Effect of Switching Frequency on Efficiency in Wide Bandgap Based Drive Systems

This paper investigates the effect of switching frequency on the losses occurring in the inverter and motor of an electric vehicle throughout the WLTC. A combination of analytical and numerical methods are used to model the conduction and switching losses in the inverter, and the copper and iron losses in the motor. Iron losses are derived from a Steinmetz model. The Tesla Model 3 is used as a reference vehicle to size the drive system. For the selected drive system parameters, the switching frequencies that minimise the overall system losses for $\mathbf{S i}, \mathbf{S i C}$, and GaN based inverters are found. The reduction in switching losses of SiC and GaN over Si result in an increase in the optimum switching frequency, from 4 kHz to 11 kHz and 20 kHz respectively.