The Study of CM EMI Cancellation in Inverter Based on Compensation Principle

Because of the special limitation to the ground capacitance in inverter, it´s difficult to cancel the serious common-mode noise and the ground current for using large CM filter. In this paper a passive cancellation method for CM EMI in power electronic converter is introduced. This new technique canceling EMI just needs a compensating transformer winding and a compensating capacitor. Since the different structures of the devise result in different paths of CM noise, two EMI compensate ways were chose to compensating the main noise in inverter. This paper also discussed the factors inference the high-frequency compensation issues and give effective solutions. Simulation and experimental results approved good effects of these cancellation techniques