Fuzzy control used in variable speed wind turbine

Control of wind turbine generator system is very complicated because of the fluctuation and intermittence of wind speed and the complexity of power electronics. In classical control, the controller design needs accurate mathematical model, but this kind of model of the wind turbine generator system is very difficult to get because of the nonlinear characteristics. In order to obtain the maximum wind energy below rated wind speed, maintaining the optimum blade tip speed ratio is needed. In order to enhance the flexibility of gear system and get stable output power above rated wind speed, storing or delivering some energy in this condition is required. Using fuzzy controller, can simplify and avoid the sophisticated mathematical model. The fuzzy relations between the variables and the fuzzy rules were stated in detail. Simulation model and results are obtained. By using fuzzy controller, wind turbine generator system has better anti-interference property compared with the PID controller. The fluctuation of the power is minimized, the maximum power is traced and the rated power is maintained. The robust and stability of the designed fuzzy controller is also simply verified.