For comprehensive and current results, perform a real-time search at Science.gov.

1

Adaptive vibration energy harvesting

By scavenging energy from their local environment, portable electronic devices such as mobile phones, radios and wireless sensors can achieve greater run-times with potentially lower weight. Vibration energy harvesting is one such approach where energy from parasitic vibrations can be converted into electrical energy, through the use of piezoelectric and electromagnetic transducers. Parasitic vibrations come from a range of sources

Sam Behrens; John Ward; Josh Davidson

2007-01-01

2

Adaptive vibration energy harvesting

NASA Astrophysics Data System (ADS)

By scavenging energy from their local environment, portable electronic devices such as mobile phones, radios and wireless sensors can achieve greater run-times with potentially lower weight. Vibration energy harvesting is one such approach where energy from parasitic vibrations can be converted into electrical energy, through the use of piezoelectric and electromagnetic transducers. Parasitic vibrations come from a range of sources such as wind, seismic forces and traffic. Existing approaches to vibration energy harvesting typically utilise a rectifier circuit, which is tuned to the resonant frequency of the harvesting structure and the dominant frequency of vibration. We have developed a novel approach to vibration energy harvesting, including adaption to non-periodic vibrations so as to extract the maximum amount of vibration energy available. Experimental results of an experimental apparatus using off-the-shelf transducer (i.e. speaker coil) show mechanical vibration to electrical energy conversion efficiencies of 27 - 34%. However, simulations of a more electro-mechanical efficient and lightly damped transducer show conversion efficiencies in excess of 80%.

Behrens, Sam; Ward, John; Davidson, Josh

2007-04-01

3

Downhole vibration sensing by vibration energy harvesting

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 ...

Trimble, A. Zachary

2007-01-01

4

Adaptive learning algorithms for vibration energy harvesting

NASA Astrophysics Data System (ADS)

By scavenging energy from their local environment, portable electronic devices such as MEMS devices, mobile phones, radios and wireless sensors can achieve greater run times with potentially lower weight. Vibration energy harvesting is one such approach where energy from parasitic vibrations can be converted into electrical energy through the use of piezoelectric and electromagnetic transducers. Parasitic vibrations come from a range of sources such as human movement, wind, seismic forces and traffic. Existing approaches to vibration energy harvesting typically utilize a rectifier circuit, which is tuned to the resonant frequency of the harvesting structure and the dominant frequency of vibration. We have developed a novel approach to vibration energy harvesting, including adaptation to non-periodic vibrations so as to extract the maximum amount of vibration energy available. Experimental results of an experimental apparatus using an off-the-shelf transducer (i.e. speaker coil) show mechanical vibration to electrical energy conversion efficiencies of 27-34%.

Ward, John K.; Behrens, Sam

2008-06-01

5

Harvesting energy from non-ideal vibrations

Energy harvesting has drawn significant interest for its potential to power autonomous low-power applications. Vibration energy harvesting is particularly well suited to industrial condition sensing, environmental monitoring ...

Chang, Samuel C

2013-01-01

6

Adaptive learning algorithms for vibration energy harvesting

By scavenging energy from their local environment, portable electronic devices such as MEMS devices, mobile phones, radios and wireless sensors can achieve greater run times with potentially lower weight. Vibration energy harvesting is one such approach where energy from parasitic vibrations can be converted into electrical energy through the use of piezoelectric and electromagnetic transducers. Parasitic vibrations come from a

John K. Ward; Sam Behrens

2008-01-01

7

Scaling of electromagnetic vibration energy harvesting devices

NASA Astrophysics Data System (ADS)

A review of the vibration energy harvesting literature has been undertaken with the goal of establishing scaling laws for experimentally demonstrated harvesting devices. In particular electromagnetic harvesting devices are investigated. Power density metrics are examined with respect to scaling length, mass, frequency and drive acceleration. Improvements in demonstrated power density of harvesting devices over the past decade are noted. Scaling laws are observed that appear to suggest an upper limit to the power density achievable with current harvesting techniques.

Moss, Scott D.; Payne, Owen R.; Hart, Genevieve A.

2014-04-01

8

Wideband Piezomagnetoelastic Vibration Energy Harvesting

NASA Astrophysics Data System (ADS)

This work presents a small-scale wideband piezomagnetoelastic vibration energy harvester (VEH) aimed for operation at frequencies of a few hundred Hz. The VEH consists of a tape-casted PZT cantilever with thin sheets of iron foil attached on each side of the free tip. The wideband operation is achieved by placing the cantilever in a magnetic field induced by either one or two magnets located oppositely of the cantilever. The attraction force created by the magnetic field and iron foils introduces a mechanical force in opposite direction of the cantilevers restoring force causing a spring softening effect. In linear operation (without magnets) the harvester generates a RMS power of 141 ?W/g2 at 588 Hz with a relative bandwidth of 3.8% over a 100 k? load resistor. When operated with one magnet ideally positioned opposite the cantilever, a RMS power of 265 ?W/g2 is generated at 270 Hz with a relative bandwidth of 25%.

Lei, Anders; Thomsen, Erik V.

2014-11-01

9

A Miniature Coupled Bistable Vibration Energy Harvester

NASA Astrophysics Data System (ADS)

This paper reports the design and test of a miniature coupled bistable vibration energy harvester. Operation of a bistable structure largely depends on vibration amplitude rather than frequency, which makes it very promising for wideband vibration energy harvesting applications. A coupled bistable structure consists of a pair of mobile magnets that create two potential wells and thus the bistable phenomenon. It requires lower excitation to trigger bistable operation compared to conventional bistable structures. Based on previous research, this work focused on miniaturisation of the coupled bistable structure for energy harvesting application. The proposed bistable energy harvester is a combination of a Duffing's nonlinear structure and a linear assisting resonator. Experimental results show that the output spectrum of the miniature coupled bistable vibration energy harvester was the superposition of several spectra. It had a higher maximum output power and a much greater bandwidth compared to simply the Duffing's structure without the assisting resonator.

Zhu, D.; Arthur, D. C.; Beeby, S. P.

2014-11-01

10

Piezoelectric cantilevers optimization for vibration energy harvesting

NASA Astrophysics Data System (ADS)

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.

Cao, Junyi; Zhou, Shengxi; Ren, Xiaolong; Cao, Binggang

2012-04-01

11

Piezoelectric cantilevers optimization for vibration energy harvesting

NASA Astrophysics Data System (ADS)

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.

Cao, Junyi; Zhou, Shengxi; Ren, Xiaolong; Cao, Binggang

2011-11-01

12

Vibration energy harvesting by magnetostrictive material

A new class of vibration energy harvester based on magnetostrictive material (MsM), Metglas 2605SC, is designed, developed and tested. It contains two submodules: an MsM harvesting device and an energy harvesting circuit. Compared to piezoelectric materials, the Metglas 2605SC offers advantages including higher energy conversion efficiency, longer life cycles, lack of depolarization and higher flexibility to survive in strong ambient

Lei Wang; F. G. Yuan

2008-01-01

13

Harvesting Vibrational Energy Using Material Work Functions

NASA Astrophysics Data System (ADS)

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.

Varpula, Aapo; Laakso, Sampo J.; Havia, Tahvo; Kyynäräinen, Jukka; Prunnila, Mika

2014-10-01

14

Harvesting vibrational energy using material work functions.

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

Varpula, Aapo; Laakso, Sampo J; Havia, Tahvo; Kyynäräinen, Jukka; Prunnila, Mika

2014-01-01

15

Energy harvesting vibration sources for microsystems applications

This paper reviews the state-of-the art in vibration energy harvesting for wireless, self-powered microsystems. Vibration-powered generators are typically, although not exclusively, inertial spring and mass systems. The characteristic equations for inertial-based generators are presented, along with the specific damping equations that relate to the three main transduction mechanisms employed to extract energy from the system. These transduction mechanisms are: piezoelectric,

S P Beeby; M J Tudor; N M White

2006-01-01

16

Similarity and duality of electromagnetic and piezoelectric vibration energy harvesters

NASA Astrophysics Data System (ADS)

A frequency analysis has been conducted to study vibration energy harvesting performance and characteristics of a single degree of freedom vibration energy harvester connected to a single load resistor based on the Laplace transfer method and physical models of a voltage source. The performance and characteristics of electromagnetic and piezoelectric harvesters have been analysed and compared. The main research outcome is the disclosure of similarity and duality of electromagnetic and piezoelectric harvesters for both the energy harvesting efficiency and the normalised resonant harvested power using only two dimensionless characteristic parameters: the normalised resistance and the normalised force factor. The dimensionless resonant harvested power and energy harvesting efficiency analysis allows for a parameter study and optimization of the ambient vibration energy harvesters from macro- to nano-scales and for evaluation of the vibration energy harvester performance regardless of the size and type.

Wang, Xu; John, Sabu; Watkins, Simon; Yu, Xinghuo; Xiao, Han; Liang, Xingyu; Wei, Haiqiao

2015-02-01

17

Energy harvesting from wind-induced vibration of suspension bridges

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 ...

Shi, Miao, M. Eng. Massachusetts Institute of Technology

2013-01-01

18

A vibration energy harvester using magnet/piezoelectric composite transducer

NASA Astrophysics Data System (ADS)

In this research, a vibration energy harvester employing the magnet/piezoelectric composite transducer to convert mechanical vibration energy into electrical energy is presented. The electric output performance of a vibration energy harvester has been investigated. Compared to traditional magnetoelectric transducer, the proposed vibration energy harvester has some remarkable characteristic which do not need binder. The experimental results show that the presented vibration energy harvester can obtain an average power of 0.39 mW for an acceleration of 0.6g at frequency of 38 Hz. Remarkably, this power is a very encouraging power figure that gives the prospect of being able to power a widely range of wireless sensors in wireless sensor network.

Qiu, Jing; Chen, Hengjia; Wen, Yumei; Li, Ping; Yang, Jin; Li, Wenli

2014-05-01

19

Vibration energy harvesting from random force and motion excitations

NASA Astrophysics Data System (ADS)

A vibration energy harvester is typically composed of a spring-mass system with an electromagnetic or piezoelectric transducer connected in parallel with a spring. This configuration has been well studied and optimized for harmonic vibration sources. Recently, a dual-mass harvester, where two masses are connected in series by the energy transducer and a spring, has been proposed. The dual-mass vibration energy harvester is proved to be able to harvest more power and has a broader bandwidth than the single-mass configuration, when the parameters are optimized and the excitation is harmonic. In fact, some dual-mass vibration energy harvesters, such as regenerative vehicle suspensions and buildings with regenerative tuned mass dampers (TMDs), are subjected to random excitations. This paper is to investigate the dual-mass and single-mass vibration harvesters under random excitations using spectrum integration and the residue theorem. The output powers for these two types of vibration energy harvesters, when subjected to different random excitations, namely force, displacement, velocity and acceleration, are obtained analytically with closed-form expressions. It is also very interesting to find that the output power of the vibration energy harvesters under random excitations depends on only a few parameters in very simple and elegant forms. This paper also draws some important conclusions on regenerative vehicle suspensions and buildings with regenerative TMDs, which can be modeled as dual-mass vibration energy harvesters. It is found that, under white-noise random velocity excitation from road irregularity, the harvesting power from vehicle suspensions is proportional to the tire stiffness and road vertical excitation spectrum only. It is independent of the chassis mass, tire-wheel mass, suspension stiffness and damping coefficient. Under random wind force excitation, the power harvested from buildings with regenerative TMD will depends on the building mass only, not on the parameters of the TMD subsystem if the ratio of electrical and mechanical damping is constant.

Tang, Xiudong; Zuo, Lei

2012-07-01

20

A MEMS vibration energy harvester for automotive applications

NASA Astrophysics Data System (ADS)

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.

van Schaijk, R.; Elfrink, R.; Oudenhoven, J.; Pop, V.; Wang, Z.; Renaud, M.

2013-05-01

21

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. ...

Trimble, A. Zachary

2011-01-01

22

Magnetic induction systems to harvest energy from mechanical vibrations

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. ...

Jonnalagadda, Aparna S

2007-01-01

23

Evaluating vehicular-induced bridge vibrations for energy harvesting applications

NASA Astrophysics Data System (ADS)

Highway bridges are vital links in the transportation network in the United States. Identifying possible safety problems in the approximately 600,000 bridges across the country is generally accomplished through labor-intensive, visual inspections. Ongoing research sponsored by NIST seeks to improve inspection practices by providing real-time, continuous monitoring technology for steel bridges. A wireless sensor network with a service life of ten years that is powered by an integrated energy harvester is targeted. In order to achieve the target ten-year life for the monitoring system, novel approaches to energy harvesting for use in recharging batteries are investigated. Three main sources of energy are evaluated: (a) vibrational energy, (b) solar energy, and (c) wind energy. Assessing the energy produced from vehicular-induced vibrations and converted through electromagnetic induction is the focus of this paper. The goal of the study is to process acceleration data and analyze the vibrational response of steel bridges to moving truck loads. Through spectral analysis and harvester modeling, the feasibility of vibration-based energy harvesting for longterm monitoring can be assessed. The effects of bridge conditions, ambient temperature, truck traffic patterns, and harvester position on the power content of the vibrations are investigated. With sensor nodes continually recharged, the proposed real-time monitoring system will operate off the power grid, thus reducing life cycle costs and enhancing inspection practices for state DOTs. This paper will present the results of estimating the vibration energy of a steel bridge in Texas.

Reichenbach, Matthew; Fasl, Jeremiah; Samaras, Vasilis A.; Wood, Sharon; Helwig, Todd; Lindenberg, Richard

2012-04-01

24

A broadband vibrational energy harvester Louis Van Blarigan, Per Danzl, and Jeff Moehlisa)

A broadband vibrational energy harvester Louis Van Blarigan, Per Danzl, and Jeff Moehlisa for an energy harvester which has the potential to harvest vibrational energy over a broad range of ambient in the absence of vibrations. Experimental data show that this design allows enhanced harvesting of energy

Bigelow, Stephen

25

Demonstration of Energy-Neutral Operation on a WSN Testbed Using Vibration Energy Harvesting

for harvesting are generally from radio-frequency (RF) power conversion, solar energy conversion and vibration-to-electrical energy conversion The RF harvester is used in [7] to increase primary battery lifetime of the ultraDemonstration of Energy-Neutral Operation on a WSN Testbed Using Vibration Energy Harvesting S

Uysal-Biyikoglu, Elif

26

Piezoelectric energy harvesting from traffic-induced bridge vibrations

NASA Astrophysics Data System (ADS)

This paper focuses on energy harvesting from traffic-induced vibrations in bridges. Using a pre-stressed concrete highway bridge as a case study, in situ vibration measurements are presented and analysed. From these results, a prototype of a cantilever piezoelectric harvester is designed, tested and modelled. Even though the considered bridge vibrations are characterized by small amplitude and a low frequency (i.e. below 15 Hz), it is shown that mean power of the order of 0.03 mW can be produced, with a controlled voltage between 1.8 and 3.6 V. A simple model is proposed for theoretical prediction of the delivered power in terms of traffic intensity. This model shows good agreement with the experimental results and leads to a simple but effective design rule for piezoelectric harvesters to be used on bridges.

Peigney, Michaël; Siegert, Dominique

2013-09-01

27

A Branched Beam-Based Vibration Energy Harvester

NASA Astrophysics Data System (ADS)

In this paper, a strategy to utilize a branched beam system to improve the frequency response characteristic of vibration energy harvesting is demonstrated. A basic unit of the device consists of several branch beams with proof mass at their ends and one main cantilever beam with a piezoelectric component at its root and proof mass at its end. The device can utilize the resonance of the branch beams and main beam to generate multiple output voltage peaks, providing a better frequency response characteristic than that of the conventional piezoelectric vibration energy harvester. Multiple branch structure and multiple basic units with similar structures can be connected to generate more output voltage peaks in the frequency response characteristic. Only one piezoelectric component is needed in the device, which makes it competitive in the management of harvested electric energy.

Zhang, Guangcheng; Hu, Junhui

2014-09-01

28

A Branched Beam-Based Vibration Energy Harvester

NASA Astrophysics Data System (ADS)

In this paper, a strategy to utilize a branched beam system to improve the frequency response characteristic of vibration energy harvesting is demonstrated. A basic unit of the device consists of several branch beams with proof mass at their ends and one main cantilever beam with a piezoelectric component at its root and proof mass at its end. The device can utilize the resonance of the branch beams and main beam to generate multiple output voltage peaks, providing a better frequency response characteristic than that of the conventional piezoelectric vibration energy harvester. Multiple branch structure and multiple basic units with similar structures can be connected to generate more output voltage peaks in the frequency response characteristic. Only one piezoelectric component is needed in the device, which makes it competitive in the management of harvested electric energy.

Zhang, Guangcheng; Hu, Junhui

2014-11-01

29

DEAP-based energy harvesting using vortex-induced vibrations

NASA Astrophysics Data System (ADS)

Generators based on dielectric electroactive polymers (DEAP) convert mechanical strain energy into electrical field energy. In order to harvest renewable energy from ambient sources adequate generator setups have to be developed. Thus, in this contribution a DEAP generator is presented which uses periodic vortex induced vibration of a circular cylinder as excitation mechanism, by which e.g. Flow energy of a wind or water current can be converted. For this purpose a novel generator design consisting of a cylinder that is elastically mounted on DEAP material is presented. Since the effect of vortex induced vibrations depends on the stiffness and damping of the utilized generator's eigenmode, a method to adapt both via the electrostatic pressure and energy conversion is proposed. After the validation of the general functionality of the novel generator design, analyses concerning the control of the overall harvester are carried out.

Hoffstadt, Thorben; Heinze, Robert; Wahl, Tim; Kameier, Frank; Maas, Jürgen

2014-03-01

30

Energy harvester array using piezoelectric circular diaphragm for broadband vibration

NASA Astrophysics Data System (ADS)

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.

Xiao, Zhao; Yang, Tong qing; Dong, Ying; Wang, Xiu cai

2014-06-01

31

Resonant frequency tuning of an industrial vibration energy harvester

NASA Astrophysics Data System (ADS)

This paper presents preliminary results of tuning the resonant frequency of two industrial vibration energy harvesters. The VEH-450 from Ferro Solutions and the PMG17-50 from Perpetuum were tested using discrete reactive electrical loads. The former could be tuned to +0.5 Hz and -2 Hz from its natural resonant frequency of 50.5 Hz at 0.1g. The latter, however, has a broadband output power spectrum that spans ±10 Hz and its output voltage saturates at 7 Vrms, thereby rendering it un-tunable using the method presented here. A comparison of output power between a tuned VEH-450 and an un-tuned PMG17-50, normalised by harvester weight, shows that the former outperforms the latter only at a tuned frequency of 49.8 Hz. A discussion of a resonant frequency tuning circuit that can be fitted to an existing harvester without making modifications to the harvester is presented.

Toh, T. T.; Wright, S. W.; Mitcheson, P. D.

2014-11-01

32

A Bistable Vibration Energy Harvester with Closed Magnetic Circuit

NASA Astrophysics Data System (ADS)

In this work, to increase magnetic flux passing through the electric coil in a bistable vibration energy harvester, the magnetic circuit is made closed by introducing two coil systems which have magnetic core in their axis holes. The magnetic resistance of the magnetic circuit, composed of silicon steel and thin air gaps, is supressed to be small. The double well potential is realized from the spring force and nonlinear magnetic force between the magnets and the magnetic core. Two harvesters with opened and closed magnetic circuits are manufactured for comparison. It is also shown that the closed magnetic circuit can effectively improve the output power.

Sato, Takahiro; Sugisawa, Takeshi; Igarashi, Hajime

2014-11-01

33

Model reduction in stochastic vibration energy harvesting using compressive sampling

NASA Astrophysics Data System (ADS)

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.

Wickenheiser, A. M.

2013-09-01

34

Enhanced vibration based energy harvesting using embedded acoustic black holes

NASA Astrophysics Data System (ADS)

In this paper, we investigate the use of dynamic structural tailoring via the concept of an Acoustic Black Hole (ABH) to enhance the performance of piezoelectric based energy harvesting from operational mechanical vibrations. The ABH is a variable thickness structural feature that can be embedded in the host structure allowing a smooth reduction of the phase velocity while minimizing the amplitude of reflected waves. The ABH thickness variation is typically designed according to power-law profiles. As a propagating wave enters the ABH, it is progressively slowed down while its wavelength is compressed. This effect results in structural areas with high energy density that can be exploited effectively for energy harvesting. The potential of ABH for energy harvesting is shown via a numerical study based on fully coupled finite element electromechanical models of an ABH tapered plate with surface mounted piezo-transducers. The performances of the novel design are evaluated by direct comparison with a non-tapered structure in terms of energy ratios and attenuation indices. Results show that the tailored structural design allows a drastic increase in the harvested energy both for steady state and transient excitation. Performance dependencies of key design parameters are also investigated.

Zhao, L.; Semperlotti, F.; Conlon, S. C.

2014-03-01

35

Multistable chain for ocean wave vibration energy harvesting

NASA Astrophysics Data System (ADS)

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.

Harne, R. L.; Schoemaker, M. E.; Wang, K. W.

2014-03-01

36

Vibration energy harvesting via parametrically-induced bistability

NASA Astrophysics Data System (ADS)

The dynamic response to white Gaussian noise of a bistable non-linear vibration energy harvester based on the repulsive electrostatic interaction between a microcantilever and an electrode has been theoretically studied. The cantilever-electrode system can be brought from a linear regime characterized by a quadratic potential, when cantilever is far from the electrode, to a non-linear bistable regime characterized by a quartic potential, when both elements are close enough. This distance parameter, which is commonly used to tune bistability, is unusually used here also to inject the energy to the system in the form of displacement noise. Thus, the widening and shifting to the low-frequency region of the response spectrum as well as the enhancement of the rms out-of-plane vibration of the cantilever are both demonstrated through this parametrically-induced bistability.

Abadal, G.; López, M.; Venstra, W. J.; Murillo, G.; Torres, F.

2014-11-01

37

A piezomagnetoelastic structure for broadband vibration energy harvesting

NASA Astrophysics Data System (ADS)

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).

Erturk, A.; Hoffmann, J.; Inman, D. J.

2009-06-01

38

Efficiency enhancement of a cantilever-based vibration energy harvester.

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

Kubba, Ali E; Jiang, Kyle

2013-01-01

39

Harvesting energy from the natural vibration of human walking.

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

Yang, Weiqing; Chen, Jun; Zhu, Guang; Yang, Jin; Bai, Peng; Su, Yuanjie; Jing, Qingsheng; Cao, Xia; Wang, Zhong Lin

2013-12-23

40

Multi-link piezoelectric structure for vibration energy harvesting

NASA Astrophysics Data System (ADS)

Work in piezoelectric vibration energy harvesting has typically focused on single member cantilevered structures with transverse tip displacement at a known frequency, taking advantage of the optimal coupling characteristics of piezoceramics in the 3-1 bending mode. Multi-member designs could be advantageous in delivering power to a load in environments with random or wide-band vibrations. The design presented in this work consists of two hinged piezoceramic (PZT-5A) beams x-poled for series operation. Each beam measures 31.8mm x 12.7mm x 0.38mm and consists of two layers of nickel-plated piezoceramic adhered to a brass center shim. The hinge device consists of two custom-machined aluminum attachments epoxied to the end of a beam and connected using a 1.59mm diameter alloy steel dowel. A stainless steel torsion spring is placed over the pin and attached to the aluminum body to provide a restoring torque when under rotation. The design is modeled using the piezoelectric constitutive equations to solve for voltage and power for a set of electromechanical boundary conditions. Experimental measurements on the design are achieved by bolting one end of the structure to a vibration shaker and fixing the other to a rigid framework of industrial aluminum framing material. For a given frequency of vibration, power output of the structure can be obtained by measuring voltage drop across a resistive load.

Aryanpur, Rameen M.; White, Robert D.

2012-04-01

41

Harvesting vibration energy by a triple-cantilever based triboelectric nanogenerator

University Press and Springer-Verlag Berlin Heidelberg 2013 KEYWORDS triboelectric nanogenerator, harvestingHarvesting vibration energy by a triple-cantilever based triboelectric nanogenerator Weiqing Yang1 vibration energy, triple-cantilever, self-powered systems ABSTRACT Triboelectric nanogenerators (TENG

Wang, Zhong L.

42

INCREASED-BANDWIDTH, MEANDERING VIBRATION ENERGY HARVESTER D. F. Berdy1,3

in a low-frequency, meandering piezoelectric vibration energy harvester. The fabricated device features twoINCREASED-BANDWIDTH, MEANDERING VIBRATION ENERGY HARVESTER D. F. Berdy1,3 , B. Jung1 , J. F. Rhoads, piezoelectric, distributed mass, meander INTRODUCTION Decreasing power requirements and an increasing need

Rhoads, Jeffrey F.

43

Vibration-based energy harvesting with stacked piezoelectrets

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.

Pondrom, P., E-mail: ppondrom@nt.tu-darmstadt.de [Institute for Telecommunications Technology, Technische Universität Darmstadt, Merckstr. 25, 64283 Darmstadt (Germany); System Reliability and Machine Acoustics SzM, Technische Universität Darmstadt, Magdalenenstr. 4, 64289 Darmstadt (Germany); Hillenbrand, J.; Sessler, G. M. [Institute for Telecommunications Technology, Technische Universität Darmstadt, Merckstr. 25, 64283 Darmstadt (Germany); Bös, J.; Melz, T. [System Reliability and Machine Acoustics SzM, Technische Universität Darmstadt, Magdalenenstr. 4, 64289 Darmstadt (Germany)

2014-04-28

44

A chaotic vibration energy harvester using magnetic material

NASA Astrophysics Data System (ADS)

This paper presents a new wideband electromagnetic vibration energy harvester (VEH) composed of a magnetic core embedded into the coil axis. The magnetic core generates a nonlinear magnetic force, which gives rise to the nonlinearity in the behavior of the VEH. Moreover, the magnetic core increases the flux linkage with the coil. These features improve the operational bandwidth and output power of the VEH. Numerical analysis and experimental measurements reveal that the operational bandwidth of the proposed VEH is over 30 Hz in which the output power is kept about 0.1 mW. Moreover, the proposed VEH operates by complicated oscillation due to nonlinear forces acting on the oscillator. Evaluation of the Lyapunov exponent for the measured oscillation suggests that the proposed VEH produces chaotic oscillation.

Sato, Takahiro; Igarashi, Hajime

2015-02-01

45

New nonlinear vibration energy harvesters based on PVDF hybrid fluid diaphragm

NASA Astrophysics Data System (ADS)

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.

Huet, F.; Formosa, F.; Badel, A.

2014-11-01

46

NASA Astrophysics Data System (ADS)

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.

Beeby, Stephen P.; Wang, Leran; Zhu, Dibin; Weddell, Alex S.; Merrett, Geoff V.; Stark, Bernard; Szarka, Gyorgy; Al-Hashimi, Bashir M.

2013-07-01

47

MEMS electrostatic vibration energy harvester without switches and inductive elements

NASA Astrophysics Data System (ADS)

The paper is devoted to a novel study of monophase MEMS electrostatic Vibration Energy Harvester (e-VEH) with conditioning circuit based on Bennet's doubler. Unlike the majority of conditioning circuits that charge a power supply, the circuit based on Bennet's doubler is characterized by the absence of switches requiring additional control electronics, and is free from hardly compatible with batch fabrication process inductive elements. Our experiment with a 0.042 cm3 batch fabricated MEMS e-VEH shows that a pre-charged capacitor as a power supply causes a voltage increase, followed by a saturation which was not reported before. This saturation is due to the nonlinear dynamics of the system and the electromechanical damping that is typical for MEMS. It has been found that because of that coupled behavior there exists an optimal power supply voltage at which output power is maximum. At 187 Hz / 4 g external vibrations the system is shown to charge a 12 V supply with a output power of 1.8 ?W.

Dorzhiev, V.; Karami, A.; Basset, P.; Dragunov, V.; Galayko, D.

2014-11-01

48

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.

Cryns, Jackson W.; Hatchell, Brian K.; Santiago-Rojas, Emiliano; Silvers, Kurt L.

2013-07-01

49

Smart nanocoated structure for energy harvesting at low frequency vibration

NASA Astrophysics Data System (ADS)

Increasing demands of energy which is cleaner and has an unlimited supply has led development in the field of energy harvesting. Piezoelectric materials can be used as a means of transforming ambient vibrations into electrical energy that can be stored and used to power other devices. With the recent surge of micro scale devices, piezoelectric power generation can provide a convenient alternative to traditional power sources. In this research, a piezoelectric power generator composite prototype was developed to maximize the power output of the system. A lead zirconate titanate (PZT) composite structure was formed and mounted on a cantilever bar and was studied to convert vibration energy of the low range vibrations at 30 Hz--1000 Hz. To improve the performance of the PZT, different coatings were made using different percentage of Ferrofluid (FNP) and Zinc Oxide nanoparticles (ZnO) and binder resin. The optimal coating mixture constituent percentage was based on the performance of the composite structure formed by applying the coating on the PZT. The fabricated PZT power generator composite with an effective volume of 0.062 cm3 produced a maximum of 44.5 ?W, or 0.717mW/cm3 at its resonant frequency of 90 Hz. The optimal coating mixture had the composition of 59.9%FNP + 40% ZnO + 1% Resin Binder. The coating utilizes the opto-magneto-electrical properties of ZnO and Magnetic properties of FNP. To further enhance the output, the magneto-electric (ME) effect was increased by subjecting the composite to magnetic field where coating acts as a magnetostrictive material. For the effective volume of 0.0062 cm 3, the composite produced a maximum of 68.5 ?W, or 1.11mW/cm 3 at its resonant frequency of 90 Hz at 160 gauss. The optimal coating mixture had the composition of 59.9% FNP + 40% ZnO + 1% Resin Binder. This research also focused on improving the efficiency of solar cells by utilizing the magnetic effect along with gas plasma etching to improve the internal reflection. Preliminary results showed an improvement in solar cell efficiency from 14.6% to 17.1%.

Sharma, Sudhanshu

50

NASA Astrophysics Data System (ADS)

Micro-fabricated piezoelectric vibration energy harvesters with resonance frequencies of 31-232 Hz are characterized and deployed for testing on ambient vibration sources in the machine room of a large building. A survey of 23 ambient vibration sources in the machine room is presented. A model is developed which uses a discretization method to accept measured arbitrary acceleration data as an input and gives harvester response as output. The modeled and measured output from the energy harvesters is compared for both vibrometer and ambient vibration sources. The energy harvesters produced up to 43 nWrms g-2 on a laboratory vibrometer and 10 nW g-2 on ambient vibration sources typically in large buildings.

Miller, L. M.; Halvorsen, E.; Dong, T.; Wright, P. K.

2011-04-01

51

Scaling and power density metrics of electromagnetic vibration energy harvesting devices

NASA Astrophysics Data System (ADS)

A review of the vibration energy harvesting literature has been undertaken with the goal of establishing scaling laws for experimentally demonstrated harvesting devices based on electromagnetic transduction. Power density metrics are examined with respect to scaling length, mass, frequency and drive acceleration. Continuous improvements in demonstrated power density of harvesting devices over the past decade are noted. Scaling laws are developed from observations that appear to suggest an upper limit to the power density achievable with current harvesting techniques.

Moss, Scott D.; Payne, Owen R.; Hart, Genevieve A.; Ung, Chandarin

2015-02-01

52

Output power of piezoelectric MEMS vibration energy harvesters under random oscillations

NASA Astrophysics Data System (ADS)

Environmental vibrations include random oscillations of different frequencies and amplitudes. Energy harvesters recover the energy associated with these vibrations. Properties of the vibrations and output power are characterized for cantilever-type piezoelectric vibration energy harvesters using (100)-orientated BiFeO3 films subject to both ideal and random oscillations. The displacement and output power under random oscillations were smaller than those under ideal oscillations. This decrease originates with the decreasing acceleration of the fundamental wave with the spurious component having little influence on the resonance response.

Kariya, K.; Yoshimura, T.; Murakami, S.; Fujimura, N.

2014-11-01

53

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

Kumar, Ratnesh

54

NASA Astrophysics Data System (ADS)

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

Miller, Lindsay Margaret

55

Piezoelectric energy harvesting devices for low frequency vibration applications

NASA Astrophysics Data System (ADS)

Energy harvesting, a process of capturing ambient waste energy and converting it into usable electricity, has been attracting more and more researchers' interest because of the limitations of traditional power sources, the increasing demands upon mobile devices such as wireless sensor networks, and the recent advent of the extremely low power electrical and mechanical devices such as microelectromechanical systems (MEMS). In this research, bulk- and wafer-scale of piezoelectric power generator prototypes were developed. The Lead Zirconate Titanate (PZT) bimorph cantilever in bulk scale with a big proof mass at the free end tip was studied to convert ambient vibration energy of 100 Hz and above 1g (1g = 9.81 m/s2) acceleration amplitudes. The optimal design was based on matching the resonant frequency of the device with the environmental exciting frequency, and balancing the power output and the fracture safety factor. The fabricated PZT power generator with an effective volume of 0.0564 cm3 and a safety factor of 10g can produce 6.21 Vpk, 257 microW, or 4558 microW/cm 3 with an optimal resistive load of 75 kO from 1g acceleration at its resonant frequency of 97.6 Hz. To overcome the high fragility of PZT, substitute piezoelectric materials, Macro Fiber Composite (MFC) and polyvinylidene fluoride (PVDF), and alternative operational ambient for power generators were investigated for high vibration amplitude applications. Before fabricating piezoelectric power generators in wafer scale, interlayer effects on the properties of PZT thin film were surveyed. The fabricated device based on Si wafer, with a beam dimension about 4.800 mm x 0.400 mm x 0.036 mm and an integrated Si mass dimension about 1.360 mm x 0.940 mm x 0.456 mm produced 160 mVpk, 2.13 microW, or 3272 microW/cm3 with the optimal resistive load of 6 kO from 2g acceleration at its resonant frequency of 461.15 Hz. To precisely control the resonant frequency of the power generator, Si on insulator (SOI) wafer substitutes for Si wafer. The resonant frequency of the fabricated device is as low as about 184 Hz. The difference between the calculated and measured resonant frequency has been decreased to 4.25%.

Shen, Dongna

56

Enhanced vibration energy harvesting using dual-mass systems Xiudong Tang, Lei Zuo n

,7]. Because of its ubiquitous existence, vibration becomes a very promising alternative energy sourceEnhanced vibration energy harvesting using dual-mass systems Xiudong Tang, Lei Zuo n Department i n f o Article history: Received 1 September 2010 Received in revised form 16 May 2011 Accepted 17

Zuo, Lei

57

Investigation of folded spring structures for vibration-based piezoelectric energy harvesting

NASA Astrophysics Data System (ADS)

This paper presents a fixed-fixed folded spring as an alternative elastic element for beam-based piezoelectric energy harvesting. In order to harvest energy from low frequency vibration in an optimal manner, the natural/operational frequencies of harvesters must be reduced to match low frequency input vibrations. Therefore, natural frequency reduction of vibration-based energy harvesters is critical to maximize output power at low operational frequency. The mechanical optimization of cantilever-based piezoelectric energy harvesters is limited by residual stress-based beam curling that produced through microfabrication adding additional mechanical stiffness to the system. The fixed-fixed folded spring structure presented in this paper allows for increased effective beam length and residual stress relaxation, without out of plane beam curling to further reducing the natural frequency. Multiple designs of folded spring energy harvesters are presented to demonstrate the effect of important design parameters. It is shown that the folded spring harvesters were capable of harvesting electricity at low natural frequencies, ranging from 45?Hz to 3667?Hz. Additionally, the harvesters were shown to be insensitive to microfabrication-based residual stress beam curling. The maximum power output achieved by the folded spring harvesters was 690.5?nW at 226.3?Hz for a single harvesting element of an array, with a PZT layer thickness of 0.24??m. The work presented in this paper demonstrates that the fixed-fixed folded spring can be used as a viable structural element for low frequency piezoelectric energy harvesting to take advantage of ambient vibrations found in low frequency applications.

Lueke, J.; Rezaei, M.; Moussa, W. A.

2014-12-01

58

Piezoelectric energy harvesting devices for low frequency vibration applications

Energy harvesting, a process of capturing ambient waste energy and converting it into usable electricity, has been attracting more and more researchers' interest because of the limitations of traditional power sources, the increasing demands upon mobile devices such as wireless sensor networks, and the recent advent of the extremely low power electrical and mechanical devices such as microelectromechanical systems (MEMS).

Dongna Shen

2009-01-01

59

A Hybrid Indoor Ambient Light and Vibration Energy Harvester for Wireless Sensor Nodes

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

Yu, Hua; Yue, Qiuqin; Zhou, Jielin; Wang, Wei

2014-01-01

60

A hybrid indoor ambient light and vibration energy harvester for wireless sensor nodes.

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

Yu, Hua; Yue, Qiuqin; Zhou, Jielin; Wang, Wei

2014-01-01

61

Energy harvesting and vibration control using piezoelectric elements and a nonlinear approach

The piezoelectric materials, as the most widely used functional materials in smart structures, have many outstanding advantages for sensors and actuators, especially in vibration control and energy harvesting, because of their excellent mechanical-electrical coupling characteristics and frequency response characteristics. Semi-active vibration control based on state switching and pulse switching, have been receiving much attention over the past decade because of

J. H. Qiu; H. L. Ji; H. Shen

2009-01-01

62

NASA Astrophysics Data System (ADS)

A mismatch between the ambient frequency and the resonant frequency of the vibrational energy harvester causes decrease of the energy transduction efficiency. Therefore, there is a great demand for the resonant frequency tuning of the vibrational energy harvester. In this paper, a flexible PVDF (polyvinylidene fluoride) cantilever, which can switch its resonant frequency automatically and maintain the switched resonant frequency without energy consumption, is proposed. The proposed energy harvester is composed of cantilever couples which are similar with a seesaw structure. When the proposed energy harvester is excited by an external vibration and the excited frequency fluctuates, the cantilever couples can be horizontally moved by using the large deflection of a flexible cantilever. So the beam length of each cantilever which corresponds to each arm of the seesaw structure can be changed and the resonant frequency of the proposed energy harvester can be switched in real time. The proposed energy harvester was realized by application of a piezoelectric polymer, PVDF. Also, it was confirmed that the proposed energy harvester can switch its resonant frequency in several seconds without an additional energy source.

Jo, Sung-Eun; Kim, Myoung-Soo; Kim, Yong-Jun

2012-01-01

63

Energy harvesting from underwater torsional vibrations of a patterned ionic polymer metal composite

NASA Astrophysics Data System (ADS)

In this paper, we study underwater energy harvesting from torsional vibrations of an ionic polymer metal composite (IPMC) with patterned electrodes. We focus on harmonic base excitation of a centimeter-size IPMC, which is modeled as a slender beam with thin cross-section vibrating in a viscous fluid. Large-amplitude torsional vibrations are described using a complex hydrodynamic function, which accounts for added mass and nonlinear hydrodynamic damping from the surrounding fluid. A linear black box model is utilized to predict the IPMC electrical response as a function of the total twist angle. Model parameters are identified from in-air transient response, underwater steady-state vibrations, and electrical discharge experiments. The resulting electromechanical model allows for predicting energy harvesting from the IPMC as a function of the shunting resistance and the frequency and amplitude of the base excitation. Model results are validated against experimental findings that demonstrate power harvesting densities on the order of picowatts per millimeter cubed.

Cha, Youngsu; Shen, Linfeng; Porfiri, Maurizio

2013-05-01

64

NASA Astrophysics Data System (ADS)

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.

Renaud, M.; Fujita, T.; Goedbloed, M.; de Nooijer, C.; van Schaijk, R.

2014-11-01

65

Tunable Vibration Energy Harvester for Condition Monitoring of Maritime Gearboxes

NASA Astrophysics Data System (ADS)

This paper reports on a new tuning concept, which enables the operation of a vibration generator for energy autonomous condition monitoring of maritime gearboxes. The tuning concept incorporates a circular tuning magnet, which interacts with a coupling magnet attached to the active transducer element. The tuning range can be tailored to the application by careful design of the gap between tuning magnet and coupling magnet. A total rotation angle of only 180° is required for the tuning magnet in order to obtain the full frequency bandwidth. The tuning concept is successfully demonstrated by charging a 0.6 F capacitor on the basis of physical vibration profiles taken from a gearbox.

Hoffmann, D.; Willmann, A.; Folkmer, B.; Manoli, Y.

2014-11-01

66

NASA Astrophysics Data System (ADS)

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.

Bibo, A.; Daqaq, M. F.

2013-06-01

67

Broadband electromagnetic vibration energy harvesting system for powering wireless sensor nodes

NASA Astrophysics Data System (ADS)

This paper reports the design of an electromagnetic vibration energy harvesting system that provides high power density and broad bandwidth. The ‘double cell’ harvester was chosen as the generator for this system. In order to harvest power over a broad range of frequencies, four ‘double cell’ harvesters with varying resonances were incorporated in the system architecture. The average AC to regulated DC power conversion efficiency across the 4 Hz bandwidth was 78%, which is one of the highest reported magnitudes for an electromagnetic vibration harvesting system. The magnetic flux density variation within the double cell array was modeled using the finite element method and compared to a single cell with equivalent tip mass and magnet volume. The double cell array was found to generate a similar magnitude of power to a single cell but three times higher bandwidth. The average generator conversion efficiency for the double cell array was 45.3%, which approaches the maximum theoretical limit of 50%.

Marin, Anthony; Turner, John; Ha, Dong Sam; Priya, Shashank

2013-07-01

68

NASA Astrophysics Data System (ADS)

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 mm3, which was designed for a target frequency of as low as 100 Hz.

Sun, Kyung Ho; Kim, Young-Cheol; Kim, Jae Eun

2014-10-01

69

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.

Sun, Kyung Ho; Kim, Young-Cheol [Department of System Dynamics, Korea Institute of Machinery and Materials, 156 Gajeongbuk-Ro, Yuseong-Gu, Daejeon 305-343 (Korea, Republic of); Kim, Jae Eun, E-mail: jekim@cu.ac.kr [School of Mechanical and Automotive Engineering, Catholic University of Daegu, 13-13 Hayang-Ro, Hayang-Eup, Gyeongsan-Si, Gyeongsangbuk-Do 712-702 (Korea, Republic of)

2014-10-15

70

Design improvements for an electret-based MEMS vibrational electrostatic energy harvester

NASA Astrophysics Data System (ADS)

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).

Altena, G.; Renaud, M.; Elfrink, R.; Goedbloed, M. H.; de Nooijer, C.; van Schaijk, R.

2013-12-01

71

NASA Astrophysics Data System (ADS)

This paper presents an optimal design for a system comprising a nonlinear energy sink (NES) and a piezoelectric-based vibration energy harvester attached to a free-free beam under shock excitation. The energy harvester is used for scavenging vibration energy dissipated by the NES. Grounded and ungrounded configurations are examined and the systems parameters are optimized globally to both maximize the dissipated energy by the NES and increase the harvested energy by piezoelectric element. A satisfactory amount of energy has been harvested as electric power in both configurations. The realization of nonlinear vibration control through one-way irreversible nonlinear energy pumping and optimizing the system parameters result in acquiring up to 78 percent dissipation of the grounded system energy.

Nili Ahmadabadi, Z.; Khadem, S. E.

2014-09-01

72

Conversion of ambient vibrational energy into electric power has been the impetus of much modern research. The traditional analysis has focused on absolute electrical power output from the harvesting devices and efficiency defined as the convertibility of an infinite resource of vibration excitation into power. This perspective has limited extensibility when applying resonant harvesters to host resonant structures when the inertial influence of the harvester is more significant. Instead, this work pursues a fundamental understanding of the coupled dynamics of a main mass-spring-damper system to which an electromagnetic or piezoelectric mass-spring-damper is attached. The governing equations are derived, a metric of efficiency is presented, and analysis is undertaken. It is found that electromagnetic energy harvesting efficiency and maximum power output is limited by the strength of the coupling such that no split system resonances are induced for a given mass ratio. For piezoelectric harvesters, only the coupling strength and certain design requirements dictate maximum power and efficiency achievable. Since the harvesting circuitry must "follow" the split resonances as the piezoelectric harvesters become more massive, the optimum design of piezoelectric harvesters appears to be more involved than for electromagnetic devices. PMID:22779465

Harne, Ryan L

2012-07-01

73

NASA Astrophysics Data System (ADS)

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.

Lan, C. B.; Qin, W. Y.

2014-09-01

74

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.

Lan, C. B.; Qin, W. Y. [Department of Engineering Mechanics, Northwestern Polytechnical University, Xi'an 710072 (China)

2014-09-15

75

NASA Astrophysics Data System (ADS)

In this paper, a wide-band vibration energy harvester using a nonlinear hardening oscillator with self-excitation circuit is presented. A vibration energy harvester is one of the energy-harvesting devices that collects unused energy from vibrating environment. For the conventional linear vibration energy harvester, the resonance frequency is matched to the source frequency, and the mechanical Q factor is designed as large as possible to maximize the oscillator's amplitude. The large Q factor, however, bounds the resonance in a narrow frequency band, and the performance of the vibration energy harvester can become extremely worth when the frequency of the vibration source fluctuates. As is well known, the resonance frequency band can be expanded by introducing a hardening (or softening) nonlinear oscillator. However, it is difficult for the nonlinear vibration energy harvester to maintain the regenerated power constant because such nonlinear oscillator can have multiple stable steady-state solutions in the resonance band. In this paper, a control law that switches the load resistance between positive and negative values according to the instantaneous displacement and the velocity is proposed to give the oscillator a self-excitation capability, which ensures the oscillator entrained by the excitation only in the largest amplitude solution. Moreover, an adaptive adjustment of the control law is proposed to quicken the entrainment process. Numerical analysis shows that the nonlinear vibration energy harvester with resistance switching can maintain the large amplitude response even when the excitation frequency abruptly changes.

Masuda, Arata; Senda, Atsuko

2012-04-01

76

Scavenging vibration energy from seismically isolated bridges using an electromagnetic harvester

NASA Astrophysics Data System (ADS)

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.

Lu, Qiuchen; Loong, Chengning; Chang, Chih-Chen; Dimitrakopoulos, Elias G.

2014-04-01

77

NASA Astrophysics Data System (ADS)

Based on the research results of conventional rigid support nonlinear energy harvesters, in this paper we conceive a kind of structure with an elastic support external magnet with the intent to keep the system in the state of bistable oscillation, even under low-intensity excitation conditions. It has been proved that elastic support systems have better power output performance than rigid support systems when excited at low-intensity vibrations. In addition, elastic support nonlinear energy harvesters do not need real-time adjustment of the magnet interval towards the variable-intensity random excitation source, consequently achieving maximum power output and sufficient electromechanical energy conversion of the system.

Gao, Y. J.; Leng, Y. G.; Fan, S. B.; Lai, Z. H.

2014-09-01

78

NASA Astrophysics Data System (ADS)

A mass-spring-damper system is at the core of both a vibration absorber and a harvester of energy from ambient vibrations. If such a device is attached to a structure that has a high impedance, then it will have very little effect on the vibrations of the structure, but it can be used to convert mechanical vibrations into electrical energy (act as an energy harvester). However, if the same device is attached to a structure that has a relatively low impedance, then the device may attenuate the vibrations as it may act as both a vibration absorber and an energy harvester simultaneously. In this paper such a device is discussed. Two situations are considered; the first is when the structure is excited with broadband random excitation and the second is when the structure is excited by a single frequency. The optimum parameters of the device for both energy harvesting and vibration attenuation are discussed for these two cases. For random excitation it is found that if the device is optimized for vibration suppression, then this is also adequate for maximizing the energy absorbed (harvested), and thus a single device can effectively suppress vibration and harvest energy at the same time. For single frequency excitation this is found not to be the case. To maximize the energy harvested, the natural frequency of the system (host structure and absorber) has to coincide with the forcing frequency, but to minimize vibration of the host structure, the natural frequency of the absorber has to coincide with the forcing frequency. In this case, therefore, a single resonator cannot effectively suppress vibration and harvest energy at the same time.

Brennan, M. J.; Tang, B.; Melo, G. Pechoto; Lopes, V.

2014-02-01

79

NASA Astrophysics Data System (ADS)

The minimum transducer coupling to enable maximum theoretical power capture from vibration energy harvesters is derived, leading to the simple conclusion that the product of the transducer coupling coefficient and resonance quality factor must be greater than two. Maximum theoretical power capture is experimentally demonstrated on a micromachined piezoelectric energy harvester comprised of a 20 ?m thick epitaxial silicon cantilever with 800 nm thick lead-zirconate-titanate along the top surface and a bulk silicon mass at the tip. The coupling of these structures, although small (?2=0.0033), is entirely sufficient to enable maximum theoretical power capture owing to light damping (Q =906).

Kim, D.; Hewa-Kasakarage, N. N.; Yoon, S.; Hall, N. A.

2012-09-01

80

A two-dimensional broadband vibration energy harvester using magnetoelectric transducer

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})

Yang, Jin, E-mail: yangjin@cqu.edu.cn; Wen, Yumei; Li, Ping; Yue, Xihai; Yu, Qiangmo; Bai, Xiaoling [Department of Optoelectronic Engineering, Research Center of Sensors and Instruments, Chongqing University, Chongqing 400044 (China)] [Department of Optoelectronic Engineering, Research Center of Sensors and Instruments, Chongqing University, Chongqing 400044 (China)

2013-12-09

81

An evaluation on low-level vibration energy harvesting using piezoelectret foam

NASA Astrophysics Data System (ADS)

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.

Anton, S. R.; Farinholt, K. M.

2012-04-01

82

NASA Astrophysics Data System (ADS)

We present electroelastic modeling, analytical and numerical solutions, and experimental validations of piezoelectric energy harvesting from broadband random vibrations. The modeling approach employed herein is based on a distributed-parameter electroelastic formulation to ensure that the effects of higher vibration modes are included, since broadband random vibrations, such as Gaussian white noise, might excite higher vibration modes. The goal is to predict the expected value of the power output and the mean-square shunted vibration response in terms of the given power spectral density (PSD) or time history of the random vibrational input. The analytical method is based on the PSD of random base excitation and distributed-parameter frequency response functions of the coupled voltage output and shunted vibration response. The first of the two numerical solution methods employs the Fourier series representation of the base acceleration history in an ordinary differential equation solver while the second method uses an Euler-Maruyama scheme to directly solve the resulting electroelastic stochastic differential equations. The analytical and numerical simulations are compared with several experiments for a brass-reinforced PZT-5H bimorph under different random excitation levels. The simulations exhibit very good agreement with the experimental measurements for a range of resistive electrical boundary conditions and input PSD levels. It is also shown that lightly damped higher vibration modes can alter the expected power curve under broadband random excitation. Therefore, the distributed-parameter modeling and solutions presented herein can be used as a more accurate alternative to the existing single-degree-of-freedom solutions for broadband random vibration energy harvesting.

Zhao, S.; Erturk, A.

2013-01-01

83

NASA Astrophysics Data System (ADS)

Piezoelectric energy microgenerators are devices that continuously generate electricity when they are subjected to varying mechanical strain due to vibrations. They can generate electrical power up to 100 ?W which can be used to drive various sensing and actuating MEMS devices. Today, piezoelectric energy harvesters are considered autonomous and reliable energy sources to actuate low power microdevices such as wireless sensor networks, indoor-outdoor monitoring, facility management and biomedical applications. The advantages of piezoelectric energy harvesters including high power density, moderate output power and CMOS compatible fabrication in particular with aluminum nitride (AlN) have fuelled and motivated researchers to develop MEMS based energy harvesters. Recently, the use of AlN as a piezoelectric material has increased fabrication compatibility, enabling the realization of smart integrated systems on chip which include sensors, actuators and energy storage. Piezoelectric MEMS energy microgenerator is used to capture and transform the available ambient mechanical vibrations into usable electric energy via resonant coupling in the thin film piezoelectric material. Analysis and modeling of piezoelectric energy generators are very important aspects for improved performance. Aluminum nitride as the piezoelectric material is sandwiched between two electrodes. The device design includes a silicon cantilever on which the AlN film is deposited and which features a seismic mass at the end of the cantilever. Beam theory and lumped modeling with circuit elements are applied for modeling and analysis of the device operation at various acceleration values. The model shows good agreement with the experimental findings, thus giving confidence in the model.

Alamin Dow, Ali B.; Al-Rubaye, Hasan A.; Koo, David; Schneider, Michael; Bittner, Achim; Schmid, Ulrich; Kherani, Nazir P.

2011-06-01

84

NASA Astrophysics Data System (ADS)

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.

Betts, David N.; Bowen, Christopher R.; Inman, Daniel J.; Weaver, Paul M.; Kim, H. A.

2014-04-01

85

NASA Astrophysics Data System (ADS)

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.

Muthalif, Asan G. A.; Nordin, N. H. Diyana

2015-03-01

86

A micromachined low-frequency piezoelectric harvester for vibration and wind energy scavenging

NASA Astrophysics Data System (ADS)

To efficiently scavenge ambient vibration energy and wind energy at the same time, a low-frequency piezoelectric harvester was designed, fabricated and tested. A lumped-parameter model of the cantilevered piezoelectric energy harvester with a proof mass was established and the closed-form expressions of voltage and power on a resistance load under base acceleration excitation were derived. After effects of the lengths of the proof mass and electrodes on output power were analyzed, a MEMS harvester was optimally designed. By using aluminum nitride as piezoelectric layer, a MEMS energy harvester was fabricated with bulk micromachining process. Experimental results show that the open-circuit frequency of the MEMS harvester is about 134.8 Hz and the matched resistance is about 410 k?. Under the harmonic acceleration excitation of ±0.1 g, the maximum output power is about 1.85 µW, with the normalized power density of about 6.3 mW cm-3 g-2. The critical wind speed of the device is between 12.7 and 13.2 m s-1 when the wind direction is from the proof mass to the fixed end of the cantilever. The maximum output power under 16.3 m s-1 wind is about 2.27 µW.

He, Xuefeng; Shang, Zhengguo; Cheng, Yaoqing; Zhu, You

2013-12-01

87

Harvesting broadband kinetic impact energy from mechanical triggering/vibration and water waves.

We invented a triboelectric nanogenerator (TENG) that is based on a wavy-structured Cu-Kapton-Cu film sandwiched between two flat nanostructured PTFE films for harvesting energy due to mechanical vibration/impacting/compressing using the triboelectrification effect. This structure design allows the TENG to be self-restorable after impact without the use of extra springs and converts direct impact into lateral sliding, which is proved to be a much more efficient friction mode for energy harvesting. The working mechanism has been elaborated using the capacitor model and finite-element simulation. Vibrational energy from 5 to 500 Hz has been harvested, and the generator's resonance frequency was determined to be ?100 Hz at a broad full width at half-maximum of over 100 Hz, producing an open-circuit voltage of up to 72 V, a short-circuit current of up to 32 ?A, and a peak power density of 0.4 W/m(2). Most importantly, the wavy structure of the TENG can be easily packaged for harvesting the impact energy from water waves, clearly establishing the principle for ocean wave energy harvesting. Considering the advantages of TENGs, such as cost-effectiveness, light weight, and easy scalability, this approach might open the possibility for obtaining green and sustainable energy from the ocean using nanostructured materials. Lastly, different ways of agitating water were studied to trigger the packaged TENG. By analyzing the output signals and their corresponding fast Fourier transform spectra, three ways of agitation were evidently distinguished from each other, demonstrating the potential of the TENG for hydrological analysis. PMID:24964297

Wen, Xiaonan; Yang, Weiqing; Jing, Qingshen; Wang, Zhong Lin

2014-07-22

88

Electric control of power extracting end-stop for MEMS vibration energy harvesting

NASA Astrophysics Data System (ADS)

This experimental work investigates a technique to further improve performance of vibration energy harvesters under displacement-constrained operation. Previously, a device concept based on end-stops acting as additional transducers was developed so that the harvested power can be increased beyond the power obtained from a conventional harvester of the same size. However, there is a range of tested acceleration amplitudes in which the transducing end- stop device performs worse than the conventional device. In this paper, an approach using electric control is used to optimize the end-stop transducer performance and thereby further improve the system effectiveness under displacement constrained operation. For example, the maximum power increases by a factor of 2.4 compared to that of a conventional prototype under the same operating conditions and constrained displacement amplitude, while this value was about 1.3 for the previous technique.

Truong, Binh Duc; Phu Le, Cuong; Halvorsen, Einar

2014-11-01

89

Probability-of-existence of vibro-impact regimes in a nonlinear vibration energy harvester

NASA Astrophysics Data System (ADS)

This paper reports on the characterization of high-energy vibro-impacting regimes in a vibration energy harvester with softening Duffing nonlinearity, by mathematical modelling and numerical analysis with experimental validation. The harvester is implemented as a base excited permanent-magnet/ball-bearing arrangement, where oscillations by the ball-bearing induce a change in magnetic flux in a wire coil, which in turn generates a voltage. Symmetric rigid aluminum stops in the harvester structure restrain the amplitude of the ball-bearing motion (within gap ?) and thus produce vibro-impact behaviour under certain operating conditions—leading to wideband operation. These operating conditions are analysed by means of an event-driven equation switching algorithm, implementing a base-driven Duffing oscillator with conditional hyster-Hertz impact mechanics. In considering the ‘probability-of-existence’ of impact regimes, predictions about the frequency bandwidth of the high-energy impact state are made and compared to the experimental prototype. A trade-off between operating bandwidth and output power is noted. For the non-optimized harvester arrangement examined in this paper, with a gap ? = 14.7 mm the bandwidth was predicted to be ˜1.3 Hz, and was measured at 0.7 Hz with an output power of 7.4 mW rms. With a gap size ? = 2.9 mm the bandwidth was predicted to be ˜7.2 Hz, and was measured at 6.1 Hz with an output power of 54 ?W rms. The authors believe that the probability-of-existence approach may be useful for characterizing the conditions required for exciting high-energy states of other nonlinear vibration energy harvesting systems.

Vandewater, L. A.; Moss, S. D.

2013-09-01

90

Vibration Energy Harvesting Characterization of 1 cm2 Poly(vinylidene fluoride) Generators in Vacuum

NASA Astrophysics Data System (ADS)

In this study, poly(vinylidene fluoride) (PVDF) was used as a piezoelectric element to fabricate small size (two-dimensional area <1 cm2) generators with low resonant frequency (about 100 Hz) for matching the frequency of vibration sources. To clarify the effect of the air damping on the vibration energy harvesting, PVDF generators were investigated in three measurement conditions: “unpackaged in air”, “packaged in air”, and “unpackaged in vacuum”. It was found that the output power of generators “unpackaged in vacuum” was almost twice that of generators “packaged in air” at 0.5g acceleration. With the increase in vibration acceleration, the output power of generators “unpackaged in vacuum” rapidly increased in a quadratic relationship with the acceleration at low acceleration level, and then the increasing ratio decreased at high acceleration. At 4.31g acceleration, the output power reached 100.833 µW.

Cao, Ziping; Zhang, Jinya; Kuwano, Hiroki

2011-09-01

91

NASA Astrophysics Data System (ADS)

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.

Hobeck, J. D.; Inman, D. J.

2014-11-01

92

NASA Astrophysics Data System (ADS)

Piezoelectric vibration energy harvesters with multi-layer stacked structures have been developed. They consist of multi-layer beams, of zigzag configurations, with rigid masses attached between the beams. The rigid masses, which also serve as spacers, are attached to each layer to tune the frequencies of the harvester. Close resonance frequencies and considerable power output can be achieved in multiple modes by varying the positions of the masses. A modal approach is introduced to determine the modal performance conveniently using the mass ratio and the modal electromechanical coupling coefficient, and the required modal parameters are derived using the finite element method. Mass ratio represents the influence of modal mechanical behaviour on the power density. Since the modes with larger mass ratios cause the remaining modes to have smaller mass ratios and lower power densities, a screening process using the modal approach is developed to determine the optimal or near-optimal performance of the harvesters when altering mass positions. This procedure obviates the need for full analysis by pre-selecting the harvester configurations with close resonances and favourable values of mass ratio initially. Furthermore, the multi-layer stacked designs using the modal approach can be used to develop harvesters with different sizes with the power ranging from microwatts to milliwatts.

Xiong, Xingyu; Oyadiji, S. Olutunde

2014-10-01

93

A vibration-based MEMS piezoelectric energy harvester and power conditioning circuit.

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

Yu, Hua; Zhou, Jielin; Deng, Licheng; Wen, Zhiyu

2014-01-01

94

NASA Astrophysics Data System (ADS)

A magnetoelectric (ME) vibration energy harvester has been designed to scavenge sufficient energy from ambient vibration with arbitrary motion directions in a plane and over a range of frequencies. In the harvester, a circular-cross-section cantilever rod is adopted to extract the vibration energy due to its ability to host accelerations in arbitrary in-plane motion directions. The magnetic coupling between the magnet and the ME transducer results in nonlinear oscillation of the cantilever rod with increased frequency bandwidth. To achieve optimal vibration energy harvesting performance, the effects of the nonlinear vibration and the harvester parameters including the magnetic circuit and the separation distance on the electrical output and the?working bandwidth are analyzed. The experimental results show that the harvester can scavenge vibration energy in arbitrary in-plane directions, exhibiting a bandwidth of 4.0 Hz and maximum power of 0.22 mW at acceleration of 0.6 g (with g = 9.8 m s-2).

Yang, Jin; Wen, Yumei; Li, Ping; Yue, Xihai; Yu, Qiangmo

2014-07-01

95

Piezoelectric Vibrational Energy Harvester Using Lead-Free Ferroelectric BiFeO3 Films

NASA Astrophysics Data System (ADS)

We have proposed that BiFeO3 films are suitable for piezoelectric vibrational energy harvester (VEH) applications, because BiFeO3 has high spontaneous polarization and low dielectric permittivity. We demonstrated that energy can be harvested by a micromachined VEH using a BiFeO3 film deposited using a sol-gel process. A VEH with a resonant frequency of ˜98 Hz produced an output voltage of 1.5 V·G-1 and electrical power of 2.8 µW·mm-3·G-2 (G=9.8 m/s2) at a load resistance of 1 M?. Using the analytical model for VEH, the generalized electromechanical coupling factor was estimated to be 0.41%. These results were comparable to those of the best-performing VEHs using other piezoelectric films.

Yoshimura, Takeshi; Murakami, Shuichi; Wakazono, Keisuke; Kariya, Kento; Fujimura, Norifumi

2013-05-01

96

Topology optimization and fabrication of low frequency vibration energy harvesting microdevices

NASA Astrophysics Data System (ADS)

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.

Deng, Jiadong; Rorschach, Katherine; Baker, Evan; Sun, Cheng; Chen, Wei

2015-02-01

97

NASA Astrophysics Data System (ADS)

This paper presents analytical modeling and case studies of broadband and band-limited random vibration energy harvesting using a piezoceramic patch attached on a thin plate. The literature of vibration-based energy harvesting has been mostly focused on resonant cantilevered structures. However, cantilevered beam-type harvesters have limited broadband vibration energy harvesting capabilities unless they are combined with a nonlinear component. Moreover, cantilever arrangements cannot always be mounted on thin structures (which are basic components of marine, aerospace, and ground transportation systems) without significantly affecting the host system's design and overall dynamics. A patch-based piezoelectric energy harvester structurally integrated to a thin plate can be a proper alternative to using resonant cantilevers for harvesting energy from thin structures. Besides, plate-like structures have more number of vibration modes compared to beam structures, offering better broadband performance characteristics. In this paper, we present analytical modelling of patch-based piezoelectric energy harvester attached on a thin plate for random vibrations. The analytical model is based on electromechanically-coupled distributed-parameter formulation and validated by comparing the electromechanical frequency response functions (FRFs) with experimental results. Example case studies are then presented to investigate the expected power output of a piezoceramic patch attached on an aluminum plate for the case of random force excitations. The effect of bandwidth of random excitation on the mean power and shunted mean-square vibration response are explored with a focus on the number of vibration modes covered in the frequency range of input power spectral density (PSD).

Aridogan, Ugur; Basdogan, Ipek; Erturk, Alper

2014-04-01

98

NASA Astrophysics Data System (ADS)

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.

Ye, Zhitong; Duan, Zhiyong; Takahata, Kenichi; Su, Yufeng

2014-08-01

99

NASA Astrophysics Data System (ADS)

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.

Ye, Zhitong; Duan, Zhiyong; Takahata, Kenichi; Su, Yufeng

2015-01-01

100

NASA Astrophysics Data System (ADS)

We present a low frequency vibration driven 2-DOF piezoelectric energy harvester with increased performance, in terms of both bandwidth and output power, by mechanical impact. It consists of two series spring-mass systems (positioned in a parallel manner) one of which responds to low frequency vibration, engages with the harvester base stopper periodically by piecewise linear impact, and transfers a secondary shock to the second spring- mass system comprising of power generating element. It introduces a non-linear frequency up- conversion mechanism which, in turn, generates increased output power within a wide range of applied frequency. A 2-DOF prototype harvester without stopper shows two narrow resonant peaks and delivers maximum 2.11?W peak power to its matched load resistance at 17Hz frequency and 0.5g acceleration. On the other hand, it offers a -3dB bandwidth of 15Hz (9Hz- 24Hz) and delivers maximum 202.4?W peak power to its matched load resistance at the same operating condition when a stopper is placed below the primary mass at 0.5mm distance. Generated power increases up to 449?W as the acceleration increases to 1g.

Halim, M. A.; Park, J. Y.

2014-11-01

101

Vibration energy harvesting using the nonlinear oscillations of a magnetostrictive material

NASA Astrophysics Data System (ADS)

A novel magnetostrictive-material-based device concept to convert ambient mechanical vibration into electricity has been designed, fabricated, and tested. In order to harvest energy over a greater frequency range as compared to state-of- the-art devices, an L-shaped beam which is tuned so that the first two (bending) natural frequencies have a (near) two-to-one ratio is used as a mechanical transducer to generate nonlinear oscillations. Under harmonic excitation, an internal resonance or autoparametric, dynamic response can occur in which one vibration mode parametrically excites a second vibration mode resulting in significant displacement of both modes over an extended frequency range. A magnetostrictive material, Metglas 2605SA1, is used to convert vibration into electricity. Vibration-induced strain in the Metglas changes its magnetization which in turn generates current in a coil of wire. Metglas is highly flexible so it can undergo large displacement and does not fatigue under extended excitation. Demonstration devices are used to study how this nonlinear response can be exploited to generate electricity under single-frequency, harmonic and random base excitation.

Tsutsumi, Erika; del Rosario, Zachary; Lee, Christopher

2012-04-01

102

NASA Astrophysics Data System (ADS)

This paper presents an advanced study including the design, characterization and theoretical analysis of a capacitive vibration energy harvester. Although based on a resonant electromechanical device, it is intended for operation in a wide frequency band due to the combination of stop-end effects and a strong biasing electrical field. The electrostatic transducer has an interdigited comb geometry with in-plane motion, and is obtained through a simple batch process using two masks. A continuous conditioning circuit is used for the characterization of the transducer. A nonlinear model of the coupled system ‘transduce-conditioning circuit’ is presented and analyzed employing two different semi-analytical techniques together with precise numerical modelling. Experimental results are in good agreement with results obtained from numerical modelling. With the 1 g amplitude of harmonic external acceleration at atmospheric pressure, the system transducer-conditioning circuit has a half-power bandwidth of more than 30% and converts more than 2 µW of the power of input mechanical vibrations over the range of 140 and 160 Hz. The harvester has also been characterized under stochastic noise-like input vibrations.

Basset, P.; Galayko, D.; Cottone, F.; Guillemet, R.; Blokhina, E.; Marty, F.; Bourouina, T.

2014-03-01

103

NASA Astrophysics Data System (ADS)

Basic research of MEMS based micro devices for vibration energy harvesting using vinylidene fluoride / trifluoroethylene (VDF/TrFE) copolymer thin film was investigated. The VDF/TrFE copolymer thin film was formed by spin coating. Thickness of VDF/TrFE copolymer thin film was ranged from 375 nm to 2793 nm. Impedance of VDF/TrFE copolymer thin film was measured by LCR meter. Thin film in each thickness was fully poled by voltage based on C-V characteristics result. Generated power of the devices under applied vibration was observed by an oscilloscope. When the film thickness is 2793 nm, the generated power was about 0.815 ?J.

Takiguchi, T.; Sasaki, T.; Nakajima, T.; Yamaura, S.; Sekiguchi, T.; Shoji, S.

2014-11-01

104

Semi-active controller design for vibration suppression and energy harvesting via LMI approach

NASA Astrophysics Data System (ADS)

The vibration control plays an important role in energy harvesting systems. Compared to the active control, semi-active control is a more preferred alternative for practical use. Many different semi-active control strategies have been developed, among which LQ-clip, Skyhook and model predictive control are the most popular strategies in literatures. In this paper, a different control strategy that designs semi-active controller via LMI approach is proposed. Different from clipping the control input after controller construction like most existing control methods, the proposed method fulfills the semi-active control input feasibility constraints before the controller construction. The methodology is developed through LMI approach which leads to a stabilizing linear controller to ensure semi-active constraint and the pre-designed performance. An illustrative example, vibration control system of a tall building, is presented to show the efficiency of the method and validate the new approach.

Liu, Yilun; Lin, Chi-Chang; Zuo, Lei

2014-04-01

105

Novel optimized design of a piezoelectric energy harvester in a package for low amplitude vibrations

NASA Astrophysics Data System (ADS)

This paper presents a novel piezoelectric energy harvesting device created with the flip-chip bonding of two different parts, one is a MEMS die which plays the role of inertial mass and the other is an associate CMOS chip anchored to the vibrating environment. The flip-chip bonding is performed between the MEMS die, which consists of four piezoelectric beams connected to four PADs or anchor points, and a test PCB, which is used to validate the feasibility of the whole assembled system. The resulting system in package is a proof of concept of a novel design concept that increases the extracted power from an ambient vibration. FEM simulations have been carried out to study the mechanical behaviour of the who le system. Moreover, the fabrication of the piezoelectric die and the test PCB has been successfully performed, as well as their flip-chip integration.

Murillo, G.; Campanella, H.; Esteve, J.; Abadal, G.

2013-12-01

106

NASA Astrophysics Data System (ADS)

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.

Li, Peng; Zhang, Chongxiao; Kim, Junyoung; Yu, Liangyao; Zuo, Lei

2014-04-01

107

NASA Astrophysics Data System (ADS)

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.

Shen, Li; Wu, Jiu Hui; Zhang, Siwen; Liu, Zhangyi; Li, Jing

2015-01-01

108

Design of a Step-Down AC-DC Converter for Energy Harvesting System Using Vibration-Based Energy

To realize battery-free operation employing energy harvesting, a step-down switched-capacitor-based converter has been used as a vibration-to-electricity converter. In this paper, to improve power efficiency, a step-down ACDC converter realizing 1\\/N (N=2,3,... ) conversion modes is designed by using switched-capacitor techniques. Although conventional converters offer an output by regulating the stored energy in a big capacitor, the proposed converter generates

Kei Eguchi; Sawai Pongswatd; Hirofumi Sasaki; Kitti Tirasesth; Tatsuya Sugimura; Takahiro Inoue

2009-01-01

109

Analysis of Piezoelectric Materials for Energy Harvesting Devices under High-g Vibrations

NASA Astrophysics Data System (ADS)

We analyzed the miniaturized energy harvesting devices (each volume within 0.3 cm3) fabricated by using three types of piezoelectric materials such as lead zirconium titanate (PZT) ceramic, macro fiber composite (MFC) and poly(vinylidene fluoride) (PVDF) polymer to investigate the capability of converting mechanical vibration into electricity under larger vibration amplitudes or accelerations conditions (? 1g, gravitational acceleration). All prototypes based on a bimorph cantilever structure with a proof mass were aimed to operate at a vibration frequency of 100 Hz. PZT-based device was optimized and fabricated by considering the resonant frequency, the output power density, and the maximum operating acceleration or safety factor. PVDF- and MFC-prototypes were designed to have same resonant frequency as well as same volume of the piezoelectric materials as the PZT prototype. All three devices were measured to determine if they could generate enough power density to provide electric energy to power a wireless sensor or a microelectromechanical systems (MEMS) device without device failure.

Shen, Dongna; Choe, Song-Yul; Kim, Dong-Joo

2007-10-01

110

White Noise Responsiveness of an AlN Piezoelectric MEMS Cantilever Vibration Energy Harvester

NASA Astrophysics Data System (ADS)

This paper reports the design, analysis and experimental characterisation of a piezoelectric MEMS cantilever vibration energy harvester, the enhancement of its power output by adding various values of end mass, as well as assessing the responsiveness towards white noise. Devices are fabricated using a 0.5 ?m AlN on 10 ?m doped Si process. Cantilevers with 5 mm length and 2 mm width were tested at either unloaded condition (MC0: fn 577 Hz) or subjected to estimated end masses of 2 mg (MC2: fn 129 Hz) and 5 mg (MC5: fn 80 Hz). While MC0 was able to tolerate a higher drive acceleration prior to saturation (7 g with 0.7 ?W), MC5 exhibited higher peak power attainable at a lower input vibration (2.56 ?W at 3 ms?2). MC5 was also subjected to band-limited (10 Hz to 2 kHz) white noise vibration, where the power response was only a fraction of its resonant counterpart for the same input: peak instantaneous power >1 ?W was only attainable beyond 2 g of white noise, whereas single frequency resonant response only required 2.5 ms?2. Both the first resonant response and the band-limited white noise response were also compared to a numerical model, showing close agreements.

Jia, Y.; Seshia, A. A.

2014-11-01

111

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

Khan, Farid; Stoeber, Boris; Sassani, Farrokh

2014-01-01

112

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

Sassani, Farrokh

2014-01-01

113

Modeling and Tuning for Vibration Energy Harvesting using a Piezoelectric Bimorph

NASA Astrophysics Data System (ADS)

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.

Cao, Yongqing

114

NASA Astrophysics Data System (ADS)

This research work presents the design, fabrication and characterization of micromachined piezoelectric energy harvester stimulated by ambient random vibrations utilizing AlN as a piezoelectric material. The device design consists of a silicon cantilever beam on which AlN is sandwiched between two electrodes and a silicon seismic mass at the end of the cantilever beam. The generated electric power of the devices was experimentally measured at various acceleration levels. A maximum power of 34 ?W was obtained at an acceleration value of 2g for the device which measures 5.6 x 5.6 mm2. Various unpackaged devices were tested and assessed in terms of the generated power and resonant frequency at various acceleration values.

Alamin Dow, Ali B.; Bittner, Achim; Schmid, Ulrich; Kherani, Nazir P.

2013-05-01

115

Note: A cubic electromagnetic harvester that convert vibration energy from all directions.

We investigate the output performance of a cubic harvester which can scavenge low-frequency vibration energy from all directions. By adjusting the size and shape of the inside magnets, higher induced voltages and output power can be achieved. The optimal magnet is found to be cubic shape with the length of 6.35 mm (25.6% volume ratio), which can generate 4.27 mV root mean square voltage and 2.45 ?W average power at the frequency of 28.86 Hz and acceleration of 1.17 g. The device is also demonstrated as a self-powered tilt sensor by measuring induced voltages at different tilt angles. PMID:25085194

Han, Mengdi; Qiu, Guolin; Liu, Wen; Meng, Bo; Zhang, Xiao-Sheng; Zhang, Haixia

2014-07-01

116

Comparison of Five Topologies of Cantilever-based MEMS Piezoelectric Vibration Energy Harvesters

NASA Astrophysics Data System (ADS)

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.

Jia, Y.; Seshia, A. A.

2014-11-01

117

Reliability of vibration energy harvesters of metal-based PZT thin films

NASA Astrophysics Data System (ADS)

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.

Tsujiura, Y.; Suwa, E.; Kurokawa, F.; Hida, H.; Kanno, I.

2014-11-01

118

NASA Astrophysics Data System (ADS)

This note proposes a performance-enhanced piezoelectric energy harvester by replacing a conventional flat cantilevered beam with a corrugated beam. It consists of a proof mass and a sinusoidally or trapezoidally corrugated cantilevered beam covered by a polyvinylidene fluoride (PVDF) film. Compared to the conventional energy harvester of the same size, it has a more flexible bending stiffness and a larger bonding area of the PVDF layer, so higher output voltage from the device can be expected. In order to investigate the characteristics of the proposed energy harvester, analytical developments and numerical simulations on its natural frequency and tip displacement are carried out. Shaking table tests are also conducted to verify the performance of the proposed device. It is clearly shown from the tests that the proposed energy harvester not only has a lower natural frequency than an equivalent sized standard energy harvester, but also generates much higher output voltage than the standard one.

Kim, In-Ho; Jin, SeungSeop; Jang, Seon-Jun; Jung, Hyung-Jo

2014-03-01

119

An Innovative Controller to Increase Harvested Energy

NASA Astrophysics Data System (ADS)

This paper proposes an innovative energy-harvesting controller to increase energy harvested from vibrations. Energy harvesting is a process that removes mechanical energy from a vibrating structure, which necessarily results in damping. The damping associated with piezoelectric energy harvesting suppresses the amplitude of mechanical vibration and reduces the harvested energy. To address this critical problem, we devise an energy-harvesting controller that maintains the vibration amplitude as high as possible to increase the harvested energy. Our proposed switching controller is designed to intentionally stop the switching action intermittently. We experimentally demonstrate that the proposed control scheme successfully increases the harvested energy. The piezoelectric voltage with the proposed controller is larger than that with the original synchronized switching harvesting on inductor (SSHI) technique, which increases the harvested energy. The stored energy with our controller is up to 5.7 times greater than that with the conventional SSHI control scheme.

Makihara, K.; Yamamoto, Y.; Horiguchi, C.; Sakaguchi, H.; Fujimoto, K.

2014-11-01

120

NASA Astrophysics Data System (ADS)

The reduction of power consumption of sensors allows the local power supply or wireless sensor networks. This paper introduces the results of design and experiments on devices for harvesting energy from vibrations of machines. The main contribution of this research is the empirical evaluation of different technical solutions able to improve harvester performances and sensing system duty cycle. Satisfactory results have been achieved in lowering of resonance by levitating suspensions and in increasing of Q-factor by studying the air flows. Output power values of 10mW (5.7Hz, 1.4g) and 115mW (3.2Hz, 0.2g) were obtained for piezoelectric and inductive harvesters respectively.

Somà, A.; De Pasquale, G.

2013-05-01

121

Development of energy harvester system for avionics

NASA Astrophysics Data System (ADS)

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.

Hadas, Z.; Vetiska, V.; Ancik, Z.; Ondrusek, C.; Singule, V.

2013-05-01

122

NASA Astrophysics Data System (ADS)

This manuscript is motivated by research that shows the shear, d15, mode energy harvesters offer significant improvement in power generation over the traditional normal, d31, mode based harvesters. The premise behind this study is to examine the effect of expanding the design domain of PZT based energy harvesters by considering an arbitrary poling angle. In the first part of the manuscript, we derive the equation of motions of a harvester based on Timoshenko beam theory in an unimorph configuration. The resulting equations are solved using a Rayleigh Ritz analysis. The electric displacement depends on both the normal and shear strain. Thus the proposed device operates using a combination of shear and normal modes to extract power. The extent to which each mode is used depends on the polarization orientation. We examine the effect of poling on the fundamental short and open circuit frequencies. Next, the poling angle is examined over a range to determine the effect on the power harvested at the fundamental modal frequencies of the system. The study demonstrates that an arbitrary poled piezoelectric increases the power that the harvester produces over traditionally poled devices; however, the performance is highly dependent on the geometry.

Gibert, James M.

2014-04-01

123

Analysis and Modelling towards Hybrid Piezo-Electromagnetic Vibrating Energy Harvesting Devices

NASA Astrophysics Data System (ADS)

The efficiency of mobile electrical devices increased over the last years. Self-supply by harvesting ambient energy became a possibility of reducing operational costs by ruling out the need of battery replacement. Many energy harvesting devices employ cantilever configurations with base excitation to increase the effective displacement. The proposed design extends this design with an electromagnetic harvesting device (EMH) placed at its tip. It features an alternating stack of magnets with opposing poles and discs of highly permeable material. The composite cylinder is encircled by coils. This EMH design has successfully been employed for ocean wave harvesting and vehicle suspension systems. Its efficiency with respect to mass and energy output is compared to a previously published design using a single magnet placed at the tip moving within a coil. There exists proof that combining readily available technologies into a so-called coupled or hybrid design can increase the efficiency in comparison to respective stand-alone designs. Once the model for the proposed design is derived and evaluated, it is extended by a cantilevered excitation. Piezoelectric layers for hybrid harvesting may be included in future research.

Reuschel, Torsten; Salehian, Armaghan

2011-11-01

124

Extremely low-loss rectification methodology for low-power vibration energy harvesters

NASA Astrophysics Data System (ADS)

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.

Tiwari, R.; Ryoo, K.; Schlichting, A.; Garcia, E.

2013-06-01

125

Piezoelectric MEMS for energy harvesting

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 ...

Kim, Sang-Gook

126

Ultra wide-bandwidth micro energy harvester

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 ...

Hajati, Arman

2011-01-01

127

Multimodal energy harvesting system

NASA Astrophysics Data System (ADS)

Conventionally, piezoelectric materials are used to harvest the mechanical energy. However, we show that in the environment where both mechanical and magnetic field energy are available magnetoelectric mechanism can provide higher output power. A laminate structure with morphology metglas / PZT / brass / PZT / metglas was designed and tested under the conditions of (i) vibrations only and (ii) vibration and magnetic field together (dual mode). The results for both hard and soft PZT structure demonstrate that dual mode lead to improved output power. These results are quite important for applications such as powering of sensors used in health monitoring of electromagnetic motors.

Bedekar, Vishwas; Bichurin, Mirza; Solovjev, Ivan; Priya, Shashank

2011-06-01

128

An autoparametric energy harvester

NASA Astrophysics Data System (ADS)

This paper presents a numerical study of an autoparametric system composed of two elements: a pendulum and an excited nonlinear oscillator. Owing to an inertial coupling between the two elements, different types of motion are possible, from periodic to chaotic. This study examines a linear induction of an energy harvester depending on the pendulum motion. The harvester consists of a cylindrical permanent magnet mounted on a rotor and of four windings fixed to the housing as a stator. When the pendulum is rotating or swinging, the converter is generating energy due to magnetic induction. In this paper, a method utilizing parametrical resonance for harvesting energy from low frequency vibrations is studied. The authors compare energy induced by different types of pendulum motion: swinging, rotation and chaotic dynamics. Additionally, voltage values for different parameters of excitation are estimated.

Kecik, K.; Borowiec, M.

2013-09-01

129

NASA Astrophysics Data System (ADS)

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.

Halim, M. A.; Cho, H. O.; Park, J. Y.

2014-11-01

130

Powering a wireless sensor node with a vibration-driven piezoelectric energy harvester

NASA Astrophysics Data System (ADS)

This paper discusses the direct application of scavenged energy to power a wireless sensor platform. A trapezoidal piezoelectric harvester was designed for a specific machine tool application and tested for robustness and longevity as well as performance. The design focused on resonant performance and distributed strain concentrations at a given resonant frequency and acceleration. Critical issues of power coupling and conditioning between harvester and wireless platform were addressed. The wireless platform consisted of a sensor, controller, power conditioning circuitry, and a custom low power radio. The system transmitted a sensor sample once every 10 s in a scavenging environment of 0.25 g and 100 Hz for a system duty cycle of approximately 0.2%.

Reilly, Elizabeth K.; Burghardt, Fred; Fain, Romy; Wright, Paul

2011-12-01

131

Rotor hub vibration and blade loads reduction, and energy harvesting via embedded radial oscillator

NASA Astrophysics Data System (ADS)

An embedded radial absorber is investigated to control helicopter rotor hub vibration and blade loads. The absorber is modeled as a discrete mass moving in the spanwise direction within the blade. The absorber is retained in place and tuned with a spring and a damper. The radial absorber couples with lead-lag dynamic through Coriolis forces. The embedded radial absorber coupled to the helicopter is analyzed with a comprehensive rotorcraft model. The blade is modeled as an elastic beam undergoing flap bending, lag bending and elastic torsion, and a radial degree of freedom is added for the absorber. The tuning of the embedded radial absorber to a frequency close to 3/rev with no damping is shown to reduce significantly (up to 86%) the 4/rev in-plane hub forces of a 4-bladed hingeless rotor similar to a MBB BO-105 in high speed flight. The simulation shows that the absorber modifies the in-plane blade root shears to synchronize them to cancel each other in the transmission from rotating frame to fixed frame. A design of an embedded radial absorber experiment for hub vibration control is presented and it is concluded that for such high tuning frequencies as 3/rev, it is feasible to use a regular coil spring to compensate for the steady centrifugal force. Large reduction of blade lag shear (85%) and lag bending moment (71%) is achieved by tuning the embedded radial absorber close to 1/rev (also shown for a BO-105 like helicopter in high speed flight). The absorber reduces the amplitude of the lag bending moment at 1/rev, thus reducing the blade lead-lag motion and reducing the blade drag shear and lag bending moment. Finally, the use of the embedded radial absorber is investigated as a source electrical power when combined with an electromagnetic circuit. A model of the electromagnetic system is developed and validated, and an evaluation of the amount of power harvestable for different configurations is presented. The maximum power harvested was calculated to be 133 watts.

Austruy, Julien

132

Design of electromagnetic energy harvesters for large-scale structural vibration applications

NASA Astrophysics Data System (ADS)

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.

Cassidy, Ian L.; Scruggs, Jeffrey T.; Behrens, Sam

2011-03-01

133

Vibration shape effects on the power output in piezoelectric vibro-impact energy harvesters

NASA Astrophysics Data System (ADS)

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.

Twiefel, Jens

2013-04-01

134

Tunable nonlinear piezoelectric vibration harvester

NASA Astrophysics Data System (ADS)

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.

Neiss, S.; Goldschmidtboeing, F.; Kroener, M.; Woias, P.

2014-11-01

135

Dynamic analysis of an electrostatic energy harvesting system

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 ...

Niu, Feifei

2013-01-01

136

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

Liberzon, Daniel

137

Noise powered nonlinear energy harvesting

NASA Astrophysics Data System (ADS)

The powering of small-scale electronic mobile devices has been in recent years the subject of a great number of research efforts aimed primarily at finding an alternative solution to standard batteries. The harvesting of kinetic energy present in the form of random vibrations (from non-equilibrium thermal noise up to machine vibrations) is an interesting option due to the almost universal presence of some kind of motion. Present working solutions for vibration energy harvesting are based on oscillating mechanical elements that convert kinetic energy via capacitive, inductive or piezoelectric methods. These oscillators are usually designed to be resonantly tuned to the ambient dominant frequency. However, in most cases the ambient random vibrations have their energy distributed over a wide spectrum of frequencies, especially at low frequency, and frequency tuning is not always possible due to geometrical/dynamical constraints. We present a new approach to the powering of small autonomous sensors based on vibration energy harvesting by the exploitation of nonlinear stochastic dynamics. Such a method is shown to outperform standard linear approaches based on the use of resonant oscillators and to overcome some of the most severe limitations of present strategies, like narrow bandwidth, need for continuous frequency tuning and low power efficiency. We demonstrate the superior performances of this method by applying it to piezoelectric energy harvesting from ambient vibration.

Gammaitoni, Luca; Neri, Igor; Vocca, Helios

2011-04-01

138

NASA Astrophysics Data System (ADS)

The design optimization through modeling of a thinned bulk-PZT-based vibration energy harvester on a flexible polymeric substrate is presented. We also propose a simple foil-level fabrication process for their realization, by thinning the PZT down to 50 ?m and laminating it via dry film photoresist onto a PET substrate at low temperature (<85?°C). Two models, based on analytical and finite element modeling (FEM) methods, were developed and experimentally validated. The first, referred to as the hybrid model, is based mainly on analytical equations with the introduction of a correction factor derived from FEM simulations. The second, referred to as the numerical model, is fully based on COMSOL simulations. Both models have exhibited a very good agreement with the measured output power and resonance frequency. After their validation, a geometrical optimization through a parametric study was performed for the length, width, and thicknesses of the different layers comprising the device. As a result, an output power of 6.7 ?W at 49.8 Hz and 0.1 g, a normalized power density (NPD) of 11?683 ?W g-2 cm-3, and a figure of merit (FOM) of 227 ?W g-2 cm-3 were obtained for the optimized harvester.

Vásquez Quintero, Andrés; Besse, Nadine; Janphuang, Pattanaphong; Lockhart, Robert; Briand, Danick; de Rooij, Nico F.

2014-04-01

139

NASA Astrophysics Data System (ADS)

We propose a fine-grained stainless-steel as a promising material for a robust oscillator and investigate the dependence of frequency band width, resonance frequency, and output power on initial air gaps in electret-based vertical vibration energy harvesters. Beams of the oscillator showed a shallow side-etched depth less than 10 ?m, as well as smooth edges. The oscillator succeeded in travelling over 1-mm displacement without fracture. Also, we found that broader frequency band, as well as lower resonance frequency, can be achieved with reducing the initial air gap, whereas the output power exhibited a peak value at an optimal initial air gap. The results may be attributed to the soft spring effect induced by the stronger electrostatic force. Maximum output power density and FWHM of frequency band width of our harvester are 4.7 ?W/cm3 and 14 Hz at initial air gap 0.3 mm and acceleration 4.9 m/s2.

Asanuma, H.; Hara, M.; Oguchi, H.; Kuwano, H.

2014-11-01

140

Electromagnetic harvester for lateral vibration in rotating machines

NASA Astrophysics Data System (ADS)

Energy harvesters are devices that convert mechanical energy, usually vibration, into electrical energy that can be used to supply low power circuits (e.g. sensors). In this work, an energy harvester is designed for converting the mechanical energy of the lateral vibrations of shafts into electrical energy. For that, permanent magnets are mounted in the shaft and coils are mounted in a fixed structure. A configuration analysis is performed to find the appropriated polarization of the magnets and orientation of the coils in order to have electromagnetic induction without resisting torque on the shaft. Experimental tests are done for different electrical configurations of the coils: independent, in series and, in parallel. The results show that more electric power is induced when the coils are connected in series, and vibration reduction is more evident when the coils are connected independently.

de Araujo, Marcus Vinícius Vitoratti; Nicoletti, Rodrigo

2015-02-01

141

Multi-mechanism vibration harvester combining inductive and piezoelectric mechanisms

NASA Astrophysics Data System (ADS)

With increasing demand for wireless sensor nodes in automobile, aircraft and rail applications, the need for energy harvesters has been growing. In these applications, energy harvesters provide a more robust and inexpensive power solution than batteries. In order to enhance the power density of existing energy harvesters, a variety of multimodal energy harvesting techniques have been proposed. Multi-modal energy harvesters can be categorized as: (i) Multi-Source Energy Harvester (MSEH), (ii) Multi-Mechanism Energy Harvester (MMEH), and (iii) Single Source Multi-Mode Energy Harvester (S2M2EH). In this study, we focus on developing MMEH which combines the inductive and piezoelectric mechanisms. The multi-mechanism harvester was modeled using FEM techniques and theoretically analyzed to optimize the performance and reduce the overall shape and size similar to that of AA battery. The theoretical model combining analytical and FEM modeling techniques provides the system dynamics and output power for specific generator and cymbal geometry at various source conditions. In the proposed design, a cylindrical tube contains a magnetic levitation cavity where a center magnet oscillates through a copper coil. Piezoelectric cymbal transducers were mounted on the top and bottom sections of the cylindrical shell. In response to the external vibrations, electrical energy was harvested from the relative motion between magnet and coil through Faraday's effect and from the piezoelectric material through the direct piezoelectric effect. Experimental results validate the predictions from theoretical model and show the promise of multimodal harvester for powering wireless sensor nodes in automobile, aircraft, and rail applications.

Marin, Anthony; Priya, Shashank

2012-04-01

142

Nanocrystalline ribbons for energy harvesting applications

NASA Astrophysics Data System (ADS)

An energy harvesting device based on nanocrystalline ribbons, able to convert mechanical vibrations to electrical energy, is presented. Such an energy harvesting device having embedded wireless microsensors can provide continuous monitoring of machines or infrastructure health without using service personnel in different areas with high risks. A multilayer core based on magnetic nanocrystalline ribbons was implemented to build the coil for an electromagnetic energy harvesting device with superior characteristics (voltage and power) compared to piezoelectric or pure magnetostrictive devices. Two different configurations were realized and tested for the energy harvester: vibrating core and vibrating magnets. The highest power density achieved for our harvesters using nanocrystalline ribbons is 45 mW/cm3 at 1 g (resonant frequency 47 Hz) and seems to be among the highest reported in literature.

Chiriac, H.; Å¢ibu, M.; Lupu, N.; Skorvanek, I.; Óvári, T.-A.

2014-05-01

143

NASA Astrophysics Data System (ADS)

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.

Dudka, A.; Basset, P.; Cottone, F.; Blokhina, E.; Galayko, D.

2013-12-01

144

A Nonlinear Energy Sink with Energy Harvester

NASA Astrophysics Data System (ADS)

The transfer of energy between systems is a natural process, manifesting in many different ways. In engineering transferable energy can be considered wanted or unwanted. Specifically in mechanical systems, energy transfer can occur as unwanted vibrations, passing from a source to a receiver. In electrical systems, energy transfer can be desirable, where energy from a source may be used elsewhere. This work proposes a method to combine the two, converting unwanted mechanical energy into useable electrical energy. A nonlinear energy sink (NES) is a vibration absorber that passively localizes vibrational energy, removing mechanical energy from a primary system. Consisting of a mass-spring-damper such that the stiffness is essentially nonlinear, a NES can localize vibrational energy from a source and dissipate it through damping. Replacing the NES mass with a series of magnets surrounded by coils fixed to the primary mass, the dissipated energy can be directly converted to electrical energy. A NES with energy harvesting properties is constructed and introduced. The system parameters are identified, with the NES having an essentially cubic nonlinear stiffness. A transduction factor is quantified linking the electrical and mechanical systems. An analytic analysis is carried out studying the transient and harmonically excited response of the system. It is found that the energy harvesting does not reduce the vibrational absorption capabilities of the NES. The performance of the system in both transient and harmonically excited responses is found to be heavily influenced by input energies. The system is tested, with good match to analytic results.

Kremer, Daniel

145

A multiaxial piezoelectric energy harvester

NASA Astrophysics Data System (ADS)

An important limitation in the classical energy harvesters based on cantilever beam structure is its monodirectional sensibility. The external excitation must generate an orthogonal acceleration from the beam plane to induced flexural deformation. If the direction of the excitation deviates from this privileged direction, the harvester output power is drastically reduced. This point is obviously very restrictive in the case of an arbitrary excitation direction induced for example by human body movements or vehicles vibrations. In order to overcome this issue of the conventional resonant cantilever configuration with seismic mass, a multidirectional harvester is introduced here by the authors. The multidirectional ability relies on the exploitation of 3 degenerate structural vibration modes where each of them is induced by the corresponding component of the acceleration vector. This specific structure has been already used for 3 axis accelerometers but the approach is here totally revisited because the final functional goal is different. This paper presents the principle and the design considerations of such multidirectional piezoelectric energy harvester. A finite element model has been used for the harvester optimisation. It has been shown that the seismic mass is a relevant parameter for the modes tuning because the resonant frequency of the 1st exploited flexural mode directly depends on the mass whereas the resonance frequency of the 2nd flexural mode depends on its moment of inertia. A simplified centimetric prototype limited to a two orthogonal direction sensibility has permitted to valid the theoretical approach.

Mousselmal, H. D.; Cottinet, P. J.; Quiquerez, L.; Remaki, B.; Petit, L.

2013-04-01

146

Asynchronous phase shifted electromagnetic energy harvester Jinkyoo Parka, Soonduck Kwonb: Energy harvester, Electromagnetic transducer, Asynchronous vibration, Resonance 1. INTRODUCTION Energy harvesting systems refer to devices that capture and transform energy from the environment into elec- tricity

Stanford University

147

Synchronized charge extraction for aeroelastic energy harvesting

NASA Astrophysics Data System (ADS)

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.

Zhao, Liya; Tang, Lihua; Wu, Hao; Yang, Yaowen

2014-03-01

148

NASA Astrophysics Data System (ADS)

A novel three-dimensional (3D) electret-based micro power generator with multiple vibration modes has been developed, which is capable of converting low-level ambient kinetic energy to electrical energy. The device is based on a rotational symmetrical resonator which consists of a movable disc-shaped seismic mass suspended by three sets of spiral springs. Experimental analysis shows that the proposed generator operates at an out-of-plane direction at mode I of 66 Hz and two in-plane directions at mode II of 75 Hz and mode III of 78.5 Hz with a phase difference of about 90°. A corona localized charging method is also proposed that employs a shadow mask and multiple discharge needles for the production of micro-sized electret array. From tests conducted at an acceleration of 0.05 g, the prototype can generate a maximum power of 4.8 nW, 0.67 nW and 1.2 nW at vibration modes of I, II and III, respectively. These values correspond to the normalized power densities of 16 µW cm-3 g-2, 2.2 µW cm-3 g-2 and 4 µW cm-3 g-2, respectively. The results show that the generator can potentially offer an intriguing alternative for scavenging low-level ambient energy from 3D vibration sources.

Tao, Kai; Liu, Shuwei; Woh Lye, Sun; Miao, Jianmin; Hu, Xiao

2014-06-01

149

The physical acoustics of energy harvesting

Energy harvesting systems based on the transformation of acoustic vibrations into electrical energy are increasingly being used for niche applications due to the reduction in power consumption of modern day electronic systems. Typically these applications involve extracting energy at remote or isolated locations where local long term power is unavailable or inside sealed or rotating systems where cabling and electrical

Stewart Sherrit

2008-01-01

150

Mechanical Amplifier for Translational Kinetic Energy Harvesters

NASA Astrophysics Data System (ADS)

This paper reports the design, optimization, and test results of a mechanical amplifier coupled to an electromagnetic energy harvester to generate power from low- amplitude (±1 mm) and low-frequency (<5 Hz) vibrations in the presence of large static displacements. When coupled to a translational kinetic energy harvester, the amplifier boosts small vibration amplitudes by as much as 4x while accommodating translational displacements of more than 10x of vibration amplitudes. A complete electromagnetic energy harvester using this mechanical amplifier produces 16x improvement in output power (30 mW vs 1.9 mW without amplifier at 5 Hz), and a high power density of 170 ?W/cm3.

Shahosseini, I.; Najafi, K.

2014-11-01

151

Harvesting Raindrop Energy with Piezoelectrics: a Review

NASA Astrophysics Data System (ADS)

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.

Wong, Chin-Hong; Dahari, Zuraini; Abd Manaf, Asrulnizam; Miskam, Muhammad Azman

2015-01-01

152

Energy harvesting with piezoelectric drum transducer

Piezoelectric materials can convert ambient vibrations into electrical energy. In this letter, the capability of harvesting the electrical energy from mechanical vibrations in a dynamic environment through a piezoelectric drum transducer has been investigated. Under a prestress of 0.15 N and a cyclic stress of 0.7 N, a power of 11 mW was generated at the resonance frequency of the

Sheng Wang; Kwok Ho Lam; Cheng Liang Sun; Kin Wing Kwok; Helen Lai Wa Chan; Ming Sen Guo; Xing-Zhong Zhao

2007-01-01

153

NASA Astrophysics Data System (ADS)

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.

Leadenham, S.; Erturk, A.

2014-11-01

154

Piezoelectric monolayers as nonlinear energy harvesters.

We study the dynamics of h-BN monolayers by first performing ab-initio calculations of the deformation potential energy and then solving numerically a Langevine-type equation to explore their use in nonlinear vibration energy harvesting devices. An applied compressive strain is used to drive the system into a nonlinear bistable regime, where quasi-harmonic vibrations are combined with low-frequency swings between the minima of a double-well potential. Due to its intrinsic piezoelectric response, the nonlinear mechanical harvester naturally provides an electrical power that is readily available or can be stored by simply contacting the monolayer at its ends. Engineering the induced nonlinearity, a 20 nm2 device is predicted to harvest an electrical power of up to 0.18 pW for a noisy vibration of 5 pN. PMID:24722065

López-Suárez, Miquel; Pruneda, Miguel; Abadal, Gabriel; Rurali, Riccardo

2014-05-01

155

Piezoelectric monolayers as nonlinear energy harvesters

NASA Astrophysics Data System (ADS)

We study the dynamics of h-BN monolayers by first performing ab-initio calculations of the deformation potential energy and then solving numerically a Langevine-type equation to explore their use in nonlinear vibration energy harvesting devices. An applied compressive strain is used to drive the system into a nonlinear bistable regime, where quasi-harmonic vibrations are combined with low-frequency swings between the minima of a double-well potential. Due to its intrinsic piezoelectric response, the nonlinear mechanical harvester naturally provides an electrical power that is readily available or can be stored by simply contacting the monolayer at its ends. Engineering the induced nonlinearity, a 20 nm^{2} device is predicted to harvest an electrical power of up to 0.18 pW for a noisy vibration of 5 pN.

López-Suárez, Miquel; Pruneda, Miguel; Abadal, Gabriel; Rurali, Riccardo

2014-05-01

156

Motorcycle waste heat energy harvesting

NASA Astrophysics Data System (ADS)

Environmental concerns coupled with the depletion of fuel sources has led to research on ethanol, fuel cells, and even generating electricity from vibrations. Much of the research in these areas is stalling due to expensive or environmentally contaminating processes, however recent breakthroughs in materials and production has created a surge in research on waste heat energy harvesting devices. The thermoelectric generators (TEGs) used in waste heat energy harvesting are governed by the Thermoelectric, or Seebeck, effect, generating electricity from a temperature gradient. Some research to date has featured platforms such as heavy duty diesel trucks, model airplanes, and automobiles, attempting to either eliminate heavy batteries or the alternator. A motorcycle is another platform that possesses some very promising characteristics for waste heat energy harvesting, mainly because the exhaust pipes are exposed to significant amounts of air flow. A 1995 Kawasaki Ninja 250R was used for these trials. The module used in these experiments, the Melcor HT3-12-30, produced an average of 0.4694 W from an average temperature gradient of 48.73 °C. The mathematical model created from the Thermoelectric effect equation and the mean Seebeck coefficient displayed by the module produced an average error from the experimental data of 1.75%. Although the module proved insufficient to practically eliminate the alternator on a standard motorcycle, the temperature data gathered as well as the examination of a simple, yet accurate, model represent significant steps in the process of creating a TEG capable of doing so.

Schlichting, Alexander D.; Anton, Steven R.; Inman, Daniel J.

2008-03-01

157

Energy harvesting through wind excitation of a piezoelectric flag-like harvester

NASA Astrophysics Data System (ADS)

This study seeks to propose a novel approach to wind-based piezoelectric energy harvesting. A brief literature review of energy harvesting followed by a discussion of piezoelectric system dynamics is offered. Biomedical applications for piezoelectric energy harvesting are then presented offering a segue into fluid based energy harvesting. Fluid based energy harvesting is a relatively young subfield within piezoelectric energy harvesting, but it is increasingly pursued due to the ubiquitous nature of the excitation source as well as the strong correlation with other types of excitation. Vortex-induced vibrations (VIV), as well as vibrations induced by bluff bodies, and the effect of their shape on potential gains have been investigated. The interactions of VIVs on a flag-like membrane form the foundation for the piezoelectric energy harvester in this study. Polyvinylidene fluoride (PVDF) piezoelectric energy harvesters are chosen due to their desirable flexibility. Modeling of flag-like systems is review followed by system modeling of a PVDF piezoelectric flag. Numerical and experimental results from the PVDF flag-like piezoelectric energy harvester are generated and compared. A maximum power output of 1.5 mW is achieved with the flag-like system which is competitive when compared to power output and energy density levels of other studies. The power output of this system provides concrete evidence for the effective use of not only this type of energy harvester system model but also for the use of PVDFs in wind-based applications.

Truitt, Andrew

158

A tunable kinetic energy harvester with dynamic over range protection

NASA Astrophysics Data System (ADS)

This paper describes the development and implementation of a self-powered control system that autonomously adapts the resonant frequency of an electromagnetic vibration-based energy harvester to ambient vibration frequency. The tuning mechanism adjusts the harvester's spring stiffness by varying the axial tensile force between two permanent magnets. The system adjusts the resonant frequency of the harvester from 64 to 78 Hz, increasing the operational bandwidth of the harvester from 0.26 to 14 Hz, using a single structure. The same tuning principle is also applied to protect the harvester from over range acceleration which could cause physical damage to its structure. The closed loop control uses the phase difference between the harvester output signal and ambient vibration, measured by an accelerometer attached to the vibration source, to adjust the tuning mechanism.

Ayala-Garcia, I. N.; Zhu, D.; Tudor, M. J.; Beeby, S. P.

2010-11-01

159

The Vibration Test of Combine Harvester and the Anti-vibration Study of the Monitor

The vibration test of the 4LZ-2 combine harvester is carried out on the location of the driver room. The main causes of the mechanical vibration and the maximum value of the vibration are determined. The anti-vibration test of the grain lost monitor is made. On above basis the anti-vibration performance of the monitor is studied and the monitor is redesigned.

Dianyun Chen; Kun Li; Haitao Li; Yufang Cheng

2010-01-01

160

A nonlinear energy sink with an energy harvester: Transient responses

NASA Astrophysics Data System (ADS)

This paper investigates energy harvesting using nonlinear energy sink. First a novel apparatus is described in detail outlining how the essential nonlinearity and energy harvesting are achieved. Then the system modeling is addressed, including the equations of motion for the mechanical system and the electromechanical system, and a formula for the transduction factor. The experimental identification is conducted to determine several key parameters and relationships. Using the established models, a computer simulation is carried out to investigate the apparatuss performance under transient responses in terms of vibration absorption and energy harvesting. Finally experiments are conducted to validate the simulation results. It is shown that the system performs well, being capable of energy localization as well as broad band vibration absorption. The system is also shown to be capable of harvesting energy.

Kremer, Daniel; Liu, Kefu

2014-09-01

161

Piezoelectric Energy Harvesting Solutions

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

Caliò, Renato; Rongala, Udaya Bhaskar; Camboni, Domenico; Milazzo, Mario; Stefanini, Cesare; de Petris, Gianluca; Oddo, Calogero Maria

2014-01-01

162

Energy Harvesting By Optimized Piezo Transduction Mechanism

We report generation of electrical energy from nonlinear mechanical noises available in the ambient environment using optimized piezo transduction mechanisms. Obtaining energy from an ambient vibration has been attractive for remotely installed standalone microsystems and devices. The mechanical noises in the ambient environment can be converted to electrical energy by a piezo strip based on the principle of piezoelectric effect. In this work, we have designed and developed a standalone energy harvesting module based on piezo transduction mechanisms. Using this designed module we harvested noise energy and stored electrical energy in a capacitor. Using NI-PXI workstation with a LabVIEW programming, the output voltage of the piezo strip and voltage of the capacitor were measured and monitored. In this paper we discuss about the design, development, implementation, performance and characteristics of the energy harvesting module.

Boban, Bijo; Satheesh, U; Devaprakasam, D

2014-01-01

163

Snap-through piezoelectric energy harvesting

NASA Astrophysics Data System (ADS)

Snap-through mechanism is employed to harvest electricity from random vibration through piezoelectricity. The random excitation is assumed to be Gaussian white noise. The snap-through piezoelectric energy harvester possesses the bistability. For small-amplitude vibration in a potential well, the Ito stochastic differential equation of the electromechanical coupling system is derived from the Taylor approximation at a stable equilibrium point. The method of the moment differential equations is applied to determine the statistical moments of the displacement response and the output voltage. The effects of the system parameters on the output voltage and the output power are examined. The approximate analytical outcomes are qualitatively and quantitatively supported by the numerical simulations. For large-amplitude interwell motion, the effects of the parameters on the output voltage and the output power are numerically investigated. Nonlinearity produced by the snap-through improves energy harvesting so that the snap-through piezoelectric energy harvester can outperform the linear energy harvester in the similar size under Gaussian white noise excitations.

Jiang, Wen-An; Chen, Li-Qun

2014-09-01

164

An Equivalent Circuit Model for Electrostatic Energy Harvester utilized Energy Harvesting System

NASA Astrophysics Data System (ADS)

In this study, we report an equivalent circuit model of an electrostatic energy harvester for a SPICE circuit simulator. In order to simulate a harvesting system, the output power of the device is calculated in the simulator. The capacitance between the electrodes is obtained by FEM analysis by taking the fringing effect into account and the result is applied to a sub-circuit model for the simulator. Mechanical vibrations are converted into electricity by an equivalent circuit model of a mass-spring structure and an electrostatic energy harvester. The simulated output power and output waveform correspond with the measurement results of our electrostatic energy harvester. We also simulate the operation of a harvesting system connected with a power management IC.

Minami, K.; Fujita, T.; Sonoda, K.; Miwatani, N.; Kanda, K.; Maenaka, K.

2014-11-01

165

Energy Harvesting Diamond Channel with Energy Cooperation

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

Ulukus, Sennur

166

Energy Harvesting Communications with Continuous Energy Arrivals

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

Yener, Aylin

167

Enhanced energy harvesting in commercial ferroelectric materials

NASA Astrophysics Data System (ADS)

Ferroelectric materials are used in a number of applications ranging from simple sensors and actuators to ferroelectric random access memories (FRAMs), transducers, health monitoring system and microelectronics. The multiphysical coupling ability possessed by these materials has been established to be useful for energy harvesting applications. However, conventional energy harvesting techniques employing ferroelectric materials possess low energy density. This has prevented the successful commercialization of ferroelectric based energy harvesting systems. In this context, the present study aims at proposing a novel approach for enhanced energy harvesting using commercially available ferroelectric materials. This technique was simulated to be used for two commercially available piezoelectric materials namely PKI-552 and APCI-840, soft and hard lead-zirconate-titanate (PZT) pervoskite ceramics, respectively. It was observed that a maximum energy density of 348 kJm-3cycle-1 can be obtained for cycle parameters of (0-1 ton compressive stress and 1-25 kV.cm-1 electric field) using APCI-840. The reported energy density is several hundred times larger than the maximum energy density reported in the literature for vibration harvesting systems.

Patel, Satyanarayan; Chauhan, Aditya; Vaish, Rahul

2014-04-01

168

Delay-Tolerant Data Gathering in Energy Harvesting Sensor Networks With a Mobile Sink

to harvest ambient energy such as solar energy, wind energy, vibration energy, and so on, from their surDelay-Tolerant Data Gathering in Energy Harvesting Sensor Networks With a Mobile Sink Xiaojiang Ren collection in an energy harvesting sensor network with a mobile sink, where a mobile sink travels along

Liang, Weifa

169

Power flow analysis for amplifier design and energy harvesting

Power flow analysis for amplifier design and energy harvesting Nikola Vujica, Donald J. Leoa flow, state-space control, power harvesting, optimization 1. INTRODUCTION Active material systems on active and combined active and passive (hybrid) vibration suppression systems have shown a good

Lindner, Douglas K.

170

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 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 quantify its quantum advantage using thermodynamic measures of performance. We also demonstrate the principle's applicability for realistic biological structures.

Killoran, Nathan; Plenio, Martin B

2014-01-01

171

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 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 quantify its quantum advantage using thermodynamic measures of performance. We also demonstrate the principle's applicability for realistic biological structures.

Nathan Killoran; Susana F. Huelga; Martin B. Plenio

2014-12-12

172

Study on Vibration of Logging Harvester in Forest Land

The logging harvester is made up of a walking mechanism, a mechanical arm, a felling head and a driving control system, which can do the works of felling, limbing, measuring and bucking. Because the ground surface of the forest land is very rough, the vibration should be studied when it is going in the forest land in order to prevent

Xu Wenxuan; Lu Huaimin; Guo Xiuli

2010-01-01

173

The case for energy harvesting on wildlife in flight

NASA Astrophysics Data System (ADS)

The confluence of advancements in microelectronic components and vibrational energy harvesting has opened the possibility of remote sensor units powered solely from the motion of their hosts. There are numerous applications of such systems, including the development of modern wildlife tracking/data-logging devices. These ‘bio-logging’ devices are typically mass-constrained because they must be carried by an animal. Thus, they have historically traded scientific capability for operational longevity due to restrictions on battery size. Recently, the precipitous decrease in the power requirements of microelectronics has been accompanied by advancements in the area of piezoelectric vibrational energy harvesting. These energy harvesting devices are now capable of powering the type of microelectronic circuits used in bio-logging devices. In this paper we consider the feasibility of employing these vibrational energy harvesters on flying vertebrates for the purpose of powering a bio-logging device. We show that the excess energy available from birds and bats could be harvested without adversely affecting their overall energy budget. We then present acceleration measurements taken on flying birds in a flight tunnel to understand modulation of flapping frequency during steady flight. Finally, we use a recently developed method of estimating the maximum power output from a piezoelectric energy harvester to determine the amount of power that could be practically harvested from a flying bird. The results of this analysis show that the average power output of a piezoelectric energy harvester mounted to a bird or bat could produce more than enough power to run a bio-logging device. We compare the power harvesting capabilities to the energy requirements of an example system and conclude that vibrational energy harvesting on flying birds and bats is viable and warrants further study, including testing.

Shafer, Michael W.; MacCurdy, Robert; Shipley, J. Ryan; Winkler, David; Guglielmo, Christopher G.; Garcia, Ephrahim

2015-02-01

174

Multi-source energy harvesting for wireless SHM systems

NASA Astrophysics Data System (ADS)

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.

Choi, Mijin; Farinholt, Kevin M.; Anton, Steven; Lee, Jung-Ryul; Park, Gyuhae

2013-03-01

175

Piezoelectric cantilevers energy harvesting in MEMS technique

NASA Astrophysics Data System (ADS)

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.

Shang, Yingqi; Qiu, Chengjun; Liu, Hongmei; Chen, Xiaojie; Qu, Wei; Dou, Yanwei

2011-11-01

176

Piezoelectric cantilevers energy harvesting in MEMS technique

NASA Astrophysics Data System (ADS)

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.

Shang, Yingqi; Qiu, Chengjun; Liu, Hongmei; Chen, Xiaojie; Qu, Wei; Dou, Yanwei

2012-04-01

177

Energy harvesting for self-powered aerostructure actuation

NASA Astrophysics Data System (ADS)

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.

Bryant, Matthew; Pizzonia, Matthew; Mehallow, Michael; Garcia, Ephrahim

2014-04-01

178

Plucked piezoelectric bimorphs for energy harvesting applications

NASA Astrophysics Data System (ADS)

The modern drive towards mobility and wireless devices is motivating intense research in energy harvesting (EH) technologies. In an effort to reduce the battery burden of people, we are investigating a novel piezoelectric wearable energy harvester. As piezoelectric EH is significantly more effective at high frequencies, in opposition to the characteristically low-frequency human activities, we propose the use of an up-conversion strategy analogous to the pizzicato musical technique. In order to guide the design of such harvester, we have modelled with Finite Elements (FE) the response and power generation of a piezoelectric bimorph while it is "plucked", i.e. deflected, then released and permitted to vibrate freely. An experimental rig has been devised and set up to reproduce the action of the bimorph in the harvester. Measurements of the voltage output and the energy dissipated across a series resistor are reported and compared with the FE predictions. As the novel harvester will feature a number of bimorphs, each plucked tens of times per step, we predict a total power output of several mW, with imperceptible effect on the wearer's gait.

Pozzi, Michele; Zhu, Meiling

2011-06-01

179

Electrostatic Energy Harvesters Based on Green Materials .

??This thesis presents the analysis and modelling of electrostatic energy harvesters based on renewable green materials. Conventional and new regenerative electrostatic energy harvesters are designed… (more)

Li, Yin

2013-01-01

180

Tree-inspired piezoelectric energy harvesting

NASA Astrophysics Data System (ADS)

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.

Hobbs, William B.; Hu, David L.

2012-01-01

181

Passively Self-Tuning Piezoelectric Energy Harvesting System

NASA Astrophysics Data System (ADS)

Real world systems that are candidates for vibrational energy harvesting rarely vibrate at a single frequency, nor are these frequencies constant over time. This necessitates that vibration harvesters operate over a wide bandwidth or tune their resonance. Most tunable devices require additional energy or active control to achieve resonance over various frequencies. This work presents a passively self-tuning energy harvester that autonomously adapts its resonant frequency to the input without requiring additional energy. The system consists of a clamped- clamped beam, a movable proof mass, and a piezoelectric patch bonded to the underside of the beam. It demonstrated an open-circuit voltage output of 668 mVrms at 160Hz, 0.65g input excitation. Discrepancies between displacement and voltage magnification factors upon tuning at higher frequencies are discussed, as well as instabilities of the system and sensitivity to proof mass characteristics.

Gregg, C. G.; Pillatsch, P.; Wright, P. K.

2014-11-01

182

To harvest energy from mechanical vibration with piezoelectric materials, different installations might be adopted according to the vibration conditions of the substrate structures. Surface mount (deformation preferred) and base excitation (movement preferred) are two of the commonly utilized installations. These configurations can be modeled as a general piezoelectric energy harvesting (PEH) device under displacement and force excitations, respectively. Comparison on

Junrui Liang; Wei-Hsin Liao

2010-01-01

183

Design method for piezoelectric bending generators in energy harvesting systems

The increased demand for mobile systems using low-power electronics leads to a need for new power sources. Using batteries as power source may be inapplicable in distributed systems like wireless sensor networks because the batteries have to be exchanged frequently. Energy Harvesting systems are one possible energy source for such systems exploiting environmental energy like mechanical vibrations. One good solution

Björn Richter; Jens Twiefel; Thomas Sattel; Jörg Wallaschek

2007-01-01

184

Micro-fabricated silicon spiral spring based electromagnetic energy harvester

NASA Astrophysics Data System (ADS)

In this study, an electromagnetic energy harvester using a bulk micromachined silicon spiral spring and a polydimethylsiloxane (PDMS) packaging technique was fabricated and characterized to generate electrical energy from ultra-low ambient vibrations under at vibration accelerations 0.3g. The proposed energy harvester was comprised of a highly-miniaturized neodymium-ironboron (NdFeB) magnet, a silicon spiral spring, a multi-turn copper coil, and a PDMS housing in order to improve its electrical output power and reduce its size/volume. When an external vibration directly moves the mounted magnet as a seismic mass at the center of the spiral spring, the mechanical energy of the moving mass was transformed into electrical energy through the 183 turns of the solenoid copper coil. Silicon spiral springs were used to generate a high electrical output power by maximizing the deflection of the movable mass in response to low-level vibrations. The fabricated energy harvester exhibited a resonant frequency of 36 Hz and an optimal load resistance of 99 ?. It generated an output power of 29.02 µW and load voltage of 107.3 mV at a vibration acceleration of 0.3g. It also exhibited a power density and normalized power density of 48.37 µW·cm-3 and 537.41 µW·cm-3·g-2, respectively. The total volume of the fabricated energy harvester was 1 cm × 1 cm × 0.6 cm (height).

Bang, Dong Hyun; Park, Jae Yeong

2013-06-01

185

Performance of a piezoelectric energy harvester driven by air flow

NASA Astrophysics Data System (ADS)

A turbulent wind source for possible energy harvesting is considered. To increase the amplitude of vibration, we apply a magnetopiezoelastic oscillator having a double well Duffing potential. The output voltage response of the system for different level of wind excitations is analyzed. The energy harvesting appeared to be the most efficient for the conditions close to the stochastic resonance region where the potential barrier was overcame.

Kitio Kwuimy, C. A.; Litak, G.; Borowiec, M.; Nataraj, C.

2012-01-01

186

Energy harvesting using RF MEMS

This paper presents a novel technology which provides a promising solution for designing self-powered microsystems. Micro-Electro Mechanical System (MEMS) energy harvesting is an emerging alternative for scavenging energy from natural sources. It has extensive potential in wireless sensor applications to provide a natural energy source that is essentially inexhaustible. It is an increasingly attractive alternative to costly batteries. This essentially

Yunhan Huang; Ravi Doraiswami; Michael Osterman; Michael Pecht

2010-01-01

187

A Hip Implant Energy Harvester

NASA Astrophysics Data System (ADS)

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?.

Pancharoen, K.; Zhu, D.; Beeby, S. P.

2014-11-01

188

An electrostatic CMOS/BiCMOS Lithium ion vibration-based harvester-charger IC

NASA Astrophysics Data System (ADS)

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.

Torres, Erick Omar

189

An innovative tri-directional broadband piezoelectric energy harvester

NASA Astrophysics Data System (ADS)

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.

Su, Wei-Jiun; Zu, Jean

2013-11-01

190

Flow energy piezoelectric bimorph nozzle harvester

NASA Astrophysics Data System (ADS)

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.

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

191

MEMS Batch Fabrication of the Bipolar Micro Magnet Array for Electromagnetic Vibration Harvester

NASA Astrophysics Data System (ADS)

This article introduces a MEMS batch fabrication process of micro magnet array with bipolar magnetic pole for an electromagnetic vibration energy harvester. In order to obtain the large electromotive force from large magnetic flux density change, we established the fine patterned alternating magnetized bipolar magnetic structure. The batch fabrication process of bipolar magnet array is composed of two wafers processing with S-pole and N-pole magnetization and bonding process. By the prototype fabrication of bipolar magnet with the 200 ?m SN-interval, we showed the usability of the batch fabrication process of the bipolar magnet array. In addition, we estimated the generated power of energy harvester with a bipolar magnet array. Compared to a harvester with monopolar magnet array, we showed the good result for bipolar one.

Yamaguchi, K.; Fujita, T.; Tanaka, Y.; Takehira, N.; Sonoda, K.; Kanda, K.; Maenaka, K.

2014-11-01

192

Energy harvesting with coupled magnetostrictive resonators

NASA Astrophysics Data System (ADS)

We report the investigation of an energy harvesting system composed of coupled resonators with the magnetostrictive material Galfenol (FeGa). A coupled system of meso-scale (1-10 cm) cantilever beams for harvesting vibration energy is described for powering and aiding the performance of low-power wireless sensor nodes. Galfenol is chosen in this work for its durability, compared to the brittleness often encountered with piezoelectric materials, and high magnetomechanical coupling. A lumped model, which captures both the mechanical and electrical behavior of the individual transducers, is first developed. The values of the lumped element parameters are then derived empirically from fabricated beams in order to compare the model to experimental measurements. The governing equations of the coupled system lead to a system of differential equations with all-to-all coupling between transducers. An analysis of the system equations reveals different patterns of collective oscillations. Among the many different patterns, a synchronous state appears to yield the maximum energy that can be harvested by the system. Experiments on coupled system shows that the coupled system exhibits synchronization and an increment in the output power. Discussion of the required power converters is also included.

Naik, Suketu; Phipps, Alex; In, Visarath; Cavaroc, Peyton; Matus-Vargas, Antonio; Palacios, Antonio; Gonzalez-Hernandez, H. G.

2014-03-01

193

Flexible and Robust Multilayer Micro-Vibrational Harvesters for High Acceleration Environments

NASA Astrophysics Data System (ADS)

This paper presents the fabrication and characterization of multilayer PVDF resonant micro-vibrational energy harvesters designed to withstand environments in which high levels of acceleration are present. The multilayer cantilevers are fabricated by combining two folded PVDF stacks into a multilayered, bimorph structure. This acts to increase the overall capacitance of the harvester, a problem that plaques PVDF cantilevers as a result of its low dielectric constant. Moderate powers (7 ?W) are produced from the cantilevers even at high acceleration levels (20 g) due to the limited piezoelectric coefficient of PVDF; however, as a result of the high tensile strength and low elastic modulus of PVDF, the cantilevers are able to survive extremely high accelerations (> 4000 g) without breakage - a critical problem for harvesters based on brittle piezoelectric materials and substrates.

Lockhart, R.; Dauksevicius, R.; Vasquez Quintero, A.; Janphuang, P.; Briand, D.; de Rooij, N. F.

2013-12-01

194

Scaling prospects in mechanical energy harvesting with piezo nanowires

NASA Astrophysics Data System (ADS)

The combination of 3D processing technologies, low power circuits and new materials integration makes it conceivable to build autonomous integrated systems, which would harvest their energy from the environment. In this paper, we focus on mechanical energy harvesting and discuss its scaling prospects toward the use of piezoelectric nanostructures, able to be integrated in a CMOS environment. It is shown that direct scaling of present MEMS-based methodologies would be beneficial for high-frequency applications only. For the range of applications which is presently foreseen, a different approach is needed, based on energy harvesting from direct real-time deformation instead of energy harvesting from vibration modes at or close to resonance. We discuss the prospects of such an approach based on simple scaling rules Contribution to the Topical Issue “International Semiconductor Conference Dresden-Grenoble - ISCDG 2012”, Edited by Gérard Ghibaudo, Francis Balestra and Simon Deleonibus.

Ardila, Gustavo; Hinchet, Ronan; Mouis, Mireille; Montès, Laurent

2013-07-01

195

Experimental study of a multi-impact energy harvester under low frequency excitations

NASA Astrophysics Data System (ADS)

The multi-impact energy harvester of the present study is a retrofitted piezoelectric based energy harvesting device that is designed especially for low frequency excitations. It consists of a spring-mass system and two piezoelectric cantilevers. By utilizing a series of impacts between the cantilevers and the moving mass, ambient vibrations of low frequencies can be up-converted into high frequency vibrations on the piezoelectric cantilevers and therefore generate usable electric energy. To examine the performance of the multi-impact harvester, a model is designed and machined for the experimental study. Sinusoidal vibrations and simulated bridge vibrations are used as the excitations for the harvester. A traditional cantilever piezoelectric harvester is also made for a performance comparison.

Zhang, Ye; Cai, C. S.; Zhang, Wei

2014-05-01

196

Energy Harvesting Broadcast Channel with Inefficient Energy Storage

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

Yener, Aylin

197

Enhanced PVDF film for multi energy harvesting

NASA Astrophysics Data System (ADS)

PVDF is a very important piezoelectric polymer material which has a promising range of applications in a variety of fields such as acoustic sensors and transducers, electrical switches, medical instrumentation, artificial sensitive skin in robotics, automotive detection on roads, nondestructive testing, structural health monitoring and as a biocampatible material. In this research cantilever based multi energy harvester was developed to maximize the power output of PVDF sensor. Nano mixture containing ferrofluid (FF) and ZnO nano particles were used to enhance the piezoelectric output of the sensor. The samples were tested under different energy conditions to observe the behavior of nano coated PVDF film under multi energy conditions. Composition of the ZnO and FF nano particles were changed by weight, in order to achieve the optimal composition of the nano mixture. Light energy, vibration energy, combined effect of light and vibration energy, and magnetic effect were used to explore the behavior of the sensor. The sensor with 60% ZnO and 40% FF achieved a maximum power output of 10.7 microwatts when it is under the combined effect of light and vibration energy. Which is nearly 16 times more power output than PVDF sensor. When the magnetic effect is considered the sensor with 100% FF showed the highest power output of 11.2 microwatts which is nearly 17 times more power output than pure PVDF. The effective piezoelctric volume of the sensor was 0.017 cm3. In order to explore the effect of magnetic flux, cone patterns were created on the sensor by means of a external magnetic field. Stability of the cones generated on the sensor played a major role in generated power output.

Karunarathna, Ranmunige Nadeeka

198

Passively-switched energy harvester for increased operational range

NASA Astrophysics Data System (ADS)

This paper presents modeling and experimental validation of a new type of vibrational energy harvester that passively switches between two dynamical modes of operation to expand the range of driving frequencies and accelerations over which the harvester effectively extracts power. In both modes, a driving beam with a low resonant frequency couples into ambient vibrations and transfers their energy to a generating beam that has a higher resonant frequency. The generating beam converts the mechanical power into electrical power. In coupled-motion mode, the driving beam bounces off the generating beam. In plucked mode, the driving beam deflects the generating beam until the driving beam passes from above the generating beam to below it or vice versa. Analytical system models are implemented numerically in the time domain for driving frequencies of 3 Hz to 27 Hz and accelerations from 0.1 g to 2.6 g, and both system dynamics and output power are predicted. A corresponding switched-dynamics harvester is tested experimentally, and its voltage, power, and dynamics are recorded. In both models and experiments, coupled-motion harvesting is observed at lower accelerations, whereas plucked harvesting and/or mixed mode harvesting are observed at higher accelerations. As expected, plucked harvesting outputs greater power than coupled-motion harvesting in both simulations and experiments. The predicted (1.8 mW) and measured (1.56 mW) maximum average power levels are similar under measured conditions at 0.5 g. When the system switches to dynamics that are characteristic of higher frequencies, the difference between predicted and measured power levels is more pronounced due to non-ideal mechanical interaction between the beams’ tips. Despite the beams’ non-ideal interactions, switched-dynamics operation increases the harvester’s operating range.

Liu, Tian; St. Pierre, Ryan; Livermore, Carol

2014-09-01

199

Nonlinear mechanism in MEMS devices for energy harvesting applications

NASA Astrophysics Data System (ADS)

This paper reports a novel bistable microelectromechanical system for energy harvesting applications. In particular, we focus here on methodologies and devices for recovering energy from mechanical vibrations. A common energy harvesting approach is based on vibrating mechanical bodies that collect energy through the adoption of self-generating materials. This family of systems has a linear mass-spring damping behaviour and shows good performance around its natural frequency. However, it is not generally suitable for energy recovery in a wide spectrum of frequencies as expected in the vast majority of cases when ambient vibrations assume different forms and the energy is distributed over a wide range of frequencies. Furthermore, whenever the vibrations have a low frequency content the implementation of an integrated energy harvesting device is challenging; in fact large masses and devices would be needed to obtain resonances at low frequencies. Here, the idea is to consider the nonlinear behaviour of a bistable system to enhance device performances in terms of response to external vibrations. The switching mechanism is based on a structure that oscillates around one of the two stable states when the stimulus is not large enough to switch to the other stable state and that moves around the other stable state as soon as it is excited over the threshold. A response improvement can be demonstrated compared to the classical linear approach. Indeed, both a wider spectrum will appear as a consequence of the nonlinear term and a significant amount of energy is collected at low frequencies. In this paper the bistable working principle is first described and analytically modelled, and then a numerical study based on stochastic differential equations (SDE) is realized to evaluate the behaviour of a MEMS device. A micromachined SOI prototype has been realized and a measurement campaign validated the nonlinear mechanism. As expected, the study shows that the nonlinear system exhibits a low pass filter behaviour suitable for harvesting ambient energy at low frequency.

Andò, B.; Baglio, S.; Trigona, C.; Dumas, N.; Latorre, L.; Nouet, P.

2010-12-01

200

applications of electrets such as acoustic/mechanical transducers and air filter have been proposed [14 for large output power. Figure 2 shows power spectra of vibration acceleration in a car cabin. Since high Figure 1. Vibration-driven power generator. Figure 2. Power spectra of vibration in a car cabin. -180

Kasagi, Nobuhide

201

PIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGY

PIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGY PIEZOELECTRIC POWER SCAVENGING OFPIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGYMECHANICAL VIBRATION ENERGY CE 511- Structural

Ervin, Elizabeth K.

202

Degradation of Piezoelectric Materials for Energy Harvesting Applications

NASA Astrophysics Data System (ADS)

The purpose of energy harvesting is to provide long term alternatives to replaceable batteries across a number of applications. Piezoelectric vibration harvesting provides advantages over other transduction methods due to the ability to generate large voltages even on a small scale. However, the operation in energy harvesting is different from typical sensors or actuators. The applied stress is often at the material limit in order to generate the maximum power output. Under these conditions, the degradation of the materials becomes an important factor for long term deployment. In this work bimorph piezoelectric beams were sub jected to lifetime testing through electromagnetic tip actuation for a large number of cycles. The results of two measurement series at different amplitudes are discussed. The dominant effect observed was a shift in mechanical resonance frequencies of the beams which could be very detrimental to resonant harvesters.

Pillatsch, P.; Shashoua, N.; Holmes, A. S.; Yeatman, E. M.; Wright, P. K.

2014-11-01

203

Conceptual design of rotary magnetostrictive energy harvester

NASA Astrophysics Data System (ADS)

This paper presents the conceptual design of a rotary magnetostrictive energy harvester (RMEH), which consists of one coil-wound Galfenol cantilever, with two PMs adhered onto the each end, and one permanent magnet (PM) array sandwiched between two wheels. Modeling and simulation are used to validate the concept. The proof-of-concept RMEH is fabricated by using the simulation results, and subjected to the experimental characterization. The experimental setup for the simulated characterization uses the motor-driven PM array to induce a forced vibration. It can be concluded that the theoretical prediction on the induced voltage agrees well with the experimental results and that induced voltage increases with rpm and with number of PMs. Future work includes optimization of RMEH performance via PM array configuration and development of prototype.

Park, Young-Woo; Kang, Han-Sam; Wereley, Norman M.

2014-05-01

204

Energy harvesting from low frequency applications using piezoelectric materials

NASA Astrophysics Data System (ADS)

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.

Li, Huidong; Tian, Chuan; Deng, Z. Daniel

2014-12-01

205

Energy Harvesting Sensor Nodes: Survey and Implications

Sensor networks with battery-powered nodes can seldom simultaneously meet the design goals of lifetime, cost, sensing reliability and sensing and transmission coverage. Energy-harvesting, convert- ing ambient energy to electrical energy, has emerged as an alternative to power sensor nodes. By exploiting recharge opportunities and tuning performance parameters based on current and expected energy levels, energy harvesting sensor nodes have the

Sujesha Sudevalayam; Purushottam Kulkarni

2011-01-01

206

Energy Harvesting for Aerospace Structural Health Monitoring Systems

NASA Astrophysics Data System (ADS)

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.

Pearson, M. R.; Eaton, M. J.; Pullin, R.; Featherston, C. A.; Holford, K. M.

2012-08-01

207

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

Michele Pozzi; Meiling Zhu

2011-01-01

208

Piezoelectric energy harvesting using a series synchronized switch technique

NASA Astrophysics Data System (ADS)

An alternative switching technique for piezoelectric energy harvesting is presented. The energy harvester based on piezoelectric elements is a promising method to scavenge ambient energy. Several non-linear techniques such as SSHI have been implemented to improve the global harvested energy. However, these techniques are sensitive to load and should be tuned to obtain optimal power output. This technique, called Series Synchronized Switch Harvesting (S3H), has both the advantage of easy implementation and independence of the harvested power with the load impedance. The harvesting circuit simply consists of a switch in series with the piezoelement and the load. The switch is nearly always open and is triggered-on each time the piezoelectric voltage reaches an extremum. It is opened back after an arbitrary on-time t0. The energy scavenging process happens when switch is closed. Based on linear motion assumption, the harvester structure is modeled as a "Mass-Spring-Damper" system. The analysis of S3H technique is considered with harmonic excitation. An analytical model of S3H is presented and discussed. The main advantage of this approach compared with the usual standard technique is that the extracted power is independent of the load within a wide range of load impedance, and that the useful impedance range is simply related to the defined switch on-time. For constant displacement excitation condition, the optimal power output is more than twice the power extracted by the standard technique as long as the on-time interval is small comparatively with the vibration period. For constant force excitation, an optimal on-time can be defined resulting in an optimally wide load bandwidth. Keywords: piezoelectric; energy harvesting; non-linear harvesting techniques; switching techniques.

Li, Yang; Lallart, Mickaël.; Richard, Claude

2014-04-01

209

This work presents an integration approach towards manufacturing a MEMS piezoelectric vibration energy harvester and an electrochemical capacitor on the same substrate. Vibration energy harvesters have been fabricated to resonate at low frequencies, matching ambient vibrations found abundantly in buildings. For cost-effective resonance tuning, a direct write dispenser printer can be used to print additional mass at the tips of

Lindsay M. Miller; Paul K. Wright; Christine C. Ho; James W. Evans; Padraic C. Shafer; R. Ramesh

2009-01-01

210

Dual-phase self-biased magnetoelectric energy harvester

NASA Astrophysics Data System (ADS)

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.

Zhou, Yuan; Apo, Daniel J.; Priya, Shashank

2013-11-01

211

NASA Astrophysics Data System (ADS)

Power harvesting techniques that convert vibration energy into electrical energy through piezoelectric transducers show strong potential for powering smart wireless sensor devices in applications of structural health monitoring. This paper presents an analytical model of the dynamic behavior of an electromechanical piezoelectric bimorph cantilever harvester connected with an AC-DC circuit based on the Euler-Bernoulli beam theory and Hamiltonian theorem. A new cantilevered piezoelectric bimorph structure is proposed in which the plug-type connection between support layer and tip-mass ensures that the gravity center of the tip-mass is collinear with the gravity center of the beam so that the brittle fracture of piezoelectric layers can also be avoided while vibrating with large amplitude. The tip-mass is equated by the inertial force and inertial moment acting at the end of the piezoelectric bimorph beam based on D'Alembert's principle. An AC-DC converting circuit soldered with the piezoelectric elements is also taken into account. A completely new analytic expression of the global behavior of the electromechanical piezoelectric bimorph harvesting system with AC-DC circuit under input base transverse excitation is derived. Moreover, an experimental energy harvester is fabricated and the theoretical analysis and experimental results of the piezoelectric harvester under the input base transverse displacement excitation are validated by using measurements of the absolute tip displacement, electric voltage response, electric current response and electric power harvesting.

Wang, Hongjin; Meng, Qingfeng

2013-03-01

212

Mechanical vibration to electrical energy converter

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.

Kellogg, Rick Allen (Tijeras, NM); Brotz, Jay Kristoffer (Albuquerque, NM)

2009-03-03

213

Energy Harvesting Communications with Hybrid Energy Storage and Processing Cost

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

Ulukus, Sennur

214

Investigations of biomimetic light energy harvesting pigments

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.

Van Patten, P.G.; Donohoe, R.J. [Los Alamos National Lab., NM (United States); Lindsey, J.S. [North Carolina State Univ., Raleigh, NC (United States); Bocian, D.F. [Univ. of California, Riverside, CA (United States)

1998-12-01

215

The Energy Harvesting Multiple Access Channel with Energy Storage Losses

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

Yener, Aylin

216

1 A 0.7-Âµm BiCMOS Electrostatic Energy-Harvesting System IC Erick O. Torres, Graduate Student.7-Âµm BiCMOS vibration-supplied electrostatic energy-harvesting system IC produces usable energy. The IC. Index Terms: Electrostatic energy harvester IC, vibration, low energy, microsensor, microsystem I

Rincon-Mora, Gabriel A.

217

Efficiency of harvesting energy from colored noise by linear oscillators

NASA Astrophysics Data System (ADS)

We investigate the performance of a linear electromechanical oscillator as an energy harvester of finite-bandwidth random vibrations. We derive exact analytical expressions for the net electrical power and the efficiency of the conversion of the power supplied by the noise into electrical power for arbitrary colored noise. We apply our results to the important case of exponentially correlated noise and discuss the tuning of parameters to achieve good performance of the device.

Méndez, Vicenç; Campos, Daniel; Horsthemke, Werner

2013-08-01

218

Plucked piezoelectric bimorphs for energy harvesting applications

The modern drive towards mobility and wireless devices is motivating intense research in energy harvesting (EH) technologies. In an effort to reduce the battery burden of people, we are investigating a novel piezoelectric wearable energy harvester. As piezoelectric EH is significantly more effective at high frequencies, in opposition to the characteristically low-frequency human activities, we propose the use of an

Michele Pozzi; Meiling Zhu

2011-01-01

219

Nonperturbative vibrational energy relaxation effects on vibrational line shapes

Nonperturbative vibrational energy relaxation effects on vibrational line shapes Shilong Yang quantum dynamics of solutes in a condensed phase is proposed to calculate linear and nonlinear vibrational rate are derived in Appendix A. The vibrational energy relaxation VER rate is negligible for slow

Cao, Jianshu

220

Wide-bandwidth piezoelectric energy harvester with polymeric structure

NASA Astrophysics Data System (ADS)

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.

Rezaeisaray, Mehdi; El Gowini, Mohamed; Sameoto, Dan; Raboud, Don; Moussa, Walied

2015-01-01

221

Design and development of a novel bi-directional piezoelectric energy harvester

NASA Astrophysics Data System (ADS)

In this paper, a novel bi-directional piezoelectric energy harvester which can harvest vibration energy bi-directionally is introduced and investigated theoretically and experimentally. The proposed harvester is composed of two sub-systems: a main beam to generate electricity and a spring-mass oscillator to trigger the vibration of the main beam from an additional direction by using magnets to couple the two sub-systems. The theoretical model is built on the basis of the Euler-Bernoulli beam theory and the magnetic charge model. A prototype is fabricated to test the performance of the harvester experimentally. Linear upward and downward frequency sweeps are used to obtain the frequency responses. The experimental results show good agreement with the theoretical model under frequency sweeps. A comparison with a beam-beam bi-directional piezoelectric energy harvester is also performed experimentally. Although both bi-directional piezoelectric energy harvesters exhibit the capability of harvesting vibration energy in two orthogonal directions, the beam-spring energy harvester shows a more consistent performance in both directions as regards the bandwidth and amplitude of the frequency responses.

Su, Wei-Jiun; Zu, Jean W.

2014-09-01

222

Vibration-assisted resonance in photosynthetic excitation-energy transfer

NASA Astrophysics Data System (ADS)

Understanding how the effectiveness of natural photosynthetic energy-harvesting systems arises from the interplay between quantum coherence and environmental noise represents a significant challenge for quantum theory. Recently it has begun to be appreciated that discrete molecular vibrational modes may play an important role in the dynamics of such systems. Here we present a microscopic mechanism by which intramolecular vibrations may be able to contribute to the efficiency and directionality of energy transfer. Excited vibrational states create resonant pathways through the system, supporting fast and efficient energy transport. Vibrational damping together with the natural downhill arrangement of molecular energy levels gives intrinsic directionality to the energy flow. Analytical and numerical results demonstrate a significant enhancement of the efficiency and directionality of energy transport that can be directly related to the existence of resonances between vibrational and excitonic levels.

Irish, E. K.; Gómez-Bombarelli, R.; Lovett, B. W.

2014-07-01

223

Micro Electret Energy Harvesting Device with Analogue Impedance Conversion Circuit

Micro Electret Energy Harvesting Device with Analogue Impedance Conversion Circuit Yuji Suzuki1 using a low-power-consumption impedance conversion circuit. Key words: Energy harvesting, Electret, CYTOP, Parylene spring, Impedance conversion 1. INTRODUCTION Energy harvesting from environmental

Kasagi, Nobuhide

224

Flight Test Results of a Thermoelectric Energy Harvester for Aircraft

NASA Astrophysics Data System (ADS)

The idea of thermoelectric energy harvesting for low-power wireless sensor systems in aircraft and its practical implementation was recently published. The concept of using a thermoelectric generator (TEG) attached to the aircraft inner hull and a thermal storage device to create an artificial temperature gradient at the TEG during take-off and landing from the temperature changes of the fuselage has passed initial tests and is now subject to flight testing. This work presents preflight test results, e.g., vibration and temperature testing of the harvesters, the practical installation of two harvesting devices inside a test plane, and the first test flight results. Several flight cycles with different flight profiles, flight lengths, and outside temperatures have been performed. Although the influence of different flight profiles on the energy output of the harvester can be clearly observed, the results are in good agreement with expectations from numerical simulations with boundary conditions evaluated from initial climate chamber experiments. In addition, the flight test demonstrates that reliable operation of thermoelectric energy harvesting in harsh aircraft environments seems to be feasible, therefore paving the way for realization of energy-autonomous, wireless sensor networks.

Samson, D.; Kluge, M.; Fuss, T.; Schmid, U.; Becker, Th.

2012-06-01

225

Broadband energy harvesting using acoustic black hole structural tailoring

NASA Astrophysics Data System (ADS)

This paper explores the concept of an acoustic black hole (ABH) as a main design framework for performing dynamic structural tailoring of mechanical systems for vibration energy harvesting applications. The ABH is an integral feature embedded in the host structure that allows for a smooth reduction of the phase velocity, theoretically approaching zero, while minimizing the reflected energy. This mechanism results in structural areas with high energy density that can be effectively exploited to develop enhanced vibration-based energy harvesting. Fully coupled electro-mechanical models of an ABH tapered structure with surface mounted piezo-transducers are developed to numerically simulate the response of the system to both steady state and transient excitations. The design performances are numerically evaluated using structural intensity data as well as the instantaneous voltage/power and energy output produced by the piezo-transducer network. Results show that the dynamically tailored structural design enables a drastic increase in the harvested energy as compared to traditional structures, both under steady state and transient excitation conditions.

Zhao, Liuxian; Conlon, Stephen C.; Semperlotti, Fabio

2014-06-01

226

Hybrid piezoelectric energy harvesting transducer system

NASA Technical Reports Server (NTRS)

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.

Xu, Tian-Bing (Inventor); Jiang, Xiaoning (Inventor); Su, Ji (Inventor); Rehrig, Paul W. (Inventor); Hackenberger, Wesley S. (Inventor)

2008-01-01

227

Damping as a result of piezoelectric energy harvesting

NASA Astrophysics Data System (ADS)

Systems that harvest or scavenge energy from their environments are of considerable interest for use in remote power supplies. A class of such systems exploits the motion or deformation associated with vibration, converting the mechanical energy to electrical, and storing it for later use; some of these systems use piezoelectric materials for the direct conversion of strain energy to electrical energy. The removal of mechanical energy from a vibrating structure necessarily results in damping. This research addresses the damping associated with a piezoelectric energy harvesting system that consists of a full-bridge rectifier, a filter capacitor, a switching DC-DC step-down converter, and a battery. Under conditions of harmonic forcing, the effective modal loss factor depends on: (1) the electromechanical coupling coefficient of the piezoelectric system; and (2) the ratio of the rectifier output voltage during operation to its maximum open-circuit value. When the DC-DC converter is maximizing power flow to the battery, this voltage ratio is very nearly 1/2, and the loss factor depends only on the coupling coefficient. Experiments on a base-driven piezoelectric cantilever, having a system coupling coefficient of 26%, yielded an effective loss factor for the fundamental vibration mode of 2.2%, in excellent agreement with theory.

Lesieutre, G. A.; Ottman, G. K.; Hofmann, H. F.

2004-01-01

228

Vibration-to-electric energy conversion using a mechanically-varied capacitor

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 ...

Yen, Bernard Chih-Hsun, 1981-

2005-01-01

229

Modelling of a bridge-shaped nonlinear piezoelectric energy harvester

NASA Astrophysics Data System (ADS)

Piezoelectric MicroElectroMechanical Systems (MEMS) energy harvesting is an attractive technology for harvesting small magnitudes of energy from ambient vibrations. Increasing the operating frequency bandwidth of such devices is one of the major issues for real world applications. A MEMS-scale doubly clamped nonlinear beam resonator is designed and developed to demonstrate very wide bandwidth and high power density. In this paper a first complete theoretical discussion of nonlinear resonating piezoelectric energy harvesting is provided. The sectional behaviour of the beam is studied through the Classical Lamination Theory (CLT) specifically modified to introduce the piezoelectric coupling and nonlinear Green-Lagrange strain tensor. A lumped parameter model is built through Rayleigh-Ritz Method and the resulting nonlinear coupled equations are solved in the frequency domain through the Harmonic Balance Method (HBM). Finally, the influence of external load resistance on the dynamic behaviour is studied. The theoretical model shows that nonlinear resonant harvesters have much wider power bandwidth than that of linear resonators but their maximum power is still bounded by the mechanical damping as is the case for linear resonating harvesters.

Gafforelli, G.; Xu, R.; Corigliano, A.; Kim, S. G.

2013-12-01

230

Thermal Energy Harvesting from Wildlife

NASA Astrophysics Data System (ADS)

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.

Woias, P.; Schule, F.; Bäumke, E.; Mehne, P.; Kroener, M.

2014-11-01

231

Soft Capacitors for Wave Energy Harvesting

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.

Karsten Ahnert; Markus Abel; Matthias Kollosche; Per Jørgen Jørgensen; Guggi Kofod

2011-04-21

232

Ultrasound acoustic wave energy transfer and harvesting

NASA Astrophysics Data System (ADS)

This paper investigates low-power electricity generation from ultrasound acoustic wave energy transfer combined with piezoelectric energy harvesting for wireless applications ranging from medical implants to naval sensor systems. The focus is placed on an underwater system that consists of a pulsating source for spherical wave generation and a harvester connected to an external resistive load for quantifying the electrical power output. An analytical electro-acoustic model is developed to relate the source strength to the electrical power output of the harvester located at a specific distance from the source. The model couples the energy harvester dynamics (piezoelectric device and electrical load) with the source strength through the acoustic-structure interaction at the harvester-fluid interface. Case studies are given for a detailed understanding of the coupled system dynamics under various conditions. Specifically the relationship between the electrical power output and system parameters, such as the distance of the harvester from the source, dimensions of the harvester, level of source strength, and electrical load resistance are explored. Sensitivity of the electrical power output to the excitation frequency in the neighborhood of the harvester's underwater resonance frequency is also reported.

Shahab, Shima; Leadenham, Stephen; Guillot, François; Sabra, Karim; Erturk, Alper

2014-04-01

233

Investigation of electrostrictive polymers for energy harvesting

The recent development of electrostrictive polymers has generated new opportunities for high-strain actuators. At the current time, the investigation of using electrostrictive polymer for energy harvesting, or mechanical to electrical energy conversion, is beginning to show its potential for this application. In this paper we discuss the mechanical and electrical boundary conditions for maximizing the energy harvesting density and mechanical-to-electrical

Yiming Liu; Kai Liang Ren; Heath F. Hofmann; Qiming Zhang

2005-01-01

234

Impact of Mobile Transmitter Sources on Radio Frequency Wireless Energy Harvesting

1 Impact of Mobile Transmitter Sources on Radio Frequency Wireless Energy Harvesting Antonio work that investigates the impact of energy transfer, especially concerning the energy gain, and possibly ambient sources of energy, such as the sun, wind, naturally occurring vibrations, among others

Sanyal, Sugata

235

A novel miniature thermomagnetic energy harvester

NASA Astrophysics Data System (ADS)

Nowadays, thermal-energy-harvesting is an important research topic for powering wireless sensors. Among numerous thermal-energy-harvesting approaches, some researchers demonstrated novel thermomagnetic-energy harvesters to convert a thermal-energy from an ambient temperature-difference to an electrical-output to power the sensors. However, the harvesters are too bulky to be integrated with the sensors embedded in tiny mechanical-structures for some structuralhealth- monitoring applications. Therefore, miniaturized harvesters are needed. Hence, we demonstrate a miniature thermomagnetic-energy harvester. The harvester consists of CuBe-beams, PZT-piezoelectric-sheet, Gd-soft-magnet, NdFeB-hard-magnet, and mechanical-frame. The piezoelectric-sheet and soft-magnet is bounded at fixed-end and freeend of the beams, respectively. The mechanical-frame assembles the beams and hard-magnet. The length×width×thickness of the harvester is 2.5cm×1.7cm×1.5cm. According to this, our harvester is 20-times smaller than the other harvesters. In the initial-state of the energy-harvesting, the beams' free-end is near the cold-side. Thus, the soft-magnet is cooled lower than its curie temperature (Tc) and consequently changed from paramagnetic to ferromagnetic. Therefore, a magnetic-attractive force is produced between the soft-magnet and hard-magnet. Consequently, the beams/soft-magnet are down-pulled toward the hard-magnet fixed on the hot-side. The soft-magnet closing to the hot-side is heated higher than its Tc and subsequently changed to paramagnetic. Consequently, the magnetic-force is eliminated thus the beams are rebounded to the initial-state. Hence, when the harvester is under a temperature-difference, the beams' pulling-down/back process is cyclic. Due to the piezoelectric effect, the piezoelectric-sheet fixed on the beams continuously produces voltage-response. Under the temperature-difference of 29°C, the voltage-response of the harvester is 30.4 mV with an oscillating-frequency of 0.098 Hz.

Chen, Chin-Chung; Chung, Tien-Kan; Cheng, Chi-Cheng; Tseng, Chia-Yuan

2014-03-01

236

NASA Astrophysics Data System (ADS)

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.

Durou, Hugo; Rossi, Carole; Brunet, Magali; Vanhecke, Claude; Bailly, Nicolas; Ardila, Gustavo; Ourak, Lamine; Ramond, Adrien; Simon, Patrice; Taberna, Pierre-Louis

2008-12-01

237

A low profile vibro-impacting energy harvester with symmetrical stops

NASA Astrophysics Data System (ADS)

This paper reports on an investigation into the use of a vibro-impact approach to construct a relatively broadband kinetic energy harvester. Potentially, the vibro-impacting process may be exploited as an autotuning mechanism for energy harvesting in an environment where the source vibration spectrum varies in time, such as an aircraft in flight. The energy harvester examined in this paper is based on a vibro-impacting oscillator with double-sided, symmetrical, piezoelectric bimorph-stops. The energy harvester operates in the frequency range of 100-113 Hz and has a (non-optimized) maximum energy of 5.3 mW from an rms host vibration of 450 mG.

Moss, Scott; Barry, Alex; Powlesland, Ian; Galea, Steve; Carman, Gregory P.

2010-12-01

238

Development of a biomechanical energy harvester

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

Qingguo Li; Veronica Naing; J Maxwell Donelan

2009-01-01

239

Low power interface IC's for electrostatic energy harvesting applications

NASA Astrophysics Data System (ADS)

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

Kempitiya, Asantha

240

Helmholtz Resonator for Lead Zirconate Titanate Acoustic Energy Harvester

NASA Astrophysics Data System (ADS)

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.

Matsuda, Tomohiro; Tomii, Kazuki; Hagiwara, Saori; Miyake, Shuntaro; Hasegawa, Yuichi; Sato, Takamitsu; Kaneko, Yuta; Nishioka, Yasushiro

2013-12-01

241

Seebeck nanoantennas for solar energy harvesting

NASA Astrophysics Data System (ADS)

We propose a mid-infrared device based on thermocouple optical antennas for light sensing and energy harvesting applications. We numerically demonstrate that antennas are able to generate low-power dc signals by beneficing of the thermoelectric properties of the metals that constitute them. We theoretically evaluate the optical-to-electrical conversion efficiency for harvesting applications and finally discuss strategies to increase its performance. Thermocouple optical antennas therefore open the route toward the design of photovoltaic devices.

Briones, E.; Briones, J.; Cuadrado, A.; Martinez-Anton, J. C.; McMurtry, S.; Hehn, M.; Montaigne, F.; Alda, J.; Gonzalez, F. J.

2014-09-01

242

Electromagnetic generator: As respiratory effort energy harvester

Human power is one form of renewable energy that has shown to be promising to provide a solution for powering personal electronic devices when other energy sources are not readily available while reducing environmental waste associated with battery disposal and eliminating the need for battery displacement. This paper introduces a new paradigm of human energy harvesting with the ultimate goal

Ehsaneh Shahhaidar; Olga Boric-Lubecke; Reza Ghorbani; Michael Wolfe

2011-01-01

243

MEMS electromagnetic energy harvesters with multiple resonances

NASA Astrophysics Data System (ADS)

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.

Nelatury, Sudarshan R.; Gray, Robert

2014-06-01

244

Flat inductors for human motion energy harvesting

NASA Astrophysics Data System (ADS)

The human motion energy harvesting is under investigation. The aim of this investigation: to develop electromagnetic human motion energy harvester that will consist only from flat elements and is integrable into the apparel. Main parts of the developed human motion energy harvester are flat, spiral-shaped inductors. Voltage pulses in such flat inductors can be induced during the motion of a permanent magnet along it. Due to the flat structure, inductors can be completely integrated into the parts of the clothes and it is not necessary to keep empty place for the movement of the magnet, as in usual electromagnetic harvesters. The prototype of the clothing, jacket with integrated electromagnetic human motion energy harvester with flat inductors is tested. The theoretical model for the induction of the electromotive force due to the magnet's movement is created for the basic shapes (round, rhombic, square) of the inductive elements and the results (shape of voltage pulse and generated energy) of the calculations are in a good qualitative and quantitative coincidence with an experimental research.

Blums, Juris; Terlecka, Galina; Gornevs, Ilgvars; Vilumsone, Ausma

2013-05-01

245

NASA Astrophysics Data System (ADS)

Power harvesters that extract energy from vibrating systems via piezoelectric transduction show strong potential for powering smart wireless sensor devices in applications of health condition monitoring of rotating machinery and structures. This paper presents an analytical method for modelling an electromechanical piezoelectric bimorph beam with tip mass under two input base transverse and longitudinal excitations. The Euler-Bernoulli beam equations were used to model the piezoelectric bimorph beam. The polarity-electric field of the piezoelectric element is excited by the strain field caused by base input excitation, resulting in electrical charge. The governing electromechanical dynamic equations were derived analytically using the weak form of the Hamiltonian principle to obtain the constitutive equations. Three constitutive electromechanical dynamic equations based on independent coefficients of virtual displacement vectors were formulated and then further modelled using the normalised Ritz eigenfunction series. The electromechanical formulations include both the series and parallel connections of the piezoelectric bimorph. The multi-mode frequency response functions (FRFs) under varying electrical load resistance were formulated using Laplace transformation for the multi-input mechanical vibrations to provide the multi-output dynamic displacement, velocity, voltage, current and power. The experimental and theoretical validations reduced for the single mode system were shown to provide reasonable predictions. The model results from polar base excitation for off-axis input motions were validated with experimental results showing the change to the electrical power frequency response amplitude as a function of excitation angle, with relevance for practical implementation.

Lumentut, M. F.; Howard, I. M.

2013-03-01

246

Enhanced output power by eigenfrequency shift in acoustic energy harvester

NASA Astrophysics Data System (ADS)

In our previous studies, multiple piezoelectric cantilever plates were placed inside a quarter-wavelength straight tube resonator to harvest low frequency acoustic energy. To investigate the modification of eigenmodes in the tube resonator due to the presence of piezoelectric plates, the eigenfrequency shift properties by introducing single and multiple rectangular blockages in open-closed ducts are studied by using 1D segmented Helmholtz equations, Webster horn equation, and finite element simulations. The first-mode eigenfrequency of the duct is reduced when the blockage is placed near the open inlet. The decrease of eigenfrequency leads to the enhancement of absorbed acoustic power in the duct. Furthermore, the first half of the tube resonator possesses high pressure gradient resulting in larger driving forces for the vibration motion of piezoelectric plates. Therefore, in our harvesters, it is better to place the piezoelectric plates in the first half of the tube resonator to obtain high output voltage and power.

Li, Bin; You, Jeong Ho

2014-04-01

247

Energy harvesting from base excitation of ionic polymer metal composites in fluid environments

In this paper, we analytically and experimentally study the energy harvesting capability of submerged ionic polymer metal composites (IPMCs). We consider base excitation of an IPMC strip that is shunted with an electric impedance and immersed in a fluid environment. We develop a modeling framework to predict the energy scavenged from the IPMC vibration as a function of the excitation

Matteo Aureli; Chekema Prince; Maurizio Porfiri; Sean D. Peterson

2010-01-01

248

Band-pass design optimization of piezoelectric cantilever bimorph energy harvester

NASA Astrophysics Data System (ADS)

Piezoelectric energy harvesting has become a feasible method for powering micro portable electronics and wireless sensor networks by converting ambient vibration energy into electrical energy. As a thumb of rule, it is critical to tune the resonant frequency of the generator to the frequency of the environmental vibrations in order to induce the maximum structural deformation and then the maximum converted electrical energy through piezoelectric effect. However, it is well-known that the ambient vibrations are not usually fixed in only one single frequency and could span over a limited frequency band. In this paper, a band-pass design optimization of piezoelectric cantilever bimorph (PCB) energy harvester is presented based on the system transfer function of the PCB generator presented in a previous literature. For such an energy harvester, a group of PCB with dimensions appropriately selected can be integrated into a band-pass energy harvester working over a limited frequency band if the dimensions of piezoelectric bimorphs and proof masses are appropriately chosen. Further, the finite element analysis (FEA) of such a band-pass energy harvester is performed in ANSYS to validate the theoretical proposal. The result shows that the band-pass design optimization leads to a piezoelectric generator working over a certain frequency band while keeping outputting the relatively stable open-circuit voltage.

Zhang, Long; Williams, Keith A.

2011-03-01

249

NASA Astrophysics Data System (ADS)

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.

Zhang, X. F.; Hu, S. D.; Tzou, H. S.

2014-12-01

250

Thermoelectric Microconverter for Energy Harvesting Systems

This paper presents a solution for energy microgeneration through energy harvesting by taking advantage of temperature differences that are converted into electrical energy using the Seebeck effect. A thermoelectric microconverter for energy scavenging systems that can supply low-power electronics was fabricated using thin films of bismuth and antimony tellurides. Thin films of n-type bismuth (Bi2Te3) and p-type antimony (Sb2Te3) tellurides

João Paulo Carmo; Luis Miguel Goncalves; José Higino Correia

2010-01-01

251

Elastically bounded flapping wing for energy harvesting

NASA Astrophysics Data System (ADS)

In this Letter, we present and discuss an energy harvesting device, based on a wing elastically bounded to a fixed support. Large amplitude and periodic oscillations can be induced when this system is subject to wind, if a few parameters are carefully set. A linear stability analysis as well as two-dimensional numerical simulations confirms the existence of instability regions in the parameter space. In order to harvest energy by using this system, different methods are considered. Preliminary results obtained by an electromagnetic coupling are presented.

Boragno, C.; Festa, R.; Mazzino, A.

2012-06-01

252

Piezoelectric energy harvester under parquet floor

NASA Astrophysics Data System (ADS)

The design, fabrication and testing of piezoelectric energy harvesting modules for floors is described. These modules are used beneath a parquet floor to harvest the energy of people walking over it. The harvesting modules consist of monoaxial stretched PVDF-foils. Multilayer modules are built up as roller-type capacitors. The fabrication process of the harvesting modules is simple and very suitable for mass production. Due to the use of organic polymers, the modules are characterized by a great flexibility and the possibility to create them in almost any geometrical size. The energy yield was determined depending on the dynamic loading force, the thickness of piezoelectric active material, the size of the piezoelectric modules, their alignment in the walking direction and their position on the floor. An increase of the energy yield at higher loading forces and higher thicknesses of the modules was observed. It was possible to generate up to 2.1mWs of electric energy with dynamic loads of 70kg using a specific module design. Furthermore a test floor was assembled to determine the influence of the size, alignment and position of the modules on the energy yield.

Bischur, E.; Schwesinger, N.

2011-03-01

253

Finite element modeling of piezoelectric energy harvesters

NASA Astrophysics Data System (ADS)

This article reports a novel finite element model of piezoelectric energy harvesters accounting for the effect of nonlinear interface circuits. The idea is to replace the energy harvesting circuit in parallel with the parasitic piezoelectric capacitance by an equivalent load impedance. This approach offers many advantages. First, the model itself can be implemented conveniently in commercial finite element softwares. Second, it directly provides system-level designs on the whole without resorting to circuit solvers. Third, the extensions to complicated structures such as array configurations are straightforward. The proposed finite element model is validated by considering the case of an array system endowed with the standard, parallel-/series-SSHI (synchronized switch harvesting on inductor) interfaces. Good agreement is found between simulation results and analytic estimates.

Wu, P. H.; Shu, Y. C.

2014-03-01

254

Network-Level Cooperation in Energy Harvesting Wireless Nikolaos Pappas*

battery to store the harvested energy. We study the impact of the energy constraints on the stability, acoustic, wind, and even ambient radio power. However, the additional functionality of harvesting energy the limited energy resources. The impact of network- level cooperation in an energy harvesting network

Paris-Sud XI, UniversitÃ© de

255

Rotational piezoelectric wind energy harvesting using impact-induced resonance

NASA Astrophysics Data System (ADS)

To improve the output power of a rotational piezoelectric wind energy harvester, impact-induced resonance is proposed to enable effective excitation of the piezoelectric cantilevers' vibration modes and obtain optimum deformation, which enhances the mechanical/electrical energy transformation. The impact force is introduced by forming a piezoelectric bimorph cantilever polygon that is fixed at the circumference of the rotating fan's internal surface. Elastic balls are placed inside the polygon. When wind rotates the device, the balls strike the piezoelectric cantilevers, and thus electricity is generated by the piezoelectric effect. The impact point is carefully chosen to use the first bending mode as much as possible, and thus maximize the harvesting efficiency. The design enables each bimorph to be struck in a similar area and every bimorph is struck in that area at different moments. As a result, a relatively stable output frequency can be obtained. The output frequency can also be changed by choosing different bimorph dimensions, which will also make the device simpler and the costs lower. A prototype piezoelectric energy harvester consisting of twelve piezoelectric cantilevers was constructed. The piezoelectric cantilevers were made from phosphor bronze, the lead zirconium titanate (PZT)-based bimorph cantilever had dimensions of 47 mm × 20 mm × 0.5 mm, and the elastic balls were made from steel with a diameter of 10 mm. The optimal DC output power was 613 ?W across the 20 k? resistor at a rotation speed of 200 r/min with an inscribed circle diameter of 31 mm.

Yang, Ying; Shen, Qinlong; Jin, Jiamei; Wang, Yiping; Qian, Wangjie; Yuan, Dewang

2014-08-01

256

ENERGY HARVESTING UTILISING THE GYROSCOPIC EFFECT

ENERGY HARVESTING UTILISING THE GYROSCOPIC EFFECT N.C. Townsend nick@soton.ac.uk Fluid Structure of a marine vessel can induce gyroscopic precession. x y Z 0 Figure 1: A Schematic of a Single Unit Gyroscopic the gyroscopic effect) Experimental sea trials will be conducted in 2011. The motivation behind the project

SÃ³bester, AndrÃ¡s

257

FR4-based electromagnetic energy harvester for wireless sensor nodes

NASA Astrophysics Data System (ADS)

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.

Hatipoglu, G.; Ürey, H.

2010-01-01

258

State of the art in acoustic energy harvesting

NASA Astrophysics Data System (ADS)

For portable and embedded smart, wireless electronic systems, energy harvesting from the ambient energy sources has gained immense interest in recent years. Several ambient energies exist in the environment of wireless sensor nodes (WSNs) that include thermal, solar, vibration and acoustic energy. This paper presents the recent development in the field of acoustic energy harvesters (AEHs). AEHs convert the acoustic energy into useful electrical energy for the operation of autonomous wireless sensors. Mainly, two types of AEHs (electromagnetic and piezoelectric based) have been developed and reported in literature. The power produced by the reported piezoelectric AEHs ranges from 0.68?pW to 30?mW however, the power generation of the developed electromagnetic AEHs is in the range of 1.5–1.96?mW. The overall size of most of the developed piezoelectric and electromagnetic AEHs are quite comparable and in millimeter scale. The resonant frequencies of electromagnetic AEHs are on the lower side (143–470?Hz), than that of piezoelectric AEHs (146?Hz–16.7?kHz).

Ullah Khan, Farid; Izhar

2015-02-01

259

The delocalized, anticorrelated component of pigment vibrations can drive nonadiabatic electronic energy transfer in photosynthetic light-harvesting antennas. In femtosecond experiments, this energy transfer mechanism leads to excitation of delocalized, anticorrelated vibrational wavepackets on the ground electronic state that exhibit not only 2D spectroscopic signatures attributed to electronic coherence and oscillatory quantum energy transport but also a cross-peak asymmetry not previously explained by theory. A number of antennas have electronic energy gaps matching a pigment vibrational frequency with a small vibrational coordinate change on electronic excitation. Such photosynthetic energy transfer steps resemble molecular internal conversion through a nested intermolecular funnel. PMID:23267114

Tiwari, Vivek; Peters, William K.; Jonas, David M.

2013-01-01

260

The delocalized, anticorrelated component of pigment vibrations can drive nonadiabatic electronic energy transfer in photosynthetic light-harvesting antennas. In femtosecond experiments, this energy transfer mechanism leads to excitation of delocalized, anticorrelated vibrational wavepackets on the ground electronic state that exhibit not only 2D spectroscopic signatures attributed to electronic coherence and oscillatory quantum energy transport but also a cross-peak asymmetry not previously explained by theory. A number of antennas have electronic energy gaps matching a pigment vibrational frequency with a small vibrational coordinate change on electronic excitation. Such photosynthetic energy transfer steps resemble molecular internal conversion through a nested intermolecular funnel. PMID:23267114

Tiwari, Vivek; Peters, William K; Jonas, David M

2013-01-22

261

Energy harvesting/scavenging for powering (-)sensors Lead: P. Basset.

Energy harvesting/scavenging for powering (Âµ-)sensors Lead: P. Basset. Permanent members: F. Marty Scavenger for Autonomous Microsystems (SESAM): The objective is the elaboration of an energy harvester

Baudoin, GeneviÃ¨ve

262

Inductive Energy Harvesting for Rotating Sensor Platforms

NASA Astrophysics Data System (ADS)

An inductive energy harvesting concept for structures rotating in proximity to a stationary body is proposed. The performance of such devices is studied analytically and numerically, and an experimental proof of concept is presented, demonstrating energy output density of 1 mW/cm3 from a typical geometry and rotation scale. The proposed approach may be suitable for powering retrofitted wireless sensors on engine bodies and also on rotating parts where complex stator-rotor wiring solutions would otherwise be required.

Toh, T. T.; Wright, S. W.; Kiziroglou, M. E.; Mitcheson, P. D.; Yeatman, E. M.

2014-11-01

263

Energy harvesting for self-powered nanosystems

In this article, an introduction is presented about the energy harvesting technologies that have potential for powering nanosystems.\\u000a Our discussion mainly focuses on the approaches other than the well-known solar cell and thermoelectrics. We mainly introduce\\u000a the piezoelectric nanogenerators developed using aligned ZnO nanowire arrays. This is a potential technology for converting\\u000a mechanical movement energy (such as body movement, muscle

Zhong Lin Wang

2008-01-01

264

Electroaeroelastic modeling and analysis of a hybrid piezoelectric-inductive flow energy harvester

NASA Astrophysics Data System (ADS)

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.

Dias, J. A. C.; De Marqui, C.; Erturk, Alper

2013-04-01

265

Nonlinear analysis of piezoelectric nanocomposite energy harvesting plates

NASA Astrophysics Data System (ADS)

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.

Rafiee, M.; He, X. Q.; Liew, K. M.

2014-06-01

266

Pyroelectric Nanogenerators for Harvesting Thermoelectric Energy Ken C. Pradel,

Information ABSTRACT: Harvesting thermoelectric energy mainly relies on the Seebeck effect that utilizes contact, Seebeck effect Wasted heat is a rich source of energy that could be harvested. In 2010- technology. Harvesting thermoelectric energy mainly relies on the Seebeck effect that utilizes a temperature

Wang, Zhong L.

267

Throughput of wireless networks powered by energy harvesting

Designing mobile devices for harvesting ambient energy such as kinetic activities or electromagnetic radiation (EMR) will enable mobile networks to self sustain besides alleviate global warming. The throughput of a mobile ad hoc network powered by energy harvesting is analyzed in this paper using a stochastic-geometry approach. The transmitters powered by energy harvesting are modeled as a Poisson point process

Kaibin Huang

2011-01-01

268

Anisotropic Phase Transformation of Poly (Vinylidene Difluoride) for Energy Harvesting

of microstructures of the PVDF on its piezoelectricity for energy harvesting. Using combined experimental techniquesAnisotropic Phase Transformation of Poly (Vinylidene Difluoride) for Energy Harvesting Wednesday&M University Poly (vinylidene difluoride) (PVDF) has been widely studied for energy harvesting of MEMS devices

Fisher, Frank

269

NASA Astrophysics Data System (ADS)

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.

Golub, Maksym; Irrgang, Klaus-Dieter; Rusevich, Leonid; Pieper, Jörg

2015-01-01

270

Energy Cooperation in Energy Harvesting Two-Way Communications

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

Ulukus, Sennur

271

Improving Energy Efficiency for Energy Harvesting Embedded Systems*

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

Qiu, Qinru

272

Multi-physics model of a thermo-magnetic energy harvester

NASA Astrophysics Data System (ADS)

Harvesting small thermal gradients effectively to generate electricity still remains a challenge. Ujihara et al (2007 Appl. Phys. Lett. 91 093508) have recently proposed a thermo-magnetic energy harvester that incorporates a combination of hard and soft magnets on a vibrating beam structure and two opposing heat transfer surfaces. This design has many advantages and could present an optimum solution to harvest energy in low temperature gradient conditions. In this paper, we describe a multi-physics numerical model for this harvester configuration that incorporates all the relevant parameters, including heat transfer, magnetic force, beam vibration, contact surface and piezoelectricity. The model was used to simulate the complete transient behavior of the system. Results are presented for the evolution of the magnetic force, changes in the internal temperature of the soft magnet (gadolinium (Gd)), thermal contact conductance, contact pressure and heat transfer over a complete cycle. Variation of the vibration frequency with contact stiffness and gap distance was also modeled. Limit cycle behavior and its bifurcations are illustrated as a function of device parameters. The model was extended to include a piezoelectric energy harvesting mechanism and, using a piezoelectric bimorph as spring material, a maximum power of 318 ?W was predicted across a 100 k? external load.

Joshi, Keyur B.; Priya, Shashank

2013-05-01

273

Flexible piezoelectric energy harvesting from jaw movements

NASA Astrophysics Data System (ADS)

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.

Delnavaz, Aidin; Voix, Jérémie

2014-10-01

274

Human Motion Energy Harvesting for AAL Applications

NASA Astrophysics Data System (ADS)

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.

Ylli, K.; Hoffmann, D.; Becker, P.; Willmann, A.; Folkmer, B.; Manoli, Y.

2014-11-01

275

Development of a biomechanical energy harvester

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

Li, Qingguo; Naing, Veronica; Donelan, J Maxwell

2009-01-01

276

A novel parametrically excited non-linear energy harvester

NASA Astrophysics Data System (ADS)

In this study, a method utilizing parametrical resonance for harvesting energy from low-frequency vibrations was investigated. A pendulum-type architecture with electromagnetic induction as the energy conversion mechanism was proposed. A prototype device with a natural frequency of approximately 2 Hz was fabricated and evaluated experimentally. The performance of the device was studied theoretically and numerically. The results were validated by experiments. It was found that the numerical results were consistent with the experimental measurements, while the theoretical analysis slightly overestimated the power output. In the cases considered, the proposed device demonstrated qualitatively different behaviors as compared to a conventional linear device. Such difference, e.g. broadened bandwidth and increased power output at higher damping levels, may be advantageous in certain applications.

Ma, Tian-Wei; Zhang, Hui; Xu, Ning-Shou

2012-04-01

277

Vibrational energy transfer in fluids

NASA Astrophysics Data System (ADS)

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.

Miller, David W.; Adelman, Steven A.

278

A wideband acoustic energy harvester using a three degree-of-freedom architecture

NASA Astrophysics Data System (ADS)

In this study, an acoustic energy harvester consisting of a perforated brass plate sandwiched between two cavities is designed and fabricated for scavenging energy from wide-spectrum acoustic sources. The multi-mode resonances of the device are adjusted closely spaced over a wide range of frequencies by properly tuned acoustic coupling of the vibrating plate and the two cavities. The experimental results show that the proximity of the multiple peaks enables the harvester operating in the frequency range of 1100-1400 Hz, which provides useful leads for the realization of acoustic energy generators of practical interest.

Peng, Xiao; Wen, Yumei; Li, Ping; Yang, Aichao; Bai, Xiaoling

2013-10-01

279

Environmental effects of harvesting forests for energy

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.

Van Hook, R.I.; Johnson, D.W.; West, D.C.; Mann, L.K.

1980-01-01

280

Models for 31-mode PVDF energy harvester for wearable applications.

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

Zhao, Jingjing; You, Zheng

2014-01-01

281

Flexible Electret Energy Harvester with Copper Mesh Electrodes

NASA Astrophysics Data System (ADS)

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.

Chiu, Yi; Lee, Ming Hsuan; Hsu, Wei-Hung

2014-11-01

282

Investigation of an energy harvesting small unmanned air vehicle

NASA Astrophysics Data System (ADS)

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.

Magoteaux, Kyle C.; Sanders, Brian; Sodano, Henry A.

2008-03-01

283

Design and analysis of a connected broadband multi-piezoelectric-bimorph- beam energy harvester.

The rapid growth of remote, wireless, and microelectromechanical system (MEMS) devices over the past decades has motivated the development of a self-powered system that can replace traditional electrochemical batteries. Piezoelectric energy harvesters are ideal for capturing energy from mechanical vibrations in the ambient environment. Numerous studies have been made of this application of piezoelectric energy conversion; however, the narrow frequency operation band has limited its application to generate useful power. In this paper, a broadband energy harvester with an array/matrix of piezoelectric bimorphs connected by springs has been designed and analyzed based on the 1-D piezoelectric beam equations. The predicted result shows that the operational frequency band can be enlarged significantly by carefully adjusting the small end masses, length of the beam and spring stiffness. An optimal selection of the load impedance to realize the maximum power output is discussed. The results provide an important foundation for future broadband energy harvester design. PMID:24859665

Zhang, Haifeng; Afzalul, Karim

2014-06-01

284

NASA Astrophysics Data System (ADS)

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.

Amini, Y.; Emdad, H.; Farid, M.

2014-09-01

285

Nonlinear output properties of cantilever driving low frequency piezoelectric energy harvester

NASA Astrophysics Data System (ADS)

Cantilever driving low frequency piezoelectric energy harvester (CANDLE) has been found as a promising structure for vibration energy harvesting. This paper presents the nonlinear output properties of the CANDLE to optimize the performance of the device. Simulation results of the finite element method illustrate that nonlinear contacts between the cymbal transducers and the cantilever beam are main reasons of the nonlinear output. However, high excitation acceleration of the nonlinear leap point limits the application of the device. Based on the simulation results and theory analysis, the excitation acceleration is reduced to 30 m/s2 by increasing the proof mass.

Xu, Chundong; Ren, Bo; Liang, Zhu; Chen, Jianwei; Zhang, Haiwu; Yue, Qingwen; Xu, Qing; Zhao, Xiangyong; Luo, Haosu

2012-11-01

286

A hybrid energy harvesting system for small battery powered applications

This paper presents a process of designing a hybrid energy harvesting system for small powered battery applications. The system is constructed with two separate systems that are the mechanical harvesting system and piezoelectric harvesting system. They are coupled together with an efficient power management circuit with the intention to generate electricity through walking while acting as a battery charger. The

Chang Ko Wei; Gobbi Ramasamy

2011-01-01

287

Jumping-droplet electrostatic energy harvesting

NASA Astrophysics Data System (ADS)

Micro- and nanoscale wetting phenomena have been an active area of research due to its potential for improving engineered system performance involving phase change. With the recent advancements in micro/nanofabrication techniques, structured surfaces can now be designed to allow condensing coalesced droplets to spontaneously jump off the surface due to the conversion of excess surface energy into kinetic energy. In addition to being removed at micrometric length scales (˜10 ?m), jumping water droplets also attain a positive electrostatic charge (˜10-100 fC) from the hydrophobic coating/condensate interaction. In this work, we take advantage of this droplet charging to demonstrate jumping-droplet electrostatic energy harvesting. The charged droplets jump between superhydrophobic copper oxide and hydrophilic copper surfaces to create an electrostatic potential and generate power during formation of atmospheric dew. We demonstrated power densities of ˜15 pW/cm2, which, in the near term, can be improved to ˜1 ?W/cm2. This work demonstrates a surface engineered platform that promises to be low cost and scalable for atmospheric energy harvesting and electric power generation.

Miljkovic, Nenad; Preston, Daniel J.; Enright, Ryan; Wang, Evelyn N.

2014-07-01

288

Tire tread deformation sensor and energy harvester development for smart-tire applications

NASA Astrophysics Data System (ADS)

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.

Moon, Kee S.; Liang, Hong; Yi, Jingang; Mika, Bartek

2007-04-01

289

Energy harvesting using a thermoelectric material

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.

Nersessian, Nersesse (Van Nuys, CA); Carman, Gregory P. (Los Angeles, CA); Radousky, Harry B. (San Leandro, CA)

2008-07-08

290

Thermoelectric energy harvesting with quantum dots

NASA Astrophysics Data System (ADS)

We review recent theoretical work on thermoelectric energy harvesting in multi-terminal quantum-dot setups. We first discuss several examples of nanoscale heat engines based on Coulomb-coupled conductors. In particular, we focus on quantum dots in the Coulomb-blockade regime, chaotic cavities and resonant tunneling through quantum dots and wells. We then turn toward quantum-dot heat engines that are driven by bosonic degrees of freedom such as phonons, magnons and microwave photons. These systems provide interesting connections to spin caloritronics and circuit quantum electrodynamics.

Sothmann, Björn; Sánchez, Rafael; Jordan, Andrew N.

2015-01-01

291

Thermoelectric energy harvesting with quantum dots.

We review recent theoretical work on thermoelectric energy harvesting in multi-terminal quantum-dot setups. We first discuss several examples of nanoscale heat engines based on Coulomb-coupled conductors. In particular, we focus on quantum dots in the Coulomb-blockade regime, chaotic cavities and resonant tunneling through quantum dots and wells. We then turn toward quantum-dot heat engines that are driven by bosonic degrees of freedom such as phonons, magnons and microwave photons. These systems provide interesting connections to spin caloritronics and circuit quantum electrodynamics. PMID:25549281

Sothmann, Björn; Sánchez, Rafael; Jordan, Andrew N

2015-01-21

292

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

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

293

Potential Ambient Energy-Harvesting Sources and Techniques

ERIC Educational Resources Information Center

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…

Yildiz, Faruk

2009-01-01

294

Multi-source energy harvester for wildlife tracking

NASA Astrophysics Data System (ADS)

Sufficient power supply to run GPS machinery and transmit data on a long-term basis remains to be the key challenge for wildlife tracking technology. Traditional way of replacing battery periodically is not only time and money consuming but also dangerous to live-trapping wild animals. In this paper, an innovative wildlife tracking device with multi-source energy harvester with advantage of high efficiency and reliability is investigated and developed. This multi-source energy harvester entails a solar energy harvester and an innovative rotational electromagnetic energy harvester is mounted on the "wildlife tracking collar" which will remarkably extend the duration of wild life tracking. A feedforward and feedback control of DC-DC converter circuit is adopted to passively realize the Maximum Power Point Tracking (MPPT) logic for the solar energy harvester. The rotational electromagnetic energy harvester can mechanically rectify the irregular bidirectional motion into unidirectional motion has been modeled and demonstrated.

Wu, You; Zuo, Lei; Zhou, Wanlu; Liang, Changwei; McCabe, Michael

2014-03-01

295

Piezoelectric energy harvesting: State-of-the-art and challenges

NASA Astrophysics Data System (ADS)

Piezoelectric energy harvesting has attracted wide attention from researchers especially in the last decade due to its advantages such as high power density, architectural simplicity, and scalability. As a result, the number of studies on piezoelectric energy harvesting published in the last 5 years is more than twice the sum of publications on its electromagnetic and electrostatic counterparts. This paper presents a comprehensive review on the history and current state-of-the art of piezoelectric energy harvesting. A brief theory section presents the basic principles of piezoelectric energy conversion and introduces the most commonly used mechanical architectures. The theory section is followed by a literature survey on piezoelectric energy harvesters, which are classified into three groups: (i) macro- and mesoscale, (ii) MEMS scale, and (iii) nanoscale. The size of a piezoelectric energy harvester affects a variety of parameters such as its weight, fabrication method, achievable power output level, and potential application areas. Consequently, size-based classification provides a reliable and effective basis to study various piezoelectric energy harvesters. The literature survey on each scale group is concluded with a summary, potential application areas, and future directions. In a separate section, the most prominent challenges in piezoelectric energy harvesting and the studies focusing on these challenges are discussed. The conclusion part summarizes the current standing of piezoelectric energy harvesters as possible candidates for various applications and discusses the issues that need to be addressed for realization of practical piezoelectric energy harvesting devices.

Toprak, Alperen; Tigli, Onur

2014-09-01

296

Size optimization of conical piezoelectric energy harvesters

NASA Astrophysics Data System (ADS)

The optimal design of piezoelectric patches on a piezoelectric conical energy harvester is presented in this study. Based on the equivalent voltage source model, the power of the resistance load is derived firstly. The origin location of the piezoelectric patch is set at the peak points of the modal voltage. The piezoelectric patch is in the region formed by the zero lines where the modal voltage is zero. The location of the peak points and the zero lines are determined by the spatial distribution of the modal voltage and the open-circuit voltage. Three parameters are chosen to locate the piezoelectric patch, i.e. the circumferential width, the length from the origin to the minor end and the length from the origin to the major end. Solving the extremum of the power equation with respect to the three parameters yields the optimal size of the piezoelectric patch. Case studies are given to evaluate the power of the optimal piezoelectric energy harvester. The results indicate that with the origin located at the optimal location, the power of resistance load firstly increases with the width and the lengths until the maximum and then decreases. The optimal width of the piezoelectric patch is 75% of the half-wave length for all of the evaluated modes.

Li, H.; Hu, S. D.; Tzou, H. S.

2015-01-01

297

Comparison of the piezoelectric energy harvesters with Si- MEMS and metal-MEMS

NASA Astrophysics Data System (ADS)

This paper presents the development of piezoelectric energy harvesters based on silicon and stainless steel substrates, which have the ability to harvest mechanical energy from surrounding vibrations and transform vibration energy into useful electrical power. Our experimental results show that the silicon-based device had a maximum output power of 0.9 ?W with 1.0 VP-P output voltage excited at 107.9 Hz under a 0.25 g vibrating source. The metal- based device had a maximum output power of 2.7 ?W with 1.5 VP-P output voltage at a vibration frequency of 108.6 Hz and 0.25 g acceleration. The areal power density was 0.02 ?W mm?2 and 0.05 ?W mm-2 for the devices based on silicon and on stainless steel, respectively. The silicon- based devices broke when the device excited exceed 0.25g acceleration, while the metal-based devices can sustained for vibration level higher than 2g acceleration. The stainless steel based device is therefore proved to be much more reliable than silicon based device.

Wu, W. J.; Chen, C. T.; Lin, S. C.; Kuo, C. L.; Wang, Y. J.; Yeh, S. P.

2014-11-01

298

Magnetocaloric piezoelectric composites for energy harvesting

NASA Astrophysics Data System (ADS)

Magnetocaloric alloy, Gd5Si2Ge2, was developed into a composite with the poly(vinylidene fluoride) (PVDF) piezoelectric polymer. This multifunctional material possesses unique properties that are suitable for energy conversion and harvesting. Experimental approaches include using an arc melting technique to synthesize the Gd5Si2Ge2 (GSG) alloy and the spinning casting method to fabricate the composite. The materials were characterized using various techniques at different length scales. These include atomic force microscopy (AFM), optical microscopy, scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS). The results indicated that the phase transformation of the magnetocaloric material close to its Curie temperature induced a significant increase in power generation in the piezoelectric polymer. The power output of a laminated structure was 1.1 mW, more than 200 thousand times higher than the piezoelectric materials alone (5.1 nW).

Cleveland, Michael; Liang, Hong

2012-04-01

299

Networking Low-Power Energy Harvesting Devices: Measurements and Algorithms

--Recent advances in energy harvesting materials and ultra-low-power communications will soon enable the realization types (rechargeable battery and a capacitor) require different algorithms. We develop algorithms energy inputs are stochastic. Index Terms--Energy harvesting, ultra-low-power networking, indoor radiant

Shepard, Kenneth

300

Energy Harvesting for Self-Powered Nanosystems Zhong Lin Wang

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

Wang, Zhong L.

301

Broadcasting with a battery limited energy harvesting rechargeable transmitter

We consider the minimization of the transmission completion time with a battery limited energy harvesting trans- mitter in a two-user AWGN broadcast channel. The transmitter has fixed number of packets for each receiver and energy is modeled to arrive (be harvested) at the transmitter at random instants. The battery at the transmitter has a finite storage capacity, hence energy may

Omur Ozel; Jing Yang; Sennur Ulukus

2011-01-01

302

The fundamental role of quantized vibrations in coherent light harvesting by cryptophyte algae

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.

Avinash Kolli; Edward J. O'Reilly; Gregory D. Scholes; Alexandra Olaya-Castro

2012-10-10

303

The fundamental role of quantized vibrations in coherent light harvesting by cryptophyte algae

NASA Astrophysics Data System (ADS)

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.

Kolli, Avinash; O'Reilly, Edward J.; Scholes, Gregory D.; Olaya-Castro, Alexandra

2012-11-01

304

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.

Berger, Alaina L.; Palik, Brian; D'Amato, Anthony W.; Fraver, Shawn; Bradford, John B.; Nislow, Keith; King, David; Brooks, Robert T.

2013-01-01

305

A comparison between nonlinear cantilever and buckled beam for energy harvesting

NASA Astrophysics Data System (ADS)

Nonlinear dynamics has become one of the key aspect to improve the efficiency of kinetic energy harvesters working in the real environment. Different methods based on the exploitation of the dynamical features of stochastic nonlinear oscillators using bi-stable piezoelectric cantilevers or buckled beams have been proposed in the past years. Such methods are shown to outperform standard linear oscillators and to overcome some of the most severe limitations of present approaches once applied to ambient vibrations. This work presents simulation results comparing the two methods. The same piezoelectric element subjected to a fixed vibrating body in a cantilever or bridge configuration has been simulated. The kinetic excitation considered is a zero mean exponentially correlated gaussian noise with different amplitudes. The piezoelectric oscillator output response has been obtained as a function of a nonlinear parameter. This work is intended to help designing the most performing energy harvester for real world applications starting from the same piezoelectric element.

Vocca, H.; Cottone, F.; Neri, I.; Gammaitoni, L.

2013-09-01

306

Development of a pre-packaged MEMS electret energy harvester before charging

NASA Astrophysics Data System (ADS)

A novel MEMS electret vibration energy harvester sealed in a package before charging is developed, which should improve the package reliability and long-term stability of the charges. With an early prototype in package, vertical electret on the comb drives has been successfully charged with soft X-ray photoionization, and up to 3.58 ?W has been obtained at 570 Hz and 2.2 g oscillation, which corresponds to the effectiveness as high as 42%.

Kim, Seonwoo; Fu, Qianyan; Hagiwara, Kei; Suzuki, Yuji

2014-11-01

307

An optimized method of harvesting vibrational energy with a piezoelectric element using a step-down DC-DC converter is presented. In this configuration, the converter regulates the power flow from the piezoelectric element to the desired electronic load. Analysis of the converter in discontinuous current conduction mode results in an expression for the duty cycle-power relationship. Using parameters of the mechanical system,

Geffrey K. Ottman; Heath F. Hofmann; George A. Lesieutre

2003-01-01

308

MEMS based pyroelectric thermal energy harvester

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.

Hunter, Scott R; Datskos, Panagiotis G

2013-08-27

309

Ultra-wide bandwidth piezoelectric energy harvesting

NASA Astrophysics Data System (ADS)

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 nonlinear stiffness, which provides a passive feedback and results in amplitude-stiffened Duffing mode resonance. This design has been fabricated into a compact MEMS device, which is about the size of a US quarter coin. Based on the open circuit voltage measurement, it is expected to have more than one order of magnitude improvement in both bandwidth (more than 20% of the peak frequency) and power density (up to 2 W/cm3) in comparison to the devices previously reported.

Hajati, Arman; Kim, Sang-Gook

2011-08-01

310

Energy Harvesting Using PVDF Piezoelectric Nanofabric

NASA Astrophysics Data System (ADS)

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) .

Shafii, Chakameh Shafii

311

Ekho: A Tool for Recording and Emulating Energy Harvesting Conditions

Ekho: A Tool for Recording and Emulating Energy Harvesting Conditions Ryan Archer Honors Thesis that Ekho is able to replay I-V surfaces while readjusting to the harvesting conditions as frequently as once in 4.3Âµs. Ekho is able to emulate changing energy conditions, adapting both to changes in supply

312

Energy harvesting for human wearable and implantable bio-sensors.

There are clear trade-offs between functionality, battery lifetime and battery volume for wearable and implantable wireless-biosensors which energy harvesting devices may be able to overcome. Reliable energy harvesting has now become a reality for machine condition monitoring and is finding applications in chemical process plants, refineries and water treatment works. However, practical miniature devices that can harvest sufficient energy from the human body to power a wireless bio-sensor are still in their infancy. This paper reviews the options for human energy harvesting in order to determine power availability for harvester-powered body sensor networks. The main competing technologies for energy harvesting from the human body are inertial kinetic energy harvesting devices and thermoelectric devices. These devices are advantageous to some other types as they can be hermetically sealed. In this paper the fundamental limit to the power output of these devices is compared as a function of generator volume when attached to a human whilst walking and running. It is shown that the kinetic energy devices have the highest fundamental power limits in both cases. However, when a comparison is made between the devices using device effectivenesses figures from previously demonstrated prototypes presented in the literature, the thermal device is competitive with the kinetic energy harvesting device when the subject is running and achieves the highest power density when the subject is walking. PMID:21097254

Mitcheson, Paul D

2010-01-01

313

Micro Seismic Electret Generator for Energy Harvesting T. Tsutsumino1

- 279 - Micro Seismic Electret Generator for Energy Harvesting T. Tsutsumino1 *, Y. Suzuki1 , N-ku, Yokohama, Kanagawa, 221-8757 Abstract Evaluation of a micro electret generator for energy harvesting material. In power generation experiments using a prototype seismic generator, maximum power output of 0

Kasagi, Nobuhide

314

Design considerations for solar energy harvesting wireless embedded systems

Sustainable operation of battery powered wireless embed- ded systems (such as sensor nodes) is a key challenge, and considerable research effort has been devoted to energy optimization of such systems. Environmental energy harvesting, in particular solar based, has emerged as a viable technique to supplement battery supplies. However, designing an efficient solar harvesting system to realize the potential benefits of

Vijay Raghunathan; Aman Kansal; Jason Hsu; Jonathan Friedman; Mani B. Srivastava

2005-01-01

315

RF energy harvesting techniques for wirelessly powered devices

A power source combined with energy harvesting can provide wireless devices for low maintenance cost or extended battery life. We reviewed RF energy harvesting circuits for delivering power to wireless system operating at very low power levels with high efficiency. We need to apply low power control techniques to perform smart management for the wirelessly powered devices. Index Terms —

Shiho Kim

2011-01-01

316

Comparison of energy harvesting power management techniques and application

There has been a significant increase in the research on energy harvesting device for low power applications in recreant years. This is due to smaller electronics power applications such as wireless and mobile electronics and the demand for better lifespan of batteries. One of the challenges of the harvesting energy from ambient is to convert, transfer and store the usable

M. S. M. Resali; H. Salleh

2010-01-01

317

Optimal scheduling on an energy harvesting Broadcast Channel

The minimization of transmission completion time for a given number of bits per user in an energy harvesting communication system, where energy harvesting instants are known in an offline manner is considered. An achievable rate region with structural properties satisfied by the 2-user AWGN Broadcast Channel capacity region is assumed. It is shown that even though all data are available

Mehmet Akif Antepli; Elif Uysal-Biyikoglu; Hakan Erkal

2011-01-01

318

The Internet of Tags: Energy-Harvesting Adaptive Algorithms

(IoTags). We believe that IoTags will be a key component of the Internet of Things (IoT). In the nearThe Internet of Tags: Energy-Harvesting Adaptive Algorithms Robert Margolies Ph.D. Candidate a top-down approach and develop energy harvesting adaptive algorithms to support the Internet of Tags

Hone, James

319

Novel two-stage piezoelectric-based ocean wave energy harvesters for moored or unmoored buoys

NASA Astrophysics Data System (ADS)

Harvesting mechanical energy from ocean wave oscillations for conversion to electrical energy has long been pursued as an alternative or self-contained power source. The attraction to harvesting energy from ocean waves stems from the sheer power of the wave motion, which can easily exceed 50 kW per meter of wave front. The principal barrier to harvesting this power is the very low and varying frequency of ocean waves, which generally vary from 0.1Hz to 0.5Hz. In this paper the application of a novel class of two-stage electrical energy generators to buoyant structures is presented. The generators use the buoy's interaction with the ocean waves as a low-speed input to a primary system, which, in turn, successively excites an array of vibratory elements (secondary system) into resonance - like a musician strumming a guitar. The key advantage of the present system is that by having two decoupled systems, the low frequency and highly varying buoy motion is converted into constant and much higher frequency mechanical vibrations. Electrical energy may then be harvested from the vibrating elements of the secondary system with high efficiency using piezoelectric elements. The operating principles of the novel two-stage technique are presented, including analytical formulations describing the transfer of energy between the two systems. Also, prototypical design examples are offered, as well as an in-depth computer simulation of a prototypical heaving-based wave energy harvester which generates electrical energy from the up-and-down motion of a buoy riding on the ocean's surface.

Murray, R.; Rastegar, J.

2009-03-01

320

Energy harvesting in the nonlinear two-masses piezoelastic system driven by harmonic excitations

NASA Astrophysics Data System (ADS)

We examine the energy harvesting system consisted of two different masses (magnets) attached to piezoelastic oscillators, coupled by the electric circuit, and driven by harmonic excitations. The nonlinearity of the system is achieved by variable distance between vibrating magnetic masses and the magnets attached directly to the harvester. We also introduce the mistuning parameter which describes the disproportion of vibrating masses (their ratio). In our work we examine the dependence of output power (in terms of mean squared voltage) generated on electric load on excitation frequencies for different values of mistuning parameter and additionally for different values of system nonlinearity parameter. We compare obtained results with the dia- grams presenting relative displacements of these oscillators (in terms of standard deviation) vs. excitation frequencies. In the second part of this paper we present the phase boundary lines (phase portraits) for selected values of applied frequency to show the complicated behavior of the oscillators in the nonlinear regime when the mistuning appears.

Kucab, K.; Górski, G.; Mizia, J.

2013-09-01

321

Impedance adaptation methods of the piezoelectric energy harvesting

NASA Astrophysics Data System (ADS)

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

Kim, Hyeoungwoo

322

COTTON HARVEST PREPARATION USING THERMAL ENERGY

Technology Transfer Automated Retrieval System (TEKTRAN)

Managing cotton for mechanical harvest requires the use of chemicals restricted in organic production. Thermal defoliation is an effective alternative resulting in rapid leaf desiccation. Field trials were needed to determine the best timing for thermal treatment and harvest. Crop termination usin...

323

Calculated rotation-vibration energies for HOC +

NASA Astrophysics Data System (ADS)

We use the ab initio potential surfaces discussed in the immediately preceding paper, with the nonrigid bender Hamiltonian, to calculate rotation-vibration energies for the ground electronic state of HOC +. The results obtained agree with the currently available experimental rotational energy level separations in four HOC + isotopes to within 0.03%. The predicted rotation-vibration energy separations should be of assistance in the experimental search for the corresponding transitions.

Bunker, P. R.; Jensen, Per; Kraemer, W. P.; Beardsworth, R.

1987-02-01

324

Calculated rotation-vibration energies for HOC+

We use the ab initio potential surfaces discussed in the immediately preceding paper, with the nonrigid bender Hamiltonian, to calculate rotation-vibration energies for the ground electronic state of HOC+. The results obtained agree with the currently available experimental rotational energy level separations in four HOC+ isotopes to within 0.03%. The predicted rotation-vibration energy separations should be of assistance in the

P. R. Bunker; Per Jensen; W. P. Kraemer; R. Beardsworth

1987-01-01

325

NASA Astrophysics Data System (ADS)

Conventional thermoacoustic-piezoelectric (TAP) harvesters convert thermal energy, such as solar or waste heat energy, directly into electrical energy without the need for any moving components. The input thermal energy generates a steep temperature gradient along a porous medium. At a critical threshold of the temperature gradient, self-sustained acoustic waves are developed inside an acoustic resonator. The associated pressure fluctuations impinge on a piezoelectric diaphragm, placed at the end of the resonator. In this study, the TAP harvester is coupled with an auxiliary elastic structure in the form of a simple spring-mass system to amplify the strain experienced by the piezoelectric element. The auxiliary structure is referred to as a dynamic magnifier and has been shown in different areas to significantly amplify the deflection of vibrating structures. A comprehensive model of the dynamically magnified thermoacoustic-piezoelectric (DMTAP) harvester has been developed that includes equations of motions of the system's mechanical components, the harvested voltage, the mechanical impedance of the coupled structure at the resonator end and the equations necessary to compute the self-excited frequencies of oscillations inside the acoustic resonator. Theoretical results confirmed that significant amplification of the harvested power is feasible if the magnifier's parameters are properly chosen. The performance characteristics of experimental prototypes of a thermoacoustic-piezoelectric resonator with and without the magnifier are examined. The obtained experimental findings are validated against the theoretical results. Dynamic magnifiers serve as a novel approach to enhance the effectiveness of thermoacoustic energy harvested from waste heat by increasing the efficiency of their harvesting components.

Nouh, M.; Aldraihem, O.; Baz, A.

2014-07-01

326

Analytical model for nonlinear piezoelectric energy harvesting devices

NASA Astrophysics Data System (ADS)

In this work we propose analytical expressions for the jump-up and jump-down point of a nonlinear piezoelectric energy harvester. In addition, analytical expressions for the maximum power output at optimal resistive load and the 3 dB-bandwidth are derived. So far, only numerical models have been used to describe the physics of a piezoelectric energy harvester. However, this approach is not suitable to quickly evaluate different geometrical designs or piezoelectric materials in the harvester design process. In addition, the analytical expressions could be used to predict the jump-frequencies of a harvester during operation. In combination with a tuning mechanism, this would allow the design of an efficient control algorithm to ensure that the harvester is always working on the oscillator's high energy attractor.

Neiss, S.; Goldschmidtboeing, F.; Kroener, M.; Woias, P.

2014-10-01

327

Control of Vibratory Energy Harvesters in the Presence of Nonlinearities and Power-Flow Constraints

NASA Astrophysics Data System (ADS)

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.

Cassidy, Ian L.

328

Energy harvesting with piezoelectric grass for autonomous self-sustaining sensor networks

NASA Astrophysics Data System (ADS)

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.

Hobeck, Jared Dale

329

This paper reports on efficient interfacing of typical vibration-driven electromagnetic transducers for micro energy harvesting. For this reason, an adaptive charge pump for dynamic maximum power point tracking is compared with a novel active full-wave rectifier design. For efficient ultra-low voltage rectification, the introduced active diode design uses a common-gate stage in conjunction with supply-independent biasing. While this active rectifier

Dominic Maurath; Philipp F. Becker; Dirk Spreemann; Yiannos Manoli

2012-01-01

330

High temperature energy harvester for wireless sensors

NASA Astrophysics Data System (ADS)

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.

Köhler, J. E.; Heijl, R.; Staaf, L. G. H.; Zenkic, S.; Svenman, E.; Lindblom, A.; Palmqvist, A. E. C.; Enoksson, P.

2014-09-01

331

Energy harvesting based on piezoelectric Ericsson cycles in a piezoceramic material

NASA Astrophysics Data System (ADS)

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.

Zhang, B.; Ducharne, B.; Guyomar, D.; Sebald, G.

2013-09-01

332

On Kinetics Modeling of Vibrational Energy Transfer

NASA Technical Reports Server (NTRS)

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.

Gilmore, John O.; Sharma, Surendra P.; Cavolowsky, John A. (Technical Monitor)

1996-01-01

333

Parametric studies on the harvested energy of piezoelectric switching techniques

NASA Astrophysics Data System (ADS)

Piezoelectric energy harvesting techniques have experienced increasing research effort during the last few years. Possible applications including wireless, fully autonomous electronic devices, such as sensors, have attracted great interest. The key aspect of harvesting techniques is the amount of converted and stored energy, because the energy source and the conversion rate is limited. In particular, switching techniques offer many parameters that can be optimized. It is therefore crucial to examine the influence of these parameters in a precise manner. This paper addresses an accurate analytical modeling approach, facilitating the calculation of standard-DC and parallel SSHI-DC energy harvesting circuits. In particular the influence of the frequency ratio between the excitation and the electrical resonance of the switching LR-branch, and the voltage gaps across the rectifier diodes are studied in detail. Additionally a comparison with the SSDI damping network is performed. The relationship between energy harvesting and damping is indicated in this paper.

Neubauer, M.; Krack, M.; Wallaschek, J.

2010-02-01

334

Innovative thermal energy harvesting for future autonomous applications

NASA Astrophysics Data System (ADS)

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.

Monfray, Stephane

2013-12-01

335

Scaling of electromagnetic transducers for shunt damping and energy harvesting

NASA Astrophysics Data System (ADS)

In order for an electromagnetic transducer to operate well as either a mechanical shunt damper or as a vibration energy harvester, it must have good electromechanical coupling. A simple two-port analysis is used to derive a non-dimensional measure of electromechanical coupling, which must be large compared with unity for efficient operation in both of these applications. The two-port parameters for an inertial electromagnetic transducer are derived, from which this non-dimensional coupling parameter can be evaluated. The largest value that this parameter takes is approximately equal to the square of the magnetic flux density times the length of wire in the field, divided by the mechanical damping times the electrical resistance. This parameter is found to be only of the order of one for voice coil devices that weigh approximately 1 kg, and so such devices are generally not efficient, within the definition used here, in either of these applications. The non-dimensional coupling parameter is found to scale in approximate proportion to the device's characteristic length, however, and so although miniaturised devices are less efficient, greater efficiency can be obtained with large devices, such as those used to control civil engineering structures.

Elliott, Stephen J.; Zilletti, Michele

2014-04-01

336

Evaluation of flexible transducers for motion energy harvesting

NASA Astrophysics Data System (ADS)

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.

Collins, Michael; Behrens, Sam; McGarry, Scott

2009-03-01

337

The effects of collision energy, vibrational mode, and vibrational angular momentum on energy effects of NO2 + vibrational excitation that extend over the entire collision energy range, implying dynamics trajectories for NO2 + +Kr reproduce both the collision energy and vibrational state effects

Anderson, Scott L.

338

Design of test bench apparatus for piezoelectric energy harvesters

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 ...

Yoon, You C. (You Chang)

2013-01-01

339

Microbial fuel cell energy harvesting using synchronous flyback converter

NASA Astrophysics Data System (ADS)

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.

Alaraj, Muhannad; Ren, Zhiyong Jason; Park, Jae-Do

2014-02-01

340

The vibrational energy pattern acetylene ''VI...: Inter and intrapolyad structures

The vibrational energy pattern acetylene ''VI...: InterÂ and intrapolyad structures B. I. Zhilinski March 2000; accepted August 2000# IntraÂ interpolyad structures are investigated vibrational energy of vibrational energy levels. Distinct regular oscillatory contributions evidenced number vibrational levels main

ZhilinskiÃ, Boris

341

Infrared Energy Harvesting for Optoplasmonics from Nanostructured Metamaterials

NASA Astrophysics Data System (ADS)

Metamaterials exhibit unique optical resonance characteristics which permit precise engineering of energy pathways within a device. The ability of plasmonic nanostructures to guide electromagnetism offers a platform to reduce global dependence on fossil fuels by harvesting waste heat, which comprises 60% of generated energy around the world. Plasmonic metamaterials were hypothesized to support an exchange of energy between resonance modes, enabling generation of higher energy photons from waste infrared energy. Infrared irradiation of a metamaterial at the Fano coupling lattice resonance was anticipated to re-emit as higher energy visible light at the plasmon resonance. Photonic signals from harvested thermal energy could be used to power wearable medical monitors or off-grid excursions, for example. This thesis developed the design, fabrication, and characterization methods to realize nanostructured metamaterials which permit resonance exchange for infrared energy harvesting applications.

Forcherio, Gregory Thomas

342

Flexible Piezoelectric Thin-Film Energy Harvesters and Nanosensors for Biomedical Applications.

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

Hwang, Geon-Tae; Byun, Myunghwan; Jeong, Chang Kyu; Lee, Keon Jae

2014-12-01

343

Fokker-Planck equation analysis of randomly excited nonlinear energy harvester

NASA Astrophysics Data System (ADS)

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.

Kumar, P.; Narayanan, S.; Adhikari, S.; Friswell, M. I.

2014-03-01

344

Converged vibrational energy levels and quantum mechanical vibrational partition function of ethane

Converged vibrational energy levels and quantum mechanical vibrational partition function of ethane-0431 Received 25 January 2006; accepted 15 March 2006; published online 9 May 2006 The vibrational partition that were calculated by vibrational configuration interaction, and the results are compared to the harmonic

Truhlar, Donald G

345

A shoe-embedded piezoelectric energy harvester for wearable sensors.

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

Zhao, Jingjing; You, Zheng

2014-01-01

346

Insole pedometer with piezoelectric energy harvester and 2V organic digital and analog circuits

Energy harvesting is an enabling technology for realizing an ambient power supply for wireless sensor nodes and mobile devices. By using flexible photovoltaic cells and piezoelectric films, we can readily harvest ambient energy if flexible energy harvesters can be realized. Conventional silicon circuits, however, are not best suited to realizing flexible large-area energy harvesters because they are not mechanically conformable

Koichi Ishida; Tsung-Ching Huang; Kentaro Honda; Yasuhiro Shinozuka; Hiroshi Fuketa; Tomoyuki Yokota; Ute Zschieschang; Hagen Klauk; Gregory Tortissier; Tsuyoshi Sekitani; Makoto Takamiya; Hiroshi Toshiyoshi; Takao Someya; Takayasu Sakurai

2012-01-01

347

This study presents a synthesis of a new energy harvest system that consists of a hula-hoop transformer, a micro-generator\\u000a and an interface energy harvest circuit. The hula-hoop transformer mainly comprises a main mass sprung in one translational\\u000a direction and a free-moving mass attached at one end of a rod, the other end of which is hinged onto the main mass.

Paul C.-P. Chao; C. I. Shao; C. X. Lu; C. K. Sung

2011-01-01

348

A technique for giant mechanical energy harvesting using ferroelectric/antiferroelectric materials

NASA Astrophysics Data System (ADS)

Ferroelectric materials are widely employed as piezoelectric materials for numerous energy harvesting systems. However, conventional systems employing direct piezoelectric effect for vibrational energy harvesting suffer from low energy density and high actuation frequency requirements. In this regards, the authors have presented a new technique for giant mechanical energy conversion using ferroelectric/antiferroelectric materials in a cyclic manner. The proposed method will allow for large electromechanical energy conversion in a wide frequency domain. The cycle was simulated for polycrystalline Pb0.99Nb0.02[(Zr0.57Sn0.43)0.94Ti0.06]0.98O3 (PNZST) antiferroelectric bulk ceramic. It was observed that for cycle parameters of (20 to 60 kV.cm-1 and 0 to 250 MPa), a harvesting energy density of 689 kJ.m-3.cycle-1 can be obtained for uniaxial compressive stress. While an energy density of 919 kJ.m-3.cycle-1 can be obtained for radial compressive stress with cycle parameters of (20 to 60 kV.cm-1 and 0 to 360 MPa). This is several orders of magnitude larger than the highest energy density reported in the literature.

Patel, Satyanarayan; Chauhan, Aditya; Vaish, Rahul

2014-02-01

349

COTTON HARVEST PREPARATION USING THERMAL ENERGY

Technology Transfer Automated Retrieval System (TEKTRAN)

Cotton is prepared for mechanical harvest using desiccant and defoliant chemicals. Conventional chemical defoliation is not effective immediately, it requires a period of good weather, and it is restricted in organic production. This study was conducted to determine what impact thermal defoliation...

350

Power Generation Characteristics of Single Electrode Output Circuit in Electret Energy Harvester

NASA Astrophysics Data System (ADS)

This paper reports the new output circuit using a single electrode in electret energy harvester, and proves that the single electrode is able to generate output power on grounded load. 3D numerical model of gap-closing type electret energy harvester is presented, and power generation characteristics are analysed and verified. Results show that the two electrodes are actually two independent current sources. Single electrode output circuit has two merits: when only one electrode is connected, it reduces wiring difficulty; when both electrodes are connected to grounded load respectively, it doubles output power compared with traditional output circuit. Using proposed circuit, maximal total power of 30mm×20mm prototype reaches 154.5?W@10Hz, 1.8mm sinusoidal vibration, and an LED has been successfully lighted up.

Bu, L.; Xu, H. Y.; Xu, B. J.; Song, L.

2014-11-01

351

Hybrid energy harvester based on nanopillar solar cells and PVDF nanogenerator

NASA Astrophysics Data System (ADS)

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.

Lee, Dae-Yeong; Kim, Hyunjin; Li, Hua-Min; Jang, A.-Rang; Lim, Yeong-Dae; Cha, Seung Nam; Park, Young Jun; Kang, Dae Joon; Jong Yoo, Won

2013-05-01

352

Single stage AC-DC converter for Galfenol-based micro-power energy harvesters

NASA Astrophysics Data System (ADS)

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.

Cavaroc, Peyton; Curtis, Chandra; Naik, Suketu; Cooper, James

2014-06-01

353

Harvesting Energy from the Counterbalancing (Weaving) Movement in Bicycle Riding

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, Yoonseok; Yeo, Jeongjin; Priya, Shashank

2012-01-01

354

Harvesting energy from the counterbalancing (weaving) movement in bicycle riding.

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, Yoonseok; Yeo, Jeongjin; Priya, Shashank

2012-01-01

355

Energy Aware Dynamic Voltage and Frequency Selection for Real-Time Systems with Energy Harvesting

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

Qiu, Qinru

356

Real-Time Scheduling for Energy Harvesting Sensors

and limited by the capacity of the energy storage (battery or ultra-capacitor). In general, these embedded based, etc. The energy harvested from the environment can be stored in either batteries or ultra-capacitors. Batteries have a higher energy density and lower leakage, while ultra-capacitors have a higher round trip

Paris-Sud XI, UniversitÃ© de

357

Evaluation of motions and actuation methods for biomechanical energy harvesting

This paper addresses energy harvesting from biomechanical motions. Such a technique is useful for powering small portable devices, such as wireless phones, music players, and digital assistants. For very low power devices, biomechanical energy may be enough to provide baseload power. In others, such as cell phones (which typically requires up to 3 W), biomechanical energy would recharge batteries for

Penglin Niu; Patrick Chapman; Raziel Riemer; Xudong Zhang

2004-01-01

358

Wi-Pie: Energy Harvesting in Mobile Electronic Devices

A recent study puts the number of mobile phones in use around the world at an astonishing 5 billion and these numbers are growing rapidly. This places the increase in energy consumption of mobile phones in the world at an alarming level. Wi-Pie or Wireless-Piezoelectric technique combines RF energy scavenging and piezoelectric energy harvesting technologies to provide an alternative method

B. Guru Karthik; S. Shivaraman; V. Aditya

2011-01-01

359

Large-scale self-tuning solid-state kinetic energy harvester

NASA Astrophysics Data System (ADS)

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.

Pletner, Baruch; Swan, Lukas; Wettels, Nicholas; Joseph, Alain

2012-04-01

360

A Piezoelectric PZT Ceramic Mulitlayer Stack for Energy Harvesting Under Dynamic Forces

NASA Technical Reports Server (NTRS)

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.

Xu, Tian-Bing; Siochi, Emilie J.; Kang, Jin Ho; Zuo, Lei; Zhou, Wanlu; Tang, Xiudong; Jiang, Xiaoning

2011-01-01

361

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

Hu, Youfan; Yang, Jin; Niu, Simiao; Wu, Wenzhuo; Wang, Zhong Lin

2014-07-22

362

Energy issues in WSN for Aeronautics Applications: Harvesting and Scavenging, Power Management: harvesting vs scavenging Â· An example of energy capture: thermoelectricity Â· Energy storage Â· Energy Â· Energy issue: harvesting vs scavenging Â· An example of energy capture: thermoelectricity Â· Energy storage

Ingrand, FranÃ§ois

363

Energy harvesting: an integrated view of materials, devices and applications

NASA Astrophysics Data System (ADS)

Energy harvesting refers to the set of processes by which useful energy is captured from waste, environmental, or mechanical sources and is converted into a usable form. The discipline of energy harvesting is a broad topic that includes established methods and materials such as photovoltaics and thermoelectrics, as well as more recent technologies that convert mechanical energy, magnetic energy and waste heat to electricity. This article will review various state-of-the-art materials and devices for direct energy conversion and in particular will include multistep energy conversion approaches. The article will highlight the nano-materials science underlying energy harvesting principles and devices, but also include more traditional bulk processes and devices as appropriate and synergistic. Emphasis is placed on device-design innovations that lead to higher efficiency energy harvesting or conversion technologies ranging from the cm/mm-scale down to MEMS/NEMS (micro- and nano-electromechanical systems) devices. Theoretical studies are reviewed, which address transport properties, crystal chemistry, thermodynamic analysis, energy transfer, system efficiency and device operation. New developments in experimental methods; device design and fabrication; nanostructured materials fabrication; materials properties; and device performance measurement techniques are discussed.

Radousky, H. B.; Liang, H.

2012-12-01

364

Energy harvesting: an integrated view of materials, devices and applications.

Energy harvesting refers to the set of processes by which useful energy is captured from waste, environmental, or mechanical sources and is converted into a usable form. The discipline of energy harvesting is a broad topic that includes established methods and materials such as photovoltaics and thermoelectrics, as well as more recent technologies that convert mechanical energy, magnetic energy and waste heat to electricity. This article will review various state-of-the-art materials and devices for direct energy conversion and in particular will include multistep energy conversion approaches. The article will highlight the nano-materials science underlying energy harvesting principles and devices, but also include more traditional bulk processes and devices as appropriate and synergistic. Emphasis is placed on device-design innovations that lead to higher efficiency energy harvesting or conversion technologies ranging from the cm/mm-scale down to MEMS/NEMS (micro- and nano-electromechanical systems) devices. Theoretical studies are reviewed, which address transport properties, crystal chemistry, thermodynamic analysis, energy transfer, system efficiency and device operation. New developments in experimental methods; device design and fabrication; nanostructured materials fabrication; materials properties; and device performance measurement techniques are discussed. PMID:23186865

Radousky, H B; Liang, H

2012-12-21

365

Long term performance of wearable transducer for motion energy harvesting

NASA Astrophysics Data System (ADS)

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.

McGarry, Scott A.; Behrens, Sam

2010-04-01

366

A Skin-attachable Flexible Piezoelectric Pulse Wave Energy Harvester

NASA Astrophysics Data System (ADS)

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.

Yoon, Sunghyun; Cho, Young-Ho

2014-11-01

367

Energy harvesting from human motion: exploiting swing and shock excitations

NASA Astrophysics Data System (ADS)

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.

Ylli, K.; Hoffmann, D.; Willmann, A.; Becker, P.; Folkmer, B.; Manoli, Y.

2015-02-01

368

Unidirectional vibrational energy flow in nitrobenzene.

Experiments were performed on nitrobenzene liquid at ambient temperature to probe vibrational energy flow from the nitro group to the phenyl group and vice versa. The IR pump, Raman probe method was used. Quantum chemical calculations were used to sort the normal modes of nitrobenzene into three categories: phenyl modes, nitro modes, and global modes. IR wavelengths in the 2500-3500 cm(-1) range were found that best produced excitations initially localized on nitro or phenyl. Pulses at 2880 cm(-1) excited a nitro stretch combination band. Pulses at 3080 cm(-1) excited a phenyl C-H stretch plus some nitro stretch. With nitro excitation there was no detectable energy transfer to phenyl. With phenyl excitation there was no direct transfer to nitro, but there was some transfer to global modes such as phenyl-nitro stretching, so some of the vibrational amplitude on phenyl moved onto nitro. Thus energy transfer from nitro to phenyl was absent, but there was weak energy transfer from phenyl to nitro. The experimental methods described here can be used to study vibrational energy flow from one part of a molecule to another, which could assist in the design of molecules for molecular electronics and phononics. The vibrational isolation of the nitro group when attached to a phenyl moiety suggests that strongly nonthermal reaction pathways may play an important role in impact initiation of energetic materials having peripheral nitro groups. PMID:23432106

Pein, Brandt C; Sun, Yuxiao; Dlott, Dana D

2013-07-25

369

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

Li, Hao; Zhang, Gaofei; Ma, Rui; You, Zheng

2014-01-01

370

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

Li, Hao; Zhang, Gaofei; Ma, Rui; You, Zheng

2014-01-01

371

Harvesting Residuals-Economic Energy Link

is felling and forwarding full trees to roadside. At roadside the options are to produce tree lengths, sectioned stems or short wood. A project completed by Miramichi Pulp and Paper Inc. in 1984 used all of these options but varied residue production... in each instance. The usual method is to limb and top trees at a roadside landing, transport the tree lengths to a sawmill or pulp mill and chip the harvesting residuals for fuel. In the second option trees are felled and bucked into 3m sections...

Owens, E. T.; Curtis, D. B.

372

Performance evaluation of resource allocation policies for energy harvesting devices

We focus on resource allocation for energy harvest- ing devices. We analytically and numerically evaluate the perfor- mance of algorithms that determine time fair energy allocation in systems withpredictableandstochasticenergy inputs. To gain insight into the performance of networks of devices, we obtain results for the simple cases of a single node and a link. Due to the need for low

Maria Gorlatova; Andrey Bernstein; Gil Zussman

2011-01-01

373

Wireless energy transmission to supplement energy harvesters in sensor network applications

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.

Farinholt, Kevin M [Los Alamos National Laboratory; Taylor, Stuart G [Los Alamos National Laboratory; Park, Gyuhae [Los Alamos National Laboratory; Farrar, Charles R [Los Alamos National Laboratory

2010-01-01

374

A batch process micromachined thermoelectric energy harvester: fabrication and characterization

NASA Astrophysics Data System (ADS)

Micromachined thermopiles are considered as a cost-effective solution for energy harvesters working at a small temperature difference and weak heat flows typical for, e.g., the human body. They can be used for powering autonomous wireless sensor nodes in a body area network. In this paper, a micromachined thermoelectric energy harvester with 6 µm high polycrystalline silicon germanium (poly-SiGe) thermocouples fabricated on a 6 inch wafer is presented. An open circuit voltage of 1.49 V and an output power of 0.4 µW can be generated with 3.5 K temperature difference in a model of a wearable micromachined energy harvester of the discussed design, which has a die size of 1.0 mm × 2.5 mm inside a watch-size generator.

Su, J.; Leonov, V.; Goedbloed, M.; van Andel, Y.; de Nooijer, M. C.; Elfrink, R.; Wang, Z.; Vullers, R. J. M.

2010-10-01

375

Thermoelectric energy harvester on the heated human machine

NASA Astrophysics Data System (ADS)

Thermal properties of humans were studied in the case where a relatively small energy harvester is placed on the body. In such a case, the human body serves as a natural heat supply for wearable thermopiles. The study shows that relevant local body properties such as skin temperature and heat flow essentially change because of the thermal properties of the energy harvester. It is shown in the experiment that the thermal resistance of a human depends on heat flow, i.e. on the thermal properties of a thermoelectric generator (TEG) placed in contact with the skin. High thermal resistance of the human body, in turn, essentially affects the TEG design. The analysis of a wearable TEG, in particular the thin one, is performed. It shows that wearable energy harvesters could reach competitive performance characteristics for successfully replacing batteries in low-power wearable electronics. This paper was originally invited as part of the Power MEMS 2010 special issue.

Leonov, Vladimir

2011-12-01

376

Vibrational energy transport in molecular wires

NASA Astrophysics Data System (ADS)

Motivated by recent experimental observation (see, e.g., I. V. Rubtsov, Acc. Chem. Res. 42, 1385 (2009)) of vibrational energy transport in (CH2O) N and (CF2) N molecular chains ( N = 4-12), in this paper we present and solve analytically a simple one dimensional model to describe theoretically these data. To mimic multiple conformations of the molecular chains, our model includes random off-diagonal couplings between neigh-boring sites. For the sake of simplicity, we assume Gaussian distribution with dispersion ? for these coupling matrix elements. Within the model we find that initially locally excited vibrational state can propagate along the chain. However, the propagation is neither ballistic nor diffusion like. The time T m for the first passage of the excitation along the chain, scales linearly with N in the agreement with the experimental data. Distribution of the excitation energies over the chain fragments (sites in the model) remains random, and the vibrational energy, transported to the chain end at t = T m is dramatically decreased when ? is larger than characteristic interlevel spacing in the chain vibrational spectrum. We do believe that the problem we have solved is not only of intellectual interest (or to rationalize mentioned above experimental data) but also of relevance to design optimal molecular wires providing fast energy transport in various chemical and biological reactions.

Benderskii, V. A.; Kotkin, A. S.; Rubtsov, I. V.; Kats, E. I.

2013-10-01

377

Electromagnetic Energy Harvester by Using NdFeB Sputtered on High Aspect Ratio Si Structure

NASA Astrophysics Data System (ADS)

This study addresses the design optimization of the electromagnetic energy harvester consisting of the sputtered NdFeB film on a high aspect ratio corrugated Si structure and Au electroplated serpentine coil. The high-aspect-ratio Si structure has advantages that the magnetic flux density change is caused by distance change between the coil and magnet film on the fine-patterned corrugated Si, and it is easier to fabricate with high yield than previous study. We also optimized design parameters such as width and depth of the trench, coil size by using FEM analysis and theoretical calculations. Assuming the mass size of 10×10 mm2, the trench depth of the 400 ?m, the vibration amplitude of 40 ?m p-p and the vibration frequency of 100 Hz, the maximum output power of 12 nW and the maximum electromotive force of 4 mV are obtained for 60 ?m and 80 ?m magnet widths, respectively.

Tanaka, Y.; Fujita, T.; Kotoge, T.; Yamaguchi, K.; Sonoda, K.; Kanda, K.; Maenaka, K.

2013-12-01

378

Bringing Robustness and Power Efficiency to Autonomous Energy Harvesting Microsystems

Autonomous devices that are self-powered by extracting their energy from their environment are a new opportunity for monitoring purposes. A multi-energy sources and multi-sensors microsystem targeting autonomous wireless sensor node applications is presented. Since the available energy is not constant over time and due to very low harvested power levels, an efficient energy and power management strategy is mandatory. In

J. F. Christmann; E. Beigne?; C. Condemine; N. Leblond; P. Vivet; G. Waltisperger; J. Willemin

2010-01-01

379

Harvesting renewable energy from Earth's mid-infrared emissions.

It is possible to harvest energy from Earth's thermal infrared emission into outer space. We calculate the thermodynamic limit for the amount of power available, and as a case study, we plot how this limit varies daily and seasonally in a location in Oklahoma. We discuss two possible ways to make such an emissive energy harvester (EEH): A thermal EEH (analogous to solar thermal power generation) and an optoelectronic EEH (analogous to photovoltaic power generation). For the latter, we propose using an infrared-frequency rectifying antenna, and we discuss its operating principles, efficiency limits, system design considerations, and possible technological implementations. PMID:24591604

Byrnes, Steven J; Blanchard, Romain; Capasso, Federico

2014-03-18

380

Vibration-to-electric energy conversion

A system is proposed to convert ambient mechanical vibration into electrical energy for use in powering autonomous low-power electronic systems. The energy is transduced through the use of a variable capacitor, which has been designed with MEMS (microelectromechanical systems) tech- nology. A low-power controller IC has been fabricated in a 0 6µm CMOS pro- cess and has been tested and

Scott Meninger; Jose Oscar Mur-Miranda; Rajeevan Amirtharajah; Anantha Chandrakasan; Jeffrey Lang

1999-01-01

381

Energy harvesting from electric power lines employing the Halbach arrays

NASA Astrophysics Data System (ADS)

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.

He, Wei; Li, Ping; Wen, Yumei; Zhang, Jitao; Lu, Caijiang; Yang, Aichao

2013-10-01

382

Real World Testing Of A Piezoelectric Rotational Energy Harvester For Human Motion

NASA Astrophysics Data System (ADS)

Harvesting energy from human motion is challenging because the frequencies are generally low and random compared to industrial machinery that vibrates at much higher frequencies. One of the most promising and popular strategies to overcome this is frequency up-conversion. The transducing element is actuated at its optimal frequency of operation, higher than the source excitation frequency, through some kind of catch and release mechanism. This is beneficial for efficient power generation. Such devices have now been investigated for a few years and this paper takes a previously introduced piezoelectric rotational harvester, relying on beam plucking for the energy conversion, to the next step by testing the device during a half marathon race. The prototype and data acquisition system are described in detail and the experimental results presented. A comparison of the input excitation, based on an accelerometer readout, and the output voltage of the piezoelectric beam, recorded at the same time, confirm the successful implementation of the system. For a device functional volume of 1.85 cm3, a maximum power output of 7 ?W was achieved when the system was worn on the upper arm. However, degradation of the piezoelectric material meant that the performance dropped rapidly from this initial level; this requires further research. Furthermore, the need for intermediate energy storage solutions is discussed, as human motion harvesters only generate power as long as the wearer is actually moving.

Pillatsch, P.; Yeatman, E. M.; Holmes, A. S.

2013-12-01

383

Comparison of Piezoelectric Energy Harvesting Devices for Recharging Batteries

Piezoelectric materials can be used as a means of transforming ambient vibrations into electrical energy that can then be stored and used to power other devices. With the recent surge of microscale devices, piezoelectric power generation can provide a convenient alternative to traditional power sources used to operate certain types of sensors\\/actuators, telemetry, and MEMS devices. However, the energy produced

Henry A. Sodano; Daniel J. Inman

2005-01-01

384

Harvesting Energy from the Marine Sediment-Water Interface

Harvesting Energy from the Marine Sediment-Water Interface C L A R E E . R E I M E R S * College D E R * Center for Biomolecular Science and Engineering - Code 6900, Naval Research Laboratory, Virginia 22308 W E I W A N G Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick

Rosen, I. Gary

385

Myocardial Cell Pattern on Piezoelectric Nanofiber Mats for Energy Harvesting

NASA Astrophysics Data System (ADS)

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.

Liu, X.; Wang, X.; Zhao, H.; Du, Y.

2014-11-01

386

Experimental investigations on energy harvesting performance of dielectric elastomers

NASA Astrophysics Data System (ADS)

In this paper, the emerging technology of energy harvesting based on dielectric elastomers (DE), a new type of functional materials belonging to the family of Electroactive Polymers (EAPs), is presented with emphasis on its performance characteristics and some key influencing factors. At first, on the basic principle of DE energy harvesting, the effects of some control parameters are theoretically analyzed under certain mechanical and electrical constraints. Then, a type of annular DE generator using the commercial elastomers of VHB 4910 (3M, USA), is specially designed and fabricated. A series of experimental tests for the device's energy harvesting performance are implemented at different pre-stretch ratios, stretch amplitudes (displacements), and bias voltages in the constant charge (open-circuit) condition. The experiment results demonstrate the associated influence laws of the above control parameters on the performance of the DE generator, and have good consistent with those obtained from the theoretical analysis. This study is expected to provide a helpful guidance for the design and operation of practical DE energy harvesting devices/systems.

Wang, Yongquan; Liu, Xuejing; Xue, Huanhuan; Chen, Hualing; Jia, Shuhai

2014-03-01

387

Online Fault Detection and Tolerance for Photovoltaic Energy Harvesting Systems

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

Pedram, Massoud

388

Engineered biomimicry for harvesting solar energy: a bird's eye view

All three methodologies of engineered biomimicry – bioinspiration, biomimetics, and bioreplication – are represented in current research on harvesting solar energy. Both processes and porous surfaces inspired by plants and certain marine animals, respectively, are being investigated for solar cells. Whereas dye-sensitized solar cells deploy artificial photosynthesis, bioinspired nanostructuring of materials in solar cells improves performance. Biomimetically textured coatings for

Raúl J. Martín-Palma; Akhlesh Lakhtakia

2012-01-01

389

Energy harvesting using AC machines with high effective pole count

In this thesis, ways to improve the power conversion of rotating generators at low rotor speeds in energy harvesting applications were investigated. One method is to increase the pole count, which increases the generator back-emf without also increasing the I2R losses, thereby increasing both torque density and conversion efficiency. One machine topology that has a high effective pole count is

Richard Theodore Geiger

2010-01-01

390

Energy harvesting using AC machines with high effective pole count

In this paper, we investigate ways to improve the power conversion of small, rotating, permanent magnet AC machines at low rotor speeds in energy harvesting applications. One method is to increase the pole count, which increases the generator back-emf without also increasing the I2R losses, thereby increasing both torque density and conversion efficiency. One machine topology that has a high

Richard Geiger; Heath Hofmann

2008-01-01

391

Delay Optimal Scheduling for Energy Harvesting Based Communications

always waits for harvest energy. To overcome this, the source would naturally resort to the reliable waiting time and power consumption on the reliable supply (which may require payment). In this paper, we system. By a two-dimensional Markov chain modeling, we give an analysis on the average queuing delay

Dai, Huaiyu

392

Amplified energy harvester from footsteps: design, modeling, and experimental analysis

NASA Astrophysics Data System (ADS)

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.

Wang, Ya; Chen, Wusi; Guzman, Plinio; Zuo, Lei

2014-04-01

393

A System Design Approach for Unattended Solar Energy Harvesting Supply

Remote devices, such as sensors and communications devices, require continuously available power. In many applications, conventional approaches are too expensive, too large, or unreliable. For short-term needs, primary batteries may be used. However, they do not scale up well for long-term installations. Instead, energy harvesting methods must be used. Here, a system design approach is introduced that results in a

Jonathan W. Kimball; Brian T. Kuhn; Robert S. Balog

2009-01-01

394

Energy harvesting for the implantable biomedical devices: issues and challenges.

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

Hannan, Mahammad A; Mutashar, Saad; Samad, Salina A; Hussain, Aini

2014-01-01

395

Light-harvesting materials: Soft support for energy conversion

NASA Astrophysics Data System (ADS)

To convert solar energy into viable fuels, coupling light-harvesting materials to catalysts is a crucial challenge. Now, the combination of an organic supramolecular hydrogel and a non-precious metal catalyst has been demonstrated to be effective for photocatalytic H2 production.

Stolley, Ryan M.; Helm, Monte L.

2014-11-01

396

An integrated approach to energy harvester modeling and performance optimization

This paper proposes an integrated approach to energy harvester (EH) modeling and performance optimization where the complete mixed physical-domain EH (micro generator, voltage booster, storage element and load) can be modeled and optimized. We show that electrical equivalent models of the micro generator are inadequate for accurate prediction of the voltage booster's performance. Through the use of hardware description language

Leran Wang; Tom J. Kazmierski; Bashir M. Al-Hashimi; Steve P. Beeby; Russel N. Torah

2007-01-01

397

Lifetime maximization in mobile sensor networks with energy harvesting

This paper investigates mobility strategies of mo- bile robots to improve the lifetime of a mobile sensor net- work with energy harvesting capability. The network lifetime problem is formulated as a nonlinear non-convex optimization problem, which is solved distributively by a series of convex approximations and a novel saddle-point computation algo- rithm. The convergence of the proposed method is guaranteed.

Shengwei Yu; C. S. George Lee

2011-01-01

398

A statistical linearization approach to optimal nonlinear energy harvesting

NASA Astrophysics Data System (ADS)

In this study, an extension of linear-quadratic-Gaussian (LQG) control theory is used to determine the optimal state feedback controller for a nonlinear energy harvesting system that is driven by a stochastic disturbance. Specifically, the energy harvester is a base-excited single-degree-of-freedom (SDOF) resonant oscillator with an electromagnetic transducer embedded between the ground and moving mass. The electromagnetic transducer used to harvest energy from the SDOF oscillator introduces a nonlinear Coulomb friction force into the system, which must be accounted for in the design of the controller. As such, the development of the optimal controller for this system is based on statistical linearization, whereby the Coulomb friction force is replaced by an equivalent linear viscous damping term, which is calculated from the stationary covariance of the closed-loop system. It is shown that the covariance matrix and optimal feedback gain matrix can be computed by implementing an iterative algorithm involving linear matrix inequalities (LMIs). Simulation results are presented for the SDOF energy harvester in which the performance of the optimal state feedback control law is compared to the performance of the optimal static admittance over a range of disturbance bandwidths.

Cassidy, Ian L.; Scruggs, Jeffrey T.

2012-04-01

399

NASA Astrophysics Data System (ADS)

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.

Yang, Zhengbao; Zhu, Yang; Zu, Jean

2015-02-01

400

Flexible hybrid energy cell for simultaneously harvesting thermal, mechanical, and solar energies.

We report the first flexible hybrid energy cell that is capable of simultaneously or individually harvesting thermal, mechanical, and solar energies to power some electronic devices. For having both the pyroelectric and piezoelectric properties, a polarized poly(vinylidene fluoride) (PVDF) film-based nanogenerator (NG) was used to harvest thermal and mechanical energies. Using aligned ZnO nanowire arrays grown on the flexible polyester (PET) substrate, a ZnO-poly(3-hexylthiophene) (P3HT) heterojunction solar cell was designed for harvesting solar energy. By integrating the NGs and the solar cells, a hybrid energy cell was fabricated to simultaneously harvest three different types of energies. With the use of a Li-ion battery as the energy storage, the harvested energy can drive four red light-emitting diodes (LEDs). PMID:23199138

Yang, Ya; Zhang, Hulin; Zhu, Guang; Lee, Sangmin; Lin, Zong-Hong; Wang, Zhong Lin

2013-01-22

401

NASA Astrophysics Data System (ADS)

There has been growing interest in enabling wireless health and usage monitoring for rotorcraft applications, such as helicopter rotor systems. Large dynamic loads and acceleration fluctuations available in these environments make the implementation of vibration-based piezoelectric energy harvesters a very promising choice. However, such extreme loads transmitted to the harvester can also be detrimental to piezoelectric laminates and overall system reliability. Particularly flexible resonant cantilever configurations tuned to match the dominant excitation frequency can be subject to very large deformations and failure of brittle piezoelectric laminates due to excessive bending stresses at the root of the harvester. Design of resonant piezoelectric energy harvesters for use in these environments require nonlinear electroelastic dynamic modeling and strength-based analysis to maximize the power output while ensuring that the harvester is still functional. This paper presents a mathematical framework to design and analyze the dynamics of nonlinear flexible piezoelectric energy harvesters under large base acceleration levels. A strength-based limit is imposed to design the piezoelectric energy harvester with a proof mass while accounting for material, geometric, and dissipative nonlinearities, with a focus on two demonstrative case studies having the same linear fundamental resonance frequency but different overhang length and proof mass values. Experiments are conducted at different excitation levels for validation of the nonlinear design approach proposed in this work. The case studies in this work reveal that harvesters exhibiting similar behavior and power generation performance at low excitation levels (e.g. less than 0.1g) can have totally different strength-imposed performance limitations under high excitations (e.g. above 1g). Nonlinear modeling and strength-based design is necessary for such excitation levels especially when using resonant cantilevers with no geometric constraint.

Leadenham, Stephen; Erturk, Alper

2014-04-01

402

Thermal energy harvesters with piezoelectric or electrostatic transducer

NASA Astrophysics Data System (ADS)

This paper describes the idea of the energy harvester which converts thermal gradient present in environment into electricity. Two kinds of such devices are proposed and their prototypes are shown and discussed. The main parts of harvesters are bimetallic spring, piezoelectric transducer or electrostatic transducer with electret. The applied piezomembrane was commercial available product but electrets was made by authors. In the paper a fabrication procedure of electrets formed by the corona discharge process is described. Devices were compared in terms of generated power, charging current, and the voltage across a storage capacitor.

Prokaryn, Piotr; Doma?ski, Krzysztof; Marchewka, Micha?; Tomaszewski, Daniel; Grabiec, Piotr; Puscasu, Onoriu; Monfray, Stéphane; Skotnicki, Thomas

2014-08-01

403

Industrial harvesting of olive tree pruning residue for energy biomass.

In Mediterranean countries, olive tree pruning residue represents an abundant source of energy biomass, still largely unexploited for lack of cost-effective harvesting technology. The authors tested two industrial pruning harvesters, capable of overcoming the limits of lighter units appeared in the past years. One of the machines was designed for application to a powerful farm tractor, whereas the other was a self-propelled dedicated harvester. Data were collected from 10 operations, covering a total of 69 hectares and producing over 190 tonnes of wood fuel. Recorded productivity varied between 3 and 9 tonnes per scheduled machine hour (SMH), or 2-7 oven dry tonnes (odt) SMH(-1). Harvesting cost varied from 17 to 52 euro t(-1), with an average value of 28 euro t(-1): these values correspond, respectively to 22, 70 and 40 euro odt(-1). This compares very favourably with the average 1-1.5 ton SMH(-1) offered by lighter commercial units. Productivity was related to residue density, row length and forwarding distance. Mechanical availability was high and over 90%, for both machines. The authors also developed a simple deterministic model capable of predicting harvesting productivity and cost, as a function of significant site and economic conditions. The model can also be used to determine the break-even utilization level, below which the operational flexibility of a tractor-mounted operation becomes preferable to the higher productivity of a specialised unit. PMID:19740650

Spinelli, Raffaele; Picchi, Gianni

2010-01-01

404

An effective multi-source energy harvester for low power applications

Small autonomous embedded systems powered by means of energy harvesting techniques, have gained momentum in industry and research. This paper presents a simple, yet effective and complete energy harvesting solution which permits the exploitation of an arbitrary number of ambient energy sources. The proposed modular architecture collects energy from each of the connected harvesting subsystems in a concurrent and independent

Davide Carli; Davide Brunelli; Luca Benini; Massimiliano Ruggeri

2011-01-01

405

Energy harvesting measurements from stall flutter limit cycle oscillations

NASA Astrophysics Data System (ADS)

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.

Chen, Jasper; Dhanushkodi, Adit; Lee, Christopher L.

2014-04-01

406

Vibrational energy redistribution in glyoxal following internal conversion

Vibrational energy redistribution in glyoxal following internal conversion R. Naaman,a) D. M 4 June 1979; accepted 10 August 1979) The vibrational redistribution of energy following internal that combination bands of low quanta of vibrations are the accepting levels in the internal conversion process

Zare, Richard N.

407

Near-field thermodynamics: Useful work, efficiency, and energy harvesting

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.

Latella, Ivan, E-mail: ilatella@ffn.ub.edu; Pérez-Madrid, Agustín, E-mail: agustiperezmadrid@ub.edu [Departament de Física Fonamental, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain); Lapas, Luciano C., E-mail: luciano.lapas@pq.cnpq.br [Universidade Federal da Integração Latino-Americana, Caixa Postal 2067, 85867-970 Foz do Iguaçu (Brazil); Miguel Rubi, J., E-mail: mrubi@ub.edu [Departament de Física Fonamental, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain); Department of Chemistry, Imperial College London, SW7 2AZ London (United Kingdom)

2014-03-28

408

Energy harvesting with piezoelectric circular membrane under pressure loading

NASA Astrophysics Data System (ADS)

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.

Mo, Changki; Davidson, Joseph; Clark, William W.

2014-04-01

409

Harvesting the Sun's Energy with Antennas

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.

INL

2008-05-28

410

Harvesting the Sun's Energy with Antennas

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.

INL

2009-09-01

411

Seebeck Nanoantennas for Infrared Detection and Energy Harvesting Applications

In this letter we introduce a new type of infrared sensor, based on thermocouple nanoantennas, which enables the energy detection and gathering in the mid-infrared region. The proposed detector combines the Seebeck effect, as a transduction mechanism, with the functionalities of the optical antennas for optical sensing. By using finite-element numerical simulations we evaluate the performance and optical-to-electrical conversion efficiency of the proposed device, unveiling its potential for optical sensing and energy harvesting applications.

Briones, Edgar; Martinez-Anton, J C; Cuadrado, Alexander; McMurtry, Stefan; Hehn, Michel; Montaigne, François; Alda, Javier; González, Javier

2014-01-01

412

Perspectives on Energy-Harvesting Wireless Sensor Networks

\\u000a An energy-harvesting wireless sensor network (EHWSN) is an application-specific collection of wirelessly connected, highly\\u000a resource-constrained radios, which are independent and capable of sensing, storing, processing and forwarding data, and capable\\u000a of extracting energy from their environment. The network typically will have a connection to at least one less-constrained\\u000a “Gateway” or “Sink” radio that is connected to the internet either wirelessly

Mary Ann Ingram; Lakshmi Thanayankizil; Jin Woo Jung; Aravind Kailas

413

Light-harvesting materials: Soft support for energy conversion

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

Stolley, Ryan M.; Helm, Monte L.

2014-11-10

414

Actuators and Energy Harvesters Based on Electrostrictive Elastomeric Nanocomposites

\\u000a Research and development efforts devoted to electro active polymers (EAPs) are being actively undertaken today due to the numerous advantages of these materials. Moreover, from the viewpoint\\u000a of world-wide ecological tendencies, renewable and clean energy sources turn the heads of not only researchers. The harvesting or scavenging of ambient energy constitutes an important alternative stage. Among various specifics of EAPs,

Kaori Yuse; Pierre-Jean Cottinet; Daniel Guyomar

415

A miniature airflow energy harvester from piezoelectric materials

NASA Astrophysics Data System (ADS)

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