The Intelligent Control Method Study of Variable Speed Wind Turbine Generator

Pitch control by controlling the pitch angle of the wind wheel blade of the wind turbine generator can control the rotation speed when the wind turbine generator is starting and the output power when the wind turbine generator is on grid. The wind wheel can get maximum wind energy when its blade tip speed ratio is an optimum value. When wind speed is less than the rated speed, the rotation speed of the wind turbine generator system should be controlled in order to get the optimum blade tip ratio. When wind speed is larger than the rated speed, the output power must be also controlled by changing the pitch angle of the blade according to the wind speed or the wind turbine will be damaged because of the over load. To get the maximum output power under lower wind speed and to maintain the stable rated output power under higher wind speed, the proper method must be used. In classical control, the controller design needs the accurate mathematical model of the wind turbine generator system, but this model is very difficult to get. To solve this problem, we use fuzzy controller to trace the maximum power when wind speed is lower than the rated speed and use neural network to get the proper pitch angle and so to limit the output power when the wind speed is greater than the rated speed. The simulation block diagram and simulation results were obtained. Compared with the PID controller, intelligent controller has better anti-interference property. The fluctuation of the power is minimized, the maximum power is traced and the rated power is maintained.