A mixed procedure based on classical and modern control to design robust damping controllers

A systematic mixed procedure based on classical and robust control techniques is proposed in this work for the design of robust low-order damping controllers. The procedure formally guarantees a robust performance index for the system in closed-loop by employing a minimum performance index associated with a robust control technique. The mixed approach aims at providing an acceptable and easy-to-use robust design procedure as well as controllers with a simple and typical structure. Besides, a great variety of mathematical tools for the analyses and design of control systems may be employed in the overall procedure. The tests and results have shown that the overall procedure is suitable for the oscillation problem in power systems and that the resulting controllers are robust and effective in the damping of low-frequency electromechanical oscillations.