On the Design of Variable Structure Load Frequency Controllers by Tabu Search Algorithm: Application to Nonlinear Interconnected Models

Abstract

A variable structure controller (VSC) with chattering reduction feature applied to interconnected load frequency control (LFC) problem is presented. Formulating the design of VSC as an optimization problem and utilizing tabu search (TS) algorithm provides a simple and systematic way of arriving at the optimal feedback gains and switching vector values of the controller. In addition, this will cut down the need for nonlinear or coordinate transformation as reported before. The tested interconnected LFC model incorporates nonlinearities in terms of generation rate constraint (GRC) and a limiter on the integral control value. In order to guarantee the enhancement of the system, dynamical performance and chattering reduction of the VSC, different objective functions were investigated in the optimization process. In addition, the complexity of the controller is reduced by using only the accessible states in designing the VSC. Comparison with previous LFC methods reported in literature validates the significance of the proposed VSC design. Keywords: load frequency control (LFC)nonlinear modelstabu search algorithms (TS)variable structure control (VSC) The authors would like to acknowledge the support of King Fahd University of Petroleum and Minerals.