Abstract
In this paper, a new combined fuzzy observer-based fault-tolerant tracking control scheme is proposed for a doubly fed induction generator (DFIG) based wind turbine (WT) subject to actuator faults. The main contribution consists of the proposal of a novel fault-tolerant fuzzy tracking controller combined with a nominal control law. The control objective is to ensure good state references tracking regardless of the actuator faults effects and simultaneous system state and faults estimation. This later requires the knowledge of the occurrence of actuator faults which are estimated from a Takagi-Sugeno Fuzzy Proportional Integral Observer (T-S FPIO). Within this control scheme, a T-S FPIO has been developed to provide stability tracking error dynamics even the system is subjected to different actuator faults. A compensation term is appended to the composite controller and to ensure robustness against actuator faults. Stability and tracking analysis properties are demonstrated through a quadratic Lyapunov function, which are formulated in terms of Linear Matrix Inequalities (LMIs). The observer gains are determined based on the proposed LMIs stability conditions. A numerical simulation is carried out on a typical 1.5 MW DFIG based WT system to access the effectiveness of the proposed control scheme in comparison to the existing results.