Damping enhancement in power systems using a robust fuzzy sliding mode based PSS controller

This paper proposes the design of power system stabilizer based on fuzzy logic and the sliding mode controller. The control objective is to enhance the stability and to improve the dynamic response of a single-machine power system operating in different conditions. Simulation results show that this control strategy is very robust, flexible and alternative performance. Here, first a sliding-mode controller with an integral operating switching surface is designed. Then a fuzzy sliding mode controller is investigated in which a simple fuzzy inference mechanism is used to estimate the upper bound of uncertainties, and then chattering is reduced. A detailed sensitivity analysis for a one-machine-infinite-bus system reveals that the fuzzy sliding-mode power system stabilizer is quite robust to wide variations in operating load and system parameters.