Robust controller design for small-signal stability enhancement of power systems

The paper proposes a technique for designing a robust power system stabilizer that combines H_infin optimal control with the bilinear transformation. The bilinear transformation is used to prevent the pole-zero cancellation phenomenon inherent in the H_infin mixed sensitivity design and to assign dominant poles at desired locations in the s-plane. The technique is applied to design a power system stabilizer for a single machine connected to an infinite bus. The proposed controller is compared with both a conventional lead-lag controller and a controller design based on an evolutionary algorithm called PBIL (population based incremental learning). Frequency and time domain simulations are presented to demonstrate the effectiveness of the proposed design approach