current state-of-the-art in piezoelectric EH technology mainly utilizes a single natural frequency, which is less effective when utilizing a random ambient vibration with multi-modal frequencies. This research thus proposes a segment-type harvester to generate electric power efficiently which utilizes multiple modes by separating the piezoelectric material. In order to reflect the random nature of ambient vibration energy, a stochastic design optimization is solved to determine the optimal configuration in terms of energy efficiency and durability. A prototype is manufactured and mounted on a heating, ventilation, air conditioning (HVAC) system to operate a temperature wireless sensor. It shows its excellent performance to generate sufficient power for real-time temperature monitoring for building automation.
Optimized energy harvesting materials and generator design
NASA Astrophysics Data System (ADS)
Graf, Christian; Hitzbleck, Julia; Feller, Torsten; Clauberg, Karin; Wagner, Joachim; Krause, Jens; Maas, Jürgen
2013-04-01
Electroactive polymers are soft capacitors made of thin elastic and electrically insulating films coated with compliant electrodes offering a large amount of deformation. They can either be used as actuators by applying an electric charge or they can be used as energy converters based on the electrostatic principle. These unique properties enable the industrial development of highly efficient and environmentally sustainable energy converters, which opens up the possibility to further exploit large renewable and inexhaustible energy sources like wind and water that are widely unused otherwise. Compared to other electroactive polymer materials, polyurethanes, whose formulations have been systematically modified and optimized for energy harvesting applications, have certain advantages over silicones and acrylates. The inherently higher dipole content results in a significantly increased permittivity and the dielectric breakdown strength is higher, too, whereby the overall specific energy, a measure for the energy gain, is better by at least factor ten, i.e. more than ten times the energy can be gained out of the same amount of material. In order to reduce conduction losses on the electrode during charging and discharging, a highly conductive bidirectional stretchable electrode has been developed. Other important material parameters like stiffness and bulk resistivity have been optimized to fit the requirements. To realize high power energy harvesting systems, substantial amounts of electroactive polymer material are necessary as well as a smart mechanical and electrical design of the generator. In here we report on different measures to evaluate and improve electroactive polymer materials for energy harvesting by e.g. reducing the defect occurrence and improving the electrode behavior.
NASA Astrophysics Data System (ADS)
Amini, Y.; Emdad, H.; Farid, M.
2014-09-01
Piezoelectric energy harvesting (PEH) from ambient energy sources, particularly vibrations, has attracted considerable interest throughout the last decade. Since fluid flow has a high energy density, it is one of the best candidates for PEH. Indeed, a piezoelectric energy harvesting process from the fluid flow takes the form of natural three-way coupling of the turbulent fluid flow, the electromechanical effect of the piezoelectric material and the electrical circuit. There are some experimental and numerical studies about piezoelectric energy harvesting from fluid flow in literatures. Nevertheless, accurate modeling for predicting characteristics of this three-way coupling has not yet been developed. In the present study, accurate modeling for this triple coupling is developed and validated by experimental results. A new code based on this modeling in an openFOAM platform is developed.
Improving Energy Efficiency for Energy Harvesting Embedded Systems*
Qiu, Qinru
Improving Energy Efficiency for Energy Harvesting Embedded Systems* Yang Ge, Yukan Zhang and Qinru efficient energy storage. Hybrid Electrical Energy Storage (HEES) system is proposed recently as a cost improving the energy efficiency and reducing the energy loss during the transfer process. The HEES system
Energy Cooperation in Energy Harvesting Two-Way Communications
Ulukus, Sennur
Energy Cooperation in Energy Harvesting Two-Way Communications Berk Gurakan1 , Omur Ozel1 , Jing energy from nature and energy can be transferred in one-way from one of the users to the other. Energy and users have unlimited batteries to store energy for future use. In addition, there is a separate wireless
Integrated actuation and energy harvesting in prestressed piezoelectric synthetic jets
NASA Astrophysics Data System (ADS)
Mane, Poorna
With the looming energy crisis compounded by the global economic downturn there is an urgent need to increase energy efficiency and to discover new energy sources. An approach to solve this problem is to improve the efficiency of aerodynamic vehicles by using active flow control tools such as synthetic jet actuators. These devices are able to reduce fuel consumption and streamlined vehicle design by reducing drag and weight, and increasing maneuverability. Hence, the main goal of this dissertation is to study factors that affect the efficiency of synthetic jets by incorporating energy harvesting into actuator design using prestressed piezoelectric composites. Four state-of-the-art piezoelectric composites were chosen as active diaphragms in synthetic jet actuators. These composites not only overcome the inherent brittle and fragile nature of piezoelectric materials but also enhance domain movement which in turn enhances intrinsic contributions. With these varying characteristics among different types of composites, the intricacies of the synthetic jet design and its implementation increases. In addition the electrical power requirements of piezoelectric materials make the new SJA system a coupled multiphysics problem involving electro-mechanical and structural-fluid interactions. Due to the nature of this system, a design of experiments approach, a method of combining experiments and statistics, is utilized. Geometric and electro-mechanical factors are investigated using a fractional factorial design with peak synthetic jet velocity as a response variable. Furthermore, energy generated by the system oscillations is harvested with a prestressed composite and a piezo-polymer. Using response surface methodology the process is optimized under different temperatures and pressures to simulate harsh environmental conditions. Results of the fractional factorial experimental design showed that cavity dimensions and type of signal used to drive the synthetic jet actuator were statistically significant factors when studying peak jet velocity. The Bimorph (˜50m/s) and the prestressed metal composite (˜45m/s) generated similar peak jet velocities but the later is the most robust of all tested actuators. In addition, an alternate input signal to the composite, a sawtooth waveform, leads to jets formed with larger peak velocities at frequencies above 15Hz. The optimized factor levels for the energy harvesting process were identified as 237.6kPa, 3.7Hz, 1MO and 12°C and the power density measured at these conditions was 24.27microW/mm3. Finally, the SJA is integrated with an energy harvesting system and the power generated is stored into a large capacitor and a rechargeable battery. After approximately six hours of operation 5V of generated voltage is stored in a 330microF capacitor with the prestressed metal composite as the harvester. It is then demonstrated that energy harvested from the inherent vibrations of a SJA can be stored for later use. Then, the system proposed in this dissertation not only improves on the efficiency of aerodynamic bodies, but also harvests energy that is otherwise wasted.
Tire tread deformation sensor and energy harvester development for smart-tire applications
NASA Astrophysics Data System (ADS)
Moon, Kee S.; Liang, Hong; Yi, Jingang; Mika, Bartek
2007-04-01
Pneumatic tires are critical components in mobile systems that are widely used in our lives for passenger and goods transportation. Wheel/ground interactions in these systems play an extremely important role for not only system design and efficiency but also safe operation. However, fully understanding wheel/ground interactions is challenging because of high complexity of such interactions and the lack of in situ sensors. In this paper, we present the development of a tire tread deformation sensor and energy harvester for real-time tire monitoring and control. Polyvinylidene fluoride (PVDF) based micro-sensor is designed and fabricated to embed inside the tire tread and to measure the tread deformation. We also present a cantilever array based energy harvester that takes advantages of the mechanical bandpass filter concept. The harvester design is able to have a natural frequency band that can be used to harvest energy from varying-frequency vibrational sources. The energy harvester is also built using with new single crystal relaxor ferroelectric material (1 - \\Vkgr)Pb(Mg 1/3Nb 2/3)O 3-\\Vkgr PbTiO 3 (PMN-PT) and interdigited (IDT) electrodes that can perform the energy conversion more efficiently. Some preliminary experiment results show that the performance of the sensor and the energy harvester is promising.
PDMS-based flexible energy harvester with Parylene electret and copper mesh electrodes
NASA Astrophysics Data System (ADS)
Chiu, Y.; Lee, M. H.; Wu, S.-H.
2015-10-01
Currently, most vibrational energy harvesters have rigid and resonant structures to scavenge kinetic energy from periodic motion in specific directions. However, in some situations the motion is random in amplitude, frequency, and direction; or the targeted energy sources apply direct deformation or displacement to the harvesters. In these applications, flexible energy harvesters that are light, flat, and conformable to arbitrary 3D surfaces of the sources are desired to scavenge the energy from device deformation, rather than the motion of a moving mass. Therefore we propose and demonstrate a PDMS-based flexible energy harvester with Parylene-C electret that can be attached to deformable surfaces. Furthermore, copper mesh is embedded in the flexible electrodes for robust electrode metallization as compared with traditional sputtered metal thin films. The fabricated harvesters achieved net output power of 2.2??W, area power density of 2.2??W?cm-2, and volume power density of 22??W?cm-3 at the maximum test frequency of 20?Hz. Power generation by finger tapping and bending was demonstrated. Such harvesters have the potential for wearable and implantable electronic applications.
Park, Steve; Kim, Hyunjin; Vosgueritchian, Michael; Cheon, Sangmo; Kim, Hyeok; Koo, Ja Hoon; Kim, Taeho Roy; Lee, Sanghyo; Schwartz, Gregory; Chang, Hyuk; Bao, Zhenan
2014-11-19
The first stretchable energy-harvesting electronic-skin device capable of differentiating and generating energy from various mechanical stimuli, such as normal pressure, lateral strain, bending, and vibration, is presented. A pressure sensitivity of 0.7 kPa(-1) is achieved in the pressure region <1 kPa with power generation of tens of ?W cm(-2) from a gentle finger touch. PMID:25256696
Self-powered smart blade: helicopter blade energy harvesting
NASA Astrophysics Data System (ADS)
Bryant, Matthew; Fang, Austin; Garcia, Ephrahim
2010-04-01
A novel energy harvesting device powered by aeroelastic flutter vibrations is proposed to generate power for embedded wireless sensors on a helicopter rotor blade. Such wireless sensing and on-board power generation system would eliminate the need for maintenance intensive slip ring systems that are required for hardwired sensors. A model of the system has been developed to predict the response and output of the device as a function of the incident wind speed. A system of coupled equations that describe the structural, aerodynamic, and electromechanical aspects of the system are presented. The model uses semi-empirical, unsteady, nonlinear aerodynamics modeling to predict the aerodynamic forces and moments acting on the structure and to account for the effects of vortex shedding and dynamic stall. These nonlinear effects are included to predict the limit cycle behavior of the system over a range of wind speeds. The model results are compared to preliminary wind tunnel tests of a low speed aeroelastic energy harvesting experiment.
Energy harvesting to power embedded condition monitoring hardware
NASA Astrophysics Data System (ADS)
Farinholt, Kevin; Brown, Nathan; Siegel, Jake; McQuown, Justin; Humphris, Robert
2015-04-01
The shift toward condition-based monitoring is a key area of research for many military, industrial, and commercial customers who want to lower the overall operating costs of capital equipment and general facilities. Assessing the health of rotating systems such as gearboxes, bearings, pumps and other actuation systems often rely on the need for continuous monitoring to capture transient signals that are evidence of events that could cause (i.e. cavitation), or be the result of (i.e. spalling), damage within a system. In some applications this can be accomplished using line powered analyzers, however for wide-spread monitoring, the use of small-scale embedded electronic systems are more desirable. In such cases the method for powering the electronics becomes a significant design factor. This work presents a multi-source energy harvesting approach meant to provide a robust power source for embedded electronics, capturing energy from vibration, thermal and light sources to operate a low-power sensor node. This paper presents the general design philosophy behind the multi-source harvesting circuit, and how it can be extended from powering electronics developed for periodic monitoring to sensing equipment capable of providing continuous condition-based monitoring.
Environmental effects of harvesting forests for energy
Van Hook, R.I.; Johnson, D.W.; West, D.C.; Mann, L.K.
1980-01-01
Present interest in decreasing US dependence on foreign oil by increasing the use of wood for energy may bring about a change in our forest utilization policies. In the past, forests have been removed in areas believed to be suited for agriculture, or sawtimber and pulp have been the only woody material removed in any quantity from land not generally considered tillable. The new demands on wood for energy are effecting a trend toward (1) removing all woody biomass from harvested areas, (2) increasing the frequency of harvesting second growth forests, and (3) increasing production with biomass plantations. Considering the marginal quality of much of the remaining forested land, the impacts of these modes of production could be significant. For example, it is anticipated that increased losses of nutrients and carbon will occur by direct forest removal and through erosion losses accelerated by forest clearing. There are, however, control measures that can be utilized in minimizing both direct and indirect effects of forest harvesting while maximizing woody biomass production.
NASA Astrophysics Data System (ADS)
Buchacz, A.; Bana?, W.; P?aczek, M.
2015-11-01
Piezoelectric transducers are used more and more often in modern technical devices. The wide range of their possible applications is a result of the possibility to use both direct and reverse piezoelectric effect. Nowadays, application of piezoelectric transducers in energy harvesting systems is getting more and more popular. It is caused by the easy way to convert energy of mechanical vibration to the electric voltage using piezoelectric transducers. This paper presents results of influence analysis of the vibrating mechanical subsystem's excitation parameters on the effectiveness of the system designed for energy harvesting. The considered vibrating system is a composite plate with piezoelectric transducer bonded to its surface. Vibrations of the system are excited by means of an actuator with possibility to change the excitation amplitude and frequency. Recovering of electrical energy from mechanical vibrations is possible by using the direct piezoelectric effect - generation of the electric voltage while the transducer is mechanically deformed. In carried out test Macro Fiber Composite (MFC) piezoelectric transducers were used. It was proved that the time that is necessary for switch on the output voltage in analyzed system depends on the frequency of the excitation.
Bistable springs for wideband microelectromechanical energy harvesters
NASA Astrophysics Data System (ADS)
Nguyen, Son D.; Halvorsen, Einar; Paprotny, Igor
2013-01-01
This paper presents experimental results on a microelectromechanical energy harvester with curved springs that demonstrates an extremely wide bandwidth. The springs display an asymmetrical bistable behavior obtained purely through their geometrical design. The frequency down-sweep shows that the harvester 3-dB bandwidth is about 587 Hz at 0.208-g acceleration amplitude. For white noise excitation at 4×10-3 g2/Hz, we found that the bandwidth reaches 715 Hz, which is more than 250 times wider than in the linear-spring regime. By varying the bias voltage, an output power of 3.4 ?W is obtained for frequency down-sweep at 1-g amplitude and 150-V bias.
A low-loss hybrid rectification technique for piezoelectric energy harvesting
NASA Astrophysics Data System (ADS)
Schlichting, A. D.; Fink, E.; Garcia, E.
2013-09-01
Embedded systems have decreased in size and increased in capability; however, small-scale energy storage technologies still significantly limit these advances. Energy neutral operation using small-scale energy harvesting technologies would allow for longer device operation times and smaller energy storage masses. Vibration energy harvesting is an attractive method due to the prevalence of energy sources in many environments. Losses in efficiency due to AC-DC rectification and conditioning circuits limit its application. This work presents a low-loss hybrid rectification technique for piezoelectric vibration energy harvesting using magnetically actuated reed switches and a passive semiconductor full-bridge rectifier. This method shows the capability to have higher efficiency levels and the rectification of low-voltage harvesters without the need for active electrical components. A theoretical model shows that the hybrid rectification technique performance is highly dependent on the proximity delay and the hysteresis behavior of the reed switches. Experimental results validate the model and support the hypothesis of increased performance using the hybrid rectification technique.
Flexible Electret Energy Harvester with Copper Mesh Electrodes
NASA Astrophysics Data System (ADS)
Chiu, Yi; Lee, Ming Hsuan; Hsu, Wei-Hung
2014-11-01
Flexible energy harvesters are desired in biomedical applications since human motion is often complicated and aperiodic. However, most demonstrated flexible energy harvesters employ piezoelectric materials which are not biocompatible. Therefore we propose a PDMS-based flexible energy harvester with Parylene-C electret suitable for biomedical applications. To address the reliability issues of sputtered metal electrodes, we use copper mesh electrodes to improve the reliability. The proposed flexible harvester was fabricated and characterized. The measured power of the proposed harvester was 3.33 pW in the compression tests at 20 Hz and 8.5 nW in the finger bending tests at 2 Hz.
Models for 31-mode PVDF energy harvester for wearable applications.
Zhao, Jingjing; You, Zheng
2014-01-01
Currently, wearable electronics are increasingly widely used, leading to an increasing need of portable power supply. As a clean and renewable power source, piezoelectric energy harvester can transfer mechanical energy into electric energy directly, and the energy harvester based on polyvinylidene difluoride (PVDF) operating in 31-mode is appropriate to harvest energy from human motion. This paper established a series of theoretical models to predict the performance of 31-mode PVDF energy harvester. Among them, the energy storage one can predict the collected energy accurately during the operation of the harvester. Based on theoretical study and experiments investigation, two approaches to improve the energy harvesting performance have been found. Furthermore, experiment results demonstrate the high accuracies of the models, which are better than 95%. PMID:25114981
Models for 31-Mode PVDF Energy Harvester for Wearable Applications
Zhao, Jingjing; You, Zheng
2014-01-01
Currently, wearable electronics are increasingly widely used, leading to an increasing need of portable power supply. As a clean and renewable power source, piezoelectric energy harvester can transfer mechanical energy into electric energy directly, and the energy harvester based on polyvinylidene difluoride (PVDF) operating in 31-mode is appropriate to harvest energy from human motion. This paper established a series of theoretical models to predict the performance of 31-mode PVDF energy harvester. Among them, the energy storage one can predict the collected energy accurately during the operation of the harvester. Based on theoretical study and experiments investigation, two approaches to improve the energy harvesting performance have been found. Furthermore, experiment results demonstrate the high accuracies of the models, which are better than 95%. PMID:25114981
Nonlinear dynamics of a bistable piezoelectric-composite energy harvester for broadband application
NASA Astrophysics Data System (ADS)
Betts, D. N.; Bowen, C. R.; Kim, H. A.; Gathercole, N.; Clarke, C. T.; Inman, D. J.
2013-09-01
The continuing need for reduced power requirements for small electronic components, such as wireless sensor networks, has prompted renewed interest in recent years for energy harvesting technologies capable of capturing energy from ambient vibrations. A particular focus has been placed on piezoelectric materials and devices due to the simplicity of the mechanical to electrical energy conversion and their high strain energy densities compared to electrostatic and electromagnetic equivalents. In this paper an arrangement of piezoelectric layers attached to a bistable asymmetric laminate is investigated experimentally to understand the dynamic response of the structure and power generation characteristics. The inherent bistability of the underlying structure is exploited for energy harvesting since a transition from one stable configuration to another, or "snap-through", is used to repeatedly strain the surface bonded piezoelectric and generate electrical energy. This approach has been shown to exhibit high levels of power extraction over a wide range of vibrational frequencies. Using high speed digital image correlation, a variety of dynamic modes of oscillation are identified in the harvester. The sensitivity of such modes to changes in vibration frequency and amplitude are investigated. Power outputs are measured for repeatable snap-through events of the device and are correlated with the measured modes of oscillation. The typical power generated is approximately 3.2 mW, comparing well with the needs of typical wireless senor node applications.
Energy harvesting of fluttering piezoelectric flags
NASA Astrophysics Data System (ADS)
Doare, Olivier; Michelin, Sebastien; Chen, Jiawan; Xia, Yifan
2012-11-01
The energy harvesting from a flutter instability of a plate equipped with adjacent pairs of piezoelectric elements shunted with independent resistive circuits is considered. When the length of the piezoelectric elements is low compared to the typical wavelengths of bending deformations, governing equations are derived in the form of continuous coupled fluid-solid-electrical equations. These equations are used to perform a linear stability analysis of the coupled system, and a parametric study of the efficiency of the energy transfer from the fluid-solid system to the electrical system addressing both linear and nonlinear dynamics.
Investigation of an energy harvesting small unmanned air vehicle
NASA Astrophysics Data System (ADS)
Magoteaux, Kyle C.; Sanders, Brian; Sodano, Henry A.
2008-03-01
The addition of energy harvesting is investigated to determine the benefits of its integration into a small unmanned air vehicle (UAV). Specifically, solar and piezoelectric energy harvesting techniques were selected and their basic functions analyzed. The initial investigation involved using a fundamental law of thermodynamics, entropy generation, to analyze the small UAV with and without energy harvesting. A notional mission was developed for the comparison that involved the aircraft performing a reconnaissance mission. The analysis showed that the UAV with energy harvesting generated less entropy. However, the UAV without energy harvesting outperformed the other UAV in total flight time at the target. The analysis further looked at future energy harvesting technologies and their effect on the energy harvesting UAV to conduct the mission. The results of the mission using the advanced solar technology showed that the effectiveness of the energy harvesting vehicle would increase. Designs for integrating energy harvesting into the small UAV system were also developed and tests were conducted to show how the energy harvesting designs would perform. It was demonstrated that the addition of the solar and piezoelectric devices would supply usable power for charging batteries and sensors and that it would be advantageous to implement them into a small UAV.
NASA Astrophysics Data System (ADS)
Pozzi, Michele; Zhu, Meiling
2011-05-01
The modern drive towards mobility and wireless devices is motivating intensive research in energy harvesting technologies. To reduce the battery burden on people, we propose the adoption of a frequency up-conversion strategy for a new piezoelectric wearable energy harvester. Frequency up-conversion increases efficiency because the piezoelectric devices are permitted to vibrate at resonance even if the input excitation occurs at much lower frequency. Mechanical plucking-based frequency up-conversion is obtained by deflecting the piezoelectric bimorph via a plectrum, then rapidly releasing it so that it can vibrate unhindered; during the following oscillatory cycles, part of the mechanical energy is converted into electrical energy. In order to guide the design of such a harvester, we have modelled with finite element methods the response and power generation of a piezoelectric bimorph while it is plucked. The model permits the analysis of the effects of the speed of deflection as well as the prediction of the energy produced and its dependence on the electrical load. An experimental rig has been set up to observe the response of the bimorph in the harvester. A PZT-5H bimorph was used for the experiments. Measurements of tip velocity, voltage output and energy dissipated across a resistor are reported. Comparisons of the experimental results with the model predictions are very successful and prove the validity of the model.
NASA Astrophysics Data System (ADS)
El-Etriby, Ahmed E.; Abdel-Meguid, Mohamed E.; Hatem, Tarek M.; Bahei-El-Din, Yehia A.
2014-03-01
Ambient vibrations are major source of wasted energy, exploiting properly such vibration can be converted to valuable energy and harvested to power up devices, i.e. electronic devices. Accordingly, energy harvesting using smart structures with active piezoelectric ceramics has gained wide interest over the past few years as a method for converting such wasted energy. This paper provides numerical and experimental analysis of piezoelectric fiber based composites for energy harvesting applications proposing a multi-scale modeling approach coupled with experimental verification. The multi-scale approach suggested to predict the behavior of piezoelectric fiber-based composites use micromechanical model based on Transformation Field Analysis (TFA) to calculate the overall material properties of electrically active composite structure. Capitalizing on the calculated properties, single-phase analysis of a homogeneous structure is conducted using finite element method. The experimental work approach involves running dynamic tests on piezoelectric fiber-based composites to simulate mechanical vibrations experienced by a subway train floor tiles. Experimental results agree well with the numerical results both for static and dynamic tests.
Wave energy harvesting by piezoelectric flexible plates
NASA Astrophysics Data System (ADS)
Shoele, Kourosh
2013-11-01
The ocean tidal currents and waves are very attractive sources of energy for extraction due to their vast availability and very low environmental impacts. Among different technologies, the harvesting of flow energy through the flapping of flexible plates has recently gained attentions. The sustained oscillation of a flexible plate is the result of a fluid-structure interaction occurrence, mainly from two different situations. In the first case, the oscillation is from the fluttering instability of the plate. In the second case, the unsteady flow is presented in the incoming flow either from the oscillatory sources such as surface waves. The mechanical energy is then converted to electricity using piezoelectric patches connected to the plate. In this paper, we discuss the novel approach to extract the wave energy using piezoelectric plates and discuss how parameters of the piezoelectric plate can be adjusted to increase the amount of energy that can be extracted from the current and free-surface waves.
Performance modeling of unmanned aerial vehicles with on-board energy harvesting
NASA Astrophysics Data System (ADS)
Anton, Steven R.; Inman, Daniel J.
2011-03-01
The concept of energy harvesting in unmanned aerial vehicles (UAVs) has received much attention in recent years. Solar powered flight of small aircraft dates back to the 1970s when the first fully solar flight of an unmanned aircraft took place. Currently, research has begun to investigate harvesting ambient vibration energy during the flight of UAVs. The authors have recently developed multifunctional piezoelectric self-charging structures in which piezoelectric devices are combined with thin-film lithium batteries and a substrate layer in order to simultaneously harvest energy, store energy, and carry structural load. When integrated into mass and volume critical applications, such as unmanned aircraft, multifunctional devices can provide great benefit over conventional harvesting systems. A critical aspect of integrating any energy harvesting system into a UAV, however, is the potential effect that the additional system has on the performance of the aircraft. Added mass and increased drag can significantly degrade the flight performance of an aircraft, therefore, it is important to ensure that the addition of an energy harvesting system does not adversely affect the efficiency of a host aircraft. In this work, a system level approach is taken to examine the effects of adding both solar and piezoelectric vibration harvesting to a UAV test platform. A formulation recently presented in the literature is applied to describe the changes to the flight endurance of a UAV based on the power available from added harvesters and the mass of the harvesters. Details of the derivation of the flight endurance model are reviewed and the formulation is applied to an EasyGlider remote control foam hobbyist airplane, which is selected as the test platform for this study. A theoretical study is performed in which the normalized change in flight endurance is calculated based on the addition of flexible thin-film solar panels to the upper surface of the wings, as well as the addition of flexible piezoelectric patches to the root of the wing spar. Experimental testing is also performed in which the wing spar of the EasyGlider aircraft is modified to include both Macro Fiber Composite and Piezoelectric Fiber Composite piezoelectric patches near the root of the wing and two thin-film solar panels are installed onto the upper wing surface to harvest vibration and solar energy during flight. Testing is performed in which the power output of the various harvesters is measured during flight. Results of the flight testing are used to update the model with accurate measures of the power available from the energy harvesting systems. Finally, the model is used to predict the potential benefits of adding multifunctional self-charging structures to the wing spar of the aircraft in order to harvest vibration energy during flight and provide a local power source for low-power sensors.
Evaluation of the performance of a lead-free piezoelectric material for energy harvesting
NASA Astrophysics Data System (ADS)
Machado, S. P.; Febbo, M.; Rubio-Marcos, F.; Ramajo, L. A.; Castro, M. S.
2015-11-01
Vibration-based energy harvesting has been explored as an auxiliary power source, which can provide small amounts of energy to power remote sensors installed in inaccessible locations. This paper presents an experimental and analytical study of an energy harvesting device using a lead-free piezoelectric material based on {{MoO}}3-doped ({{{K}}}0.44{{Na}}0.52{{Li}}0.04)({{Nb}}0.86{{Ta}}0.10{{Sb}}0.04){{{O}}}3 KNL-(NTS)Mo. The harvesting model corresponds to a cantilever beam with a KNL-(NTS)Mo piezoelectric disc attached to it. We analyze the effect of electromechanical coupling and load resistance on the generated electrical power. Electromechanical frequency response functions that relate the voltage output to the translational base acceleration are shown for experimental and analytical results.
Energy Harvesting Communications with Energy and Data Storage Limitations
Yener, Aylin
Energy Harvesting Communications with Energy and Data Storage Limitations Burak Varan Aylin Yener time minimization problem with finite data and energy storage. The communication set up in [10] does limited energy and data storage. The data transmission policies allow the transmitter to drop some
Potential Ambient Energy-Harvesting Sources and Techniques
ERIC Educational Resources Information Center
Yildiz, Faruk
2009-01-01
Ambient energy harvesting is also known as energy scavenging or power harvesting, and it is the process where energy is obtained from the environment. A variety of techniques are available for energy scavenging, including solar and wind powers, ocean waves, piezoelectricity, thermoelectricity, and physical motions. For example, some systems…
Delay Optimal Scheduling for Energy Harvesting Based Communications
Dai, Huaiyu
ambient environments and rely on this free and regenerative energy supply to transmit packets. Due delay, delay-power tradeoff. I. INTRODUCTION Energy harvesting can provide renewable free energy supply1 Delay Optimal Scheduling for Energy Harvesting Based Communications Juan Liu, Huaiyu Dai, Senior
Energy scavenging from environmental vibration.
Galchev, Tzeno; Apblett, Christopher Alan; Najafi, Khalil
2009-10-01
The goal of this project is to develop an efficient energy scavenger for converting ambient low-frequency vibrations into electrical power. In order to achieve this a novel inertial micro power generator architecture has been developed that utilizes the bi-stable motion of a mechanical mass to convert a broad range of low-frequency (< 30Hz), and large-deflection (>250 {micro}m) ambient vibrations into high-frequency electrical output energy. The generator incorporates a bi-stable mechanical structure to initiate high-frequency mechanical oscillations in an electromagnetic scavenger. This frequency up-conversion technique enhances the electromechanical coupling and increases the generated power. This architecture is called the Parametric Frequency Increased Generator (PFIG). Three generations of the device have been fabricated. It was first demonstrated using a larger bench-top prototype that had a functional volume of 3.7cm3. It generated a peak power of 558{micro}W and an average power of 39.5{micro}W at an input acceleration of 1g applied at 10 Hz. The performance of this device has still not been matched by any other reported work. It yielded the best power density and efficiency for any scavenger operating from low-frequency (<10Hz) vibrations. A second-generation device was then fabricated. It generated a peak power of 288{micro}W and an average power of 5.8{micro}W from an input acceleration of 9.8m/s{sup 2} at 10Hz. The device operates over a frequency range of 20Hz. The internal volume of the generator is 2.1cm{sup 3} (3.7cm{sup 3} including casing), half of a standard AA battery. Lastly, a piezoelectric version of the PFIG is currently being developed. This device clearly demonstrates one of the key features of the PFIG architecture, namely that it is suitable for MEMS integration, more so than resonant generators, by incorporating a brittle bulk piezoelectric ceramic. This is the first micro-scale piezoelectric generator capable of <10Hz operation. The fabricated device currently generates a peak power of 25.9{micro}W and an average power of 1.21{micro}W from an input acceleration of 9.8m/s{sup -} at 10Hz. The device operates over a frequency range of 23Hz. The internal volume of the generator is 1.2cm{sup 3}.
Energy harvesting using a thermoelectric material
Nersessian, Nersesse (Van Nuys, CA); Carman, Gregory P. (Los Angeles, CA); Radousky, Harry B. (San Leandro, CA)
2008-07-08
A novel energy harvesting system and method utilizing a thermoelectric having a material exhibiting a large thermally induced strain (TIS) due to a phase transformation and a material exhibiting a stress induced electric field is introduced. A material that exhibits such a phase transformation exhibits a large increase in the coefficient of thermal expansion over an incremental temperature range (typically several degrees Kelvin). When such a material is arranged in a geometric configuration, such as, for a example, a laminate with a material that exhibits a stress induced electric field (e.g. a piezoelectric material) the thermally induced strain is converted to an electric field.
Electromagnetic energy harvester using coupled oscillating system with 2-degree of freedom
NASA Astrophysics Data System (ADS)
Ung, Chandarin; Moss, Scott D.; Chiu, Wing K.
2015-04-01
This paper presents the design and fabrication of a 2-degree of freedom vibration energy harvesting device for converting kinetic energy into electrical energy using electromagnetic transduction. The relative motion between a magnet and a conductive coil induces an electromotive force. A non-uniform magnetic field design is used where an oscillating magnet is suspended by a spring-damper system. In addition the coil is suspended to serve as the second oscillating mass to effectively harvest energy at two different frequencies. The design parameters are elucidated in this paper which describes the effects of voltage cancellation due to coil phase, coil placement for optimal performance and the benefits of separating magnets using material with high permeability. The investigation was performed using multi physics finite element analysis (COMSOL) with sinusoidal vibration input. A prototype was developed to demonstrate that practical amount of power can be generated from the design. The resonant frequencies of the prototype harvester were tuned to match the dominant frequencies of the host structure (i.e. heavy haul railcars). Peak output powers of 212 mW and 218 mW were generated from sinusoidal vibration with 0.4 g peak acceleration (where g = 9.8 m/s2) at 6.5 Hz and 14.5 Hz respectively.
A mechanical solution of self-powered SSHI interface for piezoelectric energy harvesting systems
NASA Astrophysics Data System (ADS)
Liu, Haili; Ge, Cong; Liang, Junrui
2015-04-01
The synchronized switch interface circuits, e.g., synchronized switch harvesting on inductor (SSHI), can significantly enhance the harvesting capability of piezoelectric energy harvesting (PEH) systems. In these power conditioning circuits, the piezoelectric voltage is flipped with respect to a bias voltage at the instants when the piezoelectric element is at maximum deforming positions. Voltage peak detection and in time switching action are required for implementing these functions. The state-of-the-art solutions are mostly realized by electronic methods, i.e., both functions are carried out by electronic comparators and electronic switches. However, the peak detectors usually introduce switching phase lag; while the electronic switches function only when the vibration magnitude is above a threshold level. When the vibration is lower than such threshold, the SSHI interface shows no improvement. In this paper, we propose a mechanical solution for constructing the self-powered SSHI interface for PEH systems. This technique is realized by installing a low cost vibration sensor switch (VSS) at the free end of a piezoelectric cantilever. It senses the maximum deflecting places of the cantilever and automatically carries out synchronized switching actions. Compared to the existing electronic solutions, this mechanical solution is compact and has relative low switching threshold. Therefore, with this self-powered solution, the advantage of SSHI interface circuit can be sufficiently released, in particular, at low level vibration. Experiment shows the feasibility of this mechanical solution. The advantages and limitations are also discussed in this paper.
Berger, Alaina L.; Palik, Brian; D'Amato, Anthony W.; Fraver, Shawn; Bradford, John B.; Nislow, Keith H.; King, David; Brooks, Robert T.
2013-01-01
Recent interest in using forest residues and small-diameter material for biofuels is generating a renewed focus on harvesting impacts and forest sustainability. The rich legacy of research from whole-tree harvesting studies can be examined in light of this interest. Although this research largely focused on consequences for forest productivity, in particular carbon and nutrient pools, it also has relevance for examining potential consequences for biodiversity and aquatic ecosystems. This review is framed within a context of contrasting ecosystem impacts from whole-tree harvesting because it represents a high level of biomass removal. Although whole-tree harvesting does not fully use the nonmerchantable biomass available, it indicates the likely direction and magnitude of impacts that can occur through energy-wood harvesting compared with less-intensive conventional harvesting and to dynamics associated with various natural disturbances. The intent of this comparison is to gauge the degree of departure of energy-wood harvesting from less intensive conventional harvesting. The review of the literature found a gradient of increasing departure in residual structural conditions that remained in the forest when conventional and whole-tree harvesting was compared with stand-replacing natural disturbance. Important stand- and landscape-level processes were related to these structural conditions. The consequence of this departure may be especially potent because future energy-wood harvests may more completely use a greater range of forest biomass at potentially shortened rotations, creating a great need for research that explores the largely unknown scale of disturbance that may apply to our forest ecosystems.
Mechanics of flexible and stretchable piezoelectrics for energy harvesting
NASA Astrophysics Data System (ADS)
Chen, Ying; Lu, BingWei; Ou, DaPeng; Feng, Xue
2015-09-01
As rapid development in wearable/implantable electronic devices benefit human life in daily health monitoring and disease treatment medically, all kinds of flexible and/or stretchable electronic devices are booming, together with which is the demanding of energy supply with similar mechanical property. Due to its ability in converting mechanical energy lying in human body into electric energy, energy harvesters based on piezoelectric materials are promising for applications in wearable/ implantable device's energy supply in a renewable, clean and life-long way. Here the mechanics of traditional piezoelectrics in energy harvesting is reviewed, including why piezoelectricity is the choice for minor energy harvesting to power the implantable/wearable electronics and how. Different kinds of up to date flexible piezoelectric devices for energy harvesting are introduced, such as nanogenerators based on ZnO and thin and conformal energy harvester based on PZT. A detailed theoretical model of the flexible thin film energy harvester based on PZT nanoribbons is summarized, together with the in vivo demonstration of energy harvesting by integrating it with swine heart. Then the initial researches on stretchable energy harvesters based on piezoelectric material in wavy or serpentine configuration are introduced as well.
Energy Harvesting for Self-Powered Nanosystems Zhong Lin Wang
Wang, Zhong L.
Energy Harvesting for Self-Powered Nanosystems Zhong Lin Wang School of Materials Science In this article, an introduction is presented about the energy harvesting technologies that have potential. This is a potential technology for converting mechanical movement energy (such as body movement, muscle stretching
Transfer matrix modeling of a tensioned piezo-solar hybrid energy harvesting ribbon
NASA Astrophysics Data System (ADS)
Chatterjee, Punnag; Bryant, Matthew
2015-04-01
This paper proposes a multifunctional compliant structure that can harvest electrical power from both incident sunlight and ambient mechanical energy including wind flow or vibration. The energy harvesting device consists of a slender, ribbon-like, flexible thin film solar cell that is laminated with piezoelectric patches. The harvester is mounted in longitudinal tension and subjected to a transverse wind flow to excite flow-induced aeroelastic vibrations. This paper formulates an analytic model of the bending dynamics of the device. We present a Transfer Matrix formulation that also accounts for the changes in natural frequencies and mode shapes of the system when subjected to axial loads in a beam. It also observed that mode shape obtained using TMM formulation shows numerical stability even for very high tensile loads providing results consistent with the geometric boundary conditions applied at the ends of a beam. This article also discusses about structurally modeling a piezo - solar energy harvester using TMM methodology, where a thin clampedclamped solar film is bonded with piezo patches having a much higher bending stiffness. Additionally, the effect of axial tension on the mode shape of the thin host structure of the piezo-solar ribbon is presented and it is shown how this tension can be used advantageously to affect the strain distribution of the entire structure and introduce higher strains at the piezo patches.
Enhanced piezoelectric energy harvesting of a bistable oscillator with an elastic magnifier
NASA Astrophysics Data System (ADS)
Wang, Guang Qing; Liao, Wei-Hsin
2015-04-01
This paper presents theoretical investigation on a coupling system consisting of bistable oscillator with an elastic magnifier (EM) to improve the output performances in vibration energy harvesting. Lumped-parameter nonlinear equations of the coupling system are derived to describe the broadband large-amplitude periodic displacement responses of the coupling system. The effects of the system mass ratio and stiffness ration on the output performances are studied. It shows that increasing the mass ratio and stiffness ratio can improve the system output performances. The distinct advantage in the coupling system lies in the existence of large-orbit periodic vibration over low level range. With the comparison of the electromechanical trajectories obtained from simulations, it shows that the coupling system can harvest more power at low excitation level with larger bandwidth as compared to the bistable oscillator without an EM.
Energy harvesting with piezoelectric applied on shoes
NASA Astrophysics Data System (ADS)
Camilloni, Enrico; Carloni, Mirko; Giammarini, Marco; Conti, Massimo
2013-05-01
In the last few years the continuous demand of energy saving has brought continuous research on low-power devices, energy storage and new sources of energy. Energy harvesting is an interesting solution that captures the energy from the environment that would otherwise be wasted. This work presents an electric-mechanical model of a piezoelectric transducer in a cantilever configuration. The model has been characterized measuring the acceleration and the open circuit voltage of a piezoelectric cantilever subjected to a sinusoidal force with different values frequency and subject to an impulsive force. The model has been used to identify the optimal position in which the piezoelectric cantilever has to be placed on a shoe in order to obtain the maximum energy while walking or running. As a second step we designed the DC-DC converter with an hysteresis comparator. The circuit is able to give energy to switch on a microprocessor for the amount of time long enough to capture and store the information required. The complete system has been implemented, installed on a shoe and used in a 10 Km running competition.
NASA Astrophysics Data System (ADS)
Zhao, Liya; Yang, Yaowen
2015-07-01
Recently, the concept of harvesting available energy from the surrounding environment of electronic devices to implement self-powered stand-alone units has attracted a dramatic increase in interest. Many studies have been conducted on the analytical solutions of output responses for vibration-based piezoelectric energy harvesters (VPEHs), with both simple ac circuit and advanced circuits such as impedance adaptation, synchronized switching harvesting on inductor (SSHI) and synchronized charge extraction (SCE). However, very little effort has been devoted to deriving explicit output responses of aeroelastic piezoelectric energy harvesters, especially for cases involving sophisticated interface circuits. This paper proposes analytical solutions of the responses of a galloping-based piezoelectric energy harvester (GPEH). Three different interfacing circuits, including the simple ac, standard and SCE circuits, are considered in the analysis, with which the explicit expressions of power, voltage and displacement amplitude are derived. The optimal load and coupling are calculated for maximum power generation. The cut-in wind speeds for these circuits are also formulated. Wind tunnel experiments based on a prototype of a GPEH with a square sectioned bluff body and circuit simulation based on the equivalent circuit model are carried out to validate the analysis. Recommendations on the applicability of different circuits are provided based on the observed behaviors of the circuits. The proposed theoretical solutions provide significant guidelines for accurate evaluation of effectiveness of GPEHs and the scheme of normalization makes it convenient to compare devices with various parameters.
The Energy Harvesting and Energy Cooperating Two-way Channel with Finite-Sized Batteries
Yener, Aylin
The Energy Harvesting and Energy Cooperating Two-way Channel with Finite-Sized Batteries Kaya@ee.psu.edu Abstract--In this paper, we consider the energy allocation problem for energy harvesting and energy problem in a two-way channel with energy harvesting nodes that can also transfer energy to one another
Investigation of bistable piezo-composite plates for broadband energy harvesting
NASA Astrophysics Data System (ADS)
Betts, David N.; Bowen, Christopher R.; Kim, H. Alicia; Gathercole, Nicholas; Clarke, Christopher T.; Inman, Daniel J.
2013-04-01
The need to power small electronic components, such as wireless sensor networks, has prompted interest in energy harvesting technologies capable of generating electrical energy from ambient vibrations. There has been a particular focus on piezoelectric materials and devices due to the simplicity of the mechanical to electrical energy conversion and their high strain energy densities compared to electrostatic and electromagnetic equivalents. This paper describes research on an arrangement of piezoelectric elements attached to a bistable asymmetric laminate to understand the dynamic response of the structure and power generation characteristics. The inherent bistability of the underlying structure is exploited for energy harvesting since 'snap-through' from one stable configuration to another is used to strain the piezoelectric materials bonded to the laminate and generate piezoelectric energy. Using high speed digital image correlation, a variety of dynamic modes of oscillation are identified in the bistable harvester. The sensitivity of such vibrational modes to changes in frequency and amplitude are investigated. Electrical power outputs are measured for repeatable snap-through events and are correlated with the modes of oscillation. The typical power generated is approximately 25mW and compares well with the needs of typical wireless senor node applications.
Zinc Oxide Coated Carbon Nanotubes for Energy Harvesting Applications
NASA Astrophysics Data System (ADS)
Mohney, Austin; Stollberg, David
2012-02-01
Small scale electrical devices depend on bulky batteries that require recharging or replacement. In biomedical monitoring, where sensors could be implanted inside the body, maintenance of batteries presents a problem. It would be beneficial if small scale devices could generate their own power and alleviate their dependence on batteries. Piezoelectric nanogenerators have proven themselves as a viable means for ambient energy harvesting. Piezoelectric materials, such as zinc oxide (ZnO), produce a voltage difference when subjected to mechanical strain. Manipulation of this voltage can allow for the storage of energy to power small scale devices. The objective of this research is to manufacture a piezo-generator that can transduce mechanical vibrations into electrical energy. Carbon nanotubes, selected for their strong, flexible, and conductive properties, are used as a structural backbone for a ZnO piezoelectric coating and a Ag electrode coating. A Schottky diode interface is used to rectify the current output of the device. The devices yielded an average current output of .79 microAmps. SEM imagining was used to characterize the fabrication process. A Keithley 2700 digital multimeter was used to characterize the current output of the devices.
NASA Astrophysics Data System (ADS)
Mirab, Hadi; Fathi, Reza; Jahangiri, Vahid; Ettefagh, Mir Mohammad; Hassannejad, Reza
2015-12-01
One of the new methods for powering low-power electronic devices at sea is a wave energy harvesting system. In this method, piezoelectric material is employed to convert the mechanical energy of sea waves into electrical energy. The advantage of this method is based on avoiding a battery charging system. Studies have been done on energy harvesting from sea waves, however, considering energy harvesting with random JONSWAP wave theory, then determining the optimum values of energy harvested is new. This paper does that by implementing the JONSWAP wave model, calculating produced power, and realistically showing that output power is decreased in comparison with the more simple airy wave model. In addition, parameters of the energy harvester system are optimized using a simulated annealing algorithm, yielding increased produced power.
Magnetic Stoppers on Single Beam Piezoelectric Energy Harvesting
NASA Astrophysics Data System (ADS)
Shih, Y. S.; Vasic, D.; Costa, F.; Wu, W. J.
The single beam structure has been long used in piezoelectric energy harvesting to harvest the vibrations of the circumstances. One of the critical defects of the structure is its narrow band of operating frequency. Many propose mechanical stoppers, rigid or non-rigid, such as another beam, to create a non-linear broadband effect. Moreover, with a piecewise linear PEG (Piezoelectric Energy Generator), or a simple cantilever beam with one or two mechanical stoppers laid on its sides, the constant driven amplitude of the beam displacement can be enlarged by a perturbation. It is also proposed that the stoppers prevent the piezoelectric pad from cracking due to over deformation. However, from a long-term point of view, the impact of the beam on the stoppers can also cause faster fatigue of the beam body, not to mention the noise that will hinder its practical application which maybe apparatuses nearby human. Therefore, this paper proposes a magnetic pair to serve as the stoppers for piezoelectric beam, so as to perform similar effects of bandwidth enlargement and also the amplification using perturbation. With no actual contacts, the single beam can be well protected, but also eliminated from over bending by the magnets. By placing the magnets on a beam on each side of the main beam. The magnetic force, which is distance dependent, can provide a smoother feedback to the beam, giving a greater displacement in comparison to the mechanical stopper. Moreover, the characteristic of the beam output is altered so that there exists two peaking frequencies, depending on the design of the stopper beams.
On Kinetics Modeling of Vibrational Energy Transfer
NASA Technical Reports Server (NTRS)
Gilmore, John O.; Sharma, Surendra P.; Cavolowsky, John A. (Technical Monitor)
1996-01-01
Two models of vibrational energy exchange are compared at equilibrium to the elementary vibrational exchange reaction for a binary mixture. The first model, non-linear in the species vibrational energies, was derived by Schwartz, Slawsky, and Herzfeld (SSH) by considering the detailed kinetics of vibrational energy levels. This model recovers the result demanded at equilibrium by the elementary reaction. The second model is more recent, and is gaining use in certain areas of computational fluid dynamics. This model, linear in the species vibrational energies, is shown not to recover the required equilibrium result. Further, this more recent model is inconsistent with its suggested rate constants in that those rate constants were inferred from measurements by using the SSH model to reduce the data. The non-linear versus linear nature of these two models can lead to significant differences in vibrational energy coupling. Use of the contemporary model may lead to significant misconceptions, especially when integrated in computer codes considering multiple energy coupling mechanisms.
Harvesting dissipated energy with a mesoscopic ratchet.
Roche, B; Roulleau, P; Jullien, T; Jompol, Y; Farrer, I; Ritchie, D A; Glattli, D C
2015-01-01
The search for new efficient thermoelectric devices converting waste heat into electrical energy is of major importance. The physics of mesoscopic electronic transport offers the possibility to develop a new generation of nanoengines with high efficiency. Here we describe an all-electrical heat engine harvesting and converting dissipated power into an electrical current. Two capacitively coupled mesoscopic conductors realized in a two-dimensional conductor form the hot source and the cold converter of our device. In the former, controlled Joule heating generated by a voltage-biased quantum point contact results in thermal voltage fluctuations. By capacitive coupling the latter creates electric potential fluctuations in a cold chaotic cavity connected to external leads by two quantum point contacts. For unequal quantum point contact transmissions, a net electrical current is observed proportional to the heat produced. PMID:25828578
Harvesting dissipated energy with a mesoscopic ratchet
NASA Astrophysics Data System (ADS)
Roche, B.; Roulleau, P.; Jullien, T.; Jompol, Y.; Farrer, I.; Ritchie, D. A.; Glattli, D. C.
2015-04-01
The search for new efficient thermoelectric devices converting waste heat into electrical energy is of major importance. The physics of mesoscopic electronic transport offers the possibility to develop a new generation of nanoengines with high efficiency. Here we describe an all-electrical heat engine harvesting and converting dissipated power into an electrical current. Two capacitively coupled mesoscopic conductors realized in a two-dimensional conductor form the hot source and the cold converter of our device. In the former, controlled Joule heating generated by a voltage-biased quantum point contact results in thermal voltage fluctuations. By capacitive coupling the latter creates electric potential fluctuations in a cold chaotic cavity connected to external leads by two quantum point contacts. For unequal quantum point contact transmissions, a net electrical current is observed proportional to the heat produced.
MEMS based pyroelectric thermal energy harvester
Hunter, Scott R; Datskos, Panagiotis G
2013-08-27
A pyroelectric thermal energy harvesting apparatus for generating an electric current includes a cantilevered layered pyroelectric capacitor extending between a first surface and a second surface, where the first surface includes a temperature difference from the second surface. The layered pyroelectric capacitor includes a conductive, bimetal top electrode layer, an intermediate pyroelectric dielectric layer and a conductive bottom electrode layer. In addition, a pair of proof masses is affixed at a distal end of the layered pyroelectric capacitor to face the first surface and the second surface, wherein the proof masses oscillate between the first surface and the second surface such that a pyroelectric current is generated in the pyroelectric capacitor due to temperature cycling when the proof masses alternately contact the first surface and the second surface.
Energy Harvesting Using PVDF Piezoelectric Nanofabric
NASA Astrophysics Data System (ADS)
Shafii, Chakameh Shafii
Energy harvesting using piezoelectric nanomaterial provides an opportunity for advancement towards self-powered electronics. The fabrication complexities and limited power output of these nano/micro generators have hindered these advancements thus far. This thesis presents a fabrication technique with electrospinning using a grounded cylinder as the collector. This method addresses the difficulties with the production and scalability of the nanogenerators. The non-aligned nanofibers are woven into a textile form onto the cylindrical drum that can be easily removed. The electrical poling and mechanical stretching induced by the electric field and the drum rotation increase the concentration of the piezoelectric beta phase in the PVDF nanofabric. The nanofabric is placed between two layers of polyethylene terephthalate (PET) that have interdigitated electrodes painted on them with silver paint. Applying continuous load onto the flexible PVDF nanofabric at 35Hz produces a peak voltage of 320 mV and maximum power of 2200 pW/(cm2) .
NASA Astrophysics Data System (ADS)
M. N. Fakhzan M., K.; Nasrul F. M., N.; Raman, S.; Muthalif, Asan G. A.
2015-05-01
This paper is a preliminary work to explore the feasibility of cubic silicon carbide on silicon wafers with integrated proof mass as horizontal cantilever with vertical displacement. The reason of harvesting ambient vibration energy is to convert mechanical energy produces by piezoelectric into useful electrical energy. The collectable energy is useful for powering the low-power devices. Theoretically, the resonant phenomena are a special characteristic in order to optimize the generated output power. The natural frequency of the cantilever can to be tuned with difference proof masses. Another parameter considered in this paper is the damping ratio. Throughout analytical study, small damping ratio will enhance the output power of the piezoelectric energy harvester (PEH). This paper will present a mathematical modelling approach and the simulation validation.
Techniques for Maximizing Efficiency of Solar Energy Harvesting Systems (Invited Paper)
Shinozuka, Masanobu
Techniques for Maximizing Efficiency of Solar Energy Harvesting Systems (Invited Paper) Pai H requiring battery replacement. This paper ex- amines technical issues with solar energy harvesting. First power point tracking, energy harvest- ing, solar panel, photovoltaic cell, supercapacitor, ultracapac
Energy harvesting with piezoelectric grass for autonomous self-sustaining sensor networks
NASA Astrophysics Data System (ADS)
Hobeck, Jared Dale
The primary objective of this research is to develop a deploy-and-forget energy harvesting device for use in low velocity, highly turbulent, and unpredictable fluid flow environments. The work presented in this dissertation focuses on a novel, lightweight, highly robust, energy harvester design referred to as piezoelectric grass. This biologically inspired design consists of an array of cantilevers, constructed with piezoelectric material. When exposed to a wide range of flow conditions, these cantilevers experience vigorous persistent vibration. Included in this work is an experimentally validated theoretical analysis of the piezoelectric grass harvester generalized for the case of a single cantilever in turbulent cross-flow. A brief parameter optimization study is presented using this distributed parameter model. Two high-sensitivity pressure probes were needed to perform spatiotemporal measurements within various turbulent flows. Measurements with these probes are used to develop a turbulent fluid forcing function. This function is then combined with an analytical structural dynamics model such that not only the modal RMS displacements, but also the modal displacement power spectral density trends are predicted for a given structure. Pressure probe design, turbulence measurement techniques, and both statistical and analytical models are validated with experimental results. An experimental investigation on the energy harvesting potential of large harvester arrays containing up to 112 flexible piezoelectric structures is presented. Experimental results show that a given array will experience large amplitude, waving, resonant-type vibration over a large range of velocities, and is unaffected by large-scale turbulence upstream of the array. These dynamic characteristics make large arrays of flexible piezoelectric structures ideal for many energy harvesting applications. Lastly, this dissertation presents the first documented investigation of a flow-induced vibration phenomenon referred to as dual cantilever flutter (DCF). At a particular combination of flow velocity and distance between two adjacent beams, aeroelastic coupling between the beams causes them to become unstable and undergo limit cycle oscillations. An attractive feature of DCF for energy harvesting is that it provides robust flow-induced excitation over a large range of flow velocities. An experimentally validated lumped parameter model for DCF is presented. Results include CFD simulations that were setup and executed using ANSYS-CFX.
Impedance adaptation methods of the piezoelectric energy harvesting
NASA Astrophysics Data System (ADS)
Kim, Hyeoungwoo
In this study, the important issues of energy recovery were addressed and a comprehensive investigation was performed on harvesting electrical power from an ambient mechanical vibration source. Also discussed are the impedance matching methods used to increase the efficiency of energy transfer from the environment to the application. Initially, the mechanical impedance matching method was investigated to increase mechanical energy transferred to the transducer from the environment. This was done by reducing the mechanical impedance such as damping factor and energy reflection ratio. The vibration source and the transducer were modeled by a two-degree-of-freedom dynamic system with mass, spring constant, and damper. The transmissibility employed to show how much mechanical energy that was transferred in this system was affected by the damping ratio and the stiffness of elastic materials. The mechanical impedance of the system was described by electrical system using analogy between the two systems in order to simply the total mechanical impedance. Secondly, the transduction rate of mechanical energy to electrical energy was improved by using a PZT material which has a high figure of merit and a high electromechanical coupling factor for electrical power generation, and a piezoelectric transducer which has a high transduction rate was designed and fabricated. The high g material (g33 = 40 [10-3Vm/N]) was developed to improve the figure of merit of the PZT ceramics. The cymbal composite transducer has been found as a promising structure for piezoelectric energy harvesting under high force at cyclic conditions (10--200 Hz), because it has almost 40 times higher effective strain coefficient than PZT ceramics. The endcap of cymbal also enhances the endurance of the ceramic to sustain ac load along with stress amplification. In addition, a macro fiber composite (MFC) was employed as a strain component because of its flexibility and the high electromechanical coupling factor. This characteristic is useful for a small force vibration source which has a high displacement such as human's activities. An experimental setup was used to apply the same conditions as a vibrating car engine. The experiment was done with a cymbal transducer which has 29 mm PZT diameter, 1mm PZT thickness, and 0.4mm endcap operating under force of 70 N in the frequency range of 10--200 Hz. It was found that the generated power was increased and the output impedance was decreased with a higher frequency of vibration source at a constant force. The experimental results were found to be in agreement with the analytical results from the model using the equivalent circuit. In addition, the FEM simulation (ATILA) was employed to optimize the dimensions of cymbal transducer such as endcap thickness and PZT thickness. Finally, the electrical impedance matching method used to increase the electrical to electrical energy transfer for some applications was discussed. To match the output impedance, two methods were employed: one is changing capacitance of transducer by size effect and multilayered ceramics, and another one is developing an energy harvesting circuit which consumes low electrical power and maximizes the output transferred to the intended load. The fabricated multilayered ceramics which has 10, 100 mum thick, layers yielded 10 times higher output current for 40 times reduced output load. Also the electrical output power was double. A DC-DC buck converter which has 78% efficiency was fabricated to transfer the accumulated electrical energy to the low output load without consuming more than 5 mW of power itself. In this DC-DC converter, most of the power was consumed by the gate drive which was required for PWM switching. To reduce the power consumption of the gate drive, the switching frequency was fixed at 1 kHz with optimal duty cycle around 1˜5%. Also the dependence of the inductance (L) in the DC-DC converter was investigated and optimized to increase the output power transferred to the small output load. Using this optimized DC-DC converter, two circ
Control of Vibratory Energy Harvesters in the Presence of Nonlinearities and Power-Flow Constraints
NASA Astrophysics Data System (ADS)
Cassidy, Ian L.
Over the past decade, a significant amount of research activity has been devoted to developing electromechanical systems that can convert ambient mechanical vibrations into usable electric power. Such systems, referred to as vibratory energy harvesters, have a number of useful of applications, ranging in scale from self-powered wireless sensors for structural health monitoring in bridges and buildings to energy harvesting from ocean waves. One of the most challenging aspects of this technology concerns the efficient extraction and transmission of power from transducer to storage. Maximizing the rate of power extraction from vibratory energy harvesters is further complicated by the stochastic nature of the disturbance. The primary purpose of this dissertation is to develop feedback control algorithms which optimize the average power generated from stochastically-excited vibratory energy harvesters. This dissertation will illustrate the performance of various controllers using two vibratory energy harvesting systems: an electromagnetic transducer embedded within a flexible structure, and a piezoelectric bimorph cantilever beam. Compared with piezoelectric systems, large-scale electromagnetic systems have received much less attention in the literature despite their ability to generate power at the watt--kilowatt scale. Motivated by this observation, the first part of this dissertation focuses on developing an experimentally validated predictive model of an actively controlled electromagnetic transducer. Following this experimental analysis, linear-quadratic-Gaussian control theory is used to compute unconstrained state feedback controllers for two ideal vibratory energy harvesting systems. This theory is then augmented to account for competing objectives, nonlinearities in the harvester dynamics, and non-quadratic transmission loss models in the electronics. In many vibratory energy harvesting applications, employing a bi-directional power electronic drive to actively control the harvester is infeasible due to the high levels of parasitic power required to operate the drive. For the case where a single-directional drive is used, a constraint on the directionality of power-flow is imposed on the system, which necessitates the use of nonlinear feedback. As such, a sub-optimal controller for power-flow-constrained vibratory energy harvesters is presented, which is analytically guaranteed to outperform the optimal static admittance controller. Finally, the last section of this dissertation explores a numerical approach to compute optimal discretized control manifolds for systems with power-flow constraints. Unlike the sub-optimal nonlinear controller, the numerical controller satisfies the necessary conditions for optimality by solving the stochastic Hamilton-Jacobi equation.
Hybrid energy harvesting/transmission system for embedded devices
NASA Astrophysics Data System (ADS)
Hehr, Adam; Park, Gyuhae; Farinholt, Kevin
2012-04-01
In most energy harvesting applications the need for a reliable long-term energy supply is essential in powering embedded sensing and control electronics. The goal of many harvesters is to extract energy from the ambient environment to power hardware; however in some applications there may be conditions in which the harvester's performance cannot meet all of the demands of the embedded electronics. One method for addressing this shortfall is to supplement harvested power through the transmission of wireless energy, a concept that has successfully been demonstrated by the authors in previous studies. In this paper we present our findings on the use of a single electromagnetic coil to harvest kinetic energy in a solenoid configuration, as well as background and directed wireless energy in the 2.4 GHz radio frequency (RF) bands commonly used in WiFi and cellular phone applications. The motivation for this study is to develop a compact energy harvester / receiver that conserves physical volume, while providing multi-modal energy harvesting capabilities. As with most hybrid systems there are performance trade-offs that must be considered when capturing energy from different physical sources. As part of this paper, many of the issues related to power transmission, physical design, and potential applications are addressed for this device.
Energy harvesting in a nonlinear piezomagnetoelastic beam subjected to random excitation
NASA Astrophysics Data System (ADS)
De Paula, Aline S.; Inman, Daniel J.; Savi, Marcelo A.
2015-03-01
This work addresses the influence of nonlinearities in energy harvesting from a piezomagnetoelastic structure subjected to random vibrations. Nonlinear equations of motion that describe the electromechanical system are given along with theoretical simulations. The numerical analysis presents a comparison between the voltage provided from a linear, nonlinear bistable and nonlinear monostable systems due to random vibration. Experimental performance of the generator exhibits qualitative agreement with the theory, showing an enhancement of piezoelectric power generation in a bistable system when it vibrates around both stable equilibrium points. A relationship between variations in the excitation and a bistable system response is established from numerical simulations, defining a region of enhanced power generation when compared to the linear and nonlinear monostable cases.
NASA Astrophysics Data System (ADS)
Stanton, Samuel C.; McGehee, Clark C.; Mann, Brian P.
2010-05-01
Vibration energy harvesting research has largely focused on linear electromechanical devices excited at resonance. Considering that most realistic vibration environments are more accurately described as either stochastic, multi-frequency, time varying, or some combination thereof, narrowband linear systems are fated to be highly inefficient under these conditions. Nonlinear systems, on the other hand, are capable of responding over a broad frequency range; suggesting an intrinsic suitability for efficient performance in realistic vibration environments. Since a number of nonlinear dynamical responses emerge from dissipative systems undergoing a homoclinic saddle-point bifurcation, we validate this concept with a bistable inertial oscillator comprised of permanent magnets and a piezoelectric cantilever beam. The system is analytically modeled, numerically simulated, and experimentally realized to demonstrate enhanced capabilities and new challenges. In addition, a bifurcation parameter within the design is examined as either a fixed or an adaptable tuning mechanism for enhanced sensitivity to ambient excitation.
NASA Astrophysics Data System (ADS)
Remick, Kevin; Joo, Han Kyul; McFarland, D. Michael; Sapsis, Themistoklis P.; Bergman, Lawrence; Quinn, D. Dane; Vakakis, Alexander
2014-07-01
This work investigates a vibration-based energy harvesting system composed of two oscillators coupled with essential (nonlinearizable) stiffness nonlinearity and subject to impulsive loading of the mechanical component. The oscillators in the system consist of one grounded, weakly damped linear oscillator mass (primary system), which is coupled to a second light-weight, weakly damped oscillating mass attachment (the harvesting element) through a piezoelastic cable. Due to geometric/kinematic mechanical effects the piezoelastic cable generates a nonlinearizable cubic stiffness nonlinearity, whereas electromechanical coupling simply sees a resistive load. Under single and repeated impulsive inputs the transient damped dynamics of this system exhibit transient resonance captures (TRCs) causing high-frequency 'bursts' or instabilities in the response of the harvesting element. In turn, these high-frequency dynamic instabilities result in strong and sustained energy transfers from the directly excited primary system to the lightweight harvester, which, through the piezoelastic element, are harvested by the electrical component of the system or, in the present case, dissipated across a resistive element in the circuit. The primary goal of this work is to demonstrate the efficacy of employing this type of high-frequency dynamic instability to achieve enhanced nonlinear vibration energy harvesting under impulsive excitations.
Energy harvesting based on piezoelectric Ericsson cycles in a piezoceramic material
NASA Astrophysics Data System (ADS)
Zhang, B.; Ducharne, B.; Guyomar, D.; Sebald, G.
2013-09-01
The possibility of recycling ambient energies with electric generators instead of using batteries with limited life spans has stimulated important research efforts over the past years. The integration of such generators into mainly autonomous low-power systems, for various industrial or domestic applications is envisioned. In particular, the present work deals with energy harvesting from mechanical vibrations. It is shown here that direct piezoelectric energy harvesting (short circuiting on an adapted resistance, for example) leads to relatively weak energy levels that are insufficient for an industrial development. By coupling an electric field and mechanical excitation on Ericsson-based cycles, the amplitude of the harvested energy can be highly increased, and can reach a maximum close to 100 times its initial value. To obtain such a gain, one needs to employ high electrical field levels (high amplitude, high frequency), which induce a non-linearity through the piezoceramic. A special dynamic hysteresis model has been developed to correctly take into account the material properties, and to provide a real estimation of the harvested energy. A large number of theoretical predictions and experimental results have been compared and are discussed herein, in order to validate the proposed solution.
Response analysis of a nonlinear magnetoelectric energy harvester under harmonic excitation
NASA Astrophysics Data System (ADS)
Naifar, S.; Bradai, S.; Viehweger, C.; Kanoun, O.
2015-11-01
Magnetostrictive (MS) piezoelectric composites provide interesting possibilities to harvest energy from low amplitude and low frequency vibrations with a relative high energy outcome. In this paper a magnetoelectric (ME) vibration energy harvester has been designed, which consists of two ME transducers a magnetic circuit and a magnetic spring. The ME transducers consist of three layered Terfenol-D and Lead Zirconate Titanate (PZT) laminated composites. The outcoming energy is collected directly from the piezo layer to avoid electrical losses. In the system under consideration, the magnetic forces between the ME transducers and the magnetic circuit introduce additional stiffness on the magnetic spring. The one degree of freedom system is analysed analytically and the corresponding governing equation is solved with the Lindstedt-Poincaré method. The effects of the structure parameters, such as the nonlinear magnetic forces and the magnetic field distribution, are analysed based on finite element analysis for optimization of electric output performances. Investigations demonstrate that 1.56 mW output power across 8 M? load resistance can be harvested for an excitation amplitude of 1 mm at 21.84 Hz.
Design and characterization of an electromagnetic energy harvester for vehicle suspensions
NASA Astrophysics Data System (ADS)
Zuo, Lei; Scully, Brian; Shestani, Jurgen; Zhou, Yu
2010-04-01
During the everyday usage of an automobile, only 10-16% of the fuel energy is used to drive the car—to overcome the resistance from road friction and air drag. One important loss is the dissipation of vibration energy by shock absorbers in the vehicle suspension under the excitation of road irregularity and vehicle acceleration or deceleration. In this paper we design, characterize and test a retrofit regenerative shock absorber which can efficiently recover the vibration energy in a compact space. Rare-earth permanent magnets and high permeable magnetic loops are used to configure a four-phase linear generator with increased efficiency and reduced weight. The finite element method is used to analyze the magnetic field and guide the design optimization. A theoretical model is created to analytically characterize the waveforms and regenerated power of the harvester at various vibration amplitudes, frequencies, equilibrium positions and design parameters. It was found that the waveform and RMS voltage of the individual coils will depend on the equilibrium position but the total energy will not. Experimental studies of a 1:2 scale prototype are conducted and the results agree very well with the theoretical predictions. Such a regenerative shock absorber will be able to harvest 16-64 W power at 0.25-0.5 m s - 1 RMS suspension velocity.
Energy harvesting cycles based on electro active polymers
NASA Astrophysics Data System (ADS)
Graf, Christian; Maas, Jürgen; Schapeler, Dirk
2010-04-01
Energy harvesting using dielectric elastomers is an interesting possibility to convert ambient energy into electric energy. Different small scale prototypes of energy harvesting devices, like SRIs wind- and wave-power generators have been developed so far. Nevertheless, the theoretical limits and practical implementation still have to be considered. The contribution of this paper is related to the calculation of the achievable energy gain. Different harvesting cycles are investigated theoretically and compared to each other. Based on the derived equations, several design rules for the material development are quoted. To analyze the various properties of dielectric elastomer generators an electromechanical test bench is realized. The design of an appropriate HV power electronics for energy harvesting devices is presented in the last section.
The effects of width reduction on cantilever type piezoelectric energy harvesters
NASA Astrophysics Data System (ADS)
Im, Jongbeom; Zhai, Linding; Dayou, Jedol; Kim, Jeong-Woong; Kim, Jaehwan
2015-04-01
In this paper, energy harvesting capability is examined by changing the width of cantilever beam and piezoelectric cellulose. It is started from hypothesis that if cantilever piezoelectric energy harvester with given width are split, it would increase power output due to the fact that the divided pieces have smaller damping ratio than the original single piece, in turn, they are supposed to vibrate with high amplitude at resonance frequency. In the experiment, as a piezoelectric material, cellulose Piezo Paper is prepared with aluminum electrode deposition. By attaching the Piezo Paper on an aluminum beam, a cantilever type piezoelectric energy harvester is made. The given width of the beam is 5cm, and sets of Piezo Papers with different width and number of beams are made as, 5cm x 1, 2.5cm x 2, 1.66cm x 3, 1.25cm x 4, 1cm x 5 and 0.83cm x 6 beams. Cantilever beams are vibrated on a shaker at its resonance frequency and examined their electrical characteristics in terms of output voltage and current. The results are compared with the original beam of 5 cm wide.
NASA Astrophysics Data System (ADS)
Bryant, Matthew; Wolff, Eric; Garcia, Ephrahim
2011-12-01
This study examines the design parameters affecting the stability characteristics of a novel fluid flow energy harvesting device powered by aeroelastic flutter vibrations. The energy harvester makes use of a modal convergence flutter instability to generate limit cycle bending oscillations of a cantilevered piezoelectric beam with a small flap connected to its free end by a revolute joint. The critical flow speed at which destabilizing aerodynamic effects cause self-excited vibrations of the structure to emerge is essential to the design of the energy harvester because it sets the lower bound on the operating wind speed and frequency range of the system. A linearized analytic model of the device that accounts for the three-way coupling between the structural, unsteady aerodynamic, and electrical aspects of the system is used to examine tuning several design parameters while the size of the system is held fixed. The effects on the aeroelastic system dynamics and relative sensitivity of the flutter stability boundary are presented and discussed. A wind tunnel experiment is performed to validate the model predictions for the most significant system parameters.
Modeling and design of Galfenol unimorph energy harvesters
NASA Astrophysics Data System (ADS)
Deng, Zhangxian; Dapino, Marcelo J.
2015-12-01
This article investigates the modeling and design of vibration energy harvesters that utilize iron-gallium (Galfenol) as a magnetoelastic transducer. Galfenol unimorphs are of particular interest; however, advanced models and design tools are lacking for these devices. Experimental measurements are presented for various unimorph beam geometries. A maximum average power density of 24.4 {mW} {{cm}}-3 and peak power density of 63.6 {mW} {{cm}}-3 are observed. A modeling framework with fully coupled magnetoelastic dynamics, formulated as a 2D finite element model, and lumped-parameter electrical dynamics is presented and validated. A comprehensive parametric study considering pickup coil dimensions, beam thickness ratio, tip mass, bias magnet location, and remanent flux density (supplied by bias magnets) is developed for a 200 Hz, 9.8 {{m}} {{{s}}}-2 amplitude harmonic base excitation. For the set of optimal parameters, the maximum average power density and peak power density computed by the model are 28.1 and 97.6 {mW} {{cm}}-3, respectively.
Assessment of MEMS energy harvester for medical applications
NASA Astrophysics Data System (ADS)
Smilek, Jan; Hadas, Zdenek
2015-05-01
This paper assesses the feasibility of the energy harvesting principle for the development of an autonomous power supply unit for a new generation of biomedical devices, e.g. artificial cochlear implants. Requirements for the harvester are set based on a research of power demands of state-of-the-art medical devices. Feasible methods of the energy conversion are then reviewed, and a simulation model of the generic energy harvester is developed. Acceleration in the head area of the user is measured and used as an input excitation for the model. Possible course of the follow-up research is outlined based on simulation and measurement results.
Park, Jongcheol; Park, Jae Yeong
2013-10-01
A piezoelectric vibration energy harvester with inter-digital IrO(x) electrode was developed by using silicon bulk micromachining technology. Most PZT cantilever based energy harvesters have utilized platinum electrode material. However, the PZT fatigue characteristics and adhesion/delamination problems caused by the platinum electrode might be serious problem in reliability of energy harvester. To address these problems, the iridium oxide was newly applied. The proposed energy harvester was comprised of bulk micromachined silicon cantilever with 800 x 1000 x 20 microm3, which having a silicon supporting membrane, sol-gel-spin coated Pb(Zr52, Ti48)O3 thin film, and sputtered inter-digitally shaped IrO(x) electrodes, and silicon inertial mass with 1000 x 1000 x 500 microm3 to adjust its resonant frequency. The fabricated energy harvester generated 1 microW of electrical power to 470 komega of load resistance and 1.4 V(peak-to-peak) from a vibration of 0.4 g at 1.475 kHz. The corresponding power density was 6.25 mW x cm(-3) x g(-2). As expected, its electrical failure was significantly improved. PMID:24245226
Innovative thermal energy harvesting for future autonomous applications
NASA Astrophysics Data System (ADS)
Monfray, Stephane
2013-12-01
As communicating autonomous systems market is booming, the role of energy harvesting will be a key enabler. As example, heat is one of the most abundant energy sources that can be converted into electricity in order to power circuits. Harvesting systems that use wasted heat open new ways to power autonomous sensors when the energy consumption is low, or to create systems of power generators when the conversion efficiency is high. The combination of different technologies (low power ?-processors, ?-batteries, radio, sensors...) with new energy harvesters compatible with large varieties of use-cases with allow to address this booming market. Thanks to the conjunction of ultra-low power electronic development, 3D technologies & Systems in Package approaches, the integration of autonomous sensors and electronics with ambient energy harvesting will be achievable. The applications are very wide, from environment and industrial sensors to medical portable applications, and the Internet of things may also represent in the future a several billions units market.
Flexible piezoelectric thin-film energy harvesters and nanosensors for biomedical applications.
Hwang, Geon-Tae; Byun, Myunghwan; Jeong, Chang Kyu; Lee, Keon Jae
2015-04-01
The use of inorganic-based flexible piezoelectric thin films for biomedical applications has been actively reported due to their advantages of highly piezoelectric, pliable, slim, lightweight, and biocompatible properties. The piezoelectric thin films on plastic substrates can convert ambient mechanical energy into electric signals, even responding to tiny movements on corrugated surfaces of internal organs and nanoscale biomechanical vibrations caused by acoustic waves. These inherent properties of flexible piezoelectric thin films enable to develop not only self-powered energy harvesters for eliminating batteries of bio-implantable medical devices but also sensitive nanosensors for in vivo diagnosis/therapy systems. This paper provides recent progresses of flexible piezoelectric thin-film harvesters and nanosensors for use in biomedical fields. First, developments of flexible piezoelectric energy-harvesting devices by using high-quality perovskite thin film and innovative flexible fabrication processes are addressed. Second, their biomedical applications are investigated, including self-powered cardiac pacemaker, acoustic nanosensor for biomimetic artificial hair cells, in vivo energy harvester driven by organ movements, and mechanical sensor for detecting nanoscale cellular deflections. At the end, future perspective of a self-powered flexible biomedical system is also briefly discussed with relation to the latest advancements of flexible electronics. PMID:25476410
Fokker-Planck equation analysis of randomly excited nonlinear energy harvester
NASA Astrophysics Data System (ADS)
Kumar, P.; Narayanan, S.; Adhikari, S.; Friswell, M. I.
2014-03-01
The probability structure of the response and energy harvested from a nonlinear oscillator subjected to white noise excitation is investigated by solution of the corresponding Fokker-Planck (FP) equation. The nonlinear oscillator is the classical double well potential Duffing oscillator corresponding to the first mode vibration of a cantilever beam suspended between permanent magnets and with bonded piezoelectric patches for purposes of energy harvesting. The FP equation of the coupled electromechanical system of equations is derived. The finite element method is used to solve the FP equation giving the joint probability density functions of the response as well as the voltage generated from the piezoelectric patches. The FE method is also applied to the nonlinear inductive energy harvester of Daqaq and the results are compared. The mean square response and voltage are obtained for different white noise intensities. The effects of the system parameters on the mean square voltage are studied. It is observed that the energy harvested can be enhanced by suitable choice of the excitation intensity and the parameters. The results of the FP approach agree very well with Monte Carlo Simulation (MCS) results.
Piezoelectric energy-harvesting power source and event detection sensors for gun-fired munitions
NASA Astrophysics Data System (ADS)
Rastegar, Jahangir; Feng, Dake; Pereira, Carlos M.
2015-05-01
This paper presents a review of piezoelectric based energy harvesting devices and their charge collection electronics for use in very harsh environment of gun-fired munitions. A number of novel classes of such energy harvesting power sources have been developed for gun-fired munitions and similar applications, including those with integrated safety and firing setback event detection electronics and logic circuitry. The power sources are designed to harvest energy from firing acceleration and vibratory motions during the flight. As an example, the application of the developed piezoelectric based energy harvesting devices with event detection circuitry for the development of self-powered initiators with full no-fire safety circuitry for protection against accidental drops, transportation vibration, and other similar low amplitude accelerations and/or high amplitude but short duration acceleration events is presented. The design allows the use of a very small piezoelectric element, thereby allowing such devices to be highly miniaturized. These devices can be readily hardened to withstand very high G firing setback accelerations in excess of 100,000 G and the harsh firing environment. The design of prototypes and testing under realistic conditions are presented.
High temperature energy harvester for wireless sensors
NASA Astrophysics Data System (ADS)
Köhler, J. E.; Heijl, R.; Staaf, L. G. H.; Zenkic, S.; Svenman, E.; Lindblom, A.; Palmqvist, A. E. C.; Enoksson, P.
2014-09-01
Implementing energy harvesters and wireless sensors in jet engines will simplify development and decrease costs by reducing the need for cables. Such a device could include a small thermoelectric generator placed in the cooling channels of the jet engine where the temperature is between 500-900 °C. This paper covers the synthesis of suitable thermoelectric materials, design of module and proof of concept tests of a thermoelectric module. The materials and other design variables were chosen based on an analytic model and numerical analysis. The module was optimized for 600-800 °C with the thermoelectric materials n-type Ba8Ga16Ge30 and p-type La-doped Yb14MnSb11, both with among the highest reported figure-of-merit values, zT, for bulk materials in this region. The materials were synthesized and their structures confirmed by x-ray diffraction. Proof of concept modules containing only two thermoelectric legs were built and tested at high temperatures and under high temperature gradients. The modules were designed to survive an ambient temperature gradient of up to 200 °C. The first measurements at low temperature showed that the thermoelectric legs could withstand a temperature gradient of 123 °C and still be functional. The high temperature measurement with 800 °C on the hot side showed that the module remained functional at this temperature.
Harvesting energy from water flow over graphene?
Yin, Jun; Zhang, Zhuhua; Li, Xuemei; Zhou, Jianxin; Guo, Wanlin
2012-03-14
It is reported excitingly in a previous letter (Nano Lett. 2011, 11, 3123) that a small piece of graphene sheet about 30 × 16 ?m(2) immersed in flowing water with 0.6 M hydrochloric acid can produce voltage ~20 mV. Here we find that no measurable voltage can be induced by the flow over mono-, bi- and trilayered graphene samples of ~1 × 1.5 cm(2) in size in the same solution once the electrodes on graphene are isolated from interacting with the solution, mainly because the H(3)O(+) cations in the water adsorb onto graphene by strong covalent bonds as revealed by our first-principles calculations. When both the graphene and its metal electrodes are exposed to the solution as in the previous work, water flow over the graphene-electrode system can induce voltages from a few to over a hundred millivolts. In this situation, the graphene mainly behaves as a load connecting between the electrodes. Therefore, the harvested energy is not from the immersed carbon nanomaterials themselves in ionic water flow but dominated by the exposed electrodes. PMID:22381077
Harvesting Residuals-Economic Energy Link
Owens, E. T.; Curtis, D. B.
1986-01-01
A description of systems used in integrated harvesting of quality and unmerchantable trees is outlined for three areas in New Brunswick, Canada. The silvicultural benefits and the use of residues as an alternative to ...
Piezoelectric and electromagnetic respiratory effort energy harvesters.
Shahhaidar, Ehsaneh; Padasdao, Bryson; Romine, R; Stickley, C; Boric-Lubecke, Olga
2013-01-01
The movements of the torso due to normal breathing could be harvested as an alternative, and renewable power source for an ultra-low power electronic device. The same output signal could also be recorded as a physiological signal containing information about breathing, thus enabling self-powered wearable biosensors/harvesters. In this paper, the selection criteria for such a biosensor, optimization procedure, trade-offs, and challenges as a sensor and harvester are presented. The empirical data obtained from testing different modules on a mechanical torso and a human subject demonstrated that an electromagnetic generator could be used as an unobtrusive self-powered medical sensor by harvesting more power, offering reasonable amount of output voltage for rectification purposes, and detecting respiratory effort. PMID:24110468
Piezoelectric Wind-Energy-Harvesting Device with Reed and Resonant Cavity
NASA Astrophysics Data System (ADS)
Ji, Jun; Kong, Fanrang; He, Liangguo; Guan, Qingchun; Feng, Zhihua
2010-05-01
A wind-energy-harvesting device utilizing the principle of a harmonica was created. A reed in a resonant cavity vibrated efficiently with the blowing wind, and a piezoelectric element stuck on the reed generated electricity. The dimensions of the wind inlet were approximately 30×20 mm2. The device was investigated with a wind speed ranging from 2.8 to 10 m/s. An output power of 0.5-4.5 mW was obtained with a matching load of 0.46 M?. The energy conversion efficiency of the device could reach up to 2.4%.
Evaluation of flexible transducers for motion energy harvesting
NASA Astrophysics Data System (ADS)
Collins, Michael; Behrens, Sam; McGarry, Scott
2009-03-01
Personal electronic devices such as mobile/cell phones, radios and wireless sensors traditionally depend on energy storage technologies, such as batteries, for operation. By harvesting energy from the local environment, these devices can achieve greater run-times without the need for battery recharging or replacement. Harvesting energy could also achieve a reduction in the weight and volume of the personal devices - as batteries often make up more than half the weight/volume of these devices. Motion energy harvesting is one such approach where energy from mechanical motion can be converted into electrical energy. This can be achieved through the use of flexible piezoelectric transducer materials such as polyvinylidene fluoride (PVDF). A problem with these transducer materials it that their behaviour is non-linear due to operating and environmental conditions. Hence, for this reason researchers have found it has been difficult to measure the harvesting performance i.e. mechanical-to-electrical conversion efficiency. At CSIRO we are currently evaluating the performance of flexible transducers for use as motion energy harvesters. Preliminary results suggest an overall energy harvesting conversion efficiency of 0.65% for a flexible transducer material.
Modeling of a honeycomb-shaped pyroelectric energy harvester for human body heat harvesting
NASA Astrophysics Data System (ADS)
Kim, Myoung-Soo; Jo, Sung-Eun; Ahn, Hye-Rin; Kim, Yong-Jun
2015-06-01
Pyroelectric conversion can be used for thermal energy harvesting in lieu of thermoelectric conversion. In the case of human body energy harvesting, the general pyroelectric energy harvester (PEH) cannot be applied because the weak body heat can hardly penetrate the protecting layer to reach the pyroelectric material. This paper presents the realization of a honeycomb-shaped PEH (H-PEH) and a modeling method of the electrode and hole areas. The fabricated H-PEH successfully generated electrical energy using human body heat. The H-PEH with a 1:1.5 electrode-and-hole area ratio showed the best performance. To verify the human energy harvesting, we evaluated the characteristics of conventional PEH and H-PEH when body heat was used as a heat source. The maximum power of the H-PEH was 0.06 and 0.16 ?W at wind velocities of 2 and 4 m s-1, respectively. These output power values of the H-PEH were 200 and 224% larger than those of the PEH, respectively, according to the wind velocity.
Evaluation of smart-fabric approach to biomechanical energy harvesting
Denault, Sebastian Ramirez
2014-01-01
This thesis evaluates the proposed use of piezoelectric energy harvesting methods as a power source for light-up sneakers. Light-up sneakers currently marketed for purposes of pedestrian visibility and personal fashion are ...
Fundamental study of mechanical energy harvesting using piezoelectric nanostructures
Wang, Xudong
piezoelectricity generated on the NW side surfaces. Perturbation theory and finite elements method have beenFundamental study of mechanical energy harvesting using piezoelectric nanostructures Chengliang Sun efficiency of piezoelectric nanostructures, including rectangular nanowires NWs , hexagonal NWs, and two
Design of test bench apparatus for piezoelectric energy harvesters
Yoon, You C. (You Chang)
2013-01-01
This thesis presents the design and analysis of an experimental test bench for the characterization of piezoelectric microelectromechanical system (MEMS) energy harvester being developed by the Micro & Nano Systems Laboratory ...
Microbial fuel cell energy harvesting using synchronous flyback converter
NASA Astrophysics Data System (ADS)
Alaraj, Muhannad; Ren, Zhiyong Jason; Park, Jae-Do
2014-02-01
Microbial Fuel Cells (MFCs) use biodegradable substrates, such as wastewater and marine sediments to generate electrical energy. To harvest more energy from an MFC, power electronic converters have recently been used to replace resistors or charge pumps, because they have superior controllability on MFC's operating point and higher efficiency in energy storage for different applications. Conventional diode-based energy harvesters suffer from low efficiency because of the energy losses through the diode. Replacing the diode with a MOSFET can reduce the conduction loss, but it requires an isolated gate signal to control the floating secondary MOSFET, which makes the control circuitry complex. This study presents a new MFC energy harvesting regime using a synchronous flyback converter, which implements a transformer-based harvester with much simpler configuration and improves harvesting efficiency by 37.6% compared to a diode based boost converter, from 33.5% to 46.1%. The proposed harvester was able to store 2.27 J in the output capacitor out of 4.91 J generated energy from the MFC, while the boost converter can capture 1.67 J from 4.95 J.
Zhang, Zhedong
2015-01-01
Recently the quantum nature in the energy transport in solar cell and light-harvesting complexes have attracted much attention, as being triggered by the experimental observations. We model the light-harvesting complex (i.e., PEB50 dimer) as a quantum heat engine (QHE) and study the effect of the undamped intra-molecule vibrational modes on the coherent energy transfer process and quantum transport. We find that the exciton-vibration interaction has non-trivial contribution to the promotion of quantum yield as well as transport properties of the quantum heat engine at steady state, by enhancing the quantum coherence quantified by entanglement entropy. The perfect quantum yield over 90% has been obtained, with theexciton-vibration coupling. We attribute these improvements to the renormalization of the electronic couplings effectively induced by exciton-vibration interaction and the subsequent delocalization of excitons. Finally we demonstrate that the thermal relaxation and dephasing can help the excitation en...
Non-resonant electromechanical energy harvesting using inter-ferroelectric phase transitions
NASA Astrophysics Data System (ADS)
Pérez Moyet, Richard; Stace, Joseph; Amin, Ahmed; Finkel, Peter; Rossetti, George A.
2015-10-01
Non-resonant electromechanical energy harvesting is demonstrated under low frequency excitation (<50 Hz) using [110]C-poled lead indium niobate-lead magnesium niobate-lead titanate relaxor ferroelectric single crystals with compositions near the morphotropic phase boundary. The efficiency of power generation at the stress-induced phase transition between domain-engineered rhombohedral and orthorhombic ferroelectric states is as much as four times greater than is obtained in the linear piezoelectric regime under identical measurement conditions but during loading below the coercive stress of the phase change. The phase transition mode of electromechanical transduction holds potential for non-resonant energy harvesting from low-frequency vibrations and does not require mechanical frequency up-conversion.
Hybrid energy harvester based on nanopillar solar cells and PVDF nanogenerator.
Lee, Dae-Yeong; Kim, Hyunjin; Li, Hua-Min; Jang, A-Rang; Lim, Yeong-Dae; Cha, Seung Nam; Park, Young Jun; Kang, Dae Joon; Yoo, Won Jong
2013-05-01
A tandem device which integrates a PVDF nanogenerator and silicon (Si) nanopillar solar cell is fabricated. The Si nanopillar solar cell was fabricated using a mask-free plasma etching technique and annealing process. The PVDF nanogenerator was stacked on top of the Si nanopillar solar cell using a spinning method. The optical properties and the device performance of nanowire solar cells have been characterized, and the dependence of device performance versus annealing time or method has been investigated. Furthermore, the PVDF nanogenerator was operated with a 100 dB sound wave and a 0.8 V peak to peak output voltage was generated. This tandem device can successfully harvest energy from both sound vibration and solar light, demonstrating its strong potential as a future ubiquitous energy harvester. PMID:23558434
Interplay between electrical and mechanical domains in a high performance nonlinear energy harvester
NASA Astrophysics Data System (ADS)
Mallick, Dhiman; Amann, Andreas; Roy, Saibal
2015-12-01
This paper reports a comprehensive experimental characterization and modeling of a compact nonlinear energy harvester for low frequency applications. By exploiting the interaction between the electrical circuitry and the mechanical motion of the device, we are able to improve the power output over a large frequency range. This improvement is quantified using a new figure of merit based on a suitably defined ‘power integral (P f)’ for nonlinear vibrational energy harvesters. The developed device consists of beams with fixed-guided configuration which produce cubic monostable nonlinearity due to stretching strain. Using a high efficiency magnetic circuit a maximum output power of 488.47 ?W across a resistive load of 4000 ? under 0.5g input acceleration at 77 Hz frequency with 9.55 Hz of bandwidth is obtained. The dynamical characteristics of the device are theoretically reproduced and explained by a modified nonlinear Duffing oscillator model.
Underwater energy harvesting from a heavy flag hosting ionic polymer metal composites
NASA Astrophysics Data System (ADS)
Giacomello, Alberto; Porfiri, Maurizio
2011-04-01
In this paper, we analyze underwater energy harvesting from the flutter instability of a heavy flag hosting an ionic polymer metal composite (IPMC). The heavy flag comprises a highly compliant membrane with periodic metal reinforcements to maximize the weight and minimize the bending stiffness, thus promoting flutter at moderately low flow speed. The IPMC is mechanically attached to the host flag and connected to an external load. The entire structure is immersed in a mean flow whose intensity is parametrically varied to explore the onset of flutter instability along with the relation between the vibration frequency and the mean flow speed. Manageable theoretical models for fluid-structure interaction and IPMC response are presented to inform the harvester design and interpret experimental data. Further, optimal parameters for energy scavenging maximization, including resistive load and flow conditions, are identified.
NASA Astrophysics Data System (ADS)
Giacomello, Alberto; Porfiri, Maurizio
2011-04-01
In this paper, we analyze underwater energy harvesting from the flutter instability of a heavy flag hosting an ionic polymer metal composite (IPMC). The heavy flag comprises a highly compliant membrane with periodic metal reinforcements to maximize the weight and minimize the bending stiffness, thus promoting flutter at moderately low flow speed. An IPMC strip is mechanically attached to the host flag and connected to an external load. The entire structure is immersed in a background flow whose intensity is parametrically varied to explore the onset of flutter instability along with the relation between the vibration frequency and the mean flow speed. Manageable theoretical models for fluid-structure interaction and IPMC response are presented to inform the harvester design and interpret experimental data. Further, optimal parameters for energy scavenging maximization, including resistive load and flow conditions, are identified.
Modeling on energy harvesting from a railway system using piezoelectric transducers
NASA Astrophysics Data System (ADS)
Wang, Jianjun; Shi, Zhifei; Xiang, Hongjun; Song, Gangbing
2015-10-01
Theoretical models of piezoelectric energy harvesting from railway systems using patch-type and stack-type piezoelectric transducers are studied. An infinite Euler-Bernoulli beam on a Winkler foundation subjected to moving multi-loads is adopted to describe the dynamic behavior of railway track. The voltage and electric power of piezoelectric transducers installed at the bottom of a steel rail are derived analytically. Comparisons with earlier works and experimental results are given, indicating that the present solutions are reliable. Additionally, a parametric study is conducted to discuss the effects of axle loads, running velocity and load resistors on the solutions. The numerical results show that patch-type and stack-type piezoelectric transducers can harvest the available energy from track vibration to supply power for a wireless sensor network node and can also serve as sensors to monitor basic train information, such as the running velocity, the location and the axle load. The present investigations provide a theoretical guide in the design of piezoelectric patch and stack energy harvesters used in railway systems, which can serve as power sources for distributed wireless sensor networks in remote areas. The research results also demonstrate the potential of piezoelectric patches and stack harvesters in designing self-powered wireless sensor networks used in railway systems to ensure train operation safety.
Cao, Jianshu
Efficient energy transfer in light-harvesting systems, I: optimal temperature, reorganization of efficient and robust energy transfer in light-harvesting systems provides new insights for the optimal dynamics in light harvesting systems and energy transfer efficiency 2. Optimization in the Haken
Optimal Design of RF Energy Harvesting Device Using Genetic Algorithm
NASA Astrophysics Data System (ADS)
Mori, T.; Sato, Y.; Adriano, R.; Igarashi, H.
2015-11-01
This paper presents optimal design of an RF energy harvesting device using genetic algorithm (GA). In the present RF harvester, a planar spiral antenna (PSA) is loaded with matching and rectifying circuits. On the first stage of the optimal design, the shape parameters of PSA are optimized using . Then, the equivalent circuit of the optimized PSA is derived for optimization of the circuits. Finally, the parameters of RF energy harvesting circuit are optimized to maximize the output power using GA. It is shown that the present optimization increases the output power by a factor of five. The manufactured energy harvester starts working when the input electric field is greater than 0.5 V/m.
Single stage AC-DC converter for Galfenol-based micro-power energy harvesters
NASA Astrophysics Data System (ADS)
Cavaroc, Peyton; Curtis, Chandra; Naik, Suketu; Cooper, James
2014-06-01
Military based sensor systems are often hindered in operational deployment and/or other capabilities due to limitations in their energy storage elements. Typically operating from lithium based batteries, there is a finite amount of stored energy which the sensor can use to collect and transmit data. As a result, the sensors have reduced sensing and transmission rates. However, coupled with the latest advancements in energy harvesting, these sensors could potentially operate at standard sensing and transition rates as well as dramatically extend lifetimes. Working with the magnetostrictive material Galfenol, we demonstrate the production of enough energy to supplement and recharge a solid state battery thereby overcoming the deficiencies faced by unattended sensors. As with any vibration-based energy harvester, this solution produces an alternating current which needs to be rectified and boosted to a level conducive to recharge the storage element. This paper presents a power converter capable of efficiently converting an ultra-low AC voltage to a solid state charging voltage of 4.1VDC. While we are working with Galfenol transducers as our energy source, this converter may also be applied with any AC producing energy harvester, particularly at operating levels less than 2mW and 200mVAC.
Large-scale self-tuning solid-state kinetic energy harvester
NASA Astrophysics Data System (ADS)
Pletner, Baruch; Swan, Lukas; Wettels, Nicholas; Joseph, Alain
2012-04-01
In recent years there has been a strong emphasis on kinetic (vibration) energy harvesting using smart structure technology. This emphasis has been driven in large part by industry demand for powering sensors and wireless telemetry of sensor data in places into which running power and data cables is difficult or impossible. Common examples are helicopter drive shafts and other rotating equipment. In many instances, available space in these locations is highly limited, resulting in a trend for miniaturization of kinetic energy harvesters. While in some cases size limitations are dominant, in other cases large and even very large harvesters are possible and even desirable since they may produce significantly more power. Examples of large-scale energy harvesting include geomatics, which is the discipline of gathering, storing, processing, and delivering spatially referenced information on vast scales. Geomatics relies on suites of various sensors and imaging devices such as meteorological sensors, seismographs, high-resolution cameras, and LiDAR's. These devices may be stationed for prolonged periods of time in remote and poorly accessible areas and are required to operate continuously over prolonged periods of time. In other cases, sensing and imaging equipment may be mounted on land, sea, or airborne platforms and expected to operate for many hours on its own power. Providing power to this equipment constitutes a technological challenge. Other cases may include commercial buildings, unmanned powered gliders and more. Large scale kinetic energy harvesting thus constitutes a paradigm shift in the approach to kinetic energy harvesting as a whole and as often happens it poses its own unique technological challenges. Primarily these challenges fall into two categories: the cost-effective manufacturing of large and very large scale transducing elements based on smart structure technology and the continuous optimization (tuning) of these transducers for various operating conditions. Current research proposes the simultaneous solution of both of the aforementioned challenges via the use of specialized technology for the incorporation of large numbers of piezoelectric transducers into standard printed circuit boards and the continuous control of structural resonance via the application of adaptive compressive stress. Used together, these technologies allow for fully scalable and tunable kinetic energy harvesting. Since the design is modular in nature and a typical size of a single module can easily reach dimensions of 60 by 40 centimeters, there is virtually no upper limit on the size of the harvester other than the limits that derive from its specific applications and placement. The use of compressive forces rather than the commonly used non-structural mass for the tuning of the harvester frequency to the disturbing frequency allows for continuous adaptive tuning while at the same time avoiding the undesirable vibration damping effects of non-structural mass. A proof of concept large-scale harvester capable of manual compressive force tuning was built as part of the current study and preliminary tests were conducted. The tests validate the proposed approach showing power generation on the order of 10 mW at disturbing frequencies between 10 and 100 Hz, with RMS voltages reaching over 20 volts and RMS currents over 2 mA, with proven potential for 50 mW with over 100 VAC and 10 mA for a transducing panel 20 by 10 cm. The results also validate the tuning via compressive force approach, showing strong dependence of energy harvesting efficiency on the compressive force applied to the transducing panel.
A Shoe-Embedded Piezoelectric Energy Harvester for Wearable Sensors
Zhao, Jingjing; You, Zheng
2014-01-01
Harvesting mechanical energy from human motion is an attractive approach for obtaining clean and sustainable electric energy to power wearable sensors, which are widely used for health monitoring, activity recognition, gait analysis and so on. This paper studies a piezoelectric energy harvester for the parasitic mechanical energy in shoes originated from human motion. The harvester is based on a specially designed sandwich structure with a thin thickness, which makes it readily compatible with a shoe. Besides, consideration is given to both high performance and excellent durability. The harvester provides an average output power of 1 mW during a walk at a frequency of roughly 1 Hz. Furthermore, a direct current (DC) power supply is built through integrating the harvester with a power management circuit. The DC power supply is tested by driving a simulated wireless transmitter, which can be activated once every 2–3 steps with an active period lasting 5 ms and a mean power of 50 mW. This work demonstrates the feasibility of applying piezoelectric energy harvesters to power wearable sensors. PMID:25019634
Perlík, Václav; Cranston, Laura J; Cogdell, Richard J; Lincoln, Craig N; Savolainen, Janne; Šanda, František; Man?al, Tomáš; Hauer, Jürgen
2015-01-01
The initial energy transfer in photosynthesis occurs between the light-harvesting pigments and on ultrafast timescales. We analyze the carotenoid to bacteriochlorophyll energy transfer in LH2 Marichromatium purpuratum as well as in an artificial light-harvesting dyad system by using transient grating and two-dimensional electronic spectroscopy with 10 fs time resolution. We find that F\\"orster-type models reproduce the experimentally observed 60 fs transfer times, but overestimate coupling constants, which leads to a disagreement with both linear absorption and electronic 2D-spectra. We show that a vibronic model, which treats carotenoid vibrations on both electronic ground and excited state as part of the system's Hamiltonian, reproduces all measured quantities. Importantly, the vibronic model presented here can explain the fast energy transfer rates with only moderate coupling constants, which are in agreement with structure based calculations. Counterintuitively, the vibrational levels on the carotenoid el...
Hu, Youfan; Yang, Jin; Niu, Simiao; Wu, Wenzhuo; Wang, Zhong Lin
2014-07-22
The recently introduced triboelectric nanogenerator (TENG) and the traditional electromagnetic induction generator (EMIG) are coherently integrated in one structure for energy harvesting and vibration sensing/isolation. The suspended structure is based on two oppositely oriented magnets that are enclosed by hollow cubes surrounded with coils, which oscillates in response to external disturbance and harvests mechanical energy simultaneously from triboelectrification and electromagnetic induction. It extends the previous definition of hybrid cell to harvest the same type of energy with multiple approaches. Both the sliding-mode TENG and contact-mode TENG can be achieved in the same structure. In order to make the TENG and EMIG work together, transformers are used to match the output impedance between these two power sources with very different characteristics. The maximum output power of 7.7 and 1.9 mW on the same load of 5 k? was obtained for the TENG and EMIG, respectively, after impedance matching. Benefiting from the rational design, the output signal from the TENG and the EMIG are in phase. They can be added up directly to get an output voltage of 4.6 V and an output current of 2.2 mA in parallel connection. A power management circuit was connected to the hybrid cell, and a regulated voltage of 3.3 V with constant current was achieved. For the first time, a logic operation was carried out on a half-adder circuit by using the hybrid cell working as both the power source and the input digit signals. We also demonstrated that the hybrid cell can serve as a vibration isolator. Further applications as vibration dampers, triggers, and sensors are all promising. PMID:24924185
A Piezoelectric PZT Ceramic Mulitlayer Stack for Energy Harvesting Under Dynamic Forces
NASA Technical Reports Server (NTRS)
Xu, Tian-Bing; Siochi, Emilie J.; Kang, Jin Ho; Zuo, Lei; Zhou, Wanlu; Tang, Xiudong; Jiang, Xiaoning
2011-01-01
Piezoelectric energy harvesting transducers (PEHTs) are commonly used in motion/vibration energy scavenging devices. To date, most researchers have focused on energy harvesting at narrow bandwidths around the mechanical resonance frequency, and most piezoelectric harvesting devices reported in the literature have very low effective piezoelectric coefficient (d(sub eff)) (< 10(exp 4) pC/N). For instance, more than 80% of PEHT related papers are on transverse "31" mode cantilever beam type PEHTs (CBPEHTs) having piezoelectric coefficients of about 100 pC/N. The level of harvested electrical power for CBPEHTs is on the order of microW even at resonance mode. In order to harvest more electrical energy across broader bandwidth, high effective piezoelectric coefficient structures are needed. In this study, we investigate a "33" longitudinal mode, piezoelectric PZT ceramic multilayer stack (PZT-Stack) with high effective piezoelectric coefficient for high-performance PEHTs. The PZT-Stack is composed of 300 layers of 0.1 mm thick PZT plates, with overall dimensions of 32.4 mm X 7.0 mm X 7.0 mm. Experiments were carried out with dynamic forces in a broad bandwidth ranging from 0.5 Hz to 25 kHz. The measured results show that the effective piezoelectric coefficient of the PZT-stack is about 1 X 10(exp 5) pC/N at off-resonance frequencies and 1.39 X 10(exp 6) pC/N at resonance, which is order of magnitude larger than that of traditional PEHTs. The effective piezoelectric coefficients (d(sub eff)) do not change significantly with applied dynamic forces having root mean square (RMS) values ranging from 1 N to 40 N. In resonance mode, 231 mW of electrical power was harvested at 2479 Hz with a dynamic force of 11.6 N(sub rms), and 7.6 mW of electrical power was generated at a frequency of 2114 Hz with 1 N(sub rms) dynamic force. In off-resonance mode, an electrical power of 18.7 mW was obtained at 680 Hz with a 40 N(sub rms) dynamic force. A theoretical model of energy harvesting for the PZT-Stack is established. The modeled results matched well with experimental measurements. This study demonstrated that high effective piezoelectric coefficient structures enable PEHTs to harvest more electrical energy from mechanical vibrations or motions, suggesting an effective design for high-performance low-footprint PEHTs with potential applications in military, aerospace, and portable electronics. In addition, this study provides a route for using piezoelectric multilayer stacks for active or semi-active adaptive control to damp, harvest or transform unwanted dynamic vibrations into useful electrical energy.
Characterization of self-excited fluidic energy harvesters in uniform flows
NASA Astrophysics Data System (ADS)
Azadeh Ranjbar, Vahid; Cler, Coralie; Elvin, Niell; Andreopoulos, Yiannis
2013-11-01
Energy harvesters consisting of a low aspect-ratio hollow circular cylinder attached to the free end of a cantilevered beam which is partially covered by piezoelectric patches near its clamped end to produce electrical power output have been investigated experimentally and analytically. The unsteady nature of vortex shedding is described by the van der Pol equation, a non-conservative oscillator with non-linear damping, which models the near wake dynamics that is coupled with the harvester's equation of motion. This model helps to describe and predict the vortex induced vibration phenomena such as lock-in range, maximum amplitude of oscillations and extension of structural oscillations far away lock-in range with a better physical insight. Both free vibration and wind tunnel tests were carried out to characterize the harvester. Based on the wind tunnel tests data, there is a remarkable difference in magnitude and frequency of the lift force between stationary and oscillating cylinders subjected to stationary uniform flow. Moreover, maximum electrical power output occurs at a forcing frequency somewhat higher than the structural resonance frequency. These experimental results are in good agreement with the results of the mathematical model. Sponsored by NSF Grant: CBET #1033117.
Development of MEMS based pyroelectric thermal energy harvesters
NASA Astrophysics Data System (ADS)
Hunter, Scott R.; Lavrik, Nickolay V.; Bannuru, Thirumalesh; Mostafa, Salwa; Rajic, Slo; Datskos, Panos G.
2011-06-01
The efficient conversion of waste thermal energy into electrical energy is of considerable interest due to the huge sources of low-grade thermal energy available in technologically advanced societies. Our group at the Oak Ridge National Laboratory (ORNL) is developing a new type of high efficiency thermal waste heat energy converter that can be used to actively cool electronic devices, concentrated photovoltaic solar cells, computers and large waste heat producing systems, while generating electricity that can be used to power remote monitoring sensor systems, or recycled to provide electrical power. The energy harvester is a temperature cycled pyroelectric thermal-to-electrical energy harvester that can be used to generate electrical energy from thermal waste streams with temperature gradients of only a few degrees. The approach uses a resonantly driven pyroelectric capacitive bimorph cantilever structure that potentially has energy conversion efficiencies several times those of any previously demonstrated pyroelectric or thermoelectric thermal energy harvesters. The goals of this effort are to demonstrate the feasibility of fabricating high conversion efficiency MEMS based pyroelectric energy converters that can be fabricated into scalable arrays using well known microscale fabrication techniques and materials. These fabrication efforts are supported by detailed modeling studies of the pyroelectric energy converter structures to demonstrate the energy conversion efficiencies and electrical energy generation capabilities of these energy converters. This paper reports on the modeling, fabrication and testing of test structures and single element devices that demonstrate the potential of this technology for the development of high efficiency thermal-to-electrical energy harvesters.
Thermoelectric Energy Harvesting from Transient Ambient Temperature Gradients
NASA Astrophysics Data System (ADS)
Moser, André; Erd, Metin; Kostic, Milos; Cobry, Keith; Kroener, Michael; Woias, Peter
2012-06-01
We examine a thermoelectric harvester that converts electrical energy from the naturally occurring temperature difference between ambient air and large thermal storage capacitors such as building walls or the soil. For maximum power output, the harvester design is implemented in two steps: source matching of the thermal and electrical interfaces to the energy source (system level) followed by load matching of the generator to these interfaces (subsystem level). Therefore, we measure thermal source properties such as the temperature difference, the air velocity, and the cutoff frequency in two application scenarios (road tunnel and office building). We extend a stationary model of the harvester into the time domain to account for transient behavior of the source. Based on the model and the source measurements, we perform the source and load matching. The resulting harvester consists of a pin fin heat sink with a thermal resistance of 6.2 K/W and a cutoff frequency 2.5 times greater than that of the source, a thermoelectric generator, and a DC/DC step-up converter starting at a total temperature difference of only ? T = 1.2 K. In a final road tunnel field test, this optimized harvester converts 70 mJ of electrical energy per day without any direct solar irradiation. The energy provided by the harvester enables 415 data transmissions from a wireless sensor node per day.
Cooperative energy harvesting for long-endurance autonomous vehicle teams
NASA Astrophysics Data System (ADS)
Page, S. F.; Rogers, J. D.; May, K.; Myatt, D. R.; Hickman, D.; Smith, M. I.
2010-04-01
This paper considers the exploitation of energy harvesting technologies for teams of Autonomous Vehicles (AVs). Traditionally, the optimisation of information gathering tasks such as searching for and tracking new objects, and platform level power management, are only integrated at a mission-management level. In order to truly exploit new energy harvesting technologies which are emerging in both the commercial and military domains (for example the 'EATR' robot and next-generation solar panels), the sensor management and power management processes must be directly coupled. This paper presents a novel non-myopic sensor management framework which addresses this issue through the use of a predictive platform energy model. Energy harvesting opportunities are modelled using a dynamic spatial-temporal energy map and sensor and platform actions are optimised according to global team utility. The framework allows the assessment of a variety of different energy harvesting technologies and perceptive tasks. In this paper, two representative scenarios are used to parameterise the model with specific efficiency and energy abundance figures. Simulation results indicate that the integration of intelligent power management with traditional sensor management processes can significantly increase operational endurance and, in some cases, simultaneously improve surveillance or tracking performance. Furthermore, the framework is used to assess the potential impact of energy harvesting technologies at various efficiency levels. This provides important insight into the potential benefits that intelligent power management can offer in relation to improving system performance and reducing the dependency on fossil fuels and logistical support.
Multiphysics Simulation in the Development of Thermoelectric Energy Harvesting Systems
NASA Astrophysics Data System (ADS)
Nesarajah, Marco; Frey, Georg
2015-09-01
This contribution presents a model-based development process for thermoelectric energy harvesting systems. Such systems convert thermal energy into electrical energy and produce enough energy to supply low-power devices. Realizations require three main challenges to be solved: to guarantee optimal thermal connection of the thermoelectric generators, to find a good design for the energy harvesting system, and to find an optimal electrical connection. Therefore, a development process is presented here. The process is divided into different steps and supports the developer in finding an optimal thermoelectric energy harvesting system for a given heat source and given objectives (technical and economical). During the process, several steps are supported by simulation models. Based on developed model libraries in Modelica®/Dymola®, thermal, thermoelectrical, electrical, and control components can be modeled, integrated into different variants, and verified step by step before the system is physically built and finally validated. The process is illustrated by an example through all the steps.
Harvesting Energy from the Counterbalancing (Weaving) Movement in Bicycle Riding
Yang, Yoonseok; Yeo, Jeongjin; Priya, Shashank
2012-01-01
Bicycles are known to be rich source of kinetic energy, some of which is available for harvesting during speedy and balanced maneuvers by the user. A conventional dynamo attached to the rim can generate a large amount of output power at an expense of extra energy input from the user. However, when applying energy conversion technology to human powered equipments, it is important to minimize the increase in extra muscular activity and to maximize the efficiency of human movements. This study proposes a novel energy harvesting methodology that utilizes lateral oscillation of bicycle frame (weaving) caused by user weight shifting movements in order to increase the pedaling force in uphill riding or during quick speed-up. Based on the 3D motion analysis, we designed and implemented the prototype of an electro-dynamic energy harvester that can be mounted on the bicycle's handlebar to collect energy from the side-to-side movement. The harvester was found to generate substantial electric output power of 6.6 mW from normal road riding. It was able to generate power even during uphill riding which has never been shown with other approaches. Moreover, harvesting of energy from weaving motion seems to increase the economy of cycling by helping efficient usage of human power. PMID:23112598
Yang, Aichao; Li, Ping; Wen, Yumei; Yang, Chao; Wang, Decai; Zhang, Feng; Zhang, Jiajia
2015-06-01
A magnetic-field energy harvester using a low-frequency magneto-mechano-electric (MME) composite tuning-fork is proposed. This MME composite tuning-fork consists of a copper tuning fork with piezoelectric Pb(Zr(1-x)Ti(x))O3 (PZT) plates bonded near its fixed end and with NdFeB magnets attached at its free ends. Due to the resonance coupling between fork prongs, the MME composite tuning-fork owns strong vibration and high Q value. Experimental results show that the proposed magnetic-field energy harvester using the MME composite tuning-fork exhibits approximately 4 times larger maximum output voltage and 7.2 times higher maximum power than the conventional magnetic-field energy harvester using the MME composite cantilever. PMID:26133877
NASA Astrophysics Data System (ADS)
Yang, Aichao; Li, Ping; Wen, Yumei; Yang, Chao; Wang, Decai; Zhang, Feng; Zhang, Jiajia
2015-06-01
A magnetic-field energy harvester using a low-frequency magneto-mechano-electric (MME) composite tuning-fork is proposed. This MME composite tuning-fork consists of a copper tuning fork with piezoelectric Pb(Zr1-xTix)O3 (PZT) plates bonded near its fixed end and with NdFeB magnets attached at its free ends. Due to the resonance coupling between fork prongs, the MME composite tuning-fork owns strong vibration and high Q value. Experimental results show that the proposed magnetic-field energy harvester using the MME composite tuning-fork exhibits approximately 4 times larger maximum output voltage and 7.2 times higher maximum power than the conventional magnetic-field energy harvester using the MME composite cantilever.
Li, Hao; Zhang, Gaofei; Ma, Rui; You, Zheng
2014-01-01
An effective multisource energy harvesting system is presented as power supply for wireless sensor nodes (WSNs). The advanced system contains not only an expandable power management module including control of the charging and discharging process of the lithium polymer battery but also an energy harvesting system using the maximum power point tracking (MPPT) circuit with analog driving scheme for the collection of both solar and vibration energy sources. Since the MPPT and the power management module are utilized, the system is able to effectively achieve a low power consumption. Furthermore, a super capacitor is integrated in the system so that current fluctuations of the lithium polymer battery during the charging and discharging processes can be properly reduced. In addition, through a simple analog switch circuit with low power consumption, the proposed system can successfully switch the power supply path according to the ambient energy sources and load power automatically. A practical WSNs platform shows that efficiency of the energy harvesting system can reach about 75–85% through the 24-hour environmental test, which confirms that the proposed system can be used as a long-term continuous power supply for WSNs. PMID:25032233
Harvesting Chaparral Biomass for Energy--An Environmental Assessment1
Harvesting Chaparral Biomass for Energy--An Environmental Assessment1 Philip J. Riggan and Paul H and could provide a locally important alternative source of energy. CHAPARRAL BIOMASS Considerable amounts of potential energy are present in the biomass of some chaparral communi- ties. Biomass in mature Adenostoma
Harvesting Energy from Wastewater in a 2-Chamber
Harvesting Energy from Wastewater in a 2-Chamber Microbial Fuel Cell Sikandar Present day wastewater treatment plants utilize high amounts of energy and are costly to operate. These conventional wastewater treatment plants utilize aerobic bacteria. Organic material in wastewater contains energy that can
Energy Harvesting for Structural Health Monitoring Sensor Gyuhae Park1
Simunic, Tajana
for large-scale alternative energy generation using wind turbines and solar cells is mature technologyEnergy Harvesting for Structural Health Monitoring Sensor Networks Gyuhae Park1 , Tajana Rosing2 of California, San Diego La Jolla, CA 92093-0701 ABSTRACT This paper reviews the development of energy
Efficient Topology Design in Time-Evolving and Energy-Harvesting Wireless Sensor Networks
Wang, Yu
in ambient energy- harvesting technologies have made it possible to power WSNs from energy generated from. Even though energy-harvesting technology can power WSNs more perpetually than non-renewable energy
MARVEL: measured active rotational vibrational energy levels
NASA Astrophysics Data System (ADS)
Furtenbacher, Tibor; Császár, Attila G.; Tennyson, Jonathan
2007-10-01
An algorithm is proposed, based principally on an earlier proposition of Flaud and co-workers [Mol. Phys. 32 (1976) 499], that inverts the information contained in uniquely assigned experimental rotational-vibrational transitions in order to obtain measured active rotational-vibrational energy levels (MARVEL). The procedure starts with collecting, critically evaluating, selecting, and compiling all available measured transitions, including assignments and uncertainties, into a single database. Then, spectroscopic networks (SN) are determined which contain all interconnecting rotational-vibrational energy levels supported by the grand database of the selected transitions. Adjustment of the uncertainties of the lines is performed next, with the help of a robust weighting strategy, until a self-consistent set of lines and uncertainties is achieved. Inversion of the transitions through a weighted least-squares-type procedure results in MARVEL energy levels and associated uncertainties. Local sensitivity coefficients could be computed for each energy level. The resulting set of MARVEL levels is called active as when new experimental measurements become available the same evaluation, adjustment, and inversion procedure should be repeated in order to obtain more dependable energy levels and uncertainties. MARVEL is tested on the example of the H 217O isotopologue of water and a list of 2736 dependable energy levels, based on 8369 transitions, has been obtained.
Energy Harvesting for Structural Health Monitoring Sensor Networks
Park, G.; Farrar, C. R.; Todd, M. D.; Hodgkiss, T.; Rosing, T.
2007-02-26
This report has been developed based on information exchanges at a 2.5-day workshop on energy harvesting for embedded structural health monitoring (SHM) sensing systems that was held June 28-30, 2005, at Los Alamos National Laboratory. The workshop was hosted by the LANL/UCSD Engineering Institute (EI). This Institute is an education- and research-focused collaboration between Los Alamos National Laboratory (LANL) and the University of California, San Diego (UCSD), Jacobs School of Engineering. A Statistical Pattern Recognition paradigm for SHM is first presented and the concept of energy harvesting for embedded sensing systems is addressed with respect to the data acquisition portion of this paradigm. Next, various existing and emerging sensing modalities used for SHM and their respective power requirements are summarized, followed by a discussion of SHM sensor network paradigms, power requirements for these networks and power optimization strategies. Various approaches to energy harvesting and energy storage are discussed and limitations associated with the current technology are addressed. This discussion also addresses current energy harvesting applications and system integration issues. The report concludes by defining some future research directions and possible technology demonstrations that are aimed at transitioning the concept of energy harvesting for embedded SHM sensing systems from laboratory research to field-deployed engineering prototypes.
NASA Astrophysics Data System (ADS)
Jang, Munseon; Song, Seunghwan; Park, Yong-Hee; Yun, Kwang-Seok
2015-06-01
In this study, we propose and demonstrate a piezoelectric energy harvester with a shell cantilever for mechanical frequency up-conversion to generate electric power in a low-frequency vibration environment. The proposed device is composed of a clamped semicylindrical shell cantilever as a driving beam and a piezoelectric cantilever attached to the proof mass of the shell cantilever as a generating beam. The shell cantilever bends downward when the external acceleration is over the threshold value for buckling transition. When the acceleration direction is reversed, the shell cantilever makes abrupt stop at its initial position, inducing impact-like force on the generating beam and resulting in free vibration at high resonance frequencies. Experimental results show that a maximum power of 101 µW at 20 Hz can be obtained.
An optimized self-powered switching circuit for non-linear energy harvesting with low voltage output
NASA Astrophysics Data System (ADS)
Lallart, Mickaël; Guyomar, Daniel
2008-06-01
Harvesting energy from environmental sources has been of particular interest these last few years. Microgenerators that can power electronic systems are a solution for the conception of autonomous, wireless devices. They allow the removal of bulky and costly wiring, as well as complex maintenance and environmental issues for battery-powered systems. In particular, using piezoelectric generators for converting vibrational energy to electrical energy is an intensively investigated field. In this domain, it has been shown that the harvested energy can be greatly improved by the use of an original non-linear treatment of the piezoelectric voltage called SSHI (Synchronized Switch Harvesting on Inductor), which consists in intermittently switching the piezoelectric element on a resonant electrical network for a very short time. However, the integration of miniaturized microgenerators with low voltage output (e.g. MEMS microgenerators) has not been widely studied. In the case of low voltage output, the losses introduced by voltage gaps of discrete components such as diodes or transistors can no longer be neglected. Therefore the purpose of this paper is to propose a model that takes into account such losses as well as a new architecture for the SSHI energy harvesting circuit that limits such losses in the harvesting process. While most of the study uses an externally powered microcontroller for the non-linear treatment, this circuit is fully self-powered, thus providing an enhanced autonomous microgenerator. In particular this circuit aims at limiting the effect of non-linear components with a voltage gap such as diodes. It is shown both theoretically and experimentally that the harvested power can be significantly increased using such a circuit. In particular, experimental measurements performed on a cantilever beam show that the circuit allows a 160% increase of the harvested power compared to a standard energy harvesting circuit, while the classical implementation of the SSHI shows an increase of only 100% of the output power in the classical case.
Energy harvesting from human motion: exploiting swing and shock excitations
NASA Astrophysics Data System (ADS)
Ylli, K.; Hoffmann, D.; Willmann, A.; Becker, P.; Folkmer, B.; Manoli, Y.
2015-02-01
Modern compact and low power sensors and systems are leading towards increasingly integrated wearable systems. One key bottleneck of this technology is the power supply. The use of energy harvesting techniques offers a way of supplying sensor systems without the need for batteries and maintenance. In this work we present the development and characterization of two inductive energy harvesters which exploit different characteristics of the human gait. A multi-coil topology harvester is presented which uses the swing motion of the foot. The second device is a shock-type harvester which is excited into resonance upon heel strike. Both devices were modeled and designed with the key constraint of device height in mind, in order to facilitate the integration into the shoe sole. The devices were characterized under different motion speeds and with two test subjects on a treadmill. An average power output of up to 0.84 mW is achieved with the swing harvester. With a total device volume including the housing of 21 cm3 a power density of 40 ?W cm-3 results. The shock harvester generates an average power output of up to 4.13 mW. The power density amounts to 86 ?W cm-3 for the total device volume of 48 cm3. Difficulties and potential improvements are discussed briefly.
Non-resonant energy harvesting via an adaptive bistable potential
NASA Astrophysics Data System (ADS)
Haji Hosseinloo, Ashkan; Turitsyn, Konstantin
2016-01-01
Narrow bandwidth and easy detuning, inefficiency in broadband and non-stationary excitations, and difficulties in matching a linear harvester’s resonance frequency to low-frequency excitations at small scales, have convinced researchers to investigate nonlinear, and in particular bistable, energy harvesters in recent years. However, bistable harvesters suffer from co-existing low and high energy orbits, and sensitivity to initial conditions, and have recently been proven inefficient when subjected to many real-world random and non-stationary excitations. Here, we propose a novel non-resonant buy-low-sell-high strategy that can significantly improve the harvester’s effectiveness at low frequencies in a much more robust fashion. This strategy could be realized by a passive adaptive bistable system. Simulation results confirm the high effectiveness of the adaptive bistable system following a buy-low-sell-high logic when subjected to harmonic and random non-stationary walking excitations compared to its conventional bistable and linear counterparts.
Energy Aware Dynamic Voltage and Frequency Selection for Real-Time Systems with Energy Harvesting
Qiu, Qinru
Energy Aware Dynamic Voltage and Frequency Selection for Real-Time Systems with Energy Harvesting}@binghamton.edu Abstract In this paper, an energy aware dynamic voltage and frequency selection (EA-DVFS) algorithm energy and the harvested energy in a future duration. Specifically, if the system has sufficient energy
Hybrid energy cell for simultaneously harvesting wind, solar, and chemical energies
Wang, Zhong L.
Hybrid energy cell for simultaneously harvesting wind, solar, and chemical energies Yingchun Wu1 KEYWORDS hybrid energy cell, wind energy, solar energy, triboelectric nanogenerators, electrochemical cells ABSTRACT We report a hybrid energy cell that can simultaneously or individually harvest wind, solar
Long term performance of wearable transducer for motion energy harvesting
NASA Astrophysics Data System (ADS)
McGarry, Scott A.; Behrens, Sam
2010-04-01
Personal electronic devices such as cell phones, GPS and MP3 players have traditionally depended on battery energy storage technologies for operation. By harvesting energy from a person's motion, these devices may achieve greater run times without increasing the mass or volume of the electronic device. Through the use of a flexible piezoelectric transducer such as poly-vinylidene fluoride (PVDF), and integrating it into a person's clothing, it becomes a 'wearable transducer'. As the PVDF transducer is strained during the person's routine activities, it produces an electrical charge which can then be harvested to power personal electronic devices. Existing wearable transducers have shown great promise for personal motion energy harvesting applications. However, they are presently physically bulky and not ergonomic for the wearer. In addition, there is limited information on the energy harvesting performance for wearable transducers, especially under realistic conditions and for extended cyclic force operations - as would be experienced when worn. In this paper, we present experimental results for a wearable PVDF transducer using a person's measured walking force profile, which is then cycled for a prolonged period of time using an experimental apparatus. Experimental results indicate that after an initial drop in performance, the transducer energy harvesting performance does not substantially deteriorate over time, as less than 10% degradation was observed. Longevity testing is still continuing at CSIRO.
A Skin-attachable Flexible Piezoelectric Pulse Wave Energy Harvester
NASA Astrophysics Data System (ADS)
Yoon, Sunghyun; Cho, Young-Ho
2014-11-01
We present a flexible piezoelectric generator, capable to harvest energy from human arterial pulse wave on the human wrist. Special features and advantages of the flexible piezoelectric generator include the multi-layer device design with contact windows and the simple fabrication process for the higher flexibility with the better energy harvesting efficiency. We have demonstrated the design effectiveness and the process simplicity of our skin- attachable flexible piezoelectric pulse wave energy harvester, composed of the sensitive P(VDF-TrFE) piezoelectric layer on the flexible polyimide support layer with windows. We experimentally characterize and demonstrate the energy harvesting capability of 0.2~1.0?W in the Human heart rate range on the skin contact area of 3.71cm2. Additional physiological and/or vital signal monitoring devices can be fabricated and integrated on the skin attachable flexible generator, covered by an insulation layer; thus demonstrating the potentials and advantages of the present device for such applications to the flexible multi-functional selfpowered artificial skins, capable to detect physiological and/or vital signals on Human skin using the energy harvested from arterial pulse waves.
A design and experimental verification methodology for an energy harvester skin structure
NASA Astrophysics Data System (ADS)
Lee, Soobum; Youn, Byeng D.
2011-05-01
This paper presents a design and experimental verification methodology for energy harvesting (EH) skin, which opens up a practical and compact piezoelectric energy harvesting concept. In the past, EH research has primarily focused on the design improvement of a cantilever-type EH device. However, such EH devices require additional space for proof mass and fixture and sometimes result in significant energy loss as the clamping condition becomes loose. Unlike the cantilever-type device, the proposed design is simply implemented by laminating a thin piezoelectric patch onto a vibrating structure. The design methodology proposed, which determines a highly efficient piezoelectric material distribution, is composed of two tasks: (i) topology optimization and (ii) shape optimization of the EH material. An outdoor condensing unit is chosen as a case study among many engineered systems with harmonic vibrating configuration. The proposed design methodology determined an optimal PZT material configuration on the outdoor unit skin structure. The designed EH skin was carefully prototyped to demonstrate that it can generate power up to 3.7 mW, which is sustainable for operating wireless sensor units for structural health monitoring and/or building automation.
Cooperative Energy Harvesting-Adaptive MAC Protocol for WBANs
Esteves, Volker; Antonopoulos, Angelos; Kartsakli, Elli; Puig-Vidal, Manel; Miribel-Català, Pere; Verikoukis, Christos
2015-01-01
In this paper, we introduce a cooperative medium access control (MAC) protocol, named cooperative energy harvesting (CEH)-MAC, that adapts its operation to the energy harvesting (EH) conditions in wireless body area networks (WBANs). In particular, the proposed protocol exploits the EH information in order to set an idle time that allows the relay nodes to charge their batteries and complete the cooperation phase successfully. Extensive simulations have shown that CEH-MAC significantly improves the network performance in terms of throughput, delay and energy efficiency compared to the cooperative operation of the baseline IEEE 802.15.6 standard. PMID:26029950
Frequency-dependent energy harvesting via magnetic shape memory alloys
NASA Astrophysics Data System (ADS)
Sayyaadi, Hassan; Askari Farsangi, Mohammad Amin
2015-11-01
This paper is focused on presenting an accurate framework to describe frequency-dependent energy harvesting via magnetic shape memory alloys (MSMAs). Modeling strategy incorporates the phenomenological constitutive model developed formerly together with the magnetic diffusion equation. A hyperbolic hardening function is employed to define reorientation-induced strain hardening in the material, and the diffusion equation is used to add dynamic effects to the model. The MSMA prismatic specimen is surrounded by a pickup coil, and the induced voltage during martensite-variant reorientation is investigated with the help of Faraday’s law of magnetic field induction. It has been shown that, in order to harvest the maximum RMS voltage in the MSMA-based energy harvester, an optimum value of bias magnetic field exists, which is the corresponding magnetic field for the start of pseudoelasticity behavior. In addition, to achieve a more compact energy harvester with higher energy density, a specimen with a lower aspect ratio can be chosen. As the main novelty of the paper, it is found that the dynamic effects play a major role in determining the harvested voltage and power, especially for high excitation frequency or specimen thickness.
An optimal stochastic control theory for distributed energy harvesting networks
NASA Astrophysics Data System (ADS)
Scruggs, J. T.
2009-03-01
A new approach, based on H2 optimal control theory, is presented for the design of feedback controllers for energy harvesting systems for maximal power generation. The theory applies to stochastically excited vibratory systems in broadband stationary response, and allows for harvested power to be explicitly optimized. It is applicable to both single-transducer systems as well as coupled networks of many transducers. The theory accounts for the influence of energy harvesting on the dynamics of the structure to which the transducers are attached. It also accounts for resistive and semiconductor dissipation in the power-electronic network interfacing the transducers with energy storage. Due to its predominance in the literature, a piezoelectric bimorph cantilever beam is used as the context for the theory, and simulation examples are used to illustrate various aspects of the optimal controllers.
Title of thesis: SCHEDULING IN ENERGY HARVESTING SYSTEMS WITH HYBRID ENERGY STORAGE
Ulukus, Sennur
ABSTRACT Title of thesis: SCHEDULING IN ENERGY HARVESTING SYSTEMS WITH HYBRID ENERGY STORAGE and Computer Engineering In wireless networks, efficient energy storage and utilization plays a vital role transmission with an energy harvesting trans- mitter which has hybrid energy storage with a perfect super
NASA Astrophysics Data System (ADS)
Yang, Zhengbao; Zhu, Yang; Zu, Jean
2015-02-01
Harvesting ambient vibration energy is a promising method for realizing self-powered autonomous operation for low-power electronic devices. Most energy harvesters developed to date employ bending-beam configurations and work around the resonant points. There are two critical problems that have hindered the widespread adoption of energy harvesters: insufficient power output and narrow working bandwidth. To overcome these problems, we proposed a novel energy harvester, called a high-efficiency compressive-mode piezoelectric energy harvester (HC-PEH). The HC-PEH delicately synthesizes the merits of the force amplification effect of the flexural motion and the dynamic properties of elastic beams, and thus is capable of high power output with wide working bandwidth. In this paper, theoretical and experimental studies were performed on the HC-PEH. Taking nonlinear stiffness, nonlinear damping, and nonlinear piezoelectricity into account, we developed an analytical model that provides comprehensive insight into the nonlinear mechanical and electrical behaviors of the system. The analytical results closely render the experimental data and demonstrate great performance enhancement. In the experiment, a maximum power output of 54.7 mW is generated at 26 Hz under an acceleration of 4.9 m s-2, which is over one order of magnitude higher than other state-of-the-art systems.
Finite element modeling of electrically rectified piezoelectric energy harvesters
NASA Astrophysics Data System (ADS)
Wu, P. H.; Shu, Y. C.
2015-09-01
Finite element models are developed for designing electrically rectified piezoelectric energy harvesters. They account for the consideration of common interface circuits such as the standard and parallel-/series-SSHI (synchronized switch harvesting on inductor) circuits, as well as complicated structural configurations such as arrays of piezoelectric oscillators. The idea is to replace the energy harvesting circuit by the proposed equivalent load impedance together with the capacitance of negative value. As a result, the proposed framework is capable of being implemented into conventional finite element solvers for direct system-level design without resorting to circuit simulators. The validation based on COMSOL simulations carried out for various interface circuits by the comparison with the standard modal analysis model. The framework is then applied to the investigation on how harvested power is reduced due to fabrication deviations in geometric and material properties of oscillators in an array system. Remarkably, it is found that for a standard array system with strong electromechanical coupling, the drop in peak power turns out to be insignificant if the optimal load is carefully chosen. The second application is to design broadband energy harvesting by developing array systems with suitable interface circuits. The result shows that significant broadband is observed for the parallel (series) connection of oscillators endowed with the parallel-SSHI (series-SSHI) circuit technique.
Simulation and testing of a micro electromagnetic energy harvester for self-powered system
NASA Astrophysics Data System (ADS)
Lei, Yiming; Wen, Zhiyu; Chen, Li
2014-03-01
This paper describes a low cost and efficient electromagnetic vibration energy harvester (EVEH) for a self-powered system. The EVEH consists of a resistant (copper) spring, a permanent magnet (NdFeB35) and a wire-wound copper coil. The copper spring was fabricated by the laser precision cutting technology. A numerical model was adopted to analyze magnetic field distribution of a rectangle permanent magnet. The finite element (FEM) soft ANSYS was used to simulate the mechanical properties of the system. The testing results show that the micro electromagnetic vibration energy harvester can generate the maximal power 205.38 ?W at a resonance frequency of 124.2 Hz with an acceleration of 0.5 g (g = 9.8 ms-2) across a load the 265 ? and a superior normalized power density (NPD) of 456.5 ?W cm-3 g-2. The magnetic field distribution of the permanent magnet was calculated to optimize geometric parameters of the coil. The proposed EVEH has a high efficiency with the lower cost.
An Inductorless Self-Controlled Rectifier for Piezoelectric Energy Harvesting.
Lu, Shaohua; Boussaid, Farid
2015-01-01
This paper presents a high-efficiency inductorless self-controlled rectifier for piezoelectric energy harvesting. High efficiency is achieved by discharging the piezoelectric device (PD) capacitance each time the current produced by the PD changes polarity. This is achieved automatically without the use of delay lines, thereby making the proposed circuit compatible with any type of PD. In addition, the proposed rectifier alleviates the need for an inductor, making it suitable for on-chip integration. Reported experimental results show that the proposed rectifier can harvest up to 3.9 times more energy than a full wave bridge rectifier. PMID:26610492
Exploiting Mobility for Quality-Maximized Data Collection in Energy Harvesting Sensor Networks
Liang, Weifa
are promising and very efficient. I. INTRODUCTION With the advance of energy harvesting technology, energy in energy harvesting sensor networks as sensors can get recharged by renewable energy. This creates a shiftExploiting Mobility for Quality-Maximized Data Collection in Energy Harvesting Sensor Networks
Wireless energy transmission to supplement energy harvesters in sensor network applications
Farinholt, Kevin M; Taylor, Stuart G; Park, Gyuhae; Farrar, Charles R
2010-01-01
In this paper we present a method for coupling wireless energy transmission with traditional energy harvesting techniques in order to power sensor nodes for structural health monitoring applications. The goal of this study is to develop a system that can be permanently embedded within civil structures without the need for on-board power sources. Wireless energy transmission is included to supplement energy harvesting techniques that rely on ambient or environmental, energy sources. This approach combines several transducer types that harvest ambient energy with wireless transmission sources, providing a robust solution that does not rely on a single energy source. Experimental results from laboratory and field experiments are presented to address duty cycle limitations of conventional energy harvesting techniques, and the advantages gained by incorporating a wireless energy transmission subsystem. Methods of increasing the efficiency, energy storage medium, target applications and the integrated use of energy harvesting sources with wireless energy transmission will be discussed.
Energy Harvesting Two-Way Communications with Limited Energy and Data Storage
Yener, Aylin
Energy Harvesting Two-Way Communications with Limited Energy and Data Storage Burak Varan Aylin, we study two-way communication scenarios with energy harvesting. In particular, we consider the two with finite batteries and finite data buffers. This entails iteratively solving an energy problem, which
Low frequency acoustic energy harvesting using PZT piezoelectric plates in a straight tube resonator
NASA Astrophysics Data System (ADS)
Li, Bin; You, Jeong Ho; Kim, Yong-Joe
2013-05-01
A novel and practical acoustic energy harvesting mechanism to harvest traveling sound at low audible frequency is introduced and studied both experimentally and numerically. The acoustic energy harvester in this study contains a quarter-wavelength straight tube resonator with lead zirconate titanate (PZT) piezoelectric cantilever plates placed inside the tube. When the tube resonator is excited by an incident sound at its acoustic resonance frequency, the amplified acoustic pressure inside the tube drives the vibration motions of piezoelectric plates, resulting in the generation of electricity. To increase the total voltage and power, multiple PZT plates were placed inside the tube. The number of PZT plates to maximize the voltage and power is limited due to the interruption of air particle motion by the plates. It has been found to be more beneficial to place the piezoelectric plates in the first half of the tube rather than along the entire tube. With an incident sound pressure level of 100 dB, an output voltage of 5.089 V was measured. The output voltage increases linearly with the incident sound pressure. With an incident sound pressure of 110 dB, an output voltage of 15.689 V and a power of 12.697 mW were obtained. The corresponding areal and volume power densities are 0.635 mW cm-2 and 15.115 ?W cm-3, respectively.
NASA Astrophysics Data System (ADS)
Shahab, S.; Erturk, A.
2015-04-01
In this work, Macro-Fiber Composite (MFC)-based piezoelectric structures are employed for underwater mechanical base excitation (vibration energy harvesting) and electrical biomimetic actuation in bending operation at low frequencies. The MFC technology (fiber-based piezoelectric composites with interdigitated electrodes) exploits the effective 33-mode of piezoelectricity and strikes a balance between structural deformation and force levels for actuation to use in underwater locomotion, in addition to offering high power density for energy harvesting to enable battery-less underwater sensors. Following in-air electroelastic composite model development, it is aimed to establish semianalytical models that can predict the underwater dynamics of thin MFC cantilevers for different length-to-width aspect ratios. In-air analytical electroelastic dynamics of MFCs is therefore coupled with added mass and nonlinear hydrodynamic damping effects of fluid to describe the underwater electrohydroelastic dynamics in harvesting and actuation. To this end, passive plates of different aspect ratios are tested to extract and explore the repeatability of the inertia and drag coefficients in Morison's equation. The focus is placed on the first two bending modes in this semianalytical approach. Additionally, nonlinear dependence of the output power density to aspect ratio is characterized theoretically and experimentally in the underwater base excitation problem.
NASA Astrophysics Data System (ADS)
Zalesskaya, G. A.; Yakovlev, D. L.; Sambor, E. G.
2000-08-01
Efficiency of vibrational energy transfer (VET) in vibrational quasicontinuum of triplet states was estimated from the dependence of time-resolved delayed fluorescence of benzophenone and anthraquinone on bath gas pressure. The negative temperature dependence for vibration-vibration (V-V) and positive for vibration-translation (V-T) energy transfers from benzophenone and anthraquinone to bath gases (C 2H 4, SF 6, CCl 4, C 5H 12) were obtained between 373 and 553 K. Polarizability and dipole moment of colliding molecules seem to affect the efficiency of V-V relaxation. These data reflect the dominance of long-range attractive interactions in V-V energy transfer and short-range repulsive interactions in V-T energy transfer.
Energy harvesting from electric power lines employing the Halbach arrays.
He, Wei; Li, Ping; Wen, Yumei; Zhang, Jitao; Lu, Caijiang; Yang, Aichao
2013-10-01
This paper proposes non-invasive energy harvesters to scavenge alternating magnetic field energy from electric power lines. The core body of a non-invasive energy harvester is a linear Halbach array, which is mounted on the free end of a piezoelectric cantilever beam. The Halbach array augments the magnetic flux density on the side of the array where the power line is placed and significantly lowers the magnetic field on the other side. Consequently, the magnetic coupling strength is enhanced and more alternating magnetic field energy from the current-carrying power line is converted into electrical energy. An analytical model is developed and the theoretical results verify the experimental results. A power of 566 ?W across a 196 k? resistor is generated from a single wire, and a power of 897 ?W across a 212 k? resistor is produced from a two-wire power cord carrying opposite currents at 10 A. The harvesters employing Halbach arrays for a single wire and a two-wire power cord, respectively, exhibit 3.9 and 3.2 times higher power densities than those of the harvesters employing conventional layouts of magnets. The proposed devices with strong response to the alternating currents are promising to be applied to electricity end-use environment in electric power systems. PMID:24182155
Production, Delivery and Application of Vibration Energy in Healthcare
NASA Astrophysics Data System (ADS)
Abundo, Paolo; Trombetta, Chiara; Foti, Calogero; Rosato, Nicola
2011-02-01
In Rehabilitation Medicine therapeutic application of vibration energy in specific clinical treatments and in sport rehabilitation is being affirmed more and more.Vibration exposure can have positive or negative effects on the human body depending on the features and time of the characterizing wave. The human body is constantly subjected to different kinds of vibrations, inducing bones and muscles to actively modify their structure and metabolism in order to fulfill the required functions. Like every other machine, the body supports only certain vibration energy levels over which long term impairments can be recognized. As shown in literature anyway, short periods of vibration exposure and specific frequency values can determine positive adjustments.
Methods of performing downhole operations using orbital vibrator energy sources
Cole, Jack H.; Weinberg, David M.; Wilson, Dennis R.
2004-02-17
Methods of performing down hole operations in a wellbore. A vibrational source is positioned within a tubular member such that an annulus is formed between the vibrational source and an interior surface of the tubular member. A fluid medium, such as high bulk modulus drilling mud, is disposed within the annulus. The vibrational source forms a fluid coupling with the tubular member through the fluid medium to transfer vibrational energy to the tubular member. The vibrational energy may be used, for example, to free a stuck tubular, consolidate a cement slurry and/or detect voids within a cement slurry prior to the curing thereof.
Feasibility of energy harvesting techniques for wearable medical devices.
Voss, Thaddaeus J; Subbian, Vignesh; Beyette, Fred R
2014-08-01
Wearable devices are arguably one of the most rapidly growing technologies in the computing and health care industry. These systems provide improved means of monitoring health status of humans in real-time. In order to cope with continuous sensing and transmission of biological and health status data, it is desirable to move towards energy autonomous systems that can charge batteries using passive, ambient energy. This not only ensures uninterrupted data capturing, but could also eliminate the need to frequently remove, replace, and recharge batteries. To this end, energy harvesting is a promising area that can lead to extremely power-efficient portable medical devices. This paper presents an experimental prototype to study the feasibility of harvesting two energy sources, solar and thermoelectric energy, in the context of wearable devices. Preliminary results show that such devices can be powered by transducing ambient energy that constantly surrounds us. PMID:25570037
The Use of A Mobile Sink for Quality Data Collection in Energy Harvesting Sensor Networks
Liang, Weifa
The Use of A Mobile Sink for Quality Data Collection in Energy Harvesting Sensor Networks Xiaojiang collection in an energy harvesting sensor network where sensors are deployed along a given path and a mobile are powered by renew- able energy sources, the time-varying characteristics of energy harvesting poses great
Resonant vibrational energy transfer in ice Ih
Shi, L.; Li, F.; Skinner, J. L.
2014-06-28
Fascinating anisotropy decay experiments have recently been performed on H{sub 2}O ice Ih by Timmer and Bakker [R. L. A. Timmer, and H. J. Bakker, J. Phys. Chem. A 114, 4148 (2010)]. The very fast decay (on the order of 100 fs) is indicative of resonant energy transfer between OH stretches on different molecules. Isotope dilution experiments with deuterium show a dramatic dependence on the hydrogen mole fraction, which confirms the energy transfer picture. Timmer and Bakker have interpreted the experiments with a Förster incoherent hopping model, finding that energy transfer within the first solvation shell dominates the relaxation process. We have developed a microscopic theory of vibrational spectroscopy of water and ice, and herein we use this theory to calculate the anisotropy decay in ice as a function of hydrogen mole fraction. We obtain very good agreement with experiment. Interpretation of our results shows that four nearest-neighbor acceptors dominate the energy transfer, and that while the incoherent hopping picture is qualitatively correct, vibrational energy transport is partially coherent on the relevant timescale.
Amplified energy harvester from footsteps: design, modeling, and experimental analysis
NASA Astrophysics Data System (ADS)
Wang, Ya; Chen, Wusi; Guzman, Plinio; Zuo, Lei
2014-04-01
This paper presents the design, modeling and experimental analysis of an amplified footstep energy harvester. With the unique design of amplified piezoelectric stack harvester the kinetic energy generated by footsteps can be effectively captured and converted into usable DC power that could potentially be used to power many electric devices, such as smart phones, sensors, monitoring cameras, etc. This doormat-like energy harvester can be used in crowded places such as train stations, malls, concerts, airport escalator/elevator/stairs entrances, or anywhere large group of people walk. The harvested energy provides an alternative renewable green power to replace power requirement from grids, which run on highly polluting and global-warming-inducing fossil fuels. In this paper, two modeling approaches are compared to calculate power output. The first method is derived from the single degree of freedom (SDOF) constitutive equations, and then a correction factor is applied onto the resulting electromechanically coupled equations of motion. The second approach is to derive the coupled equations of motion with Hamilton's principle and the constitutive equations, and then formulate it with the finite element method (FEM). Experimental testing results are presented to validate modeling approaches. Simulation results from both approaches agree very well with experimental results where percentage errors are 2.09% for FEM and 4.31% for SDOF.
Grafting Energy-Harvesting Leaves onto the Sensornet Tree
Cafarella, Michael J.
the problem of augmenting battery-powered sen- sornet trees with energy-harvesting leaf nodes. Our results show that leaf nodes that are smaller in size than today's typi- cal battery-powered sensors can. IPSN'12, April 1620, 2012, Beijing, China. Copyright 2012 ACM 978-1-4503-1227-1/12/04 ...$5.00. 1
Energy harvesting for the implantable biomedical devices: issues and challenges
2014-01-01
The development of implanted devices is essential because of their direct effect on the lives and safety of humanity. This paper presents the current issues and challenges related to all methods used to harvest energy for implantable biomedical devices. The advantages, disadvantages, and future trends of each method are discussed. The concept of harvesting energy from environmental sources and human body motion for implantable devices has gained a new relevance. In this review, the harvesting kinetic, electromagnetic, thermal and infrared radiant energies are discussed. Current issues and challenges related to the typical applications of these methods for energy harvesting are illustrated. Suggestions and discussion of the progress of research on implantable devices are also provided. This review is expected to increase research efforts to develop the battery-less implantable devices with reduced over hole size, low power, high efficiency, high data rate, and improved reliability and feasibility. Based on current literature, we believe that the inductive coupling link is the suitable method to be used to power the battery-less devices. Therefore, in this study, the power efficiency of the inductive coupling method is validated by MATLAB based on suggested values. By further researching and improvements, in the future the implantable and portable medical devices are expected to be free of batteries. PMID:24950601
Energy harvesting for the implantable biomedical devices: issues and challenges.
Hannan, Mahammad A; Mutashar, Saad; Samad, Salina A; Hussain, Aini
2014-01-01
The development of implanted devices is essential because of their direct effect on the lives and safety of humanity. This paper presents the current issues and challenges related to all methods used to harvest energy for implantable biomedical devices. The advantages, disadvantages, and future trends of each method are discussed. The concept of harvesting energy from environmental sources and human body motion for implantable devices has gained a new relevance. In this review, the harvesting kinetic, electromagnetic, thermal and infrared radiant energies are discussed. Current issues and challenges related to the typical applications of these methods for energy harvesting are illustrated. Suggestions and discussion of the progress of research on implantable devices are also provided. This review is expected to increase research efforts to develop the battery-less implantable devices with reduced over hole size, low power, high efficiency, high data rate, and improved reliability and feasibility. Based on current literature, we believe that the inductive coupling link is the suitable method to be used to power the battery-less devices. Therefore, in this study, the power efficiency of the inductive coupling method is validated by MATLAB based on suggested values. By further researching and improvements, in the future the implantable and portable medical devices are expected to be free of batteries. PMID:24950601
Online Fault Detection and Tolerance for Photovoltaic Energy Harvesting Systems
Pedram, Massoud
Online Fault Detection and Tolerance for Photovoltaic Energy Harvesting Systems Xue Lin 1 , Yanzhi (PV systems) are subject to PV cell faults, which decrease the efficiency of PV systems and even shorten the PV system lifespan. Manual PV cell fault detection and elimination are expensive and nearly
Myocardial Cell Pattern on Piezoelectric Nanofiber Mats for Energy Harvesting
NASA Astrophysics Data System (ADS)
Liu, X.; Wang, X.; Zhao, H.; Du, Y.
2014-11-01
The paper presents in vitro contractile myocardial cell pattern on piezoelectric nanofiber mats with applications in energy harvesting. The cell-based energy harvester consists of myocardial cell sheet and a PDMS substrate with a PVDF nanofiber mat on. Experimentally, cultured on specifically distributed nanofiber mats, neonatal rat ventricular cardiomyocytes are characterized with the related morphology and contraction. Previously, we have come up with the concept of energy harvesting from heart beating using piezoelectric material. A bio-hybrid energy harvester combined living cardiomyocytes, PDMS polymer substrate and piezoelectric PVDF film with the electrical output of peak current 87.5nA and peak voltage 92.3mV. However, the thickness of the cardiomyocyte cultured on a two-dimensional substrate is much less than that of the piezoelectric film. The Micro Contact Printing (?CP) method used in cell pattern on the PDMS thin film has tough requirement for the film surface. As such, in this paper we fabricated nanofiber-constructed PDMS thin film to realize cell pattern due to PVDF nanofibers with better piezoelectricity and microstructures of nanofiber mats guiding cell distribution. Living cardiomyocytes patterned on those distributed piezoelectric nanofibers with the result of the same distribution as the nanofiber pattern.
High-Damping Energy-Harvesting Electrostatic CMOS Charger
Rincon-Mora, Gabriel A.
adjusting the electrical damping force in the transducer is therefore as important as lowering power losses abate the sacrifice, but only to the extent transducer and circuit efficiencies allow. Optimally increases this force, which is what the energy-harvesting 0.35-µm CMOS charger proposed achieves with a 10-n
Nonlinear beam-based vibration energy harvesters and load cells
Kluger, Jocelyn Maxine
2014-01-01
This thesis studies a novel nonlinear spring mechanism that is comprised of a cantilever wrapping around a curved surface as it deflects. Static force versus displacement tests and dynamic "initial displacement" tests ...
Energy Harvesting Systems and Methods of Assembling Same
NASA Technical Reports Server (NTRS)
Cepeda-Rizo, Juan (Inventor); Ganapathi, Gani B. (Inventor)
2013-01-01
A method of assembling an energy harvesting system is provided. The method includes coupling at least one energy storage device in flow communication with at least one apparatus that is configured to generate thermal energy and to transfer the thermal energy into at least one fluid stream. The energy storage device is configured to store the fluid stream. Moreover, the method includes coupling at least one fluid transfer device downstream from the energy storage device. The fluid transfer device receives the fluid stream from the energy storage device. A bladeless turbine is coupled in flow communication with the fluid transfer device, wherein the bladeless turbine receives the fluid stream to generate power.
Magnetic Force Driven Nanogenerators as a Noncontact Energy Harvester and Sensor
Wang, Zhong L.
Supporting Information ABSTRACT: Nanogenerator has been a very important energy harvesting technology throughMagnetic Force Driven Nanogenerators as a Noncontact Energy Harvester and Sensor Nuanyang Cui and Nanotechnology, Lanzhou University, Lanzhou 730000, China Beijing National Laboratory for Molecular Sciences
Power Management in Cluster-Based Energy-Harvesting Sensor Networks through
Aydin, Hakan
harvesting technology to charge the storage units that power the wireless sensor nodes offers multiple, there has been a growing interest in using energy harvesting solutions in WSNs. Using environmental energy
Fluttering energy harvesters in the wind: A review
NASA Astrophysics Data System (ADS)
McCarthy, J. M.; Watkins, S.; Deivasigamani, A.; John, S. J.
2016-01-01
The growing area of harvesting energy by aerodynamically induced flutter in a fluid stream is reviewed. Numerous approaches were found to understand, demonstrate and [sometimes] optimise harvester performance based on Movement-Induced or Extraneously Induced Excitation. Almost all research was conducted in smooth, unidirectional flow domains; either experimental or computational. The power outputs were found to be very low when compared to conventional wind turbines, but potential advantages could be lower noise levels. A consideration of the likely outdoor environment for fluttering harvesters revealed that the flow would be highly turbulent and having a mean flow angle in the horizontal plane that could approach a harvester from any direction. Whilst some multiple harvester systems in smooth, well-aligned flow found enhanced efficiency (due to beneficial wake interaction) this would require an invariant flow approach angle. It was concluded that further work needs to be performed to find a universally accepted metric for efficiency and to understand the effects of the realities of the outdoors, including the highly variable and turbulent flow conditions likely to be experienced.
Energy harvesting measurements from stall flutter limit cycle oscillations
NASA Astrophysics Data System (ADS)
Chen, Jasper; Dhanushkodi, Adit; Lee, Christopher L.
2014-04-01
Results from experiments using a two-degree-of-freedom airfoil system are presented. Air speeds of the airfoil are determined at which dynamic flutter can be initiated and where limit cycle oscillations (LCO) can be excited by initial (pitch or plunge) displacements. LCO's with large pitch angle displacements attributed to stall flutter behavior are measured. The LCO oscillations are converted into electric power by an electromagnetic-inductor device. The energy harvester consists of three magnets in which one magnet floats between two fixed magnets. The force-displacement relationship of the harvester is best described by a fifth-order polynomial. The integration of the harvester into the airfoil system introduces nonlinear stiffness into the vertical (plunge) direction. When the LCO has been initiated, displacement amplitudes and resulting power generation are measured.
Thermal modeling and optimization of a thermally matched energy harvester
NASA Astrophysics Data System (ADS)
Boughaleb, J.; Arnaud, A.; Cottinet, P. J.; Monfray, S.; Gelenne, P.; Kermel, P.; Quenard, S.; Boeuf, F.; Guyomar, D.; Skotnicki, T.
2015-08-01
The interest in energy harvesting devices has grown with the development of wireless sensors requiring small amounts of energy to function. The present article addresses the thermal investigation of a coupled piezoelectric and bimetal-based heat engine. The thermal energy harvester in question converts low-grade heat flows into electrical charges by achieving a two-step conversion mechanism for which the key point is the ability to maintain a significant thermal gradient without any heat sink. Many studies have previously focused on the electrical properties of this innovative device for energy harvesting but until now, no thermal modeling has been able to describe the device specificities or improve its thermal performances. The research reported in this paper focuses on the modeling of the harvester using an equivalent electrical circuit approach. It is shown that the knowledge of the thermal properties inside the device and a good comprehension of its heat exchange with the surrounding play a key role in the optimization procedure. To validate the thermal modeling, finite element analyses as well as experimental measurements on a hot plate were carried out and the techniques were compared. The proposed model provided a practical guideline for improving the generator design to obtain a thermally matched energy harvester that can function over a wide range of hot source temperatures for the same bimetal. A direct application of this study has been implemented on scaled structures to maintain an important temperature difference between the cold surface and the hot reservoir. Using the equations of the thermal model, predictions of the thermal properties were evaluated depending on the scaling factor and solutions for future thermal improvements are presented.
Statistical energy analysis of nonlinear vibrating systems.
Spelman, G M; Langley, R S
2015-09-28
Nonlinearities in practical systems can arise in contacts between components, possibly from friction or impacts. However, it is also known that quadratic and cubic nonlinearity can occur in the stiffness of structural elements undergoing large amplitude vibration, without the need for local contacts. Nonlinearity due purely to large amplitude vibration can then result in significant energy being found in frequency bands other than those being driven by external forces. To analyse this phenomenon, a method is developed here in which the response of the structure in the frequency domain is divided into frequency bands, and the energy flow between the frequency bands is calculated. The frequency bands are assigned an energy variable to describe the mean response and the nonlinear coupling between bands is described in terms of weighted summations of the convolutions of linear modal transfer functions. This represents a nonlinear extension to an established linear theory known as statistical energy analysis (SEA). The nonlinear extension to SEA theory is presented for the case of a plate structure with quadratic and cubic nonlinearity. PMID:26303923
Lallart, Mickaeel; Cottinet, Pierre-Jean; Lebrun, Laurent; Guiffard, Benoit; Guyomar, Daniel
2010-08-15
Recent trends in energy conversion mechanisms have demonstrated the abilities of electrostrictive polymers for converting mechanical vibrations into electricity. In particular, such materials present advantageous features such as high productivity, high flexibility, and processability. Hence, the application of these materials for energy harvesting purposes has been of significant interest over the last few years. The purpose of this paper consists in evaluating the energy scavenging abilities of electrostrictive terpolymer composite filled with 1 vol % carbon black poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene). For fair comparison, a new figure of merit taking into account the intrinsic parameters of the material is introduced. This figure of merit equals the squared product of the electric field-related electrostrictive coefficient by the Young modulus, divided by the permittivity, relating the electric energy density per cycle per squared strain magnitude and squared bias electric field. Based on this criterion, it is demonstrated that the carbon-filled terpolymer outperforms other investigated compositions, exhibiting a figure of merit as high as 30 mJ cm{sup -3} (m/m){sup -2} (V/{mu}m){sup -2} cycle{sup -1}, which is 2000 times higher than pure polyurethane. In addition, the comparison of the figure of merit with experimental maximal harvested powers shows that such a criterion allows a very accurate prediction of the energy scavenging performance of electrostrictive composites.
The Binary Energy Harvesting Channel with a Unit-Sized Battery
Ulukus, Sennur
1 The Binary Energy Harvesting Channel with a Unit-Sized Battery Kaya Tutuncuoglu1 , Omur Ozel2 a binary energy harvesting communication channel with a finite-sized battery at the transmitter by an external energy harvesting process, the size of the battery, and the previous channel inputs. We consider
Demo: Organic Solar Cell-equipped Energy Harvesting Active Networked Tag (EnHANT) Prototypes
Carloni, Luca
Demo: Organic Solar Cell-equipped Energy Harvesting Active Networked Tag (EnHANT) Prototypes Gerald their communications and networking parameters to the available environmental energy harvested by the organic solar harvesting, organic solar cells, ultra-low-power com- munications, ultra-wideband impulse radio, energy
POWER EVALUATION FOR FLUTTER-BASED ELCTROMAGNETIC ENERGY HARVESTER USING CFD SIMULATIONS
Stanford University
POWER EVALUATION FOR FLUTTER-BASED ELCTROMAGNETIC ENERGY HARVESTER USING CFD SIMULATIONS J. Park 1 from the flutter based energy harvester are challenging. VXflow, a CFD code based on the vortex. KEYWORDS Flutter, CFD simulation, aerodynamic instability, energy harvesting, electromagnetic. INTRODUCTION
Upper bounds for energy harvesting in the region of the human head.
Goll, Erich; Zenner, Hans-Peter; Dalhoff, Ernst
2011-11-01
This paper investigates different approaches for supplying power to implantable hearing systems via energy harvesting. Because of the specific nature of the problem, only energy harvesting in the region of the human head is considered. Upper bounds as well as more conservative estimations for harvesting mechanical, thermal, and electromagnetic energy are presented and discussed. PMID:21813361
Kissock, Kelly
Industrial Solid-State Energy Harvesting: Mechanisms and Examples Matthew Kocoloski, Carnegie the potential for solid-state energy harvesting in industrial applications. In contrast to traditional heat in an industrial application. The example considers energy harvesting from a furnace at a glass manufacturing
Energy harvesting concepts for small electric unmanned systems
NASA Astrophysics Data System (ADS)
Qidwai, Muhammad A.; Thomas, James P.; Kellogg, James C.; Baucom, Jared N.
2004-07-01
In this study, we identify and survey energy harvesting technologies for small electrically powered unmanned systems designed for long-term (>1 day) time-on-station missions. An environmental energy harvesting scheme will provide long-term, energy additions to the on-board energy source. We have identified four technologies that cover a broad array of available energy sources: solar, kinetic (wind) flow, autophagous structure-power (both combustible and metal air-battery systems) and electromagnetic (EM) energy scavenging. We present existing conceptual designs, critical system components, performance, constraints and state-of-readiness for each technology. We have concluded that the solar and autophagous technologies are relatively matured for small-scale applications and are capable of moderate power output levels (>1 W). We have identified key components and possible multifunctionalities in each technology. The kinetic flow and EM energy scavenging technologies will require more in-depth study before they can be considered for implementation. We have also realized that all of the harvesting systems require design and integration of various electrical, mechanical and chemical components, which will require modeling and optimization using hybrid mechatronics-circuit simulation tools. This study provides a starting point for detailed investigation into the proposed technologies for unmanned system applications under current development.
Near-field thermodynamics: Useful work, efficiency, and energy harvesting
Latella, Ivan Pérez-Madrid, Agustín; Lapas, Luciano C.; Miguel Rubi, J.
2014-03-28
We show that the maximum work that can be obtained from the thermal radiation emitted between two planar sources in the near-field regime is much larger than that corresponding to the blackbody limit. This quantity, as well as an upper bound, for the efficiency of the process is computed from the formulation of thermodynamics in the near-field regime. The case when the difference of temperatures of the hot source and the environment is small, relevant for energy harvesting, is studied in detail. We also show that thermal radiation energy conversion can be more efficient in the near-field regime. These results open new possibilities for the design of energy converters that can be used to harvest energy from sources of moderate temperature at the nanoscale.
Energy harvesting with piezoelectric circular membrane under pressure loading
NASA Astrophysics Data System (ADS)
Mo, Changki; Davidson, Joseph; Clark, William W.
2014-04-01
This paper presents a comprehensive theoretical model for predicting the energy generating performance of an energy harvesting device that uses a piezoelectric circular membrane subject to pressure fluctuation. PVDF (polyvinylidene fluoride) film is adopted for the membrane. In order to predict the power generating performance due to stretching and bending of the membrane, the total stress on the membrane, rather than the stress at the center point of the circular membrane, is determined using the energy method. Analytical results indicate that the theoretically predicted generated power of the device under normal blood pressure variation is close to experimental results available in the literature. This comprehensive model provides a useful design tool during parameter optimization for energy harvesters that use piezoelectric circular membranes for a pressure fluctuating system.
Nonlinear and multiscale dynamics of smart materials in energy harvesting
NASA Astrophysics Data System (ADS)
Litak, G.; Manoach, E.; Halvorsen, E.
2015-11-01
This special issue is a result of discussions performed during a workshop (with the same name) held in Lublin, February 2014. This meeting served as the seed to invite several experts in the field to present contributions for this Special Topics issue which reflect the present state of the art for research and development of smart materials and their possible applications for energy control and energy harvesting.
Light-harvesting materials: Soft support for energy conversion
Stolley, Ryan M.; Helm, Monte L.
2014-11-10
To convert solar energy into viable fuel sources, coupling light-harvesting materials to catalysts is a critical challenge. Now, coupling between an organic supramolecular hydrogel and a non precious metal catalyst has been demonstrated to be effective for photocatalytic H2 production. Ryan M. Stolley and Monte L. Helm are at Pacific Northwest National Laboratory (PNNL), Richland, WA, USA 99352. PNNL is operated by Battelle for the US Department of Energy. e-mail: Monte.Helm@pnnl.gov
A miniature airflow energy harvester from piezoelectric materials
NASA Astrophysics Data System (ADS)
Sun, H.; Zhu, D.; White, N. M.; Beeby, S. P.
2013-12-01
This paper describes design, simulation, fabrication, and testing of a miniature wind energy harvester based on a flapping cantilevered piezoelectric beam. The wind generator is based on oscillations of a cantilever that faces the direction of the airflow. The oscillation is amplified by interactions between an aerofoil attached on the cantilever and a bluff body placed in front of the aerofoil. A piezoelectric transducer with screen printed PZT materials is used to extract electrical energy. To achieve the optimum design of the harvester, both computational simulations and experiments have been carried out to investigate the structure. A prototype of the wind harvester, with the volume of 37.5 cm3 in total, was fabricated by thick-film screen printing technique. Wind tunnel test results are presented to determine the optimum structure and to characterize the performance of the harvester. The optimized device finally achieved a working wind speed range from 1.5 m/s to 8 m/s. The power output was ranging from 0.1 to 0.86 ?W and the open-circuit output voltage was from 0.5 V to 1.32 V.
Bioinspired model of mechanical energy harvesting based on flexoelectric membranes.
Rey, Alejandro D; Servio, P; Herrera-Valencia, E E
2013-02-01
Membrane flexoelectricity is an electromechanical coupling process that describes membrane electrical polarization due to bending and membrane bending under electric fields. In this paper we propose, formulate, and characterize a mechanical energy harvesting system consisting of a deformable soft flexoelectric thin membrane subjected to harmonic forcing from contacting bulk fluids. The key elements of the energy harvester are formulated and characterized, including (i) the mechanical-to-electrical energy conversion efficiency, (ii) the electromechanical shape equation connecting fluid forces with membrane curvature and electric displacement, and (iii) the electric power generation and efficiency. The energy conversion efficiency is cast as the ratio of flexoelectric coupling to the product of electric and bending elasticity. The device is described by a second-order curvature dynamics coupled to the electric displacement equation and as such results in mechanical power absorption with a resonant peak whose amplitude decreases with bending viscosity. The electric power generation is proportional to the conversion factor and the power efficiency decreases with frequency. Under high bending viscosity, the power efficiency increases with the conversion factor and under low viscosities it decreases with the conversion factor. The theoretical results presented contribute to the ongoing experimental efforts to develop mechanical energy harvesting from fluid flow energy through solid-fluid interactions and electromechanical transduction. PMID:23496533
Bioinspired model of mechanical energy harvesting based on flexoelectric membranes
NASA Astrophysics Data System (ADS)
Rey, Alejandro D.; Servio, P.; Herrera-Valencia, E. E.
2013-02-01
Membrane flexoelectricity is an electromechanical coupling process that describes membrane electrical polarization due to bending and membrane bending under electric fields. In this paper we propose, formulate, and characterize a mechanical energy harvesting system consisting of a deformable soft flexoelectric thin membrane subjected to harmonic forcing from contacting bulk fluids. The key elements of the energy harvester are formulated and characterized, including (i) the mechanical-to-electrical energy conversion efficiency, (ii) the electromechanical shape equation connecting fluid forces with membrane curvature and electric displacement, and (iii) the electric power generation and efficiency. The energy conversion efficiency is cast as the ratio of flexoelectric coupling to the product of electric and bending elasticity. The device is described by a second-order curvature dynamics coupled to the electric displacement equation and as such results in mechanical power absorption with a resonant peak whose amplitude decreases with bending viscosity. The electric power generation is proportional to the conversion factor and the power efficiency decreases with frequency. Under high bending viscosity, the power efficiency increases with the conversion factor and under low viscosities it decreases with the conversion factor. The theoretical results presented contribute to the ongoing experimental efforts to develop mechanical energy harvesting from fluid flow energy through solid-fluid interactions and electromechanical transduction.
Structural Optimization of Triboelectric Nanogenerator for Harvesting Water Wave Energy.
Jiang, Tao; Zhang, Li Min; Chen, Xiangyu; Han, Chang Bao; Tang, Wei; Zhang, Chi; Xu, Liang; Wang, Zhong Lin
2015-12-22
Ocean waves are one of the most abundant energy sources on earth, but harvesting such energy is rather challenging due to various limitations of current technologies. Recently, networks formed by triboelectric nanogenerator (TENG) have been proposed as a promising technology for harvesting water wave energy. In this work, a basic unit for the TENG network was studied and optimized, which has a box structure composed of walls made of TENG composed of a wavy-structured Cu-Kapton-Cu film and two FEP thin films, with a metal ball enclosed inside. By combination of the theoretical calculations and experimental studies, the output performances of the TENG unit were investigated for various structural parameters, such as the size, mass, or number of the metal balls. From the viewpoint of theory, the output characteristics of TENG during its collision with the ball were numerically calculated by the finite element method and interpolation method, and there exists an optimum ball size or mass to reach maximized output power and electric energy. Moreover, the theoretical results were well verified by the experimental tests. The present work could provide guidance for structural optimization of wavy-structured TENGs for effectively harvesting water wave energy toward the dream of large-scale blue energy. PMID:26567754
Investigations of a nonlinear energy harvester with a bistable potential well
NASA Astrophysics Data System (ADS)
Mann, B. P.; Owens, B. A.
2010-04-01
This paper investigates a nonlinear energy harvester that uses magnetic interactions to create an inertial generator with a bistable potential well. The motivating hypothesis for this work was that nonlinear behavior could be used to improve the performance of an energy harvester by broadening its frequency response. Theoretical investigations study the harvester's response when directly powering an electrical load. Both theoretical and experimental tests show that the potential well escape phenomenon can be used to broaden the frequency response of an energy harvester.
Structures, systems and methods for harvesting energy from electromagnetic radiation
Novack, Steven D. (Idaho Falls, ID); Kotter, Dale K. (Shelley, ID); Pinhero, Patrick J. (Columbia, MO)
2011-12-06
Methods, devices and systems for harvesting energy from electromagnetic radiation are provided including harvesting energy from electromagnetic radiation. In one embodiment, a device includes a substrate and one or more resonance elements disposed in or on the substrate. The resonance elements are configured to have a resonant frequency, for example, in at least one of the infrared, near-infrared and visible light spectra. A layer of conductive material may be disposed over a portion of the substrate to form a ground plane. An optical resonance gap or stand-off layer may be formed between the resonance elements and the ground plane. The optical resonance gap extends a distance between the resonance elements and the layer of conductive material approximately one-quarter wavelength of a wavelength of the at least one resonance element's resonant frequency. At least one energy transfer element may be associated with the at least one resonance element.
A Belleville-spring-based electromagnetic energy harvester
NASA Astrophysics Data System (ADS)
Castagnetti, Davide
2015-09-01
Energy harvesting from kinetic ambient energy is particularly effective to power autonomous sensors. This work proposes an innovative energy converter based on two counteracting Belleville springs and exploiting their peculiarity, for a height to thickness ratio equal to 1.414, of nearly zero stiffness over a wide deflection range. After analytical and numerical modelling a prototype is developed and experimentally investigated. The sub-optimal geometry of the commercial springs used in the prototype, together with a non-ideal response, makes the operating frequency for the prototype higher than in analytical and numerical predictions. Nevertheless, the harvester exhibits a significantly large bandwidth, together with a high output power, compared to similar solutions in the literature, for all the examined configurations and input excitations.
Energy harvesting efficiency of piezoelectric flags in axial flows
Michelin, Sebastien
2012-01-01
Self-sustained oscillations resulting from fluid-solid instabilities, such as the flutter of a flexible flag in axial flow, can be used to harvest energy if one is able to convert the solid energy into electricity. Here, this is achieved using piezoelectric patches attached to the surface of the flag that convert the solid deformation into an electric current powering purely resistive output circuits. Nonlinear numerical simulations in the slender-body limit, based on an explicit description of the coupling between the fluid-solid and electric systems, are used to determine the harvesting efficiency of the system, namely the fraction of the flow kinetic energy flux effectively used to power the output circuit, and its evolution with the system's parameters. The role of the tuning between the characteristic frequencies of the fluid-solid and electric systems is emphasized, as well as the critical impact of the piezoelectric coupling intensity. High fluid loading, classically associated with destabilization by ...
Parametric energy conversion of thermoacoustic vibrations
NASA Astrophysics Data System (ADS)
Guthy, C.; Van Neste, C. W.; Mitra, S.; Bhattacharjee, S.; Thundat, T.
2012-05-01
We demonstrate a parametric energy conversion method of thermoacoustic (TA) vibrations into electrical oscillations of a LC circuit. The inductance modulation necessary to excite the parametric oscillations is achieved by varying the air gap between two halves of a ferrite E-core coil. As a proof-of-concept, the parametric converter was attached to a Sondhauss tube that converts the heat into acoustic vibrations. The maximum total acoustic power output of this thermoacoustic engine was ˜5.3 mW. A flexible metallic membrane capping the Sondhauss tube connected to the moving half E-core served as a mechanical oscillator. The resonance frequency of the membrane was matched with the operating frequency (130 Hz) of the Sondhauss tube for resonant energy extraction. We have characterized the power output of the complete system as a function of electrical load. The maximum electrical power of 2.3 mW produced by the system corresponds to an acoustic-to-electric conversion efficiency of 44%.
Optimal Energy Transfer in Light-Harvesting Systems.
Chen, Lipeng; Shenai, Prathamesh; Zheng, Fulu; Somoza, Alejandro; Zhao, Yang
2015-01-01
Photosynthesis is one of the most essential biological processes in which specialized pigment-protein complexes absorb solar photons, and with a remarkably high efficiency, guide the photo-induced excitation energy toward the reaction center to subsequently trigger its conversion to chemical energy. In this work, we review the principles of optimal energy transfer in various natural and artificial light harvesting systems. We begin by presenting the guiding principles for optimizing the energy transfer efficiency in systems connected to dissipative environments, with particular attention paid to the potential role of quantum coherence in light harvesting systems. We will comment briefly on photo-protective mechanisms in natural systems that ensure optimal functionality under varying ambient conditions. For completeness, we will also present an overview of the charge separation and electron transfer pathways in reaction centers. Finally, recent theoretical and experimental progress on excitation energy transfer, charge separation, and charge transport in artificial light harvesting systems is delineated, with organic solar cells taken as prime examples. PMID:26307957
Harvesting the Sun's Energy with Antennas
INL
2009-09-01
Researchers at Idaho National Laboratory, along with partners at Microcontinuum Inc. (Cambridge, MA) and Patrick Pinhero of the University of Missouri, are developing a novel way to collect energy from the sun with a technology that could potentially cost pennies a yard, be imprinted on flexible materials and still draw energy after the sun has set.
Modeling and performance of electromagnetic energy harvesting from galloping oscillations
NASA Astrophysics Data System (ADS)
Dai, H. L.; Abdelkefi, A.; Javed, U.; Wang, L.
2015-04-01
The modeling and performance of a galloping-based electromagnetic energy harvester are investigated. To convert galloping oscillations into electrical energy, an electromagnetic transducer is used. A set of representative coupled equations that account for the transverse displacement of the bluff body and the induced electromagnetic current are constructed. The galloping force is modeled by using the quasi-steady approximation. The effects of the electrical load resistance on the coupled damping and onset speed of galloping are determined through a linear analysis. It is shown that the electrical load resistance strongly affects the coupled damping and hence the onset speed of galloping of the harvester. For high values of the electrical load resistance, it is demonstrated that the load resistance has a negligible impact on the onset speed of galloping. A nonlinear analysis is then performed to investigate the effects of the electrical load resistance and wind speed on the harvester’s outputs. The nonlinear normal form is first derived and validated with numerical predictions in order to characterize the type of instability for various cross-section geometries. The results show that a very good agreement is obtained between the normal form solutions and numerical predictions near Hopf bifurcation. It is also shown that, for well-defined values of wind speeds, both the transverse displacement amplitude and the generated voltage are increasing with the electrical load resistance. On the other hand, there is an optimum value of the electrical load resistance, which varies with the wind speed, at which the levels of the harvested power are maximized.
NASA Astrophysics Data System (ADS)
Shin, Seungha
All energy conversion inefficiencies begin with emission of resonant atomic motions, e.g., vibrations, and are declared as waste heat once these motions thermalize to equilibrium. The nonequilibrium energy occupancy of the vibrational modes can be targeted as a harvestable, low entropy energy source for direct conversion to electric energy. Since the lifetime of these resonant vibrations is short, special nanostructures are required with the appropriate tuning of the kinetics. These in turn require multiscale, multiphysics treatments. Atomic vibration is described with quasiparticle phonon in solid, and the optical phonon emission is dominant relaxation channel in semiconductors. These optical modes become over-occupied when their emission rate becomes larger than their decay rate, thus hindering energy relaxation and transport in devices. Effective removal of these phonons by drifting electrons is investigated by manipulating the electron distribution to have higher population in the low-energy states, thus allowing favorable phonon absorption. This is done through introduction, design and analysis of a heterobarrier conducting current, where the band gap is controlled by alloying, thus creating a spatial variation which is abrupt followed by a linear gradient (to ensure directed current). Self-consistent ensemble Monte Carlo simulations based on interaction kinetics between electron and phonon show that up to 19% of the phonon energy is converted to electric potential with an optimized GaAs/AlxGa1-xAs barrier structure over a range of current and electron densities, and this system is also verified through statistical entropy analysis. This direct energy conversion improves the device performance with lower operation temperature and enhances overall energy conversion efficiency. Through this study, the paradigm for harvesting the resonant atomic vibration is proposed, reversing the general role of phonon as only causing electric potential drop. Fundamentals pertaining to thermal energy transport and conversion are further explored by directly addressing the nonequilibria in phonon and molecular vibration. Enhancement of the laser cooling performance in molecular gas is examined by nonequilibrium interaction kinetics between molecules and photons. Thermal energy transport across interfaces and junctions is also studied, and decomposition of thermal interfacial resistance, atomic restructuring, and phonon wave features are addressed.
CapLibrate: Self-Calibration of an Energy Harvesting Power Supply with Supercapacitors
Turau, Volker
CapLibrate: Self-Calibration of an Energy Harvesting Power Supply with Supercapacitors Christian and assess models for a supercapacitor- based harvesting supply. The parameters of the models are discussed
Experimental investigation of galloping piezoelectric energy harvesters with square bluff bodies
NASA Astrophysics Data System (ADS)
Ewere, Felix; Wang, Gang; Cain, Brian
2014-10-01
In this paper, both a baseline galloping piezoelectric energy harvester (GPEH) with a square bluff body and an improved GPEH with an impact bump stop are tested in a wind tunnel in order to determine the system damping, electrical response and limit cycle oscillation (LCO) amplitude. In the baseline GPEH, harvested voltage, LCO amplitude and damping ratio vary with wind velocity and electrical load. They all increase with increasing wind velocity under the same electrical load. Under each wind velocity, the damping ratio increases from the short circuit load, reaches a peak value at the electrical load resulting in a maximum voltage, and reduces the value at the open circuit load. The LCO amplitude shows the opposite trend compared to the damping case. It decreases as the electrical resistance load increases and reaches the minimum value when the damping ratio is highest. A resistance load of 100 k? yields a maximum peak power output. The impact stop is introduced to reduce bending stresses and improve the fatigue life of the baseline GPEH. The performance of the improved GPEH depends on the stop design parameters such as gap size, stop location and contact area. Comprehensive tests were conducted to investigate the effect of each parameter on the performance of the improved GPEH and an optimal bump stop configuration was determined. Compared to the expected proportional reduction in both electrical and structural responses, a maximum 70% reduction in LCO amplitude and only a maximum 20% reduction in harvested voltage are achieved in our optimal improved GPEH. The time variable and motion dependent aerodynamic forces acting on the bluff body could contribute to this. In summary, comprehensive experimental evaluations were conducted to characterize the performance of both baseline GPEHs and improved GPEHs. The baseline GPEH service life can be significantly improved by incorporating an impact bump stop. The improved GPEH design provides a practical solution to harvest electricity from wind-induced vibration.
Piezoelectric energy harvester having planform-tapered interdigitated beams
Kellogg, Rick A. (Tijeras, NM); Sumali, Hartono (Albuquerque, NM)
2011-05-24
Embodiments of energy harvesters have a plurality of piezoelectric planform-tapered, interdigitated cantilevered beams anchored to a common frame. The plurality of beams can be arranged as two or more sets of beams with each set sharing a common sense mass affixed to their free ends. Each set thus defined being capable of motion independent of any other set of beams. Each beam can comprise a unimorph or bimorph piezoelectric configuration bonded to a conductive or non-conductive supporting layer and provided with electrical contacts to the active piezoelectric elements for collecting strain induced charge (i.e. energy). The beams are planform tapered along the entirety or a portion of their length thereby increasing the effective stress level and power output of each piezoelectric element, and are interdigitated by sets to increase the power output per unit volume of a harvester thus produced.
Harvesting human kinematical energy based on liquid metal magnetohydrodynamics
NASA Astrophysics Data System (ADS)
Jia, Dewei; Liu, Jing; Zhou, Yixin
2009-03-01
A flexible human energy harvesting generator - Liquid Metal Magnetohydrodynamics Generator (LMMG) is proposed and fabricated. Conceptual experiments were performed to investigate this electricity harvesting principle. Theoretical analysis predicts that the present method is promising at converting otherwise wasted human kinematical energy via a directional selective generation paradigm. In vitro experiment demonstrates output of 1.4 V/3.61 ?W by 5.68 g Ga 62In 25Sn 13 liquid metal with a rather high efficiency of more than 45%. The in vivo experiment actuated by a wrist swing during brisk walking with the plastic valve to rectify the flow, verified the potentiality of unidirectional actuation. This concept based on the flexible movement of LMMG is robust to supply electricity which would be important for future wearable micro/nano devices as a voltage constrained charge provider.