Comparative Study of Pitch Angle Control for Variable Speed Wind Turbine

Abstract

Pitch angle control is commonly used method for regulating the output torque of the wind energy system whenever wind speed is exceeding base speed and other variables like wind speed, generator speed and generator power can also be selected for control. According to wind turbine power versus speed curve, generator dynamic characteristics of wind turbine system get varied. But it is essential to retain the generator speed at the ideal one despite such deviations. As PI (proportional–integral) controller is conventionally used as controller for pitch angle control, for this mathematical model of system must be already known. In this work, conventional PI controller, fuzzy logic controller and neural network based controller are implemented and their results are compared in terms of peak overshoot, settling time and offset error. The system knowledge is not required for fuzzy logic and neural network based pitch angle controller and non-linearity like wind turbulence can be easily modelled using these controllers. The simulation result shows that the neural network gives better result as compared to PI controller and fuzzy logic controller.