On discussion of switching frequency impacts on DC-fed motor drive EMI filter design

This paper initiated a discussion on the motor drive switching frequency and its impact on EMI filter design for power density point of view. The paper analyses EMI noise characteristics with increasing switching frequency in DC-fed three-phase motor drive systems, which result in different filter parameters. Nevertheless increasing switching frequency also brings in differences on volt-second across the magnetic and high frequency loss in the magnetic components and interconnections. This change also influence on the filter size and weight. Several EMI filter designs at different switching frequency are compared and efforts are made to give a picture of power density barriers for EMI filters for DC-fed motor drive systems.