This paper addresses a control methodology to enhance stability and voltage regulation for the existing power systems with conventional PSS and AVR equipments. The control design problem is reduced to find a new control loop including a simple fixed gain vector. In order to optimal tuning of gain elements, the problem is formulated via an H∞ static output feedback (H∞ -SOF) control technique, and the solution is easily carried out using a developed iterative linear matrix inequalities (ILMI) algorithm. A single machine infinite-bus system example is given to illustrate the developed approach. The results of The proposed control strategy are compared with conventional PSS design. The robust controller is shown to maintain the robust performance and minimize the of disturbance properly.
