Method and system for a gas tube-based current source high voltage direct current transmission system

DOEpatents

She, Xu; Chokhawala, Rahul Shantilal; Bray, James William; Sommerer, Timothy John; Zhou, Rui; Zhang, Di

2017-08-29

A high-voltage direct-current (HVDC) transmission system includes an alternating current (AC) electrical source and a power converter channel that includes an AC-DC converter electrically coupled to the electrical source and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and the DC-AC inverter each include a plurality of legs that includes at least one switching device. The power converter channel further includes a commutating circuit communicatively coupled to one or more switching devices. The commutating circuit is configured to "switch on" one of the switching devices during a first portion of a cycle of the H-bridge switching circuits and "switch off" the switching device during a second portion of the cycle of the first and second H-bridge switching circuits.

Power Strategy in DC/DC Converters to Increase Efficiency of Electrical Stimulators.

PubMed

Aqueveque, Pablo; Acuña, Vicente; Saavedra, Francisco; Debelle, Adrien; Lonys, Laurent; Julémont, Nicolas; Huberland, François; Godfraind, Carmen; Nonclercq, Antoine

2016-06-13

Power efficiency is critical for electrical stimulators. Battery life of wearable stimulators and wireless power transmission in implanted systems are common limiting factors. Boost DC/DC converters are typically needed to increase the supply voltage of the output stage. Traditionally, boost DC/DC converters are used with fast control to regulate the supply voltage of the output. However, since stimulators are acting as current sources, such voltage regulation is not needed. Banking on this, this paper presents a DC/DC conversion strategy aiming to increase power efficiency. It compares, in terms of efficiency, the traditional use of boost converters to two alternatives that could be implemented in future hardware designs.

Direct current uninterruptible power supply method and system

DOEpatents

Sinha, Gautam

2003-12-02

A method and system are described for providing a direct current (DC) uninterruptible power supply with the method including, for example: continuously supplying fuel to a turbine; converting mechanical power from the turbine into alternating current (AC) electrical power; converting the AC electrical power to DC power within a predetermined voltage level range; supplying the DC power to a load; and maintaining a DC load voltage within the predetermined voltage level range by adjusting the amount of fuel supplied to the turbine.

Onboard power line conditioning system for an electric or hybrid vehicle

DOEpatents

Kajouke, Lateef A.; Perisic, Milun

2016-06-14

A power line quality conditioning system for a vehicle includes an onboard rechargeable direct current (DC) energy storage system and an onboard electrical system coupled to the energy storage system. The energy storage system provides DC energy to drive an electric traction motor of the vehicle. The electrical system operates in a charging mode such that alternating current (AC) energy from a power grid external to the vehicle is converted to DC energy to charge the DC energy storage system. The electrical system also operates in a vehicle-to-grid power conditioning mode such that DC energy from the DC energy storage system is converted to AC energy to condition an AC voltage of the power grid.

SNAP 10A ESTIMATED ELECTRICAL CHARACTERISTICS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cooper, J.C.

1961-06-01

The electrical power characteristics of a SNAP 10A converter are estimated for given fractions of power degradation. Graphs are included showing the power characteristics for instantaneous transients from stabilized operation at the maximum efficiency point, and after system temperature stabilization at the operating point. Open-circuit emf's of the converter are estimated for instantaneous and temperature-stabilized cases. (D.L.C.)

Parametric study of laser photovoltaic energy converters

NASA Technical Reports Server (NTRS)

Walker, G. H.; Heinbockel, J. H.

1987-01-01

Photovoltaic converters are of interest for converting laser power to electrical power in a space-based laser power system. This paper describes a model for photovoltaic laser converters and the application of this model to a neodymium laser silicon photovoltaic converter system. A parametric study which defines the sensitivity of the photovoltaic parameters is described. An optimized silicon photovoltaic converter has an efficiency greater than 50 percent for 1000 W/sq cm of neodymium laser radiation.

Improved lifetime of chitosan film in converting water vapor to electrical power by adding carboxymethyl cellulose

NASA Astrophysics Data System (ADS)

Nasution, T. I.; Balyan, M.; Nainggolan, I.

2018-02-01

A Water vapor cell based on chitosan film has been successfully fabricated in film form to convert water vapor to electrical power. In order to improve the lifetime of water vapor cell, Carboxymethyl Cellulose (CMC) was added into 1% chitosan solution within concentration variations of 0.01, 0.05, 0.1 and 0.5%. The result showed that the lifetime of water vapor cell increased higher by adding the higher concentration of Carboxymethyl cellulose. The highest lifetime was evidenced by adding 0.5%CMC which maintained for 48 weeks. However, the average electrical power became lower to 4.621 µW. This electrical power lower than the addition of 0.1%CMC which maintained for 5.167 µW. While, the lifetime of chitosan-0.1%CMC film of 44 weeks is shorter compared to chitosan-0.5%CMC film. Based on FTIR characterization, it was founded that the chitosan structure did not change until the addition of 0.1%CMC. This caused the electrical power of water vapor cell degenerated. Therefore, chitosan-0.5%CMC film has excellent lifetime in converting water vapor to electrical power.

Pilot solar power plant

NASA Astrophysics Data System (ADS)

Wolf, D.

A fully functionally efficient solar-thermal power plant (10 kW electric) was built. The operating principle of thermomechanical conversion of solar energy into mechanical or electrical energy is presented. The equipment is completely automatic. Flat plate collectors absorb solar energy and convert it into heat which is transmitted by water to a heat exchanger. A closed cycle machine uses the heat to boil a working fluid (C2C12F4). A screw, powered by gas expansion in the working fluid, converts mechanical energy into electrical energy.

Power electronic interface circuits for batteries and ultracapacitors in electric vehicles and battery storage systems

DOEpatents

King, Robert Dean; DeDoncker, Rik Wivina Anna Adelson

1998-01-01

A method and apparatus for load leveling of a battery in an electrical power system includes a power regulator coupled to transfer power between a load and a DC link, a battery coupled to the DC link through a first DC-to-DC converter and an auxiliary passive energy storage device coupled to the DC link through a second DC-to-DC converter. The battery is coupled to the passive energy storage device through a unidirectional conducting device whereby the battery can supply power to the DC link through each of the first and second converters when battery voltage exceeds voltage on the passive storage device. When the load comprises a motor capable of operating in a regenerative mode, the converters are adapted for transferring power to the battery and passive storage device. In this form, resistance can be coupled in circuit with the second DC-to-DC converter to dissipate excess regenerative power.

Power electronic interface circuits for batteries and ultracapacitors in electric vehicles and battery storage systems

DOEpatents

King, R.D.; DeDoncker, R.W.A.A.

1998-01-20

A method and apparatus for load leveling of a battery in an electrical power system includes a power regulator coupled to transfer power between a load and a DC link, a battery coupled to the DC link through a first DC-to-DC converter and an auxiliary passive energy storage device coupled to the DC link through a second DC-to-DC converter. The battery is coupled to the passive energy storage device through a unidirectional conducting device whereby the battery can supply power to the DC link through each of the first and second converters when battery voltage exceeds voltage on the passive storage device. When the load comprises a motor capable of operating in a regenerative mode, the converters are adapted for transferring power to the battery and passive storage device. In this form, resistance can be coupled in circuit with the second DC-to-DC converter to dissipate excess regenerative power. 8 figs.

Electrical system architecture having high voltage bus

DOEpatents

Hoff, Brian Douglas [East Peoria, IL; Akasam, Sivaprasad [Peoria, IL

2011-03-22

An electrical system architecture is disclosed. The architecture has a power source configured to generate a first power, and a first bus configured to receive the first power from the power source. The architecture also has a converter configured to receive the first power from the first bus and convert the first power to a second power, wherein a voltage of the second power is greater than a voltage of the first power, and a second bus configured to receive the second power from the converter. The architecture further has a power storage device configured to receive the second power from the second bus and deliver the second power to the second bus, a propulsion motor configured to receive the second power from the second bus, and an accessory motor configured to receive the second power from the second bus.

Making the Most of Waste Energy

NASA Technical Reports Server (NTRS)

2005-01-01

The Thermo-Mechanical Systems Branch at NASA s Glenn Research Center is responsible for planning and conducting research efforts to advance thermal systems for space, aerospace, and non-aerospace applications. Technological areas pertain to solar and thermal energy conversion. For example, thermo-mechanical systems researchers work with gas (Stirling) and liquid/vapor (Rankine) systems that convert thermal energy to electrical power, as well as solar dynamic power systems that concentrate sunlight to electrical power. The branch s development of new solar and thermal energy technologies is propelling NASA s missions deep into unfamiliar territories of space. Solar dynamic power systems are actively improving the health of orbiting satellites, giving them longer life and a stronger radiation tolerance, thus, creating less need for on-orbit maintenance. For future missions, NASA may probe even deeper into the mysterious cosmos, with the adoption of highly efficient thermal energy converters that have the potential to serve as the source of onboard electrical power for satellites and spacecraft. Research indicates that these thermal converters can deliver up to 5 times as much power as radioisotope thermoelectric generators in use today, for the same amount of radioisotope. On Earth, energy-converting technologies associated with NASA s Thermo-Mechanical Systems Branch are being used to recover and transform low-temperature waste heat into usable electric power, with a helping hand from NASA.

More Efficient Power Conversion for EVs: Gallium-Nitride Advanced Power Semiconductor and Packaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2010-02-01

Broad Funding Opportunity Announcement Project: Delphi is developing power converters that are smaller and more energy efficient, reliable, and cost-effective than current power converters. Power converters rely on power transistors which act like a very precisely controlled on-off switch, controlling the electrical energy flowing through an electrical circuit. Most power transistors today use silicon (Si) semiconductors. However, Delphi is using semiconductors made with a thin layer of gallium-nitride (GaN) applied on top of the more conventional Si material. The GaN layer increases the energy efficiency of the power transistor and also enables the transistor to operate at much higher temperatures,more » voltages, and power-density levels compared to its Si counterpart. Delphi is packaging these high-performance GaN semiconductors with advanced electrical connections and a cooling system that extracts waste heat from both sides of the device to further increase the device’s efficiency and allow more electrical current to flow through it. When combined with other electronic components on a circuit board, Delphi’s GaN power transistor package will help improve the overall performance and cost-effectiveness of HEVs and EVs.« less

FEM analysis of an single stator dual PM rotors axial synchronous machine

NASA Astrophysics Data System (ADS)

Tutelea, L. N.; Deaconu, S. I.; Popa, G. N.

2017-01-01

The actual e - continuously variable transmission (e-CVT) solution for the parallel Hybrid Electric Vehicle (HEV) requires two electric machines, two inverters, and a planetary gear. A distinct electric generator and a propulsion electric motor, both with full power converters, are typical for a series HEV. In an effort to simplify the planetary-geared e-CVT for the parallel HEV or the series HEV we hereby propose to replace the basically two electric machines and their two power converters by a single, axial-air-gap, electric machine central stator, fed from a single PWM converter with dual frequency voltage output and two independent PM rotors. The proposed topologies, the magneto-motive force analysis and quasi 3D-FEM analysis are the core of the paper.

Electric converters of electromagnetic strike machine with battery power

NASA Astrophysics Data System (ADS)

Usanov, K. M.; Volgin, A. V.; Kargin, V. A.; Moiseev, A. P.; Chetverikov, E. A.

2018-03-01

At present, the application of pulse linear electromagnetic engines to drive strike machines for immersion of rod elements into the soil, strike drilling of shallow wells, dynamic probing of soils is recognized as quite effective. The pulse linear electromagnetic engine performs discrete consumption and conversion of electrical energy into mechanical work. Pulse dosing of a stream transmitted by the battery source to the pulse linear electromagnetic engine of the energy is provided by the electrical converter. The electric converters with the control of an electromagnetic strike machine as functions of time and armature movement, which form the unipolar supply pulses of voltage and current necessary for the normal operation of a pulse linear electromagnetic engine, are proposed. Electric converters are stable in operation, implement the necessary range of output parameters control determined by the technological process conditions, have noise immunity and automatic disconnection of power supply in emergency modes.

Systems and methods for an integrated electrical sub-system powered by wind energy

DOEpatents

Liu, Yan [Ballston Lake, NY; Garces, Luis Jose [Niskayuna, NY

2008-06-24

Various embodiments relate to systems and methods related to an integrated electrically-powered sub-system and wind power system including a wind power source, an electrically-powered sub-system coupled to and at least partially powered by the wind power source, the electrically-powered sub-system being coupled to the wind power source through power converters, and a supervisory controller coupled to the wind power source and the electrically-powered sub-system to monitor and manage the integrated electrically-powered sub-system and wind power system.

Power Converters Maximize Outputs Of Solar Cell Strings

NASA Technical Reports Server (NTRS)

Frederick, Martin E.; Jermakian, Joel B.

1993-01-01

Microprocessor-controlled dc-to-dc power converters devised to maximize power transferred from solar photovoltaic strings to storage batteries and other electrical loads. Converters help in utilizing large solar photovoltaic arrays most effectively with respect to cost, size, and weight. Main points of invention are: single controller used to control and optimize any number of "dumb" tracker units and strings independently; power maximized out of converters; and controller in system is microprocessor.

Static Converter for High Energy Utilization, Modular, Small Nuclear Power Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

El-Genk, Mohamed S.; Tournier, Jean-Michel P.

2002-07-01

This paper presents and analyzes the performance of high efficiency, high total energy utilization, static converters, which could be used in conjunction with small nuclear reactor plants in remote locations and in undersea applications, requiring little or no maintenance. The converters consist of a top cycle of Alkali Metal Thermal-to-Electric Conversion (AMTEC) units and PbTe thermoelectric (TE) bottom cycle. In addition to converting the reactor thermal power to electricity at 1150 K or less, at a thermodynamic efficiency in the low to mid thirties, the heat rejection from the TE bottom cycle could be used for space heating, industrial processing,more » or sea water desalination. The results indicated that for space heating applications, where the rejected thermal power from the TE bottom cycle is removed by natural convection of ambient air, a total utilization of the reactor thermal power of > 80% is possible. When operated at 1030 K, potassium AMTEC/TE converters are not only more efficient than the sodium AMTEC/TE converters but produce more electrical power. The present analysis showed that a single converter could be sized to produce up to 100 kWe and 70 kWe, for the Na-AMTEC/TE units when operating at 1150 K and the K-AMTEC/TE units when operating at 1030 K, respectively. Such modularity is an added advantage to the high-energy utilization of the present AMTEC/TE converters. (authors)« less

A Fully Directional Universal Power Electronic Interface for EV, HEV, and PHEV Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Onar, Omer C

2012-01-01

This study focuses on a universal power electronic interface that can be utilized in any type of the electric vehicles, hybrid electric vehicles, and plug-in hybrid electric vehicles (PHEVs). Basically, the proposed converter interfaces the energy storage device of the vehicle with the motor drive and the external charger, in case of PHEVs. The proposed converter is capable of operating in all directions in buck or boost modes with a noninverted output voltage (positive output voltage with respect to the input) and bidirectional power flow.

Experimental Investigations from the Operation of a 2 Kw Brayton Power Conversion Unit and a Xenon Ion Thruster

NASA Technical Reports Server (NTRS)

Mason, Lee; Birchenough, Arthur; Pinero, Luis

2004-01-01

A 2 kW Brayton Power Conversion Unit (PCU) and a xenon ion thruster were integrated with a Power Management and Distribution (PMAD) system as part of a Nuclear Electric Propulsion (NEP) Testbed at NASA's Glenn Research Center. Brayton converters and ion thrusters are potential candidates for use on future high power NEP missions such as the proposed Jupiter Icy Moons Orbiter (JIMO). The use of existing lower power test hardware provided a cost-effective means to investigate the critical electrical interface between the power conversion system and ion propulsion system. The testing successfully demonstrated compatible electrical operations between the converter and the thruster, including end-to-end electric power throughput, high efficiency AC to DC conversion, and thruster recycle fault protection. The details of this demonstration are reported herein.

Experimental Investigation from the Operation of a 2 kW Brayton Power Conversion Unit and a Xenon Ion Thruster

NASA Technical Reports Server (NTRS)

Hervol, David; Mason, Lee; Birchenough, Art; Pinero, Luis

2004-01-01

A 2kW Brayton Power Conversion Unit (PCU) and a xenon ion thruster were integrated with a Power Management and Distribution (PMAD) system as part of a Nuclear Electric Propulsion (NEP) Testbed at NASA's Glenn Research Center. Brayton Converters and ion thrusters are potential candidates for use on future high power NEP mission such as the proposed Jupiter Icy Moons Orbiter (JIMO). The use of a existing lower power test hardware provided a cost effective means to investigate the critical electrical interface between the power conversion system and the propulsion system. The testing successfully demonstrated compatible electrical operations between the converter and the thruster, including end-to-end electric power throughput, high efficiency AC to DC conversion, and thruster recycle fault protection. The details of this demonstration are reported herein.

Design and characterization of a novel power over fiber system integrating a high power diode laser

NASA Astrophysics Data System (ADS)

Perales, Mico; Yang, Mei-huan; Wu, Cheng-liang; Hsu, Chin-wei; Chao, Wei-sheng; Chen, Kun-hsein; Zahuranec, Terry

2017-02-01

High power 9xx nm diode lasers along with MH GoPower's (MHGP's) flexible line of Photovoltaic Power Converters (PPCs) are spurring high power applications for power over fiber (PoF), including applications for powering remote sensors and sensors monitoring high voltage equipment, powering high voltage IGBT gate drivers, converters used in RF over Fiber (RFoF) systems, and system power applications, including powering UAVs. In PoF, laser power is transmitted over fiber, and is converted to electricity by photovoltaic cells (packaged into Photovoltaic Power Converters, or PPCs) which efficiently convert the laser light. In this research, we design a high power multi-channel PoF system, incorporating a high power 976 nm diode laser, a cabling system with fiber break detection, and a multichannel PPC-module. We then characterizes system features such as its response time to system commands, the PPC module's electrical output stability, the PPC-module's thermal response, the fiber break detection system response, and the diode laser optical output stability. The high power PoF system and this research will serve as a scalable model for those interested in researching, developing, or deploying a high power, voltage isolated, and optically driven power source for high reliability utility, communications, defense, and scientific applications.

Space power plants

NASA Astrophysics Data System (ADS)

Khudyakov, S. A.

1985-05-01

Power generators in space are examined. A semiconducting photoelectric converter (FEP) which converts the energy of solar radiation directly into electrical energy is discussed. The operating principle of an FEP is based on the interaction of solar light with a crystal semiconductor, in the process of which the photons produce free electrons, carriers of an electrical charge, in the crystal. Areas with a strong electrical field created specially under the effect of the p-n junction trap the freed electrons and divide them in such a fashion that a current and corresponding electrical power appear in the load circuit. The absorption of light in metals and pure semiconductors is outlined.

Method and system for a gas tube switch-based voltage source high voltage direct current transmission system

DOE Office of Scientific and Technical Information (OSTI.GOV)

She, Xu; Chokhawala, Rahul Shantilal; Zhou, Rui

A voltage source converter based high-voltage direct-current (HVDC) transmission system includes a voltage source converter (VSC)-based power converter channel. The VSC-based power converter channel includes an AC-DC converter and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and a DC-AC inverter include at least one gas tube switching device coupled in electrical anti-parallel with a respective gas tube diode. The VSC-based power converter channel includes a commutating circuit communicatively coupled to one or more of the at least one gas tube switching devices. The commutating circuit is configured to "switch on" a respective one of themore » one or more gas tube switching devices during a first portion of an operational cycle and "switch off" the respective one of the one or more gas tube switching devices during a second portion of the operational cycle.« less

Research of frequency converters energy characteristics of drilling rigs

NASA Astrophysics Data System (ADS)

Vasiliev, B. Y.; Kalashnikov, O. V.; Oleynikova, A. M.; Ivanovsky, A. I.; Grudinin, N. N.

2017-10-01

The investigation deals with multi-motor electric drives with frequency converters of various structures: with a common converter, with an individual converter, with a multi-inverter frequency converter. Their shortcomings and advantages were analyzed and there were drawn conclusions about the expediency of using each structure. Expediency of using multi-inverter frequency converters with an active frond end was shown to ensure the highest power characteristics of multi-motor electric drives of drilling rigs’ main mechanisms.

A comparative study of electric power distribution systems for spacecraft

NASA Technical Reports Server (NTRS)

Stuart, Thomas A.; King, Roger J.

1990-01-01

The electric power distribution systems for spacecraft are compared concentrating on two interrelated issues: the choice between dc and high frequency ac, and the converter/inverter topology to be used at the power source. The relative merits of dc and ac distribution are discussed. Specific converter and inverter topologies are identified and analyzed in detail for the purpose of detailed comparison. Finally, specific topologies are recommended for use in dc and ac systems.

Particle-In-Cell Simulations of a Thermionic Converter

NASA Astrophysics Data System (ADS)

Clark, S. E.

2017-12-01

Simulations of thermionic converters are presented where cesium is used as a work function reducing agent in a nano-fabricated triode configuration. The cathode and anode are spaced on the order of 100 μm, and the grid structure has features on the micron scale near the anode. The hot side is operated near 1600 K, the cold side near 600 K, and the converter has the potential to convert heat to DC electrical current upwards of 20% efficiency. Affordable and robust thermionic converters have the potential to displace century old mechanical engines and turbines as a primary means of electrical power generation in the near future. High efficiency converters that operate at a small scale could be used to generate power locally and alleviate the need for large scale power transmission systems. Electron and negative cesium ion back emission from the anode are considered, as well as device longevity and fabrication feasibility.

Particle-In-Cell Simulations of a Thermionic Converter

NASA Astrophysics Data System (ADS)

Clark, Stephen

2017-10-01

Simulations of thermionic converters are presented where cesium is used as a work function reducing agent in a nano-fabricated triode configuration. The cathode and anode are spaced on the order of 100 μm, and the grid structure has features on the micron scale near the anode. The hot side is operated near 1600 K, the cold side near 600 K, and the converter has the potential to convert heat to DC electrical current upwards of 20% efficiency. Affordable and robust thermionic converters have the potential to displace century old mechanical engines and turbines as a primary means of electrical power generation in the near future. High efficiency converters that operate at a small scale could be used to generate power locally and alleviate the need for large scale power transmission systems. Electron and negative cesium ion back emission from the anode are considered, as well as device longevity and fabrication feasibility.

Characterization of transimpedance amplifier as optical to electrical converter on designing optical instrumentation

NASA Astrophysics Data System (ADS)

Hanto, D.; Ula, R. K.

2017-05-01

Optical to electrical converter is the main components for designing of the optical instrumentations. In addition, this component is also used as signal conditioning. This component usually consists of a photo detector and amplifier. In this paper, characteristics of commercial amplifiers from Thorlabs PDA50B-EC has been observed. The experiment was conducted by diode laser with power of -5 dBm and wavelength 1310 nm; the optical attenuator to vary optical power from 0 to 60 dB, optical to electrical converter from Thorlabs Amplifier PDA50B-EC; multimode optical fiber to guide the laser; and digital voltmeter to measure the output of converter. The results of the characterization indicate that each channel amplification has a non-linear correlation between optical and electrical parameter; optical conversion measurement range of 20-23 dB to full scale; and different measurement coverage area. If this converter will be used as a part component of optical instrumentation so it should be adjusted suitably with the optical power source. Then, because of the correlation equation is not linear so calculation to determine the interpretation also should be considered in addition to the transfer function of the optical sensor.

Space solar power - An energy alternative

NASA Technical Reports Server (NTRS)

Johnson, R. W.

1978-01-01

The space solar power concept is concerned with the use of a Space Power Satellite (SPS) which orbits the earth at geostationary altitude. Two large symmetrical solar collectors convert solar energy directly to electricity using photovoltaic cells woven into blankets. The dc electricity is directed to microwave generators incorporated in a transmitting antenna located between the solar collectors. The antenna directs the microwave beam to a receiving antenna on earth where the microwave energy is efficiently converted back to dc electricity. The SPS design promises 30-year and beyond lifetimes. The SPS is relatively pollution free as it promises earth-equivalence of 80-85% efficient ground-based thermal power plant.

Method and apparatus for controlling a microturbine

DOEpatents

Garces, Luis Jose; Cardinal, Mark Edward; Sinha, Gautam; Dame, Mark Edward

2005-08-02

An apparatus for controlling a microturbine, the apparatus including: a rectifier adapted for converting at least one generated voltage from the microturbine to a DC link voltage; an inverter adapted for converting the DC link voltage to at least one inverter output voltage, the at least one inverter output voltage being electrically coupled to an external power bus; a starter drive adapted for converting at least one starter input voltage to at least one starter output voltage, the at least one starter input voltage being electrically coupled to the external power bus, the at least one starter output voltage being electrically coupled to the microturbine.

Radiatively coupled thermionic and thermoelectric power system concept

NASA Technical Reports Server (NTRS)

Shimada, K.; Ewell, R.

1981-01-01

The study presented showed that the large power systems (about 100 kW) utilizing radiatively coupled thermionic or thermoelectric converters could be designed so that the power subsystem could be contained in a Space Shuttle bay as a part of an electrically propelled spacecraft. The radiatively coupled system requires a large number of individual converters since the transferred heat is smaller than with the conductively coupled system, but the advantages of the new system indicates merit for further study. The advantages are (1) good electrical isolation between converters and the heat source, (2) physical separation of converters from the heat source (making the system fabrication manageable), and (3) elimination of radiator heat pipes, which are required in an all-heat-pipe power system. In addition, the specific weight of the radiatively coupled power systems favorably compares with that of the all-heat-pipe systems.

Controller for a wave energy converter

DOEpatents

Wilson, David G.; Bull, Diana L.; Robinett, III, Rush D.

2015-09-22

A wave energy converter (WEC) is described, the WEC including a power take off (PTO) that converts relative motion of bodies of the WEC into electrical energy. A controller controls operation of the PTO, causing the PTO to act as a motor to widen a wave frequency spectrum that is usable to generate electrical energy.

Activity and accomplishments of dish/Stirling electric power system development

NASA Technical Reports Server (NTRS)

Livingston, F. R.

1985-01-01

The development of the solar parabolic-dish/Stirling-engine electricity generating plant known as the dish/Stirling electric power system is described. The dish/Stirling electric power system converts sunlight to electricity more efficiently than any known existing solar electric power system. The fabrication and characterization of the test bed concentrators that were used for Stirling module testing and of the development of parabolic dish concentrator No. 2, an advanced solar concentrator unit considered for use with the Stirling power conversion unit is discussed.

Enhanced distributed energy resource system

DOEpatents

Atcitty, Stanley [Albuquerque, NM; Clark, Nancy H [Corrales, NM; Boyes, John D [Albuquerque, NM; Ranade, Satishkumar J [Las Cruces, NM

2007-07-03

A power transmission system including a direct current power source electrically connected to a conversion device for converting direct current into alternating current, a conversion device connected to a power distribution system through a junction, an energy storage device capable of producing direct current connected to a converter, where the converter, such as an insulated gate bipolar transistor, converts direct current from an energy storage device into alternating current and supplies the current to the junction and subsequently to the power distribution system. A microprocessor controller, connected to a sampling and feedback module and the converter, determines when the current load is higher than a set threshold value, requiring triggering of the converter to supply supplemental current to the power transmission system.

Conversion of NO to NO(2) in air by a micro electric NO(x) converter based on a corona discharge process.

PubMed

Yoon, Seung-Il; Heo, Sungmoo; Song, Soonho; Kim, Yong-Jun

2010-06-01

A micro-electric-NO(x)-converter based on volume treatment is proposed for the evaluation of NO(x) concentrations in air. It can electrically convert NO(x) mixture from variable mixing rates into a fixed-mixing rate of 25% NO(2) and 75% NO using the corona discharge process with stable conversion efficiency and high throughput (space velocity = 6.3 x 10(4) h(-1)). The micro-electric-NO(x)-converter is based on a volume process. Applying high voltage to the electrodes of the micro-electric-NO(x)-converter generates a corona discharge. This discharge creates high-energy electrons, which collide with gas molecules. After these collisions, NO and O(2) are broken into single atoms, and they are re-combined as a balanced form, NO(2) in this case. The fabricated micro-electric-NO(x)-converter converted NO into NO(2) at conversion efficiency of 25.63%, when 5.5 kV (the applied corona power = 0.196 W) was applied to the micro-electric-NO(x)-converter.

Compact Hybrid Automotive Propulsion System

NASA Technical Reports Server (NTRS)

Lupo, G.

1986-01-01

Power train proposed for experimental vehicle powered by internal combustion engine and electric motor. Intended for front-wheel drive automobile, power train mass produced using existing technology. System includes internal-combustion engine, electric motor, continuously variable transmission, torque converter, differential, and control and adjustment systems for electric motor and transmission. Continuously variable transmission integrated into hydraulic system that also handles power steering and power brakes. Batteries for electric motor mounted elsewhere in vehicle.

Methode unifiee de simulation et de conception des convertisseurs de puissance

NASA Astrophysics Data System (ADS)

Fortin Blanchette, Handy

High frequency power converters are now master piece in emerging new renewable energy applications such as hybrid vehicules. These new technologies merge the power of electrical machine with the thermal motor power. The power converters used to control those electrical machines are embeded technologies with high efficiency conversion and a high reliability. More than ground vehicule applications, embeded power converters are now present in aeronautic and aerospace domains. In this sense, high reliability and high efficiency are now important characteristics that are not only suitable but needed. In spite of this progression, power converters development remains today a complex science. Even if advanced complex techniques are now available to increase the converter stability, there are no systemic rules to design the converter physical assembly. Very often, an artistic approach is used to place the components inside the converter in the more convenient places. This lack of rigor about EMI problems is not so surprising because this kind of analysis is costly and risky. In general, to solve this type of problems, one designs a second and a third printed circuit generation which is not necessarily a quick and systematic approach. To overcome these difficulties, the main goal of this thesis is to provide simple and improved tools for power converter circuit designers. The key point are to solve EMI and reliability problems at the earlier design stage and not during the prototyping phase. Many solutions are exposed in this text about the magnetic field orientation, leakage inductances identification, power semiconductors modeling and electromagnetic modeling of power converters. The exactness of these methods is proved by using it to develop a matrix converter. The printed circuits are designed to orient properly the magnetic field enabling to introduce low power sensing circuits directly inside the converter. This application is one of the numerous possibilities offered by the techniques presented in this document. Keywords: power converters, modeling, electromagnetic interferences.

Photonic-powered cable assembly

DOEpatents

Sanderson, Stephen N.; Appel, Titus James; Wrye, IV, Walter C.

2013-01-22

A photonic-cable assembly includes a power source cable connector ("PSCC") coupled to a power receive cable connector ("PRCC") via a fiber cable. The PSCC electrically connects to a first electronic device and houses a photonic power source and an optical data transmitter. The fiber cable includes an optical transmit data path coupled to the optical data transmitter, an optical power path coupled to the photonic power source, and an optical feedback path coupled to provide feedback control to the photonic power source. The PRCC electrically connects to a second electronic device and houses an optical data receiver coupled to the optical transmit data path, a feedback controller coupled to the optical feedback path to control the photonic power source, and a photonic power converter coupled to the optical power path to convert photonic energy received over the optical power path to electrical energy to power components of the PRCC.

Photonic-powered cable assembly

DOEpatents

Sanderson, Stephen N; Appel, Titus James; Wrye, IV, Walter C

2014-06-24

A photonic-cable assembly includes a power source cable connector ("PSCC") coupled to a power receive cable connector ("PRCC") via a fiber cable. The PSCC electrically connects to a first electronic device and houses a photonic power source and an optical data transmitter. The fiber cable includes an optical transmit data path coupled to the optical data transmitter, an optical power path coupled to the photonic power source, and an optical feedback path coupled to provide feedback control to the photonic power source. The PRCC electrically connects to a second electronic device and houses an optical data receiver coupled to the optical transmit data path, a feedback controller coupled to the optical feedback path to control the photonic power source, and a photonic power converter coupled to the optical power path to convert photonic energy received over the optical power path to electrical energy to power components of the PRCC.

75 FR 44289 - MET Laboratories, Inc.; Application for Expansion of Recognition

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-28

... State Controls for Appliances UL 412 Refrigeration Unit Coolers UL 458* Power Converters/Inverters and Power Converter/Inverter Systems for Land Vehicles and Marine Crafts UL 466 Electric Scales UL 561 Floor...

Development of a biomechanical energy harvester.

PubMed

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

2009-06-23

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. 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. 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. 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.

Development of a biomechanical energy harvester

PubMed Central

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

2009-01-01

Background Biomechanical energy harvesting–generating electricity from people during daily activities–is a promising alternative to batteries for powering increasingly sophisticated portable devices. We recently developed a wearable knee-mounted energy harvesting device that generated electricity during human walking. In this methods-focused paper, we explain the physiological principles that guided our design process and present a detailed description of our device design with an emphasis on new analyses. Methods Effectively harvesting energy from walking requires a small lightweight device that efficiently converts intermittent, bi-directional, low speed and high torque mechanical power to electricity, and selectively engages power generation to assist muscles in performing negative mechanical work. To achieve this, our device used a one-way clutch to transmit only knee extension motions, a spur gear transmission to amplify the angular speed, a brushless DC rotary magnetic generator to convert the mechanical power into electrical power, a control system to determine when to open and close the power generation circuit based on measurements of knee angle, and a customized orthopaedic knee brace to distribute the device reaction torque over a large leg surface area. Results The device selectively engaged power generation towards the end of swing extension, assisting knee flexor muscles by producing substantial flexion torque (6.4 Nm), and efficiently converted the input mechanical power into electricity (54.6%). Consequently, six subjects walking at 1.5 m/s generated 4.8 ± 0.8 W of electrical power with only a 5.0 ± 21 W increase in metabolic cost. Conclusion Biomechanical energy harvesting is capable of generating substantial amounts of electrical power from walking with little additional user effort making future versions of this technology particularly promising for charging portable medical devices. PMID:19549313

The Alkali Metal Thermal-To-Electric Converter for Solar System Exploration

NASA Technical Reports Server (NTRS)

Ryan, M.

1999-01-01

AMTEC, the Alkali Metal Thermal to Electric Converter, is a direct thermal to electric energy conversion device; it has been demostrated to perform at high power densities, with open circuit voltages in single electrochemical cells up to 1.6 V and current desities up to 2.0 A/cm(sup 2).

How to Transform Mechanical Work into Electrical Energy Using a Capacitor

ERIC Educational Resources Information Center

Skumiel, A.

2011-01-01

In this paper the method of converting mechanical work into electrical energy with the participation of a preliminarily charged condenser while the electrodes are sliding in it is presented. Using this method, we can obtain a considerable increase of converted electrical power, depending on the initial energy of the charged condenser, distance…

Microfabricated rankine cycle steam turbine for power generation and methods of making the same

NASA Technical Reports Server (NTRS)

Muller, Norbert (Inventor); Lee, Changgu (Inventor); Frechette, Luc (Inventor)

2009-01-01

In accordance with the present invention, an integrated micro steam turbine power plant on-a-chip has been provided. The integrated micro steam turbine power plant on-a-chip of the present invention comprises a miniature electric power generation system fabricated using silicon microfabrication technology and lithographic patterning. The present invention converts heat to electricity by implementing a thermodynamic power cycle on a chip. The steam turbine power plant on-a-chip generally comprises a turbine, a pump, an electric generator, an evaporator, and a condenser. The turbine is formed by a rotatable, disk-shaped rotor having a plurality of rotor blades disposed thereon and a plurality of stator blades. The plurality of stator blades are interdigitated with the plurality of rotor blades to form the turbine. The generator is driven by the turbine and converts mechanical energy into electrical energy.

EMTP based stability analysis of space station electric power system in a test bed environment

NASA Technical Reports Server (NTRS)

Dravid, Narayan V.; Kacpura, Thomas J.; Oconnor, Andrew M.

1992-01-01

The Space Station Freedom Electric Power System (EPS) will convert solar energy into electric energy and distribute the same using an 'all dc', Power Management and Distribution (PMAD) System. Power conditioning devices (dc to dc converters) are needed to interconnect parts of this system operating at different nominal voltage levels. Operation of such devices could generate under damped oscillations (instability) under certain conditions. Criteria for instability are examined and verified for a single device. Suggested extension of the criteria to a system operation is examined by using the EMTP model of the PMAD DC test bed. Wherever possible, data from the test bed is compared with the modeling results.

EMTP based stability analysis of Space Station Electric Power System in a test bed environment

NASA Technical Reports Server (NTRS)

Dravid, Narayan V.; Kacpura, Thomas J.; O'Connor, Andrew M.

1992-01-01

The Space Station Freedom Electric Power System (EPS) will convert solar energy into electric energy and distribute the same using an 'all dc', Power Management and Distribution (PMAD) System. Power conditioning devices (dc to dc converters) are needed to interconnect parts of this system operating at different nominal voltage levels. Operation of such devices could generate under damped oscillations (instability) under certain conditions. Criteria for instability are examined and verified for a single device. Suggested extension of the criteria to a system operation is examined by using the EMTP model of the PMAD dc test bed. Wherever possible, data from the test bed is compared with the modeling results.

Electromagnetic wave energy converter

NASA Technical Reports Server (NTRS)

Bailey, R. L. (Inventor)

1973-01-01

Electromagnetic wave energy is converted into electric power with an array of mutually insulated electromagnetic wave absorber elements each responsive to an electric field component of the wave as it impinges thereon. Each element includes a portion tapered in the direction of wave propagation to provide a relatively wideband response spectrum. Each element includes an output for deriving a voltage replica of the electric field variations intercepted by it. Adjacent elements are positioned relative to each other so that an electric field subsists between adjacent elements in response to the impinging wave. The electric field results in a voltage difference between adjacent elements that is fed to a rectifier to derive dc output power.

System Design for a Nuclear Electric Spacecraft Utilizing Out-of-core Thermionic Conversion

NASA Technical Reports Server (NTRS)

Estabrook, W. C.; Phillips, W. M.; Hsieh, T.

1976-01-01

Basic guidelines are presented for a nuclear space power system which utilizes heat pipes to transport thermal power from a fast nuclear reactor to an out of core thermionic converter array. Design parameters are discussed for the nuclear reactor, heat pipes, thermionic converters, shields (neutron and gamma), waste heat rejection systems, and the electrical bus bar-cable system required to transport the high current/low voltage power to the processing equipment. Dimensions are compatible with shuttle payload bay constraints.

Evolution of Automotive Chopper Circuits Towards Ultra High Efficiency and Power Density

NASA Astrophysics Data System (ADS)

Pavlovsky, Martin; Tsuruta, Yukinori; Kawamura, Atsuo

Automotive industry is considered to be one of the main contributors to environmental pollution and global warming. Therefore, many car manufacturers are in near future planning to introduce hybrid electric vehicles (HEV), fuel cell electric vehicles (FCEV) and pure electric vehicles (EV) to make our cars more environmentally friendly. These new vehicles require highly efficient and small power converters. In recent years, considerable improvements were made in designing such converters. In this paper, an approach based on so called Snubber Assisted Zero Voltage and Zero Current Switching topology otherwise also known as SAZZ is presented. This topology has evolved to be one of the leaders in the field of highly efficient converters with high power densities. Evolution and main features of this topology are briefly discussed. Capabilities of the topology are demonstrated on two case study prototypes based on different design approaches. The prototypes are designed to be fully bi-directional for peak power output of 30kW. Both designs reached efficiencies close to 99% in wide load range. Power densities over 40kW/litre are attainable in the same time. Combination of MOSFET technology and SAZZ topology is shown to be very beneficial to converters designed for EV applications.

Next Generation Inverter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Zilai; Gough, Charles

The goal of this Cooperative Agreement was the development of a Next Generation Inverter for General Motors’ electrified vehicles, including battery electric vehicles, range extended electric vehicles, plug-in hybrid electric vehicles and hybrid electric vehicles. The inverter is a critical electronics component that converts battery power (DC) to and from the electric power for the motor (AC).

A preliminary design for a satellite power system

NASA Technical Reports Server (NTRS)

Enriquez, Clara V.; Kokaly, Ray; Nandi, Saumya; Timmons, Mike; Garrard, Mark; Mercado, Rommel; Rogers, Brian; Ugaz, Victor

1991-01-01

Outlined here is a preliminary design for a Solar Power Satellite (SPS) system. The SPS will provide a clean, reliable source of energy for mass consumption. The system will use satellites in geostationary orbits around the Earth to capture the sun's energy. The intercepted sunlight will be converted to laser beam energy which can be transmitted to the Earth's surface. Ground systems on the Earth will convert the transmissions from space into electric power. The preliminary design for the SPS consists of one satellite in orbit around the Earth transmitting to one ground station. The SPs technology uses multi-layer solar cell technology arranged on a 20 sq km planar array to intercept sunlight and convert it to an electric voltage. Power conditioning devices then send the electricity to a laser, which transmits the power to the surface of the Earth. A ground station will convert the beam into electricity. Construction will take place in low Earth orbit and array sections, 20 in total, will be sailed on the solar wind out to the GEO location in 150 days. These individual transportation sections are referred to as solar sailing panels (SSAPs). The primary truss elements used to support the arrays are composed on composite tubular members in a pentahedral arrangement. Smart segments consisting of passive and active damping devices will increase the control of dynamic SPS modes.

Converter topologies for common mode voltage reduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodriguez, Fernando

An inverter includes a three-winding transformer, a DC-AC inverter electrically coupled to the first winding of the transformer, a cycloconverter electrically coupled to the second winding of the transformer, and an active filter electrically coupled to the third winding of the transformer. The DC-AC inverter is adapted to convert the input DC waveform to an AC waveform delivered to the transformer at the first winding. The cycloconverter is adapted to convert an AC waveform received at the second winding of the transformer to the output AC waveform having a grid frequency of the AC grid. The active filter is adaptedmore » to sink and source power with one or more energy storage devices based on a mismatch in power between the DC source and the AC grid. At least two of the DC-AC inverter, the cycloconverter, or the active filter are electrically coupled via a common reference electrical interconnect.« less

Developments in Turbo-Brayton Power Converters

NASA Astrophysics Data System (ADS)

Zagarola, Mark V.; Crowley, Christopher J.; Swift, Walter L.

2003-01-01

Design studies show that a Brayton cycle power unit is an extremely attractive option for thermal-to-electric power conversion on long-duration, space missions. At low power levels (50 to 100 We), a Brayton system should achieve a conversion efficiency between 20% and 40% depending on the radiative heat sink temperature. The expected mass of the converter for these power levels is about 3 kg. The mass of the complete system consisting of the converter, the electronics, a radiator, and a single general purpose heat source should be about 6 kg. The system is modular and the technology is readily scalable to higher power levels (to greater than 10 kWe) where conversion efficiencies of between 28% and 45% are expected, the exact value depending on sink temperature and power level. During a recently completed project, key physical features of the converter were determined, and key operating characteristics were demonstrated for a system of this size. The key technologies in these converters are derived from those which have been developed and successfully implemented in miniature turbo-Brayton cryogenic refrigerators for space applications. These refrigerators and their components have been demonstrated to meet rigorous requirements for vibration emittance and susceptibility, acoustic susceptibility, electromagnetic interference and susceptibility, environmental cycling, and endurance. Our progress in extending the underlying turbo-Brayton cryocooler technologies to thermal-to-electric power converters is the subject of this paper.

Mini Solar and Sea Current Power Generation System

NASA Astrophysics Data System (ADS)

Almenhali, Abdulrahman; Alshamsi, Hatem; Aljunaibi, Yaser; Almussabi, Dheyab; Alshehhi, Ahmed; Hilal, Hassan Bu

2017-07-01

The power demand in United Arab Emirates is increased so that there is a consistent power cut in our region. This is because of high power consumption by factories and also due to less availability of conventional energy resources. Electricity is most needed facility for the human being. All the conventional energy resources are depleting day by day. So we have to shift from conventional to non-conventional energy resources. In this the combination of two energy resources is takes place i.e. wind and solar energy. This process reviles the sustainable energy resources without damaging the nature. We can give uninterrupted power by using hybrid energy system. Basically this system involves the integration of two energy system that will give continuous power. Solar panels are used for converting solar energy and wind turbines are used for converting wind energy into electricity. This electrical power can utilize for various purpose. Generation of electricity will be takes place at affordable cost. This paper deals with the generation of electricity by using two sources combine which leads to generate electricity with affordable cost without damaging the nature balance. The purpose of this project was to design a portable and low cost power system that combines both sea current electric turbine and solar electric technologies. This system will be designed in efforts to develop a power solution for remote locations or use it as another source of green power.

Investigations of DC power supplies with optoelectronic transducers and RF energy converters

NASA Astrophysics Data System (ADS)

Guzowski, B.; Gozdur, R.; Bernacki, L.; Lakomski, M.

2016-04-01

Fiber Distribution Cabinets (FDC) monitoring systems are increasingly popular. However it is difficult to realize such system in passive FDC, due to lack of source of power supply. In this paper investigation of four different DC power supplies with optoelectronic transducers is described. Two converters: photovoltaic power converter and PIN photodiode can convert the light transmitted through the optical fiber to electric energy. Solar cell and antenna RF-PCB are also tested. Results presented in this paper clearly demonstrate that it is possible to build monitoring system in passive FDC. During the tests maximum obtained output power was 11 mW. However all converters provided enough power to excite 32-bit microcontroller with ARM-cores and digital thermometer.

Modelling, Simulation and Construction of a DC/DC Boost Power Converter: A School Experimental System

ERIC Educational Resources Information Center

Silva-Ortigoza, R.; Silva-Ortigoza, G.; Hernandez-Guzman, V. M.; Saldana-Gonzalez, G.; Marcelino-Aranda, M.; Marciano-Melchor, M.

2012-01-01

We introduce a dc/dc boost power converter as a didactic prototype intended to support courses on electric circuit analysis experimentally. The corresponding mathematical model is obtained, the converter is designed and an experimental setup is described, constructed and tested. Simplicity of construction as well as low cost of components renders…

The TELEC - A plasma type of direct energy converter. [Thermo-Electronic Laser Energy Converter for electric power generation

NASA Technical Reports Server (NTRS)

Britt, E. J.

1978-01-01

The Thermo-Electronic Laser Energy Converter (TELEC) is a high-power density plasma device designed to convert a 10.6-micron CO2 laser beam into electric power. Electromagnetic radiation is absorbed in plasma electrons, creating a high-electron temperature. Energetic electrons diffuse from the plasma and strike two electrodes having different areas. The larger electrode collects more electrons and there is a net transport of current. An electromagnetic field is generated in the external circuit. A computer program has been designed to analyze TELEC performance allowing parametric variation for optimization. Values are presented for TELEC performance as a function of cesium pressure and for current density and efficiency as a function of output voltage. Efficiency is shown to increase with pressure, reaching a maximum over 45%.

Observer-based higher order sliding mode control of power factor in three-phase AC/DC converter for hybrid electric vehicle applications

NASA Astrophysics Data System (ADS)

Liu, Jianxing; Laghrouche, Salah; Wack, Maxime

2014-06-01

In this paper, a full-bridge boost power converter topology is studied for power factor control, using output higher order sliding mode control. The AC/DC converters are used for charging the battery and super-capacitor in hybrid electric vehicles from the utility. The proposed control forces the input currents to track the desired values, which can control the output voltage while keeping the power factor close to one. Super-twisting sliding mode observer is employed to estimate the input currents and load resistance only from the measurement of output voltage. Lyapunov analysis shows the asymptotic convergence of the closed-loop system to zero. Multi-rate simulation illustrates the effectiveness and robustness of the proposed controller in the presence of measurement noise.

Power Management and Distribution System Developed for Thermionic Power Converters

NASA Technical Reports Server (NTRS)

Baez, Anastacio N.

1998-01-01

A spacecraft solar, bimodal system combines propulsion and power generation into a single integrated system. An Integrated Solar Upper Stage (ISUS) provides orbital transfer capabilities, power generation for payloads, and onboard propulsion to the spacecraft. A key benefit of a bimodal system is a greater payload-to-spacecraft mass ratio resulting in lower launch vehicle requirements. Scaling down to smaller launch vehicles increases space access by reducing overall mission cost. NASA has joined efforts with the Air Force Phillips Laboratory to develop enabling technologies for such a system. The NASA/Air Force bimodal concept uses solar concentrators to focus energy into an integrated power plant. This power plant consists of a graphite core that stores thermal energy within a cavity. An array of thermionic converters encircles the graphite cavity and provides electrical energy conversion functions. During the power generation phase of the bimodal system, the thermionic converters are exposed to the heated cavity and convert the thermal energy to electricity. Near-term efforts of the ISUS bimodal program are focused on a ground demonstration of key technologies in order to proceed to a full space flight test. Thermionic power generation is one key technology of the bimodal concept. Thermionic power converters impose unique operating requirements upon a power management and distribution (PMAD) system design. Single thermionic converters supply large currents at very low voltages. Operating voltages can vary over a range of up to 3 to 1 as a function of operating temperature. Most spacecraft loads require regulated 28-volts direct-current (Vdc) power. A combination of series-connected converters and powerprocessing boosters is required to deliver power to the spacecraft's payloads at this level.

Bi-directional power control system for voltage converter

DOEpatents

Garrigan, Neil Richard; King, Robert Dean; Schwartz, James Edward

1999-01-01

A control system for a voltage converter includes: a power comparator for comparing a power signal on input terminals of the converter with a commanded power signal and producing a power comparison signal; a power regulator for transforming the power comparison signal to a commanded current signal; a current comparator for comparing the commanded current signal with a measured current signal on output terminals of the converter and producing a current comparison signal; a current regulator for transforming the current comparison signal to a pulse width modulator (PWM) duty cycle command signal; and a PWM for using the PWM duty cycle command signal to control electrical switches of the converter. The control system may further include: a command multiplier for converting a voltage signal across the output terminals of the converter to a gain signal having a value between zero (0) and unity (1), and a power multiplier for multiplying the commanded power signal by the gain signal to provide a limited commanded power signal, wherein power comparator compares the limited commanded power signal with the power signal on the input terminals.

Bi-directional power control system for voltage converter

DOEpatents

Garrigan, N.R.; King, R.D.; Schwartz, J.E.

1999-05-11

A control system for a voltage converter includes: a power comparator for comparing a power signal on input terminals of the converter with a commanded power signal and producing a power comparison signal; a power regulator for transforming the power comparison signal to a commanded current signal; a current comparator for comparing the commanded current signal with a measured current signal on output terminals of the converter and producing a current comparison signal; a current regulator for transforming the current comparison signal to a pulse width modulator (PWM) duty cycle command signal; and a PWM for using the PWM duty cycle command signal to control electrical switches of the converter. The control system may further include: a command multiplier for converting a voltage signal across the output terminals of the converter to a gain signal having a value between zero (0) and unity (1), and a power multiplier for multiplying the commanded power signal by the gain signal to provide a limited commanded power signal, wherein power comparator compares the limited commanded power signal with the power signal on the input terminals. 10 figs.

About the feasibilities of controlling the properties of thermoelectric energy converters using optical radiation

NASA Astrophysics Data System (ADS)

Kshevetsky, Oleg S.

2018-01-01

We represent evaluating analysis of the feasibilities for controlling the properties of thermoelectric energy converters using EM radiation in the regimes of cooling, heating, electromotive force generation, or electric current generation. Thus we investigate the influence of optical radiation both on electric conductivity and thermo-electromotive force coefficient of thermoelectric materials. We also discuss promising applications for controlling the properties of thermoelectric energy converters using EM radiation. We represent the results of experimental study of positionsensitive energy converters in the regimes of electromotive force generation and the electric current generation (in part, photo-thermoelectric position-sensitive temperature detectors), position-sensitive photo-thermoelectric energy converters in the regimes of cooling, heating, parallel photoelectric and thermoelectric conversion of sun-light optical radiation into electric power.

Potential converter for laser-power beaming

NASA Technical Reports Server (NTRS)

Walker, Gilbert H.; Williams, Michael D.; Schuster, Gregory L.; Iles, Peter A.

1991-01-01

Future space missions, such as those associated with the Space Exploration Initiative (SEI), will require large amounts of power for operation of bases, rovers, and orbit transfer vehicles. One method for supplying this power is to beam power from a spaced based or Earth based laser power station to a receiver where laser photons can be converted to electricity. Previous research has described such laser power stations orbiting the Moon and beaming power to a receiver on the surface of the Moon by using arrays of diode lasers. Photovoltaic converters that can be efficiently used with these diode lasers are described.

Integration of regenerative shock absorber into vehicle electric system

NASA Astrophysics Data System (ADS)

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

2014-03-01

Regenerative/Energy harvesting shock absorbers have a great potential to increase fuel efficiency and provide suspension damping simultaneously. In recent years there's intensive work on this topic, but most researches focus on electricity extraction from vibration and harvesting efficiency improvement. The integration of electricity generated from regenerative shock absorbers into vehicle electric system, which is very important to realize the fuel efficiency benefit, has not been investigated. This paper is to study and demonstrate the integration of regenerative shock absorber with vehicle alternator, battery and in-vehicle electrical load together. In the presented system, the shock absorber is excited by a shaker and it converts kinetic energy into electricity. The harvested electricity flows into a DC/DC converter which realizes two functions: controlling the shock absorber's damping and regulating the output voltage. The damping is tuned by controlling shock absorber's output current, which is also the input current of DC/DC converter. By adjusting the duty cycles of switches in the converter, its input impedance together with input current can be adjusted according to dynamic damping requirements. An automotive lead-acid battery is charged by the DC/DC converter's output. To simulate the working condition of combustion engine, an AC motor is used to drive a truck alternator, which also charges the battery. Power resistors are used as battery's electrical load to simulate in-vehicle electrical devices. Experimental results show that the proposed integration strategy can effectively utilize the harvested electricity and power consumption of the AC motor is decreased accordingly. This proves the combustion engine's load reduction and fuel efficiency improvement.

Electrified Automotive Powertrain Architecture Using Composite DC–DC Converters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Hua; Kim, Hyeokjin; Erickson, Robert

In a hybrid or electric vehicle powertrain, a boost dc-dc converter enables reduction of the size of the electric machine and optimization of the battery system. Design of the powertrain boost converter is challenging because the converter must be rated at high peak power, while efficiency at medium-to-light load is critical for the vehicle system performance. By addressing only some of the loss mechanisms, previously proposed efficiency improvement approaches offer limited improvements in size, cost, and efficiency tradeoffs. This article shows how all dominant loss mechanisms in automotive powertrain applications can be mitigated using a new boost composite converter approach.more » In the composite dc-dc architecture, the loss mechanisms associated with indirect power conversion are addressed explicitly, resulting in fundamental efficiency improvements over wide ranges of operating conditions. Several composite converter topologies are presented and compared to state-of-the-art boost converter technologies. It is found that the selected boost composite converter results in a decrease in the total loss by a factor of 2-4 for typical drive cycles. Furthermore, the total system capacitor power rating and energy rating are substantially reduced, which implies potentials for significant reductions in system size and cost.« less

Electrified Automotive Powertrain Architecture Using Composite DC–DC Converters

DOE PAGES

Chen, Hua; Kim, Hyeokjin; Erickson, Robert; ...

2017-01-01

In a hybrid or electric vehicle powertrain, a boost dc-dc converter enables reduction of the size of the electric machine and optimization of the battery system. Design of the powertrain boost converter is challenging because the converter must be rated at high peak power, while efficiency at medium-to-light load is critical for the vehicle system performance. By addressing only some of the loss mechanisms, previously proposed efficiency improvement approaches offer limited improvements in size, cost, and efficiency tradeoffs. This article shows how all dominant loss mechanisms in automotive powertrain applications can be mitigated using a new boost composite converter approach.more » In the composite dc-dc architecture, the loss mechanisms associated with indirect power conversion are addressed explicitly, resulting in fundamental efficiency improvements over wide ranges of operating conditions. Several composite converter topologies are presented and compared to state-of-the-art boost converter technologies. It is found that the selected boost composite converter results in a decrease in the total loss by a factor of 2-4 for typical drive cycles. Furthermore, the total system capacitor power rating and energy rating are substantially reduced, which implies potentials for significant reductions in system size and cost.« less

An Integrated Onboard Charger and Accessary Power Converter for Plug-in Electric Vehicles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Su, Gui-Jia; Tang, Lixin

2013-01-01

Abstract: In this paper, an integrated onboard battery charger and accessary dc-dc converter for plug-in electric vehicles (PEVs) is presented. The idea is to utilize the already available traction drive inverters and motors of a PEV as the frond converter of the charger circuit and the transformer of the 14 V accessary dc-dc converter to provide galvanic isolation. The topology was verified by modeling and experimental results on a 5 kW charger prototype

Performance tests of a power-electronics converter for multi-megawatt wind turbines using a grid emulator

NASA Astrophysics Data System (ADS)

Rizqy Averous, Nurhan; Berthold, Anica; Schneider, Alexander; Schwimmbeck, Franz; Monti, Antonello; De Doncker, Rik W.

2016-09-01

A vast increase of wind turbines (WT) contribution in the modern electrical grids have led to the development of grid connection requirements. In contrast to the conventional test method, testing power-electronics converters for WT using a grid emulator at Center for Wind Power Drives (CWD) RWTH Aachen University offers more flexibility for conducting test scenarios. Further analysis on the performance of the device under test (DUT) is however required when testing with grid emulator since the characteristic of the grid emulator might influence the performance of the DUT. This paper focuses on the performance analysis of the DUT when tested using grid emulator. Beside the issue regarding the current harmonics, the performance during Fault Ride-Through (FRT) is discussed in detail. A power hardware in the loop setup is an attractive solution to conduct a comprehensive study on the interaction between the power-electronics converters and the electrical grids.

Learning Platform for Study of Power Electronic Application in Power Systems

ERIC Educational Resources Information Center

Bauer, P.; Rompelman, O.

2005-01-01

Present engineering has to deal with increasingly complex systems. In particular, this is the case in electrical engineering. Though this is obvious in microelectronics, also in the field of power systems engineers have to design, operate and maintain highly complex systems such as power grids, energy converters and electrical drives. This is…

Wireless power charging using point of load controlled high frequency power converters

DOEpatents

Miller, John M.; Campbell, Steven L.; Chambon, Paul H.; Seiber, Larry E.; White, Clifford P.

2015-10-13

An apparatus for wirelessly charging a battery of an electric vehicle is provided with a point of load control. The apparatus includes a base unit for generating a direct current (DC) voltage. The base unit is regulated by a power level controller. One or more point of load converters can be connected to the base unit by a conductor, with each point of load converter comprising a control signal generator that transmits a signal to the power level controller. The output power level of the DC voltage provided by the base unit is controlled by power level controller such that the power level is sufficient to power all active load converters when commanded to do so by any of the active controllers, without generating excessive power that may be otherwise wasted.

Converter topologies and control

DOEpatents

Rodriguez, Fernando; Qin, Hengsi; Chapman, Patrick

2018-05-01

An inverter includes a transformer that includes a first winding, a second winding, and a third winding, a DC-AC inverter electrically coupled to the first winding of the transformer, a cycloconverter electrically coupled to the second winding of the transformer, an active filter electrically coupled to the third winding of the transformer. The DC-AC inverter is adapted to convert the input DC waveform to an AC waveform delivered to the transformer at the first winding. The cycloconverter is adapted to convert an AC waveform received at the second winding of the transformer to the output AC waveform having a grid frequency of the AC grid. The active filter is adapted to sink and source power with one or more energy storage devices based on a mismatch in power between the DC source and the AC grid.

Proposed electromagnetic wave energy converter

NASA Technical Reports Server (NTRS)

Bailey, R. L.

1973-01-01

Device converts wave energy into electric power through array of insulated absorber elements responsive to field of impinging electromagnetic radiation. Device could also serve as solar energy converter that is potentially less expensive and fragile than solar cells, yet substantially more efficient.

Solar fed DC-DC single ended primary inductance converter for low power applications

NASA Astrophysics Data System (ADS)

Narendranath, K. V.; Viswanath, Y.; Babu, K. Suresh; Arunkumar, G.; Elangovan, D.

2017-11-01

This paper presents 34 to 36 volts. SEPIC converter for solar fed applications. Now days, there has been tremendous increase in the usage of solar energy and this solar energy is most valuable energy source available all around the world. The solar energy system require a Dc-Dc converter in order to modulate and govern the changing output of the panel. In this paper, a system comprising of Single Ended Primary Inductance Converter [SEPIC] integrated with solar panel is proposed. This paper proposes SEPIC power converter design that will secure high performance and cost efficiency while powering up a LAMP load. This power converter designed with low output ripple voltage, higher efficiency and less electrical pressure on the power switching elements. The simulation and prototype hardware results are presented in this paper.

Closed Brayton Cycle Power Conversion Unit for Fission Surface Power Phase I Final Report

NASA Technical Reports Server (NTRS)

Fuller, Robert L.

2010-01-01

A Closed Brayton cycle power conversion system has been developed to support the NASA fission surface power program. The goal is to provide electricity from a small nuclear reactor heat source for surface power production for lunar and Mars environments. The selected media for a heat source is NaK 78 with water as a cooling source. The closed Brayton cycle power was selected to be 12 kWe output from the generator terminals. A heat source NaK temperature of 850 K plus or minus 25 K was selected. The cold source water was selected at 375 K plus or minus 25 K. A vacuum radiation environment of 200 K is specified for environmental operation. The major components of the system are the power converter, the power controller, and the top level data acquisition and control unit. The power converter with associated sensors resides in the vacuum radiation environment. The power controller and data acquisition system reside in an ambient laboratory environment. Signals and power are supplied across the pressure boundary electrically with hermetic connectors installed on the vacuum vessel. System level analyses were performed on working fluids, cycle design parameters, heater and cooling temperatures, and heat exchanger options that best meet the needs of the power converter specification. The goal is to provide a cost effective system that has high thermal-to-electric efficiency in a compact, lightweight package.

Introduction of a Current Waveform, Waveshaping Technique to Limit Conduction Loss in High-Frequency DC-DC Converters Suitable for Space Power

DTIC Science & Technology

1990-06-01

resonant Buck converter 19 ABSTRACT (Continue on reverse if necessary and identify by block number) Space power supply manufacturers have tried to...increase power density and construct smaller, highly efficient power supplies by increasing switching frequency. Incorporation of a power MOSFET as a...Michael, Second Reader \\’-. ohn P. Powers , Chairman Department of Electrical Engineering iii ABSTRACT Space power supply manufacturers have tried to

Electrical characterization of a Mapham inverter using pulse testing techniques

NASA Technical Reports Server (NTRS)

Baumann, E. D.; Myers, I. T.; Hammond, A. N.

1990-01-01

Electric power requirements for aerospace missions have reached megawatt power levels. Within the next few decades, it is anticipated that a manned lunar base, interplanetary travel, and surface exploration of the Martian surface will become reality. Several research and development projects aimed at demonstrating megawatt power level converters for space applications are currently underway at the NASA Lewis Research Center. Innovative testing techniques will be required to evaluate the components and converters, when developed, at their rated power in the absence of costly power sources, loads, and cooling systems. Facilities capable of testing these components and systems at full power are available, but their use may be cost prohibitive. The use of a multiple pulse testing technique is proposed to determine the electrical characteristics of large megawatt level power systems. Characterization of a Mapham inverter is made using the proposed technique and conclusions are drawn concerning its suitability as an experimental tool to evaluate megawatt level power systems.

Single Phase Passive Rectification Versus Active Rectification Applied to High Power Stirling Engines

NASA Technical Reports Server (NTRS)

Santiago, Walter; Birchenough, Arthur G.

2006-01-01

Stirling engine converters are being considered as potential candidates for high power energy conversion systems required by future NASA explorations missions. These types of engines typically contain two major moving parts, the displacer and the piston, in which a linear alternator is attached to the piston to produce a single phase sinusoidal waveform at a specific electric frequency. Since all Stirling engines perform at low electrical frequencies (less or equal to 100 Hz), space explorations missions that will employ these engines will be required to use DC power management and distribution (PMAD) system instead of an AC PMAD system to save on space and weight. Therefore, to supply such DC power an AC to DC converter is connected to the Stirling engine. There are two types of AC to DC converters that can be employed, a passive full bridge diode rectifier and an active switching full bridge rectifier. Due to the inherent line inductance of the Stirling Engine-Linear Alternator (SE-LA), their sinusoidal voltage and current will be phase shifted producing a power factor below 1. In order to keep power the factor close to unity, both AC to DC converters topologies will implement power factor correction. This paper discusses these power factor correction methods as well as their impact on overall mass for exploration applications. Simulation results on both AC to DC converters topologies with power factor correction as a function of output power and SE-LA line inductance impedance are presented and compared.

A review of the Thermoelectronic Laser Energy Converter /TELEC/ Program at Lewis Research Center

NASA Technical Reports Server (NTRS)

Alger, D. L.; Manista, E. J.; Thompson, R. W.

1978-01-01

The investigation of the Thermoelectronic Laser Energy Converter (TELEC) concept at the Lewis Research Center (LeRC) began with a feasibility study of a 1 megawatt sized TELEC system. The TELEC was to use either cesium vapor or hydrogen as the plasma medium. The cesium vapor TELEC appears to be the more practical device studied with an overall calculated conversion efficiency of greater than 48%. Following this study, a small TELEC cell was fabricated which demonstrated the conversion of a small amount of laser power to electrical power. The cell developed a short circuit current of 0.7 amperes and an open circuit voltage, as extrapolated from volt-ampere curves, of about 1.5 volts. Work is now in progress to construct and test a cesium vapor TELEC capable of absorbing 20% of an incident 10 kW, 10.6 micrometer beam, and converting 35% of this power to electrical power.

A new concept of space solar power satellite

NASA Astrophysics Data System (ADS)

Li, Xun; Duan, Baoyan; Song, Liwei; Yang, Yang; Zhang, Yiqun; Wang, Dongxu

2017-07-01

Space solar power satellite (SSPS) is a tremendous energy system that collects and converts solar power to electric power in space, and then transmits the electric power to earth wirelessly. In this paper, a novel SSPS concept based on ε-near-zero (ENZ) metamaterial is proposed. A spherical condenser made of ENZ metamaterial is developed, by using the refractive property of the ENZ metamaterial sunlight can be captured and redirected to its center. To make the geometric concentration ratio of the PV array reasonable, a hemispherical one located at the center is used to collect and convert the normal-incidence sunlight to DC power, then through a phased array transmitting antenna the DC power is beamed down to the rectenna on the ground. Detailed design of the proposed concept is presented.

ASPEC: Solar power satellite

NASA Technical Reports Server (NTRS)

1991-01-01

The solar power satellite (SPS) will provide a clean, reliable source of energy for large-scale consumption. The system will use satellites in geostationary orbits around the Earth to capture the Sun's energy. The intercepted sunlight will be converted to laser beam energy that can be transmitted to the Earth's surface. Ground systems on the Earth will convert the transmissions from space into electric power. The preliminary design for the SPS consists of one satellite in orbit around the Earth transmitting energy to a single ground station. The SPS design uses multilayer solar cell technology arranged on a 20 km squared planar array to intercept sunlight and convert it to an electric voltage. Power conditioning devices then send the electricity to a laser, which transmits the power to the surface of the Earth. A ground station will convert the beam into electricity. Typically, a single SPS will supply 5 GW of power to the ground station. Due to the large mass of the SPS, about 41 million kg, construction in space is needed in order to keep the structural mass low. The orbit configuration for this design is to operate a single satellite in geosynchronous orbit (GEO). The GEO allows the system to be positioned above a single receiving station and remain in sunlight 99 percent of the time. Construction will take place in low Earth orbit (LEO); array sections, 20 in total, will be sailed on solar wind out to the GEO location in 150 days. These individual transportation sections are referred to as solar sailing array panels (SSAP's). The primary truss elements used to support the array are composed of composite tubular members in a pentahedral arrangement. Smart segments consisting of passive and active damping devices will increase the control of dynamic SPS modes.

Mathematical modeling of a photovoltaic-laser energy converter for iodine laser radiation

NASA Technical Reports Server (NTRS)

Walker, Gilbert H.; Heinbockel, John H.

1987-01-01

Space-based laser power systems will require converters to change laser radiation into electricity. Vertical junction photovoltaic converters are promising devices for this use. A promising laser for the laser power station is the t-C4F9I laser which emits radiation at a wavelength of 1.315 microns. This paper describes the results of mathematical modeling of a photovoltaic-laser energy converter for use with this laser. The material for this photovoltaic converter is Ga(53)In(47)As which has a bandgap energy of 0.94 eV, slightly below the energy of the laser photons (0.943 eV). Results of a study optimizing the converter parameters are presented. Calculated efficiency for a 1000 vertical junction converter is 42.5 percent at a power density of 1 x 10 to the 3d power w/sq cm.

Small, Optically-Driven Power Source

NASA Technical Reports Server (NTRS)

Cockrum, Richard H.; Wang, Ke-Li J.

1988-01-01

Power transmitted along fiber-optic cables. Transmitted as infrared light along fiber-optic cable, converted to electricity to supply small electronic circuit. Power source and circuit remains electrically isolated from each other for safety or reduces electromagnetic interference. Array of diodes made by standard integrated-circuit techniques and packaged for mounting at end of fiber-optic cable.

An oscillating wave energy converter with nonlinear snap-through Power-Take-Off systems in regular waves

NASA Astrophysics Data System (ADS)

Zhang, Xian-tao; Yang, Jian-min; Xiao, Long-fei

2016-07-01

Floating oscillating bodies constitute a large class of wave energy converters, especially for offshore deployment. Usually the Power-Take-Off (PTO) system is a directly linear electric generator or a hydraulic motor that drives an electric generator. The PTO system is simplified as a linear spring and a linear damper. However the conversion is less powerful with wave periods off resonance. Thus, a nonlinear snap-through mechanism with two symmetrically oblique springs and a linear damper is applied in the PTO system. The nonlinear snap-through mechanism is characteristics of negative stiffness and double-well potential. An important nonlinear parameter γ is defined as the ratio of half of the horizontal distance between the two springs to the original length of both springs. Time domain method is applied to the dynamics of wave energy converter in regular waves. And the state space model is used to replace the convolution terms in the time domain equation. The results show that the energy harvested by the nonlinear PTO system is larger than that by linear system for low frequency input. While the power captured by nonlinear converters is slightly smaller than that by linear converters for high frequency input. The wave amplitude, damping coefficient of PTO systems and the nonlinear parameter γ affect power capture performance of nonlinear converters. The oscillation of nonlinear wave energy converters may be local or periodically inter well for certain values of the incident wave frequency and the nonlinear parameter γ, which is different from linear converters characteristics of sinusoidal response in regular waves.

Generation of electrical power

DOEpatents

Hursen, Thomas F.; Kolenik, Steven A.; Purdy, David L.

1976-01-01

A heat-to-electricity converter is disclosed which includes a radioactive heat source and a thermoelectric element of relatively short overall length capable of delivering a low voltage of the order of a few tenths of a volt. Such a thermoelectric element operates at a higher efficiency than longer higher-voltage elements; for example, elements producing 6 volts. In the generation of required power, thermoelectric element drives a solid-state converter which is controlled by input current rather than input voltage and operates efficiently for a high signal-plus-noise to signal ratio of current. The solid-state converter has the voltage gain necessary to deliver the required voltage at the low input of the thermoelectric element.

Automatic load sharing in inverter modules

NASA Technical Reports Server (NTRS)

Nagano, S.

1979-01-01

Active feedback loads transistor equally with little power loss. Circuit is suitable for balancing modular inverters in spacecraft, computer power supplies, solar-electric power generators, and electric vehicles. Current-balancing circuit senses differences between collector current for power transistor and average value of load currents for all power transistors. Principle is effective not only in fixed duty-cycle inverters but also in converters operating at variable duty cycles.

Magnetostrictive Alternator

NASA Technical Reports Server (NTRS)

Bruder, Geoffrey A. (Inventor); Dyson, Jr., Rodger W. (Inventor)

2018-01-01

A magnetostrictive alternator configured to convert pressure waves into electrical energy is provided. It should be appreciated that the magnetostrictive alternator may be combined in some embodiments with a Stirling engine to produce electrical power. The Stirling engine creates the oscillating pressure wave and the magnetostrictive alternator converts the pressure wave into electricity. In some embodiments, the magnetostrictive alternator may include aerogel material and magnetostrictive material. The aerogel material may be configured to convert a higher amplitude pressure wave into a lower amplitude pressure wave. The magnetostrictive material may be configured to generate an oscillating magnetic field when the magnetostrictive material is compressed by the lower amplitude pressure wave.

Hybrid electric vehicle power management system

DOEpatents

Bissontz, Jay E.

2015-08-25

Level voltage levels/states of charge are maintained among a plurality of high voltage DC electrical storage devices/traction battery packs that are arrayed in series to support operation of a hybrid electric vehicle drive train. Each high voltage DC electrical storage device supports a high voltage power bus, to which at least one controllable load is connected, and at least a first lower voltage level electrical distribution system. The rate of power transfer from the high voltage DC electrical storage devices to the at least first lower voltage electrical distribution system is controlled by DC-DC converters.

Tritium-field betacells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walko, R.J.; Lincoln, R.C.; Baca, W.E.

1991-01-01

Betavoltaic power sources operate by converting the nuclear decay energy of beta-emitting radioisotopes into electricity. Since they are not chemically driven, they could operate at temperatures which would either be to hot or too cold for typical chemical batteries. Further, for long lived isotopes, they offer the possibility of multi-decade active lifetimes. Two approaches are being investigated: direct and indirect conversion. Direct conversion cells consist of semiconductor diodes similar to photovoltaic cells. Beta particle directly bombard these cells, generating electron-hole pairs in the semiconductor which are converted to useful power. Many using low power flux beta emitters, wide bandgap semiconductorsmore » are required to achieve useful conversion efficiencies. The combination of tritium, as the beta emitter, and gallium phosphide (GaP), as the semiconductor converter, was evaluated. Indirect conversion betacells first convert the beta energy to light with a phosphor, and then to electricity with photovoltaic cells. An indirect conversion power source using a tritium radioluminescent (RL) light is being investigated. Our analysis indicates that this approach has the potential for significant volume and cost savings over the direct conversion method. 7 refs., 11 figs.« less

Tritium-field betacells

NASA Astrophysics Data System (ADS)

Walko, R. J.; Lincoln, R. C.; Baca, W. E.; Goods, S. H.; Negley, G. H.

Betavoltaic power sources operate by converting the nuclear decay energy of beta-emitting radioisotopes into electricity. Since they are not chemically driven, they could operate at temperatures which would either be too hot or too cold for typical chemical batteries. Further, for long lived isotopes, they offer the possibility of multi-decade active lifetimes. Two approaches are being investigated: direct and indirect conversion. Direct conversion cells consist of semiconductor diodes similar to photovoltaic cells. Beta particle directly bombard these cells, generating electron-hole pairs in the semiconductor which are converted to useful power. When using low power flux beta emitters, wide bandgap semiconductors are required to achieve useful conversion efficiencies. The combination of tritium, as the beta emitter, and gallium phosphide (GaP), as the semiconductor converter, was evaluated. Indirect conversion betacells first convert the beta energy to light with a phosphor, and then to electricity with photovoltaic cells. An indirect conversion power source using a tritium radioluminescent (RL) light is being investigated. Our analysis indicates that this approach has the potential for significant volume and cost savings over the direct conversion method.

Review on the conversion of thermoacoustic power into electricity.

PubMed

Timmer, Michael A G; de Blok, Kees; van der Meer, Theo H

2018-02-01

Thermoacoustic engines convert heat energy into high amplitude acoustic waves and subsequently into electric power. This article provides a review of the four main methods to convert the (thermo)acoustic power into electricity. First, loudspeakers and linear alternators are discussed in a section on electromagnetic devices. This is followed by sections on piezoelectric transducers, magnetohydrodynamic generators, and bidirectional turbines. Each segment provides a literature review of the given technology for the field of thermoacoustics, focusing on possible configurations, operating characteristics, output performance, and analytical and numerical methods to study the devices. This information is used as an input to discuss the performance and feasibility of each method, and to identify challenges that should be overcome for a more successful implementation in thermoacoustic engines. The work is concluded by a comparison of the four technologies, concentrating on the possible areas of application, the conversion efficiency, maximum electrical power output and more generally the suggested focus for future work in the field.

A collimator-converter system for IEC propulsion

NASA Astrophysics Data System (ADS)

Momota, Hiromu; Miley, George H.

2002-01-01

The collimator-converter system extracts fusion power from D-3He fueled IEC devices and provides electricity needed to operate ionic thrusters and other-power components. The whole system is linear and consists of a series of collimator units at the center, magnetic expander units at both sides of the fusion units, followed by direct energy converters at both ends. This system is enclosed in a vacuum chamber with a magnetic channel provided by magnetic solenoids out of respective chambers. The fusion unit consists of an IEC fusion core, a pair of coils anti-parallel to the solenoid coils, and a stabilization coil that stabilizes the position of coil pair coils. The IEC fusion core is installed at the center of the pair coils. After the magnetic expander, velocities of fusion particles from D-3He fueled IEC units are directed to the magnetic channel, which guides energetic fusion particles as well as leaking unburned fuel components to a high-efficiency traveling wave direct energy converter (TWDEC). Leaking unburned fuel components are separated with a magnetic separator at the entrance of a direct energy converter and pumped out for further refueling. A TWDEC is made of an array of metallic meshed grids, each of which is connected to every terminal with an external transmission circuit. The transmission line couples to the direct energy converter. Substations for electricity, a cryogenic plant, and various power control systems are outside of the vacuum chamber. The length of the cylindrical system is essentially determined by the proton energy of 14.8 MeV and the radius should be large so as to reduce power flow density. The present system provides 250 MWf fusion power and converting it to 150 MWc electricity. Its size is 150 m(length)×6.6 m(diameter) in size and 185 tons in weight. .

Construction and characterization of spherical Si solar cells combined with SiC electric power inverter

NASA Astrophysics Data System (ADS)

Oku, Takeo; Matsumoto, Taisuke; Hiramatsu, Kouichi; Yasuda, Masashi; Shimono, Akio; Takeda, Yoshikazu; Murozono, Mikio

2015-02-01

Spherical silicon (Si) photovoltaic solar cell systems combined with an electric power inverter using silicon carbide (SiC) field-effect transistor (FET) were constructed and characterized, which were compared with an ordinary Si-based converter. The SiC-FET devices were introduced in the direct current-alternating current (DC-AC) converter, which was connected with the solar panels. The spherical Si solar cells were used as the power sources, and the spherical Si panels are lighter and more flexible compared with the ordinary flat Si solar panels. Conversion efficiencies of the spherical Si solar cells were improved by using the SiC-FET.

Economic feasibility of converting cow manure to electricity: a case study of the CVPS Cow Power program in Vermont.

PubMed

Wang, Q; Thompson, E; Parsons, R; Rogers, G; Dunn, D

2011-10-01

A case study of the Central Vermont Public Service Corporation (CVPS) Cow Power program examines the economic feasibility for dairy farms to convert cow manure into electricity via anaerobic methane digestion. The study reviews the mechanism for CVPS, dairy farms, electricity customers, and government agencies to develop and operate the program since 2004, examines the costs and returns for the participating dairy farms, and assesses their cash flow over a period of 7 yr under different scenarios. With 6 dairy farms generating about 12 million kilowatt-hours of electricity per year and more than 4,600 CVPS electricity customers voluntarily paying premiums of $0.04 per kilowatt-hour, or a total of about $470,000 per year, the CVPS Cow Power program represents a successful and locally sourced renewable energy project with many environmental and economic benefits. Factors for the successful development and operation of the program include significant grants from government agencies and other organizations, strong consumer support, timely adjustments to the basic electricity price paid to the farms, and close collaboration among the participating parties. This study confirms that it is technically feasible to convert cow manure to electricity on farms, but the economic returns depend highly on the base electricity price, premium rate, financial supports from government agencies and other organizations, and sales of the byproducts of methane generation. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

AC power generation from microbial fuel cells

NASA Astrophysics Data System (ADS)

Lobo, Fernanda Leite; Wang, Heming; Forrestal, Casey; Ren, Zhiyong Jason

2015-11-01

Microbial fuel cells (MFCs) directly convert biodegradable substrates to electricity and carry good potential for energy-positive wastewater treatment. However, the low and direct current (DC) output from MFC is not usable for general electronics except small sensors, yet commercial DC-AC converters or inverters used in solar systems cannot be directly applied to MFCs. This study presents a new DC-AC converter system for MFCs that can generate alternating voltage in any desired frequency. Results show that AC power can be easily achieved in three different frequencies tested (1, 10, 60 Hz), and no energy storage layer such as capacitors was needed. The DC-AC converter efficiency was higher than 95% when powered by either individual MFCs or simple MFC stacks. Total harmonic distortion (THD) was used to investigate the quality of the energy, and it showed that the energy could be directly usable for linear electronic loads. This study shows that through electrical conversion MFCs can be potentially used in household electronics for decentralized off-grid communities.

The simulation of organic rankine cycle power plant with n-pentane working fluid

NASA Astrophysics Data System (ADS)

Nurhilal, Otong; Mulyana, Cukup; Suhendi, Nendi; Sapdiana, Didi

2016-02-01

In the steam power plant in Indonesia the dry steam from separator directly used to drive the turbin. Meanwhile, brine from the separator with low grade temperature reinjected to the earth. The brine with low grade temperature can be converted indirectly to electrical power by organic Rankine cycle (ORC) methods. In ORC power plant the steam are released from vaporization of organic working fluid by brine. The steam released are used to drive an turbine which in connected to generator to convert the mechanical energy into electric energy. The objective of this research is the simulation ORC power plant with n-pentane as organic working fluid. The result of the simulation for brine temperature around 165°C and the pressure 8.001 bar optained the net electric power around 1173 kW with the cycle thermal efficiency 14.61% and the flow rate of n-pentane around 15.51 kg/s. This result enable to applied in any geothermal source in Indonesia.

Electrical performance characteristics of high power converters for space power applications

NASA Technical Reports Server (NTRS)

Stuart, Thomas A.; King, Roger J.

1989-01-01

The first goal of this project was to investigate various converters that would be suitable for processing electric power derived from a nuclear reactor. The implementation is indicated of a 20 kHz system that includes a source converter, a ballast converter, and a fixed frequency converter for generating the 20 kHz output. This system can be converted to dc simply by removing the fixed frequency converter. This present study emphasized the design and testing of the source and ballast converters. A push-pull current-fed (PPCF) design was selected for the source converter, and a 2.7 kW version of this was implemented using three 900 watt modules in parallel. The characteristic equation for two converters in parallel was derived, but this analysis did not yield any experimental methods for measuring relative stability. The three source modules were first tested individually and then in parallel as a 2.7 kW system. All tests proved to be satisfactory; the system was stable; efficiency and regulation were acceptable; and the system was fault tolerant. The design of a ballast-load converter, which was operated as a shunt regulator, was investigated. The proposed power circuit is suitable for use with BJTs because proportional base drive is easily implemented. A control circuit which minimizes switching frequency ripple and automatically bypasses a faulty shunt section was developed. A nonlinear state-space-averaged model of the shunt regulator was developed and shown to produce an accurate incremental (small-signal) dynamic model, even though the usual state-space-averaging assumptions were not met. The nonlinear model was also shown to be useful for large-signal dynamic simulation using PSpice.

Efficiency limits of laser power converters for optical power transfer applications

NASA Astrophysics Data System (ADS)

Mukherjee, J.; Jarvis, S.; Perren, M.; Sweeney, S. J.

2013-07-01

We have developed III-V-based high-efficiency laser power converters (LPCs), optimized specifically for converting monochromatic laser radiation at the eye-safe wavelength of 1.55 µm into electrical power. The applications of these photovoltaic cells include high-efficiency space-based and terrestrial laser power transfer and subsequent conversion to electrical power. In addition, these cells also find use in fibre-optic power delivery, remote powering of subcutaneous equipment and several other optical power delivery applications. The LPC design is based on lattice-matched InGaAsP/InP and incorporates elements for photon-recycling and contact design for efficient carrier extraction. Here we compare results from electro-optical design simulations with experimental results from prototype devices studied both in the lab and in field tests. We analyse wavelength and temperature dependence of the LPC characteristics. An experimental conversion efficiency of 44.6% [±1%] is obtained from the prototype devices under monochromatic illumination at 1.55 µm (illumination power density of 1 kW m-2) at room temperature. Further design optimization of our LPC is expected to scale the efficiency beyond 50% at 1 kW m-2.

The construction, testing, and installation of a 6500 r/min 15 000-hp adjustable-speed electric drive for a centrifugal gas compressor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawrence, R.G.; Finney, D.; Davidson, D.F.

1988-07-01

The construction, testing, and installation of a 6500 r/min 15 000-hp adjustable-speed electric drive for a centrifugal gas compressor is presented. A power electronic converter is applied to control the speed of a 5-kV motor. The motor is directly coupled to a 6500 r/min compressor and replaced a steam turbine. Dual converters are used in a twelve-pulse arrangement at both the utility and the motor. The motor is of solid rotor construction, with dual 30/sup 0/ displaced stator windings. Finite-element analysis is used to optimize the motor designs for use with a variable-frequency static converter. Full-power tests are completed whichmore » confirm theoretical predictions on losses, performance, and operation. The electrical drive takes up considerably less space and is much more efficient than the steam turbine it replaced.« less

"Printed-circuit" rectenna

NASA Technical Reports Server (NTRS)

Dickinson, R. M.

1977-01-01

Rectifying antenna is less bulky structure for absorbing transmitted microwave power and converting it into electrical current. Printed-circuit approach, using microstrip technology and circularly polarized antenna, makes polarization orientation unimportant and allows much smaller arrays for given performance. Innovation is particularly useful with proposed electric vehicles powered by beam microwaves.

Low-Mass, Low-Power Hall Thruster System

NASA Technical Reports Server (NTRS)

Pote, Bruce

2015-01-01

NASA is developing an electric propulsion system capable of producing 20 mN thrust with input power up to 1,000 W and specific impulse ranging from 1,600 to 3,500 seconds. The key technical challenge is the target mass of 1 kg for the thruster and 2 kg for the power processing unit (PPU). In Phase I, Busek Company, Inc., developed an overall subsystem design for the thruster/cathode, PPU, and xenon feed system. This project demonstrated the feasibility of a low-mass power processing architecture that replaces four of the DC-DC converters of a typical PPU with a single multifunctional converter and a low-mass Hall thruster design employing permanent magnets. In Phase II, the team developed an engineering prototype model of its low-mass BHT-600 Hall thruster system, with the primary focus on the low-mass PPU and thruster. The goal was to develop an electric propulsion thruster with the appropriate specific impulse and propellant throughput to enable radioisotope electric propulsion (REP). This is important because REP offers the benefits of nuclear electric propulsion without the need for an excessively large spacecraft and power system.

Heat to electricity conversion by cold carrier emissive energy harvesters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strandberg, Rune

2015-12-07

This paper suggests a method to convert heat to electricity by the use of devices called cold carrier emissive energy harvesters (cold carrier EEHs). The working principle of such converters is explained and theoretical power densities and efficiencies are calculated for ideal devices. Cold carrier EEHs are based on the same device structure as hot carrier solar cells, but works in an opposite way. Whereas a hot carrier solar cell receives net radiation from the sun and converts some of this radiative heat flow into electricity, a cold carrier EEH sustains a net outflux of radiation to the surroundings whilemore » converting some of the energy supplied to it into electricity. It is shown that the most basic type of cold carrier EEHs have the same theoretical efficiency as the ideal emissive energy harvesters described earlier by Byrnes et al. In the present work, it is also shown that if the emission from the cold carrier EEH originates from electron transitions across an energy gap where a difference in the chemical potential of the electrons above and below the energy gap is sustained, power densities slightly higher than those given by Byrnes et al. can be achieved.« less

High Power Silicon Carbide (SiC) Power Processing Unit Development

NASA Technical Reports Server (NTRS)

Scheidegger, Robert J.; Santiago, Walter; Bozak, Karin E.; Pinero, Luis R.; Birchenough, Arthur G.

2015-01-01

NASA GRC successfully designed, built and tested a technology-push power processing unit for electric propulsion applications that utilizes high voltage silicon carbide (SiC) technology. The development specifically addresses the need for high power electronics to enable electric propulsion systems in the 100s of kilowatts. This unit demonstrated how high voltage combined with superior semiconductor components resulted in exceptional converter performance.

Harvesting dissipated energy with a mesoscopic ratchet

NASA Astrophysics Data System (ADS)

Roche, B.; Roulleau, P.; Jullien, T.; Jompol, Y.; Farrer, I.; Ritchie, D. A.; Glattli, D. C.

2015-04-01

The search for new efficient thermoelectric devices converting waste heat into electrical energy is of major importance. The physics of mesoscopic electronic transport offers the possibility to develop a new generation of nanoengines with high efficiency. Here we describe an all-electrical heat engine harvesting and converting dissipated power into an electrical current. Two capacitively coupled mesoscopic conductors realized in a two-dimensional conductor form the hot source and the cold converter of our device. In the former, controlled Joule heating generated by a voltage-biased quantum point contact results in thermal voltage fluctuations. By capacitive coupling the latter creates electric potential fluctuations in a cold chaotic cavity connected to external leads by two quantum point contacts. For unequal quantum point contact transmissions, a net electrical current is observed proportional to the heat produced.

Cycling firing method for bypass operation of bridge converters

DOEpatents

Zabar, Zivan

1982-01-01

The bridge converter comprises a number of switching elements and an electronic logic system which regulated the electric power levels by controlling the firing, i.e., the initiation of the conduction period of the switching elements. Cyclic firing of said elements allows the direct current to bypass the alternating current system with high power factor and negligible losses.

Automatic control in multidrive electrotechnical complexes with semiconductor converters

NASA Astrophysics Data System (ADS)

Vasilev, B. U.; Mardashov, D. V.

2017-01-01

The frequency convertor and the automatic control system, which can be used in the multi-drive electromechanical system with a few induction motions, are considered. The paper presents the structure of existing modern multi-drive electric drives inverters, namely, electric drives with a total frequency converter and few electric motions, and an electric drive, in which the converter is used for power supply and control of the independent frequency. It was shown that such technical solutions of frequency converters possess a number of drawbacks. The drawbacks are given. It was shown that the control of technological processes using the electric drive of this structure may be provided under very limited conditions, as the energy efficiency and the level of electromagnetic compatibility of electric drives is low. The authors proposed using a multi-inverter structure with an active rectifier in multidrive electric drives with induction motors frequency converters. The application of such frequency converter may solve the problem of electromagnetic compatibility, namely, consumption of sinusoidal currents from the network and the maintenance of a sinusoidal voltage and energy compatibility, namely, consumption of practically active energy from the network. Also, the paper proposes the use of the automatic control system, which by means of a multi-inverter frequency converter provides separate control of drive machines and flexible regulation of technological processes. The authors present oscillograms, which confirm the described characteristics of the developed electrical drive. The possible subsequent ways to improve the multi-motor drives are also described.

Stability test for power converters in high-powered operations for J-PARC MR main magnets

NASA Astrophysics Data System (ADS)

Morita, Yuichi; Kurimoto, Yoshinori; Miura, Kazuki; Sagawa, Ryu; Shimogawa, Tetsushi

2017-10-01

The Japan Proton Accelerator Research Complex (J-PARC) aims at achieving a megawatt-class proton accelerator facility. One promising method for increasing the beam power is to shorten the repetition cycle of the main ring from the current cycle of 2.48 s to 1.3 s. In this scheme, however, the increase in the output voltage and the power variation of the electric system are serious concerns for the power supplies of the main magnets. We have been developing a new power supply that provides solutions to these issues. Recently, we proposed a new method for high-powered tests of the converter that does not require a large-scale load and power source. We carried out a high-powered test of ∼100 kVA for the prototype DC/DC converters of the new power supply with this method. This paper introduces the design of the power supply and the results of the high-powered test for the prototype DC/DC converters.

Effect of power shape on energy extraction from microbial fuel cell

NASA Astrophysics Data System (ADS)

Alaraj, Muhannad; Feng, Shuo; Roane, Timberley M.; Park, Jae-Do

2017-10-01

Microbial fuel cells (MFCs) generate renewable energy in the form of direct current (DC) power. Harvesting energy from MFCs started with passive components such as resistors and capacitors, then charge pumps were introduced with some more advantages. Power electronics converters were later preferred due to their higher efficiency and controllability; however, they introduce high frequency current ripple due to their high frequency switching. In this paper, the effect of shape of power extraction on MFC performance was investigated using three types of current shapes: continuous, square-wave, and triangular-wave. Simultaneously, chemical parameters, such as pH, dissolved oxygen, electrical conductivity, and redox potential, in the anode chamber were monitored to see how these parameters change with the shape of the electrical power extraction. Results showed that the shape of the extracted current did not have a substantial effect on the MFC life span, output power, and energy extraction, nor on the chemical parameters. The outcome of this study provided insight for the electrical impact by power electronics converters on some microbial and chemical aspects of an MFC system.

AMTEC Generator: Phase 1 Propane System

DTIC Science & Technology

2002-10-15

Final Report 15 October 2002 17 Figure 18. Model Predictions with a 28W Gross AMTEC Converter, 27 g/hr, 8.3% Overall Efficiency 5 10 15...hot) (C ) fuel flow rate (mg/s) efficiency electrical output cell hot temp Design point: cell power = 28.3 W η thermal = 8.3% fuel flow rate = 7.4...Metal Thermal to Electric Conversion ( AMTEC ) technology converts the heat from

Power generation by thermally assisted electroluminescence: like optical cooling, but different

NASA Astrophysics Data System (ADS)

Buckner, Benjamin D.; Heeg, Bauke

2008-02-01

Thermally assisted electro-luminescence may provide a means to convert heat into electricity. In this process, radiation from a hot light-emitting diode (LED) is converted to electricity by a photovoltaic (PV) cell, which is termed thermophotonics. Novel analytical solutions to the equations governing such a system show that this system combines physical characteristics of thermophotovoltaics (TPV) and the inverse process of laser cooling. The flexibility of having both adjustable bias and load parameters may allow an optimized power generation system based on this concept to exceed the power throughput and efficiency of TPV systems. Such devices could function as efficient solar thermal, waste heat, and fuel-based generators.

Overview and future direction for blackbody solar-pumped lasers

NASA Technical Reports Server (NTRS)

Deyoung, R. J.

1988-01-01

A review of solar-pumped blackbody lasers is given which addresses their present status and suggests future research directions. The blackbody laser concept is one system proposed to scale to multimegawatt power levels for space-to-space power transmissions for such applications as onboard spacecraft electrical or propulsion needs. Among the critical technical issues are the scalability to high powers and the laser wavelength which impacts the transmission optics size as well as the laser-to-electric converter at the receiver. Because present blackbody solar-pumped lasers will have laser wavelengths longer than 4 microns, simple photovoltaic converters cannot be used, and transmission optics will be large. Thus, future blackbody laser systems should emphasize near visible laser wavelengths.

Resonant wave energy harvester based on dielectric elastomer generator

NASA Astrophysics Data System (ADS)

Moretti, Giacomo; Pietro Rosati Papini, Gastone; Righi, Michele; Forehand, David; Ingram, David; Vertechy, Rocco; Fontana, Marco

2018-03-01

Dielectric elastomer generators (DEGs) are a class of capacitive solid-state devices that employ highly stretchable dielectrics and conductors to convert mechanical energy into high-voltage direct-current electricity. Their promising performance in terms of convertible energy and power density has been mostly proven in quasi-static experimental tests with prescribed deformation. However, the assessment of their ability in harvesting energy from a dynamic oscillating source of mechanical energy is crucial to demonstrate their effectiveness in practical applications. This paper reports a first demonstration of a DEG system that is able to convert the oscillating energy carried by water waves into electricity. A DEG prototype is built using a commercial polyacrylate film (VHB 4905 by 3M) and an experimental campaign is conducted in a wave-flume facility, i.e. an artificial basin that makes it possible to generate programmed small-scale waves at different frequencies and amplitudes. In resonant conditions, the designed system demonstrates the delivery of a maximum of 0.87 W of electrical power output and 0.64 J energy generated per cycle, with corresponding densities per unit mass of dielectric elastomer of 197 W kg-1 and 145 J kg-1. Additionally, a notable maximum fraction of 18% of the input wave energy is converted into electricity. The presented results provide a promising demonstration of the operation and effectiveness of ocean wave energy converters based on elastic capacitive generators.

20--500 watt AMTEC auxiliary electric power system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ivanenok, J.F. III; Sievers, R.K.

1996-12-31

Numerous design studies have been completed on Alkali Metal Thermal to Electric Converter (AMTEC) power systems for space applications demonstrating their substantial increase in performance. Recently design studies have been initiated to couple AMTEC power conversion with fossil fueled combustion systems. This paper describes the results of a Phase 1 SBIR effort to design an innovative, efficient, reliable, long life AMTEC Auxiliary Electric Power System (AEPS) for remote site applications (20--500 watts). The concept uses high voltage AMTEC cells, each containing 7 to 9 small electrolyte tubes, integrated with a combustor and recuperator. These multi-tube AMTEC cells are low cost,more » reliable, long life static converters. AMTEC technology is ideal for auxiliary electric power supplies that must operate reliably over a broad range of temperatures, fuel sources, power levels, and operational specifications. The simplicity, efficiency (20% systems) and modularity of this technology allow it to fill applications as varied as light-weight backpacks, remote site power supplies, and military base power. Phase 1 demonstrated the feasibility of a 20% system design, and showed that the development needs to focus on identifying long life AMTEC cell components, determining the AMTEC cell and system reliability, and demonstrating that a 20 watt AMTEC system is 3--5 times more efficient than existing systems for the same application.« less

Multiport power router and its impact on future smart grids

NASA Astrophysics Data System (ADS)

Kado, Yuichi; Shichijo, Daiki; Wada, Keiji; Iwatsuki, Katsumi

2016-07-01

We propose a Y configuration power router as a unit cell to easily construct a power delivery system that can meet many types of user requirements. The Y configuration power router controls the direction and magnitude of power flows between three ports regardless of DC or AC. We constructed a prototype three-way isolated DC/DC converter that is the core unit of the Y configuration power router. The electrical insulation between three ports assures safety and reliability for power network systems. We then tested the operation of power flow control. The experimental results revealed that our methodology based on a governing equation was appropriate to control the power flow of the three-way DC/DC converter. In addition, a distribution network composed of power routers had the ability to easily enable interchanges of electrical power between autonomous microgrid cells. We also explored the requirements for communication between energy routers to achieve dynamic adjustments of energy flows in a coordinated manner and their impact on resilient power grid systems.

Testing of the Engineering Model Electrical Power Control Unit for the Fluids and Combustion Facility

NASA Technical Reports Server (NTRS)

Kimnach, Greg L.; Lebron, Ramon C.; Fox, David A.

1999-01-01

The John H. Glenn Research Center at Lewis Field (GRC) in Cleveland, OH and the Sundstrand Corporation in Rockford, IL have designed and developed an Engineering Model (EM) Electrical Power Control Unit (EPCU) for the Fluids Combustion Facility, (FCF) experiments to be flown on the International Space Station (ISS). The EPCU will be used as the power interface to the ISS power distribution system for the FCF's space experiments'test and telemetry hardware. Furthermore. it is proposed to be the common power interface for all experiments. The EPCU is a three kilowatt 12OVdc-to-28Vdc converter utilizing three independent Power Converter Units (PCUs), each rated at 1kWe (36Adc @ 28Vdc) which are paralleled and synchronized. Each converter may be fed from one of two ISS power channels. The 28Vdc loads are connected to the EPCU output via 48 solid-state and current-limiting switches, rated at 4Adc each. These switches may be paralleled to supply any given load up to the 108Adc normal operational limit of the paralleled converters. The EPCU was designed in this manner to maximize allocated-power utilization. to shed loads autonomously, to provide fault tolerance. and to provide a flexible power converter and control module to meet various ISS load demands. Tests of the EPCU in the Power Systems Facility testbed at GRC reveal that the overall converted-power efficiency, is approximately 89% with a nominal-input voltage of 12OVdc and a total load in the range of 4O% to 110% rated 28Vdc load. (The PCUs alone have an efficiency of approximately 94.5%). Furthermore, the EM unit passed all flight-qualification level (and beyond) vibration tests, passed ISS EMI (conducted, radiated. and susceptibility) requirements. successfully operated for extended periods in a thermal/vacuum chamber, was integrated with a proto-flight experiment and passed all stability and functional requirements.

Design of a high voltage input - output ratio dc-dc converter dedicated to small power fuel cell systems

NASA Astrophysics Data System (ADS)

Béthoux, O.; Cathelin, J.

2010-12-01

Consuming chemical energy, fuel cells produce simultaneously heat, water and useful electrical power [J.M. Andújar, F. Segura, Renew. Sust. Energy Rev. 13, 2309 (2009)], [J. Larminie, A. Dicks, Fuel Cell Systems Explained, 2nd edn. (John Wiley & Sons, 2003)]. As a matter of fact, the voltage generated by a fuel cell strongly depends on both the load power demand and the operating conditions. Besides, as a result of many design aspects, fuel cells are low voltage and high current electric generators. On the contrary, electric loads are commonly designed for small voltage swing and a high V/I ratio in order to minimize Joule losses. Therefore, electric loads supplied by fuel cells are typically fed by means of an intermediate power voltage regulator. The specifications of such a power converter are to be able to step up the input voltage with a high ratio (a ratio of 10 is a classic situation) and also to work with an excellent efficiency (in order to minimize its size, its weight and its losses) [A. Shahin, B. Huang, J.P. Martin, S. Pierfederici, B. Davat, Energy Conv. Manag. 51, 56 (2010)]. This paper deals with the design of this essential ancillary device. It intends to bring out the best structure for fulfilling this function. Several dc-dc converters with large voltage step-up ratios are introduced. A topology based on a coupled inductor or tapped inductor is closely studied. A detailed modelling is performed with the purpose of providing designing rules. This model is validated with both simulation and implementation. The experimental prototype is based on the following specifications: the fuel cell output voltage ranges from a 50 V open-voltage to a 25 V rated voltage while the load requires a constant 250 V voltage. The studied coupled inductor converter is compared with a classic boost converter commonly used in this voltage elevating application. Even though the voltage regulator faces severe FC specifications, the measured efficiency reaches 96% at the rated power whereas conventional boost efficiency barely achieves 91.5% in the same operating conditions.

Fundamentals of Electrical Propulsion Plant Design,

DTIC Science & Technology

1982-04-06

through connection of resonant filters or through use of multiphase conversion power circuits. Figure 9.25. Block Diagram of a Frequency Converter Control...first harmonic, active power Pa’ consumed by the converter at the point of application of this emf, is determined from expression P. = 3EM i cos i...armature shunting contactor K3 KDD diesel starting contactor K.U KZ protection contactor K3 KMM maximum power contactor KM KO compensating winding KO

A Power Conversion Concept for the Jupiter Icy Moons Orbiter

NASA Technical Reports Server (NTRS)

Mason, Lee S.

2003-01-01

The Jupiter Icy Moons Orbiter (JIMO) mission is currently under study by the Office of Space Science under the Project Prometheus Program. JIMO is examining the use of Nuclear Electric Propulsion (NEP) to carry scientific payloads to three Jovian moons. A potential power system concept includes dual 100 kWe Brayton converters, a deployable pumped loop heat rejection subsystem, and a 400 Vac Power Management and Distribution (PMAD) bus. Many trades were performed in aniving at this candidate power system concept. System-level studies examined design and off-design operating modes, determined startup requirements, evaluated subsystem redundancy options, and quantified the mass and radiator area of reactor power systems from 20 to 200 kWe. In the Brayton converter subsystem, studies were performed to investigate converter packaging options, and assess the induced torque effects on spacecraft dynamics due to rotating machinery. In the heat rejection subsystem, design trades were conducted on heat transport approaches, material and fluid options, and deployed radiator geometries. In the PMAD subsystem, the overall electrical architecture was defined and trade studies examined distribution approaches, voltage levels, and cabling options.

Modulation and control of matrix converter for aerospace application

NASA Astrophysics Data System (ADS)

Kobravi, Keyhan

In the context of modern aircraft systems, a major challenge is power conversion to supply the aircraft's electrical instruments. These instruments are energized through a fixed-frequency internal power grid. In an aircraft, the available sources of energy are a set of variable-speed generators which provide variable-frequency ac voltages. Therefore, to energize the internal power grid of an aircraft, the variable-frequency ac voltages should be converted to a fixed-frequency ac voltage. As a result, an ac to ac power conversion is required within an aircraft's power system. This thesis develops a Matrix Converter to energize the aircraft's internal power grid. The Matrix Converter provides a direct ac to ac power conversion. A major challenge of designing Matrix Converters for aerospace applications is to minimize the volume and weight of the converter. These parameters are minimized by increasing the switching frequency of the converter. To design a Matrix Converter operating at a high switching frequency, this thesis (i) develops a scheme to integrate fast semiconductor switches within the current available Matrix Converter topologies, i.e., MOSFET-based Matrix Converter, and (ii) develops a new modulation strategy for the Matrix Converter. This Matrix Converter and the new modulation strategy enables the operation of the converter at a switching-frequency of 40kHz. To provide a reliable source of energy, this thesis also develops a new methodology for robust control of Matrix Converter. To verify the performance of the proposed MOSFET-based Matrix Converter, modulation strategy, and control design methodology, various simulation and experimental results are presented. The experimental results are obtained under operating condition present in an aircraft. The experimental results verify the proposed Matrix Converter provides a reliable power conversion in an aircraft under extreme operating conditions. The results prove the superiority of the proposed Matrix Converter technology for ac to ac power conversion regarding the existing technologies of Matrix Converters.

Multi Bus DC-DC Converter in Electric Hybrid Vehicles

NASA Astrophysics Data System (ADS)

Krithika, V.; Subramaniam, C.; Sridharan, R.; Geetha, A.

2018-04-01

This paper is cotncerned with the design, simulation and fabrication of the prototype of a Multi bus DC- DC converter operating from 42V DC and delivering 14V DC and 260V DC. As a result, three DC buses are interconnected through a single power electronic circuitry. Such a requirement is energized in the development of a hybrid electric automobile which uses the technology of fuel cell. This is implemented by using a Bidirectional DC-DC converter configuration which is ideally suitable for multiple outputs with mutual electrical isolation. For the sake of reduced size and cost of step-up transformer, selection of a high frequency switching cycle at 10 KHz was done.

Improvement in thermoelectric power factor of mechanically alloyed p-type SiGe by incorporation of TiB{sub 2}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahmad, Sajid, E-mail: sajidahmadiitkgp@gmail.com; Dubey, K.; Bhattacharya, Shovit

2016-05-23

Nearly 60% of the world’s useful energy is wasted as heat and recovering a fraction of this waste heat by converting it as useful electrical power is an important area of research{sup [1]}. Thermoelectric power generators (TEG) are solid state devices which converts heat into electricity. TEG consists of n and p-type thermoelements connected electrically in series and thermally in parallel{sup [2]}. Silicon germanium (SiGe) alloy is one of the conventional high temperature thermoelectric materials and is being used in radio-isotopes based thermoelectric power generators for deep space exploration programs.Temperature (T) dependence of thermoelectric (TE) properties of p-type SiGe andmore » p-type SiGe-x wt.%TiB{sub 2} (x=6,8,10%) nanocomposite materials has been studied with in the temperature range of 300 K to 1100 K. It is observed that there is an improvement in the power factor (α{sup 2}/ρ) of SiGe alloy on addition of TiB{sub 2} upto 8 wt.% that is mainly due to increase in the Seebeck coefficient (α) and electrical conductivity (σ) of the alloy.« less

Analysis of Electric Vehicle DC High Current Conversion Technology

NASA Astrophysics Data System (ADS)

Yang, Jing; Bai, Jing-fen; Lin, Fan-tao; Lu, Da

2017-05-01

Based on the background of electric vehicles, it is elaborated the necessity about electric energy accurate metering of electric vehicle power batteries, and it is analyzed about the charging and discharging characteristics of power batteries. It is needed a DC large current converter to realize accurate calibration of power batteries electric energy metering. Several kinds of measuring methods are analyzed based on shunts and magnetic induction principle in detail. It is put forward power batteries charge and discharge calibration system principle, and it is simulated and analyzed ripple waves containing rate and harmonic waves containing rate of power batteries AC side and DC side. It is put forward suitable DC large current measurement methods of power batteries by comparing different measurement principles and it is looked forward the DC large current measurement techniques.

Advanced Direct-Drive Generator for Improved Availability of Oscillating Wave Surge Converter Power Generation Systems Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Englebretson, Steven; Ouyang, Wen; Tschida, Colin

This report summarizes the activities conducted under the DOE-EERE funded project DE-EE0006400, where ABB Inc. (ABB), in collaboration with Texas A&M’s Advanced Electric Machines & Power Electronics (EMPE) Lab and Resolute Marine Energy (RME) designed, derisked, developed, and demonstrated a novel magnetically geared electrical generator for direct-drive, low-speed, high torque MHK applications The project objective was to investigate a novel and compact direct-drive electric generator and its system aspects that would enable elimination of hydraulic components in the Power Take-Off (PTO) of a Marine and Hydrokinetic (MHK) system with an oscillating wave surge converter (OWSC), thereby improving the availability ofmore » the MHK system. The scope of this project was limited to the development and dry lab demonstration of a low speed generator to enable future direct drive MHK systems.« less

Utility-Scale Solar Power Converter: Agile Direct Grid Connect Medium Voltage 4.7-13.8 kV Power Converter for PV Applications Utilizing Wide Band Gap Devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

Solar ADEPT Project: Satcon is developing a compact, lightweight power conversion device that is capable of taking utility-scale solar power and outputting it directly into the electric utility grid at distribution voltage levels—eliminating the need for large transformers. Transformers “step up” the voltage of the power that is generated by a solar power system so it can be efficiently transported through transmission lines and eventually “stepped down” to usable voltages before it enters homes and businesses. Power companies step up the voltage because less electricity is lost along transmission lines when the voltage is high and current is low. Satcon’smore » new power conversion devices will eliminate these heavy transformers and connect a utility-scale solar power system directly to the grid. Satcon’s modular devices are designed to ensure reliability—if one device fails it can be bypassed and the system can continue to run.« less

Subsystem design in aircraft power distribution systems using optimization

NASA Astrophysics Data System (ADS)

Chandrasekaran, Sriram

2000-10-01

The research reported in this dissertation focuses on the development of optimization tools for the design of subsystems in a modern aircraft power distribution system. The baseline power distribution system is built around a 270V DC bus. One of the distinguishing features of this power distribution system is the presence of regenerative power from the electrically driven flight control actuators and structurally integrated smart actuators back to the DC bus. The key electrical components of the power distribution system are bidirectional switching power converters, which convert, control and condition electrical power between the sources and the loads. The dissertation is divided into three parts. Part I deals with the formulation of an optimization problem for a sample system consisting of a regulated DC-DC buck converter preceded by an input filter. The individual subsystems are optimized first followed by the integrated optimization of the sample system. It is shown that the integrated optimization provides better results than that obtained by integrating the individually optimized systems. Part II presents a detailed study of piezoelectric actuators. This study includes modeling, optimization of the drive amplifier and the development of a current control law for piezoelectric actuators coupled to a simple mechanical structure. Linear and nonlinear methods to study subsystem interaction and stability are studied in Part III. A multivariable impedance ratio criterion applicable to three phase systems is proposed. Bifurcation methods are used to obtain global stability characteristics of interconnected systems. The application of a nonlinear design methodology, widely used in power systems, to incrementally improve the robustness of a system to Hopf bifurcation instability is discussed.

Hybridizing energy conversion and storage in a mechanical-to-electrochemical process for self-charging power cell.

PubMed

Xue, Xinyu; Wang, Sihong; Guo, Wenxi; Zhang, Yan; Wang, Zhong Lin

2012-09-12

Energy generation and energy storage are two distinct processes that are usually accomplished using two separated units designed on the basis of different physical principles, such as piezoelectric nanogenerator and Li-ion battery; the former converts mechanical energy into electricity, and the latter stores electric energy as chemical energy. Here, we introduce a fundamental mechanism that directly hybridizes the two processes into one, in which the mechanical energy is directly converted and simultaneously stored as chemical energy without going through the intermediate step of first converting into electricity. By replacing the polyethylene (PE) separator as for conventional Li battery with a piezoelectric poly(vinylidene fluoride) (PVDF) film, the piezoelectric potential from the PVDF film as created by mechanical straining acts as a charge pump to drive Li ions to migrate from the cathode to the anode accompanying charging reactions at electrodes. This new approach can be applied to fabricating a self-charging power cell (SCPC) for sustainable driving micro/nanosystems and personal electronics.

Study of a thermoelectric system equipped with a maximum power point tracker for stand-alone electric generation.

NASA Astrophysics Data System (ADS)

Favarel, C.; Champier, D.; Bédécarrats, J. P.; Kousksou, T.; Strub, F.

2012-06-01

According to the International Energy Agency, 1.4 billion people are without electricity in the poorest countries and 2.5 billion people rely on biomass to meet their energy needs for cooking in developing countries. The use of cooking stoves equipped with small thermoelectric generator to provide electricity for basic needs (LED, cell phone and radio charging device) is probably a solution for houses far from the power grid. The cost of connecting every house with a landline is a lot higher than dropping thermoelectric generator in each house. Thermoelectric generators have very low efficiency but for isolated houses, they might become really competitive. Our laboratory works in collaboration with plane`te-bois (a non governmental organization) which has developed energy-efficient multifunction (cooking and hot water) stoves based on traditional stoves designs. A prototype of a thermoelectric generator (Bismuth Telluride) has been designed to convert a small part of the energy heating the sanitary water into electricity. This generator can produce up to 10 watts on an adapted load. Storing this energy in a battery is necessary as the cooking stove only works a few hours each day. As the working point of the stove varies a lot during the use it is also necessary to regulate the electrical power. An electric DC DC converter has been developed with a maximum power point tracker (MPPT) in order to have a good efficiency of the electronic part of the thermoelectric generator. The theoretical efficiency of the MMPT converter is discussed. First results obtained with a hot gas generator simulating the exhaust of the combustion chamber of a cooking stove are presented in the paper.

Measuring Power Flow in Electric Vehicles

NASA Technical Reports Server (NTRS)

Griffin, Daniel C., Jr; Wiker, G. A.

1983-01-01

Instrument accommodates fast rise and fall times of waveforms characteristic of modern, efficient power controllers. Power meter multiplies analog signals proportional to voltage and current, and converts resulting signal to frequency. Two mechanical counters provided: one for charging, one for discharging.

Auxiliary quasi-resonant dc tank electrical power converter

DOEpatents

Peng, Fang Z.

2006-10-24

An auxiliary quasi-resonant dc tank (AQRDCT) power converter with fast current charging, voltage balancing (or charging), and voltage clamping circuits is provided for achieving soft-switched power conversion. The present invention is an improvement of the invention taught in U.S. Pat. No. 6,111,770, herein incorporated by reference. The present invention provides faster current charging to the resonant inductor, thus minimizing delay time of the pulse width modulation (PWM) due to the soft-switching process. The new AQRDCT converter includes three tank capacitors or power supplies to achieve the faster current charging and minimize the soft-switching time delay. The new AQRDCT converter further includes a voltage balancing circuit to charge and discharge the three tank capacitors so that additional isolated power supplies from the utility line are not needed. A voltage clamping circuit is also included for clamping voltage surge due to the reverse recovery of diodes.

Component technology for stirling power converters

NASA Technical Reports Server (NTRS)

Thieme, Lanny G.

1991-01-01

NASA Lewis Research Center has organized a component technology program as part of the efforts to develop Stirling converter technology for space power applications. The Stirling Space Power Program is part of the NASA High Capacity Power Project of the Civil Space Technology Initiative (CSTI). NASA Lewis is also providing technical management for the DOE/Sandia program to develop Stirling converters for solar terrestrial power producing electricity for the utility grid. The primary contractors for the space power and solar terrestrial programs develop component technologies directly related to their goals. This Lewis component technology effort, while coordinated with the main programs, aims at longer term issues, advanced technologies, and independent assessments. An overview of work on linear alternators, engine/alternator/load interactions and controls, heat exchangers, materials, life and reliability, and bearings is presented.

Solar power satellites - Heat engine or solar cells

NASA Technical Reports Server (NTRS)

Oman, H.; Gregory, D. L.

1978-01-01

A solar power satellite is the energy-converting element of a system that can deliver some 10 GW of power to utilities on the earth's surface. We evaluated heat engines and solar cells for converting sunshine to electric power at the satellite. A potassium Rankine cycle was the best of the heat engines, and 50 microns thick single-crystal silicon cells were the best of the photovoltaic converters. Neither solar cells nor heat engines had a clear advantage when all factors were considered. The potassium-turbine power plant, however, was more difficult to assemble and required a more expensive orbital assembly base. We therefore based our cost analyses on solar-cell energy conversion, concluding that satellite-generated power could be delivered to utilities for around 4 to 5 cents a kWh.

Understanding Power Electronics and Electrical Machines in Multidisciplinary Wind Energy Conversion System Courses

ERIC Educational Resources Information Center

Duran, M. J.; Barrero, F.; Pozo-Ruz, A.; Guzman, F.; Fernandez, J.; Guzman, H.

2013-01-01

Wind energy conversion systems (WECS) nowadays offer an extremely wide range of topologies, including various different types of electrical generators and power converters. Wind energy is also an application of great interest to students and with a huge potential for engineering employment. Making WECS the main center of interest when teaching…

Energy 101: Wind Turbines - 2014 Update

ScienceCinema

None

2018-05-11

See how wind turbines generate clean electricity from the power of wind. The video highlights the basic principles at work in wind turbines, and illustrates how the various components work to capture and convert wind energy to electricity. This updated version also includes information on the Energy Department's efforts to advance offshore wind power. Offshore wind energy footage courtesy of Vestas.

Energy 101: Solar PV

ScienceCinema

None

2018-01-08

Solar photovoltaic (PV) systems can generate clean, cost-effective power anywhere the sun shines. This video shows how a PV panel converts the energy of the sun into renewable electricity to power homes and businesses.

H2-O2 combustion powered steam-MHD central power systems

NASA Technical Reports Server (NTRS)

Seikel, G. R.; Smith, J. M.; Nichols, L. D.

1974-01-01

Estimates are made for both the performance and the power costs of H2-O2 combustion powered steam-MHD central power systems. Hydrogen gas is assumed to be transmitted by pipe from a remote coal gasifier into the city and converted to electricity in a steam MHD plant having an integral gaseous oxygen plant. These steam MHD systems appear to offer an attractive alternative to both in-city clean fueled conventional steam power plants and to remote coal fired power plants with underground electric transmission into the city.

Connected vehicle assessment. Vehicle electrification and the smart grid : the supporting role of safety and mobility services.

DOT National Transportation Integrated Search

2013-01-01

Electric Vehicles are the only type of cars that get cleaner over time, as electrical power generation begins to convert slowly over time to lower-polluting energy sources. Hybrids, plug-in hybrids, and battery electrics are conservatively esti...

Comparison of advanced engines for parabolic dish solar thermal power plants

NASA Technical Reports Server (NTRS)

Fujita, T.; Bowyer, J. M.; Gajanana, B. C.

1980-01-01

A paraboloidal dish solar thermal power plant produces electrical energy by a two-step conversion process. The collector subsystem is composed of a two-axis tracking paraboloidal concentrator and a cavity receiver. The concentrator focuses intercepted sunlight (direct, normal insolation) into a cavity receiver whose aperture encircles the focal point of the concentrator. At the internal wall of the receiver the electromagnetic radiation is converted to thermal energy. A heat engine/generator assembly then converts the thermal energy captured by the receiver to electricity. Developmental activity has been concentrated on small power modules which employ 11- to 12-meter diameter dishes to generate nominal power levels of approximately 20 kWe. A comparison of advanced heat engines for the dish power module is presented in terms of the performance potential of each engine with its requirements for advanced technology development. Three advanced engine possibilities are the Brayton (gas turbine), Brayton/Rankine combined cycle, and Stirling engines.

Thermionic cogeneration burner design

NASA Astrophysics Data System (ADS)

Miskolczy, G.; Goodale, D.; Moffat, A. L.; Morgan, D. T.

Since thermionic converters receive heat at very high temperatures (approximately 1800 K) and reject heat at moderately high temperatures (approximately 800 K), they are useful for cogeneration applications involving high temperature processes. The electric power from thermionic converters is produced as a high amperage, low-voltage direct current. An ideal cogeneration application would be to utilize the reject heat at the collector temperature and the electricity without power conditioning. A cogeneration application in the edible oil industry fulfills both of these requirements since both direct heat and hydrogen gas are required in the hydrogenation of the oils. In this application, the low-voltage direct current would be used in a hydrogen electrolyzer.

Investigation of a generator system for generating electrical power, to supply directly to the public network, using a windmill

NASA Technical Reports Server (NTRS)

Tromp, C.

1979-01-01

A windpowered generator system is described which uses a windmill to convert mechanical energy to electrical energy for a three phase (network) voltage of constant amplitude and frequency. The generator system controls the windmill by the number of revolutions so that the power drawn from the wind for a given wind velocity is maximum. A generator revolution which is proportional to wind velocity is achieved. The stator of the generator is linked directly to the network and a feed converter at the rotor takes care of constant voltage and frequency at the stator.

Early Oscillation Detection for DC/DC Converter Fault Diagnosis

NASA Technical Reports Server (NTRS)

Wang, Bright L.

2011-01-01

The electrical power system of a spacecraft plays a very critical role for space mission success. Such a modern power system may contain numerous hybrid DC/DC converters both inside the power system electronics (PSE) units and onboard most of the flight electronics modules. One of the faulty conditions for DC/DC converter that poses serious threats to mission safety is the random occurrence of oscillation related to inherent instability characteristics of the DC/DC converters and design deficiency of the power systems. To ensure the highest reliability of the power system, oscillations in any form shall be promptly detected during part level testing, system integration tests, flight health monitoring, and on-board fault diagnosis. The popular gain/phase margin analysis method is capable of predicting stability levels of DC/DC converters, but it is limited only to verification of designs and to part-level testing on some of the models. This method has to inject noise signals into the control loop circuitry as required, thus, interrupts the DC/DC converter's normal operation and increases risks of degrading and damaging the flight unit. A novel technique to detect oscillations at early stage for flight hybrid DC/DC converters was developed.

Powering the High-Luminosity Triplets

NASA Astrophysics Data System (ADS)

Ballarino, A.; Burnet, J. P.

The powering of the magnets in the LHC High-Luminosity Triplets requires production and transfer of more than 150 kA of DC current. High precision power converters will be adopted, and novel High Temperature Superconducting (HTS) current leads and MgB2 based transfer lines will provide the electrical link between the power converters and the magnets. This chapter gives an overview of the systems conceived in the framework of the LHC High-Luminosity upgrade for feeding the superconducting magnet circuits. The focus is on requirements, challenges and novel developments.

Effect of Solid-State Power-Converter Harmonics on Electric-Power-Supply Systems

DOT National Transportation Integrated Search

1973-03-01

The United States utility industry has not set suitable standards, other than TIF (Telephone Interference Factor), for controlling the design of solid-state wayside and on-board power-conversion equipment, to limit the harmonic currents and voltages ...

Evaluation Of Different Power Conditioning Options For Stirling Generators

NASA Astrophysics Data System (ADS)

Garrigos, A.; Blanes, J. M.; Carrasco, J. A.; Maset, E.; Montalban, G.; Ejea, J.; Ferreres, A.; Sanchis, E.

2011-10-01

Free-piston Stirling engines are an interesting alternative for electrical power systems, especially in deep space missions where photovoltaic systems are not feasible. This kind of power generators contains two main parts, the Stirling machine and the linear alternator that converts the mechanical energy from the piston movement to electrical energy. Since the generated power is in AC form, several aspects should be assessed to use such kind of generators in a spacecraft power system: AC/DC topologies, power factor correction, power regulation techniques, integration into the power system, etc. This paper details power generator operation and explores different power conversion approaches.

Fluidic-thermochromic display device

NASA Technical Reports Server (NTRS)

Grafstein, D.; Hilborn, E. H.

1968-01-01

Fluidic decoder and display device has low-power requirements for temperature control of thermochromic materials. An electro-to-fluid converter translates incoming electrical signals into pneumatics signal of sufficient power to operate the fluidic logic elements.

PV source based high voltage gain current fed converter

NASA Astrophysics Data System (ADS)

Saha, Soumya; Poddar, Sahityika; Chimonyo, Kudzai B.; Arunkumar, G.; Elangovan, D.

2017-11-01

This work involves designing and simulation of a PV source based high voltage gain, current fed converter. It deals with an isolated DC-DC converter which utilizes boost converter topology. The proposed converter is capable of high voltage gain and above all have very high efficiency levels as proved by the simulation results. The project intends to produce an output of 800 V dc from a 48 V dc input. The simulation results obtained from PSIM application interface were used to analyze the performance of the proposed converter. Transformer used in the circuit steps up the voltage as well as to provide electrical isolation between the low voltage and high voltage side. Since the converter involves high switching frequency of 100 kHz, ultrafast recovery diodes are employed in the circuitry. The major application of the project is for future modeling of solar powered electric hybrid cars.

Diesel Engine Waste Heat Recovery Utilizing Electric Turbocompound Technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hopman, Ulrich,; Kruiswyk, Richard W.

2005-07-05

Caterpillar's Technology & Solutions Division conceived, designed, built and tested an electric turbocompound system for an on-highway heavy-duty truck engine. The heart of the system is a unique turbochargerr with an electric motor/generator mounted on the shaft between turbine and compressor wheels. When the power produced by the turbocharger turbine exceeds the power of the compressor, the excess power is converted to electrical power by the generator on the turbo shaft; that power is then used to help turn the crankshaft via an electric motor mounted in the engine flywheel housing. The net result is an improvement in engine fuelmore » economy. The electric turbocompound system provides added control flexibility because it is capable of varying the amount of power extracted from the exhaust gases, thus allowing for control of engine boost. The system configuration and design, turbocharger features, control system development, and test results are presented.« less

An ocean kinetic energy converter for low-power applications using piezoelectric disk elements

NASA Astrophysics Data System (ADS)

Viñolo, C.; Toma, D.; Mànuel, A.; del Rio, J.

2013-09-01

The main problem facing long-term electronic system deployments in the sea, is to find a feasible way to supply them with the power they require. Harvesting mechanical energy from the ocean wave oscillations and converting it into electrical energy, provides an alternative method for creating self-contained power sources. However, the very low and varying frequency of ocean waves, which generally varies from 0.1 Hz to 2 Hz, presents a hurdle which has to be overcome if this mechanical energy is to be harvested. In this paper, a new sea wave kinetic energy converter is described using low-cost disk piezoelectric elements, which has no dependence on their excitement frequency, to feed low-consumption maritime-deployed electronic devices. The operating principles of the piezoelectric device technique are presented, including analytical formulations describing the transfer of energy. Finally, a prototypical design, which generates electrical energy from the motion of a buoy, is introduced. The paper concludes with the the behavior study of the piezoelectric prototype device as a power generator.

30 CFR 1206.351 - What definitions apply to this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

... of electricity for sale or to convert geothermal energy into electrical energy for sale. Contract... energy of the geothermal resource for direct use purposes. Electrical facility means a power plant or... formations; (3) Heat or other associated energy found in geothermal formations; and (4) Any byproducts. Gross...

Voltage regulation and power losses reduction in a wind farm integrated MV distribution network

NASA Astrophysics Data System (ADS)

Fandi, Ghaeth; Igbinovia, Famous Omar; Tlusty, Josef; Mahmoud, Rateb

2018-01-01

A medium-voltage (MV) wind production system is proposed in this paper. The system applies a medium-voltage permanent magnet synchronous generator (PMSG) as well as MV interconnection and distribution networks. The simulation scheme of an existing commercial electric-power system (Case A) and a proposed wind farm with a gearless PMSG insulated gate bipolar transistor (IGBT) power electronics converter scheme (Case B) is compared. The analyses carried out in MATLAB/Simulink environment shows an enhanced voltage profile and reduced power losses, thus, efficiency in installed IGBT power electronics devices in the wind farm. The resulting wind energy transformation scheme is a simple and controllable medium voltage application since it is not restrained by the IGBT power electronics voltage source converter (VSC) arrangement. Active and reactive power control is made possible with the aid of the gearless PMSG IGBT power converters.

Electrokinetic Analysis of Energy Harvest from Natural Salt Gradients in Nanochannels.

PubMed

He, Yuhui; Huang, Zhuo; Chen, Bowei; Tsutsui, Makusu; Shui Miao, Xiang; Taniguchi, Masateru

2017-10-13

The Gibbs free energy released during the mixing of river and sea water has been illustrated as a promising source of clean and renewable energy. Reverse electrodialysis (RED) is one major strategy to gain electrical power from this natural salinity, and recently by utilizing nanochannels a novel mode of this approach has shown improved power density and energy converting efficiency. In this work, we carry out an electrokinetic analysis of the work extracted from RED in the nanochannels. First, we outline the exclusion potential effect induced by the inhomogeneous distribution of extra-counterions along the channel axis. This effect is unique in nanochannel RED and how to optimize it for energy harvesting is the central topic of this work. We then discuss two important indexes of performance, which are the output power density and the energy converting efficiency, and their dependence on the nanochannel parameters such as channel material and geometry. In order to yield maximized output electrical power, we propose a device design by stepwise usage of the saline bias, and the lengths of the nanochannels are optimized to achieve the best trade-off between the input thermal power and the energy converting efficiency.

13. EAST FACADE OF THE FREQUENCY CHANGER HOUSE. IT WAS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. EAST FACADE OF THE FREQUENCY CHANGER HOUSE. IT WAS IN THIS BUILDING THAT 60 CYCLE AC POWER WAS CONVERTED TO 25 CYCLE DC POWER FOR USE IN CHICAGO'S TRANSIT SYSTEM; THE FREQUENCY CHANGER HOUSE IS PRESENTLY USED FOR STORAGE. LOOKING WEST. - Commonwealth Electric Company, Fisk Street Electrical Generating Station, 1111 West Cermak Avenue, Chicago, Cook County, IL

Advanced medium-voltage bidirectional dc-dc conversion systems for future electric energy delivery and management systems

NASA Astrophysics Data System (ADS)

Fan, Haifeng

2011-12-01

The distributed renewable energy generation and utilization are constantly growing, and are expected to be integrated with the conventional grid. The growing pressure for innovative solutions will demand power electronics to take an even larger role in future electric energy delivery and management systems, since power electronics are required for the conversion and control of electric energy by most dispersed generation systems Furthermore, power electronics systems can provide additional intelligent energy management, grid stability and power quality capabilities. Medium-voltage isolated dc-dc converter will become one of the key interfaces for grid components with moderate power ratings. To address the demand of medium voltage (MV) and high power capability for future electric energy delivery and management systems, the power electronics community and industry have been reacting in two different ways: developing semiconductor technology or directly connecting devices in series/parallel to reach higher nominal voltages and currents while maintaining conventional converter topologies; and by developing new converter topologies with traditional semiconductor technology, known as multilevel converters or modular converters. The modular approach uses the well-known, mature, and cheaper power semiconductor devices by adopting new converter topologies. The main advantages of the modular approach include: significant improvement in reliability by introducing desired level of redundancy; standardization of components leading to reduction in manufacturing cost and time; power systems can be easily reconfigured to support varying input-output specifications; and possibly higher efficiency and power density of the overall system. Input-series output-parallel (ISOP) modular configuration is a good choice to realize MV to low voltage (LV) conversion for utility application. However, challenges still remain. First of all, for the high-frequency MV utility application, the low switching loss and conduction loss are must-haves for high efficiency, while bidirectional power flow capability is a must for power management requirement. To address the demand, the phase-shift dual-halfbridge (DHB) is proposed as the constituent module of ISOP configuration for MV application. The proposed ISOP DHB converter employs zero-voltage-switching (ZVS) technique combined with LV MOSFETs to achieve low switching and conduction losses under high frequency operation, and therefore high efficiency and high power density, and bidirectional power flow as well. Secondly, a large load range of high efficiency is desired rather than only a specific load point due to the continuous operation and large load variation range of utility application, which is of high importance because of the rising energy cost. This work proposes a novel DHB converter with an adaptive commutation inductor. By utilizing an adaptive inductor as the main energy transfer element, the output power can be controlled by not only the phase shift but also the commutation inductance, which allows the circulating energy to be optimized for different load conditions to maintain ZVS under light load conditions and minimize additional conduction losses under heavy load conditions as well. As a result, the efficiency at both light and heavy load can be significantly improved compared with the conventional DHB converter, and therefore extended high-efficiency range can be achieved. In addition, current stress of switch devices can be reduced. The theoretical analysis is presented and validated by the experimental results on a 50 kHz, 1 kW dc-dc converter module. Thirdly, input-voltage sharing and output-current sharing are critical to assure the advantages of the ISOP modular configuration. To solve this issue, an identically distributed control scheme is proposed in this work. The proposed control scheme, using only one distributed voltage loop to realize both input-voltage and output-current sharing, provides plug-and-play capability, possible high-level fault tolerance, and easy implementation. Another unique advantage of the proposed ISOP DHB converter is the power rating can be easily extended further by directly connecting multiple ISOP DHB converters in input-parallel-outparallel (IPOP) while no additional control is needed. The proposed control scheme is elaborated using the large-signal average model. Further, the stability of the control schemes is analyzed in terms of the constituent modules' topology as well as the configuration, and then an important fact that the stability of control scheme depends on not only the configuration but also the constituent module topology is first revealed in this work. Finally, the simulation and experimental results of an ISOP DHB converter consisting of three modules are presented to verify the proposed control scheme and the high frequency high efficiency operation.

Experimental study of a fuel cell power train for road transport application

NASA Astrophysics Data System (ADS)

Corbo, P.; Corcione, F. E.; Migliardini, F.; Veneri, O.

The development of fuel cell electric vehicles requires the on-board integration of fuel cell systems and electric energy storage devices, with an appropriate energy management system. The optimization of performance and efficiency needs an experimental analysis of the power train, which has to be effected in both stationary and transient conditions (including standard driving cycles). In this paper experimental results concerning the performance of a fuel cell power train are reported and discussed. In particular characterization results for a small sized fuel cell system (FCS), based on a 2.5 kW PEM stack, alone and coupled to an electric propulsion chain of 3.7 kW are presented and discussed. The control unit of the FCS allowed the main stack operative parameters (stoichiometric ratio, hydrogen and air pressure, temperature) to be varied and regulated in order to obtain optimized polarization and efficiency curves. Experimental runs effected on the power train during standard driving cycles have allowed the performance and efficiency of the individual components (fuel cell stack and auxiliaries, dc-dc converter, traction batteries, electric engine) to be evaluated, evidencing the role of output current and voltage of the dc-dc converter in directing the energy flows within the propulsion system.

Grid-independent residential power systems

NASA Astrophysics Data System (ADS)

Nelson, Robert E.

1996-02-01

A self-powered, gas-fired, warm air furnace is evaluated as a candidate for the autonomous generation of electrical power. A popular, commercial residential furnace is analyzed for electrical power requirements. Available energy conversion concepts are considered for this application, and the thermophotovoltaic (TPV) option is selected due to reliability and cost. The design and the internal components peculiar to the TPV converter will be covered. Operating results, including NOx emission, will be summarized. This work was sponsored by the Basic Research Group, Gas Research Institute, Chicago, IL.

An Overview of Stationary Fuel Cell Technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

DR Brown; R Jones

1999-03-23

Technology developments occurring in the past few years have resulted in the initial commercialization of phosphoric acid (PA) fuel cells. Ongoing research and development (R and D) promises further improvement in PA fuel cell technology, as well as the development of proton exchange membrane (PEM), molten carbonate (MC), and solid oxide (SO) fuel cell technologies. In the long run, this collection of fuel cell options will be able to serve a wide range of electric power and cogeneration applications. A fuel cell converts the chemical energy of a fuel into electrical energy without the use of a thermal cycle ormore » rotating equipment. In contrast, most electrical generating devices (e.g., steam and gas turbine cycles, reciprocating engines) first convert chemical energy into thermal energy and then mechanical energy before finally generating electricity. Like a battery, a fuel cell is an electrochemical device, but there are important differences. Batteries store chemical energy and convert it into electrical energy on demand, until the chemical energy has been depleted. Depleted secondary batteries may be recharged by applying an external power source, while depleted primary batteries must be replaced. Fuel cells, on the other hand, will operate continuously, as long as they are externally supplied with a fuel and an oxidant.« less

High efficiency GaP power conversion for Betavoltaic applications

NASA Astrophysics Data System (ADS)

Sims, Paul E.; Dinetta, Louis C.; Barnett, Allen M.

1994-09-01

AstroPower is developing a gallium phosphide (GaP) based energy converter optimized for radio luminescent light-based power supplies. A 'two-step' or 'indirect' process is used where a phosphor is excited by radioactive decay products to produce light that is then converted to electricity by a photovoltaic energy converter. This indirect conversion of beta-radiation to electrical energy can be realized by applying recent developments in tritium based radio luminescent (RL) light sources in combination with the high conversion efficiencies that can be achieved under low illumination with low leakage, gallium phosphide based devices. This tritium to light approach is inherently safer than battery designs that incorporate high activity radionuclides because the beta particles emitted by tritium are of low average energy and are easily stopped by a thin layer of glass. GaP layers were grown by liquid phase epitaxy and p/n junction devices were fabricated and characterized for low light intensity power conversion. AstroPower has demonstrated the feasibility of the GaP based energy converter with the following key results: 23.54 percent conversion efficiency under 968 muW/sq cm 440 nm blue light, 14.59 percent conversion efficiency for 2.85 muW/sq cm 440 nm blue light, and fabrication of working 5 V array. We have also determined that at least 20 muW/sq cm optical power is available for betavoltaic power systems. Successful developments of this device is an enabling technology for low volume, safe, high voltage, milliwatt power supplies with service lifetimes in excess of 12 years.

High efficiency GaP power conversion for Betavoltaic applications

NASA Technical Reports Server (NTRS)

Sims, Paul E.; Dinetta, Louis C.; Barnett, Allen M.

1994-01-01

AstroPower is developing a gallium phosphide (GaP) based energy converter optimized for radio luminescent light-based power supplies. A 'two-step' or 'indirect' process is used where a phosphor is excited by radioactive decay products to produce light that is then converted to electricity by a photovoltaic energy converter. This indirect conversion of beta-radiation to electrical energy can be realized by applying recent developments in tritium based radio luminescent (RL) light sources in combination with the high conversion efficiencies that can be achieved under low illumination with low leakage, gallium phosphide based devices. This tritium to light approach is inherently safer than battery designs that incorporate high activity radionuclides because the beta particles emitted by tritium are of low average energy and are easily stopped by a thin layer of glass. GaP layers were grown by liquid phase epitaxy and p/n junction devices were fabricated and characterized for low light intensity power conversion. AstroPower has demonstrated the feasibility of the GaP based energy converter with the following key results: 23.54 percent conversion efficiency under 968 muW/sq cm 440 nm blue light, 14.59 percent conversion efficiency for 2.85 muW/sq cm 440 nm blue light, and fabrication of working 5 V array. We have also determined that at least 20 muW/sq cm optical power is available for betavoltaic power systems. Successful developments of this device is an enabling technology for low volume, safe, high voltage, milliwatt power supplies with service lifetimes in excess of 12 years.

A modular electric power system test bed for small spacecraft

NASA Technical Reports Server (NTRS)

Button, Robert M.; Baez, Anastacio N.

1994-01-01

In the new climate of smaller, faster, and cheaper space science satellites, a new power system topology has been developed at the NASA Lewis Research Center. This new topology is based on a series connected boost converter (SCBC) and can greatly affect the size, weight, fault tolerance, and cost of any small spacecraft using photovoltaic solar arrays. The paper presents electric power system design factors and requirements as background information. The series connected boost converter topology is discussed and several advantages over existing technologies are illustrated. Besides being small, lightweight, and efficient, this topology has the added benefit of inherent fault tolerance. A positive ground power system test bed has been developed for the TROPIX spacecraft program. Performance of the SCBC in the test bed is described in detail. SCBC efficiencies of 95 percent to 98 percent have been measured. Finally, a modular, photovoltaic regulator 'kit' concept is presented. Two SCBC's are used to regulate solar array charging of batteries and to provide 'utilitytype' power to the user loads. The kit's modularity will allow a spacecraft electric power system to be built from off-the-shelf hardware; resulting in smaller, faster, and cheaper spacecraft.

Push-pull switching power amplifier

NASA Technical Reports Server (NTRS)

Cuk, Slobodan M. (Inventor)

1980-01-01

A true push-pull switching power amplifier is disclosed utilizing two dc-to-dc converters. Each converter is comprised of two inductances, one inductance in series with a DC source and the other inductor in series with the output load, and an electrical energy transferring device with storage capability, namely storage capacitance, with suitable switching means between the inductances to obtain DC level conversion, where the switching means allows bidirectional current (and power) flow, and the switching means of one dc-to-dc converter is driven by the complement of a square-wave switching signal for the other dc-to-dc converter for true push-pull operation. For reduction of current ripple, the inductances in each of the two converters may be coupled, and with proper design of the coupling, the ripple can be reduced to zero at either the input or the output, but preferably the output.

Design and power management of an offshore medium voltage DC microgrid realized through high voltage power electronics technologies and control

NASA Astrophysics Data System (ADS)

Grainger, Brandon Michael

The growth in the electric power industry's portfolio of Direct Current (DC) based generation and loads have captured the attention of many leading research institutions. Opportunities for using DC based systems have been explored in electric ship design and have been a proven, reliable solution for transmitting bulk power onshore and offshore. To integrate many of the renewable resources into our existing AC grid, a number of power conversions through power electronics are required to condition the equipment for direct connection. Within the power conversion stages, there is always a requirement to convert to or from DC. The AC microgrid is a conceptual solution proposed for integrating various types of renewable generation resources. The fundamental microgrid requirements include the capability of operating in islanding mode and/or grid connected modes. The technical challenges associated with microgrids include (1) operation modes and transitions that comply with IEEE1547 without extensive custom engineering and (2) control architecture and communication. The Medium Voltage DC (MVDC) architecture, explored by the University of Pittsburgh, can be visualized as a special type of DC microgrid. This dissertation is multi-faceted, focused on many design aspects of an offshore DC microgrid. The focal points of the discussion are focused on optimized high power, high frequency magnetic material performance in electric machines, transformers, and DC/DC power converters---all components found within offshore, power system architectures. A new controller design based upon model reference control is proposed and shown to stabilize the electric motor drives (modeled as constant power loads), which serve as the largest power consuming entities in the microgrid. The design and simulation of a state-of-the-art multilevel converter for High Voltage DC (HVDC) is discussed and a component sensitivity analysis on fault current peaks is explored. A power management routine is proposed and evaluated as the DC microgrid is disturbed through various mode transitions. Finally, two communication protocols are described for the microgrid---one to minimize communication overhead inside the microgrid and another to provide robust and scalable intra-grid communication. The work presented is supported by Asea Brown Boveri (ABB) Corporate Research Center within the Active Grid Infrastructure program, the Advanced Research Project Agency - Energy (ARPA-E) through the Solar ADEPT program, and Mitsubishi Electric Corporation (MELCO).

Experimental study of camel powered electricity generation unit

NASA Astrophysics Data System (ADS)

Jakhar, O. P.; Choudhary, Rahul Raj; Budaniya, Mukesh; Kumar, Ashish

2018-05-01

Developing nations are facing a huge gap in generation and demand of electricity across the world. In present scenario the demand of electricity is increasing day by day and the shortfall of electricity has become one of the major obstructions in the development of rural areas. There is a big gap between electricity supply and demand. In India it is very difficult that to give twenty four hours electric supply in rural areas. The traditional use of camel as draught animal, for the purpose of transport of goods and agricultural work, has been drastically reduced during last few decades, due to advancements and cheaper availability of mechanical machineries. In this research paper we experimentally studied the camel powered electricity generation system at National Research Centre on Camels (NRCC) Bikaner. Camel Energy in form of high torque low speed can be converted into low torque high speed through motion converting system i.e. gear and pulley mechanism for high RPM output. This high RPM (more than 3000) output is used for electricity generation. The electricity generated can be used directly or stored in the battery and later may be used whenever it is required either for DC light or AC light using inverter. According to experimental study a camel can comfortably generate electricity up to 1KW by rotating shaft. The complete set up for electricity generation using camel power has been designed, developed and physically commissioned at National Research Centre on Camels (NRCC) Bikaner.

Load converter interactions with the secondary system in the Space Station Freedom power management and distribution DC test bed

NASA Technical Reports Server (NTRS)

Lebron, Ramon C.

1992-01-01

The NASA LeRC in Cleveland, Ohio, is responsible for the design, development, and assembly of the Space Station Freedom (SSF) Electrical Power System (EPS). In order to identify and understand system level issues during the SSF Program design and development phases, a system Power Management and Distribution (PMAD) DC test bed was assembled. Some of the objectives of this test bed facility are the evaluation of, system efficiency, power quality, system stability, and system protection and reconfiguration schemes. In order to provide a realistic operating scenario, dc Load Converter Units are used in the PMAD dc test bed to characterize the user interface with the power system. These units are dc to dc converters that provide the final system regulation before power is delivered to the load. This final regulation is required on the actual space station because the majority of user loads will require voltage levels different from the secondary bus voltage. This paper describes the testing of load converters in an end to end system environment (from solar array to loads) where their interactions and compatibility with other system components are considered. Some of the system effects of interest that are presented include load converters transient behavior interactions with protective current limiting switchgear, load converters ripple effects, and the effects of load converter constant power behavior with protective features such as foldback.

Load converter interactions with the secondary system in the Space Station Freedom power management and distribution dc test bed

NASA Technical Reports Server (NTRS)

Lebron, Ramon C.

1992-01-01

The NASA LeRC in Cleveland, Ohio, is responsible for the design, development, and assembly of the Space Station Freedom (SSF) Electrical Power System (EPS). In order to identify and understand system level issues during the SSF program design and development phases, a system Power Management and Distribution (PMAD) dc test bed was assembled. Some of the objectives of this test bed facility are the evaluation of, system efficiency, power quality, system stability, and system protection and reconfiguration schemes. In order to provide a realistic operating scenario, dc Load Converter Units are used in the PMAD dc test bed to characterize the user interface with the power system. These units are dc to dc converters that provide the final system regulation before power is delivered to the load. This final regulation is required on the actual space station because the majority of user loads will require voltage levels different from the secondary bus voltage. This paper describes the testing of load converters in an end to end system environment (from solar array to loads) where their interactions and compatibility with other system components are considered. Some of the system effects of interest that are presented include load converters transient behavior interactions with protective current limiting switchgear, load converters ripple effects, and the effects of load converter constant power behavior with protective features such as foldback.

Compact, Low-Profile Power Converters: Highly-Laminated, High-Saturation-Flux-Density, Magnetic Cores for On-Chip Inductors in Power Converter Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2010-09-01

ADEPT Project: Georgia Tech is creating compact, low-profile power adapters and power bricks using materials and tools adapted from other industries and from grid-scale power applications. Adapters and bricks convert electrical energy into useable power for many types of electronic devices, including laptop computers and mobile phones. These converters are often called wall warts because they are big, bulky, and sometimes cover up an adjacent wall socket that could be used to power another electronic device. The magnetic components traditionally used to make adapters and bricks have reached their limits; they can't be made any smaller without sacrificing performance. Georgiamore » Tech is taking a cue from grid-scale power converters that use iron alloys as magnetic cores. These low-cost alloys can handle more power than other materials, but the iron must be stacked in insulated plates to maximize energy efficiency. In order to create compact, low-profile power adapters and bricks, these stacked iron plates must be extremely thin-only hundreds of nanometers in thickness, in fact. To make plates this thin, Georgia Tech is using manufacturing tools used in microelectromechanics and other small-scale industries.« less

Implantable power generation system utilizing muscle contractions excited by electrical stimulation.

PubMed

Sahara, Genta; Hijikata, Wataru; Tomioka, Kota; Shinshi, Tadahiko

2016-06-01

An implantable power generation system driven by muscle contractions for supplying power to active implantable medical devices, such as pacemakers and neurostimulators, is proposed. In this system, a muscle is intentionally contracted by an electrical stimulation in accordance with the demands of the active implantable medical device for electrical power. The proposed system, which comprises a small electromagnetic induction generator, electrodes with an electrical circuit for stimulation and a transmission device to convert the linear motion of the muscle contractions into rotational motion for the magneto rotor, generates electrical energy. In an ex vivo demonstration using the gastrocnemius muscle of a toad, which was 28 mm in length and weighed 1.3 g, the electrical energy generated by the prototype exceeded the energy consumed for electrical stimulation, with the net power being 111 µW. It was demonstrated that the proposed implantable power generation system has the potential to replace implantable batteries for active implantable medical devices. © IMechE 2016.

Buck-boost converter for simultaneous semi-active vibration control and energy harvesting for electromagnetic regenerative shock absorber

NASA Astrophysics Data System (ADS)

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

2014-04-01

Regenerative semi-active suspensions can capture the previously dissipated vibration energy and convert it to usable electrical energy for powering on-board electronic devices, while achieve both the better ride comfort and improved road handling performance at the same time when certain control is applied. To achieve this objective, the power electronics interface circuit connecting the energy harvester and the electrical loads, which can perform simultaneous vibration control and energy harvesting function is in need. This paper utilized a buck-boost converter for simultaneous semi-active vibration control and energy harvesting with electromagnetic regenerative shock absorber, which utilizes a rotational generator to converter the vibration energy to electricity. It has been found that when the circuit works in discontinuous current mode (DCM), the ratio between the input voltage and current is only related to the duty cycle of the switch pulse width modulation signal. Using this property, the buck-boost converter can be used to perform semi-active vibration control by controlling the load connected between the terminals of the generator in the electromagnetic shock absorber. While performing the vibration control, the circuit always draw current from the shock absorber and the suspension remain dissipative, and the shock absorber takes no additional energy to perform the vibration control. The working principle and dynamics of the circuit has been analyzed and simulations were performed to validate the concept.

Programmatic status of NASA's CSTI high capacity power Stirling space power converter program

NASA Technical Reports Server (NTRS)

Dudenhoefer, James E.

1990-01-01

An overview is presented of the NASA Lewis Research Center Free-Piston Stirling Space Power Converter Technology Development Program. This work is being conducted under NASA's Civil Space Technology Initiative (CSTI). The goal of the CSTI High Capacity Power element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space initiatives. Efforts are focused upon increasing system thermal and electric energy conversion efficiency at least fivefold over current SP-100 technology, and on achieving systems that are compatible with space nuclear reactors. The status of test activities with the Space Power Research Engine (SPRE) is discussed. Design deficiencies are gradually being corrected and the power converter is now outputting 11.5 kWe at a temperature ratio of 2 (design output is 12.5 kWe). Detail designs were completed for the 1050 K Component Test Power Converter (CTPC). The success of these and future designs is dependent upon supporting research and technology efforts including heat pipes, gas bearings, superalloy joining technologies and high efficiency alternators. An update of progress in these technologies is provided.

System using a megawatt class millimeter wave source and a high-power rectenna to beam power to a suspended platform

DOEpatents

Caplan, Malcolm; Friedman, Herbert W.

2005-07-19

A system for beaming power to a high altitude platform is based upon a high power millimeter gyrotron source, optical transmission components, and a high-power receiving antenna (i.e., a rectenna) capable of rectifying received millimeter energy and converting such energy into useable electrical power.

Application of small-signal modeling and measurement techniques to the stability analysis of an integrated switching-mode power system. [onboard Dynamics Explorer Satellite

NASA Technical Reports Server (NTRS)

Wong, R. C.; Owen, H. A., Jr.; Wilson, T. G.; Rodriguez, G. E.

1980-01-01

Small-signal modeling techniques are used in a system stability analysis of a breadboard version of a complete functional electrical power system. The system consists of a regulated switching dc-to-dc converter, a solar-cell-array simulator, a solar-array EMI filter, battery chargers and linear shunt regulators. Loss mechanisms in the converter power stage, including switching-time effects in the semiconductor elements, are incorporated into the modeling procedure to provide an accurate representation of the system without requiring frequency-domain measurements to determine the damping factor. The small-signal system model is validated by the use of special measurement techniques which are adapted to the poor signal-to-noise ratio encountered in switching-mode systems. The complete electrical power system with the solar-array EMI filter is shown to be stable over the intended range of operation.

High-Efficiency Hall Thruster Discharge Power Converter

NASA Technical Reports Server (NTRS)

Jaquish, Thomas

2015-01-01

Busek Company, Inc., is designing, building, and testing a new printed circuit board converter. The new converter consists of two series or parallel boards (slices) intended to power a high-voltage Hall accelerator (HiVHAC) thruster or other similarly sized electric propulsion devices. The converter accepts 80- to 160-V input and generates 200- to 700-V isolated output while delivering continually adjustable 300-W to 3.5-kW power. Busek built and demonstrated one board that achieved nearly 94 percent efficiency the first time it was turned on, with projected efficiency exceeding 97 percent following timing software optimization. The board has a projected specific mass of 1.2 kg/kW, achieved through high-frequency switching. In Phase II, Busek optimized to exceed 97 percent efficiency and built a second prototype in a form factor more appropriate for flight. This converter then was integrated with a set of upgraded existing boards for powering magnets and the cathode. The program culminated with integrating the entire power processing unit and testing it on a Busek thruster and on NASA's HiVHAC thruster.

Design of a quasi-flat linear permanent magnet generator for pico-scale wave energy converter in south coast of Yogyakarta, Indonesia

NASA Astrophysics Data System (ADS)

Azhari, Budi; Prawinnetou, Wassy; Hutama, Dewangga Adhyaksa

2017-03-01

Indonesia has several potential ocean energies to utilize. One of them is tidal wave energy, which the potential is about 49 GW. To convert the tidal wave energy to electricity, linear permanent magnet generator (LPMG) is considered as the best appliance. In this paper, a pico-scale tidal wave power converter was designed using quasi-flat LPMG. The generator was meant to be applied in southern coast of Yogyakarta, Indonesia and was expected to generate 1 kW output. First, a quasi-flat LPMG was designed based on the expected output power and the wave characteristic at the placement site. The design was then simulated using finite element software of FEMM. Finally, the output values were calculated and the output characteristics were analyzed. The results showed that the designed power plant was able to produce output power of 725.78 Wp for each phase, with electrical efficiency of 64.5%. The output characteristics of the LPMG: output power would increase as the average wave height or wave period increases. Besides, the efficiency would increase if the external load resistance increases. Meanwhile the output power of the generator would be maximum at load resistance equals 11 Ω.

Solar thermal power systems point-focusing distributed receiver technology project. Volume 2: Detailed report

NASA Technical Reports Server (NTRS)

1980-01-01

The accomplishments of the Point-Focusing Distributed Receiver Technology Project during fiscal year 1979 are detailed. Present studies involve designs of modular units that collect and concentrate solar energy via highly reflective, parabolic-shaped dishes. The concentrated energy is then converted to heat in a working fluid, such as hot gas. In modules designed to produce heat for industrial applications, a flexible line conveys the heated fluid from the module to a heat transfer network. In modules designed to produce electricity the fluid carries the heat directly to an engine in a power conversion unit located at the focus of the concentrator. The engine is mechanically linked to an electric generator. A Brayton-cycle engine is currently being developed as the most promising electrical energy converter to meet near-future needs.

Solar-to-vehicle (S2V) systems for powering commuters of the future

NASA Astrophysics Data System (ADS)

Birnie, Dunbar P.

Hybrid electric vehicles are growing in popularity and significance in our marketplace as gasoline prices continue to rise. Consumers are also increasingly aware of their carbon "footprint" and seek ways of lowering their carbon dioxide output. Plug-in hybrid and electric vehicles appear to be the next wave in helping transition from a gasoline-based transportation infrastructure to an electric-grid-sourced mode, though most plug-in scenarios ultimately rely on having the electric utilities converted from fossil sources to renewable generation in the long run. At present, one of the key advantages of plug-in hybrid/electric vehicles is that they can be charged at home, at night, when lower off-peak rates could apply. The present analysis considers a further advancement: the impact of daytime recharging using solar arrays located at commuters' work sites. This would convert large parking areas into solar recharge stations for commuters. The solar power would be large enough to supply many commuters' needs. The implications for electric car design in relation to commuter range are discussed in detail.

High-pressure microhydraulic actuator

DOEpatents

Mosier, Bruce P [San Francisco, CA; Crocker, Robert W [Fremont, CA; Patel, Kamlesh D [Dublin, CA

2008-06-10

Electrokinetic ("EK") pumps convert electric to mechanical work when an electric field exerts a body force on ions in the Debye layer of a fluid in a packed bed, which then viscously drags the fluid. Porous silica and polymer monoliths (2.5-mm O.D., and 6-mm to 10-mm length) having a narrow pore size distribution have been developed that are capable of large pressure gradients (250-500 psi/mm) when large electric fields (1000-1500 V/cm) are applied. Flowrates up to 200 .mu.L/min and delivery pressures up to 1200 psi have been demonstrated. Forces up to 5 lb-force at 0.5 mm/s (12 mW) have been demonstrated with a battery-powered DC-DC converter. Hydraulic power of 17 mW (900 psi@ 180 uL/min) has been demonstrated with wall-powered high voltage supplies. The force and stroke delivered by an actuator utilizing an EK pump are shown to exceed the output of solenoids, stepper motors, and DC motors of similar size, despite the low thermodynamic efficiency.

A proposed national wind power R and D program. [offshore wind power system for electric energy supplies

NASA Technical Reports Server (NTRS)

Heronemus, W.

1973-01-01

An offshore wind power system is described that consists of wind driven electrical dc generators mounted on floating towers in offshore waters. The output from the generators supplies underwater electrolyzer stations in which water is converted into hydrogen and oxygen. The hydrogen is piped to shore for conversion to electricity in fuel cell stations. It is estimated that this system can produce 159 x 10 to the ninth power kilowatt-hours per year. It is concluded that solar energy - and that includes wind energy - is the only way out of the US energy dilemma in the not too distant future.

Experimental prototype of an electric elevator

NASA Astrophysics Data System (ADS)

Gaiceanu, M.; Epure, S.; Ciuta, S.

2016-08-01

The main objective is to achieve an elevator prototype powered by a three-phase voltage system via a bidirectional static power converter ac-ac with regenerating capability. In order to diminish the power size of the electric motor up to 1/3 of rated power, the elevator contains two carriages of the same weight, one serving as the payload, and the other as counterweight. Before proper operation of the static power converter, the capacitor must be charged at rated voltage via a precharge circuit. At the moment of stabilizing the DC voltage at nominal value, the AC-AC power converter can operates in the proper limits. The functions of the control structure are: the load control task, speed and torque controls. System includes transducers for current measuring, voltage sensors and encoder. As reserve power sources the hybrid battery-photovoltaic panels are used. The control voltage is modulated by implementing four types of pulse width modulations: sinusoidal, with reduced commutation, third order harmonic insertion, and the space vector modulation. Therefore, the prototype could operates with an increased efficiency, in spite of the existing ones. The experimental results confirm the well design of the chosen solution. The control solution assures bidirectional power flow control, precharge control, and load control and it is implemented on a digital signal processor. The elevator capacity is between 300-450 kg, and it is driven by using a 1.5 kW three-phase asynchronous machine.

Modeling and analysis of solar distributed generation

NASA Astrophysics Data System (ADS)

Ortiz Rivera, Eduardo Ivan

Recent changes in the global economy are creating a big impact in our daily life. The price of oil is increasing and the number of reserves are less every day. Also, dramatic demographic changes are impacting the viability of the electric infrastructure and ultimately the economic future of the industry. These are some of the reasons that many countries are looking for alternative energy to produce electric energy. The most common form of green energy in our daily life is solar energy. To convert solar energy into electrical energy is required solar panels, dc-dc converters, power control, sensors, and inverters. In this work, a photovoltaic module, PVM, model using the electrical characteristics provided by the manufacturer data sheet is presented for power system applications. Experimental results from testing are showed, verifying the proposed PVM model. Also in this work, three maximum power point tracker, MPPT, algorithms would be presented to obtain the maximum power from a PVM. The first MPPT algorithm is a method based on the Rolle's and Lagrange's Theorems and can provide at least an approximate answer to a family of transcendental functions that cannot be solved using differential calculus. The second MPPT algorithm is based on the approximation of the proposed PVM model using fractional polynomials where the shape, boundary conditions and performance of the proposed PVM model are satisfied. The third MPPT algorithm is based in the determination of the optimal duty cycle for a dc-dc converter and the previous knowledge of the load or load matching conditions. Also, four algorithms to calculate the effective irradiance level and temperature over a photovoltaic module are presented in this work. The main reasons to develop these algorithms are for monitoring climate conditions, the elimination of temperature and solar irradiance sensors, reductions in cost for a photovoltaic inverter system, and development of new algorithms to be integrated with maximum power point tracking algorithms. Finally, several PV power applications will be presented like circuit analysis for a load connected to two different PV arrays, speed control for a do motor connected to a PVM, and a novel single phase photovoltaic inverter system using the Z-source converter.

Harvesting electrical energy from torsional thermal actuation driven by natural convection.

PubMed

Kim, Shi Hyeong; Sim, Hyeon Jun; Hyeon, Jae Sang; Suh, Dongseok; Spinks, Geoffrey M; Baughman, Ray H; Kim, Seon Jeong

2018-06-07

The development of practical, cost-effective systems for the conversion of low-grade waste heat to electrical energy is an important area of renewable energy research. We here demonstrate a thermal energy harvester that is driven by the small temperature fluctuations provided by natural convection. This harvester uses coiled yarn artificial muscles, comprising well-aligned shape memory polyurethane (SMPU) microfibers, to convert thermal energy to torsional mechanical energy, which is then electromagnetically converted to electrical energy. Temperature fluctuations in a yarn muscle, having a maximum hot-to-cold temperature difference of about 13 °C, were used to spin a magnetic rotor to a peak torsional rotation speed of 3,000 rpm. The electromagnetic energy generator converted the torsional energy to electrical energy, thereby producing an oscillating output voltage of up to 0.81 V and peak power of 4 W/kg, based on SMPU mass.

Alternative Fuels Data Center: Truck Stop Electrification for Heavy-Duty

Science.gov Websites

-board equipment so trucks can plug into electrical outlets at the truck stop. To use dual-system electrification, trucks must be equipped with AC equipment or an inverter to convert 120-volt power, electrical equipment, and hardware to plug in to the electrical outlet. Necessary electrical equipment might include an

Fuel-powered artificial muscles.

PubMed

Ebron, Von Howard; Yang, Zhiwei; Seyer, Daniel J; Kozlov, Mikhail E; Oh, Jiyoung; Xie, Hui; Razal, Joselito; Hall, Lee J; Ferraris, John P; Macdiarmid, Alan G; Baughman, Ray H

2006-03-17

Artificial muscles and electric motors found in autonomous robots and prosthetic limbs are typically battery-powered, which severely restricts the duration of their performance and can necessitate long inactivity during battery recharge. To help solve these problems, we demonstrated two types of artificial muscles that convert the chemical energy of high-energy-density fuels to mechanical energy. The first type stores electrical charge and uses changes in stored charge for mechanical actuation. In contrast with electrically powered electrochemical muscles, only half of the actuator cycle is electrochemical. The second type of fuel-powered muscle provides a demonstrated actuator stroke and power density comparable to those of natural skeletal muscle and generated stresses that are over a hundred times higher.

Harvesting electrostatic energy using super-hydrophobic surfaces

NASA Astrophysics Data System (ADS)

Pociecha, Dominik; Zylka, Pawel

2016-11-01

Almost all environments are now being extensively populated by miniaturized, nano-powered electronic sensor devices communicated together through wireless sensor networks building Internet of Things (IoT). Various energy harvesting techniques are being more and more frequently proposed for battery-less powering of such remote, unattended, implantable or wearable sensors or other low-power electronic gadgets. Energy harvesting relays on extracting energy from the ambient sources readily accessible at the sensor location and converting it into electrical power. The paper exploits possibility of generating electric energy safely accessible for nano-power electronics using tribo-electric and electrostatic induction phenomena displayed at super-hydrophobic surfaces impinged by water droplets. Mechanism of such interaction is discussed and illustrated by experimental results.

Heat operated cryogenic electrical generator

NASA Technical Reports Server (NTRS)

Wang, T. G.; Saffren, M. M.; Elleman, D. D. (Inventor)

1975-01-01

An electrical generator useful for providing electrical power in deep space, is disclosed. The electrical generator utilizes the unusual hydrodynamic property exhibited by liquid helium as it is converted to and from a superfluid state to cause opposite directions of rotary motion for a rotor cell thereof. The physical motion of the rotor cell was employed to move a magnetic field provided by a charged superconductive coil mounted on the exterior of the cell. An electrical conductor was placed in surrounding proximity to the cell to interact with the moving magnetic field provided by the superconductive coil and thereby generate electrical energy. A heat control arrangement was provided for the purpose of causing the liquid helium to be partially converted to and from a superfluid state by being cooled and heated, respectively.

Wind energy conversion system

DOEpatents

Longrigg, Paul

1987-01-01

The wind energy conversion system includes a wind machine having a propeller connected to a generator of electric power, the propeller rotating the generator in response to force of an incident wind. The generator converts the power of the wind to electric power for use by an electric load. Circuitry for varying the duty factor of the generator output power is connected between the generator and the load to thereby alter a loading of the generator and the propeller by the electric load. Wind speed is sensed electro-optically to provide data of wind speed upwind of the propeller, to thereby permit tip speed ratio circuitry to operate the power control circuitry and thereby optimize the tip speed ratio by varying the loading of the propeller. Accordingly, the efficiency of the wind energy conversion system is maximized.

Space processing applications payload equipment study. Volume 2D: SPA supplemental power and heat rejection kit

NASA Technical Reports Server (NTRS)

Hammel, R. L. (Editor); Smith, A. G. (Editor)

1974-01-01

The design and application of a supplementary power and heat rejection kit for the Spacelab are discussed. Two subsystems of electric power and thermal control were analyzed to define the requirements for the power and heat rejection kit (PHRK). Twelve exemplary experiments were defined and power timelines were developed. From these timeline, the experiment requirements for sustained power, peak power, and energy were determined. The electrical power subsystem of the PHRK will consist of two fuel cells, oxygen and hydrogen reactant tank assemblies, water storage tanks, plumbing, cabling, and inverters to convert the nominal 28 volt dc fuel cell output to ac power.

solar thermal power systems advanced solar thermal technology project, advanced subsystems development

NASA Technical Reports Server (NTRS)

1979-01-01

The preliminary design for a prototype small (20 kWe) solar thermal electric generating unit was completed, consisting of several subsystems. The concentrator and the receiver collect solar energy and a thermal buffer storage with a transport system is used to provide a partially smoothed heat input to the Stirling engine. A fossil-fuel combustor is included in the receiver designs to permit operation with partial or no solar insolation (hybrid). The engine converts the heat input into mechanical action that powers a generator. To obtain electric power on a large scale, multiple solar modules will be required to operate in parallel. The small solar electric power plant used as a baseline design will provide electricity at remote sites and small communities.

A geothermal AMTEC system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schuller, M.J.; LeMire, R.A.; Horner-Richardson, K.

1995-12-31

The Phillips Laboratory Power and Thermal Management Division (PL/VTP), with the support of ORION International Technologies, is investigating new methods of advanced thermal to electric power conversion for space and terrestrial applications. The alkali metal thermal-to-electric converter (AMTEC), manufactured primarily by Advanced Modular Power Systems (AMPS) of Ann Arbor, MI, has reached a level of technological maturity which would allow its use in a constant, unattended thermal source, such as a geothermal field. Approximately 95,000 square miles in the western United States has hot dry rock with thermal gradients of 60 C/km and higher. Several places in the United Statesmore » and the world have thermal gradients of 500 C/km. Such heat sources represent an excellent thermal source for a system of modular power units using AMTEC devices to convert the heat to electricity. AMTEC cells using sodium as a working fluid require heat input at temperatures between 500 and 1,000 C to generate power. The present state of the art is capable of 15% efficiency with 800 C heat input and has demonstrated 18% efficiency for single cells. This paper discusses the basics of AMTEC operation, current drilling technology as a cost driver, design of modular AMTEC power units, heat rejection technologies, materials considerations, and estimates of power production from a geothermal AMTEC concept.« less

Space Shuttle Upgrades Advanced Hydraulic Power System

NASA Technical Reports Server (NTRS)

2004-01-01

Three Auxiliary Power Units (APU) on the Space Shuttle Orbiter each provide 145 hp shaft power to a hydraulic pump which outputs 3000 psi hydraulic fluid to 41 hydraulic actuators. A hydrazine fuel powered APU utilized throughout the Shuttle program has undergone many improvements, but concerns remain with flight safety, operational cost, critical failure modes, and hydrazine related hazards. The advanced hydraulic power system (AHPS), also known as the electric APU, is being evaluated as an upgrade to replace the hydrazine APU. The AHPS replaces the high-speed turbine and hydrazine fuel supply system with a battery power supply and electric motor/pump that converts 300 volt electrical power to 3000 psi hydraulic power. AHPS upgrade benefits include elimination of toxic hydrazine propellant to improve flight safety, reduction in hazardous ground processing operations, and improved reliability. Development of this upgrade provides many interesting challenges and includes development of four hardware elements that comprise the AHPS system: Battery - The battery provides a high voltage supply of power using lithium ion cells. This is a large battery that must provide 28 kilowatt hours of energy over 99 minutes of operation at 300 volts with a peak power of 130 kilowatts for three seconds. High Voltage Power Distribution and Control (PD&C) - The PD&C distributes electric power from the battery to the EHDU. This 300 volt system includes wiring and components necessary to distribute power and provide fault current protection. Electro-Hydraulic Drive Unit (EHDU) - The EHDU converts electric input power to hydraulic output power. The EHDU must provide over 90 kilowatts of stable, output hydraulic power at 3000 psi with high efficiency and rapid response time. Cooling System - The cooling system provides thermal control of the Orbiter hydraulic fluid and EHDU electronic components. Symposium presentation will provide an overview of the AHPS upgrade, descriptions of the four hardware elements, and a summary of development results to date.

An isolated bridgeless AC-DC PFC converter using a LC resonant voltage doubler rectifier

NASA Astrophysics Data System (ADS)

Lee, Sin-woo; Do, Hyun-Lark

2016-12-01

This paper proposed an isolated bridgeless AC-DC power factor correction (PFC) converter using a LC resonant voltage doubler rectifier. The proposed converter is based on isolated conventional single-ended primary inductance converter (SEPIC) PFC converter. The conduction loss of rectification is reduced than a conventional one because the proposed converter is designed to eliminate a full-bridge rectifier at an input stage. Moreover, for zero-current switching (ZCS) operation and low voltage stresses of output diodes, the secondary of the proposed converter is designed as voltage doubler with a LC resonant tank. Additionally, an input-output electrical isolation is provided for safety standard. In conclusion, high power factor is achieved and efficiency is improved. The operational principles, steady-state analysis and design equations of the proposed converter are described in detail. Experimental results from a 60 W prototype at a constant switching frequency 100 kHz are presented to verify the performance of the proposed converter.

Two new families of high-gain dc-dc power electronic converters for dc-microgrids

NASA Astrophysics Data System (ADS)

Prabhala, Venkata Anand Kishore

Distributing the electric power in dc form is an appealing solution in many applications such as telecommunications, data centers, commercial buildings, and microgrids. A high gain dc-dc power electronic converter can be used to individually link low-voltage elements such as solar panels, fuel cells, and batteries to the dc voltage bus which is usually 400 volts. This way, it is not required to put such elements in a series string to build up their voltages. Consequently, each element can function at it optimal operating point regardless of the other elements in the system. In this dissertation, first a comparative study of dc microgrid architectures and their advantages over their ac counterparts is presented. Voltage level selection of dc distribution systems is discussed from the cost, reliability, efficiency, and safety standpoints. Next, a new family of non-isolated high-voltage-gain dc-dc power electronic converters with unidirectional power flow is introduced. This family of converters benefits from a low voltage stress across its switches. The proposed topologies are versatile as they can be utilized as single-input or double-input power converters. In either case, they draw continuous currents from their sources. Lastly, a bidirectional high-voltage-gain dc-dc power electronic converter is proposed. This converter is comprised of a bidirectional boost converter which feeds a switched-capacitor architecture. The switched-capacitor stage suggested here has several advantages over the existing approaches. For example, it benefits from a higher voltage gain while it uses less number of capacitors. The proposed converters are highly efficient and modular. The operating modes, dc voltage gain, and design procedure for each converter are discussed in details. Hardware prototypes have been developed in the lab. The results obtained from the hardware agree with those of the simulation models.

Design study for a gound microwave power transmission system for use with a high-altitude powered platform

NASA Technical Reports Server (NTRS)

Brown, W. C.

1983-01-01

The conceptual design of a ground-based microwave power transmission system is described. This system is intended to supply electrical power via an air link to a high-altitude (21 km) powered platform. The platform must be equipped with the required instrumentation (RECTENNA) to convert the RF energy to dc power.

Method of electric powertrain matching for battery-powered electric cars

NASA Astrophysics Data System (ADS)

Ning, Guobao; Xiong, Lu; Zhang, Lijun; Yu, Zhuoping

2013-05-01

The current match method of electric powertrain still makes use of longitudinal dynamics, which can't realize maximum capacity for on-board energy storage unit and can't reach lowest equivalent fuel consumption as well. Another match method focuses on improving available space considering reasonable layout of vehicle to enlarge rated energy capacity for on-board energy storage unit, which can keep the longitudinal dynamics performance almost unchanged but can't reach lowest fuel consumption. Considering the characteristics of driving motor, method of electric powertrain matching utilizing conventional longitudinal dynamics for driving system and cut-and-try method for energy storage system is proposed for passenger cars converted from traditional ones. Through combining the utilization of vehicle space which contributes to the on-board energy amount, vehicle longitudinal performance requirements, vehicle equivalent fuel consumption level, passive safety requirements and maximum driving range requirement together, a comprehensive optimal match method of electric powertrain for battery-powered electric vehicle is raised. In simulation, the vehicle model and match method is built in Matlab/simulink, and the Environmental Protection Agency (EPA) Urban Dynamometer Driving Schedule (UDDS) is chosen as a test condition. The simulation results show that 2.62% of regenerative energy and 2% of energy storage efficiency are increased relative to the traditional method. The research conclusions provide theoretical and practical solutions for electric powertrain matching for modern battery-powered electric vehicles especially for those converted from traditional ones, and further enhance dynamics of electric vehicles.

Photovoltaics: A Solar Technology for Powering Tomorrow.

ERIC Educational Resources Information Center

Flavin, Christopher

1983-01-01

Photovoltaics, the technology that converts sunlight directly into electricity, may soon be a reliable power source for the world's poor. The one major challenge is cost reduction. Many topics are discussed, including solar powering the Third World, designing the solar building, investing in the sun, and the future of photovoltaics. (NW)

Design and Testing of a Breadboard Electrical Power Control Unit for the Fluid Combustion Facility Experiment

NASA Technical Reports Server (NTRS)

Kimnach, Greg L.; Lebron, Ramon C.

1999-01-01

The Fluid Combustion Facility (FCF) Project and the Power Technology Division at the NASA Glenn Research Center (GRC) at Lewis Field in Cleveland, OH along with the Sundstrand Corporation in Rockford, IL are jointly developing an Electrical Power Converter Unit (EPCU) for the Fluid Combustion Facility to be flown on the International Space Station (ISS). The FCF facility experiment contains three racks: A core rack, a combustion rack, and a fluids rack. The EPCU will be used as the power interface to the ISS 120V(sub dc) power distribution system by each FCF experiment rack which requires 28V(sub dc). The EPCU is a modular design which contains three 120V(sub dc)-to-28V(sub dc) full-bridge, power converters rated at 1 kW(sub e) each bus transferring input relays and solid-state, current-limiting input switches, 48 current-limiting, solid-state, output switches; and control and telemetry hardware. The EPCU has all controls required to autonomously share load demand between the power feeds and--if absolutely necessary--shed loads. The EPCU, which maximizes the usage of allocated ISS power and minimizes loss of power to loads, can be paralleled with other EPCUs. This paper overviews the electrical design and operating characteristics of the EPCU and presents test data from the breadboard design.

Electrical Power Conversion of a River and Tidal Power Generator: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muljadi, Eduard; Gevorgian, Vahan; Wright, Alan

As renewable generation has become less expensive during recent decades, and it becomes more accepted by the global population, the focus on renewable generation has expanded to include new types with promising future applications, such as river and tidal generation. Although the utilization of power electronics and electric machines in industry is phenomenal, the emphasis on system design is different for various sectors of industry. In precision control, robotics, and weaponry, the design emphasis is on accuracy and reliability with less concern for the cost of the final product. In energy generation, the cost of energy is the prime concern;more » thus, capital expenditures (CAPEX) and operations and maintenance expenditures (OPEX) are the major design objectives. This paper describes the electrical power conversion aspects of river and tidal generation. Although modern power converter control is available to control the generation side, the design was chosen on the bases of minimizing the CAPEX and OPEX; thus, the architecture is simple and modular for ease of replacement and maintenance. The power conversion is simplified by considering a simple diode bridge and a DC-DC power converter to take advantage of abundant and low-cost photovoltaic inverters that have well-proven grid integration characteristics (i.e., the capability to produce energy with good power quality and control real power and voltage on the grid side).« less

Electrical Power Conversion of River and Tidal Power Generator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muljadi, Eduard; Gevorgian, Vahan; Wright, Alan

As renewable generation has become less expensive during recent decades, and it becomes more accepted by the global population, the focus on renewable generation has expanded to include new types with promising future applications, such as river and tidal generation. Although the utilization of power electronics and electric machines in industry is phenomenal, the emphasis on system design is different for various sectors of industry. In precision control, robotics, and weaponry, the design emphasis is on accuracy and reliability with less concern for the cost of the final product. In energy generation, the cost of energy is the prime concern;more » thus, capital expenditures (CAPEX) and operations and maintenance expenditures (OPEX) are the major design objectives. This paper describes the electrical power conversion aspects of river and tidal generation. Although modern power converter control is available to control the generation side, the design was chosen on the bases of minimizing the CAPEX and OPEX; thus, the architecture is simple and modular for ease of replacement and maintenance. The power conversion is simplified by considering a simple diode bridge and a DC-DC power converter to take advantage of abundant and low-cost photovoltaic inverters that have well-proven grid integration characteristics (i.e., the capability to produce energy with good power quality and control real power and voltage on the grid side).« less

Laser power conversion system analysis, volume 2

NASA Technical Reports Server (NTRS)

Jones, W. S.; Morgan, L. L.; Forsyth, J. B.; Skratt, J. P.

1979-01-01

The orbit-to-ground laser power conversion system analysis investigated the feasibility and cost effectiveness of converting solar energy into laser energy in space, and transmitting the laser energy to earth for conversion to electrical energy. The analysis included space laser systems with electrical outputs on the ground ranging from 100 to 10,000 MW. The space laser power system was shown to be feasible and a viable alternate to the microwave solar power satellite. The narrow laser beam provides many options and alternatives not attainable with a microwave beam.

A Survey of Power Electronics Applications in Aerospace Technologies

NASA Technical Reports Server (NTRS)

Kankam, M. David; Elbuluk, Malik E.

2001-01-01

The insertion of power electronics in aerospace technologies is becoming widespread. The application of semiconductor devices and electronic converters, as summarized in this paper, includes the International Space Station, satellite power system, and motor drives in 'more electric' technology applied to aircraft, starter/generators and reusable launch vehicles. Flywheels, servo systems embodying electromechanical actuation, and spacecraft on-board electric propulsion are discussed. Continued inroad by power electronics depends on resolving incompatibility of using variable frequency for 400 Hz-operated aircraft equipment. Dual-use electronic modules should reduce system development cost.

Unlocking Electric Power in the Oceans.

ERIC Educational Resources Information Center

Hurwood, David L.

1985-01-01

Cruising or stationary ocean thermal plants could convert the vast heat energy of the ocean into electricity for islands and underdeveloped countries. This approach to energy conservation is described with suggestions for design and outputs of plants. A model project operating in Hawaii is noted. (DH)

Space Station Freedom secondary power wiring requirements

NASA Technical Reports Server (NTRS)

Sawyer, C. R.

1994-01-01

Secondary power is produced by DDCU's (direct current to direct current converter units) and routed to and through secondary power distribution assemblies (SPDA's) to loads or tertiary distribution assemblies. This presentation outlines requirements of Space Station Freedom (SSF) EEE (electrical, electronic, and electromechanical) parts wire and the approved electrical wire and cable. The SSF PDRD (Program Definition and Requirements Document) language problems and resolution are reviewed. The cable routing to and from the SPDA's is presented as diagrams and the wire recommendations and characteristics are given.

Energy harvesting from cerebrospinal fluid pressure fluctuations for self-powered neural implants.

PubMed

Beker, Levent; Benet, Arnau; Meybodi, Ali Tayebi; Eovino, Ben; Pisano, Albert P; Lin, Liwei

2017-06-01

In this paper, a novel method to generate electrical energy by converting available mechanical energy from pressure fluctuations of the cerebrospinal fluid within lateral ventricles of the brain is presented. The generated electrical power can be supplied to the neural implants and either eliminate their battery need or extend the battery lifespan. A diaphragm type harvester comprised of piezoelectric material is utilized to convert the pressure fluctuations to electrical energy. The pressure fluctuations cause the diaphragm to bend, and the strained piezoelectric materials generate electricity. In the framework of this study, an energy harvesting structure having a diameter of 2.5 mm was designed and fabricated using microfabrication techniques. A 1:1 model of lateral ventricles was 3D-printed from raw MRI images to characterize the harvester. Experimental results show that a maximum power of 0.62 nW can be generated from the harvester under similar physical conditions in lateral ventricles which corresponds to energy density of 12.6 nW/cm 2 . Considering the available area within the lateral ventricles and the size of harvesters that can be built using microfabrication techniques it is possible to amplify to power up to 26 nW. As such, the idea of generating electrical energy by making use of pressure fluctuations within brain is demonstrated in this work via the 3D-printed model system.

A High-Efficiency Wind Energy Harvester for Autonomous Embedded Systems

PubMed Central

Brunelli, Davide

2016-01-01

Energy harvesting is currently a hot research topic, mainly as a consequence of the increasing attractiveness of computing and sensing solutions based on small, low-power distributed embedded systems. Harvesting may enable systems to operate in a deploy-and-forget mode, particularly when power grid is absent and the use of rechargeable batteries is unattractive due to their limited lifetime and maintenance requirements. This paper focuses on wind flow as an energy source feasible to meet the energy needs of a small autonomous embedded system. In particular the contribution is on the electrical converter and system integration. We characterize the micro-wind turbine, we define a detailed model of its behaviour, and then we focused on a highly efficient circuit to convert wind energy into electrical energy. The optimized design features an overall volume smaller than 64 cm3. The core of the harvester is a high efficiency buck-boost converter which performs an optimal power point tracking. Experimental results show that the wind generator boosts efficiency over a wide range of operating conditions. PMID:26959018

A High-Efficiency Wind Energy Harvester for Autonomous Embedded Systems.

PubMed

Brunelli, Davide

2016-03-04

Energy harvesting is currently a hot research topic, mainly as a consequence of the increasing attractiveness of computing and sensing solutions based on small, low-power distributed embedded systems. Harvesting may enable systems to operate in a deploy-and-forget mode, particularly when power grid is absent and the use of rechargeable batteries is unattractive due to their limited lifetime and maintenance requirements. This paper focuses on wind flow as an energy source feasible to meet the energy needs of a small autonomous embedded system. In particular the contribution is on the electrical converter and system integration. We characterize the micro-wind turbine, we define a detailed model of its behaviour, and then we focused on a highly efficient circuit to convert wind energy into electrical energy. The optimized design features an overall volume smaller than 64 cm³. The core of the harvester is a high efficiency buck-boost converter which performs an optimal power point tracking. Experimental results show that the wind generator boosts efficiency over a wide range of operating conditions.

Hybrid thermionic-photovoltaic converter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Datas, A.

2016-04-04

A conceptual device for the direct conversion of heat into electricity is presented. This concept hybridizes thermionic (TI) and thermophotovoltaic (TPV) energy conversion in a single thermionic-photovoltaic (TIPV) solid-state device. This device transforms into electricity both the electron and photon fluxes emitted by an incandescent surface. This letter presents an idealized analysis of this device in order to determine its theoretical potential. According to this analysis, the key advantage of this converter, with respect to either TPV or TI, is the higher power density in an extended temperature range. For low temperatures, TIPV performs like TPV due to the negligiblemore » electron flux. On the contrary, for high temperatures, TIPV performs like TI due to the great enhancement of the electron flux, which overshadows the photon flux contribution. At the intermediate temperatures, ∼1650 K in the case of this particular study, I show that the power density potential of TIPV converter is twice as great as that of TPV and TI. The greatest impact concerns applications in which the temperature varies in a relatively wide range, for which averaged power density enhancement above 500% is attainable.« less

Wireless acoustic-electric feed-through for power and signal transmission

NASA Technical Reports Server (NTRS)

Doty, Benjamin (Inventor); Badescu, Mircea (Inventor); Sherrit, Stewart (Inventor); Bao, Xiaoqi (Inventor); Bar-Cohen, Yoseph (Inventor); Chang, Zensheu (Inventor)

2011-01-01

An embodiment provides electrical energy from a source on one side of a medium to a load on the other side of the medium, the embodiment including a first piezoelectric to generate acoustic energy in response to electrical energy from the source, and a second piezoelectric to convert the received acoustic energy to electrical energy used by the load. Other embodiments are described and claimed.

Efficient Design in a DC to DC Converter Unit

NASA Technical Reports Server (NTRS)

Bruemmer, Joel E.; Williams, Fitch R.; Schmitz, Gregory V.

2002-01-01

Space Flight hardware requires high power conversion efficiencies due to limited power availability and weight penalties of cooling systems. The International Space Station (ISS) Electric Power System (EPS) DC-DC Converter Unit (DDCU) power converter is no exception. This paper explores the design methods and tradeoffs that were utilized to accomplish high efficiency in the DDCU. An isolating DC to DC converter was selected for the ISS power system because of requirements for separate primary and secondary grounds and for a well-regulated secondary output voltage derived from a widely varying input voltage. A flyback-current-fed push-pull topology or improved Weinberg circuit was chosen for this converter because of its potential for high efficiency and reliability. To enhance efficiency, a non-dissipative snubber circuit for the very-low-Rds-on Field Effect Transistors (FETs) was utilized, redistributing the energy that could be wasted during the switching cycle of the power FETs. A unique, low-impedance connection system was utilized to improve contact resistance over a bolted connection. For improved consistency in performance and to lower internal wiring inductance and losses a planar bus system is employed. All of these choices contributed to the design of a 6.25 KW regulated dc to dc converter that is 95 percent efficient. The methodology used in the design of this DC to DC Converter Unit may be directly applicable to other systems that require a conservative approach to efficient power conversion and distribution.

Potential Operating Orbits for Fission Electric Propulsion Systems Driven by the SAFE-400

NASA Technical Reports Server (NTRS)

Houts, Mike; Kos, Larry; Poston, David; Rodgers, Stephen L. (Technical Monitor)

2002-01-01

Safety must be ensured during all phases of space fission system design, development, fabrication, launch, operation, and shutdown. One potential space fission system application is fission electric propulsion (FEP), in which fission energy is converted into electricity and used to power high efficiency (Isp greater than 3000s) electric thrusters. For these types of systems it is important to determine which operational scenarios ensure safety while allowing maximum mission performance and flexibility. Space fission systems are essentially nonradioactive at launch, prior to extended operation at high power. Once high power operation begins, system radiological inventory steadily increases as fission products build up. For a given fission product isotope, the maximum radiological inventory is typically achieved once the system has operated for a length of time equivalent to several half-lives. After that time, the isotope decays at the same rate it is produced, and no further inventory builds in. For an FEP mission beginning in Earth orbit, altitude and orbital lifetime increase as the propulsion system operates. Two simultaneous effects of fission propulsion system operation are thus (1) increasing fission product inventory and (2) increasing orbital lifetime. Phrased differently, as fission products build up, more time is required for the fission products to naturally convert back into non-radioactive isotopes. Simultaneously, as fission products build up, orbital lifetime increases, providing more time for the fission products to naturally convert back into non-radioactive isotopes. Operational constraints required to ensure safety can thus be quantified.

Potential operating orbits for fission electric propulsion systems driven by the SAFE-400

NASA Astrophysics Data System (ADS)

Houts, Mike; Kos, Larry; Poston, David

2002-01-01

Safety must be ensured during all phases of space fission system design, development, fabrication, launch, operation, and shutdown. One potential space fission system application is fission electric propulsion (FEP), in which fission energy is converted into electricity and used to power high efficiency (Isp>3000s) electric thrusters. For these types of systems it is important to determine which operational scenarios ensure safety while allowing maximum mission performance and flexibility. Space fission systems are essentially non-radioactive at launch, prior to extended operation at high power. Once high power operation begins, system radiological inventory steadily increases as fission products build up. For a given fission product isotope, the maximum radiological inventory is typically achieved once the system has operated for a length of time equivalent to several half-lives. After that time, the isotope decays at the same rate it is produced, and no further inventory builds in. For an FEP mission beginning in Earth orbit, altitude and orbital lifetime increase as the propulsion system operates. Two simultaneous effects of fission propulsion system operation are thus (1) increasing fission product inventory and (2) increasing orbital lifetime. Phrased differently, as fission products build up, more time is required for the fission products to naturally convert back into non-radioactive isotopes. Simultaneously, as fission products build up, orbital lifetime increases, providing more time for the fission products to naturally convert back into non-radioactive isotopes. Operational constraints required to ensure safety can thus be quantified. .

Overview of condition monitoring and operation control of electric power conversion systems in direct-drive wind turbines under faults

NASA Astrophysics Data System (ADS)

Huang, Shoudao; Wu, Xuan; Liu, Xiao; Gao, Jian; He, Yunze

2017-09-01

Electric power conversion system (EPCS), which consists of a generator and power converter, is one of the most important subsystems in a direct-drive wind turbine (DD-WT). However, this component accounts for the most failures (approximately 60% of the total number) in the entire DD-WT system according to statistical data. To improve the reliability of EPCSs and reduce the operation and maintenance cost of DD-WTs, numerous researchers have studied condition monitoring (CM) and fault diagnostics (FD). Numerous CM and FD techniques, which have respective advantages and disadvantages, have emerged. This paper provides an overview of the CM, FD, and operation control of EPCSs in DD-WTs under faults. After introducing the functional principle and structure of EPCS, this survey discusses the common failures in wind generators and power converters; briefly reviewed CM and FD methods and operation control of these generators and power converters under faults; and discussed the grid voltage faults related to EPCSs in DD-WTs. These theories and their related technical concepts are systematically discussed. Finally, predicted development trends are presented. The paper provides a valuable reference for developing service quality evaluation methods and fault operation control systems to achieve high-performance and high-intelligence DD-WTs.

Cryo-delivery Systems for the Co-transmission of Chemical and Electrical Power

NASA Astrophysics Data System (ADS)

Grant, Paul M.

2006-04-01

We present a novel concept for the simultaneous transport of chemical power in the form of natural gas or hydrogen in a cryogenic state along with the simultaneous transmission of electrical power over via superconductivity. This concept could impact future efforts to tap and deliver methane from distant geographic resources over conventional pipelines with part of the chemical potential energy converted directly to electricity at the wellhead and the remaining gas cooled cryogenically to increase volumetric density and provide the necessary support of a superconducting cable housed within the same packaging. As the fossil reserve becomes depleted, nuclear power plants would be constructed at the former remote wellhead sites to co-generate electricity and cryocooled hydrogen, the latter replacing natural gas and also serving to operate the already installed superconducting electrical service line.

Direct Energy Conversion Literature Abstracts

DTIC Science & Technology

1962-12-01

1961. are reviewed. Various types of solar power systems are discussed and compar- " Methods are discussed for providing ed with respect to weight...electron gas to and relate to thermoelectric methods ; convert heat to electrical energy with no thermionic, photovoltaic and electro- moving mechanical...Europ.Mach.Rev. 11:20-25,1961. appears most practical source. Direct methods of generating electrical 2853 energy without the use of fossil fuels are Power

Computational modeling of Radioisotope Thermoelectric Generators (RTG) for interplanetary and deep space travel

NASA Astrophysics Data System (ADS)

Nejat, Cyrus; Nejat, Narsis; Nejat, Najmeh

2014-06-01

This research project is part of Narsis Nejat Master of Science thesis project that it is done at Shiraz University. The goals of this research are to make a computer model to evaluate the thermal power, electrical power, amount of emitted/absorbed dose, and amount of emitted/absorbed dose rate for static Radioisotope Thermoelectric Generators (RTG)s that is include a comprehensive study of the types of RTG systems and in particular RTG’s fuel resulting from both natural and artificial isotopes, calculation of the permissible dose radioisotope selected from the above, and conceptual design modeling and comparison between several NASA made RTGs with the project computer model pointing out the strong and weakness points for using this model in nuclear industries for simulation. The heat is being converted to electricity by two major methods in RTGs: static conversion and dynamic conversion. The model that is created for this project is for RTGs that heat is being converted to electricity statically. The model approximates good results as being compared with SNAP-3, SNAP-19, MHW, and GPHS RTGs in terms of electrical power, efficiency, specific power, and types of the mission and amount of fuel mass that is required to accomplish the mission.

Prototype Combined Heater/Thermoelectric Power Generator for Remote Applications

NASA Astrophysics Data System (ADS)

Champier, D.; Favarel, C.; Bédécarrats, J. P.; Kousksou, T.; Rozis, J. F.

2013-07-01

This study presents a prototype thermoelectric generator (TEG) developed for remote applications in villages that are not connected to the electrical power grid. For ecological and economic reasons, there is growing interest in harvesting waste heat from biomass stoves to produce some electricity. Because regular maintenance is not required, TEGs are an attractive choice for small-scale power generation in inaccessible areas. The prototype developed in our laboratory is especially designed to be implemented in stoves that are also used for domestic hot water heating. The aim of this system is to provide a few watts to householders, so they have the ability to charge cellular phones and radios, and to get some light at night. A complete prototype TEG using commercial (bismuth telluride) thermoelectric modules has been built, including system integration with an electric DC/DC converter. The DC/DC converter has a maximum power point tracker (MPPT) driven by an MC9SO8 microcontroller, which optimizes the electrical energy stored in a valve-regulated lead-acid battery. Physical models were used to study the behavior of the thermoelectric system and to optimize the performance of the MPPT. Experiments using a hot gas generator to simulate the exhaust of the combustion chamber of a stove are used to evaluate the system. Additionally, potential uses of such generators are presented.

Large autonomous spacecraft electrical power system (LASEPS)

NASA Technical Reports Server (NTRS)

Dugal-Whitehead, Norma R.; Johnson, Yvette B.

1992-01-01

NASA - Marshall Space Flight Center is creating a large high voltage electrical power system testbed called LASEPS. This testbed is being developed to simulate an end-to-end power system from power generation and source to loads. When the system is completed it will have several power configurations, which will include several battery configurations. These configurations are: two 120 V batteries, one or two 150 V batteries, and one 250 to 270 V battery. This breadboard encompasses varying levels of autonomy from remote power converters to conventional software control to expert system control of the power system elements. In this paper, the construction and provisions of this breadboard are discussed.

Baseline tests of the Volkswagen transporter electric delivery van

NASA Technical Reports Server (NTRS)

Soltis, R. F.; Mcbrien, E. F.; Bozek, J. M.; Gourash, F.

1978-01-01

The Volkswagen Transporter, an electric delivery van, was tested as part of an Energy Research and Development Administration (ERDA) project to characterize the state of the art of electric vehicles. The Volkswagen Transporter is a standard Volkswagen van that has been converted to an electric vehicle. It is powered by a 144-volt traction battery. A direct current (dc) chopper controller, actuated by a conventional accelerator pedal, regulates the voltage or power applied to the 16-kilowatt (21-hp) motor. The braking system uses conventional hydraulic braking in combination with an electric regenerative braking system. The Volkswagen vehicle performance test results are presented.

Experimental investigations, modeling, and analyses of high-temperature devices for space applications: Part 1. Final report, June 1996--December 1998

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tournier, J.; El-Genk, M.S.; Huang, L.

1999-01-01

The Institute of Space and Nuclear Power Studies at the University of New Mexico has developed a computer simulation of cylindrical geometry alkali metal thermal-to-electric converter cells using a standard Fortran 77 computer code. The objective and use of this code was to compare the experimental measurements with computer simulations, upgrade the model as appropriate, and conduct investigations of various methods to improve the design and performance of the devices for improved efficiency, durability, and longer operational lifetime. The Institute of Space and Nuclear Power Studies participated in vacuum testing of PX series alkali metal thermal-to-electric converter cells and developedmore » the alkali metal thermal-to-electric converter Performance Evaluation and Analysis Model. This computer model consisted of a sodium pressure loss model, a cell electrochemical and electric model, and a radiation/conduction heat transfer model. The code closely predicted the operation and performance of a wide variety of PX series cells which led to suggestions for improvements to both lifetime and performance. The code provides valuable insight into the operation of the cell, predicts parameters of components within the cell, and is a useful tool for predicting both the transient and steady state performance of systems of cells.« less

Experimental investigations, modeling, and analyses of high-temperature devices for space applications: Part 2. Final report, June 1996--December 1998

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tournier, J.; El-Genk, M.S.; Huang, L.

1999-01-01

The Institute of Space and Nuclear Power Studies at the University of New Mexico has developed a computer simulation of cylindrical geometry alkali metal thermal-to-electric converter cells using a standard Fortran 77 computer code. The objective and use of this code was to compare the experimental measurements with computer simulations, upgrade the model as appropriate, and conduct investigations of various methods to improve the design and performance of the devices for improved efficiency, durability, and longer operational lifetime. The Institute of Space and Nuclear Power Studies participated in vacuum testing of PX series alkali metal thermal-to-electric converter cells and developedmore » the alkali metal thermal-to-electric converter Performance Evaluation and Analysis Model. This computer model consisted of a sodium pressure loss model, a cell electrochemical and electric model, and a radiation/conduction heat transfer model. The code closely predicted the operation and performance of a wide variety of PX series cells which led to suggestions for improvements to both lifetime and performance. The code provides valuable insight into the operation of the cell, predicts parameters of components within the cell, and is a useful tool for predicting both the transient and steady state performance of systems of cells.« less

Complex Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cooper, Valentino

2014-04-17

Valentino Cooper uses some of the world's most powerful computing to understand how materials work at subatomic levels, studying breakthroughs such as piezoelectrics, which convert mechanical stress to electrical energy.

Complex Materials

ScienceCinema

Cooper, Valentino

2018-05-16

Valentino Cooper uses some of the world's most powerful computing to understand how materials work at subatomic levels, studying breakthroughs such as piezoelectrics, which convert mechanical stress to electrical energy.

Development and performance of pulse-width-modulated static inverter and converter modules

NASA Technical Reports Server (NTRS)

Pittman, P. F.; Gourash, F.; Birchenough, A. G.; Pittman, P. F.; Ravas, R. J.; Hall, W. G.

1971-01-01

Pulse-width-modulated inverter and converter modules are being developed for modular aerospace electrical power systems. The modules, rate 2.5 kilowatts per module and 10-minute - 150-percent overload, operate from 56 volts dc. The converter module provides two output voltages: a nominal link voltage of 200 volts dc when used with the inverter, and 150 volts dc to a load bus when used separately. The inverter module output is 400-hertz, sinusoidal, three-phase, 120/208 volts. Tests of breadboard models with standard parts and integrated circuits show rated power efficiencies of 71.4 and 85.1 percent and voltage regulation of 5 and 3.1 percent for inverter and converter modules, respectively. Sine-wave output distortion is 0.74 percent.

A New Integrated Onboard Charger and Accessory Power Converter for Plug-in Electric Vehicles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Su, Gui-Jia; Tang, Lixin

2014-01-01

In this paper, a new approach is presented for integrating the function of onboard battery charging into the traction drive system and accessory dc-dc converter of a plug-in electric vehicle (PEV). The idea is to utilize the segmented traction drive system of a PEV as the frond converter of the charging circuit and the transformer and high voltage converter of the 14 V accessory dc-dc converter to form a galvanically isolated onboard charger. Moreover, a control method is presented for suppressing the battery current ripple component of twice the grid frequency with the reduced dc bus capacitor in the segmentedmore » inverter. The resultant integrated charger has lower cost, weight, and volume than a standalone charger due to a substantially reduced component count. The proposed integrated charger topology was verified by modeling and experimental results on a 5.8 kW charger prototype.« less

Cascaded Quadruple Active Bridge Structures for Multilevel DC to Three-Phase AC Conversion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Brian B; Achanta, Prasanta K; Maksimovic, Dragan

This paper introduces a multilevel architecture comprised of interconnected dc to three-phase ac converter units. To enable series connected operation, each converter unit contains a quadruple active bridge (QAB) converter that provides isolation between the dc side and each of the three ac sides. Since each converter unit transfers dc-side power as constant balanced three-phase power on the ac side, this implies instantaneous input-output power balance and allows elimination of bulk capacitive energy storage. In addition to minimizing required capacitance, the proposed approach simultaneously enables simplified dc-link controllers amenable to decentralized implementation, supports bidirectional power transfer, and exhibits a modularmore » structure to enhance scalability. Isolation provided by the QAB allows a wide range of electrical configurations among multiple units in various dc-ac, ac-dc or ac-ac applications. In this paper, the focus is on series connections on the ac side to emphasize multilevel operation, and the approach is experimentally validated in a dc-ac system containing two cascaded converter units.« less

Piezoelectric devices for generating low power

NASA Astrophysics Data System (ADS)

Chilibon, Irinela

2016-12-01

This paper reviews concepts and applications in low-power electronics and energy harvesting technologies. Various piezoelectric materials and devices for small power generators useful in renewable electricity are presented. The vibrating piezoelectric device differs from the typical electrical power source in that it has capacitive rather than inductive source impedance, and may be driven by mechanical vibrations of varying amplitude. In general, vibration energy could be converted into electrical energy using one of three techniques: electrostatic charge, magnetic fields and piezoelectric. A low power piezoelectric generator, having a PZT element was realised in order to supply small electronic elements, such as optoelectronic small devices, LEDs, electronic watches, small sensors, interferometry with lasers or Micro-electro-mechanical System (MEMS) array with multi-cantilevers.

Power conditioning techniques

NASA Technical Reports Server (NTRS)

Baumann, E. D.

1989-01-01

The technological developments required to reduce the electrical power system component weights from the state-of-the-art 2.0 kg/kW to the range of 0.1 to 0.2 kg/kW are discussed. Power level requirements and their trends in aerospace applications are identified and presented. The projected weight and launch costs for a 1MW power converter built using state-of-the-art technology are established to illustrate the need for reliable, ultralightweight advanced power components. The key factors affecting converter weight are given and some of the tradeoffs between component ratings and circuit topology are identified. The weight and launch costs for a 1MW converter using 0.1 kg/kW technology are presented. Finally, the objectives and goals of the Multi-Megawatt Program at the NASA Lewis Research Center, which is funded by the SDIO through the Air Force, are given.

Progress update of NASA's free-piston Stirling space power converter technology project

NASA Technical Reports Server (NTRS)

Dudenhoefer, James E.; Winter, Jerry M.; Alger, Donald

1992-01-01

A progress update is presented of the NASA LeRC Free-Piston Stirling Space Power Converter Technology Project. This work is being conducted under NASA's Civil Space Technology Initiative (CSTI). The goal of the CSTI High Capacity Power Element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space initiatives. Efforts are focused upon increasing system power output and system thermal and electric energy conversion efficiency at least five fold over current SP-100 technology, and on achieving systems that are compatible with space nuclear reactors. This paper will discuss progress toward 1050 K Stirling Space Power Converters. Fabrication is nearly completed for the 1050 K Component Test Power Converter (CTPC); results of motoring tests of the cold end (525 K), are presented. The success of these and future designs is dependent upon supporting research and technology efforts including heat pipes, bearings, superalloy joining technologies, high efficiency alternators, life and reliability testing, and predictive methodologies. This paper will compare progress in significant areas of component development from the start of the program with the Space Power Development Engine (SPDE) to the present work on CTPC.

Thermal power systems, point-focusing distributed receiver technology project. Volume 2: Detailed report

NASA Technical Reports Server (NTRS)

Lucas, J.

1979-01-01

Thermal or electrical power from the sun's radiated energy through Point-Focusing Distributed Receiver technology is the goal of this Project. The energy thus produced must be economically competitive with other sources. The Project supports the industrial development of technology and hardware for extracting energy from solar power to achieve the stated goal. Present studies are working to concentrate the solar energy through mirrors or lenses, to a working fluid or gas, and through a power converter change to an energy source useful to man. Rankine-cycle and Brayton-cycle engines are currently being developed as the most promising energy converters for our near future needs.

Digital control of a direct current converter for a hybrid vehicle

NASA Astrophysics Data System (ADS)

Hernandez, Juan Manuel

The nonlinear feedback loops permitting the large signal control of pulse width modulators in direct current converters are discussed. A digital feedback loop on a converter controlling the coupling of a direct current machine is described. It is used in the propulsion of a hybrid vehicle (thermal-electric) with regenerative braking. The protection of the power switches is also studied. An active protection of the MOST bipolar transistor association is proposed.

Variable-speed wind power system with improved energy capture via multilevel conversion

DOEpatents

Erickson, Robert W.; Al-Naseem, Osama A.; Fingersh, Lee Jay

2005-05-31

A system and method for efficiently capturing electrical energy from a variable-speed generator are disclosed. The system includes a matrix converter using full-bridge, multilevel switch cells, in which semiconductor devices are clamped to a known constant DC voltage of a capacitor. The multilevel matrix converter is capable of generating multilevel voltage wave waveform of arbitrary magnitude and frequencies. The matrix converter can be controlled by using space vector modulation.

Thermacoustic piezoelectric generator

DOEpatents

Keolian; Robert M. , Wuthrich; John W. , Bastyr; Kevin J.

2010-08-10

An electroactive transducer converts between acoustical power and electrical power. The transducer includes a diaphragm and a perimeter member. The perimeter member includes at least one electroactive element and is mechanically coupled to the perimeter of the diaphragm such that displacement of the diaphragm stresses the electroactive element.

Preliminary environmental assessment for the satellite power system (SPS). Revision 1. Volume 1. Executive summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1980-01-01

A preliminary assessment of the environmental impacts of the proposed satellite power system (SPS) is summarized here. In this system, satellites would collect solar energy in space, convert it to microwaves, and transmit the microwaves to receiving antennas (rectennas) on earth. At the rectennas, the microwaves would be converted to electricity. The assessment considers microwave and nonmicrowave effects on the terrestrial environment and human health, atmospheric effects, and disruption of communications and other electromagnetic systems.

Electronics for Deep Space Cryogenic Applications

NASA Technical Reports Server (NTRS)

Patterson, R. L.; Hammond, A.; Dickman, J. E.; Gerber, S. S.; Elbuluk, M. E.; Overton, E.

2002-01-01

Deep space probes and planetary exploration missions require electrical power management and control systems that are capable of efficient and reliable operation in very cold temperature environments. Typically, in deep space probes, heating elements are used to keep the spacecraft electronics near room temperature. The utilization of power electronics designed for and operated at low temperature will contribute to increasing efficiency and improving reliability of space power systems. At NASA Glenn Research Center, commercial-off-the-shelf devices as well as developed components are being investigated for potential use at low temperatures. These devices include semiconductor switching devices, magnetics, and capacitors. Integrated circuits such as digital-to-analog and analog-to-digital converters, DC/DC converters, operational amplifiers, and oscillators are also being evaluated. In this paper, results will be presented for selected analog-to-digital converters, oscillators, DC/DC converters, and pulse width modulation (PWM) controllers.

Cryogenic Cooling for Myriad Applications-A STAR Is Born

NASA Technical Reports Server (NTRS)

2006-01-01

Cryogenics, the science of generating extremely low temperatures, has wide applicability throughout NASA. The Agency employs cryogenics for rocket propulsion, high-pressure gas supply, breathable air in space, life support equipment, electricity, water, food preservation and packaging, medicine, imaging devices, and electronics. Cryogenic liquid oxygen and liquid hydrogen systems are also replacing solid rocket motor propulsion systems in most of the proposed launch systems, a reversion to old-style liquid propellants. In the late 1980s, NASA wanted a compact linear alternator/motor with reduced size and mass, as well as high efficiency, that had unlimited service life for use in a thermally driven power generator for space power applications. Prior development work with free-piston Stirling converters (a Stirling engine integrated with a linear actuator that produces electrical power output) had shown the promise of that technology for high-power space applications. A dual use for terrestrial applications exists for compact Stirling converters for onsite combined heat and power units. The Stirling cycle is also usable in reverse as a refrigeration cycle suitable for cryogenic cooling, so this Stirling converter work promised double benefits as well as dual uses. The uses for cryogenic coolers within NASA abound; commercial applications are similarly wide-ranging, from cooling liquid oxygen and nitrogen, to cryobiology and bio-storage, cryosurgery, instrument and detector cooling, semiconductor manufacturing, and support service for cooled superconducting power systems.

Comprehensive Evaluation of Power Supplies at Cryogenic Temperatures for Deep Space Applications

NASA Technical Reports Server (NTRS)

Patterson, Richard L.; Gerber, Scott; Hammoud, Ahmad; Elbuluk, Malik E.; Lyons, Valerie (Technical Monitor)

2002-01-01

The operation of power electronic systems at cryogenic temperatures is anticipated in many future space missions such as planetary exploration and deep space probes. In addition to surviving the space hostile environments, electronics capable of low temperature operation would contribute to improving circuit performance, increasing system efficiency, and reducing development and launch costs. DC/DC converters are widely used in space power systems in the areas of power management, conditioning, and control. As part of the on-going Low Temperature Electronics Program at NASA, several commercial-off-the-shelf (COTS) DC/DC converters, with specifications that might fit the requirements of specific future space missions have been selected for investigation at cryogenic temperatures. The converters have been characterized in terms of their performance as a function of temperature in the range of 20 C to - 180 C. These converters ranged in electrical power from 8 W to 13 W, input voltage from 9 V to 72 V and an output voltage of 3.3 V. The experimental set-up and procedures along with the results obtained on the converters' steady state and dynamic characteristics are presented and discussed.

Distributed photovoltaic architecture powering a DC bus: Impact of duty cycle and load variations on the efficiency of the generator

NASA Astrophysics Data System (ADS)

Allouache, Hadj; Zegaoui, Abdallah; Boutoubat, Mohamed; Bokhtache, Aicha Aissa; Kessaissia, Fatma Zohra; Charles, Jean-Pierre; Aillerie, Michel

2018-05-01

This paper focuses on a photovoltaic generator feeding a load via a boost converter in a distributed PV architecture. The principal target is the evaluation of the efficiency of a distributed photovoltaic architecture powering a direct current (DC) PV bus. This task is achieved by outlining an original way for tracking the Maximum Power Point (MPP) taking into account load variations and duty cycle on the electrical quantities of the boost converter and on the PV generator output apparent impedance. Thereafter, in a given sized PV system, we analyze the influence of the load variations on the behavior of the boost converter and we deduce the limits imposed by the load on the DC PV bus. The simultaneous influences of 1- the variation of the duty cycle of the boost converter and 2- the load power on the parameters of the various components of the photovoltaic chain and on the boost performances are clearly presented as deduced by simulation.

NASA Lewis H2-O2 MHD program

NASA Technical Reports Server (NTRS)

Smith, M.; Nichols, L. D.; Seikel, G. R.

1974-01-01

Performance and power costs of H2-O2 combustion powered steam-MHD central power systems are estimated. Hydrogen gas is assumed to be transmitted by pipe from a remote coal gasifier into the city and converted to electricity in a steam MHD plant having an integral gaseous oxygen plant. These steam MHD systems appear to offer an attractive alternative to both in-city clean fueled conventional steam power plants and to remote coal fired power plants with underground electric transmission into the city. Status and plans are outlined for an experimental evaluation of H2-O2 combustion-driven MHD power generators at NASA Lewis Research Center.

A radioluminescent nuclear battery using volumetric configuration: 63Ni solution/ZnS:Cu,Al/InGaP.

PubMed

Russo, Johnny; Litz, Marc; Ray, William; Smith, Brenda; Moyers, Richard

2017-12-01

Energy dense power sources are critical to the development of compact, remote sensors for terrestrial and space applications. Nuclear batteries using β - -emitting radioisotopes possess energy densities 1000 times greater than chemical batteries. Their power generation is a function of β - flux saturation point relative to the planar (2D) configuration, β - range, and semiconductor converter. An approach to increase power density in a beta-photovoltaic (β-PV) nuclear battery is described. By using volumetric (3D) configuration, the radioisotope, nickel-63 ( 63 Ni) in a chloride solution was integrated in a phosphor film (ZnS:Cu,Al) where the β - energy is converted into optical energy. The optical energy was converted to electrical energy via an indium gallium phosphate (InGaP) photovoltaic (PV) cell, which was optimized for low light illumination and closely matched to radioluminescence (RL) spectrum. With 15mCi of 63 Ni activity, the 3D configuration energy values surpassed 2D configuration results. The highest total power conversion efficiency (η t ) of 3D configuration was 0.289% at 200µm compared 0.0638% for 2D configuration at 50µm. The highest electrical power and η t for the 3D configuration were 3.35 nW e /cm 2 at an activity of 30mCi and 0.289% at an activity of 15mCi, respectively. By using 3D configuration, the interaction space between the radioisotope source and scintillation material increased, allowing for significant electrical energy output, relative to the 2D configuration. These initial results represent a first step to increase nuclear battery power density from microwatts to milliwatts per 1000cm 3 with the implementation of higher energy β - sources. Published by Elsevier Ltd.

Microcombustor-thermoelectric power generator for 10-50 watt applications

NASA Astrophysics Data System (ADS)

Marshall, Daniel S.; Cho, Steve T.

2010-04-01

Fuel-based portable power systems, including combustion and fuel cell systems, take advantage of the 80x higher energy density of fuel over lithium battery technologies and offer the potential for much higher energy density power sources - especially for long-duration applications, such as unattended sensors. Miniaturization of fuel-based systems poses significant challenges, including processing of fuel in small channels, catalyst poisoning, and coke and soot formation. Recent advances in micro-miniature combustors in the 200Watt thermal range have enabled the development of small power sources that use the chemical energy of heavy fuel to drive thermal-to-electric converters for portable applications. CUBE Technology has developed compact Micro-Furnace combustors that efficiently deliver high-quality heat to optimized thermal-to-electric power converters, such as advanced thermoelectric power modules and Stirling motors, for portable power generation at the 10-50Watt scale. Key innovations include a compact gas-gas recuperator, innovative heavy fuel processing, coke- & soot-free operation, and combustor optimization for low balance-of-plant power use while operating at full throttle. This combustor enables the development of robust, high energy density, miniature power sources for portable applications.

Lightweight Damage Tolerant Radiators for In-Space Nuclear Electric Power and Propulsion

NASA Technical Reports Server (NTRS)

Craven, Paul; SanSoucie, Michael P.; Tomboulian, Briana; Rogers, Jan; Hyers, Robert

2014-01-01

Nuclear electric propulsion (NEP) is a promising option for high-speed in-space travel due to the high energy density of nuclear power sources and efficient electric thrusters. Advanced power conversion technologies for converting thermal energy from the reactor to electrical energy at high operating temperatures would benefit from lightweight, high temperature radiator materials. Radiator performance dictates power output for nuclear electric propulsion systems. Pitch-based carbon fiber materials have the potential to offer significant improvements in operating temperature and mass. An effort at the NASA Marshall Space Flight Center to show that woven high thermal conductivity carbon fiber mats can be used to replace standard metal and composite radiator fins to dissipate waste heat from NEP systems is ongoing. The goals of this effort are to demonstrate a proof of concept, to show that a significant improvement of specific power (power/mass) can be achieved, and to develop a thermal model with predictive capabilities. A description of this effort is presented.

Recycled Thermal Energy from High Power Light Emitting Diode Light Source.

PubMed

Ji, Jae-Hoon; Jo, GaeHun; Ha, Jae-Geun; Koo, Sang-Mo; Kamiko, Masao; Hong, JunHee; Koh, Jung-Hyuk

2018-09-01

In this research, the recycled electrical energy from wasted thermal energy in high power Light Emitting Diode (LED) system will be investigated. The luminous efficiency of lights has been improved in recent years by employing the high power LED system, therefore energy efficiency was improved compared with that of typical lighting sources. To increase energy efficiency of high power LED system further, wasted thermal energy should be re-considered. Therefore, wasted thermal energy was collected and re-used them as electrical energy. The increased electrical efficiency of high power LED devices was accomplished by considering the recycled heat energy, which is wasted thermal energy from the LED. In this work, increased electrical efficiency will be considered and investigated by employing the high power LED system, which has high thermal loss during the operating time. For this research, well designed thermoelement with heat radiation system was employed to enhance the collecting thermal energy from the LED system, and then convert it as recycled electrical energy.

Designing of new structure PID controller of boost converter for solar photovoltaic stability

NASA Astrophysics Data System (ADS)

Shabrina, Hanifati Nur; Setiawan, Eko Adhi; Sabirin, Chip Rinaldi

2017-03-01

Nowadays, the utilization of renewable energy as the source on distributed generation system is increasing. It aims to reduce reliance and power losses from utility grid and improve power stability in near loads. One example of renewable energy technology that have been highly proven on the market is solar photovoltaic (PV). This technology converts photon from sunlight into electricity. However, the fluctuation of solar radiation that often occurs become the main problem for this system. Due to this condition, the power conversion is needed to convert the change frequently in photovoltaic panel into a stable voltage to the system. Developing control of boost converter has important role to keep ability of system stabilization. A conventional PID (Proportional, Integral, Derivative) control is mostly used to achieve this goal. In this research, a design of new structure PID controller of boost converter is offered to better optimize system stability comparing to the conventional PID. Parameters obtained from this PID structure have been successfully yield a stable boost converter output at 200 V with 10% overshoot, 1.5 seconds of settling time, and 1.5% of steady-state error.

Fuel to burn : economics of converting forest thinnings to energy using BioMax in southern Oregon

Treesearch

E.M. (Ted) Bilek; Kenneth E. Skog; Jeremy Fried; Glenn Christensen

2005-01-01

Small-scale gasification plants that generate electrical energy from forest health thinnings may have the potential to deliver substantial amounts of electricity to the national grid. We evaluated the economic feasibility of two sizes of BioMax, a generator manufactured by the Community Power Corporation of Littleton, Colorado. At current avoided- cost electricity...

Fuel to burn: economics of converting forest thinnings to energy using BioMax in southern Oregon.

Treesearch

E.M. (Ted) Bilek; Kenneth E. Skog; Jeremy Fried; Glenn Christensen

2005-01-01

Small-scale gasification plants that generate electrical energy from forest health thinnings may have the potential to deliver substantial amounts of electricity to the national grid. We evaluated the economic feasibility of two sizes of BioMax, a generator manufactured by the Community Power Corporation of Littleton, Colorado. At current avoided-cost electricity...

NANOCRYSTALLINE MATERIALS FOR REMOVAL OF REDUCED SULFUR AND NITROGEN COMPOUNDS FROM FUEL GAS - PHASE II

EPA Science Inventory

Integrated gasification combined cycle (IGCC), which uses a gasilier to convert coal to fuel gas, and then uses a combined cycle power block to generate electricity. is one of the most promising technologies for generating electricity from coal in an environmentally sustainabl...

Power production and wastewater treatment simultaneously by dual-chamber microbial fuel cell technique.

PubMed

Izadi, Paniz; Rahimnejad, Mostafa; Ghoreyshi, Ali

2015-01-01

Microbial fuel cell (MFC) is a novel technology that is able to convert the chemical energy of organic and inorganic substrates to electrical energy directly. The use of fossil fuels and recent energy crisis bring increasing attention to this technology. Besides electricity generation, wastewater treatment is another application of MFCs. Sulfide is a hazardous ion that is common in wastes. In this article, dual-chamber MFC was fabricated and a mixed culture of microorganisms was used as an active biocatalyst in an anaerobic anodic chamber to convert substrate to electricity. The obtained experimental results indicate that this MFC can successfully alter sulfide to elementary sulfur and power generation. The initial concentration of sulfide in wastewater was 1.5 g L(-1) , and it was removed after 10 days of MFC operation. Maximum produced power and current density were 48.68 mW⋅m(-2) and 231.47 mA⋅m(-2) , respectively. Besides, the influences of a biocathode were investigated and accordingly the data obtained for power and current density were increased to 372.27 mW⋅m(-2) and 1,665.15 mA⋅m(-2) , respectively. © 2015 International Union of Biochemistry and Molecular Biology, Inc.

Harmonic analysis and suppression in hybrid wind & PV solar system

NASA Astrophysics Data System (ADS)

Gupta, Tripti; Namekar, Swapnil

2018-04-01

The growing demand of electricity has led to produce power through non-conventional source of energy such as solar energy, wind energy, hydro power, energy through biogas and biomass etc. Hybrid system is taken to complement the shortcoming of either sources of energy. The proposed system is grid connected hybrid wind and solar system. A 2.1 MW Doubly fed Induction Generator (DFIG) has been taken for analysis of wind farm whose rotor part is connected to two back-to-back converters. A 250 KW Photovoltaic (PV) array taken to analyze solar farm where inverter is required to convert power from DC to AC since electricity generated through solar PV is in the form of DC. Stability and reliability of the system is very important when the system is grid connected. Harmonics is the major Power quality issue which degrades the quality of power at load side. Harmonics in hybrid system arise through the use of power conversion unit. The other causes of harmonics are fluctuation in wind speed and solar irradiance. The power delivered to grid must be free from harmonics and within the limits specified by Indian grid codes. In proposed work, harmonic analysis of the hybrid system is performed in Electrical Transient Analysis program (ETAP) and single tuned harmonic filter is designed to maintain the utility grid harmonics within limits.

Fuel and power coproduction: The Liquid Phase Methanol (LPMEOH{trademark}) process demonstration at Kingsport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drown, D.P.; Brown, W.R.; Heydorn, E.C.

1997-12-31

The Liquid Phase Methanol (LPMEOH{trademark}) process uses a slurry bubble column reactor to convert syngas (primarily a mixture of carbon monoxide and hydrogen) to methanol. Because of its superior heat management, the process is able to be designed to directly handle the carbon monoxide (CO)-rich syngas characteristic of the gasification of coal, petroleum coke, residual oil, wastes, or of other hydrocarbon feedstocks. When added to an integrated gasification combined cycle (IGCC) power plant, the LPMEOH{trademark} process converts a portion of the CO-rich syngas produced by the gasifier to methanol, and the remainder of the unconverted gas is used to fuelmore » the gas turbine combined-cycle power plant. The LPMEOH{trademark} process has the flexibility to operate in a daily electricity demand load-following manner. Coproduction of power and methanol via IGCC and the LPMEOH{trademark} process provides opportunities for energy storage for electrical demand peak shaving, clean fuel for export, and/or chemical methanol sales.« less

Analysis of the geometric parameters of a solitary waves-based harvester to enhance its power output

NASA Astrophysics Data System (ADS)

Rizzo, Piervincenzo; Li, Kaiyuan

2017-07-01

We present a harvester formed by a metamaterial, an isotropic medium bonded to the metamaterial, and a wafer-type transducer glued to the medium. The harvester conveys the distributed energy of a mechanical oscillator into a focal point where this energy is converted into electricity. The metamaterial is made with an array of granular chains that host the propagation of highly nonlinear solitary waves triggered by the impact of the oscillator. At the interface between the chains and the isotropic solid, part of the acoustic energy refracts into the solid where it triggers the vibration of the solid and coalesces at a point. Here, the transducer converts the focalized stress wave and the waves generated by the reverberation with the edges into electric potential. The effects of the harvester’s geometric parameters on the amount of electrical power that can be harvested are quantified numerically. The results demonstrate that the power output of the harvester increases a few orders of magnitude when the appropriate geometric parameters are selected.

Power converter for raindrop energy harvesting application: Half-wave rectifier

NASA Astrophysics Data System (ADS)

Izrin, Izhab Muhammad; Dahari, Zuraini

2017-10-01

Harvesting raindrop energy by capturing vibration from impact of raindrop have been explored extensively. Basically, raindrop energy is generated by converting the kinetic energy of raindrop into electrical energy by using polyvinylidene fluoride (PVDF) piezoelectric. In this paper, a power converter using half-wave rectifier for raindrop harvesting energy application is designed and proposed to convert damping alternating current (AC) generated by PVDF into direct current (DC). This research presents parameter analysis of raindrop simulation used in the experiment and resistive load effect on half-wave rectifier converter. The experiment is conducted by using artificial raindrop from the height of 1.3 m to simulate the effect of different resistive load on the output of half-wave rectifier converter. The results of the 0.68 MΩ resistive load showed the best performance of the half-wave rectifier converter used in raindrop harvesting energy system, which generated 3.18 Vaverage. The peak instantaneous output generated from this experiment is 15.36 µW.

Internet of things: Sensing without power

NASA Astrophysics Data System (ADS)

Aksyuk, Vladimir A.

2017-10-01

A thermally activated micromechanical switch delivers an electrical readout signal only when irradiated by a narrowband mid-infrared light, thanks to a metamaterial element that converts light into heat.

The Analysis of a Vortex Type Magnetohydrodynamic Induction Generator

NASA Technical Reports Server (NTRS)

Lengyel, L. L.

1962-01-01

Consideration it is given to the performance to the characteristics of an AC magnetohydrodynamic power generator, A rotating magnetic field is imposed on the vortex flow of an electrically conducting fluid, which is injected tangentially into an annulus formed by two nonconducting concentric cylinders and two nonconducting end plates. A perturbation technique is used to determine the two dimensional velocity and three dimensional electromagnetic field and current distributions. Finally, the generated power, the ohmic losses, the effective power and the electrical efficiency of the converter system are calculated.

Embedded system based on PWM control of hydrogen generator with SEPIC converter

NASA Astrophysics Data System (ADS)

Fall, Cheikh; Setiawan, Eko; Habibi, Muhammad Afnan; Hodaka, Ichijo

2017-09-01

The objective of this paper is to design and to produce a micro electrical plant system based on fuel cell for teaching material-embedded systems in technical vocational training center. Based on this, the student can experience generating hydrogen by fuel cells, controlling the rate of hydrogen generation by the duty ration of single-ended primary-inductor converter(SEPIC), drawing the curve rate of hydrogen to duty ratio, generating electrical power by using hydrogen, and calculating the fuel cell efficiency when it is used as electrical energy generator. This project is of great importance insofar as students will need to acquire several skills to be able to realize it such as continuous DC DC conversion and the scientific concept behind the converter, the regulation of systems with integral proportional controllers, the installation of photovoltaic cells, the use of high-tech sensors, microcontroller programming, object-oriented programming, mastery of the fuel cell syste

Status of NASA's Stirling Space Power Converter Program

NASA Technical Reports Server (NTRS)

Dudenhoefer, James E.; Winter, Jerry M.

1991-01-01

An overview is presented of the NASA-Lewis Free-Piston Stirling Space Power Convertor Technology Program. The goal is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space initiatives. Efforts are focused upon increasing system power output and system thermal and electric energy conversion efficiency at least fivefold over current SP-100 technology, and on achieving systems that are compatible with space nuclear reactors. Stirling experience in space and progress toward 1050 and 1300 K Stirling Space Power Converters is discussed. Fabrication is nearly completed for the 1050 K Component Test Power Converters (CTPC); results of motoring tests of cold end (525 K), are presented. The success of these and future designs is dependent upon supporting research and technology efforts including heat pipes, bearings, superalloy joining technologies, high efficiency alternators, life and reliability testing and predictive methodologies. An update is provided of progress in some of these technologies leading off with a discussion of free-piston Stirling experience in space.

Control of a solar-energy-supplied electrical-power system without intermediate circuitry

NASA Astrophysics Data System (ADS)

Leistner, K.

A computer control system is developed for electric-power systems comprising solar cells and small numbers of users with individual centrally controlled converters (and storage facilities when needed). Typical system structures are reviewed; the advantages of systems without an intermediate network are outlined; the demands on a control system in such a network (optimizing generator working point and power distribution) are defined; and a flexible modular prototype system is described in detail. A charging station for lead batteries used in electric automobiles is analyzed as an example. The power requirements of the control system (30 W for generator control and 50 W for communications and distribution control) are found to limit its use to larger networks.

Solar power for the lunar night

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.

1989-01-01

Providing power over the 354 hour lunar night provides a considerable challenge to solar power concepts for a moonbase. Concepts are reviewed for providing night power for a solar powered moonbase. The categories of solutions considered are electrical storage, physical storage, transmitted power, and innovative concepts. Electrical storage is the most well-developed option. Less developed electrical storage options are capacitors and superconducting inductors. Physical storage options include storage of potential energy and storage of energy in flywheels. Thermal storage has potentially high energy/weight, but problems of conduction and radiation losses during the night need to be addressed. Transmitted power considers use of microwave or laser beams to transmit power either from orbit or directly from the Earth. Finally, innovative concepts proposed include reflecting light from orbital mirrors, locating the moonbase at a lunar pole, converting reflected Earthlight, or moving the moonbase to follow the sun.

Load insensitive electrical device. [power converters for supplying direct current at one voltage from a source at another voltage

NASA Technical Reports Server (NTRS)

Schwarz, F. C. (Inventor)

1974-01-01

A class of power converters is described for supplying direct current at one voltage from a source at another voltage. It includes a simple passive circuit arrangement of solid-state switches, inductors, and capacitors by which the output voltage of the converter tends to remain constant in spite of changes in load. The switches are sensitive to the current flowing in the circuit and are employed to permit the charging of capacitance devices in accordance with the load requirements. Because solid-state switches (such as SCR's) may be used with relatively high voltage and because of the inherent efficiency of the invention that permits relatively high switching frequencies, power supplies built in accordance with the invention, together with their associated cabling, can be substantially lighter in weight for a given output power level and efficiency of operation than systems of the prior art.

Solar Equipment

NASA Technical Reports Server (NTRS)

1983-01-01

A medical refrigeration and a water pump both powered by solar cells that convert sunlight directly into electricity are among the line of solar powered equipment manufactured by IUS (Independent Utility Systems) for use in areas where conventional power is not available. IUS benefited from NASA technology incorporated in the solar panel design and from assistance provided by Kerr Industrial Applications Center.

Blow molding electric drives of Mechanical Engineering

NASA Astrophysics Data System (ADS)

Bukhanov, S. S.; Ramazanov, M. A.; Tsirkunenko, A. T.

2018-03-01

The article considers the questions about the analysis of new possibilities, which gives the use of adjustable electric drives for blowing mechanisms of plastic production. Thus, the use of new semiconductor converters makes it possible not only to compensate the instability of the supply network by using special dynamic voltage regulators, but to improve (correct) the power factor. The calculation of economic efficiency in controlled electric drives of blowing mechanisms is given. On the basis of statistical analysis, the calculation of the reliability parameters of the regulated electric drives’ elements under consideration is given. It is shown that an increase in the reliability of adjustable electric drives is possible both due to overestimation of the electric drive’s installed power, and in simpler schemes with pulse-vector control.

Spin-Caloritronic Batteries

NASA Astrophysics Data System (ADS)

Yu, Xiao-Qin; Zhu, Zhen-Gang; Su, Gang; Jauho, A.-P.

2017-11-01

The thermoelectric performance of a topological energy converter is analyzed. The H -shaped device is based on a combination of transverse topological effects involving the spin: the inverse spin Hall effect and the spin Nernst effect. The device can convert a temperature drop in one arm into an electric power output in the other arm. Analytical expressions for the output voltage, the figure of merit (Z T ), and energy-converting efficiency are reported. We show that the output voltage and the Z T can be tuned by the geometry of the device and the physical properties of the material. Importantly, contrary to a conventional thermoelectric device, here a low electric conductivity may, in fact, enhance the Z T value, thereby opening a path to strategies in optimizing the figure of merit.

The UK wave energy resource

NASA Astrophysics Data System (ADS)

Winter, A. J. B.

1980-10-01

Previous estimates of wave energy around the United Kingdom have been made by extrapolating measurements from a few sites to the whole UK seaboard. Here directional wave spectra are used from a numerical wave model developed by the Meteorological Office to make estimates which are verified where possible by observation. It is concluded that around 30 GW of power is available for capture by wave energy converters: when estimates of converter spacing and efficiency are considered an average of about 7 GW of electrical power could be supplied. This resource estimate is smaller than previous ones, though consistent with them when factors such as the directional properties of waves and the likelihood that converters will be sited near coasts are included.

Thermoelectronic laser energy conversion for power transmission in space

NASA Technical Reports Server (NTRS)

Britt, E. J.; Yuen, C.

1977-01-01

Long distance transmission of power in space by means of laser beams is an attractive concept because of the very narrow beam divergence. Such a system requires efficient means to both generate the laser beam and to convert the light energy in the beam into useful electric output at the receiver. A plasma-type device known as a Thermo-Electronic Laser Energy Converter (TELEC) has been studied as a method of converting a 10.6 micron CO2 laser beam into electric power. In the TELEC process, electromagnetic radiation is absorbed directly in the plasma electrons producing a high electron temperature. The energetic electrons diffuse out of the plasma striking two electrodes with different areas. Since more electrons are collected by the larger electrode there is a net transport of current, and an EMF is generated in the external circuit. The smaller electrode functions as an electron emitter to provide continuity of the current. Waste heat is rejected from the large electrode. A design for a TELEC system with an input 1 MW laser beam was developed as part of the study. The calculated performance of the system showed an overall efficiency of about 42%.

Development of a dual-field heteropoplar power converter

NASA Technical Reports Server (NTRS)

Eisenhaure, D. B.; Johnson, B.; Bliamptis, T.; St. George, E.

1981-01-01

The design and testing of a 400 watt, dual phase, dual rotor, field modulated inductor alternator is described. The system is designed for use as a flywheel to ac utility line or flywheel to dc bus (electric vehicle) power converter. The machine is unique in that it uses dual rotors and separately controlled fields to produce output current and voltage which are in phase with each other. Having the voltage and current in phase allows the power electronics to be made of simple low cost components. Based on analytical predictions and experimental results, development of a complete 22 kilowatt (30 Hp) power conversion system is recommended. This system would include power electronics and controls and would replace the inductor alternator with an improved electromagnetic conversion system.

A comparison of Stirling engines for use with a 25 kW dish-electric conversion system

NASA Technical Reports Server (NTRS)

Shaltens, Richard K.

1987-01-01

Two designs for an advanced Stirling conversion system (ASCS) are described. The objective of the ASCS is to generate about 25 kW of electric power to an electric utility grid at an engine/alternator target cost of $300.00/kW at the manufacturing rate of 10,000 unit/yr. Both designs contain a free-piston Stirling engine (FPSE), a heat transport system, solar receiver, a means to generate electric power, the necessary auxiliaries, and a control system. The major differences between the two concepts are: one uses a 25 kWe single-piston FPSE which incorporates a linear alternator to directly convert the energy to electricity on the utility grid; and in the second design, electrical power is generated indirectly using a hydraulic output to a ground based hydraulic motor coupled to a rotating alternator. Diagrams of the two designs are presented.

Alternative Fuels Data Center: Yellow Cab Converts Taxis to Propane in

Science.gov Websites

electric car. College Students Engineer Efficient Vehicles in EcoCAR 2 Competition Aug. 2, 2014 Photo of a Columbus, OhioA> Yellow Cab Converts Taxis to Propane in Columbus, Ohio to someone by E-mail how Yellow Cab is overhauling their fleet in Columbus, Ohio, with propane power. For information about

From Solid Waste to Energy.

ERIC Educational Resources Information Center

Wisely, F. E.; And Others

A project designed to convert solid waste to energy is explained in this paper. In April, 1972, an investor-owned utility began to burn municipal solid waste as fuel for the direct production of electric power. This unique venture was a cooperative effort between the City of St. Louis, Missouri, and the Union Electric Company, with financial…

Multi-port power router and its impact on resilient power grid systems

NASA Astrophysics Data System (ADS)

Kado, Yuichi; Iwatsuki, Katsumi; Wada, Keiji

2016-02-01

We propose a Y-configuration power router as a unit cell to easily construct a power delivery system that can meet many types of user requirements. The Y-configuration power router controls the direction and magnitude of power flow among three ports regardless of DC and AC. We constructed a prototype three-way isolated DC/DC converter that is the core unit of the Y-configuration power router and tested the power flow control operation. Experimental results revealed that our methodology based on the governing equation was appropriate for the power flow control of the three-way DC/DC converter. In addition, the hexagonal distribution network composed of the power routers has the ability to easily interchange electric power between autonomous microgrid cells. We also explored the requirements for communication between energy routers to achieve dynamic adjustments of energy flow in a coordinated manner and its impact on resilient power grid systems.

Development of a multikilowatt ion thruster power processor

NASA Technical Reports Server (NTRS)

Schoenfeld, A. D.; Goldin, D. S.; Biess, J. J.

1972-01-01

A feasibility study was made of the application of silicon-controlled, rectifier series, resonant inverter, power conditioning technology to electric propulsion power processing operating from a 200 to 400 Vdc solar array bus. A power system block diagram was generated to meet the electrical requirements of a 20 CM hollow cathode, mercury bombardment, ion engine. The SCR series resonant inverter was developed as a primary means of power switching and conversion, and the analog signal-to-discrete-time-interval converter control system was applied to achieve good regulation. A complete breadboard was designed, fabricated, and tested with a resistive load bank, and critical power processor areas relating to efficiency, weight, and part count were identified.

Baseline tests of the EVA contractor electric passenger vehicle

NASA Technical Reports Server (NTRS)

Bozek, J. M.; Tryon, H. B.; Slavick, R. J.

1977-01-01

The EVA Contactor four door sedan, an electric passenger vehicle, was tested to characterize the state-of-the-art of electric vehicles. It is a four passenger sedan that was converted to an electric vehicle. It is powered by 16 series connected 6 volt electric vehicle batteries through a four step contactor controller actuated by a foot accelerator pedal. The controller changes the voltage applied to the separately excited DC motor. The braking system is a vacuum assisted hydraulic braking system. Regenerative braking was also provided.

A lightweight electronically commutated dc motor for electric passenger vehicles

NASA Technical Reports Server (NTRS)

Echolds, E. F.; Walla, P. S.

1982-01-01

A functional model breadboard converter and a rare-earth-cobalt, permanent magnet motor; as well as an engineering model converter and PM motor suitable for vehicle installations were developed and tested. The converter and motor achieved an 88% peak efficiency, a maximum output of 26 kW at 26,000 rpm, and a continuous rating of 15 kW. The system also generated power to the source during braking, with a demonstrated peak power available at the converter terminals of approximately 26 kW at 88% efficiency. Major conclusions include: (1) the SAE J227a(D) driving cycle efficiency for the converter/motor is 86% to 88% when energy available for recovery at the converter terminals is included; (2) the converter initial cost is approximately five times that of the permanent magnet motor, but can be reduced by means of LSI logic and integrated liquid cooled semiconductor packages; and (3) an electronically commutated motor with a liquid cooled converter will operate reliably without service or maintenance for the life of a passenger vehicle.

A lightweight electronically commutated dc motor for electric passenger vehicles

NASA Astrophysics Data System (ADS)

Echolds, E. F.; Walla, P. S.

1982-09-01

A functional model breadboard converter and a rare-earth-cobalt, permanent magnet motor; as well as an engineering model converter and PM motor suitable for vehicle installations were developed and tested. The converter and motor achieved an 88% peak efficiency, a maximum output of 26 kW at 26,000 rpm, and a continuous rating of 15 kW. The system also generated power to the source during braking, with a demonstrated peak power available at the converter terminals of approximately 26 kW at 88% efficiency. Major conclusions include: (1) the SAE J227a(D) driving cycle efficiency for the converter/motor is 86% to 88% when energy available for recovery at the converter terminals is included; (2) the converter initial cost is approximately five times that of the permanent magnet motor, but can be reduced by means of LSI logic and integrated liquid cooled semiconductor packages; and (3) an electronically commutated motor with a liquid cooled converter will operate reliably without service or maintenance for the life of a passenger vehicle.

Broadband photonic single sideband frequency up-converter based on the cross polarization modulation effect in a semiconductor optical amplifier for radio-over-fiber systems.

PubMed

Lee, Seung-Hun; Kim, Hyoung-Jun; Song, Jong-In

2014-01-13

A broadband photonic single sideband (SSB) frequency up-converter based on the cross polarization modulation (XPolM) effect in a semiconductor optical amplifier (SOA) is proposed and experimentally demonstrated. An optical radio frequency (RF) signal in the form of an optical single sideband (OSSB) is generated by the photonic SSB frequency up-converter to solve the power fading problem caused by fiber chromatic dispersion. The generated OSSB RF signal has almost identical optical carrier power and optical sideband power. This SSB frequency up-conversion scheme shows an almost flat electrical RF power response as a function of the RF frequency in a range from 31 GHz to 75 GHz after 40 km single mode fiber (SMF) transmission. The photonic SSB frequency up-conversion technique shows negligible phase noise degradation. The phase noise of the up-converted RF signal at 49 GHz for an offset of 10 kHz is -93.17 dBc/Hz. Linearity analysis shows that the photonic SSB frequency up-converter has a spurious free dynamic range (SFDR) value of 79.51 dB · Hz(2/3).

Electro-autotrophic synthesis of higher alcohols

DOEpatents

Liao, James C.; Cho, Kwang Myung

2016-11-01

The disclosure provides a process that converts CO.sub.2 to higher alcohols (e.g. isobutanol) using electricity as the energy source. This process stores electricity (e.g. from solar energy, nuclear energy, and the like) in liquid fuels that can be used as high octane number gasoline substitutes. Instead of deriving reducing power from photosynthesis, this process derives reducing power from electrically generated mediators, either H.sub.2 or formate. H.sub.2 can be derived from electrolysis of water. Formate can be generated by electrochemical reduction of CO.sub.2. After delivering the reducing power in the cell, formate becomes CO.sub.2 and recycles back. Therefore, the biological CO.sub.2 fixation process can occur in the dark.

Electro-autotrophic synthesis of higher alcohols

DOEpatents

Liao, James C.; Cho, Kwang Myung

2015-10-06

The disclosure provides a process that converts CO.sub.2 to higher alcohols (e.g. isobutanol) using electricity as the energy source. This process stores electricity (e.g. from solar energy, nuclear energy, and the like) in liquid fuels that can be used as high octane number gasoline substitutes. Instead of deriving reducing power from photosynthesis, this process derives reducing power from electrically generated mediators, either H.sub.2 or formate. H.sub.2 can be derived from electrolysis of water. Formate can be generated by electrochemical reduction of CO.sub.2. After delivering the reducing power in the cell, formate becomes CO.sub.2 and recycles back. Therefore, the biological CO.sub.2 fixation process can occur in the dark.

Microbial fuel cells: Running on gas

NASA Astrophysics Data System (ADS)

Ren, Zhiyong Jason

2017-06-01

Methane is an abundant energy source that is used for power generation in thermal power plants via combustion, but direct conversion to electricity in fuel cells remains challenging. Now, a microbial fuel cell is demonstrated to efficiently convert methane directly to current by careful selection of a consortium of microorganisms.

CONVERTING ENERGY FROM RECLAIMED HEAT: THERMAL ELECTRIC GENERATOR

EPA Science Inventory

The use of solar energy acquiring devices has been slow to gain acceptance due to their overall low power generation versus high cost of a solar system. The goal of this project is to construct a model which increases the overall power generation of a solar building system by...

OUT Success Stories: Solar Trough Power Plants

DOE R&D Accomplishments Database

Jones, J.

2000-08-01

The Solar Electric Generating System (SEGS) plants use parabolic-trough solar collectors to capture the sun's energy and convert it to heat. The SEGS plants range in capacity from 13.8 to 80 MW, and they were constructed to meet Southern California Edison Company's periods of peak power demand.

Helios Dynamics A Potential Future Power Source for the Greek Islands

DTIC Science & Technology

2007-06-01

offer an apparent understanding of the capabilities of the emerging Photovoltaic Power Converter (PVPC) technology used in panels for electricity... powering method that uses fueled generators and the alternative option is photovoltaic panels with the Atira technology embedded. This analysis is... POWER SOURCE FOR THE GREEK ISLANDS ABSTRACT The use of Alternative Renewable Energy Sources is becoming an increasing possibility to

Electrical power converter method and system employing multiple output converters

DOEpatents

Beihoff, Bruce C [Wauwatosa, WI; Radosevich, Lawrence D [Muskego, WI; Meyer, Andreas A [Richmond Heights, OH; Gollhardt, Neil [Fox Point, WI; Kannenberg, Daniel G [Waukesha, WI

2007-05-01

A support may receive one or more power electronic circuits. The support may aid in removing heat from the circuits through fluid circulating through the support. The support, in conjunction with other packaging features may form a shield from both external EMI/RFI and from interference generated by operation of the power electronic circuits. Features may be provided to permit and enhance connection of the circuitry to external circuitry, such as improved terminal configurations. Modular units may be assembled that may be coupled to electronic circuitry via plug-in arrangements or through interface with a backplane or similar mounting and interconnecting structures.

Electrical power converter method and system employing multiple-output converters

DOEpatents

Beihoff, Bruce C.; Radosevich, Lawrence D.; Meyer, Andreas A.; Gollhardt, Neil; Kannenberg, Daniel G.

2006-03-21

A support may receive one or more power electronic circuits. The support may aid in removing heat from the circuits through fluid circulating through the support. The support, in conjunction with other packaging features may form a shield from both external EMI/RFI and from interference generated by operation of the power electronic circuits. Features may be provided to permit and enhance connection of the circuitry to external circuitry, such as improved terminal configurations. Modular units may be assembled that may be coupled to electronic circuitry via plug-in arrangements or through interface with a backplane or similar mounting and interconnecting structures.

High voltage systems (tube-type microwave)/low voltage system (solid-state microwave) power distribution

NASA Technical Reports Server (NTRS)

Nussberger, A. A.; Woodcock, G. R.

1980-01-01

SPS satellite power distribution systems are described. The reference Satellite Power System (SPS) concept utilizes high-voltage klystrons to convert the onboard satellite power from dc to RF for transmission to the ground receiving station. The solar array generates this required high voltage and the power is delivered to the klystrons through a power distribution subsystem. An array switching of solar cell submodules is used to maintain bus voltage regulation. Individual klystron dc voltage conversion is performed by centralized converters. The on-board data processing system performs the necessary switching of submodules to maintain voltage regulation. Electrical power output from the solar panels is fed via switch gears into feeder buses and then into main distribution buses to the antenna. Power also is distributed to batteries so that critical functions can be provided through solar eclipses.

Connection technology of HPTO type WECs and DC nano grid in island

NASA Astrophysics Data System (ADS)

Wang, Kun-lin; Tian, Lian-fang; You, Ya-ge; Wang, Xiao-hong; Sheng, Song-wei; Zhang, Ya-qun; Ye, Yin

2016-07-01

Wave energy fluctuating a great deal endangers the security of power grid especially micro grid in island. A DC nano grid supported by batteries is proposed to smooth the output power of wave energy converters (WECs). Thus, renewable energy converters connected to DC grid is a new subject. The characteristics of WECs are very important to the connection technology of HPTO type WECs and DC nano grid. Hydraulic power take-off system (HPTO) is the core unit of the largest category of WECs, with the functions of supplying suitable damping for a WEC to absorb wave energy, and converting captured wave energy to electricity. The HPTO is divided into a hydraulic energy storage system (HESS) and a hydraulic power generation system (HPGS). A primary numerical model for the HPGS is established in this paper. Three important basic characteristics of the HPGS are deduced, which reveal how the generator load determines the HPGS rotation rate. Therefore, the connector of HPTO type WEC and DC nano grid would be an uncontrollable rectifier with high reliability, also would be a controllable power converter with high efficiency, such as interleaved boost converter-IBC. The research shows that it is very flexible to connect to DC nano grid for WECs, but bypass resistance loads are indispensable for the security of WECs.

Fossil fuel combined cycle power system

DOEpatents

Labinov, Solomon Davidovich; Armstrong, Timothy Robert; Judkins, Roddie Reagan

2006-10-10

A system for converting fuel energy to electricity includes a reformer for converting a higher molecular weight gas into at least one lower molecular weight gas, at least one turbine to produce electricity from expansion of at least one of the lower molecular weight gases, and at least one fuel cell. The system can further include at least one separation device for substantially dividing the lower molecular weight gases into at least two gas streams prior to the electrochemical oxidization step. A nuclear reactor can be used to supply at least a portion of the heat the required for the chemical conversion process.

NaK-nitrogen liquid metal MHD converter tests at 30 kw

NASA Technical Reports Server (NTRS)

Cerini, D. J.

1974-01-01

The feasibility of electrical power generation with an ambient temperature liquid-metal MHD separator cycle is demonstrated by tests in which a NaK-nitrogen LM-MHD converter was operated at nozzle inlet pressures ranging from 100 to 165 N/sq cm, NaK flow rates from 46 to 72 kg/sec, and nitrogen flow rates from 2.4 to 3.8 kg/sec. The generator was operated as an eight-phase linear induction generator, with two of the eight phases providing magnetic field compensation to minimized electrical end losses at the generator channel inlet and exit.

Development of Wave Turbine Emulator in a Laboratory Environment

NASA Astrophysics Data System (ADS)

Vinatha, U.; Vittal K, P.

2013-07-01

Wave turbine emulator (WTE) is an important equipment for developing wave energy conversion system. The emulator reflects the actual behavior of the wave turbine by reproducing the characteristics of real wave turbine without reliance on natural wave resources and actual wave turbine. It offers a controllable test environment that allows the evaluation and improvement of control schemes for electric generators. The emulator can be used for research applications to drive an electrical generator in a similar way as a practical wave turbine. This article presents the development of a WTE in a laboratory environment and studies on the behavior of electrical generator coupled to the emulator. The structure of a WTE consists of a PC where the characteristics of the turbine are implemented, ac drive to emulate the turbine rotor, feedback mechanism from the drive and power electronic equipment to control the drive. The feedback signal is acquired by the PC through an A/D converter, and the signal for driving the power electronic device comes from the PC through a D/A converter.

Application of Electric Double-layer Capacitors for Energy Storage on Electric Railway

NASA Astrophysics Data System (ADS)

Hase, Shin-Ichi; Konishi, Takeshi; Okui, Akinobu; Nakamichi, Yoshinobu; Nara, Hidetaka; Uemura, Tadashi

The methods to stabilize power sources, which are the measures against voltage drop, power loading fluctuation, regeneration power lapse and so on, have been important issues in DC feeding circuits. Therefore, an energy storage medium that uses power efficiently and reduces above-mentioned problems is much concerned about. In recent years, development of energy storage medium is remarkable for drive-power supplies of electric vehicles. A number of applications of energy storage, for instance, battery and flywheel, have been investigated so far. A large-scale electric double-layer capacitor which is rapidly charged and discharged and offers long life, maintenance-free, low pollution and high efficiency, has been developed in wide range. We have compared the ability to charge batteries and electric double-layer capacitors. Therefore, we carried out fundamental studies about electric double-layer capacitors and its control. And we produced a prototype of energy storage for the DC electric railway system that consists of electric double-layer capacitors, diode bridge rectifiers, chopper system and PWM converters. From the charge and discharge tests of the prototype, useful information was obtained. This paper describes its characteristics and experimental results of energy storage system.

Solar-Powered Refrigeration System

NASA Technical Reports Server (NTRS)

Ewert, Michael K. (Inventor); Bergeron, David J., III (Inventor)

2001-01-01

A solar powered vapor compression refrigeration system is made practicable with thermal storage and novel control techniques. In one embodiment, the refrigeration system includes a photovoltaic panel, a variable speed compressor, an insulated enclosure. and a thermal reservoir. The photovoltaic (PV) panel converts sunlight into DC (direct current) electrical power. The DC electrical power drives a compressor that circulates refrigerant through a vapor compression refrigeration loop to extract heat from the insulated enclosure. The thermal reservoir is situated inside the insulated enclosure and includes a phase change material. As heat is extracted from the insulated enclosure, the phase change material is frozen, and thereafter is able to act as a heat sink to maintain the temperature of the insulated enclosure in the absence of sunlight. The conversion of solar power into stored thermal energy is optimized by a compressor control method that effectively maximizes the compressor's usage of available energy. A capacitor is provided to smooth the power voltage and to provide additional current during compressor start-up. A controller monitors the rate of change of the smoothed power voltage to determine if the compressor is operating below or above the available power maximum, and adjusts the compressor speed accordingly. In this manner, the compressor operation is adjusted to convert substantially all available solar power into stored thermal energy.

Solar-Powered Refrigeration System

NASA Technical Reports Server (NTRS)

Ewert, Michael K. (Inventor); Bergeron, David J., III (Inventor)

2002-01-01

A solar powered vapor compression refrigeration system is made practicable with thermal storage and novel control techniques. In one embodiment, the refrigeration system includes a photovoltaic panel, a variable speed compressor, an insulated enclosure, and a thermal reservoir. The photovoltaic (PV) panel converts sunlight into DC (direct current) electrical power. The DC electrical power drives a compressor that circulates refrigerant through a vapor compression refrigeration loop to extract heat from the insulated enclosure. The thermal reservoir is situated inside the insulated enclosure and includes a phase change material. As heat is extracted from the insulated enclosure, the phase change material is frozen, and thereafter is able to act as a heat sink to maintain the temperature of the insulated enclosure in the absence of sunlight. The conversion of solar power into stored thermal energy is optimized by a compressor control method that effectively maximizes the compressor's usage of available energy. A capacitor is provided to smooth the power voltage and to provide additional current during compressor start-up. A controller monitors the rate of change of the smoothed power voltage to determine if the compressor is operating below or above the available power maximum, and adjusts the compressor speed accordingly. In this manner, the compressor operation is adjusted to convert substantially all available solar power into stored thermal energy.

Solar Powered Refrigeration System

NASA Technical Reports Server (NTRS)

Ewert, Michael K. (Inventor); Bergeron, David J., III (Inventor)

2002-01-01

A solar powered vapor compression refrigeration system is made practicable with thermal storage and novel control techniques. In one embodiment, the refrigeration system includes a photovoltaic panel, a variable speed compressor, an insulated enclosure, and a thermal reservoir. The photovoltaic (PV) panel converts sunlight into DC (direct current) electrical power. The DC electrical power drives a compressor that circulates refrigerant through a vapor compression refrigeration loop to extract heat from the insulated enclosure. The thermal reservoir is situated inside the insulated enclosure and includes a phase change material. As heat is extracted from the insulated enclosure, the phase change material is frozen, and thereafter is able to act as a heat sink to maintain the temperature of the insulated enclosure in the absence of sunlight. The conversion of solar power into stored thermal energy is optimized by a compressor control method that effectively maximizes the compressor's usage of available energy. A capacitor is provided to smooth the power voltage and to provide additional current during compressor start-up. A controller monitors the rate of change of the smoothed power voltage to determine if the compressor is operating below or above the available power maximum, and adjusts the compressor speed accordingly. In this manner, the compressor operation is adjusted to convert substantially all available solar power into stored thermal energy.

Research on spacecraft electrical power conversion

NASA Technical Reports Server (NTRS)

Wilson, T. G.

1974-01-01

The steady state characteristics and starting behavior of some widely used self-oscillating magnetically coupled square wave inverters were studied and the development of LC-tuned square wave inverters is reported. An analysis on high amplitude voltage spikes which occur in dc-to-square-wave parallel converters shows the importance of various circuit parameters for inverter design and for the suppression of spikes. A computerized simulation of an inductor energy storage dc-to-dc converter with closed loop regulators and of a preregulating current step-up converter are detailed. Work continued on the computer aided design of two-winding energy storage dc-to-dc converters.

Multi-megawatt inverter/converter technology for space power applications

NASA Technical Reports Server (NTRS)

Myers, Ira T.; Baumann, Eric D.; Kraus, Robert; Hammoud, Ahmad N.

1992-01-01

Large power conditioning mass reductions will be required to enable megawatt power systems envisioned by the Strategic Defense Initiative, the Air Force, and NASA. Phase 1 of a proposed two phase interagency program has been completed to develop an 0.1 kg/kW DC/DC converter technology base for these future space applications. Three contractors, Hughes, General Electric (GE), and Maxwell were Phase 1 contractors in a competitive program to develop a megawatt lightweight DC/DC converter. Researchers at NASA Lewis Research Center and the University of Wisconsin also investigated technology in topology and control. All three contractors, as well as the University of Wisconsin, concluded at the end of the Phase 1 study, which included some critical laboratory work, that 0.1-kg/kW megawatt DC/DC converters can be built. This is an order of magnitude lower specific weight than is presently available. A brief description of each of the concepts used to meet the ambitious goals of this program are presented.

Small solar thermal electric power plants with early commercial potential

NASA Technical Reports Server (NTRS)

Jones, H. E.; Bisantz, D. J.; Clayton, R. N.; Heiges, H. H.; Ku, A. C.

1979-01-01

Cost-effective small solar thermal electric power plants (1- to 10-MW nominal size) offer an attractive way of helping the world meet its future energy needs. The paper describes the characteristics of a conceptual near-term plant (about 1 MW) and a potential 1990 commercial version. The basic system concept is one in which steam is generated using two-axis tracking, parabolic dish, and point-focusing collectors. The steam is transported through low-loss piping to a central steam turbine generator unit where it is converted to electricity. The plants have no energy storage and their output power level varies with the solar insolation level. This system concept, which is firmly based on state-of-the-art technology, is projected to offer one of the fastest paths for U.S. commercialization of solar thermal electric power plants through moderate technology advances and mass production.

Piezoelectric diaphragm for vibration energy harvesting.

PubMed

Minazara, E; Vasic, D; Costa, F; Poulin, G

2006-12-22

This paper presents a technique of electric energy generation using a mechanically excited unimorph piezoelectric membrane transducer. The electrical characteristics of the piezoelectric power generator are investigated under dynamic conditions. The electromechanical model of the generator is presented and used to predict its electrical performances. The experiments was performed with a piezoelectric actuator (shaker) moving a macroscopic 25 mm diameter piezoelectric membrane. A power of 0.65 mW was generated at the resonance frequency (1.71 kHz) across a 5.6 kOmega optimal resistor and for a 80 N force. A special electronic circuit has been conceived in order to increase the power harvested by the piezoelectric transducer. This electrical converter applies the SSHI (synchronized switch harvesting on inductor) technique, and leads to remarkable results: under the same actuation conditions the generated power reaches 1.7 mW, which is sufficient to supply a large range of low consumption sensors.

Baseline tests of the Kordesh hybrid passenger vehicle

NASA Technical Reports Server (NTRS)

Soltis, R. F.; Bozek, J. M.; Denington, R. J.; Dustin, M. O.

1978-01-01

Performance test results are presented for a four-passenger Austin A40 sedan that was converted to a heat-engine-alternator-and battery-powered hybrid. It is propelled by a conventional, gasoline-fueled, heat-engine-driven alternator and a traction pack powering a series-wound, 10 hp direct-current electric drive motor. The 16 hp gasoline engine drives the 7 kilowatt alternator, which provides electrical power to the drive motor or to the 96 volt traction battery through a rectifier. The propulsion battery consists of eight 12 volt batteries connected in series. The electric motor is coupled to a four-speed standard transmission, which drives the rear wheels. Power to the motor is controlled by a three-step foot throttle, which actuates relays that control armature current and field excitation. Conventional hydraulic brakes are used.

MPPT Algorithm Development for Laser Powered Surveillance Camera Power Supply Unit

NASA Astrophysics Data System (ADS)

Zhang, Yungui; Dushantha Chaminda, P. R.; Zhao, Kun; Cheng, Lin; Jiang, Yi; Peng, Kai

2018-03-01

Photovoltaics (PV) cells, modules which are semiconducting materials, convert light energy into electricity. Operation of a PV cell requires 3 basic features. When the light is absorbed it generate pairs of electron holes or excitons. An external circuit carrier opposite types of electrons irrespective of the source (sunlight or LASER light). The PV arrays have photovoltaic effect and the PV cells are defined as a device which has electrical characteristics: such as current, voltage and resistance. It varies when exposed to light, that the power output is depend on direct Laser-light. In this paper Laser-light to electricity by direct conversion with the use of PV cells and its concept of Band gap Energy, Series Resistance, Conversion Efficiency and Maximum Power Point Tracking (MPPT) methods [1].

Status of a Power Processor for the Prometheus-1 Electric Propulsion System

NASA Technical Reports Server (NTRS)

Pinero, Luis R.; Hill, Gerald M.; Aulisio, Michael; Gerber, Scott; Griebeler, Elmer; Hewitt, Frank; Scina, Joseph

2006-01-01

NASA is developing technologies for nuclear electric propulsion for proposed deep space missions in support of the Exploration initiative under Project Prometheus. Electrical power produced by the combination of a fission-based power source and a Brayton power conversion and distribution system is used by a high specific impulse ion propulsion system to propel the spaceship. The ion propulsion system include the thruster, power processor and propellant feed system. A power processor technology development effort was initiated under Project Prometheus to develop high performance and lightweight power-processing technologies suitable for the application. This effort faces multiple challenges including developing radiation hardened power modules and converters with very high power capability and efficiency to minimize the impact on the power conversion and distribution system as well as the heat rejection system. This paper documents the design and test results of the first version of the beam supply, the design of a second version of the beam supply and the design and test results of the ancillary supplies.

Study of radiatively sustained cesium plasmas for solar energy conversion

NASA Technical Reports Server (NTRS)

Palmer, A. J.; Dunning, G. J.

1980-01-01

The results of a study aimed at developing a high temperature solar electric converter are reported. The converter concept is based on the use of an alkali plasma to serve as both an efficient high temperature collector of solar radiation as well as the working fluid for a high temperature working cycle. The working cycle is a simple magnetohydrodynamic (MHD) Rankine cycle employing a solid electrode Faraday MHD channel. Research milestones include the construction of a theoretical model for coupling sunlight in a cesium plasma and the experimental demonstration of cesium plasma heating with a solar simulator in excellent agreement with the theory. Analysis of a solar MHD working cycle in which excimer laser power rather than electric power is extracted is also presented. The analysis predicts a positive gain coefficient on the cesium-xenon excimer laser transition.

WindWaveFloat (WWF): Final Scientific Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alla Weinstein; Roddier, Dominique; Banister, Kevin

2012-03-30

Principle Power Inc. and National Renewable Energy Lab (NREL) have completed a contract to assess the technical and economic feasibility of integrating wave energy converters into the WindFloat, resulting in a new concept called the WindWaveFloat (WWF). The concentration of several devices on one platform could offer a potential for both economic and operational advantages. Wind and wave energy converters can share the electrical cable and power transfer equipment to transport the electricity to shore. Access to multiple generation devices could be simplified, resulting in cost saving at the operational level. Overall capital costs may also be reduced, provided thatmore » the design of the foundation can be adapted to multiple devices with minimum modifications. Finally, the WindWaveFloat confers the ability to increase energy production from individual floating support structures, potentially leading to a reduction in levelized energy costs, an increase in the overall capacity factor, and greater stability of the electrical power delivered to the grid. The research conducted under this grant investigated the integration of several wave energy device types into the WindFloat platform. Several of the resulting system designs demonstrated technical feasibility, but the size and design constraints of the wave energy converters (technical and economic) make the WindWaveFloat concept economically unfeasible at this time. Not enough additional generation could be produced to make the additional expense associated with wave energy conversion integration into the WindFloat worthwhile.« less

Design mechanic generator under speed bumper to support electricity recourse for urban traffic light

NASA Astrophysics Data System (ADS)

Sabri, M.; Lauzuardy, Jason; Syam, Bustami

2018-03-01

The electrical energy needs for the traffic lights in some cities of developing countries cannot be achieved continuously due to limited capacity and interruption of electricity distribution, the main power plant. This issues can lead to congestion at the crossroads. To overcome the problem of street chaos due to power failure, we can cultivate to provide electrical energy from other sources such as using the bumper to generate kinetic energy, which can be converted into electrical energy. This study designed a generator mechanic that will be mounted on the bumper construction to generate electricity for the purposes of traffic lights at the crossroads. The Mechanical generator is composed of springs, levers, sprockets, chains, flywheel and customize power generator. Through the rotation of the flywheel, we can earned 9 Volt DC voltage and electrical current of 5.89 Ampere. This achievement can be used to charge the accumulator which can be used to power the traffic lights, and to charge the accumulator capacity of 6 Ah, the generator works in the charging time for 1.01 hours.

The Design, Construction, and Experimental Evaluation of a Compact Thermoacoustic-Stirling Engine Generator for Use in a micro-CHP Appliance

NASA Astrophysics Data System (ADS)

Wilcox, Douglas A., Jr.

Micro combined heat and power or micro-CHP is the simultaneous generation of useful heat and electricity on a residential scale. The heat and electricity are produced at the point of use, avoiding the distribution losses associated with a centralized power plant. These appliances combine a conventional gas-fired condensing boiler with an electric power module capable of generating electricity from the heat of combustion. Currently, the leading power modules for micro-CHP appliances are free-piston Stirling engines (FPSEs) which can generate 1050 watts of electricity at a thermal-to-electric efficiency of 26%.[1] These external combustion engines have been under development for the last 25 years, with FPSE micro-CHP appliances only recently being introduced to the commercial market. Publications by developers assert unlimited service life and high efficiency, with low noise and emissions; but despite these claims, the actual reliability and cost of manufacturing has prevented their successful mass-market adoption. A Thermoacoustic-Stirling Engine Generator or TaSEG is one possible alternative to FPSE's. A TaSEG uses a thermoacoustic engine, or acoustic heat engine, which can efficiently convert high temperature heat into acoustic power while maintaining a simple design with fewer moving parts than traditional FPSE's. This simpler engine is coupled to an electrodynamic alternator capable of converting acoustic power into electricity. This thesis outlines the design, construction, and experimental evaluation of a TaSEG which is appropriate for integration with a gas burner inside of a residential micro- CHP appliance. The design methodology is discussed, focusing on how changes in the geometry affected the predicted performance. Details of its construction are given and the performance of the TaSEG is then outlined. The TaSEG can deliver 132 watts of electrical output power to an electric load with an overall measured thermal-to-electric (first law) efficiency of eta T-E=8.32%, corresponding to 14% of Carnot etac. The volumetric power density of this TaSEG is 8.9 kW/m3. While the demonstrated overall efficiency is modest (for reasons that are largely understood), this TaSEG has moved the technology away from laboratory prototypes toward a commercially viable power module having a design configuration suitable for implementation in a micro-CHP appliance. Based on the TaSEG's measured experimental performance results, recommendations for future work that might improve the overall efficiency of the TaSEG are also presented.

Concept Developed for an Implanted Stimulated Muscle-Powered Piezoelectric Generator

NASA Technical Reports Server (NTRS)

Lewandowski, Beth; Kilgore, Kevin; Ercegovic, David; Gustafson, Kenneth

2005-01-01

Implanted electronic devices are typically powered by batteries or transcutaneous power transmission. Batteries must be replaced or recharged, and transcutaneous power sources burden the patient or subject with external equipment prone to failure. A completely self-sustaining implanted power source would alleviate these limitations. Skeletal muscle provides an available autologous power source containing native chemical energy that produces power in excess of the requirements for muscle activation by motor nerve stimulation. A concept has been developed to convert stimulated skeletal muscle power into electrical energy (see the preceding illustration). We propose to connect a piezoelectric generator between a muscle tendon and bone. Electrically stimulated muscle contractions would exert force on the piezoelectric generator, charging a storage circuit that would be used to power the stimulator and other devices.

Acoustic energy harvesting using an electromechanical Helmholtz resonator.

PubMed

Liu, Fei; Phipps, Alex; Horowitz, Stephen; Ngo, Khai; Cattafesta, Louis; Nishida, Toshikazu; Sheplak, Mark

2008-04-01

This paper presents the development of an acoustic energy harvester using an electromechanical Helmholtz resonator (EMHR). The EMHR consists of an orifice, cavity, and a piezoelectric diaphragm. Acoustic energy is converted to mechanical energy when sound incident on the orifice generates an oscillatory pressure in the cavity, which in turns causes the vibration of the diaphragm. The conversion of acoustic energy to electrical energy is achieved via piezoelectric transduction in the diaphragm of the EMHR. Moreover, the diaphragm is coupled with energy reclamation circuitry to increase the efficiency of the energy conversion. Lumped element modeling of the EMHR is used to provide physical insight into the coupled energy domain dynamics governing the energy reclamation process. The feasibility of acoustic energy reclamation using an EMHR is demonstrated in a plane wave tube for two power converter topologies. The first is comprised of only a rectifier, and the second uses a rectifier connected to a flyback converter to improve load matching. Experimental results indicate that approximately 30 mW of output power is harvested for an incident sound pressure level of 160 dB with a flyback converter. Such power level is sufficient to power a variety of low power electronic devices.

Solar power satellite system definition study. Part 1 and part 2, volume 1: Executive summary

NASA Technical Reports Server (NTRS)

1977-01-01

The Solar Power Satellite principle is illustrated and it shows that in a geostationary orbit 36,000 km above the earth's equator, each SPS is in sunlight 99% of the time and in continuous line of sight contact with its ground receiving station. Electrical power produced on the satellite by photovoltaic or heat engine conversion of sunlight is then converted to radio frequency energy at high efficiency, and formed into a focused beam precisely aimed at the SP ground stations. The ground station receiving antenna reconverts the energy into electricity for distribution.

Efficient Conversion of Lignin to Electricity Using a Novel Direct Biomass Fuel Cell Mediated by Polyoxomethalates at Low Temperatures

Treesearch

Xuebing Zhao; Junyong Zhu

2016-01-01

A novel polyoxometalates (POMs) mediated direct biomass fuelcelI (DBFC) was used in this study to directly convert lignin to electricity at low temperatures with high power output and Faradaic efficiency. When phosphomolybdic acid H3PMo12O40 (PMo12) was used as the electron and...

Alternative Fuels Data Center: Electricity Research and Development

Science.gov Websites

blades of a turbine connected to an electric generator. The turbine generator set converts mechanical and solar thermal, the heat that is produced is used to create steam, which moves the blades of the turbine. In the cases of hydropower and wind power, turbine blades are moved directly by flowing water and

A cesium TELEC experiment at Lewis Research Center

NASA Technical Reports Server (NTRS)

Britt, E. J.

1979-01-01

The thermoelectronic laser energy converter (TELEC), was studied as a method of converting a 10.6 mm CO2 laser beam into electric power. The calculated characteristics of a TELEC seem to be well matched to the requirements of a spacecraft laser energy conversion system. The TELEC is a high power density plasma device which absorbs an intense laser beam by inverse bremsstrahlung with the plasma electrons. In the TELEC process, electromagnetic radiation is absorbed directly in the plasma electrons producing a high electron temperature. The energetic electrons diffuse out of the plasma striking two electrodes which are in contact with the plasma at the boundaries. These two electrodes have different areas: the larger one is designated as the collector, the smaller one is designated as the emitter. The smaller electrode functions as an electron emitter to provide continuity of the current. Waste heat is rejected from the collector electrode. An experiment was carried out with a high power laser using a cesium vapor TELEC cell with 30 cm active length. Laser supported plasma was produced in the TELEC device during a number of laser runs over a period of several days. Electric power from the TELEC was observed with currents in the range of several amperes and output potentials of less than 1 volt. The magnitudes of these electric outputs were smaller than anticipated but consistent with the power levels of the laser during this experiment.

Maximum power extraction under different vector-control schemes and grid-synchronization strategy of a wind-driven Brushless Doubly-Fed Reluctance Generator.

PubMed

Mousa, Mohamed G; Allam, S M; Rashad, Essam M

2018-01-01

This paper proposes an advanced strategy to synchronize the wind-driven Brushless Doubly-Fed Reluctance Generator (BDFRG) to the grid-side terminals. The proposed strategy depends mainly upon determining the electrical angle of the grid voltage, θ v and using the same transformation matrix of both the power winding and grid sides to ensure that the generated power-winding voltage has the same phase-sequence of the grid-side voltage. On the other hand, the paper proposes a vector-control (power-winding flux orientation) technique for maximum wind-power extraction under two schemes summarized as; unity power-factor operation and minimum converter-current. Moreover, a soft-starting method is suggested to avoid the employed converter over-current. The first control scheme is achieved by adjusting the command power-winding reactive power at zero for a unity power-factor operation. However, the second scheme depends on setting the command d-axis control-winding current at zero to maximize the ratio of the generator electromagnetic-torque per the converter current. This enables the system to get a certain command torque under minimum converter current. A sample of the obtained simulation and experimental results is presented to check the effectiveness of the proposed control strategies. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Power conversion apparatus and method

DOEpatents

Su, Gui-Jia [Knoxville, TN

2012-02-07

A power conversion apparatus includes an interfacing circuit that enables a current source inverter to operate from a voltage energy storage device (voltage source), such as a battery, ultracapacitor or fuel cell. The interfacing circuit, also referred to as a voltage-to-current converter, transforms the voltage source into a current source that feeds a DC current to a current source inverter. The voltage-to-current converter also provides means for controlling and maintaining a constant DC bus current that supplies the current source inverter. The voltage-to-current converter also enables the current source inverter to charge the voltage energy storage device, such as during dynamic braking of a hybrid electric vehicle, without the need of reversing the direction of the DC bus current.

Low-temperature operation of a Buck DC/DC converter

NASA Technical Reports Server (NTRS)

Ray, Biswajit; Gerber, Scott S.; Patterson, Richard L.; Myers, Ira T.

1995-01-01

Low-temperature (77 K) operation of a 42/28 V, 175 W, 50 kHz PWM Buck DC/DC converter designed with commercially available components is reported. Overall, the converter losses decreased at 77 K compared to room temperature operation. A full-load efficiency of 97 percent was recorded at liquid-nitrogen temperature, compared to 95.8 percent at room temperature. Power MOSFET operation improved significantly where as the output rectifier operation deteriorated at low-temperature. The performance of the output filter inductor and capacitor did not change significantly at 77 K compared to room temperature performance. It is possible to achieve high-density and high efficiency power conversion at low-temperatures due to improved electronic, electrical and thermal properties of materials.

Solar Energy Technician/Installer

ERIC Educational Resources Information Center

Moore, Pam

2007-01-01

Solar power (also known as solar energy) is solar radiation emitted from the sun. Large panels that absorb the sun's energy as the sun beats down on them gather solar power. The energy in the rays can be used for heat (solar thermal energy) or converted to electricity (photovoltaic energy). Each solar energy project, from conception to…

Method of and system for producing electrical power

DOEpatents

Carabetta, Ralph A.; Staats, Gary E.; Cutting, John C.

1993-01-01

A method and system for converting the chemical energy of methane to electrical energy. Methane is thermally decomposed to hydrogen and carbon in a decomposing unit at a temperature not less than 1200.degree. K. and at a pressure above atmospheric pressure. Carbon and substantially pure oxygen and a cesium or potassium seed material is transmitted to a combustor which is maintained at a pressure of at least 50 atmospheres to combust the carbon and oxygen and provide an ionized plasma having a temperature not less than 2900.degree. K. The ionized plasma is accelerated to a velocity not less than 1000 m/sec and transported through an MHD generator having a magnetic field in the range of from 4 to 6 Tesla to generate dc power. The ionized plasma is decelerated and passed from the MHD generator in heat exchange relationship with the methane to heat the methane for decomposition, and thereafter any cesium or potassium seed material is recovered and transported to the combustor, and the dc power from the MHD generator is converted to ac power.

Method of and system for producing electrical power

DOEpatents

Carabetta, Ralph A.; Staats, Gary E.; Cutting, John C.

1993-01-01

A method and system for converting the chemical energy of methane to electrical energy. Methane is thermally decomposed to hydrogen and carbon in a decomposing unit at a temperature not less than about 1200.degree. K. and at a pressure at least slightly above atmospheric pressure. Carbon and substantially pure oxygen and a cesium or potassium seed material is transmitted to a combustor which is maintained at a pressure of at least about 50 atmospheres to combust the carbon and oxygen and provide an ionized plasma having a temperature not less than about 2800.degree. K. The ionized plasma is accelerated to a velocity not less than about 1000 m/sec and transported through an MHD generator having a magnetic field in the range of from about 4 to about 6 Tesla to generate dc power. The ionized plasma is de-accelerated and passed from the MHD generator in heat exchange relationship with the methane to heat same for decomposition and or reaction, and thereafter any cesium or potassium seed material is recovered and transported to the combustor, and the dc power from the MHD generator is converted to ac power.

Power processing units for high power solar electric propulsion

NASA Astrophysics Data System (ADS)

Frisbee, Robert H.; Das, Radhe S.; Krauthamer, Stanley

An evaluation of high-power processing units (PPUs) for multimegawatt solar electric propulsion (SEP) vehicles using advanced ion thrusters is presented. Significant savings of scale are possible for PPUs used to supply power to ion thrusters operating at 0.1 to 1.5 MWe per thruster. The PPU specific mass is found to be strongly sensitive to variations in the ion thruster's power per thruster and moderately sensitive to variations in the thruster's screen voltage due to varying the I(sp) of the thruster. Each PPU consists of a dc-to-dc converter to increase the voltage from the 500 V dc of the photovoltaic power system to the 5 to 13 kV dc required by the ion thrusters.

The performance simulation of single cylinder electric power confined piston engine

NASA Astrophysics Data System (ADS)

Gou, Yanan

2017-04-01

A new type of power plant. i.e, Electric Power Confined Piston Engine, is invented by combining the free piston engine and the crank connecting rod mechanism of the traditional internal combustion engine. Directly using the reciprocating movement of the piston, this new engine converts the heat energy produced by fuel to electrical energy and output it. The paper expounds the working mechanism of ECPE and establishes the kinematics and dynamics equations. Furthermore, by using the analytic method, the ECPE electromagnetic force is solved at load cases. Finally, in the simulation environment of MARLAB, the universal characteristic curve is obtained in the condition of rotational speed n between 1000 r/min and 2400 r/min, throttle opening α between 30% and 100%.

Wave Power Demonstration Project at Reedsport, Oregon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mekhiche, Mike; Downie, Bruce

2013-10-21

Ocean wave power can be a significant source of large‐scale, renewable energy for the US electrical grid. The Electrical Power Research Institute (EPRI) conservatively estimated that 20% of all US electricity could be generated by wave energy. Ocean Power Technologies, Inc. (OPT), with funding from private sources and the US Navy, developed the PowerBuoy to generate renewable energy from the readily available power in ocean waves. OPT's PowerBuoy converts the energy in ocean waves to electricity using the rise and fall of waves to move the buoy up and down (mechanical stroking) which drives an electric generator. This electricity ismore » then conditioned and transmitted ashore as high‐voltage power via underwater cable. OPT's wave power generation system includes sophisticated techniques to automatically tune the system for efficient conversion of random wave energy into low cost green electricity, for disconnecting the system in large waves for hardware safety and protection, and for automatically restoring operation when wave conditions normalize. As the first utility scale wave power project in the US, the Wave Power Demonstration Project at Reedsport, OR, will consist of 10 PowerBuoys located 2.5 miles off the coast. This U.S. Department of Energy Grant funding along with funding from PNGC Power, an Oregon‐based electric power cooperative, was utilized for the design completion, fabrication, assembly and factory testing of the first PowerBuoy for the Reedsport project. At this time, the design and fabrication of this first PowerBuoy and factory testing of the power take‐off subsystem are complete; additionally the power take‐off subsystem has been successfully integrated into the spar.« less

Grid tied PV/battery system architecture and power management for fast electric vehicle charging

NASA Astrophysics Data System (ADS)

Badawy, Mohamed O.

The prospective spread of Electric vehicles (EV) and plug-in hybrid electric vehicles (PHEV) arises the need for fast charging rates. Higher charging rates requirements lead to high power demands, which cant be always supported by the grid. Thus, the use of on-site sources alongside the electrical grid for EVs charging is a rising area of interest. In this dissertation, a photovoltaic (PV) source is used to support the high power EVs charging. However, the PV output power has an intermittent nature that is dependable on the weather conditions. Thus, battery storage are combined with the PV in a grid tied system, providing a steady source for on-site EVs use in a renewable energy based fast charging station. Verily, renewable energy based fast charging stations should be cost effective, efficient, and reliable to increase the penetration of EVs in the automotive market. Thus, this Dissertation proposes a novel power flow management topology that aims on decreasing the running cost along with innovative hardware solutions and control structures for the developed architecture. The developed power flow management topology operates the hybrid system at the minimum operating cost while extending the battery lifetime. An optimization problem is formulated and two stages of optimization, i.e online and offline stages, are adopted to optimize the batteries state of charge (SOC) scheduling and continuously compensate for the forecasting errors. The proposed power flow management topology is validated and tested with two metering systems, i.e unified and dual metering systems. The results suggested that minimal power flow is anticipated from the battery storage to the grid in the dual metering system. Thus, the power electronic interfacing system is designed accordingly. Interconnecting bi-directional DC/DC converters are analyzed, and a cascaded buck boost (CBB) converter is chosen and tested under 80 kW power flow rates. The need to perform power factor correction (PFC) on the grid power while supplying the battery storage and the DC loads inspired a novel dual switch control structure for the CBB AC/DC converter used in this dissertation. Thus, The CBB operates at a discontinuous capacitor voltage mode (DCVM) and the control structure enables for a non-distorted input current at overlapping output voltage levels. The PFC concept is validated and tested for a single phase rectifier and a 3 phase extension of the proposed concept is presented. Lastly, the PV source used in this study is required to supply power to both, the grid system, and to the DC loads, i.e the battery storage and the EVs. Thus, the PV panels used are connected in series to reach a desirable high voltage on the DC bus output of the PV system. Consequently, a novel differential power processing architecture is proposed in this dissertation. The proposed architecture enables each PV element to operate at its local maximum power point (MPP) while processing only a small portion of its total generated power through the distributed integrated converters. This leads to higher energy capture at an increased conversion efficiency while overcoming the difficulties associated with unmatched MPPs of the PV elements.

Portable thermo-photovoltaic power source

DOEpatents

Zuppero, Anthony C.; Krawetz, Barton; Barklund, C. Rodger; Seifert, Gary D.

1997-01-14

A miniature thermo-photovoltaic (TPV) device for generation of electrical power for use in portable electronic devices. A TPV power source is constructed to provide a heat source chemical reactor capable of using various fuels, such as liquid hydrocarbons, including but not limited to propane, LPG, butane, alcohols, oils and diesel fuels to generate a source of photons. A reflector dish guides misdirected photon energy from the photon source toward a photovoltaic array. A thin transparent protector sheet is disposed between the photon source and the array to reflect back thermal energy that cannot be converted to electricity, and protect the array from thermal damage. A microlens disposed between the protector sheet and the array further focuses the tailored band of photon energy from the photon source onto an array of photovoltaic cells, whereby the photon energy is converted to electrical power. A heat recuperator removes thermal energy from reactor chamber exhaust gases, preferably using mini- or micro-bellows to force air and fuel past the exhaust gases, and uses the energy to preheat the fuel and oxidant before it reaches the reactor, increasing system efficiency. Mini- or micro-bellows force ambient air through the system both to supply oxidant and to provide cooling. Finally, an insulator, which is preferably a super insulator, is disposed around the TPV power source to reduce fuel consumption, and to keep the TPV power source cool to the touch so it can be used in hand-held devices.

Trends and problems in development of the power plants electrical part

NASA Astrophysics Data System (ADS)

Gusev, Yu. P.

2015-03-01

The article discusses some problems relating to development of the electrical part of modern nuclear and thermal power plants, which are stemming from the use of new process and electrical equipment, such as gas turbine units, power converters, and intellectual microprocessor devices in relay protection and automated control systems. It is pointed out that the failure rates of electrical equipment at Russian and foreign power plants tend to increase. The ongoing power plant technical refitting and innovative development processes generate the need to significantly widen the scope of research works on the electrical part of power plants and rendering scientific support to works on putting in use innovative equipment. It is indicated that one of main factors causing the growth of electrical equipment failures is that some of components of this equipment have insufficiently compatible dynamic characteristics. This, in turn may be due to lack or obsolescence of regulatory documents specifying the requirements for design solutions and operation of electric power equipment that incorporates electronic and microprocessor control and protection devices. It is proposed to restore the system of developing new and updating existing departmental regulatory technical documents that existed in the 1970s, one of the fundamental principles of which was placing long-term responsibility on higher schools and leading design institutions for rendering scientific-technical support to innovative development of components and systems forming the electrical part of power plants. This will make it possible to achieve lower failure rates of electrical equipment and to steadily improve the competitiveness of the Russian electric power industry and energy efficiency of generating companies.

Temperature control of power semiconductor devices in traction applications

NASA Astrophysics Data System (ADS)

Pugachev, A. A.; Strekalov, N. N.

2017-02-01

The peculiarity of thermal management of traction frequency converters of a railway rolling stock is highlighted. The topology and the operation principle of the automatic temperature control system of power semiconductor modules of the traction frequency converter are designed and discussed. The features of semiconductors as an object of temperature control are considered; the equivalent circuit of thermal processes in the semiconductors is suggested, the power losses in the two-level voltage source inverters are evaluated and analyzed. The dynamic properties and characteristics of the cooling fan induction motor electric drive with the scalar control are presented. The results of simulation in Matlab are shown for the steady state of thermal processes.

A Demo opto-electronic power source based on single-walled carbon nanotube sheets.

PubMed

Hu, Chunhua; Liu, Changhong; Chen, Luzhuo; Meng, Chuizhou; Fan, Shoushan

2010-08-24

It is known that single-walled carbon nanotubes (SWNTs) strongly absorb light, especially in the near-infrared (NIR) region, and convert it into heat. In fact, SWNTs also have considerable ability to convert heat into electricity. In this work, we show that SWNT sheets made from as-grown SWNT arrays display a large positive thermoelectric coefficient (p-type). We designed a simple SWNT device to convert illuminating NIR light directly into a notable voltage output, which was verified by experimental tests. Furthermore, by a simple functionalization step, the p- to n-type transition was conveniently achieved for the SWNT sheets. By integrating p- and n-type elements in series, we constructed a novel NIR opto-electronic power source, which outputs a large voltage that sums over the output of every single element. Additionally, the output of the demo device has shown a good linear relationship with NIR light power density, favorable for IR sensors.

Improved SCR ac Motor Controller for Battery Powered Urban Electric Vehicles

NASA Technical Reports Server (NTRS)

Latos, T. S.

1982-01-01

An improved ac motor controller, which when coupled to a standard ac induction motor and a dc propulsion battery would provide a complete electric vehicle power train with the exception of the mechanical transmission and drive wheels was designed. In such a system, the motor controller converts the dc electrical power available at the battery terminals to ac electrical power for the induction motor in response to the drivers commands. The performance requirements of a hypothetical electric vehicle with an upper weight bound of 1590 kg (3500 lb) were used to determine the power rating of the controller. Vehicle acceleration capability, top speed, and gradeability requisites were contained in the Society of Automotive Engineers (SAE) Schedule 227a(d) driving cycle. The important capabilities contained in this driving cycle are a vehicle acceleration requirement of 0 to 72.4 kmph (0 to 45 mph) in 28 seconds a top speed of 88.5 kmph (55 mph), and the ability to negotiate a 10% grade at 48 kmph (30 mph). A 10% grade is defined as one foot of vertical rise per 10 feet of horizontal distance.

Formalization, equivalence and generalization of basic resonance electrical circuits

NASA Astrophysics Data System (ADS)

Penev, Dimitar; Arnaudov, Dimitar; Hinov, Nikolay

2017-12-01

In the work are presented basic resonance circuits, which are used in resonance energy converters. The following resonant circuits are considered: serial, serial with parallel load parallel capacitor, parallel and parallel with serial loaded inductance. For the circuits under consideration, expressions are generated for the frequencies of own oscillations and for the equivalence of the active power emitted in the load. Mathematical expressions are graphically constructed and verified using computer simulations. The results obtained are used in the model based design of resonant energy converters with DC or AC output. This guaranteed the output indicators of power electronic devices.

Molecular solid-state inverter-converter system

NASA Technical Reports Server (NTRS)

Birchenough, A. G.

1973-01-01

A modular approach for aerospace electrical systems has been developed, using lightweight high efficiency pulse width modulation techniques. With the modular approach, a required system is obtained by paralleling modules. The modular system includes the inverters and converters, a paralleling system, and an automatic control and fault-sensing protection system with a visual annunciator. The output is 150 V dc, or a low distortion three phase sine wave at 120 V, 400 Hz. Input power is unregulated 56 V dc. Each module is rated 2.5 kW or 3.6 kVA at 0.7 power factor.

Piezoelectric and semiconducting coupled power generating process of a single ZnO belt/wire. A technology for harvesting electricity from the environment.

PubMed

Song, Jinhui; Zhou, Jun; Wang, Zhong Lin

2006-08-01

This paper presents the experimental observation of piezoelectric generation from a single ZnO wire/belt for illustrating a fundamental process of converting mechanical energy into electricity at nanoscale. By deflecting a wire/belt using a conductive atomic force microscope tip in contact mode, the energy is first created by the deflection force and stored by piezoelectric potential, and later converts into piezoelectric energy. The mechanism of the generator is a result of coupled semiconducting and piezoelectric properties of ZnO. A piezoelectric effect is required to create electric potential of ionic charges from elastic deformation; semiconducting property is necessary to separate and maintain the charges and then release the potential via the rectifying behavior of the Schottky barrier at the metal-ZnO interface, which serves as a switch in the entire process. The good conductivity of ZnO is rather unique because it makes the current flow possible. This paper demonstrates a principle for harvesting energy from the environment. The technology has the potential of converting mechanical movement energy (such as body movement, muscle stretching, blood pressure), vibration energy (such as acoustic/ultrasonic wave), and hydraulic energy (such as flow of body fluid, blood flow, contraction of blood vessels) into electric energy that may be sufficient for self-powering nanodevices and nanosystems in applications such as in situ, real-time, and implantable biosensing, biomedical monitoring, and biodetection.

Sodium heat engine system: Space application

NASA Astrophysics Data System (ADS)

Betz, Bryan H.; Sungu, Sabri; Vu, Hung V.

1994-08-01

This paper explores the possibility of utilizing the Sodium Heat Engine (SHE) or known as AMTEC (Alkali Metal Thermoelectric Converter), for electrical power generation in ``near earth'' geosynchronous orbit. The Sodium Heat Engine principle is very flexible and adapts well to a variety of physical geometries. The proposed system can be easily folded and then deployed into orbit without the need for on site assembly in space. Electric power generated from SHE engine can be used in communication satellites, in space station, and other applications such as electrical recharging of vehicles in space is one of the applications the Sodium Heat Engine could be adapted to serve.

Electrodynamic tethers for energy conversion

NASA Technical Reports Server (NTRS)

Nobles, W.

1986-01-01

Conductive tethers have been proposed as a new method for converting orbital mechanical energy into electrical power for use on-board a satellite (generator mode) or conversely (motor mode) as a method of providing electric propulsion using electrical energy from the satellite. The operating characteristics of such systems are functionally dependent on orbit altitude and inclination. Effects of these relationships are examined to determine acceptable regions of application. To identify system design considerations, a specific set of system performance goals and requirements are selected. The case selected is for a 25 kW auxiliary power system for use on Space Station. Appropriate system design considerations are developed, and the resulting system is described.

The Electromagnetic Compatibility (EMC) Design Challenge for Scientific Spacecraft Powered by a Stirling Power Converter

NASA Technical Reports Server (NTRS)

Sargent, Noel B.

2001-01-01

A 55 We free-piston Stirling Technology Demonstration Convertor (TDC) has been tested as part of an evaluation to determine its feasibility as a means for significantly reducing the amount of radioactive material required compared to Radioisotope Thermoelectric Generators (RTGs) to support long-term space science missions. Measurements were made to quantify the low frequency magnetic and electric fields radiated from the Stirling's 80 Hertz (Hz) linear alternator and control electronics in order to determine the magnitude of reduction that will be required to protect sensitive field sensors aboard some science missions. One identified "Solar Probe" mission requires a 100 dB reduction in the low frequency magnetic field over typical military standard design limits, to protect its plasma wave sensor. This paper discusses the electromagnetic interference (EMI) control options relative to the physical design impacts for this power system, composed of 3 basic electrical elements. They are (1) the Stirling Power Convertor with its linear alternator, (2) the power switching and control electronics to convert the 90 V, 80 Hz alternator output to DC for the use of the spacecraft, and (3) the interconnecting wiring including any instrumentation to monitor and control items 1 and 2.

A 1.5-to-5 V converter for a battery-powered activity-dependent intracortical microstimulation SoC.

PubMed

Azin, Meysam; Mohseni, Pedram

2012-01-01

This paper reports on the design, analysis, implementation, and testing of a 1.5-to-5 V converter as part of a battery-powered activity-dependent intracortical microstimulation (ICMS) system-on-chip (SoC) that converts extracellular neural spikes recorded from one cortical area to electrical stimuli delivered to another cortical area in real time. The highly integrated voltage converter is intended to generate a 5-V supply for the stimulating back-end on the SoC from a miniature primary battery that powers the entire system. It is implemented in AMS 0.35 µm two-poly four-metal (2P/4M) complementary metal-oxide-semiconductor (CMOS) technology, employs only one external capacitor (1 µF) for storage, and delivers a maximum dc load current of ~88 µA with power efficiency of 31% with its output voltage adjusted to 5.05 V. This current drive capability affords simultaneous stimulation on all eight channels of the SoC with current amplitude up to ~100 µA and average stimulus rate >500 Hz, which is comfortably higher than firing rate of cortical neurons (<150 spikes per second). The measurement results also agree favorably with theoretical derivations from the analysis of converter operation.

Betavoltaic device in por-SiC/Si C-Nuclear Energy Converter

NASA Astrophysics Data System (ADS)

Akimchenko, Alina; Chepurnov, Victor; Dolgopolov, Mikhail; Gurskaya, Albina; Kuznetsov, Oleg; Mashnin, Alikhan; Radenko, Vitaliy; Radenko, Alexander; Surnin, Oleg; Zanin, George

2017-10-01

The miniature and low-power devices with long service life in hard operating conditions like the Carbon-14 beta-decay energy converters indeed as eternal resource for integrated MEMS and NEMS are considered. Authors discuss how to create the power supply for MEMS/NEMS devices, based on porous SiC/Si structure, which are tested to be used as the beta-decay energy converters of radioactive C-14 into electrical energy. This is based on the silicon carbide obtaining by self-organizing mono 3C-SiC endotaxy on the Si substrate. The new idea is the C-14 atoms including in molecules in the silicon carbide porous structure by this technology, which will increase the efficiency of the converter due to the greater intensity of electron-hole pairs generation rate in the space charge region. The synthesis of C-14 can be also performed by using the electronically controlled magneto-optic chamber.

Ground-Based High Energy Power Beaming in Support of Spacecraft Power Requirements

DTIC Science & Technology

2006-06-01

provide 900 W/m2. As more of the arriving energy is converted to space bus power and less goes into the production of heat , more solar cell output...similar control of peak power levels. Efficiency of power transfer may easily be about 50% as the solar cell experiences less heating effects as the...investigates the feasibility of projecting ground-based laser power to energize a spacecraft electrical bus via the solar panels. The energy is projected

Modeling and sizing the coil in boost converters dedicated to photovoltaic sources

NASA Astrophysics Data System (ADS)

Atik, Lotfi; Fares, Mohammed Amine; Zaraket, Jean; Bachir, Ghalem; Aillerie, Michel

2018-05-01

The coil is a very important element in a wide range of power electrical systems as such as those used in converter or inverter dedicated to extract and to adapt the value and the shape of the intensity and the voltage delivered by renewable energy sources. Thus, knowing its behavior in converters is paramount to obtain a maximum conversion efficiency and reliability. In this context, this paper presents a global study of a DC/DC boost converter dedicated to photovoltaic sources based on the modeling of the behavior of the coil or the inductance as a function of the switching frequency.

Integrated-magnetic apparatus

NASA Technical Reports Server (NTRS)

Bloom, Gordon E. (Inventor)

1998-01-01

Disclosure is made of an integrated-magnetic apparatus, comprising: winding structure for insulatingly carrying at least two generally flat, laterally offset and spaced apart electrical windings of a power converter around an aperture; a core having a flat exterior face, an interior cavity and an un-gapped core-column that is located within the cavity and that passes through the aperture of the winding structure; flat-sided surface carried by the core and forming an interior chamber that is located adjacent to the flat face of the core and forming a core-column that has a gap and that is located within the chamber; and structure, located around the gapped core-column, for carrying a third electrical winding of the power converter. The first two electrical windings are substantially located within the cavity and are adapted to be transformingly coupled together through the core. The third electrical winding is adapted to be inductively coupled through the gapped core-column to the other electrical windings, and is phased to have the magnetic flux passing through the gapped core-column substantially in the same direction as the magnetic flux passing through the un-gapped core-column and to have substantially the same AC components of flux in the gapped core-column and in the un-gapped core-column.

Electrothermal energy conversion using electron gas volumetric change inside semiconductors

NASA Astrophysics Data System (ADS)

Yazawa, K.; Shakouri, A.

2016-07-01

We propose and analyze an electrothermal energy converter using volumetric changes in non-equilibrium electron gas inside semiconductors. The geometric concentration of electron gas under an electric field increases the effective pressure of the electrons, and then a barrier filters out cold electrons, acting like a valve. Nano- and micro-scale features enable hot electrons to arrive at the contact in a short enough time to avoid thermalization with the lattice. Key length and time scales, preliminary device geometry, and anticipated efficiency are estimated for electronic analogs of Otto and Brayton power generators and Joule-Thomson micro refrigerators on a chip. The power generators convert the energy of incident photons from the heat source to electrical current, and the refrigerator can reduce the temperature of electrons in a semiconductor device. The analytic calculations show that a large energy conversion efficiency or coefficient of performance may be possible.

Prospects and applicability of wave energy for South Africa

NASA Astrophysics Data System (ADS)

Lavidas, George; Venugopal, Vengatesan

2018-03-01

Renewable energy offers significant opportunities for electricity diversification. South Africa belongs to the group of developing nations and encompasses a lot of potential for renewable energy developments. Currently, the majority of its electricity production originates from fossil fuels; however, incorporation of clean coal technologies will aid in reaching the assigned targets. This study offers a long-term wave power quantification analysis with a numerical wave model. The investigation includes long-term resource assessment in the region, variability, seasonal and monthly wave energy content. Locations with high-energy content but low variability pose an opportunity that can contribute in the alleviation of energy poverty. Application of wave converters depends on the combination of complex terms. The study presents resource levels and the joint distributions, which indicate suitability for converter selection. Depending on the region of interest, these characteristics change. Thus, this resource assessment adds knowledge on wave power and optimal consideration for wave energy applicability.

Comparative assessment of out-of-core nuclear thermionic power systems

NASA Technical Reports Server (NTRS)

Estabrook, W. C.; Koenig, D. R.; Prickett, W. Z.

1975-01-01

The hardware selections available for fabrication of a nuclear electric propulsion stage for planetary exploration were explored. The investigation was centered around a heat-pipe-cooled, fast-spectrum nuclear reactor for an out-of-core power conversion system with sufficient detail for comparison with the in-core system studies completed previously. A survey of competing power conversion systems still indicated that the modular reliability of thermionic converters makes them the desirable choice to provide the 240-kWe end-of-life power for at least 20,000 full power hours. The electrical energy will be used to operate a number of mercury ion bombardment thrusters with a specific impulse in the range of about 4,000-5,000 seconds.

Accelerated Aging with Electrical Overstress and Prognostics for Power MOSFETs

NASA Technical Reports Server (NTRS)

Saha, Sankalita; Celaya, Jose Ramon; Vashchenko, Vladislav; Mahiuddin, Shompa; Goebel, Kai F.

2011-01-01

Power electronics play an increasingly important role in energy applications as part of their power converter circuits. Understanding the behavior of these devices, especially their failure modes as they age with nominal usage or sudden fault development is critical in ensuring efficiency. In this paper, a prognostics based health management of power MOSFETs undergoing accelerated aging through electrical overstress at the gate area is presented. Details of the accelerated aging methodology, modeling of the degradation process of the device and prognostics algorithm for prediction of the future state of health of the device are presented. Experiments with multiple devices demonstrate the performance of the model and the prognostics algorithm as well as the scope of application. Index Terms Power MOSFET, accelerated aging, prognostics

Design and fabrication of six-volt vertically-stacked GaAs photovoltaic power converter

PubMed Central

Zhao, Yongming; Sun, Yurun; He, Yang; Yu, Shuzhen; Dong, Jianrong

2016-01-01

A six-volt vertically-stacked, high current GaAs photovoltaic power converter (PPC) has been designed and fabricated to produce output power over 1 W under monochromatic illumination. An N++-GaAs/P++-AlGaAs tunnel junctions (TJs) structure has been used for connecting each sub-cell in this vertically-stacked PPC device. The thickness of the each GaAs sub-cell has been derived based on the calculation of absorption depth of photons with a wavelength of 808 nm using absorption coefficient obtained from ellipsometry measurements. The devices were characterized under non-uniform CW laser illumination at 808 nm with incident power up to 4.1 W. A maximum conversion efficiency of 50.2% was achieved at 0.3 W under non-uniform (coupled in optical fiber) monochromatic illumination, dropping to 42.5% at 4.1 W. The operating voltage at the maximum power point is 5.5–6.0 V, depending on the incident laser power, and an output electrical power output of 1.3 W can be extracted at a laser power of 2.9 W and the maximum electrical power output amounts to 1.72 W. The external quantum efficiency (EQE) measurement indicates that the performance of PPC can be further improved by refining the design of the thickness of sub-cells and improving TJs. PMID:27901079

Superconducting magnetic energy storage for asynchronous electrical systems

DOEpatents

Boenig, Heinrich J.

1986-01-01

A superconducting magnetic energy storage coil connected in parallel between converters of two or more ac power systems provides load leveling and stability improvement to any or all of the ac systems. Control is provided to direct the charging and independently the discharging of the superconducting coil to at least a selected one of the ac power systems.

Metamaterial Absorbers for Microwave Detection

DTIC Science & Technology

2015-06-01

duration, high-power electrical pulses into electromagnetic waves. 6  A mode converter to tailor the spatial distribution of the electromagnetic ...congressional-report/113th-congress/senate- report/211/1. [16] C. Wilson, “High altitude electromagnetic pulse and high power microwave devices...and Communications CRS Congressional Report Services DE Directed Energy DEW Directed Energy Weapons EM Electromagnetic EMS

Review of thin film solar cell technology and applications for ultra-light spacecraft solar arrays

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.

1991-01-01

Developments in thin-film amorphous and polycrystalline photovoltaic cells are reviewed and discussed with a view to potential applications in space. Two important figures of merit are discussed: efficiency (i.e., what fraction of the incident solar energy is converted to electricity), and specific power (power to weight ratio).

A 928 sq m (10000 sq ft) solar array

NASA Technical Reports Server (NTRS)

Lindberg, D. E.

1972-01-01

As the power requirements for space vehicles increases, the area of solar arrays that convert solar energy to usable electrical power increases. The requirements for a 928 sq m (10,000 sq ft) array, its design, and a full-scale demonstration of one quadrant (232 sq m (2500 sq ft)) deployed in a one-g field are described.

Harmonics analysis of the ITER poloidal field converter based on a piecewise method

NASA Astrophysics Data System (ADS)

Xudong, WANG; Liuwei, XU; Peng, FU; Ji, LI; Yanan, WU

2017-12-01

Poloidal field (PF) converters provide controlled DC voltage and current to PF coils. The many harmonics generated by the PF converter flow into the power grid and seriously affect power systems and electric equipment. Due to the complexity of the system, the traditional integral operation in Fourier analysis is complicated and inaccurate. This paper presents a piecewise method to calculate the harmonics of the ITER PF converter. The relationship between the grid input current and the DC output current of the ITER PF converter is deduced. The grid current is decomposed into the sum of some simple functions. By calculating simple function harmonics based on the piecewise method, the harmonics of the PF converter under different operation modes are obtained. In order to examine the validity of the method, a simulation model is established based on Matlab/Simulink and a relevant experiment is implemented in the ITER PF integration test platform. Comparative results are given. The calculated results are found to be consistent with simulation and experiment. The piecewise method is proved correct and valid for calculating the system harmonics.

Nuclear energy waste-space transportation and removal

NASA Technical Reports Server (NTRS)

Burns, R. E.

1975-01-01

A method for utilizing the decay heat of actinide wastes to power an electric thrust vehicle is proposed. The vehicle, launched by shuttle to earth orbit and to earth escape by a tug, obtains electrical power from the actinide waste heat by thermionic converters. The heavy gamma ray and neutron shielding which is necessary as a safety feature is removed in orbit and returned to earth for reuse. The problems associated with safety are dealt with in depth. A method for eliminating fission wastes via chemical propulsion is briefly discussed.

An exact analysis of a rectangular plate piezoelectric generator.

PubMed

Yang, Jiashi; Chen, Ziguang; Hu, Yuantai

2007-01-01

We study thickness-twist vibration of a finite, piezoelectric plate of polarized ceramics or 6-mm crystals driven by surface mechanical loads. An exact solution from the three-dimensional equations of piezoelectricity is obtained. The plate is properly electroded and connected to a circuit such that an electric output is generated. The structure analyzed represents a piezoelectric generator for converting mechanical energy to electrical energy. Analytical expressions for the output voltage, current, power, efficiency, and power density are given. The basic behaviors of the generator are shown by numerical results.

A Bidirectional High-Power-Quality Grid Interface With a Novel Bidirectional Noninverted Buck Boost Converter for PHEVs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Onar, Omer C

2012-01-01

Plug-in hybrid electric vehicles (PHEVs) will play a vital role in future sustainable transportation systems due to their potential in terms of energy security, decreased environmental impact, improved fuel economy, and better performance. Moreover, new regulations have been established to improve the collective gas mileage, cut greenhouse gas emissions, and reduce dependence on foreign oil. This paper primarily focuses on two major thrust areas of PHEVs. First, it introduces a grid-friendly bidirectional alternating current/direct current ac/dc dc/ac rectifier/inverter for facilitating vehicle-to-grid (V2G) integration of PHEVs. Second, it presents an integrated bidirectional noninverted buck boost converter that interfaces the energy storagemore » device of the PHEV to the dc link in both grid-connected and driving modes. The proposed bidirectional converter has minimal grid-level disruptions in terms of power factor and total harmonic distortion, with less switching noise. The integrated bidirectional dc/dc converter assists the grid interface converter to track the charge/discharge power of the PHEV battery. In addition, while driving, the dc/dc converter provides a regulated dc link voltage to the motor drive and captures the braking energy during regenerative braking.« less

Power SEMICONDUCTORS—STATE of Art and Future Trends

NASA Astrophysics Data System (ADS)

Benda, Vitezslav

2011-06-01

The importance of effective energy conversion control, including power generation from renewable and environmentally clean energy sources, increases due to rising energy demand. Power electronic systems for controlling and converting electrical energy have become the workhorse of modern society in many applications, both in industry and at home. Power electronics plays a very important role in traction and can be considered as brawns of robotics and automated manufacturing systems. Power semiconductor devices are the key electronic components used in power electronic systems. Advances in power semiconductor technology have improved the efficiency, size, weight and cost of power electronic systems. At present, IGCTs, IGBTs, and MOSFETs represent modern switching devices. Power integrated circuits (PIC) have been developed for the use of power converters for portable, automotive and aerospace applications. For advanced applications, new materials (SiC and GaN) have been introduced. This paper reviews the state of these devices and elaborates on their potentials in terms of higher voltages, higher power density, and better switching performance.

Liquid metal thermal electric converter

DOEpatents

Abbin, Joseph P.; Andraka, Charles E.; Lukens, Laurance L.; Moreno, James B.

1989-01-01

A liquid metal thermal electric converter which converts heat energy to electrical energy. The design of the liquid metal thermal electric converter incorporates a unique configuration which directs the metal fluid pressure to the outside of the tube which results in the structural loads in the tube to be compressive. A liquid metal thermal electric converter refluxing boiler with series connection of tubes and a multiple cell liquid metal thermal electric converter are also provided.

Thermal Diagrams of Thermo-Electrical Devices (Selected Chapters)

DTIC Science & Technology

1974-10-09

for example silicides ) the electric-spark treatment is a long process; thus, this method is unsuitable for obtaining a large number of holes...converters for marine use were developed with useful electric power of 500- 2000 W. Sodium -potassium eutectic was used both for supplying the heat from...oxidizing mdiu•r. In view of this fact it is advisable at present to examine onlýy the silicides of certain metals that are stable under the ettnr, con

Multi-time scale dynamics in power electronics-dominated power systems

NASA Astrophysics Data System (ADS)

Yuan, Xiaoming; Hu, Jiabing; Cheng, Shijie

2017-09-01

Electric power infrastructure has recently undergone a comprehensive transformation from electromagnetics to semiconductors. Such a development is attributed to the rapid growth of power electronic converter applications in the load side to realize energy conservation and on the supply side for renewable generations and power transmissions using high voltage direct current transmission. This transformation has altered the fundamental mechanism of power system dynamics, which demands the establishment of a new theory for power system control and protection. This paper presents thoughts on a theoretical framework for the coming semiconducting power systems.

Lightweight Integrated Solar Array and Transceiver. [Improving Electrical Power and Communication Capabilities in Small Spacecraft

NASA Technical Reports Server (NTRS)

Carr, John; Martinez, Andres; Petro, Andrew

2015-01-01

The Lightweight Integrated Solar Array and Transceiver (LISA-T) project will leverage several existing and on-going efforts at Marshall Space Flight Center (MSFC) for the design, development, fabrication, and test of a launch stowed, orbit deployed structure on which thin-film photovoltaics for power generation and antenna elements for communication, are embedded. Photovoltaics is a method for converting solar energy into electricity using semiconductor materials. The system will provide higher power generation with a lower mass, smaller stowage volume, and lower cost than the state of the art solar arrays, while simultaneously enabling deployable antenna concepts.

Optically powered remote gas monitor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dubaniewicz, T.H. Jr.; Chilton, J.E.

1995-12-31

Many mines rely on toxic gas sensors to help maintain a safe and healthy work environment. This report describes a prototype monitoring system developed by the US Bureau of Mines (USBM) that uses light to power and communicate with several remote toxic gas sensors. The design is based on state-of-art optical-to-electrical power converters, solid-state diode lasers, and fiber optics. This design overcomes several problems associated with conventional wire-based systems by providing complete electrical isolation between the remote sensors and the central monitor. The prototype performed well during a 2-week field trial in the USBM Pittsburgh Research Center Safety Research Coalmore » Mine.« less

Using a coupled inductor controlled by fuzzy logic to improve the efficiency of a Buck converter in a PV system

NASA Astrophysics Data System (ADS)

Abouchabana, Nabil; Haddadi, Mourad; Rabhi, Abdelhamid; El Hajjaji, Ahmed

2017-11-01

Photovoltaic generators (PVG) produce a variable power according to the solar radiation (G) and temperature (T). This variation affects the sizing of the components of DC / DC converters, powered by such PVG, and make it difficult. The effects may differ from one component to another. The main and critical one is presented by the inductor, the element that stores the energy during sampled periods. We propose in this work an auto-adaptation of these inductor values to maintain optimal performance of the power yield of these converters. Our idea is to replace the inductor by a coupled inductor where this adjustment is made by the addition of an adjustable electric field in the magnetic core. Low current intensities come from the PVG supply the second inductor of the coupled inductor through a circuit controlled by a fuzzy controller (FC). The whole system is modeled and simulated under MATLAB/SIMULINK for the control part of the system and under PSPICE for the power part of the system. The obtained results show good performances of the proposed converter over the standard one.

Trimode Power Converter optimizes PV, diesel and battery energy sources

NASA Astrophysics Data System (ADS)

Osullivan, George; Bonn, Russell; Bower, Ward

1994-12-01

Conservatively, there are 100,000 localities in the world waiting for the benefits that electricity can provide, and many of these are in climates where sunshine is plentiful. With these locations in mind a prototype 30 kW hybrid system has been assembled at Sandia to prove the reliability and economics of photovoltaic, diesel and battery energy sources managed by an autonomous power converter. In the Trimode Power Converter the same power parts, four IGBT's with an isolation transformer and filter components, serve as rectifier and charger to charge the battery from the diesel; as a stand-alone inverter to convert PV and battery energy to AC; and, as a parallel inverter with the diesel-generator to accommodate loads larger than the rating of the diesel. Whenever the diesel is supplying the load, an algorithm assures that the diesel is running at maximum efficiency by regulating the battery charger operating point. Given the profile of anticipated solar energy, the cost of transporting diesel fuel to a remote location and a five year projection of load demand, a method to size the PV array, battery and diesel for least cost is developed.

Artificial neural networks for control of a grid-connected rectifier/inverter under disturbance, dynamic and power converter switching conditions.

PubMed

Li, Shuhui; Fairbank, Michael; Johnson, Cameron; Wunsch, Donald C; Alonso, Eduardo; Proaño, Julio L

2014-04-01

Three-phase grid-connected converters are widely used in renewable and electric power system applications. Traditionally, grid-connected converters are controlled with standard decoupled d-q vector control mechanisms. However, recent studies indicate that such mechanisms show limitations in their applicability to dynamic systems. This paper investigates how to mitigate such restrictions using a neural network to control a grid-connected rectifier/inverter. The neural network implements a dynamic programming algorithm and is trained by using back-propagation through time. To enhance performance and stability under disturbance, additional strategies are adopted, including the use of integrals of error signals to the network inputs and the introduction of grid disturbance voltage to the outputs of a well-trained network. The performance of the neural-network controller is studied under typical vector control conditions and compared against conventional vector control methods, which demonstrates that the neural vector control strategy proposed in this paper is effective. Even in dynamic and power converter switching environments, the neural vector controller shows strong ability to trace rapidly changing reference commands, tolerate system disturbances, and satisfy control requirements for a faulted power system.

Bifurcation Analysis of a DC-DC Bidirectional Power Converter Operating with Constant Power Loads

NASA Astrophysics Data System (ADS)

Cristiano, Rony; Pagano, Daniel J.; Benadero, Luis; Ponce, Enrique

Direct current (DC) microgrids (MGs) are an emergent option to satisfy new demands for power quality and integration of renewable resources in electrical distribution systems. This work addresses the large-signal stability analysis of a DC-DC bidirectional converter (DBC) connected to a storage device in an islanding MG. This converter is responsible for controlling the balance of power (load demand and generation) under constant power loads (CPLs). In order to control the DC bus voltage through a DBC, we propose a robust sliding mode control (SMC) based on a washout filter. Dynamical systems techniques are exploited to assess the quality of this switching control strategy. In this sense, a bifurcation analysis is performed to study the nonlinear stability of a reduced model of this system. The appearance of different bifurcations when load parameters and control gains are changed is studied in detail. In the specific case of Teixeira Singularity (TS) bifurcation, some experimental results are provided, confirming the mathematical predictions. Both a deeper insight in the dynamic behavior of the controlled system and valuable design criteria are obtained.

ISS EPS Orbital Replacement Unit Block Diagrams

NASA Technical Reports Server (NTRS)

Schmitz, Gregory V.

2001-01-01

The attached documents are being provided to Switching Power Magazine for information purposes. This magazine is writing a feature article on the International Space Station Electrical Power System, focusing on the switching power processors. These units include the DC-DC Converter Unit (DDCU), the Bi-directional Charge/Discharge Unit (BCDU), and the Sequential Shunt Unit (SSU). These diagrams are high-level schematics/block diagrams depicting the overall functionality of each unit.

Design of a magnetic force exciter for a small-scale windmill using a piezo-composite generating element

NASA Astrophysics Data System (ADS)

Luong, Hung Truyen; Goo, Nam Seo

2011-03-01

We introduce a design for a magnetic force exciter that applies vibration to a piezo-composite generating element (PCGE) for a small-scale windmill to convert wind energy into electrical energy. The windmill can be used to harvest wind energy in urban regions. The magnetic force exciter consists of exciting magnets attached to the device's input rotor, and a secondary magnet that is fixed at the tip of the PCGE. Under an applied wind force, the input rotor rotates to create a magnetic force interaction to excite the PCGE. Deformation of the PCGE enables it to generate the electric power. Experiments were performed to test power generation and battery charging capabilities. In a battery charging test, the charging time for a 40 mAh battery is approximately 1.5 hours for a wind speed of 2.5 m/s. Our experimental results show that the prototype can harvest energy in urban areas with low wind speeds, and convert the wasted wind energy into electricity for city use.

A Thermally-Regenerative Ammonia-Based Flow Battery for Electrical Energy Recovery from Waste Heat.

PubMed

Zhu, Xiuping; Rahimi, Mohammad; Gorski, Christopher A; Logan, Bruce

2016-04-21

Large amounts of low-grade waste heat (temperatures <130 °C) are released during many industrial, geothermal, and solar-based processes. Using thermally-regenerative ammonia solutions, low-grade thermal energy can be converted to electricity in battery systems. To improve reactor efficiency, a compact, ammonia-based flow battery (AFB) was developed and tested at different solution concentrations, flow rates, cell pairs, and circuit connections. The AFB achieved a maximum power density of 45 W m(-2) (15 kW m(-3) ) and an energy density of 1260 Wh manolyte (-3) , with a thermal energy efficiency of 0.7 % (5 % relative to the Carnot efficiency). The power and energy densities of the AFB were greater than those previously reported for thermoelectrochemical and salinity-gradient technologies, and the voltage or current could be increased using stacked cells. These results demonstrated that an ammonia-based flow battery is a promising technology to convert low-grade thermal energy to electricity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Control Structures for VSC-based FACTS Devices under Normal and Faulted AC-systems

NASA Astrophysics Data System (ADS)

Babaei, Saman

This thesis is concerned with improving the Flexible AC Transmission Systems (FACTS) devices performance under the normal and fault AC-system conditions by proposing new control structures and also converter topologies. The combination of the increasing electricity demand and restrictions in expanding the power system infrastructures has urged the utility owners to deploy the utility-scaled power electronics in the power system. Basically, FACTS is referred to the application of the power electronics in the power systems. Voltage Source Converter (VSC) is the preferred building block of the FACTS devices and many other utility-scale power electronics applications. Despite of advances in the semiconductor technology and ultra-fast microprocessor based controllers, there are still many issues to address and room to improve[25]. An attempt is made in this thesis to address these important issues of the VSC-based FACTS devices and provide solutions to improve them.

Etude et simulation de la MADA

NASA Astrophysics Data System (ADS)

Defontaines, Remi

Over the past ten years, the production of electric energy using wind turbines has increased eight times. This production of energy is in full expansion, and different means are now at the dispositions of researchers to finally explore it to the maximum. The DFIG is a type of wind turbine that has been the object of numerous studies over the past several years. This wind turbine functions with the speed of the wind. Its principle particularity is that it is constituted of an asynchronous machine, a wound-rotor and is capable of providing active power to the network by the stator and the rotor. This structure permits a good performance over a wide range of wind speeds, at a reasonable cost. It manages to be cost-effective because it uses weakly dimensioned power converters. Despite its advantages, there is a problem: its connection to the network. The electric network is not always stable; it regularly suffers voltage damage (low voltage, unbalance or overvoltage). This damage can result in fault from poor quality in the machine, and this damages or even destroys the power converters. To avoid this issue, the wind turbine disconnects from the network when it undergoes deterioration. The goal of this research is to find a strategy that allows the wind turbine to function even when the network voltage deteriorates, which in turn results in avoiding disconnection and therefore the loss of electrical power.

New approaches to provide ride-through for critical loads in electric power distribution systems

NASA Astrophysics Data System (ADS)

Montero-Hernandez, Oscar C.

2001-07-01

The extensive use of electronic circuits has enabled modernization, automation, miniaturization, high quality, low cost, and other achievements regarding electric loads in the last decades. However, modern electronic circuits and systems are extremely sensitive to disturbances from the electric power supply. In fact, the rate at which these disturbances happen is considerable as has been documented in recent years. In response to the power quality concerns presented previously, this dissertation is proposing new approaches to provide ride-through for critical loads during voltage disturbances with emphasis on voltage sags. In this dissertation, a new approach based on an AC-DC-AC system is proposed to provide ride-through for critical loads connected in buildings and/or an industrial system. In this approach, a three-phase IGBT inverter with a built in Dc-link voltage regulator is suitably controlled along with static by-pass switches to provide continuous power to critical loads. During a disturbance, the input utility source is disconnected and the power from the inverter is connected to the load. The remaining voltage in the AC supply is converted to DC and compensated before being applied to the inverter and the load. After detecting normal utility conditions, power from the utility is restored to the critical load. In order to achieve an extended ride-through capability a second approach is introduced. In this case, the Dc-link voltage regulator is performed by a DC-DC Buck-Boost converter. This new approach has the capability to mitigate voltage variations below and above the nominal value. In the third approach presented in this dissertation, a three-phase AC to AC boost converter is investigated. This converter provides a boosting action for the utility input voltages, right before they are applied to the load. The proposed Pulse Width Modulation (PWM) control strategy ensures independent control of each phase and compensates for both single-phase or poly-phase voltage sags. Algorithms capable of detecting voltage disturbances such as voltage sags, voltage swells, flicker, frequency change, and harmonics in a fast and reliable way are investigated and developed in this dissertation as an essential part of the approaches previously described. Simulation and experimental work has been done to validate the feasibility of all approaches under the most common voltage disturbances such as single-phase voltage sags and three-phase voltage sags.

NREL, Wyle and U.S. Army Developed Consolidated Utility Base Energy System

Science.gov Websites

the CUBE in peak-shaving mode. The CUBE converts power from different sources (such as solar panels , batteries, and generators) into usable electricity-and swiftly switches between different sources for an

Development and evaluation of a long-term, implantable, electrically actuated left ventricular assist system: THI/Gould LVAS.

PubMed

Norman, J C; McGee, M G; Fuqua, J M; Igo, S R; Turner, S A; Sterling, R; Urrutia, C O; Frazier, O H; Clay, W C; Chambers, J A

1983-02-01

A long-term, implantable, electrically actuated left ventricular assist system (THI/Gould LVAS) is being developed and characterized in vitro and in vivo for utilization in patients with end-stage heart disease. This system consists of five major components: a long-term, implantable blood pump (THI E-type ALVAD); an electrical-mechanical energy converter (Gould Model V); a control unit with batteries; a volume compensation system; and an external power supply and monitoring unit. Two of these components (blood pump and electrical-mechanical energy converter) have been integrated, and are undergoing chronic in vivo evaluations in calves. Thus far, 44 pneumatically and electrically actuated THI/Gould LVAS evaluations have been performed. This experience has resulted in greater than 6.5 years of actuation in vivo, with durations exceeding 1 year. System in vivo performance in terms of durability, mechanical reliability, hemodynamic effectiveness, and biocompatibility has been satisfactory. Demonstration of long-term (2-year) effectiveness in supporting the circulation is the ultimate goal.

Space Solar Power Satellite Technology Development at the Glenn Research Center: An Overview

NASA Technical Reports Server (NTRS)

Dudenhoefer, James E.; George, Patrick J.

2000-01-01

NASA Glenn Research Center (GRC). is participating in the Space Solar Power Exploratory Research and Technology program (SERT) for the development of a solar power satellite concept. The aim of the program is to provide electrical power to Earth by converting the Sun's energy and beaming it to the surface. This paper will give an overall view of the technologies being pursued at GRC including thin film photovoltaics, solar dynamic power systems, space environmental effects, power management and distribution, and electric propulsion. The developmental path not only provides solutions to gigawatt sized space power systems for the future, but provides synergistic opportunities for contemporary space power architectures. More details of Space Solar Power can be found by reading the references sited in this paper and by connecting to the web site http://moonbase.msfc.nasa.gov/ and accessing the "Space Solar Power" section "Public Access" area.

Systems Analysis of GPS Electrical Power System Redesign

DTIC Science & Technology

1995-12-01

Table 8 - System Efficiencies & Multipliers for Solar Direct Model (12:102; 15:864) Component Efficiency AMTEC 0.180 Receiver and Thermal Energy Storage...and low temperatures of the working fluid. Extreme high and low temperatures provide a greater efficiency , but require extensive thermal control and...direct conversion category. The Alkali Metal Thermal -to-Electric Converter ( AMTEC ) shows mass and cost savings due to efficiencies significantly higher

High efficiency thermoelectric power generation using Zintl-type materials

NASA Technical Reports Server (NTRS)

Brown, Shawna (Inventor); Snyder, G. Jeffrey (Inventor); Gascoin, Franck (Inventor); Kauzlarich, Susan (Inventor)

2010-01-01

The invention disclosed herein relates to thermoelectrically-active p-type Zintl phase materials as well as devices utilizing such compounds. Such thermoelectric materials and devices may be used to convert thermal energy into electrical energy, or use electrical energy to produce heat or refrigeration. Embodiments of the invention relate to p-type thermoelectric materials related to the compound Yb.sub.14MnSb.sub.11.

Emissivity Tuned Emitter for RTPV Power Sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carl M. Stoots; Robert C. O'Brien; Troy M. Howe

Every mission launched by NASA to the outer planets has produced unexpected results. The Voyager I and II, Galileo, and Cassini missions produced images and collected scientific data that totally revolutionized our understanding of the solar system and the formation of the planetary systems. These missions were enabled by the use of nuclear power. Because of the distances from the Sun, electrical power was produced using the radioactive decay of a plutonium isotope. Radioisotopic Thermoelectric Generators (RTGs) used in the past and currently used Multi-Mission RTGs (MMRTGs) provide power for space missions. Unfortunately, RTGs rely on thermocouples to convert heatmore » to electricity and are inherently inefficient ({approx} 3-7% thermal to electric efficiency). A Radioisotope Thermal Photovoltaic (RTPV) power source has the potential to reduce the specific mass of the onboard power supply by increasing the efficiency of thermal to electric conversion. In an RTPV, a radioisotope heats an emitter, which emits light to a photovoltaic (PV) cell, which converts the light into electricity. Developing an emitter tuned to the desired wavelength of the photovoltaic is a key part in increasing overall performance. Researchers at the NASA Glenn Research Center (GRC) have built a Thermal Photovoltaic (TPV) system, that utilizes a simulated General Purpose Heat Source (GPHS) from a MMRTG to heat a tantalum emitter. The GPHS is a block of graphite roughly 10 cm by 10 cm by 5 cm. A fully loaded GPHS produces 250 w of thermal power and weighs 1.6 kgs. The GRC system relies on the GPHS unit radiating at 1200 K to a tantalum emitter that, in turn, radiates light to a GaInAs photo-voltaic cell. The GRC claims system efficiency of conversion of 15%. The specific mass is around 167 kg/kWe. A RTPV power source that utilized a ceramic or ceramic-metal (cermet) matrix would allow for the combination of the heat source, canister, and emitter into one compact unit, and allow variation in size and shape to optimize temperature and emission spectra.« less

Development of a Low Inductance Linear Alternator for Stirling Power Convertors

NASA Technical Reports Server (NTRS)

Geng, Steven M.; Schifer, Nicholas A.

2017-01-01

The free-piston Stirling power convertor is a promising technology for high efficiency heat-to-electricity power conversion in space. Stirling power convertors typically utilize linear alternators for converting mechanical motion into electricity. The linear alternator is one of the heaviest components of modern Stirling power convertors. In addition, state-of-art Stirling linear alternators usually require the use of tuning capacitors or active power factor correction controllers to maximize convertor output power. The linear alternator to be discussed in this paper, eliminates the need for tuning capacitors and delivers electrical power output in which current is inherently in phase with voltage. No power factor correction is needed. In addition, the linear alternator concept requires very little iron, so core loss has been virtually eliminated. This concept is a unique moving coil design where the magnetic flux path is defined by the magnets themselves. This paper presents computational predictions for two different low inductance alternator configurations, and compares the predictions with experimental data for one of the configurations that has been built and is currently being tested.

Development of a Low-Inductance Linear Alternator for Stirling Power Convertors

NASA Technical Reports Server (NTRS)

Geng, Steven M.; Schifer, Nicholas A.

2017-01-01

The free-piston Stirling power convertor is a promising technology for high-efficiency heat-to-electricity power conversion in space. Stirling power convertors typically utilize linear alternators for converting mechanical motion into electricity. The linear alternator is one of the heaviest components of modern Stirling power convertors. In addition, state-of-the-art Stirling linear alternators usually require the use of tuning capacitors or active power factor correction controllers to maximize convertor output power. The linear alternator to be discussed in this paper eliminates the need for tuning capacitors and delivers electrical power output in which current is inherently in phase with voltage. No power factor correction is needed. In addition, the linear alternator concept requires very little iron, so core loss has been virtually eliminated. This concept is a unique moving coil design where the magnetic flux path is defined by the magnets themselves. This paper presents computational predictions for two different low inductance alternator configurations. Additionally, one of the configurations was built and tested at GRC, and the experimental data is compared with the predictions.

Proposal for conversion of end use equipment and service from AC to DC for enhanced benefits from photovoltaics and fuel cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wicks, F.

1998-07-01

The need to produce electricity either more fuel efficiently or without need for consuming fuel is well recognized. Fuel cells are typically suggested for higher efficiency and photovoltaics can produce electricity directly from the sun. However, both of these devices produce direct current which is not compatible with the existing ac power system. The typical options of installing AC to DC inverters and the dedication of this DC generation to DC loads and storage are costly and inefficient. Thus, the author suggests it would be better in terms of energy conservation and public policy to convert end use service tomore » DC for direct compatibility with this DC generation, as a first step toward conversion to a new and better type of electric power system that can be described as a solid state power electronics based multiple voltage DC power system.« less

Advantage of incorporating geothermal energy into power-station cycles

NASA Astrophysics Data System (ADS)

White, A. A. L.

1980-06-01

The generation of electricity from low-temperature geothermal sources has been hampered by the low conversion efficiencies of Rankine cycle operating below 150 C. It is shown how the electrical output derived from a geothermal borehole may be substantially improved on that expected from these cycles by incorporating the geothermal heat into a conventional steam-cycle power station to provide feedwater heating. This technique can yield thermal conversion efficiencies of 11% which, for a well-head temperature of 100 C, is 50% greater than the output expected from a Rankine cycle. Coupled with the smaller capital costs involved, feedwater heating is thus a more attractive technique of converting heat into electricity. Although power stations above suitable geothermal resources would ideally have the geothermal heat incorporated from the design stage, experiments at Marchwood Power Station have shown that small existing sets can be modified to accept geothermal feedwater heating.

Modeling, analysis and control of fuel cell hybrid power systems

NASA Astrophysics Data System (ADS)

Suh, Kyung Won

Transient performance is a key characteristic of fuel cells, that is sometimes more critical than efficiency, due to the importance of accepting unpredictable electric loads. To fulfill the transient requirement in vehicle propulsion and portable fuel cell applications, a fuel cell stack is typically coupled with a battery through a DC/DC converter to form a hybrid power system. Although many power management strategies already exist, they all rely on low level controllers that realize the power split. In this dissertation we design controllers that realize various power split strategies by directly manipulating physical actuators (low level commands). We maintain the causality of the electric dynamics (voltage and current) and investigate how the electric architecture affects the hybridization level and the power management. We first establish the performance limitations associated with a stand-alone and power-autonomous fuel cell system that is not supplemented by an additional energy storage and powers all its auxiliary components by itself. Specifically, we examine the transient performance in fuel cell power delivery as it is limited by the air supplied by a compressor driven by the fuel cell itself. The performance limitations arise from the intrinsic coupling in the fluid and electrical domain between the compressor and the fuel cell stack. Feedforward and feedback control strategies are used to demonstrate these limitations analytically and with simulations. Experimental tests on a small commercial fuel cell auxiliary power unit (APU) confirm the dynamics and the identified limitations. The dynamics associated with the integration of a fuel cell system and a DC/DC converter is then investigated. Decentralized and fully centralized (using linear quadratic techniques) controllers are designed to regulate the power system voltage and to prevent fuel cell oxygen starvation. Regulating these two performance variables is a difficult task and requires a compromise due to the conflicting objectives. The compromise can be mitigated by augmenting the fuel cell power system with an energy buffer such as a battery. We consider two different and popular ways of connecting the battery and the fuel cell to the load and we refer to them as electric architectures. Various controller gains are used to span the fuel cell operation from load-following to load-leveling, and hence, to determine adequate fuel cell-battery sizing (hybridization level) and the associated trends in the system efficiency.

Prefire identification for pulse-power systems

DOEpatents

Longmire, J.L.; Thuot, M.E.; Warren, D.S.

1982-08-23

Prefires in a high-power, high-frequency, multi-stage pulse generator are detected by a system having an EMI shielded pulse timing transmitter associated with and tailored to each stage of the pulse generator. Each pulse timing transmitter upon detection of a pulse triggers a laser diode to send an optical signal through a high frequency fiber optic cable to a pulse timing receiver which converts the optical signal to an electrical pulse. The electrical pulses from all pulse timing receivers are fed through an OR circuit to start a time interval measuring device and each electrical pulse is used to stop an individual channel in the measuring device thereby recording the firing sequence of the multi-stage pulse generator.

Prefire identification for pulse power systems

DOEpatents

Longmire, Jerry L.; Thuot, Michael E.; Warren, David S.

1985-01-01

Prefires in a high-power, high-frequency, multi-stage pulse generator are detected by a system having an EMI shielded pulse timing transmitter associated with and tailored to each stage of the pulse generator. Each pulse timing transmitter upon detection of a pulse triggers a laser diode to send an optical signal through a high frequency fiber optic cable to a pulse timing receiver which converts the optical signal to an electrical pulse. The electrical pulses from all pulse timing receivers are fed through an OR circuit to start a time interval measuring device and each electrical pulse is used to stop an individual channel in the measuring device thereby recording the firing sequence of the multi-stage pulse generator.

Optimization of power generating thermoelectric modules utilizing LNG cold energy

NASA Astrophysics Data System (ADS)

Jeong, Eun Soo

2017-12-01

A theoretical investigation to optimize thermoelectric modules, which convert LNG cold energy into electrical power, is performed using a novel one-dimensional analytic model. In the model the optimum thermoelement length and external load resistance, which maximize the energy conversion ratio, are determined by the heat supplied to the cold heat reservoir, the hot and cold side temperatures, the thermal and electrical contact resistances and the properties of thermoelectric materials. The effects of the thermal and electrical contact resistances and the heat supplied to the cold heat reservoir on the maximum energy conversion ratio, the optimum thermoelement length and the optimum external load resistance are shown.

Dynamic Modeling and Grid Interaction of a Tidal and River Generator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muljadi, Eduard; Gevorgian, Vahan; Donegan, James

This presentation provides a high-level overview of the deployment of a river generator installed in a small system. The turbine dynamics of a river generator, electrical generator, and power converter are modeled in detail. Various simulations can be exercised, and the impact of different control algorithms, failures of power switches, and corresponding impacts can be examined.

A thermally regenerative ammonia battery with carbon-silver electrodes for converting low-grade waste heat to electricity

NASA Astrophysics Data System (ADS)

Rahimi, Mohammad; Kim, Taeyoung; Gorski, Christopher A.; Logan, Bruce E.

2018-01-01

Thermally regenerative ammonia batteries (TRABs) have shown great promise as a method to convert low-grade waste heat into electrical power, with power densities an order of magnitude higher than other approaches. However, previous TRABs based on copper electrodes suffered from unbalanced anode dissolution and cathode deposition rates during discharging cycles, limiting practical applications. To produce a TRAB with stable and reversible electrode reactions over many cycles, inert carbon electrodes were used with silver salts. In continuous flow tests, power production was stable over 100 discharging cycles, demonstrating excellent reversibility. Power densities were 23 W m-2-electrode area in batch tests, which was 64% higher than that produced in parallel tests using copper electrodes, and 30 W m-2 (net energy density of 490 Wh m-3-anolyte) in continuous flow tests. While this battery requires the use a precious metal, an initial economic analysis of the system showed that the cost of the materials relative to energy production was 220 per MWh, which is competitive with energy production from other non-fossil fuel sources. A substantial reduction in costs could be obtained by developing less expensive anion exchange membranes.

Dynamics identification of a piezoelectric vibrational energy harvester by image analysis with a high speed camera

NASA Astrophysics Data System (ADS)

Wolszczak, Piotr; Łygas, Krystian; Litak, Grzegorz

2018-07-01

This study investigates dynamic responses of a nonlinear vibration energy harvester. The nonlinear mechanical resonator consists of a flexible beam moving like an inverted pendulum between amplitude limiters. It is coupled with a piezoelectric converter, and excited kinematically. Consequently, the mechanical energy input is converted into the electrical power output on the loading resistor included in an electric circuit attached to the piezoelectric electrodes. The curvature of beam mode shapes as well as deflection of the whole beam are examined using a high speed camera. The visual identification results are compared with the voltage output generated by the piezoelectric element for corresponding frequency sweeps and analyzed by the Hilbert transform.

47 CFR 22.99 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... converts radio frequency electrical energy to radiated electromagnetic energy and vice versa; in a... portion of the electromagnetic spectrum within which the emission power of the authorized transmitter(s.... The portion of the electromagnetic spectrum assigned by the FCC for one emission. In certain...

47 CFR 22.99 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... converts radio frequency electrical energy to radiated electromagnetic energy and vice versa; in a... portion of the electromagnetic spectrum within which the emission power of the authorized transmitter(s.... The portion of the electromagnetic spectrum assigned by the FCC for one emission. In certain...

47 CFR 22.99 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... converts radio frequency electrical energy to radiated electromagnetic energy and vice versa; in a... portion of the electromagnetic spectrum within which the emission power of the authorized transmitter(s.... The portion of the electromagnetic spectrum assigned by the FCC for one emission. In certain...

47 CFR 22.99 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... converts radio frequency electrical energy to radiated electromagnetic energy and vice versa; in a... portion of the electromagnetic spectrum within which the emission power of the authorized transmitter(s.... The portion of the electromagnetic spectrum assigned by the FCC for one emission. In certain...

47 CFR 22.99 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... converts radio frequency electrical energy to radiated electromagnetic energy and vice versa; in a... portion of the electromagnetic spectrum within which the emission power of the authorized transmitter(s.... The portion of the electromagnetic spectrum assigned by the FCC for one emission. In certain...

CAMP LEJEUNE ENERGY FROM WOOD (CLEW) PROJECT

EPA Science Inventory

The paper discusses EPA's Camp Lejeune Energy from Wood (CLEW) project, a demonstration project that converts wood energy to electric power, and provides waste utilization and pollution alleviation. The 1-MWe plant operates a reciprocating engine-generator set on synthetic gas f...

Use of a magnetic force exciter to vibrate a piezocomposite generating element in a small-scale windmill

NASA Astrophysics Data System (ADS)

Truyen Luong, Hung; Goo, Nam Seo

2012-02-01

A piezocomposite generating element (PCGE) can be used to convert ambient vibrations into electrical energy that can be stored and used to power other devices. This paper introduces a design of a magnetic force exciter for a small-scale windmill that vibrates a PCGE to convert wind energy into electrical energy. A small-scale windmill was designed to be sensitive to low-speed wind in urban regions for the purpose of collecting wind energy. The magnetic force exciter consists of exciting magnets attached to the device’s input rotor and a secondary magnet fixed at the tip of the PCGE. The PCGE is fixed to a clamp that can be adjusted to slide on the windmill’s frame in order to change the gap between exciting and secondary magnets. Under an applied wind force, the input rotor rotates to create a magnetic force interaction that excites the PCGE. The deformation of the PCGE enables it to generate electric power. Experiments were performed with different numbers of exciting magnets and different gaps between the exciting and secondary magnets to determine the optimal configuration for generating the peak voltage and harvesting the maximum wind energy for the same range of wind speeds. In a battery-charging test, the charging time for a 40 mA h battery was approximately 3 h for natural wind in an urban region. The experimental results show that the prototype can harvest energy in urban regions with low wind speeds and convert the wasted wind energy into electricity for city use.

Low power interface IC's for electrostatic energy harvesting applications

NASA Astrophysics Data System (ADS)

Kempitiya, Asantha

The application of wireless distributed micro-sensor systems ranges from equipment diagnostic and control to real time structural and biomedical monitoring. A major obstacle in developing autonomous micro-sensor networks is the need for local electric power supply, since using a battery is often not a viable solution. This void has sparked significant interest in micro-scale power generators based on electrostatic, piezoelectric and electromagnetic energy conversion that can scavenge ambient energy from the environment. In comparison to existing energy harvesting techniques, electrostatic-based power generation is attractive as it can be integrated using mainstream silicon technologies while providing higher power densities through miniaturization. However the power output of reported electrostatic micro-generators to date does not meet the communication and computation requirements of wireless sensor nodes. The objective of this thesis is to investigate novel CMOS-based energy harvesting circuit (EHC) architectures to increase the level of harvested mechanical energy in electrostatic converters. The electronic circuits that facilitate mechanical to electrical energy conversion employing variable capacitors can either have synchronous or asynchronous architectures. The later does not require synchronization of electrical events with mechanical motion, which eliminates difficulties in gate clocking and the power consumption associated with complex control circuitry. However, the implementation of the EHC with the converter can be detrimental to system performance when done without concurrent optimization of both elements, an aspect mainly overlooked in the literature. System level analysis is performed to show that there is an optimum value for either the storage capacitor or cycle number for maximum scavenging of ambient energy. The analysis also shows that maximum power is extracted when the system approaches synchronous operation. However, there is a region of interest where the storage capacitor can be optimized to produce almost 70% of the ideal power taken as the power harvested with synchronous converters when neglecting the power consumption associated with synchronizing control circuitry. Theoretical predictions are confirmed by measurements on an asynchronous EHC implemented with a macro-scale electrostatic converter prototype. Based on the preceding analysis, the design of a novel ultra low power electrostatic integrated energy harvesting circuit is proposed for efficient harvesting of mechanical energy. The fundamental challenges of designing reliable low power sensing circuits for charge constrained electrostatic energy harvesters with capacity to self power its controller and driver stages are addressed. Experimental results are presented for a controller design implemented in AMI 0.7muM high voltage CMOS process using a macro-scale electrostatic converter prototype. The EHC produces 1.126muW for a power investment of 417nW with combined conduction and controller losses of 450nW which is a 20-30% improvement compared to prior art on electrostatic EHCs operating under charge constrain. Inherently dual plate variable capacitors harvest energy only during half of the mechanical cycle with the other half unutilized for energy conversion. To harvest mechanical energy over the complete mechanical vibration cycle, a low power energy harvesting circuit (EHC) that performs charge constrained synchronous energy conversion on a tri-plate variable capacitor for maximizing energy conversion is proposed. The tri-plate macro electrostatic generator with capacitor variation of 405pF to 1.15nF and 405pF to 1.07nF on two complementary adjacent capacitors is fabricated and used in the characterization of the designed EHC. The integrated circuit fabricated in AMI 0.7muM high voltage CMOS process, produces a total output power of 497nW to a 10muF reservoir capacitor from a 98Hz vibration signal. In summary, the thesis lays out the theoretical and experimental foundation for overcoming the main challenges associated with the design of charge constrained synchronous EHC's, making electrostatic converters a possible candidate for powering emerging communication transceivers and portable electronics.

Thermal Expansion Studies of Selected High Temperature Thermoelectric Materials

NASA Technical Reports Server (NTRS)

Ravi, Vilupanur; Firdosy, Samad; Caillat, Thierry; Brandon, Erik; Van Der Walde, Keith; Maricic, Lina; Sayir, Ali

2008-01-01

Radioisotope thermoelectric generators (RTGs) generate electrical power by converting the heat released from the nuclear decay of radioactive isotopes (typically plutonium-238) into electricity using a thermoelectric converter. RTGs have been successfully used to power a number of space missions and have demonstrated their reliability over an extended period of time (tens of years) and are compact, rugged, radiation resistant, scalable, and produce no noise, vibration or torque during operation. System conversion efficiency for state-of-practice RTGs is about 6% and specific power less than or equal to 5.1 W/kg. Higher specific power would result in more on-board power for the same RTG mass, or less RTG mass for the same on-board power. The Jet Propulsion Laboratory has been leading, under the advanced thermoelectric converter (ATEC) project, the development of new high-temperature thermoelectric materials and components for integration into advanced, more efficient RTGs. Thermoelectric materials investigated to date include skutterudites, the Yb14MnSb11 compound, and SiGe alloys. The development of long-lived thermoelectric couples based on some of these materials has been initiated and is assisted by a thermo-mechanical stress analysis to ensure that all stresses under both fabrication and operation conditions will be within yield limits for those materials. Several physical parameters are needed as input to this analysis. Among those parameters, the coefficient of thermal expansion (CTE) is critically important. Thermal expansion coefficient measurements of several thermoelectric materials under consideration for ATEC are described in this paper. The stress response at the interfaces in material stacks subjected to changes in temperature is discussed, drawing on work from the literature and project-specific tools developed here. The degree of CTE mismatch and the associated effect on the formation of stress is highlighted.

A novel multimode hybrid energy storage system and its energy management strategy for electric vehicles

NASA Astrophysics Data System (ADS)

Wang, Bin; Xu, Jun; Cao, Binggang; Zhou, Xuan

2015-05-01

This paper proposes a novel topology of multimode hybrid energy storage system (HESS) and its energy management strategy for electric vehicles (EVs). Compared to the conventional HESS, the proposed multimode HESS has more operating modes and thus it could in further enhance the efficiency of the system. The rule-based control strategy and the power-balancing strategy are developed for the energy management strategy to realize mode selection and power distribution. Generally, the DC-DC converter will operate at peak efficiency to convey the energy from the batteries to the UCs. Otherwise, the pure battery mode or the pure ultracapacitors (UCs) mode will be utilized without the DC-DC converter. To extend the battery life, the UCs have the highest priority to recycle the energy and the batteries are isolated from being recharged directly during regenerative braking. Simulations and experiments are established to validate the proposed multimode HESS and its energy management strategy. The results reveal that the energy losses in the DC-DC converter, the total energy consumption and the overall system efficiency of the proposed multimode HESS are improved compared to the conventional HESS.

High Temperature Fusion Reactor Cooling Using Brayton Cycle Based Partial Energy Conversion

NASA Technical Reports Server (NTRS)

Juhasz, Albert J.; Sawicki, Jerzy T.

2003-01-01

For some future space power systems using high temperature nuclear heat sources most of the output energy will be used in other than electrical form, and only a fraction of the total thermal energy generated will need to be converted to electrical work. The paper describes the conceptual design of such a partial energy conversion system, consisting of a high temperature fusion reactor operating in series with a high temperature radiator and in parallel with dual closed cycle gas turbine (CCGT) power systems, also referred to as closed Brayton cycle (CBC) systems, which are supplied with a fraction of the reactor thermal energy for conversion to electric power. Most of the fusion reactor's output is in the form of charged plasma which is expanded through a magnetic nozzle of the interplanetary propulsion system. Reactor heat energy is ducted to the high temperature series radiator utilizing the electric power generated to drive a helium gas circulation fan. In addition to discussing the thermodynamic aspects of the system design the authors include a brief overview of the gas turbine and fan rotor-dynamics and proposed bearing support technology along with performance characteristics of the three phase AC electric power generator and fan drive motor.

High Temperature Fusion Reactor Cooling Using Brayton Cycle Based Partial Energy Conversion

NASA Astrophysics Data System (ADS)

Juhasz, Albert J.; Sawicki, Jerzy T.

2004-02-01

For some future space power systems using high temperature nuclear heat sources most of the output energy will be used in other than electrical form, and only a fraction of the total thermal energy generated will need to be converted to electrical work. The paper describes the conceptual design of such a ``partial energy conversion'' system, consisting of a high temperature fusion reactor operating in series with a high temperature radiator and in parallel with dual closed cycle gas turbine (CCGT) power systems, also referred to as closed Brayton cycle (CBC) systems, which are supplied with a fraction of the reactor thermal energy for conversion to electric power. Most of the fusion reactor's output is in the form of charged plasma which is expanded through a magnetic nozzle of the interplanetary propulsion system. Reactor heat energy is ducted to the high temperature series radiator utilizing the electric power generated to drive a helium gas circulation fan. In addition to discussing the thermodynamic aspects of the system design the authors include a brief overview of the gas turbine and fan rotor-dynamics and proposed bearing support technology along with performance characteristics of the three phase AC electric power generator and fan drive motor.

Transient stability enhancement of wind farms using power electronics and facts controllers

NASA Astrophysics Data System (ADS)

Mohammadpour, Hossein Ali

Nowadays, it is well-understood that the burning of fossil fuels in electric power station has a significant influence on the global climate due to greenhouse gases. In many countries, the use of cost-effective and reliable low-carbon electricity energy sources is becoming an important energy policy. Among different kinds of clean energy resources- such as solar power, hydro-power, ocean wave power and so on, wind power is the fastest-growing form of renewable energy at the present time. Moreover, adjustable speed generator wind turbines (ASGWT) has key advantages over the fixed-speed generator wind turbines (FSGWT) in terms of less mechanical stress, improved power quality, high system efficiency, and reduced acoustic noise. One important class of ASGWT is the doubly-fed induction generator (DFIG), which has gained a significant attention of the electric power industry due to their advantages over the other class of ASGWT, i.e. fully rated converter-based wind turbines. Because of increased integration of DFIG-based wind farms into electric power grids, it is necessary to transmit the generated power from wind farms to the existing grids via transmission networks without congestion. Series capacitive compensation of DFIG-based wind farm is an economical way to increase the power transfer capability of the transmission line connecting wind farm to the grid. For example, a study performed by ABB reveals that increasing the power transfer capability of an existing transmission line from 1300 MW to 2000 MW using series compensation is 90% less than the cost of building a new transmission line. However, a factor hindering the extensive use of series capacitive compensation is the potential risk of sub- synchronous resonance (SSR). The SSR is a condition where the wind farm exchanges energy with the electric network, to which it is connected, at one or more natural frequencies of the electric or mechanical part of the combined system, comprising the wind farm and the network, and the frequency of the exchanged energy is below the fundamental frequency of the system. This phenomenon may cause severe damage in the wind farm, if not prevented. Therefore, this dissertation deals with the SSR phenomena in a capacitive series compensated wind farm. A DFIG-based wind farm, which is connected to a series compensated transmission line, is considered as a case study. The small-signal stability analysis of the system is presented, and the eigenvalues of the system are obtained. Using both modal analysis and time-domain simulation, it is shown that the system is potentially unstable due to the SSR mode. Then, three different possibilities for the addition of SSR damping controller (SSRDC) are investigated. The SSRDC can be added to (1) gate-controlled series capacitor (GCSC), (2) thyristor-controlled series capacitor (TCSC), or (3) DFIG rotor-side converter (RSC) and grid-side converter (GSC) controllers. The first and second cases are related to the series flexible AC transmission systems (FACTS) family, and the third case uses the DFIG back-to-back converters to damp the SSR. The SSRDC is designed using residue-based analysis and root locus diagrams. Using residue-based analysis, the optimal input control signal (ICS) to the SSRDC is identified that can damp the SSR mode without destabilizing other modes, and using root-locus analysis, the required gain for the SSRDC is determined. Moreover, two methods are discussed in order to estimate the optimum input signal to the SSRDC, without measuring it directly. In this dissertation, MATLAB/Simulink is used as a tool for modeling and design of the SSRDC, and PSCAD/EMTDC is used to perform time-domain simulation in order to verify the design process.

Nuclear Power in Space

DOE R&D Accomplishments Database

1994-01-01

In the early years of the United States space program, lightweight batteries, fuel cells, and solar modules provided electric power for space missions. As missions became more ambitious and complex, power needs increased and scientists investigated various options to meet these challenging power requirements. One of the options was nuclear energy. By the mid-1950s, research had begun in earnest on ways to use nuclear power in space. These efforts resulted in the first radioisotope thermoelectric generators (RTGs), which are nuclear power generators build specifically for space and special terrestrial uses. These RTGs convert the heat generated from the natural decay of their radioactive fuel into electricity. RTGs have powered many spacecraft used for exploring the outer planets of the solar system and orbiting the sun and Earth. They have also landed on Mars and the moon. They provide the power that enables us to see and learn about even the farthermost objects in our solar system.

Analyzing Carbohydrate-Based Regenerative Fuel Cells as a Power Source for Unmanned Aerial Vehicles

DTIC Science & Technology

2008-03-01

conventional means of generating electrical energy, such as turbines and internal combustion engines, in that the conventional methods normally have an...have 24 hours of daylight, this means that it must be able to store enough exergy (the total amount of energy that can theoretically be converted to...useful work, differentiated from useful energy by the efficiency of converting energy to work) to function during the time when exergy consumption is

Second NASA Conference on Laser Energy Conversion

NASA Technical Reports Server (NTRS)

Billman, K. W. (Editor)

1976-01-01

The possible transmission of high power laser beams over long distances and their conversion to thrust, electricity, or other useful forms of energy is considered. Specific topics discussed include: laser induced chemistry; developments in photovoltaics, including modification of the Schottky barrier devices and generation of high voltage emf'sby laser radiation of piezoelectric ceramics; the thermo electronic laser energy converter and the laser plasmadynamics converters; harmonic conversion of infrared laser radiation in molecular gases; and photon engines.

Power system applications of fiber optic sensors

NASA Technical Reports Server (NTRS)

Johnston, A. R.; Jackson, S. P.; Kirkham, H.; Yeh, C.

1986-01-01

This document is a progress report of work done in 1985 on the Communications and Control for Electric Power Systems Project at the Jet Propulsion Laboratory. These topics are covered: Electric Field Measurement, Fiber Optic Temperature Sensing, and Optical Power transfer. Work was done on the measurement of ac and dc electric fields. A prototype sensor for measuring alternating fields was made using a very simple electroscope approach. An electronic field mill sensor for dc fields was made using a fiber optic readout, so that the entire probe could be operated isolated from ground. There are several instances in which more precise knowledge of the temperature of electrical power apparatus would be useful. This report describes a number of methods whereby the distributed temperature profile can be obtained using a fiber optic sensor. The ability to energize electronics by means of an optical fiber has the advantage that electrical isolation is maintained at low cost. In order to accomplish this, it is necessary to convert the light energy into electrical form by means of photovoltaic cells. JPL has developed an array of PV cells in gallium arsenide specifically for this purpose. This work is described.

Stability of large DC power systems using switching converters, with application to the international space station

NASA Technical Reports Server (NTRS)

Manners, B.; Gholdston, E. W.; Karimi, K.; Lee, F. C.; Rajagopalan, J.; Panov, Y.

1996-01-01

As space direct current (dc) power systems continue to grow in size, switching power converters are playing an ever larger role in power conditioning and control. When designing a large dc system using power converters of this type, special attention must be placed on the electrical stability of the system and of the individual loads on the system. In the design of the electric power system (EPS) of the International Space Station (ISS), the National Aeronautics and Space Administration (NASA) and its contractor team led by Boeing Defense & Space Group has placed a great deal of emphasis on designing for system and load stability. To achieve this goal, the team has expended considerable effort deriving a dear concept on defining system stability in both a general sense and specifically with respect to the space station. The ISS power system presents numerous challenges with respect to system stability, such as high power, complex sources and undefined loads. To complicate these issues, source and load components have been designed in parallel by three major subcontractors (Boeing, Rocketdyne, and McDonnell Douglas) with interfaces to both sources and loads being designed in different countries (Russia, Japan, Canada, Europe, etc.). These issues, coupled with the program goal of limiting costs, have proven a significant challenge to the program. As a result, the program has derived an impedance specification approach for system stability. This approach is based on the significant relationship between source and load impedances and the effect of this relationship on system stability. This approach is limited in its applicability by the theoretical and practical limits on component designs as presented by each system segment. As a result, the overall approach to system stability implemented by the ISS program consists of specific hardware requirements coupled with extensive system analysis and hardware testing. Following this approach, the ISS program plans to begin construction of the world's largest orbiting power system in 1997.

Magnetic characterization of the stator core of a high-speed motor made of an ultrathin electrical steel sheet using the magnetic property evaluation system

NASA Astrophysics Data System (ADS)

Oka, Mohachiro; Enokizono, Masato; Mori, Yuji; Yamazaki, Kazumasa

2018-04-01

Recently, the application areas for electric motors have been expanding. For instance, electric motors are used in new technologies such as rovers, drones, cars, and robots. The motor used in such machinery should be small, high-powered, highly-efficient, and high-speed. In such motors, loss at high-speed rotation must be especially minimal. Eddy-current loss in the stator core is known to increase greatly during loss at high-speed rotation of the motor. To produce an efficient high-speed motor, we are developing a stator core for a motor using an ultrathin electrical steel sheet with only a small amount of eddy-current loss. Furthermore, the magnetic property evaluation for efficient, high-speed motor stator cores that use conventional commercial frequency is insufficient. Thus, we made a new high-speed magnetic property evaluation system to evaluate the magnetic properties of the efficient high-speed motor stator core. This system was composed of high-speed A/D converters, D/A converters, and a high-speed power amplifier. In experiments, the ultrathin electrical steel sheet dramatically suppressed iron loss and, in particular, eddy-current loss. In addition, a new high-speed magnetic property evaluation system accurately evaluated the magnetic properties of the efficient high-speed motor stator core.

A review of test results on solar thermal power modules with dish-mounted Stirling and Brayton cycle engines

NASA Technical Reports Server (NTRS)

Jaffe, Leonard D.

1988-01-01

This paper presents results of development tests of various solar thermal parabolic dish modules and assemblies that used dish-mounted Brayton or Stirling cycle engines for production of electric power. These tests indicate that early modules achieve net efficiencies up to 29 percent in converting sunlight to electricity, as delivered to the grid. Various equipment deficiencies were observed and a number of malfunctions occurred. The performance measurements, as well as the malfunctions and other test experience, provided information that should be of value in developing systems with improved performance and reduced maintenance.

Gallium phosphide energy converters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sims, P.E.; Dinetta, L.C.; Goetz, M.A.

1995-10-01

Gallium phosphide (GaP) energy converters may be successfully deployed to provide new mission capabilities for spacecraft. Betavoltaic power supplies based on the conversion of tritium beta decay to electricity using GaP energy converters can supply long term low-level power with high reliability. High temperature solar cells, also based on GaP, can be used in inward-bound missions greatly reducing the need for thermal dissipation. Results are presented for GaP direct conversion devices powered by Ni-63 and compared to the conversion of light emitted by tritiarated phosphors. Leakage currents as low as 1.2 x 10(exp {minus}17) A/sq cm have been measured andmore » the temperature dependence of the reverse saturation current is found to have ideal behavior. Temperature dependent IV, QE, R(sub sh), and V(sub oc) results are also presented. These data are used to predict the high-temperature solar cell and betacell performance of GaP devices and suggest appropriate applications for the deployment of this technology.« less

Gallium phosphide energy converters

NASA Astrophysics Data System (ADS)

Sims, P. E.; Dinetta, L. C.; Goetz, M. A.

1995-10-01

Gallium phosphide (GaP) energy converters may be successfully deployed to provide new mission capabilities for spacecraft. Betavoltaic power supplies based on the conversion of tritium beta decay to electricity using GaP energy converters can supply long term low-level power with high reliability. High temperature solar cells, also based on GaP, can be used in inward-bound missions greatly reducing the need for thermal dissipation. Results are presented for GaP direct conversion devices powered by Ni-63 and compared to the conversion of light emitted by tritiarated phosphors. Leakage currents as low as 1.2 x 10(exp -17) A/sq cm have been measured and the temperature dependence of the reverse saturation current is found to have ideal behavior. Temperature dependent IV, QE, R(sub sh), and V(sub oc) results are also presented. These data are used to predict the high-temperature solar cell and betacell performance of GaP devices and suggest appropriate applications for the deployment of this technology.

Gallium phosphide energy converters

NASA Technical Reports Server (NTRS)

Sims, P. E.; Dinetta, L. C.; Goetz, M. A.

1995-01-01

Gallium phosphide (GaP) energy converters may be successfully deployed to provide new mission capabilities for spacecraft. Betavoltaic power supplies based on the conversion of tritium beta decay to electricity using GaP energy converters can supply long term low-level power with high reliability. High temperature solar cells, also based on GaP, can be used in inward-bound missions greatly reducing the need for thermal dissipation. Results are presented for GaP direct conversion devices powered by Ni-63 and compared to the conversion of light emitted by tritiarated phosphors. Leakage currents as low as 1.2 x 10(exp -17) A/sq cm have been measured and the temperature dependence of the reverse saturation current is found to have ideal behavior. Temperature dependent IV, QE, R(sub sh), and V(sub oc) results are also presented. These data are used to predict the high-temperature solar cell and betacell performance of GaP devices and suggest appropriate applications for the deployment of this technology.

Bidirectional control system for energy flow in solar powered flywheel

NASA Technical Reports Server (NTRS)

Nola, Frank J. (Inventor)

1987-01-01

An energy storage system for a spacecraft is provided which employs a solar powered flywheel arrangement including a motor/generator which, in different operating modes, drives the flywheel and is driven thereby. A control circuit, including a threshold comparator, senses the output of a solar energy converter, and when a threshold voltage is exceeded thereby indicating the availability of solar power for the spacecraft loads, activates a speed control loop including the motor/generator so as to accelerate the flywheel to a constant speed and thereby store mechanical energy, while also supplying energy from the solar converter to the loads. Under circumstances where solar energy is not available and thus the threshold voltage is not exceeded, the control circuit deactivates the speed control loop and activates a voltage control loop that provides for operation of the motor as a generator so that mechanical energy from the flywheel is converted into electrical energy for supply to the spacecraft loads.

A new model predictive control algorithm by reducing the computing time of cost function minimization for NPC inverter in three-phase power grids.

PubMed

Taheri, Asghar; Zhalebaghi, Mohammad Hadi

2017-11-01

This paper presents a new control strategy based on finite-control-set model-predictive control (FCS-MPC) for Neutral-point-clamped (NPC) three-level converters. Containing some advantages like fast dynamic response, easy inclusion of constraints and simple control loop, makes the FCS-MPC method attractive to use as a switching strategy for converters. However, the large amount of required calculations is a problem in the widespread of this method. In this way, to resolve this problem this paper presents a modified method that effectively reduces the computation load compare with conventional FCS-MPC method and at the same time does not affect on control performance. The proposed method can be used for exchanging power between electrical grid and DC resources by providing active and reactive power compensations. Experiments on three-level converter for three Power Factor Correction (PFC), inductive and capacitive compensation modes verify the good and comparable performance. The results have been simulated using MATLAB/SIMULINK software. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

A Particle-in-Cell Simulation for the Traveling Wave Direct Energy Converter (TWDEC) for Fusion Propulsion

NASA Technical Reports Server (NTRS)

Chap, Andrew; Tarditi, Alfonso G.; Scott, John H.

2013-01-01

A Particle-in-cell simulation model has been developed to study the physics of the Traveling Wave Direct Energy Converter (TWDEC) applied to the conversion of charged fusion products into electricity. In this model the availability of a beam of collimated fusion products is assumed; the simulation is focused on the conversion of the beam kinetic energy into alternating current (AC) electric power. The model is electrostatic, as the electro-dynamics of the relatively slow ions can be treated in the quasistatic approximation. A two-dimensional, axisymmetric (radial-axial coordinates) geometry is considered. Ion beam particles are injected on one end and travel along the axis through ring-shaped electrodes with externally applied time-varying voltages, thus modulating the beam by forming a sinusoidal pattern in the beam density. Further downstream, the modulated beam passes through another set of ring electrodes, now electrically oating. The modulated beam induces a time alternating potential di erence between adjacent electrodes. Power can be drawn from the electrodes by connecting a resistive load. As energy is dissipated in the load, a corresponding drop in beam energy is measured. The simulation encapsulates the TWDEC process by reproducing the time-dependent transfer of energy and the particle deceleration due to the electric eld phase time variations.

An integral nuclear power and propulsion system concept

NASA Astrophysics Data System (ADS)

Choong, Phillip T.; Teofilo, Vincent L.; Begg, Lester L.; Dunn, Charles; Otting, William

An integral space power concept provides both the electrical power and propulsion from a common heat source and offers superior performance capabilities over conventional orbital insertion using chemical propulsion systems. This paper describes a hybrid (bimodal) system concept based on a proven, inherently safe solid fuel form for the high temperature reactor core operation and rugged planar thermionic energy converter for long-life steady state electric power production combined with NERVA-based rocket technology for propulsion. The integral system is capable of long-life power operation and multiple propulsion operations. At an optimal thrust level, the integral system can maintain the minimal delta-V requirement while minimizing the orbital transfer time. A trade study comparing the overall benefits in placing large payloads to GEO with the nuclear electric propulsion option shows superiority of nuclear thermal propulsion. The resulting savings in orbital transfer time and the substantial reduction of overall lift requirement enables the use of low-cost launchers for several near-term military satellite missions.

Wind Velocity and Position Sensor-less Operation for PMSG Wind Generator

NASA Astrophysics Data System (ADS)

Senjyu, Tomonobu; Tamaki, Satoshi; Urasaki, Naomitsu; Uezato, Katsumi; Funabashi, Toshihisa; Fujita, Hideki

Electric power generation using non-conventional sources is receiving considerable attention throughout the world. Wind energy is one of the available non-conventional energy sources. Electrical power generation using wind energy is possible in two ways, viz. constant speed operation and variable speed operation using power electronic converters. Variable speed power generation is attractive, because maximum electric power can be generated at all wind velocities. However, this system requires a rotor speed sensor, for vector control purpose, which increases the cost of the system. To alleviate the need of rotor speed sensor in vector control, we propose a new sensor-less control of PMSG (Permanent Magnet Synchronous Generator) based on the flux linkage. We can estimate the rotor position using the estimated flux linkage. We use a first-order lag compensator to obtain the flux linkage. Furthermore‚we estimate wind velocity and rotation speed using a observer. The effectiveness of the proposed method is demonstrated thorough simulation results.

Satellite Power System (SPS) microwave subsystem impacts and benefits

NASA Technical Reports Server (NTRS)

Dickinson, R. M.

1977-01-01

The impacts and benefits to society of the microwave subsystem resulting from the developing, construction and operating of a space solar power to earth, electric power delivery system are presented and discussed. The primary benefit (usable energy) is conveyed mainly in the fundamental frequency portion of the RF radiation beam that is intercepted and converted to electric power output. The small fraction of the microwave and other electromagnetic energy that does not end up in the electric utility grid, yields most of the subsystem impacts. The impacts range from harmonics and noise radiated by the transmitting antenna, through potential interference with ionospheric communications and navigation caused by the power beam heating the ionosphere, to the potential large land area requirements for the rectennas and low level microwave radiation around the rectennas. Additional benefits range from a very low level of waste heat liberated and lack of atmospheric emissions including noise while operating to having no residual ionizing radiation from the rectenna when it is deactivated.

Aiding Design of Wave Energy Converters via Computational Simulations

NASA Astrophysics Data System (ADS)

Jebeli Aqdam, Hejar; Ahmadi, Babak; Raessi, Mehdi; Tootkaboni, Mazdak

2015-11-01

With the increasing interest in renewable energy sources, wave energy converters will continue to gain attention as a viable alternative to current electricity production methods. It is therefore crucial to develop computational tools for the design and analysis of wave energy converters. A successful design requires balance between the design performance and cost. Here an analytical solution is used for the approximate analysis of interactions between a flap-type wave energy converter (WEC) and waves. The method is verified using other flow solvers and experimental test cases. Then the model is used in conjunction with a powerful heuristic optimization engine, Charged System Search (CSS) to explore the WEC design space. CSS is inspired by charged particles behavior. It searches the design space by considering candidate answers as charged particles and moving them based on the Coulomb's laws of electrostatics and Newton's laws of motion to find the global optimum. Finally the impacts of changes in different design parameters on the power takeout of the superior WEC designs are investigated. National Science Foundation, CBET-1236462.

On-Shore Central Hydraulic Power Generation for Wind and Tidal Energy

NASA Technical Reports Server (NTRS)

Jones, Jack A.; Bruce, Allan; Lim, Steven; Murray, Luke; Armstrong, Richard; Kimbrall, Richard; Cook-Chenault, Kimberly; DeGennaro, Sean

2012-01-01

Tidal energy, offshore wind energy, and onshore wind energy can be converted to electricity at a central ground location by means of converting their respective energies into high-pressure hydraulic flows that are transmitted to a system of generators by high-pressure pipelines. The high-pressure flows are then efficiently converted to electricity by a central power plant, and the low-pressure outlet flow is returned. The Department of Energy (DOE) is presently supporting a project led by Sunlight Photonics to demonstrate a 15 kW tidal hydraulic power generation system in the laboratory and possibly later submerged in the ocean. All gears and submerged electronics are completely eliminated. A second portion of this DOE project involves sizing and costing a 15 MW tidal energy system for a commercial tidal energy plant. For this task, Atlantis Resources Corporation s 18-m diameter demonstrated tidal blades are rated to operate in a nominal 2.6 m/sec tidal flow to produce approximately one MW per set of tidal blades. Fifteen units would be submerged in a deep tidal area, such as in Maine s Western Passage. All would be connected to a high-pressure (20 MPa, 2900 psi) line that is 35 cm ID. The high-pressure HEPG fluid flow is transported 500-m to on-shore hydraulic generators. HEPG is an environmentally-friendly, biodegradable, watermiscible fluid. Hydraulic adaptations to ORPC s cross-flow turbines are also discussed. For 15 MW of wind energy that is onshore or offshore, a gearless, high efficiency, radial piston pump can replace each set of top-mounted gear-generators. The fluid is then pumped to a central, easily serviceable generator location. Total hydraulic/electrical efficiency is 0.81 at full rated wind or tidal velocities and increases to 0.86 at 1/3 rated velocities.

On-Shore Central Hydraulic Power Generation for Wind and Tidal Energy

NASA Technical Reports Server (NTRS)

Jones, Jack A.; Bruce, Allan; Lim, Steven; Murray, Luke; Armstrong, Richard; Kimball, Richard; Cook-Chenault, Kimberly; DeGennaro, Sean

2012-01-01

Tidal energy, offshore wind energy, and onshore wind energy can be converted to electricity at a central ground location by means of converting their respective energies into high-pressure hydraulic flows that are transmitted to a system of generators by high-pressure pipelines. The high-pressure flows are then efficiently converted to electricity by a central power plant, and the low-pressure outlet flow is returned. The Department of Energy (DOE) is presently supporting a project led by Sunlight Photonics to demonstrate a 15 kilowatt tidal hydraulic power generation system in the laboratory and possibly later submerged in the ocean. All gears and submerged electronics are completely eliminated.A second portion of this DOE project involves sizing and costing a 15 megawatt tidal energy system for a commercial tidal energy plant. For this task, Atlantis Resources Corporation's 18-m diameter demonstrated tidal blades are rated to operate in a nominal 2.6 m/sec tidal flow to produce approximately one megawatt per set of tidal blades. Fifteen units would be submerged in a deep tidal area, such as in Maine's Western Passage. All would be connected to a high-pressure (20 megapascals, 2900 pounds per square inch) line that is 35 cm ID. The high-pressure HEPG fluid flow is transported 500-m to on-shore hydraulic generators. HEPG is an environmentally-friendly, biodegradable, water-miscible fluid. Hydraulic adaptations to ORPC's cross-flow turbines are also discussed.For 15 megawatt of wind energy that is onshore or offshore, a gearless, high efficiency, radial piston pump can replace each set of top-mounted gear-generators. The fluid is then pumped to a central, easily serviceable generator location. Total hydraulic/electrical efficiency is 0.81 at full rated wind or tidal velocities and increases to 0.86 at 1/3 rated velocities.

High power density yeast catalyzed microbial fuel cells

NASA Astrophysics Data System (ADS)

Ganguli, Rahul

Microbial fuel cells leverage whole cell biocatalysis to convert the energy stored in energy-rich renewable biomolecules such as sugar, directly to electrical energy at high efficiencies. Advantages of the process include ambient temperature operation, operation in natural streams such as wastewater without the need to clean electrodes, minimal balance-of-plant requirements compared to conventional fuel cells, and environmentally friendly operation. These make the technology very attractive as portable power sources and waste-to-energy converters. The principal problem facing the technology is the low power densities compared to other conventional portable power sources such as batteries and traditional fuel cells. In this work we examined the yeast catalyzed microbial fuel cell and developed methods to increase the power density from such fuel cells. A combination of cyclic voltammetry and optical absorption measurements were used to establish significant adsorption of electron mediators by the microbes. Mediator adsorption was demonstrated to be an important limitation in achieving high power densities in yeast-catalyzed microbial fuel cells. Specifically, the power densities are low for the length of time mediator adsorption continues to occur. Once the mediator adsorption stops, the power densities increase. Rotating disk chronoamperometry was used to extract reaction rate information, and a simple kinetic expression was developed for the current observed in the anodic half-cell. Since the rate expression showed that the current was directly related to microbe concentration close to the electrode, methods to increase cell mass attached to the anode was investigated. Electrically biased electrodes were demonstrated to develop biofilm-like layers of the Baker's yeast with a high concentration of cells directly connected to the electrode. The increased cell mass did increase the power density 2 times compared to a non biofilm fuel cell, but the power density increase was shown to quickly saturate with cell mass attached on the electrode. Based on recent modelling data that suggested that the electrode currents might be limited by the poor electrical conductivity of the anode, the power density versus electrical conductivity of a yeast-immobilized anode was investigated. Introduction of high aspect ratio carbon fiber filaments to the immobilization matrix increased the electrical conductivity of the anode. Although a higher electrical conductivity clearly led to an increase in power densities, it was shown that the principal limitation to power density increase was coming from proton transfer limitations in the immobilized anode. Partial overcoming of the gradients lead a power density of ca. 250 microW cm-2, which is the highest reported for yeast powered MFCs. A yeast-catalyzed microbial fuel cell was investigated as a power source for low power sensors using raw tree sap. It was shown that yeast can efficiently utilize the sucrose present in the raw tree sap to produce electricity when excess salt is added to the medium. Therefore the salinity of a potential energy source is an important consideration when MFCs are being considered for energy harvesting from natural sources.

Experimental investigation into the fault response of superconducting hybrid electric propulsion electrical power system to a DC rail to rail fault

NASA Astrophysics Data System (ADS)

Nolan, S.; Jones, C. E.; Munro, R.; Norman, P.; Galloway, S.; Venturumilli, S.; Sheng, J.; Yuan, W.

2017-12-01

Hybrid electric propulsion aircraft are proposed to improve overall aircraft efficiency, enabling future rising demands for air travel to be met. The development of appropriate electrical power systems to provide thrust for the aircraft is a significant challenge due to the much higher required power generation capacity levels and complexity of the aero-electrical power systems (AEPS). The efficiency and weight of the AEPS is critical to ensure that the benefits of hybrid propulsion are not mitigated by the electrical power train. Hence it is proposed that for larger aircraft (~200 passengers) superconducting power systems are used to meet target power densities. Central to the design of the hybrid propulsion AEPS is a robust and reliable electrical protection and fault management system. It is known from previous studies that the choice of protection system may have a significant impact on the overall efficiency of the AEPS. Hence an informed design process which considers the key trades between choice of cable and protection requirements is needed. To date the fault response of a voltage source converter interfaced DC link rail to rail fault in a superconducting power system has only been investigated using simulation models validated by theoretical values from the literature. This paper will present the experimentally obtained fault response for a variety of different types of superconducting tape for a rail to rail DC fault. The paper will then use these as a platform to identify key trades between protection requirements and cable design, providing guidelines to enable future informed decisions to optimise hybrid propulsion electrical power system and protection design.

Magnetic Frequency Response of HL-LHC Beam Screens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morrone, M.; Martino, M.; De Maria, R.

Magnetic fields used to control particle beams in accelerators are usually controlled by regulating the electrical current of the power converters. In order to minimize lifetime degradation and ultimately luminosity loss in circular colliders, current-noise is a highly critical figure of merit of power converters, in particular for magnets located in areas with high beta-function, like the High Luminosity Large Hadron Collider (HL-LHC) insertions. However, what is directly acting upon the beam is the magnetic field and not the current of the power converter, which undergoes several frequency-dependent transformations until the desired magnetic field, seen by the beam, is obtained.more » Beam screens are very rarely considered when assessing or specifying the noise figure of merit, but their magnetic frequency response is such that they realize relatively effective low pass filtering of the magnetic field produced by the system magnet-power converter. This work aims at filling this gap by quantifying the expected impact of different beam screen layouts for the most relevant HL-LHC insertion magnets. A welldefined post-processing technique is used to derive the frequency response of the different multipoles from multi-physics Finite Element Method (FEM) simulation results. In addition, a well approximated analytical formula for the low-frequency range of multi-layered beam screens is presented.« less

A Closed Brayton Power Conversion Unit Concept for Nuclear Electric Propulsion for Deep Space Missions

NASA Astrophysics Data System (ADS)

Joyner, Claude Russell; Fowler, Bruce; Matthews, John

2003-01-01

In space, whether in a stable satellite orbit around a planetary body or traveling as a deep space exploration craft, power is just as important as the propulsion. The need for power is especially important for in-space vehicles that use Electric Propulsion. Using nuclear power with electric propulsion has the potential to provide increased payload fractions and reduced mission times to the outer planets. One of the critical engineering and design aspects of nuclear electric propulsion at required mission optimized power levels is the mechanism that is used to convert the thermal energy of the reactor to electrical power. The use of closed Brayton cycles has been studied over the past 30 or years and shown to be the optimum approach for power requirements that range from ten to hundreds of kilowatts of power. It also has been found to be scalable to higher power levels. The Closed Brayton Cycle (CBC) engine power conversion unit (PCU) is the most flexible for a wide range of power conversion needs and uses state-of-the-art, demonstrated engineering approaches. It also is in use with many commercial power plants today. The long life requirements and need for uninterrupted operation for nuclear electric propulsion demands high reliability from a CBC engine. A CBC engine design for use with a Nuclear Electric Propulsion (NEP) system has been defined based on Pratt & Whitney's data from designing long-life turbo-machines such as the Space Shuttle turbopumps and military gas turbines and the use of proven integrated control/health management systems (EHMS). An integrated CBC and EHMS design that is focused on using low-risk and proven technologies will over come many of the life-related design issues. This paper will discuss the use of a CBC engine as the power conversion unit coupled to a gas-cooled nuclear reactor and the design trends relative to its use for powering electric thrusters in the 25 kWe to 100kWe power level.

Advanced Integrated Traction System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greg Smith; Charles Gough

2011-08-31

The United States Department of Energy elaborates the compelling need for a commercialized competitively priced electric traction drive system to proliferate the acceptance of HEVs, PHEVs, and FCVs in the market. The desired end result is a technically and commercially verified integrated ETS (Electric Traction System) product design that can be manufactured and distributed through a broad network of competitive suppliers to all auto manufacturers. The objectives of this FCVT program are to develop advanced technologies for an integrated ETS capable of 55kW peak power for 18 seconds and 30kW of continuous power. Additionally, to accommodate a variety of automotivemore » platforms the ETS design should be scalable to 120kW peak power for 18 seconds and 65kW of continuous power. The ETS (exclusive of the DC/DC Converter) is to cost no more than $660 (55kW at $12/kW) to produce in quantities of 100,000 units per year, should have a total weight less than 46kg, and have a volume less than 16 liters. The cost target for the optional Bi-Directional DC/DC Converter is $375. The goal is to achieve these targets with the use of engine coolant at a nominal temperature of 105C. The system efficiency should exceed 90% at 20% of rated torque over 10% to 100% of maximum speed. The nominal operating system voltage is to be 325V, with consideration for higher voltages. This project investigated a wide range of technologies, including ETS topologies, components, and interconnects. Each technology and its validity for automotive use were verified and then these technologies were integrated into a high temperature ETS design that would support a wide variety of applications (fuel cell, hybrids, electrics, and plug-ins). This ETS met all the DOE 2010 objectives of cost, weight, volume and efficiency, and the specific power and power density 2015 objectives. Additionally a bi-directional converter was developed that provides charging and electric power take-off which is the first step towards enabling a smart-grid application. GM under this work assessed 29 technologies; investigated 36 configurations/types power electronics and electric machines, filed 41 invention disclosures; and ensured technology compatibility with vehicle production. Besides the development of a high temperature ETS the development of industrial suppliers took place because of this project. Suppliers of industrial power electronic components are numerous, but there are few that have traction drive knowledge. This makes it difficult to achieve component reliability, durability, and cost requirements necessary of high volume automotive production. The commercialization of electric traction systems for automotive industry requires a strong diverse supplier base. Developing this supplier base is dependent on a close working relationship between the OEM and supplier so that appropriate component requirements can be developed. GM has worked closely with suppliers to develop components for electric traction systems. Components that have been the focus of this project are power modules, capacitors, heavy copper boards, current sensors, and gate drive and controller chip sets. Working with suppliers, detailed component specifications have been developed. Current, voltage, and operation environment during the vehicle drive cycle were evaluated to develop higher resolution/accurate component specifications.« less

The alkali metal thermoelectric converter /AMTEC/ - A new direct energy conversion technology for aerospace power

NASA Technical Reports Server (NTRS)

Bankston, C. P.; Cole, T.; Jones, R.; Ewell, R.

1982-01-01

A thermally regenerative electrochemical device for the direct conversion of heat to electrical energy, the alkali metal thermoelectric converter (AMTEC), is characterized by potential efficiencies on the order of 15-40% and possesses no moving parts, making it a candidate for space power system applications. Device conversion efficiency is projected on the basis of experimental voltage vs current curves exhibiting power densities of 0.7 W/sq cm and measured electrode efficiencies of up to 40%. Preliminary radiative heat transfer measurements presented may be used in an investigation of methods for the reduction of AMTEC parasitic radiation losses. AMTEC assumes heat input and rejection temperatures of 900-1300 K and 400-800 K, respectively. The working fluid is liquid sodium, and the porous electrode employed is of molybdenum.

Power Cycle Testing of Power Switches: A Literature Survey

DOE Office of Scientific and Technical Information (OSTI.GOV)

GopiReddy, Lakshmi Reddy; Tolbert, Leon M.; Ozpineci, Burak

Reliability of power converters and lifetime prediction has been a major topic of research in the last few decades, especially for traction applications. The main failures in high power semiconductors are caused by thermomechanical fatigue. Power cycling and temperature cycling are the two most common thermal acceleration tests used in assessing reliability. The objective of this paper is to study the various power cycling tests found in the literature and to develop generalized steps in planning application specific power cycling tests. A comparison of different tests based on the failures, duration, test circuits, and monitored electrical parameters is presented.

Power Cycle Testing of Power Switches: A Literature Survey

DOE PAGES

GopiReddy, Lakshmi Reddy; Tolbert, Leon M.; Ozpineci, Burak

2014-09-18

Reliability of power converters and lifetime prediction has been a major topic of research in the last few decades, especially for traction applications. The main failures in high power semiconductors are caused by thermomechanical fatigue. Power cycling and temperature cycling are the two most common thermal acceleration tests used in assessing reliability. The objective of this paper is to study the various power cycling tests found in the literature and to develop generalized steps in planning application specific power cycling tests. A comparison of different tests based on the failures, duration, test circuits, and monitored electrical parameters is presented.

Gallium phosphide energy converters

NASA Technical Reports Server (NTRS)

Sims, P. E.; DiNetta, Louis C.; DuganCavanagh, K.; Goetz, M. A.

1996-01-01

Betavoltaic power supplies based on gallium phosphide can supply long term low-level power with high reliability. Results are presented for GaP devices powered by Ni-63 and tritiarated phosphors. Leakage currents as low as 1.2 x 10(exp -17) A/cm(exp 2) have been measured and the temperature dependence of the reverse saturation current is found to have ideal behavior. A small demonstration system has been assembled that generates and stores enough electricity to light up an LED.

Study on and the implementation of solar powered street lighting in SEEE, USM

NASA Astrophysics Data System (ADS)

Arshad, M. S.; Ain, M. F.; Ishak, D.; Rahman, A. L. A.; Nazri, A. S.; Abdullah, M. N.; Kaharuddin, S.; Hussin, R.

2017-10-01

Solar Powered Street Lights is a project that can be served to School of Electrical & Electronic Engineering (SEEE), Universiti Sains Malaysia in electricity cost savings by implementing the existing solar Photovoltaic (PV) system used for a green technology of energy efficiency. Due to the electricity of the national grid Tenaga Nasional Berhad (TNB) continue to increases, perhaps this system is able to maximize cost savings for SEEE. Solar energy collected during the day will be converted into electricity to charge the battery. Electricity charged the battery then will be connected and used to power the lights around the SEEE parking area at night. After taking all important aspects into accounts that help to optimize energy saving, this system has been proven to reduce electricity costs. System data such as the power consumption of the load, battery charging rates, and other relevant data is measured. From the measured data, calculations and analysis were performed to determine the actual performance of the system. Proper wiring connections between solar PV systems and light poles grid around the SEEE parking lot have been executed. As a result, the implementation of this system could save as much as RM 462.86 for the cost of monthly electricity bills incurred by the SEEE.

Rigorous theory of graded thermoelectric converters including finite heat transfer coefficients

NASA Astrophysics Data System (ADS)

Gerstenmaier, York Christian; Wachutka, Gerhard

2017-11-01

Maximization of thermoelectric (TE) converter performance with an inhomogeneous material and electric current distribution has been investigated in previous literature neglecting thermal contact resistances to the heat reservoirs. The heat transfer coefficients (HTCs), defined as inverse thermal contact resistances per unit area, are thus infinite, whereas in reality, always parasitic thermal resistances, i.e., finite HTCs, are present. Maximization of the generated electric power and of cooling power in the refrigerator mode with respect to Seebeck coefficients and heat conductivity for a given profile of the material's TE figure of merit Z are mathematically ill-posed problems in the presence of infinite HTCs. As will be shown in this work, a fully self consistent solution is possible for finite HTCs, and in many respects, the results are fundamentally different. A previous theory for 3D devices will be extended to include finite HTCs and is applied to 1D devices. For the heat conductivity profile, an infinite number of solutions exist leading to the same device performance. Cooling power maximization for finite HTCs in 1D will lead to a strongly enhanced corresponding efficiency (coefficient of performance), whereas results with infinite HTCs lead to a non-monotonous temperature profile and coefficient of performance tending to zero for the prescribed heat conductivities. For maximized generated electric power, the corresponding generator efficiency is nearly a constant independent from the finite HTC values. The maximized efficiencies in the generator and cooling mode are equal to the efficiencies for the infinite HTC, provided that the corresponding powers approach zero. These and more findings are condensed in 4 theorems in the conclusions.

Multiscaling statistics of high frequency global solar radiation data in the Guadeloupean Archipelago

NASA Astrophysics Data System (ADS)

Calif, R.; Schmitt, F. G.; Huang, Y.; Soubdhan, T.

2013-12-01

The part of the solar power production from photovoltaiccs systems is constantly increasing in the electric grids. Solar energy converter devices such as photovoltaic cells are very sensitive to instantaneous solar radiation fluctuations. Thus rapid variation of solar radiation due to changes in the local meteorological condition can induce large amplitude fluctuations of the produced electrical power and reduce the overall efficiency of the system. When large amount of photovoltaic electricity is send into a weak or small electricity network such as island network, the electric grid security can be in jeopardy due to these power fluctuations. The integration of this energy into the electrical network remains a major challenge, due to the high variability of solar radiation in time and space. To palliate these difficulties, it is essential to identify the characteristic of these fluctuations in order to anticipate the eventuality of power shortage or power surge. A good knowledge of the intermittency of global solar radiation is crucial for selecting the location of a solar power plant and predicting the generation of electricity. This work presents a multifractal analysis study of 367 daily global solar radiation sequences measured with a sampling rate of 1 Hz over one year at Guadeloupean Archipelago (French West Indies) located at 16o15'N latitude and 60o30'W longitude. The mean power spectrum computed follows a power law behaviour close to the Kolmogorov spectrum. The intermittent and multifractal properties of global solar radiation data are investigated using several methods. Under this basis, a characterization for each day using three multifractal parameters is proposed.

A multi-port power electronics interface for battery powered electric vehicles: Application of inductively coupled wireless power transfer and hybrid energy storage system

NASA Astrophysics Data System (ADS)

McDonough, Matthew Kelly

Climate change, pollution, and geopolitical conflicts arising from the extreme wealth concentrations caused by fossil fuel deposits are just a few of the side-effects of the way that we fuel our society. A new method to power our civilization is becoming more and more necessary. Research for new, more sustainable fuel sources is already underway due to research in wind, solar, geothermal, and hydro power. However this focus is mainly on stationary applications. A large portion of fossil fuel usage comes from transportation. Unfortunately, the transition to cleaner transportation fuels is being stunted by the inability to store adequate amounts of energy in electro-chemical batteries. The idea of charging while driving has been proposed by many researchers, however several challenges still exist. In this work some of these challenges are addressed. Specifically, the ability to route power from multiple sources/loads is investigated. Special attention is paid to adjusting the time constant of particular converters, namely the battery and ultra-capacitor converters to reduce the high frequency and high magnitude current components applied to the battery terminals. This is done by developing a closed loop model of the entire multi-port converter, including the state of charge of the ultra-capacitors. The development of closed loop models and two experimental testbeds for use as stationary vehicle charging platforms with their unique set of sources/loads are presented along-side an on-board charger to demonstrate the similarities and differences between stationary charging and mobile charging. Experimental results from each are given showing that it is not only possible, but feasible to utilize Inductively Coupled Wireless Power Transfer (ICWPT) to charge a battery powered electric vehicle while driving and still protect the life-span of the batteries under the new, harsher conditions generated by the ICWPT system.

Advantages and Uses of AMTEC

NASA Astrophysics Data System (ADS)

Lodhi, M. A. K.

2012-10-01

Static conversion systems are gaining importance in recent times because of newer applications of electricity like in spacecraft, hybrid-electric vehicles, military uses and domestic purposes. Of the many new static energy conversion systems that are being considered, one is the Alkali Metal Thermal Electric Converter (AMTEC). It is a thermally regenerative, electrochemical device for the direct conversion of heat to electrical power. As the name suggests, this system uses an alkali metal in its process. The electrochemical process involved in the working of AMTEC is ionization of alkali metal atoms at the interface of electrode and electrolyte. The electrons produced as a result flow through the external load thus doing work, and finally recombine with the metal ions at the cathode. AMTECs convert the work done during the nearly isothermal expansion of metal vapor to produce a high current and low voltage electron flow. Due to its principle of working it has many inherent advantages over other conventional generators. These will be discussed briefly.

Heat Transfer and Geometrical Analysis of Thermoelectric Converters Driven by Concentrated Solar Radiation

PubMed Central

Suter, Clemens; Tomeš, Petr; Weidenkaff, Anke; Steinfeld, Aldo

2010-01-01

A heat transfer model that couples radiation/conduction/convection heat transfer with electrical potential distribution is developed for a thermoelectric converter (TEC) subjected to concentrated solar radiation. The 4-leg TEC module consists of two pairs of p-type La1.98Sr0.02CuO4 and n-type CaMn0.98Nb0.02O3 legs that are sandwiched between two ceramic Al2O3 hot/cold plates and connected electrically in series and thermally in parallel. The governing equations for heat transfer and electrical potential are formulated, discretized and solved numerically by applying the finite volume (FV) method. The model is validated in terms of experimentally measured temperatures and voltages/power using a set of TEC demonstrator modules, subjected to a peak radiative flux intensity of 300 suns. The heat transfer model is then applied to examine the effect of the geometrical parameters (e.g. length/width of legs) on the solar-to-electricity energy conversion efficiency.

Design, Synthesis and Characterization of Novel Nonlinear Optical Polymers

DTIC Science & Technology

1993-05-31

to-Digital Converter Research Grant, February 1, 1992 - January 31, 1993 - $5,000.00 Electric Power Research Institute Evaluation of Unique Solar ...Chittibabu, M. Kamath, J. Kumar and S.K. Tripathy) Materials Research Society, Boston, Massachusetts, December 1992. 7. "Novel Solvato- and Thermochromic

13. Bottom floor, tower interior showing concrete floor and cast ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. Bottom floor, tower interior showing concrete floor and cast iron bases for oil butts (oil butts removed when lighthouse lamp was converted to electric power.) - Block Island Southeast Light, Spring Street & Mohegan Trail at Mohegan Bluffs, New Shoreham, Washington County, RI

Heterogeneous reduction of carbon dioxide by hydride-terminated silicon nanocrystals

PubMed Central

Sun, Wei; Qian, Chenxi; He, Le; Ghuman, Kulbir Kaur; Wong, Annabelle P. Y.; Jia, Jia; Jelle, Abdinoor A.; O'Brien, Paul G.; Reyes, Laura M.; Wood, Thomas E.; Helmy, Amr S.; Mims, Charles A.; Singh, Chandra Veer; Ozin, Geoffrey A.

2016-01-01

Silicon constitutes 28% of the earth's mass. Its high abundance, lack of toxicity and low cost coupled with its electrical and optical properties, make silicon unique among the semiconductors for converting sunlight into electricity. In the quest for semiconductors that can make chemicals and fuels from sunlight and carbon dioxide, unfortunately the best performers are invariably made from rare and expensive elements. Here we report the observation that hydride-terminated silicon nanocrystals with average diameter 3.5 nm, denoted ncSi:H, can function as a single component heterogeneous reducing agent for converting gaseous carbon dioxide selectively to carbon monoxide, at a rate of hundreds of μmol h−1 g−1. The large surface area, broadband visible to near infrared light harvesting and reducing power of SiH surface sites of ncSi:H, together play key roles in this conversion. Making use of the reducing power of nanostructured hydrides towards gaseous carbon dioxide is a conceptually distinct and commercially interesting strategy for making fuels directly from sunlight. PMID:27550234

Advanced Receiver/Converter Experiments for Laser Wireless Power Transmission

NASA Technical Reports Server (NTRS)

Howell, Joe T.; ONeill, Mark; Fork, Richard

2004-01-01

For several years NASA Marshall Space Flight Center, UAH and ENTECH have been working on various aspects of space solar power systems. The current activity was just begun in January 2004 to further develop this new photovoltaic concentrator laser receiver/converter technology. During the next few months, an improved prototype will be designed, fabricated, and thoroughly tested under laser illumination. The final paper will describe the new concept, present its advantages over other laser receiver/converter approaches (including planar photovoltaic arrays), and provide the latest experiment results on prototype hardware (including the effects of laser irradiance level and cell temperature). With NASA's new human exploration plans to first return to the Moon, and then to proceed to Mars, the new photovoltaic concentrator laser receiver/converter technology could prove to be extremely useful in providing power to the landing sites and other phases of the missions. For example, to explore the scientifically interesting and likely resource-rich poles of the Moon (which may contain water) or the poles of Mars (which definitely contain water and carbon dioxide), laser power beaming could represent the simplest means of providing power to these regions, which receive little or no sunlight, making solar arrays useless there. In summary, the authors propose a paper on definition and experimental results of a novel photovoltaic concentrator approach for collecting and converting laser radiation to electrical power. The new advanced photovoltaic concentrator laser receiver/converter offers higher performance, lighter weight, and lower cost than competing concepts, and early experimental results are confirming the expected excellent Performance levels. After the small prototypes are successfully demonstrated, a larger array with even better performance is planned for the next phase experiments and demonstrations. Thereafter, a near-term flight experiment of the new technology should be developed and flown, to lay the groundwork for future space power applications in the Earth-Moon neighborhood, and ultimately encompassing Mars and its environs.

A mechanical energy harvested magnetorheological damper with linear-rotary motion converter

NASA Astrophysics Data System (ADS)

Chu, Ki Sum; Zou, Li; Liao, Wei-Hsin

2016-04-01

Magnetorheological (MR) dampers are promising to substitute traditional oil dampers because of adaptive properties of MR fluids. During vibration, significant energy is wasted due to the energy dissipation in the damper. Meanwhile, for conventional MR damping systems, extra power supply is needed. In this paper, a new energy harvester is designed in an MR damper that integrates controllable damping and energy harvesting functions into one device. The energy harvesting part of this MR damper has a unique mechanism converting linear motion to rotary motion that would be more stable and cost effective when compared to other mechanical transmissions. A Maxon motor is used as a power generator to convert the mechanical energy into electrical energy to supply power for the MR damping system. Compared to conventional approaches, there are several advantages in such an integrated device, including weight reduction, ease in installation with less maintenance. A mechanical energy harvested MR damper with linear-rotary motion converter and motion rectifier is designed, fabricated, and tested. Experimental studies on controllable damping force and harvested energy are performed with different transmissions. This energy harvesting MR damper would be suitable to vehicle suspensions, civil structures, and smart prostheses.

Fossil fuel combined cycle power generation method

DOEpatents

Labinov, Solomon D [Knoxville, TN; Armstrong, Timothy R [Clinton, TN; Judkins, Roddie R [Knoxville, TN

2008-10-21

A method for converting fuel energy to electricity includes the steps of converting a higher molecular weight gas into at least one mixed gas stream of lower average molecular weight including at least a first lower molecular weight gas and a second gas, the first and second gases being different gases, wherein the first lower molecular weight gas comprises H.sub.2 and the second gas comprises CO. The mixed gas is supplied to at least one turbine to produce electricity. The mixed gas stream is divided after the turbine into a first gas stream mainly comprising H.sub.2 and a second gas stream mainly comprising CO. The first and second gas streams are then electrochemically oxidized in separate fuel cells to produce electricity. A nuclear reactor can be used to supply at least a portion of the heat the required for the chemical conversion process.

The Electric Power System of the International Space Station: A Platform for Power Technology Development

NASA Technical Reports Server (NTRS)

Gietl, Eric B.; Gholdston, Edward W.; Manners, Bruce A.; Delventhal, Rex A.

2000-01-01

The electrical power system developed for the International Space Station represents the largest space-based power system ever designed and, consequently, has driven some key technology aspects and operational challenges. The full U.S.-built system consists of a 160-Volt dc primary network, and a more tightly regulated 120-Volt dc secondary network. Additionally, the U.S. system interfaces with the 28-Volt system in the Russian segment. The international nature of the Station has resulted in modular converters, switchgear, outlet panels, and other components being built by different countries, with the associated interface challenges. This paper provides details of the architecture and unique hardware developed for the Space Station, and examines the opportunities it provides for further long-term space power technology development, such as concentrating solar arrays and flywheel energy storage systems.

Consideration of impedance matching techniques for efficient piezoelectric energy harvesting.

PubMed

Kim, Hyeoungwoo; Priya, Shashank; Stephanou, Harry; Uchino, Kenji

2007-09-01

This study investigates multiple levels of impedance-matching methods for piezoelectric energy harvesting in order to enhance the conversion of mechanical to electrical energy. First, the transduction rate was improved by using a high piezoelectric voltage constant (g) ceramic material having a magnitude of g33 = 40 x 10(-3) V m/N. Second, a transducer structure, cymbal, was optimized and fabricated to match the mechanical impedance of vibration source to that of the piezoelectric transducer. The cymbal transducer was found to exhibit approximately 40 times higher effective strain coefficient than the piezoelectric ceramics. Third, the electrical impedance matching for the energy harvesting circuit was considered to allow the transfer of generated power to a storage media. It was found that, by using the 10-layer ceramics instead of the single layer, the output current can be increased by 10 times, and the output load can be reduced by 40 times. Furthermore, by using the multilayer ceramics the output power was found to increase by 100%. A direct current (DC)-DC buck converter was fabricated to transfer the accumulated electrical energy in a capacitor to a lower output load. The converter was optimized such that it required less than 5 mW for operation.

Novel, Integrated Reactor / Power Conversion System (LMR-AMTEC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pablo Rubiolo, Principal Investigator

2003-03-21

The main features of this project were the development of a long life (up to 10 years) Liquid Metal Reactor (LMR) and a static conversion subsystem comprising an Alkali Metal Thermal-to-Electric (AMTEC) topping cycle and a ThermoElectric (TE) Bottom cycle. Various coupling options of the LMR with the energy conversion subsystem were explored and, base in the performances found in this analysis, an Indirect Coupling (IC) between the LMR and the AMTEC/TE converters with Alkali Metal Boilers (AMB) was chosen as the reference design. The performance model of the fully integrated sodium-and potassium-AMTEC/TE converters shows that a combined conversion efficiencymore » in excess of 30% could be achieved by the plant. (B204)« less

A review of the thermoelectronic laser energy converter (TELEC) program at Lewis Research Center

NASA Technical Reports Server (NTRS)

Alger, D. L.; Manista, E. J.; Thompson, R. W.

1978-01-01

The investigation of the Thermoelectronic Laser Energy Converter (TELEC) concept began with a feasibility study of a 1 megawatt sized TELEC system. The TELEC was to use either cesium vapor or hydrogen as the plasma medium. The cesium vapor TELEC appears to be the more practical device studied with an overall calculated conversion efficiency of greater than 48%. Following this study, a small TELEC cell was fabricated which demonstrated the conversion of a small amount of laser power to electrical power. The cell developed a short circuit current of 0.7 amperes and an open circuit voltage, as extrapolated from volt-ampere curves, of about 1.5 volts.

Performance Analysis of Three-Phase Induction Motor with AC Direct and VFD

NASA Astrophysics Data System (ADS)

Kumar, Dinesh

2018-03-01

The electrical machine analysis and performance calculation is a very important aspect of efficient drive system design. The development of power electronics devices and power converters provide smooth speed control of Induction Motors by changing the frequency of input supply. These converters, on one hand are providing a more flexible speed control that also leads to problems of harmonics and their associated ailments like pulsating torque, distorted current and voltage waveforms, increasing losses etc. This paper includes the performance analysis of three phase induction motor with three-phase AC direct and variable frequency drives (VFD). The comparison has been concluded with respect to various parameters. MATLAB-SIMULINKTM is used for the analysis.

Design of PI Controlled Non Isolated Bidirectional DC to DC Converter for Electric Vehicle Application

NASA Astrophysics Data System (ADS)

Geetha, A.; Subramani, C.; Thamizh Thentral, T. M.; Krithika, V.; Usha, S.

2018-04-01

Non isolated Bidirectional DC-DC Converter (NIBDDC) is a good interface between DC source and inverter Fed induction motor drive. This paper deals with comparison between open loop and PI controlled Bidirectional DC to DC Converter Inverter System (BDDCIS). The modelling and control of BDDC is becomes an important issue. Open loop BDDCIS and closed loop PI controlled BDDCIS are designed, modelled and simulated using Matlab- simulink and their results are presented. The investigations indicate superior performance of PI controlled BDDCIS. The proposed BDDCIS has advantages like bidirectional power transfer ability, reduced hardware count and improved dynamic response.

Fully Electrical Modeling of Thermoelectric Generators with Contact Thermal Resistance Under Different Operating Conditions

NASA Astrophysics Data System (ADS)

Siouane, Saima; Jovanović, Slaviša; Poure, Philippe

2017-01-01

The Seebeck effect is used in thermoelectric generators (TEGs) to supply electronic circuits by converting the waste thermal into electrical energy. This generated electrical power is directly proportional to the temperature difference between the TEG module's hot and cold sides. Depending on the applications, TEGs can be used either under constant temperature gradient between heat reservoirs or constant heat flow conditions. Moreover, the generated electrical power of a TEG depends not only on these operating conditions, but also on the contact thermal resistance. The influence of the contact thermal resistance on the generated electrical power have already been extensively reported in the literature. However, as reported in Park et al. (Energy Convers Manag 86:233, 2014) and Montecucco and Knox (IEEE Trans Power Electron 30:828, 2015), while designing TEG-powered circuit and systems, a TEG module is mostly modeled with a Thévenin equivalent circuit whose resistance is constant and voltage proportional to the temperature gradient applied to the TEG's terminals. This widely used simplified electrical TEG model is inaccurate and not suitable under constant heat flow conditions or when the contact thermal resistance is considered. Moreover, it does not provide realistic behaviour corresponding to the physical phenomena taking place in a TEG. Therefore, from the circuit designer's point of view, faithful and fully electrical TEG models under different operating conditions are needed. Such models are mainly necessary to design and evaluate the power conditioning electronic stages and the maximum power point tracking algorithms of a TEG power supply. In this study, these fully electrical models with the contact thermal resistance taken into account are presented and the analytical expressions of the Thévenin equivalent circuit parameters are provided.

A Decision Model for Choosing Among Photovoltaic Technologies to Generate Electricity at Grid-Connected Air Force Facilities: A Value-Focused Approach

DTIC Science & Technology

2006-03-01

goals, but it is also carries significant political interest. 1.1.4. Photovoltaic Effect A monocrystalline silicon photovoltaic cell (Figure 2) is...developed the industry by creating small photovoltaic panels to power watches and calculators (Archer, 2001; Wronski and Carlson, 2001). Amorphous silicon...Clinton, 1999). One particularly promising renewable energy source is solar energy converted to electricity by solar photovoltaic panels . Previous

P6 Truss, Photovoltaic (PV) Solar Array Wing (SAW)

NASA Image and Video Library

2000-12-07

STS097-376-019 (7 December 2000) --- A close-up view of the P6 solar array on the International Space Station (ISS), backdropped against the blackness of space and the Earth’s horizon. The P6 solar array is the first of eight sets of solar arrays that at the completion of the space station construction in 2006, will comprise the station’s electrical power system, converting sunlight to electricity.

P6 Truss, Photovoltaic (PV) Solar Array Wing (SAW)

NASA Image and Video Library

2000-12-07

STS097-376-006 (7 Dec 2000) --- A close-up view of the P6 solar array on the International Space Station (ISS), backdropped against the blackness of space and the Earth?s horizon. The P6 solar array is the first of eight sets of solar arrays that at the completion of the space station construction in 2006, will comprise the station?s electrical power system, converting sunlight to electricity.

Heatpipe space power and propulsion systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Houts, M.G.; Poston, D.I.; Ranken, W.A.

1995-07-01

Safe, reliable, low-mass space power and propulsion systems could have numerous civilian and military applications. This paper discusses two fission-powered concepts: the Heatpipe Power System (HPS) that provides power only, and the Heatpipe Bimodal System (HBS) that provides both power and thermal propulsion. Both concepts have 10 important features. First, only existing technology and recently tested fuel forms are used. Second, fuel can be removed whenever desired, greatly facilitating system fabrication and handling. Third, full electrically heated system testing is possible, with minimal operations required to replace the heaters with fuel and ready the system for launch. Fourth, the systemsmore » are passively subcritical during launch accidents. Fifth, a modular approach is used, and most technical issues can be resolved with inexpensive module tests. Sixth, bonds between dissimilar metals are minimized. Seventh, there are no single point failures during power mode operation. Eighth, fuel burnup rate is quite low to help ensure greater than 10-year system life. Ninth, there are no pumped coolant loops, and the systems can be shut down and restarted without coolant freeze/thaw concerns. Finally, a full ground nuclear test is not needed, and development costs will be low. The baseline HPS uses SNAP-10A-style thermoelectric power converters to produce 5 kWe at a system mass of about 500 kg. The unicouple thermoelectric converters have a hot shoe temperature of 1275 K and reject waste heat at 775 K. This type of thermoelectric converter has been used extensively by the space program, demonstrating an operational lifetime of decades. At higher thermal power, the same core can produce over 10 kWe using thermoelectric converters, and over 50 kWe using advanced power conversion systems.« less

Towards a Microbial Thermoelectric Cell

PubMed Central

Rodríguez-Barreiro, Raúl; Abendroth, Christian; Vilanova, Cristina; Moya, Andrés; Porcar, Manuel

2013-01-01

Microbial growth is an exothermic process. Biotechnological industries produce large amounts of heat, usually considered an undesirable by-product. In this work, we report the construction and characterization of the first microbial thermoelectric cell (MTC), in which the metabolic heat produced by a thermally insulated microbial culture is partially converted into electricity through a thermoelectric device optimized for low ΔT values. A temperature of 41°C and net electric voltage of around 250–600 mV was achieved with 1.7 L baker’s yeast culture. This is the first time microbial metabolic energy has been converted into electricity with an ad hoc thermoelectric device. These results might contribute towards developing a novel strategy to harvest excess heat in the biotechnology industry, in processes such as ethanol fermentation, auto thermal aerobic digestion (ATAD) or bioremediation, which could be coupled with MTCs in a single unit to produce electricity as a valuable by-product of the primary biotechnological product. Additionally, we propose that small portable MTCs could be conceived and inoculated with suitable thermophilic of hyperthermophilic starter cultures and used for powering small electric devices. PMID:23468862

Practical implementation of the concept of converted electric vehicle with advanced traction and dynamic performance and environmental safety indicators

NASA Astrophysics Data System (ADS)

Sidorov, K. M.; Yutt, V. E.; Grishchenko, A. G.; Golubchik, T. V.

2018-02-01

The objective of the work presented in this paper is to describe the implementation of the technical solutions have been developed, with regard to structure, composition, and characteristics, for an experimental prototype of an electric vehicle which has been converted from a conventional vehicle. The methodology of the study results is based on the practical implementation of the developed concept of the conversion of conventional vehicles into electric vehicles. The main components of electric propulsion system of the experimental prototype of electric vehicle are developed and manufactured on the basis of computational researches, taking into account the criteria and principles of conversion within the framework of presented work. The article describes a schematic and a design of power conversion and commutation electrical equipment, traction battery, electromechanical transmission. These results can serve as guidance material in the design and implementation of electric propulsion system (EPS) components of electric vehicles, facilitate the development of optimal technical solutions in the development and manufacture of vehicles, including those aimed at autonomy of operation and the use of perspective driver assistance systems. As part of this work, was suggested a rational structure for an electric vehicle experimental prototype, including technical performance characteristics of the components of EPS.

On-chip enzymatic microbiofuel cell-powered integrated circuits.

PubMed

Mark, Andrew G; Suraniti, Emmanuel; Roche, Jérôme; Richter, Harald; Kuhn, Alexander; Mano, Nicolas; Fischer, Peer

2017-05-16

A variety of diagnostic and therapeutic medical technologies rely on long term implantation of an electronic device to monitor or regulate a patient's condition. One proposed approach to powering these devices is to use a biofuel cell to convert the chemical energy from blood nutrients into electrical current to supply the electronics. We present here an enzymatic microbiofuel cell whose electrodes are directly integrated into a digital electronic circuit. Glucose oxidizing and oxygen reducing enzymes are immobilized on microelectrodes of an application specific integrated circuit (ASIC) using redox hydrogels to produce an enzymatic biofuel cell, capable of harvesting electrical power from just a single droplet of 5 mM glucose solution. Optimisation of the fuel cell voltage and power to match the requirements of the electronics allow self-powered operation of the on-board digital circuitry. This study represents a step towards implantable self-powered electronic devices that gather their energy from physiological fluids.

System design of ELITE power processing unit

NASA Astrophysics Data System (ADS)

Caldwell, David J.

The Electric Propulsion Insertion Transfer Experiment (ELITE) is a space mission planned for the mid 1990s in which technological readiness will be demonstrated for electric orbit transfer vehicles (EOTVs). A system-level design of the power processing unit (PPU), which conditions solar array power for the arcjet thruster, was performed to optimize performance with respect to reliability, power output, efficiency, specific mass, and radiation hardness. The PPU system consists of multiphased parallel switchmode converters, configured as current sources, connected directly from the array to the thruster. The PPU control system includes a solar array peak power tracker (PPT) to maximize the power delivered to the thruster regardless of variations in array characteristics. A stability analysis has been performed to verify that the system is stable despite the nonlinear negative impedance of the PPU input and the arcjet thruster. Performance specifications are given to provide the required spacecraft capability with existing technology.

Energy harvesting with stacked dielectric elastomer transducers: Nonlinear theory, optimization, and linearized scaling law

NASA Astrophysics Data System (ADS)

Tutcuoglu, A.; Majidi, C.

2014-12-01

Using principles of damped harmonic oscillation with continuous media, we examine electrostatic energy harvesting with a "soft-matter" array of dielectric elastomer (DE) transducers. The array is composed of infinitely thin and deformable electrodes separated by layers of insulating elastomer. During vibration, it deforms longitudinally, resulting in a change in the capacitance and electrical enthalpy of the charged electrodes. Depending on the phase of electrostatic loading, the DE array can function as either an actuator that amplifies small vibrations or a generator that converts these external excitations into electrical power. Both cases are addressed with a comprehensive theory that accounts for the influence of viscoelasticity, dielectric breakdown, and electromechanical coupling induced by Maxwell stress. In the case of a linearized Kelvin-Voigt model of the dielectric, we obtain a closed-form estimate for the electrical power output and a scaling law for DE generator design. For the complete nonlinear model, we obtain the optimal electrostatic voltage input for maximum electrical power output.

Baseline tests of the C. H. Waterman DAF electric passenger vehicle

NASA Technical Reports Server (NTRS)

Sargent, N. B.; Maslowski, E. A.; Soltis, R. F.; Schuh, R. M.

1977-01-01

An electric vehicle was tested as part of an Energy Research Development Administration (ERDA) project to characterize the state-of-the-art of electric vehicles. The Waterman vehicle performance test results are presented in this report. The vehicle is a converted four-passenger DAF 46 sedan. It is powered by sixteen 6-volt traction batteries through a three-step contactor controller actuated by a foot throttle to change the voltage applied to the 6.7 kW motor. The braking system is a conventional hydraulic braking system.

Satellite Power System (SPS). State and local regulations as applied to satellite power system microwave receiving antenna facilities

NASA Technical Reports Server (NTRS)

Kotin, A. D.

1978-01-01

State and local regulation of power plant construction and operation of solar power satellite (SPS) receiving stations is presented. Each receiving antenna station occupies a land area 100-200 km square, receives microwave transmissions from the solar power satellite, and converts them into electricity for transmission to the power grid. The long lead time associated with the SPS and the changing status of state and local regulation dictated emphasis on: generic classification of the types of regulation, and identification of regulatory vectors which affect rectenna facilities.

Space/lunar solar power systems research and needs (1999)

NASA Astrophysics Data System (ADS)

Criswell, David R.; Waldron, Robert D.

1999-01-01

Average per capita incomes of people in the Developed and Developing Nations have been diverging since the 1800s. The divergence increased after World War II. Now the per capita cost of commercial energy in the Developing Nations is a large fraction of the per capita income within the Developing Nations. Solar electric power could be provided to Earth from space or lunar installations. This new source power must be low in cost, <=1 ¢/kWe-h, in order to accelerate economic growth in the Developing Nations. Microwave beams appear to be the preferable method of delivering power to Earth. In order to provide low cost solar-electric power the projected cost of the microwave rectifier/antennas, termed rectennas, must be reduced. A reflector-rectenna is proposed to concentrate microwaves before they are converted by compact sets of antenna/rectifiers to electric power. Rectenna costs may be reduced by a factor of 5 and energy costs to the order of 1 ¢/kWe-h or less. The primary disadvantages of the concentrators are an ~10% loss in efficiency and re-emission of non-captured microwave energy.

Design, Analysis and Implementation of an Experimental System to Harvest Energy From Atmospheric Temperature Variations Using Ethyl Chloride Filled Bellows

NASA Astrophysics Data System (ADS)

Ali, Gibran

The increase in global warming and the dwindling supplies of fossil fuels have shifted the focus from traditional to alternate sources of energy. This has resulted in a concerted effort towards finding new energy sources as well as better understanding traditional renewable energy sources such as wind and solar power. In addition to the shift in focus towards alternate energy, the last two decades have offered a dramatic rise in the use of digital technologies such as wireless sensor networks that require small but isolated power supplies. Energy harvesting, a method to gather energy from ambient sources including sunlight, vibrations, heat, etc., has provided some success in powering these systems. One of the unexplored areas of energy harvesting is the use of atmospheric temperature variations to obtain usable energy. This thesis investigates an innovative mechanism to extract energy from atmospheric variations using ethyl chloride filled mechanical bellows. The energy harvesting process was divided into two parts. The first part consisted of extracting energy from the temperature variations and converting it into the potential energy stored in a linear coil spring. This was achieved by designing and fabricating an apparatus that consisted of an ethyl chloride filled bellows working against a mechanical spring in a closed and controlled environment. The bellows expanded/contracted depending upon the ambient temperature and the energy harvested was calculated as a function of the bellows' length. The experiments showed that 6 J of potential energy may be harvested for a 23°C change in temperature. The numerical results closely correlated to the experimental data with an error magnitude of 1%. In regions with high diurnal temperature variation, such an apparatus may yield approximately 250 microwatts depending on the diurnal temperature range. The second part of the energy harvesting process consisted of transforming linear expansion of the bellows into electric power. A system was designed and simulated using Mathworks Simulink and SimDriveline packages that converted the linear oscillations of the bellows into electric power. This was achieved in two steps; a gear train was designed that would convert the linear displacement of the bellows into potential energy stored in a spiral spring. The spiral spring would then periodically engage to a small generator producing electric power. The electrical power generated was found to depend solely on the potential energy stored in the spring. It was discovered that for a sinusoidal force with constant amplitude and frequency, the potential energy stored in the spring depended on the duration of force input and the parameters of the drivetrain such as the spring stiffness, the gear ratios, and the pinion radii. After simulating the system for different parameters, an optimal set of values was presented to maximize the electrical energy output for a given duration of time. For constant amplitude (120 N) sinusoidal force input with a time period of T seconds, the system stored 37 J, 65 J, and 90 J after a time of 3T, 5T, and 7T, respectively. The electric power output was 7.14 microwatts for a conversion efficiency of 5%. The next step is building a physical geartrain generator assembly based on the design presented in the thesis. The physical system will first be verified by simulating the force input using a pneumatic cylinder. The two parts of the research experiment can then be integrated into one system that would generate electric power directly from temporal temperature and pressure variations.

Hydrogen storage in the form of metal hydrides

NASA Technical Reports Server (NTRS)

Zwanziger, M. G.; Santana, C. C.; Santos, S. C.

1984-01-01

Reversible reactions between hydrogen and such materials as iron/titanium and magnesium/ nickel alloy may provide a means for storing hydrogen fuel. A demonstration model of an iron/titanium hydride storage bed is described. Hydrogen from the hydride storage bed powers a converted gasoline electric generator.

Hybrid: Braking

Science.gov Websites

Button Stopped button highlighted subbanner graphic: gray bar STOPPED When the vehicle is stopped engine when additional power is needed. It also acts as a generator, converting energy from the engine or engine instantly when needed. Main stage: See through car with battery, engine, and electric motor

Propulsion System Technology for Military Land Vehicles

DTIC Science & Technology

1981-08-01

torques) to decrease specific weight and volume; and (3) hybrid transmissions using low-torque devices (electrical converters or traction drives) with a... VEICLE SPEC POMWE, bWtu FIGURE 1. Impact of vehicle specific power on weight and manufacturing cost of armored vehicles. 15 [ 𔃺!00, LCV .30 *1

International energy annual 1997

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

The International Energy Annual presents an overview of key international energy trends for production, consumption, imports, and exports of primary energy commodities in over 220 countries, dependencies, and areas of special sovereignty. Also included are population and gross domestic product data, as well as prices for crude oil and petroleum products in selected countries. Renewable energy reported in the International Energy Annual includes hydroelectric power and geothermal, solar, and wind electric power. Also included are biomass electric power for Brazil and the US, and biomass, geothermal, and solar energy produced in the US and not used for electricity generation. Thismore » report is published to keep the public and other interested parties fully informed of primary energy supplies on a global basis. The data presented have been largely derived from published sources. The data have been converted to units of measurement and thermal values (Appendices E and F) familiar to the American public. 93 tabs.« less

Electrical cable utilization for wave energy converters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bull, Diana; Baca, Michael; Schenkman, Benjamin

Here, this paper investigates the suitability of sizing the electrical export cable based on the rating of the contributing WECs within a farm. These investigations have produced a new methodology to evaluate the probabilities associated with peak power values on an annual basis. It has been shown that the peaks in pneumatic power production will follow an exponential probability function for a linear model. A methodology to combine all the individual probability functions into an annual view has been demonstrated on pneumatic power production by a Backward Bent Duct Buoy (BBDB). These investigations have also resulted in a highly simplifiedmore » and perfunctory model of installed cable cost as a function of voltage and conductor cross-section. This work solidifies the need to determine electrical export cable rating based on expected energy delivery as opposed to device rating as small decreases in energy delivery can result in cost savings.« less

Electrical cable utilization for wave energy converters

DOE PAGES

Bull, Diana; Baca, Michael; Schenkman, Benjamin

2018-04-27

Here, this paper investigates the suitability of sizing the electrical export cable based on the rating of the contributing WECs within a farm. These investigations have produced a new methodology to evaluate the probabilities associated with peak power values on an annual basis. It has been shown that the peaks in pneumatic power production will follow an exponential probability function for a linear model. A methodology to combine all the individual probability functions into an annual view has been demonstrated on pneumatic power production by a Backward Bent Duct Buoy (BBDB). These investigations have also resulted in a highly simplifiedmore » and perfunctory model of installed cable cost as a function of voltage and conductor cross-section. This work solidifies the need to determine electrical export cable rating based on expected energy delivery as opposed to device rating as small decreases in energy delivery can result in cost savings.« less

Thermo-Magneto-Electric Generator Arrays for Active Heat Recovery System

PubMed Central

Chun, Jinsung; Song, Hyun-Cheol; Kang, Min-Gyu; Kang, Han Byul; Kishore, Ravi Anant; Priya, Shashank

2017-01-01

Continued emphasis on development of thermal cooling systems is being placed that can cycle low grade heat. Examples include solar powered unmanned aerial vehicles (UAVs) and data storage servers. The power efficiency of solar module degrades at elevated temperature, thereby, necessitating the need for heat extraction system. Similarly, data centres in wireless computing system are facing increasing efficiency challenges due to high power consumption associated with managing the waste heat. We provide breakthrough in addressing these problems by developing thermo-magneto-electric generator (TMEG) arrays, composed of soft magnet and piezoelectric polyvinylidene difluoride (PVDF) cantilever. TMEG can serve dual role of extracting the waste heat and converting it into useable electricity. Near room temperature second-order magnetic phase transition in soft magnetic material, gadolinium, was employed to obtain mechanical vibrations on the PVDF cantilever under small thermal gradient. TMEGs were shown to achieve high vibration frequency at small temperature gradients, thereby, demonstrating effective heat transfer. PMID:28145516

Thermo-Magneto-Electric Generator Arrays for Active Heat Recovery System.

PubMed

Chun, Jinsung; Song, Hyun-Cheol; Kang, Min-Gyu; Kang, Han Byul; Kishore, Ravi Anant; Priya, Shashank

2017-02-01

Continued emphasis on development of thermal cooling systems is being placed that can cycle low grade heat. Examples include solar powered unmanned aerial vehicles (UAVs) and data storage servers. The power efficiency of solar module degrades at elevated temperature, thereby, necessitating the need for heat extraction system. Similarly, data centres in wireless computing system are facing increasing efficiency challenges due to high power consumption associated with managing the waste heat. We provide breakthrough in addressing these problems by developing thermo-magneto-electric generator (TMEG) arrays, composed of soft magnet and piezoelectric polyvinylidene difluoride (PVDF) cantilever. TMEG can serve dual role of extracting the waste heat and converting it into useable electricity. Near room temperature second-order magnetic phase transition in soft magnetic material, gadolinium, was employed to obtain mechanical vibrations on the PVDF cantilever under small thermal gradient. TMEGs were shown to achieve high vibration frequency at small temperature gradients, thereby, demonstrating effective heat transfer.

High-frequency matrix converter with square wave input

DOEpatents

Carr, Joseph Alexander; Balda, Juan Carlos

2015-03-31

A device for producing an alternating current output voltage from a high-frequency, square-wave input voltage comprising, high-frequency, square-wave input a matrix converter and a control system. The matrix converter comprises a plurality of electrical switches. The high-frequency input and the matrix converter are electrically connected to each other. The control system is connected to each switch of the matrix converter. The control system is electrically connected to the input of the matrix converter. The control system is configured to operate each electrical switch of the matrix converter converting a high-frequency, square-wave input voltage across the first input port of the matrix converter and the second input port of the matrix converter to an alternating current output voltage at the output of the matrix converter.

Status of thermoelectronic laser energy conversion, TELEC

NASA Technical Reports Server (NTRS)

Britt, E. J.

1982-01-01

A concept known as a thermo-electronic laser energy converter (TELEC), was studied as a method of converting a 10.6 micron CO2 laser beam into electric power. The calculated characteristics of a TELEC seem to be well matched to the requirements of a spacecraft laser energy conversion system. The TELEC is a high power density plasma device which absorbs an intense laser beam by inverse bremsstrahlung with the plasma electrons. In the TELEC process, electromagnetic radiation is absorbed directly in the plasma electrons producing a high electron temperature. The energetic electrons diffuse out of the plasma striking two electrodes which are in contact with the plasma at the boundaries. These two electrodes have different areas: the larger one is designated as the collector, the smaller one is designated as the emitter. The smaller electrode functions as an electron emitter provide continuity of the current. Waste heat is rejected from the collector electrode. An experiment was carried out with a high power laser using a cesium vapor TELEC cell with 30 cm active length. Laser supported plasma were produced in the TELEC device during a number of laser runs over a period of several days. Electric power from the TELEC was observed with currents in the range of several amperes and output potentials of less than 1 volt.

Thermionic Power Cell To Harness Heat Energies for Geothermal Applications

NASA Technical Reports Server (NTRS)

Manohara, Harish; Mojarradi, Mohammad; Greer, Harold F.

2011-01-01

A unit thermionic power cell (TPC) concept has been developed that converts natural heat found in high-temperature environments (460 to 700 C) into electrical power for in situ instruments and electronics. Thermionic emission of electrons occurs when an emitter filament is heated to gwhite hot h temperatures (>1,000 C) allowing electrons to overcome the potential barrier and emit into the vacuum. These electrons are then collected by an anode, and transported to the external circuit for energy storage.

Advances in thin-film solar cells for lightweight space photovoltaic power

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Bailey, Sheila G.; Flood, Dennis J.

1989-01-01

The development of photovoltaic arrays beyond the next generation is discussed with attention given to the potentials of thin-film polycrystalline and amorphous cells. Of particular importance is the efficiency (the fraction of incident solar energy converted to electricity) and specific power (power to weight ratio). It is found that the radiation tolerance of thin-film materials is far greater than that of single crystal materials. CuInSe2 shows no degradation when exposed to 1-MeV electrons.

Estimation of power in low velocity vertical axis wind turbine

NASA Astrophysics Data System (ADS)

Sampath, S. S.; Shetty, Sawan; Chithirai Pon Selvan, M.

2015-06-01

The present work involves in the construction of a vertical axis wind turbine and the determination of power. Various different types of turbine blades are considered and the optimum blade is selected. Mechanical components of the entire setup are built to obtain maximum rotation per minute. The mechanical energy is converted into the electrical energy by coupling coaxially between the shaft and the generator. This setup produces sufficient power for consumption of household purposes which is economic and easily available.

Design Considerations for Clean QED Fusion Propulsion Systems

NASA Astrophysics Data System (ADS)

Bussard, Robert W.; Jameson, Lorin W.

1994-07-01

The direct production of electric power appears possible from fusion reactions between fuels whose products consist solely of charged particles and thus do not present radiation hazards from energetic neutron production, as do reactions involving deuteron-bearing fuels. Among these are the fuels p, 11B, 3He, and 6Li. All of these can be ``burned'' in inertial-electrostatic-fusion (IEF) devices to power QED fusion-electric rocket engines. These IEF sources provide direct-converted electrical power at high voltage (MeV) to drive e-beams for efficient propellant heating to extreme temperatures, with resulting high specific impulse performance capabilities. IEF/QED engine systems using p11B can outperform all other advanced concepts for controlled fusion propulsion by 2-3 orders of magnitude, while 6Li6Li fusion yields one order of magnitude less advance. Either of these fusion rocket propulsion systems can provide very rapid transit for solar system missions, with high payload fractions in single-stage vehicles. The 3He3He reaction can not be used practically for direct electric conversion because of the wide spread in energy of its fusion products. However, it may eventually prove useful for thermal/electrical power generation in central station power plants, or for direct-fusion-product (DFP) propellant heatingin advanced deep-space rocket engines.

Wind farm electrical system

DOEpatents

Erdman, William L.; Lettenmaier, Terry M.

2006-07-04

An approach to wind farm design using variable speed wind turbines with low pulse number electrical output. The output of multiple wind turbines are aggregated to create a high pulse number electrical output at a point of common coupling with a utility grid network. Power quality at each individual wind turbine falls short of utility standards, but the aggregated output at the point of common coupling is within acceptable tolerances for utility power quality. The approach for aggregating low pulse number electrical output from multiple wind turbines relies upon a pad mounted transformer at each wind turbine that performs phase multiplication on the output of each wind turbine. Phase multiplication converts a modified square wave from the wind turbine into a 6 pulse output. Phase shifting of the 6 pulse output from each wind turbine allows the aggregated output of multiple wind turbines to be a 24 pulse approximation of a sine wave. Additional filtering and VAR control is embedded within the wind farm to take advantage of the wind farm's electrical impedence characteristics to further enhance power quality at the point of common coupling.

A Study on Electric Power Smoothing System for Lead-Acid Battery of Stand-Alone Natural Energy Power System Using EDLC

NASA Astrophysics Data System (ADS)

Jia, Yan; Shibata, Ryosuke; Yamamura, Naoki; Ishida, Muneaki

To resolve energy shortage and global warming problem, renewable natural resource and its power system has been gradually generalizing. However, the power fluctuation suppressing in short period and the balance control of consumption and supply in long period are two of main problems that need to be resolved urgently in natural energy power system. In Stand-alone Natural Energy Power System (SNEPS) with power energy storage devices, power fluctuation in short period is one of the main reasons that recharge cycle times increase and lead-acid battery early failure. Hence, to prolong the service life of lead-acid battery and improve power quality through suppressing the power fluctuation, we proposed a method of electric power smoothing for lead-acid battery of SNEPS using bi-directional Buck/Boost converter and Electric Double Layer Capacitor (EDLC) in this paper. According to the test data of existing SNEPS, a power fluctuation condition is selected and as an example to analyze the validity of the proposed method. The analysis of frequency characteristics indicates the power fluctuation is suppressed a desired range in the target frequency region. The experimental results of confirmed the feasibility of the proposed system and the results well satisfy the requirement of system design.

Designing and Testing Energy Harvesters Suitable for Renewable Power Sources

NASA Astrophysics Data System (ADS)

Synkiewicz, B.; Guzdek, P.; Piekarski, J.; Zaraska, K.

2016-01-01

Energy harvesters convert waste power (heat, light and vibration) directly to electric power . Fast progress in their technology, design and areas of application (e.g. “Internet of Things”) has been observed recently. Their effectiveness is steadily growing which makes their application to powering sensor networks with wireless data transfer reasonable. The main advantage is the independence from wired power sources, which is especially important for monitoring state of environmental parameters. In this paper we describe the design and realization of a gas sensor monitoring CO level (powered by TEG) and two, designed an constructed in ITE, autonomous power supply modules powered by modern photovoltaic cells.

Motor Drive Technologies for the Power-by-Wire (PBW) Program: Options, Trends and Tradeoffs

NASA Technical Reports Server (NTRS)

Elbuluk, Malik E.; Kankam, M. David

1995-01-01

Power-By-Wire (PBW) is a program involving the replacement of hydraulic and pneumatic systems currently used in aircraft with an all-electric secondary power system. One of the largest loads of the all-electric secondary power system will be the motor loads which include pumps, compressors and Electrical Actuators (EA's). Issues of improved reliability, reduced maintenance and efficiency, among other advantages, are the motivation for replacing the existing aircraft actuators with electrical actuators. An EA system contains four major components. These are the motor, the power electronic converters, the actuator and the control system, including the sensors. This paper is a comparative literature review in motor drive technologies, with a focus on the trends and tradeoffs involved in the selection of a particular motor drive technology. The reported research comprises three motor drive technologies. These are the induction motor (IM), the brushless dc motor (BLDCM) and the switched reluctance motor (SRM). Each of the three drives has the potential for application in the PBW program. Many issues remain to be investigated and compared between the three motor drives, using actual mechanical loads expected in the PBW program.

Preliminary review of biomass energy options in Costa Rica and the national alcohol fuel program. Summary report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, J.L.

1981-01-30

For an agricultural, oil-importing country such as Costa Rica, the use of biomass as a source of transportation fuels is a topic of great interest. This analysis is intended to assist the Costa Rican government and USAID/CR to identify possible biomass energy projects. While emphasis is on technologies for converting biomass into liquid fuels, agronomic issues and alternative energy options are also explored. Costa Rica plans to build six facilities for converting biomass (primarily sugarcane, supplemented by molasses, cassava, and banana wastes) to hydrous ethanol. The following issues relating to biomass conversion technologies are identified: use of hydroelectrically powered drivesmore » in sugarcane processing to allow use of bagasse as a fuel; possible sources and costs of energy for converting starch crops like cassava to ethanol; the optimal method for treating stillage; and the feasibility of using fermentation reactors. No definitive recommendation on the scale of ethanol production is made due to the lack of an environmental impact assessment. Finally, with regard to nonalcohol renewable energy, several ideas warrant consideration: electrically powered mass transit; electric cars; vehicle-mounted gasifiers operating on wood chips or pelletized fuels produced from excess bagasse; anaerobic digestion of animal manure and other agricultural wastes; and energy recovery from municipal solid wastes.« less

Reduced energy consumption by massive thermoelectric waste heat recovery in light duty trucks

NASA Astrophysics Data System (ADS)

Magnetto, D.; Vidiella, G.

2012-06-01

The main objective of the EC funded HEATRECAR project is to reduce the energy consumption and curb CO2 emissions of vehicles by massively harvesting electrical energy from the exhaust system and re-use this energy to supply electrical components within the vehicle or to feed the power train of hybrid electrical vehicles. HEATRECAR is targeting light duty trucks and focuses on the development and the optimization of a Thermo Electric Generator (TEG) including heat exchanger, thermoelectric modules and DC/DC converter. The main objective of the project is to design, optimize and produce a prototype system to be tested on a 2.3l diesel truck. The base case is a Thermo Electric Generator (TEG) producing 1 KWel at 130 km/h. We present the system design and estimated output power from benchmark Bi2Te3 modules. We discuss key drivers for the optimization of the thermal-to-electric efficiency, such as materials, thermo-mechanical aspects and integration.

The water intensity of the plugged-in automotive economy.

PubMed

King, Carey W; Webber, Michael E

2008-06-15

Converting light-duty vehicles from full gasoline power to electric power, by using either hybrid electric vehicles or fully electric power vehicles, is likely to increase demand for water resources. In the United States in 2005, drivers of 234 million cars, lighttrucks, and SUVs drove approximately 2.7 trillion miles and consumed over 380 million gallons of gasoline per day. We compare figures from literature and government surveys to calculate the water usage, consumption, and withdrawal, in the United States during petroleum refining and electricity generation. In displacing gasoline miles with electric miles, approximately 2-3 [corrected] times more water is consumed (0.24 [corrected] versus 0.07--0.14 gallons/mile) and over 12 [corrected] times more water is withdrawn (7.8 [corrected] versus 0.6 gallons/mile) primarily due to increased water cooling of thermoelectric power plants to accommodate increased electricity generation. Overall, we conclude that the impact on water resources from a widespread shift to grid-based transportation would be substantial enough to warrant consideration for relevant public policy decision-making. That is not to say that the negative impacts on water resources make such a shift undesirable, but rather this increase in water usage presents a significant potential impact on regional water resources and should be considered when planning for a plugged-in automotive economy.

Extremely-efficient, miniaturized, long-lived alpha-voltaic power source using liquid gallium

NASA Technical Reports Server (NTRS)

Snyder, G. Jeffrey (Inventor); Patel, Jagdishbhai (Inventor); Fleurial, Jean-Pierre (Inventor)

2004-01-01

A power source converts .alpha.-particle energy to electricity for use in electrical systems. Liquid gallium or other liquid medium is subjected to .alpha.-particle emissions. Electrons are freed by collision from neutral gallium atoms to provide gallium ions. The electrons migrate to a cathode while the gallium ions migrate to an anode. A current and/or voltage difference then arises between the cathode and anode because of the work function difference of the cathode and anode. Gallium atoms are regenerated by the receiving of electrons from the anode enabling the generation of additional electrons from additional .alpha.-particle collisions.

Free-piston engine linear generator for hybrid vehicles modeling study

NASA Astrophysics Data System (ADS)

Callahan, T. J.; Ingram, S. K.

1995-05-01

Development of a free piston engine linear generator was investigated for use as an auxiliary power unit for a hybrid electric vehicle. The main focus of the program was to develop an efficient linear generator concept to convert the piston motion directly into electrical power. Computer modeling techniques were used to evaluate five different designs for linear generators. These designs included permanent magnet generators, reluctance generators, linear DC generators, and two and three-coil induction generators. The efficiency of the linear generator was highly dependent on the design concept. The two-coil induction generator was determined to be the best design, with an efficiency of approximately 90 percent.

Verification tests of the U. S. Electricar Corporation Lectric Leopard. Technical report 3 Aug-25 Sep 81

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dowgiallo, E.J. Jr; Snellings, I.R.; Chapman, R.D.

1982-04-01

The Lectric Leopard manufactured by U.S. Electricar Corporation was tested at MERADCOM as part of the Department of Energy project to verify conformity to performance standards of electric vehicles. The Leopard is a standard Fiat Strada sedan which has been converted to an electric vehicle. It is powered by 16 6-V batteries through a silicon-controlled rectifier (SCR) Controller to a 23-hp series-wound d.c. motor. It is equipped with a five-speed manual transmission, power-assisted disc brakes in the front and drum brakes in the rear. It is not equipped with regenerative braking.

Optimal design of a vibration-based energy harvester using magnetostrictive material (MsM)

NASA Astrophysics Data System (ADS)

Hu, J.; Xu, F.; Huang, A. Q.; Yuan, F. G.

2011-01-01

In this study, an optimal vibration-based energy harvesting system using magnetostrictive material (MsM) was designed and tested to enable the powering of a wireless sensor. In particular, the conversion efficiency, converting from magnetic to electric energy, is approximately modeled from the magnetic field induced by the beam vibration. A number of factors that affect the output power such as the number of MsM layers, coil design and load matching are analyzed and explored in the design optimization. From the measurements, the open-circuit voltage can reach 1.5 V when the MsM cantilever beam operates at the second natural frequency 324 Hz. The AC output power is 970 µW, giving a power density of 279 µW cm - 3. The attempt to use electrical reactive components (either inductors or capacitors) to resonate the system at any frequency has also been analyzed and tested experimentally. The results showed that this approach is not feasible to optimize the power. Since the MsM device has low output voltage characteristics, a full-wave quadrupler has been designed to boost the rectified output voltage. To deliver the maximum output power to the load, a complex conjugate impedance matching between the load and the MsM device is implemented using a discontinuous conduction mode (DCM) buck-boost converter. The DC output power after the voltage quadrupler reaches 705 µW and the corresponding power density is 202 µW cm - 3. The output power delivered to a lithium rechargeable battery is around 630 µW, independent of the load resistance.

Effect of Dimension and Shape of Magnet on the Performance AC Generator with Translation Motion

NASA Astrophysics Data System (ADS)

Indriani, A.; Dimas, S.; Hendra

2018-02-01

The development of power plants using the renewable energy sources is very rapid. Renewable energy sources used solar energy, wind energy, ocean wave energy and other energy. All of these renewable energy sources require a processing device or a change of motion system to become electrical energy. One processing device is a generator which have work principle of converting motion (mechanical) energy into electrical energy with rotary shaft, blade and other motion components. Generator consists of several types of rotation motion and linear motion (translational). The generator have components such as rotor, stator and anchor. In the rotor and stator having magnet and winding coil as an electric generating part of the electric motion force. Working principle of AC generator with linear motion (translation) also apply the principle of Faraday that is using magnetic induction which change iron magnet to produce magnetic flux. Magnetic flux is captured by the stator to be converted into electrical energy. Linear motion generators consist of linear induction machine, wound synchronous machine field, and permanent magnet synchronous [1]. Performance of synchronous generator of translation motion is influenced by magnet type, magnetic shape, coil winding, magnetic and coil spacing and others. In this paper focus on the neodymium magnet with varying shapes, number of coil windings and gap of magnetic distances. This generator work by using pneumatic mechanism (PLTGL) for power plants system. Result testing of performance AC generator translation motion obtained that maximum voltage, current and power are 63 Volt for diameter winding coil 0.15 mm, number of winding coil 13000 and distance of magnet 20 mm. For effect shape of magnet, maximum voltage happen on rectangle magnet 30x20x5 mm with 4.64 Volt. Voltage and power on effect of diameter winding coil is 14.63 V and 17.82 W at the diameter winding coil 0.7 and number of winding coil is 1260 with the distance of magnet 25 mm.

Device and method for measuring the coefficient of performance of a heat pump

DOEpatents

Brantley, V.R.; Miller, D.R.

1982-05-18

A method and instrument is provided which allows quick and accurate measurement of the coefficient of performance of an installed electrically powered heat pump including auxiliary resistane heaters. Temperature-sensitive resistors are placed in the return and supply air ducts to measure the temperature increase of the air across the refrigerant and resistive-heating elements of the system. The voltages across the resistors which are directly proportional to the respective duct tempertures are applied to the inputs of a differential amplifier so that its output voltage is proportional to the temperature difference across the unit. A voltage-to-frequency converter connected to the output of the differential amplifier converts the voltage signal to a proportional-frequency signal. A digital watt meter is used to measure the power to the unit and produces a signal having a frequency proportional to the input power. A digital logic circuit ratios the temperature difference signal and the electric power input signal in a unique manner to produce a single number which is the coefficient of performance of the unit over the test interval. The digital logic and an in-situ calibration procedure enables the instrument to make these measurements in such a way that the ratio of heat flow/power input is obtained without computations. No specialized knowledge of thermodynamics or electrons is required to operate the instrument.

Device and method for measuring the coefficient of performance of a heat pump

DOEpatents

Brantley, Vanston R.; Miller, Donald R.

1984-01-01

A method and instrument is provided which allows quick and accurate measurement of the coefficient of performance of an installed electrically powered heat pump including auxiliary resistance heaters. Temperature sensitive resistors are placed in the return and supply air ducts to measure the temperature increase of the air across the refrigerant and resistive heating elements of the system. The voltages across the resistors which are directly proportional to the respective duct temperatures are applied to the inputs of a differential amplifier so that its output voltage is proportional to the temperature difference across the unit. A voltage-to-frequency converter connected to the output of the differential amplifier converts the voltage signal to a proportional frequency signal. A digital watt meter is used to measure the power to the unit and produces a signal having a frequency proportional to the input power. A digital logic circuit ratios the temperature difference signal and the electric power input signal in a unique manner to produce a single number which is the coefficient of performance of the unit over the test interval. The digital logic and an in-situ calibration procedure enables the instrument to make these measurements in such a way that the ratio of heat flow/power input is obtained without computations. No specialized knowledge of thermodynamics or electronics is required to operate the instrument.

Evaluation of electricity production from alkaline pretreated sludge using two-chamber microbial fuel cell.

PubMed

Xiao, Benyi; Yang, Fang; Liu, Junxin

2013-06-15

Electricity production from alkaline pretreated sludge was evaluated using a two-chamber microbial fuel cell (MFC). The electricity production was found to be stable over a long period of time (approximately 17 d) with voltage outputs and power densities of 0.47-0.52 V and 46.80-55.88 mW/m(2), respectively. The anode resistance was the main internal resistance (73.2%) of MFC in the stable stage. Most soluble organic matters (proteins and carbohydrates) in the anode chamber were first degraded and converted into volatile fatty acids (0-15 d), which were then degraded and converted into electricity and methane (15-29 d). The insoluble organics were solubilized thereby decreasing the sludge concentration and reducing the sludge mass. Methane was produced in the anode chamber owing to the growth of methanogens, which did not obviously affect the electricity production. The change in humic-like substances displayed a positive correlation with the electricity production of the MFC. Microbial analysis showed that methanogens and electricity-producing bacteria co-existed mostly on the surface as well as inside the anode. Decreasing the anode resistance and increasing the anode utilization could enhance the electricity production. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

Laser-powered MHD generators for space application

NASA Technical Reports Server (NTRS)

Jalufka, N. W.

1986-01-01

Magnetohydrodynamic (MHD) energy conversion systems of the pulsed laser-supported detonation (LSD) wave, plasma MHD, and liquid-metal MHD (LMMHD) types are assessed for their potential as space-based laser-to-electrical power converters. These systems offer several advantages as energy converters relative to the present chemical, nuclear, and solar devices, including high conversion efficiency, simple design, high-temperature operation, high power density, and high reliability. Of these systems, the Brayton cycle liquid-metal MHD system appears to be the most attractive. The LMMHD technology base is well established for terrestrial applications, particularly with regard to the generator, mixer, and other system components. However, further research is required to extend this technology base to space applications and to establish the technology required to couple the laser energy into the system most efficiently. Continued research on each of the three system types is recommended.

Conceptual design of a 500 watt solar AMTEC space power system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ivanenok, J.F. III; Sievers, R.K.; Harty, R.B.

1995-12-31

Numerous design studies have been completed on Radioisotope powered Alkali Metal Thermal to Electric Converter (RAMTEC) power systems demonstrating their substantial increase in performance. Prior to recent advances in AMTEC technology and Thermal Energy Storage (TES), coupling AMTEC converters with a solar concentrator did not increase the performance of solar powered space power systems. This paper describes a conceptual design of an innovative, low cost, reliable, low mass, long life 500 watt Solar AMTEC (SAMTEC) power system, and the predicted system performance. The concept uses innovative, high voltage AMTEC cells, each containing 7 to 9 small electrolyte tubes, integrated withmore » an individual TES unit. These multi-tube AMTEC cells are identical to the AMTEC cells designed for radioisotope powered systems. The TES used in this conceptual design is the LiF-22%CaF{sub 2} unit currently being developed at NASA Lewis Research Center (LeRC) for the Solar Dynamic Ground Test Demonstration (SDGTD) Program. The system was designed to provide 500 watts of electrical power at 28 volts to a payload in Low Earth Orbit (LEO, 800 km, 28.5{degree} inclination) for a minimum lifetime of 5 years. The SAMTEC power system is predicted to have a specific power k of 5.3 to 8.9 W(e)/kg (including the concentrator, receiver, AMTEC cells, gimbals and drives, structure, power processing and control, and a 30% mass contingency) at the 500 watt power level, and 12 to 17 W(e)/kg at the 5,000 watt power level. The SAMTEC system, including all of the components listed above, is anticipated to cost $1,000/W(e) once development is complete and production begins. The SAMTEC system provides 92% of its Beginning of Life (BOL) power after a 5 year period in LEO, and SAMTEC systems should provide 10 to 15 years of life in LEO. Current AMTEC cells have demonstrated 18% efficiency in the laboratory and have been heated radiatively, with propane flames and electrical resistance heaters.« less