Designing fuzzy collective pitch controller for variable speed variable pitch large wind turbines via LMI techniques

This paper proposes the design of a fuzzy collective pitch controller (CPC) for large wind turbines. Two types of fuzzy controller are introduced. The design of these controllers relies on the linear matrix inequality (LMI). The performance of the proposed fuzzy controller is compared with a polytopic uncertain controller as found in the literature. The comparison reveals that the proposed controller is superior. Furthermore, the proposed controller is combined with the individual pitch controller (IPC) that reduces the periodic blade´s load. A fuzzy state observer based on LMI techniques is also designed. The proposed observer behavior is compared with that of Kalman observers.