Electric Vehicle HV-DC EMC Filter Loss due to Variations in AC-Load Configuration

The motor of an electric vehicle is connected to the inverter either by cables or busbars if the inverter and motor are integrated in the same housing. Instead of a motor, an equivalent lumped load may be used during EMC pre-compliance testing. Utilizing a SPICE-based simulation model, the conducted emissions of an electric vehicle powertrain are investigated with different AC-load configurations. Shielded AC-cables lead to increased parasitic inductance and capacitance on the AC side of the powertrain. On the HV-DC side of the inverter, EMC filters are required to comply with conducted emissions limits. The filter components, especially those filtering the common mode, are exposed to power loss due to the noise currents on the powertrain. Simulation results for AC-cable lengths 0-3m show that the power loss in the EMC filter components shows a strong dependency on cable length.