Design of parameters in static synchronous compensator with indirect current control based on the system stability

Based on the small-signal dynamic model of the indirect current control, a design method of the interface inductor and the DC side capacitor of static synchronous compensator (STATCOM) is proposed. The design method bases on the system stability. This paper presents the models of two types of indirect current control (phase-shift control, phase and amplitude control). In the phase-shift control, the design relationship of the interface inductor and the DC side capacitor is obtained by using the pole-zero map. In the phase and amplitude control, an analysis of the influences of parameters on the current control loop and the voltage control loop is obtained by using the transfer functions and the bode diagrams. The parameters which have a small influence on the system stability are ignored. The equation of the phase margin is simplified. Then, this paper proposes the design methods of the interface inductor and the DC side capacitor. Finally, simulation and experimental results verify the above dynamic model and the design methods.