An interval type-2 fuzzy logic PSS with the optimal H∞ tracking control for multi-machine power system

The aim of this paper is to design a nonlinear robust controller for a multi-machine power system. The optimal H_∞ tracking control combined with the interval type-2 fuzzy logic control as a power system stabilizer is proposed in this study. The type-2 fuzzy logic based on interval value sets is capable for modeling the uncertainty and imprecision and to overcome the drawbacks of the conventional PSS. The optimal H_∞ tracking control guarantees the convergence of the errors to the neighborhood of zero. The objective of the proposed method is to enhance the stability and the dynamic response of the multi-machine power system in different operating conditions. In order to test the effectiveness of the proposed method, the simulation results show the damping of the oscillations of the angle and angular speed with reduced overshoots and quick settling time.