EMC filters in high voltage traction drive systems

Recent and future traction concepts for vehicles comprise electric drives. The traction system with its topology implemented within the vehicle has to be considered as an electromagnetic interference (EMI) source with different coupling paths. EMC concepts have to be defined to limit the EMI levels to tolerable limits as required by existing EMC standards. EMC measures at the power electronic level as well as shielding of cables, boxes and input/output filters have to be considered. The topic deserves even more attention because the working voltages in traction systems are increased far beyond the well investigated 28 V/42 V levels to the voltage range between 400 and 900 VDC. The paper discusses various EMC aspects of a traction drive system with a 600 VDC link and introduces a new common-mode choke with magnetic bypass.