Analysis and mitigation of reflected wave voltages and currents in WBG devices based motor drives

Abstract

In inverter based motor drives, the fast switching speeds of the power devices along with the cable, result in overvoltage at the motor end. Corresponding to the overvoltage at the motor end, there are currents at the inverter end. While the overvoltage increases the stress on motor and insulation, the load parasitics along with the cable increases the switching loss of the power devices. These effects are more pronounced in converters using WBG devices because of faster switching times. Previous works have only studied either over-voltages & currents in 2-L converters. The 2-L converters have low source and high load impedances. This work involves the study of the effect of inductive source impedance and RC terminal network on the reflected wave phenomenon and the switching loss of the device. Simulation and experimental results are shown to verify the analysis.