Suppression of a Certain Vehicle Electrical Field and Magnetic Field Radiation Resonance Point

The pulse-width-modulation-controlled inverter and the permanent-magnet synchronous motor are the key electrical components of the electric vehicle (EV). The electromagnetic radiation emission of the motor drive system has a great influence on the electromagnetic radiation emission of the vehicle to a certain extent. Different motor drive systems may have significant differences in the design of the inverter electromagnetic compatibility, the length, and the direction of the cable, which resulting in a significant difference in the radiation emission of the motor drive system. At present, there are many researches on the conduction emission, electromagnetic interference (EMI) modeling, and EMI suppression of the inverter and the motor, but the research on the radiation emission of the motor drive system and its relationship with radiation emission of the vehicle is relatively little. In this paper, a certain EV is taken as an example to analyze the reason why the electric motor drive system is the source of the high emission amplitude in the frequency range from 0.50 to 3 MHz and the resonance point. Also, it is proved that it is feasible to add Y capacitor at inverter's dc terminal. It is effective to reduce the radiation emission of the vehicle in the above frequency range particularly, and a simplified vehicle common-mode interference model is established. Finally, the availability of the model is verified on multiple models.