Design a Unified Power Flow Controller (UPFC) Using Bilinear Sliding Mode Control Method

In this paper, at first, a new model will be attained for unified power flow controller (UPFC) using state space equation of bilinear systems. Then, a complete novel method of designing UPFC controllers will be represented by the use of variant structure systems. In this method, input signals of UPFC are designed through sliding mode controller. In order to design these kinds of controllers, at first, control rules are obtained by the use of designing four different slide levels and then setting their derivatives (which express dynamics of the flows of axes d and q, in serial and parallel transformers) to zero. In fact, applying the outputs of this controller to UPFC is equal to bring the flows of axes d and q to the reference value in both UPFC. In the other hand, internal dynamics (DC capacitor voltage) will be stabilized in UPFC by means of PI controller. The stability of the system is obtained through Lyapunov function.