Damping controller design for power systems using LMI and GA techniques

In this paper, a novel damping controller with a simple structure, is designed based on the (infinity)optimal control method for power system stabilizer (PSS) in multimachine area. The parameters of the proportional integral (PI) controller are tuned to mimic the robust performance of the decentralized one. More specifically, genetic algorithms (GAs) optimization is used to obtain the control parameters of the (PI) controller subject to the (infinity)constraints in terms of linear matrix inequalities (LMI). Hence, this control design is called GALMI. A global controller is designed by reduced centralized controller based on minimum communicated information to coordinate the local decentralized controllers. Another global controller, which is more appealing from an implementation point of view, is designed based on two level PSS to damp both local and interarea modes. Objective function is presented using GA to allow the selection of the stabilizer parameters. The effectiveness of the suggested techniques in damping local and interarea modes of oscillations in multimachine power systems is verified under various operating conditions to demonstrate their robust performance.