Fuzzy predictive control of the collective pitch in large wind turbines

This paper proposes a new design of a fuzzy predictive controller for collective pitching of large wind turbines. Collective pitch controllers operate in region three to harvest the rated power and maintain the rated speed. The wind turbine model is represented by a Takagi-Sugeno (T-S) fuzzy model. A model predictive collective pitch controller is designed based on the fuzzy model taking into consideration the pitch actuator limits and rates. The proposed controller is coupled with the conventional baseline PI controllers for individual pitch control so as to minimize the moment on the turbine blades. An extended Kalman observer is designed to estimate the immeasurable states. The performance of the proposed fuzzy-predictive controller is compared with a conventional PI controller. Simulation results based on a typical 5-MW offshore wind turbine demonstrate the superiority of the proposed fuzzy-predictive controller.