Stability Improvement of V/f Control Scheme with Active Damping for Small Capacitor IPMSM Drive System

The small film capacitor has been utilized in interior permanent magnet synchronous motor (IPMSM) drive system due to longer lifetime and smaller volume compared with electrolytic capacitor. However, the stability margin of IPMSM drive system with small capacitor under V/f control scheme is very low, which is discussed in detail by modeling the system in this paper. In order to improve stability, an active damping technique is proposed, which can be realized by injecting an active damping voltage term to the setting voltage vector. Simulation and experimental results using a 1500W, 380Vrms, 1500rpm IPMSM and small film capacitor drive system are obtained for verifying the effectiveness of V/f control scheme with proposed active damping technique.