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Wind power generation using an unlimited, natural energy has been getting attention regarding environmental issues in recent years, and the installed capacity of wind power generation system is increasing at a rapid pace, resulting in deterioration of power quality especially in frequency and voltage. This fact will be a big problem in restricting large capacity of wind farms. This paper proposes a new frequency converter: rotary frequency converter (RFC) to moderate the electric output from wind generation, which is to be installed between a set of wind generators and a grid, providing a smoothed electric output, promoting the wind power generation introduction. This mainly consists of a synchronous machine and the adjustable-speed machine. Independent controls of input/output voltage, active power, and reactive power offer electrical separation between the two networks. Experimental study of a prototype model and its characteristics, especially dynamic control, is discussed in this paper. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(4): 26–34, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20922 [ABSTRACT FROM AUTHOR]

Abstract: This paper proposes a technique that determines the optimal windmill operation speed and the optimal rotor flux. Moreover, the position and speed sensor-less wind generation system using the electromotive voltage observer to estimate rotor position and full-order observer to estimate rotor speed and the windmill output torque are proposed. The position and speed sensor-less maximum power point of wind power generation system is controlled by using the above estimated values, optimized windmill operation speed for maximum output power and optimized rotor flux for minimum generator losses. The effectiveness of the position and speed sensor-less maximum power point tracking control for wind power generation system with squirrel cage induction generator is verified by simulations. The simulation results confirm that the proposed method can estimate the operation speed efficiently. [Copyright &y& Elsevier]

There are concerns in regards to wind power generation as its output constantly, as well as considerably, varies. This article presents a control strategy for wind farms consisting of a wind turbine with variable pitch. In order to reduce output power fluctuation of wind farms, smoothed wind-farm output power command is determined by wind condition and fuzzy neural network. In addition, individual wind turbine generators are controlled by output power command derived from wind-farm output power command and coordination control for each wind turbine generator. Simulation results using an actual detailed model for wind-farm systems show the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This paper deals with two types of control method for induction generators used in wind power generating stations. One is aimed at maintaining the voltage of the station node and the other is aimed at maintaining a constant power factor through the branch connecting to the station. Both can be in the controllable area by adjusting the generator reactive power with compensating capacitors. First, theoretical equations for the terminal voltage and power factor of an induction generator are derived, and then the compensating capacitance corresponding to the wind velocity variation is determined quantitatively. By using the proposed control method, it is shown to be possible to maintain the terminal voltage and operating power factor of a wind power generation system at the target values, even when abrupt deviations are caused by wind power disturbances. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(3): 19– 26, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20298 [ABSTRACT FROM AUTHOR]

In recent developments wind power has been gaining rapid usage as an alternative source of electrical power and there is need to formulate optimized control schemes for power generation. This paper presents a sensorless maximum power point tracking control methodology for a wind power generation system. For the sensorless vector control a sliding mode observer is utilized in the estimation of the rotor speed while the rotor position is estimated based on the flux linkage. The Powell method is introduced to improve the efficiency of the permanent magnet synchronous generator (PMSG) d-axis current optimization. To ensure robustness of the proposed paradigm to parameter variations, the windmill loss coefficients determining the optimal rotor speed are identified online. Results of simulations confirm the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Effective utilization of renewable energies such as wind energy instead of fossil fuels is desirable. Wind energy is not constant and windmill output is proportional to the cube of the wind speed, which causes the generated power of wind turbine generators (WTGs) to fluctuate. In order to reduce the output power fluctuation of wind farms, this paper presents an output power leveling control strategy for a wind farm based on both the average wind farm output power and the standard deviation of the wind farm output power, a cooperative control strategy for WTGs, and pitch angle control using a generalized predictive controller (GPC) in all WTG operating regions. Simulation results using an actual detailed model for wind farm systems show the effectiveness of the proposed method. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 158(4): 31– 41, 2007; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/eej.20448 [ABSTRACT FROM AUTHOR]

Abstract: In order to perform maximum power point tracking control of wind generation system, it is necessary to drive windmill at an optimal rotor speed. For that purpose, a rotor position and a wind velocity sensors become indispensable. However, from the aspect of reliability and increase in cost, rotor position sensor and wind velocity sensor are not usually preferred. Hence, wind velocity and position sensorless operating method for wind generation system using observer is proposed in this paper. Moreover, improving the efficiency of the permanent magnet synchronous generator is also performed by optimizing d-axis current using the Powell method. [Copyright &y& Elsevier]

Photovoltaic power generation and wind power generation have an advantage that energy is clean and infinite, but they have a disadvantage in that electrical output energy is unstable, and initial and maintenance costs are expensive. This paper presents an optimal configuration for renewable generating systems in residence using a genetic algorithm (GA). We define that the objective function is the total cost, where the total cost is the sum of initial cost, an operation cost, and a maintenance cost. We determine an optimal configuration of renewable generating systems, where total cost is more reasonable using GA. The simulation using this technique is shown. [ABSTRACT FROM AUTHOR]

Wind energy is not constant and windmill output is proportional to the cube of wind speed, which causes the generated power of wind turbine generators (WTGs) to fluctuate. In order to reduce fluctuation, different methods are available to control the pitch angle of blades of windmill. In a previous work, we proposed the pitch angle control using minimum variance control, and output power leveling was achieved. However, it is a controlled output power for only rated wind speed region. This paper presents a control strategy based on average wind speed and standard deviation of wind speed and pitch angle control using a generalized predictive control in all operating regions for a WTG. The simulation results by using actual detailed model for wind power system show the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Effective utilization of renewable energies such as wind energy as a replacement for fossil fuels is highly desirable. Wind energy is not constant and wind generator output is proportional to the cube of the wind speed, which causes the power output of wind turbine generators (WTGs) to fluctuate. In order to reduce output power fluctuations of wind farms, this paper presents an output power leveling control strategy for wind farms based on both the mean and the standard deviation of wind farm output power, a cooperative control strategy for WTGs, and a pitch angle control method using a generalized predictive controller (GPC) intended for all operating regions of WTGs. Simulation results using an actual detailed model for wind farm systems show the effectiveness of the proposed method. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 154(2): 10–18, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20247 [ABSTRACT FROM AUTHOR]