The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Hans Bernhoff - One of the best experts on this subject based on the ideXlab platform.
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Flywheel energy storage for automotive applications
Energies, 2015Co-Authors: Magnus Hedlund, Johan Abrahamsson, Juan De Santiago, Johan Lundin, Hans BernhoffAbstract:A review of flywheel energy storage technology was made, with a special focus on the progress in automotive applications. We found that there are at least 26 university research groups and 27 companies contributing to flywheel technology development. Flywheels are seen to excel in high-power applications, placing them closer in functionality to supercapacitors than to batteries. Examples of Flywheels optimized for vehicular applications were found with a specific power of 5.5 kW/kg and a specific energy of 3.5 Wh/kg. Another flywheel system had 3.15 kW/kg and 6.4 Wh/kg, which can be compared to a state-of-the-art supercapacitor vehicular system with 1.7 kW/kg and 2.3 Wh/kg, respectively. Flywheel energy storage is reaching maturity, with 500 flywheel power buffer systems being deployed for London buses (resulting in fuel savings of over 20%), 400 Flywheels in operation for grid frequency regulation and many hundreds more installed for uninterruptible power supply (UPS) applications. The industry estimates the mass-production cost of a specific consumer-car flywheel system to be 2000 USD. For regular cars, this system has been shown to save 35% fuel in the U.S. Federal Test Procedure (FTP) drive cycle.
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flywheel energy and power storage systems
Renewable & Sustainable Energy Reviews, 2007Co-Authors: Björn Bolund, Hans Bernhoff, Mats LeijonAbstract:For ages Flywheels have been used to achieve smooth operation of machines. The early models where purely mechanical consisting of only a stone wheel attached to an axle. Nowadays Flywheels are complex constructions where energy is stored mechanically and transferred to and from the flywheel by an integrated motor/generator. The stone wheel has been replaced by a steel or composite rotor and magnetic bearings have been introduced. Today Flywheels are used as supplementary UPS storage at several industries world over. Future applications span a wide range including electric vehicles, intermediate storage for renewable energy generation and direct grid applications from power quality issues to offering an alternative to strengthening transmission. One of the key issues for viable flywheel construction is a high overall efficiency, hence a reduction of the total losses. By increasing the voltage, current losses are decreased and otherwise necessary transformer steps become redundant. So far Flywheels over 10Â kV have not been constructed, mainly due to isolation problems associated with high voltage, but also because of limitations in the power electronics. Recent progress in semi-conductor technology enables faster switching and lower costs. The predominant part of prior studies have been directed towards optimising mechanical issues whereas the electro technical part now seem to show great potential for improvement. An overview of flywheel technology and previous projects are presented and moreover a 200Â kW flywheel using high voltage technology is simulated.
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Flywheel energy and power storage systems
Renewable and Sustainable Energy Reviews, 2007Co-Authors: Björn Bolund, Hans Bernhoff, Mats LeijonAbstract:For ages Flywheels have been used to achieve smooth operation of machines. The early models where purely mechanical consisting of only a stone wheel attached to an axle. Nowadays Flywheels are complex constructions where energy is stored mechanically and transferred to and from the flywheel by an integrated motor/generator. The stone wheel has been replaced by a steel or composite rotor and magnetic bearings have been introduced. Today Flywheels are used as supplementary UPS storage at several industries world over. Future applications span a wide range including electric vehicles, intermediate storage for renewable energy generation and direct grid applications from power quality issues to offering an alternative to strengthening transmission. One of the key issues for viable flywheel construction is a high overall efficiency, hence a reduction of the total losses. By increasing the voltage, current losses are decreased and otherwise necessary transformer steps become redundant. So far Flywheels over 10 kV have not been constructed, mainly due to isolation problems associated with high voltage, but also because of limitations in the power electronics. Recent progress in semi-conductor technology enables faster switching and lower costs. The predominant part of prior studies have been directed towards optimising mechanical issues whereas the electro technical part now seem to show great potential for improvement. An overview of flywheel technology and previous projects are presented and moreover a 200 kW flywheel using high voltage technology is simulated. © 2006 Elsevier Ltd. All rights reserved.
Mats Leijon - One of the best experts on this subject based on the ideXlab platform.
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flywheel energy and power storage systems
Renewable & Sustainable Energy Reviews, 2007Co-Authors: Björn Bolund, Hans Bernhoff, Mats LeijonAbstract:For ages Flywheels have been used to achieve smooth operation of machines. The early models where purely mechanical consisting of only a stone wheel attached to an axle. Nowadays Flywheels are complex constructions where energy is stored mechanically and transferred to and from the flywheel by an integrated motor/generator. The stone wheel has been replaced by a steel or composite rotor and magnetic bearings have been introduced. Today Flywheels are used as supplementary UPS storage at several industries world over. Future applications span a wide range including electric vehicles, intermediate storage for renewable energy generation and direct grid applications from power quality issues to offering an alternative to strengthening transmission. One of the key issues for viable flywheel construction is a high overall efficiency, hence a reduction of the total losses. By increasing the voltage, current losses are decreased and otherwise necessary transformer steps become redundant. So far Flywheels over 10Â kV have not been constructed, mainly due to isolation problems associated with high voltage, but also because of limitations in the power electronics. Recent progress in semi-conductor technology enables faster switching and lower costs. The predominant part of prior studies have been directed towards optimising mechanical issues whereas the electro technical part now seem to show great potential for improvement. An overview of flywheel technology and previous projects are presented and moreover a 200Â kW flywheel using high voltage technology is simulated.
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Flywheel energy and power storage systems
Renewable and Sustainable Energy Reviews, 2007Co-Authors: Björn Bolund, Hans Bernhoff, Mats LeijonAbstract:For ages Flywheels have been used to achieve smooth operation of machines. The early models where purely mechanical consisting of only a stone wheel attached to an axle. Nowadays Flywheels are complex constructions where energy is stored mechanically and transferred to and from the flywheel by an integrated motor/generator. The stone wheel has been replaced by a steel or composite rotor and magnetic bearings have been introduced. Today Flywheels are used as supplementary UPS storage at several industries world over. Future applications span a wide range including electric vehicles, intermediate storage for renewable energy generation and direct grid applications from power quality issues to offering an alternative to strengthening transmission. One of the key issues for viable flywheel construction is a high overall efficiency, hence a reduction of the total losses. By increasing the voltage, current losses are decreased and otherwise necessary transformer steps become redundant. So far Flywheels over 10 kV have not been constructed, mainly due to isolation problems associated with high voltage, but also because of limitations in the power electronics. Recent progress in semi-conductor technology enables faster switching and lower costs. The predominant part of prior studies have been directed towards optimising mechanical issues whereas the electro technical part now seem to show great potential for improvement. An overview of flywheel technology and previous projects are presented and moreover a 200 kW flywheel using high voltage technology is simulated. © 2006 Elsevier Ltd. All rights reserved.
Bang Cheng Han - One of the best experts on this subject based on the ideXlab platform.
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Detection of locking protection effect for magnetic bearing flywheel
Guangxue Jingmi Gongcheng Optics and Precision Engineering, 2015Co-Authors: Qiang Liu, Bang Cheng Han, Jian-cheng Fang, Qian Liu, B. C. HanAbstract:©, 2015, Chinese Academy of Sciences. All right reserved. A novel testing method for the protection effect of locking device on a magnetic bearing flywheel was proposed by consideration of the performance of existing locking devices and magnetic bearing Flywheels. By taking a repeated clamping locking device as an example, its protection effect for magnetic bearing Flywheels was evaluated from the performance of magnetic bearing flywheel, vibration macroscopic response and microscopic wear. With comparative analysis on the performance data of the magnetic bearing flywheel and the locking device before and after environmental mechanics tests, they could run normally or not were judged. In the mechanics tests, an acceleration mechanics sensor and an eddy current displacement sensor were respectively used for measuring online response spectra of flywheel system and the vibration displacement between stator and rotor, and for evaluating the macroscopic protection function of the locking device for the flywheel. After mechanics tests, a Scanning Electron Microscopy (SEM) and an Energy Dispersive Spectroscopy (EDS) were applied to analyzing the wear morphology and the spectra of locking surface, and the microscopic protection function was obtained. This testing method provides important significance for detecting of similar aerospace products.
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Simulation of an integrated power/attitude control system with single axis double Flywheels
Xitong Fangzhen Xuebao / Journal of System Simulation, 2006Co-Authors: Bang Cheng Han, Jian-cheng Fang, Y.h. WuAbstract:The utilization of Flywheels to integrated power and attitude control system (IPACS) in satellites to replace traditional chemical batteries and attitude control system has the benefits of increasing reliability, reducing overall weight and spacecraft size, cost. The experimental device of single axis attitude control and energy storage system with two counter rotating Flywheels is designed, and the attitude control is decoupled from DC bus voltage. A computer simulation model of a flywheel energy storage and single axis attitude control system is described in this paper. The goal is to research the control method of energy storage and attitude control use flywheel system, resolve the couple problem between energy storage and attitude control, study the key technology and prepare for the test system. The simulation results demonstrate that it is possible to use two Flywheels to simultaneously provide energy storage while regulating the platform attitude in a single axis.
Joseph Stupak - One of the best experts on this subject based on the ideXlab platform.
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Elastic magnetic composites for energy storage Flywheels
Composites Part B: Engineering, 2016Co-Authors: James E. Martin, Lauren E.S. Rohwer, Joseph StupakAbstract:The bearings used in energy storage Flywheels dissipate a significant amount of energy and can fail catastrophically. Magnetic bearings would both reduce energy dissipation and increase flywheel reliability. The component of magnetic bearing that creates lift is a magnetically soft material embedded into a rebate cut into top of the inner annulus of the flywheel. Because the Flywheels stretch about 1% as they spin up, this magnetic material must also stretch and be more compliant than the flywheel itself, so it does not part from the flywheel during spin up. At the same time, the material needs to be sufficiently stiff that it does not significantly deform in the rebate and must have a sufficiently large magnetic permeability and saturation magnetization to provide the required lift. It must also have high electrical resistivity to prevent heating due to eddy currents. In this paper we investigate whether adequately magnetic, mechanically stiff composites that have the tensile elasticity, high electrical resistivity, permeability and saturation magnetism required for flywheel lift magnet applications can be fabricated. We find the best composites are those comprised of bidisperse Fe particles in the resin G/Flex 650. The primary limiting factor of such materials is the fatigue resistance to tensile strain.
Jian-cheng Fang - One of the best experts on this subject based on the ideXlab platform.
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Detection of locking protection effect for magnetic bearing flywheel
Guangxue Jingmi Gongcheng Optics and Precision Engineering, 2015Co-Authors: Qiang Liu, Bang Cheng Han, Jian-cheng Fang, Qian Liu, B. C. HanAbstract:©, 2015, Chinese Academy of Sciences. All right reserved. A novel testing method for the protection effect of locking device on a magnetic bearing flywheel was proposed by consideration of the performance of existing locking devices and magnetic bearing Flywheels. By taking a repeated clamping locking device as an example, its protection effect for magnetic bearing Flywheels was evaluated from the performance of magnetic bearing flywheel, vibration macroscopic response and microscopic wear. With comparative analysis on the performance data of the magnetic bearing flywheel and the locking device before and after environmental mechanics tests, they could run normally or not were judged. In the mechanics tests, an acceleration mechanics sensor and an eddy current displacement sensor were respectively used for measuring online response spectra of flywheel system and the vibration displacement between stator and rotor, and for evaluating the macroscopic protection function of the locking device for the flywheel. After mechanics tests, a Scanning Electron Microscopy (SEM) and an Energy Dispersive Spectroscopy (EDS) were applied to analyzing the wear morphology and the spectra of locking surface, and the microscopic protection function was obtained. This testing method provides important significance for detecting of similar aerospace products.
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Simulation of an integrated power/attitude control system with single axis double Flywheels
Xitong Fangzhen Xuebao / Journal of System Simulation, 2006Co-Authors: Bang Cheng Han, Jian-cheng Fang, Y.h. WuAbstract:The utilization of Flywheels to integrated power and attitude control system (IPACS) in satellites to replace traditional chemical batteries and attitude control system has the benefits of increasing reliability, reducing overall weight and spacecraft size, cost. The experimental device of single axis attitude control and energy storage system with two counter rotating Flywheels is designed, and the attitude control is decoupled from DC bus voltage. A computer simulation model of a flywheel energy storage and single axis attitude control system is described in this paper. The goal is to research the control method of energy storage and attitude control use flywheel system, resolve the couple problem between energy storage and attitude control, study the key technology and prepare for the test system. The simulation results demonstrate that it is possible to use two Flywheels to simultaneously provide energy storage while regulating the platform attitude in a single axis.
