Masaya Ichinose

Output Power Smoothing and Hydrogen Production by Using Variable Speed Wind Generators

This paper presents a combination system of wind energy conversion and hydrogen production. Hydrogen is expected as an alternative energy source in the future, and this is the best way to produce it from renewable energy like wind energy. On the other hand, the output of a wind generator, in general, fluctuates greatly due to wind speed variations, and thus the output fluctuations can have a serious influence on the power system operation. In the proposed system, a variable speed wind generator is adopted, and an electrolyzer is installed in parallel with it for hydrogen production. Output power from the wind generator is smoothed and supplied to the power system as well as to the electrolyzer based on the cooperative control method. The performance of the proposed system is evaluated by simulation analyses, in which simulations are performed by using PSCAD/EMTDC.

Efficiency calculation of wind turbine generation system with doubly-fed induction generator

This paper presents a method to calculate various losses in wind turbine generation system (WTGS) as a function of wind speed, which is based on the steady state analysis. Variable speed WTGS using a doubly-fed induction generator (DFIG) and power converters (inverter and converter) is mainly considered in this paper. By using the proposed method, wind turbine power, generated power, generator losses, gearbox loss, power converter losses and energy efficiency can be calculated quickly. Moreover, annual energy production and capacity factor of the wind farm can be obtained by using the wind speed characteristic expressed by Weibull distribution function. Therefore, if the Weibull distribution function of wind speed is available, we can calculate the annual energy production without using real annual wind speed data. Using the data of Weibull distribution function of some different areas, capacity factor of each area is calculated and compared with those of other types of WTGSs such as Permanent Magnet Synchronous Generator (PMSG) and Squirrel-Cage Induction Generator (IG).

A Calculation Method of the Total Efficiency of Wind Generator

This paper presents a method to represent various losses in wind generator as a function of wind speed, which is based on the steady state analysis. By using the proposed method, wind turbine power, generated power, copper loss, iron loss, stray load loss, mechanical losses and energy efficiency can be calculated quickly. Calculation was done using a wind speed data expressed by Probability Density Function in order to predict capacity factor and total efficiency of a wind farm for one year. Finally it is concluded that the proposed prediction calculation method is effective, and can contribute to a wind generator design and construction planning of a wind farm.

Development of an Advanced Microturbine System Using Humid Air Turbine Cycle

A prototype machine for a next generation microturbine system applying a simple humid air turbine system (design target of electrical output: 150 kW, electrical efficiency: 35% LHV) was developed for its laboratory evaluation. A low NOx combustor which applied a lean-lean zone combustion concept and water lubricated bearings were developed for the prototype machine. Operation using two water lines for the humid air turbine (HAT) was proposed as an effective way to obtain rated electric output to ambient temperature of 40 deg C. Tests for the main components were done successfully. Motoring tests, full speed test with no load, 50% load and 70% load tests as preliminary tests for rated load tests were also carried out successfully. Low NOx emission of 7.6 ppm and high efficiency of 95.6% for the power conversion system were achieved in the partial load tests. At the first rated load test without HAT and Water atomizing inlet air cooling (WAC) that followed those partial load tests, 150.3 kW electric output with electrical efficiency of 32% was obtained.© 2004 ASME

Development of a 150kw Microturbine System Which Applies the Humid Air Turbine Cycle

A prototype machine for a next generation microturbine system incorporating a simplified humid air turbine cycle has been developed for laboratory evaluation. Design targets of electrical output were 150 kW and of electrical efficiency, 35% LHV. The main feature of this microturbine system was utilization of water for improved electrical output, as lubricant for bearings and as coolant for the cooling system of the generator and the power conversion system Design specifications without WAC (Water Atomizing inlet air Cooling) and HAT (Humid Air Turbine) were rated output of 129 kW and efficiency of 32.5% LHV. Performance tests without WAC and HAT were done successfully. Electrical output of 135 kW with an efficiency of more than 33% was obtained in the rated load test. Operation tests for WAC and HAT were carried out under the partial load condition as preliminary tests. Water flow rates of WAC were about 0.43 weight % of inlet air flow rate of the compressor and of HAT, about 2.0 weight %. Effects of WAC and HAT were promptly reflected on electrical output power. Electrical outputs were increased 6 kW by WAC and 11kW by HAT, and efficiencies were increased 1.0 pt % by WAC and 2.0 pt % by HAT. Results of WAC and HAT performance tests showed significant effects on the electrical efficiency with an increase of 3.0 point % and electrical output with an increase of 20% by supplying just 2.4 weight % water as the inlet air flow rate of the compressor.Copyright

A cooperative control method for output power smoothing and hydrogen production by using variable speed wind generator

This paper presents a combination system of wind energy conversion and hydrogen production. Hydrogen is expected as alternative energy sources in the future, and it is the best way to produce it from renewable energy like wind energy. On the other hand, the output of a wind generator, in general, fluctuates greatly due to wind speed variations, and thus the output fluctuations can have a..serious influence on the power system. In the proposed system, a variable speed wind generator is adopted, and an electrolyzer is installed in parallel with it for hydrogen production. Output power from the wind generator is smoothed and supplied to the power system as well as to the electrolyzer based on the cooperative control method. The performance of the proposed system is evaluated by simulation analyses, in which simulations are performed by using PSCAD/EMTDC.

A new wind generation system cooperatively controlled with hydrogen electrolyzer

This paper presents a cooperative control method of the wind generation system composed of multiple wind genera1tors and hydrogen generator. In this system, some part of the output power from the wind generators is consumed by hydrogen generator, and the other part, which is smoothed by the cooperative control between the wind generators and the hydrogen generator, is supplied to the grid. In this system, Doubly-Fed Induction Generator (DFIG) is adopted as a wind generator, which can be operated at adjustable speed. Each electrolyzer in the hydrogen generator is operated only at the rated power consumption mode (“ON condition”) or at zero power consumption mode (“OFF condition”), because fractional power operation can have a bad influence on the service life of electrolyzers. Therefore, since the hydrogen generator cannot smooth the fluctuating power from the wind generators completely, the smoothing control is performed by controlling the kinetic energy of DFSGs in this system. As a result, in the proposed system, smoothed power can be supplied to the grid system without using any energy storage device as well as hydrogen can be produced.

A Wind-Power Generation System Having a Function of Suppressing Line Voltage Deviation

Wind-power generation (WPG) tends to create voltage deviation in the distribution lines because wind speed always fluctuates. This paper proposes to add a new function to the interface converter of WPG, that is, generation of reactive power to suppress the voltage deviation caused by WPG itself. This paper also proposes a reactive power control strategy for the interface converter to suppress the voltage deviation. The validity is verified by simulation studies

Continuous operation control during electric power network faults in an adjustable speed generation system with a flywheel excited by a DC link converter

For an adjustable speed generation system with a flywheel, not only quick active power and voltage responses, but also continuous operation during electric power network faults are necessary to stabilize electric power networks. Quick active power response of 40 rad/s and voltage response of 40 rad/s are obtained in a 30 kVA test model. To realize these quick responses, a controller with multi-microprocessors is used, in which the minimum sampling time is 185 /spl mu/s. Moreover, cooperative power flow control between the rectifier and inverter is added to power, voltage and speed controls of the generator/motor. Chopper control for overvoltage suppression is added to the DC link voltage control. Continuous operation can be realized even during such electric power network faults as 1-line, 2-line and 3-line ground faults due to these controls.