关键词：线性矩阵不等式（LMI）；电力系统稳定器（PSS）；鲁棒控制
摘 要：H_2 and H_∞ optimal control are two important breakthroughs in modern robust control. In recent years, the H_2 and H_∞ controller design techniques have gained a lot of research attention. Both have strong theoretical basis and are efficient algorithms for synthesizing optimal controllers. The performance of H_2 robust controller is useful to handle stochastic aspects such as measurement noise and capture the control cost. In the robust H_2 approach, the controller is designed to minimize an upper bound on the worst case H_2 norm for a range of admissible plant perturbations. When a model under analysis is applied with H_2 robust controller, the closed loop system will have a good dynamic system performance, but it has poor robustness for the external disturbances of the uncertain system model. The performance of H_∞ is convenient to enforce robustness to model uncertainty, but it is based on compromising system performance. Their combination, the mixed H_2/H_∞ allows intuitive quadratic performance specifications of the H_2 synthesis with robust stability requirements specifications expressed by the H_∞ synthesis. In time domain aspects, satisfactory time response and closed loop damping can often be achieved by enforcing the closed loop poles into a predetermined region of the left half plane. Combining these requirements to form so-called mixed H_2/H_∞ design with regional pole placement constraints allows for more flexible and accurate specification of closed-loop behavior. This chapter introduces the work of design of improved LMI-based robust output feedback controller and related simulations.