Design of suboptimal H infinity excitation controllers

This paper presents a method to design suboptimal robust excitation controllers based on H(infinity) control theory. The suboptimal controller results from additional constraints that are imposed on the standard optimal H(infinity) solution. Global stability constraints are incorporated into the H(infinity) algorithm to ensure stability of the interconnected system under decentralized control. Furthermore, a Lyapunov-based index is used to evaluate the robustness properties of the closed loop. In order to obtain a reduced order controller, the method of balanced truncation is used. The suboptimal H(infinity) controllers are output feedback controllers. These controllers posses superior robustness as compared to CPSS and optimal H(infinity) controllers.