Small Signal Stability Analysis of Switching Dynamical Systems

Integration of power electronic switching systems into electric utility systems and electric motion systems creates the possibility of new instabilities in these systems. The analysis of these systems is a challenging problem since it is difficult to develop a high fidelity analytical model that captures the complex dynamical interaction of these systems. Averaging models often do not provide the required accuracy and therefore they cannot always predict the stability properties of the system. To meet this challenge, a new small signal stability analysis method has been developed. The method is based on computation of the transition matrix over a specified time interval. Since these systems are generally periodic the time interval is selected equal to one cycle of the fundamental frequency. The method is applicable to any system and it is especially suited to switching systems with or without nonlinear elements. In this paper we are interested in systems with PEBB (Power Electronic Building Block)driven motion subsystems (i.e. any type of electric motors). An application example is presented.