Parameter tuning of fixed structure controller for power system stability enhancement

This paper presents a new method to design fixed-structure controllers for enhancing stability of power systems. Generally, in a robust control design, high-order dynamical controllers are obtained by solving a convex optimization problem. However, it is difficult to implement the high-order robust controllers in existing control devices such as SVC and PSS. We show that a robust controller design subject to constraints on the controller structure can be formulated as a BMI problem. Then, we propose a successive approximation algorithm to solve the BMI problem. The algorithm is based on solving linear matrix inequalities from initial conditions obtained by particle swarm optimization. Using a simple model with weakly damped interarea power oscillation modes, we verify that a proposed algorithm is practically useful.