H∞-controllers for linearised time-delay power systems

Three H∞-control schemes are developed for the stabilisation of power-system models with state delays. Two control schemes which consist of one gain term representing pure state feedback are proposed first. Then, a controller consisting of two gain terms comprising pure plus delayed state feedback is developed. The proposed controllers guarantee the asymptotic stability of the controlled system and the H∞-norm bound of the closed-loop transfer function of the system. The associated gains are determined in each case from the solution of a linear-matrix-inequality feasibility problem. Simulation results of the proposed schemes are presented and discussed.