Research of commonmode voltage elimination for openend winding AC motor drive system

SUN Dan, LIN Bin, YU Jinyun
(College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China)

Abstract: In order to eliminate the commonmode voltage in a single power source openend winding AC motor drive system, the commonmode voltage expression was detevmined by analyzing the openend winding AC motor drive system and the conventional AC motor drive system. A voltage vector selection method was proposed in both direct torque control(DTC) and simplified space vector modulation based direct torque control(SSVMDTC) strategy. In DTC, the method was fulfilled by selecting the corresponding voltage vectors; and in SSVMDTC, the method was realized by proportioning the reference voltage vector properly into two vectors with the same amplitude and 30 degree angle apart from the original vector. The simulation results show that the maximum amplitude of the commonmode voltage has been reduced to near zero and much smaller than the original value, which validates the correctness of the proposed control strategies.
Key words: openend winding machine; commonmode voltage; direct torque control(DTC); simplified space vector modulation(SSVM)