Improved sliding mode control law for wind power systems

This paper develops a new nonlinear control law that outperforms the traditional sliding mode control law especially the suppression of the chatter phenomenon. This new controller design is an extension of the conventional sliding mode control law by transforming the sliding surface into a sliding sector which is divided into sliding sub-surfaces that define its boundaries. The fuzzy logic introduced by Takagi–Sugeno is integrated into this proposed controller instead of the traditional logic. This new control law will be applied to the two-mass model of the mechanical part of the wind power system to capture the maximum wind energy, minimize the vibrations of the shaft caused by the random fluctuation of the wind speed, maintain better performance in terms of stability demonstrated by the robust Lyapunov criterion, and reject the chatter phenomenon. The results of this new strategy are compared with both the traditional sliding mode control law and the recent switching sector control law and are illustrated by simulation results using MATLAB software.