Component characteristics of Motor Drive System in EV/HEV and its noise spectrum analysis

This paper presents component characteristics of MDS (Motor Drive System) in EV/HEV (Electric/Hybrid Electric Vehicle) and its overall noise spectrum analysis. Basically, MDS is made up of three main components: battery, inverter and motor. The inverter is usually controlled by PWM (Pulse Width Modulation) scheme, and the frequent switching in PWM inverter gives rise to quite a lot of noise in the other components and vice versa. The overall noise spectrum is, of course, heavily dependent on each component in the MDS with its own impedance characteristics: e.g. battery´s frequency-dependent internal impedance makes the voltages quite fluctuated around the load in the multiples of harmonics of inverter switching frequency. That is, we need an exact model for each component in MDS to estimate accurate frequency spectrum data. In this paper, electrical characteristics of five components in MDS of EV/HEV, i.e. battery, LISN, shielded power cable, IGBT, and motor, are investigated in the forepart of this paper, and then the comprehensive spectrum analysis is carried out. Simulated voltage, current and noise spectrum in MDS show qualitatively meaningful results, suggesting that the models used for each component in this paper are valid.