The Experts below are selected from a list of 267 Experts worldwide ranked by ideXlab platform
W U Yihui - One of the best experts on this subject based on the ideXlab platform.
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simulation of a integrated power attitude control system with single axis double Flywheels
Computer Simulation, 2006Co-Authors: W U YihuiAbstract:The utilization of Flywheels to integrated power and attitude control system (IPACS) in satellites to replace traditional chemical batteries and attitude control system have 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 on 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.
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 The stone wheel has been replaced by a steel or composite rotor and magnetic bearings have been introduced.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.
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.
Björn Bolund - 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.
Yu. M. Tarnopol'skii - One of the best experts on this subject based on the ideXlab platform.
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Spin-tests of composite Flywheels. A review
Mechanics of Composite Materials, 1997Co-Authors: I. M. Zaitsev, G. G. Portnov, Yu. M. Tarnopol'skiiAbstract:Spin-test results are given for two types of composite Flywheels, namely, molded disks and rim-type Flywheels with chordwise wrapping. The models differend in form, size, and material. Dynamic problems associated with Flywheel spinning-up, ultimate peripheral speeds, and the limiting energy-storing capacities are described. Results are also given for full-scale Flywheel tests. Dynamic problems were shown to be the governing factors for rim-type Flywheels.