Common mode impedance shaping choke to attenuate the conducted EMI in three phase drive

Abstract

This paper presents an impedance shaping technique to reshape the common mode (CM) impedance profile of three phase common mode choke. The CM impedance offered by a designed CM choke with specific core area and number of turns is reshaped using CMIS choke. CM noise in a two level voltage source inverter (TL-VSI) has dominant frequency components near inverter switching frequency (Fsw). Attenuation of these dominant frequency components demand high impedance at Fsw. A designed CMIS choke offers high CM impedance for Fsw compared to CCM choke. The proposed three phase CMIS choke is a passive CM noise attenuation technique that attenuates the dominant Fsw components. The CM attenuation performance of passive EMI filter with CMIS choke and CCM choke are compared for TL-VSI.