Stability and Stabilization for T–S Fuzzy Load Frequency Control Power System With Energy Storage System

This article investigates the stability and stabilization problem for delay-dependent Takagi–Sugeno (T–S) fuzzy load-frequency control (LFC) power system with energy storage system (ESS). First, a unified T–S fuzzy LFC model is constructed for power system with ESS by further analyzing the nonlinear characteristics existing in turbine and governor dynamics. Second, a fuzzy proportional-integral control strategy is proposed to stabilize the T–S fuzzy power system. Then, based on existing approaches to handle quadratic function with respect to the time-varying delay, an improved quadratic function negative-determination lemma is proposed to achieve larger upper bound of time delay. Furthermore, delay-dependent stability criteria with less conservatism are established by means of Lyapunov stability theorem. Finally, some contrast illustrative examples are given to verify the advantage of the proposed methods.