Analytical investigation of DC link overvoltages during freewheeling for inverters in EV

摘要

When a fault occurs in an electric drive system one of the default reaction from the system is to turn off the IGBTs so that the machine and inverter are isolated. But the current continues to flow through the freewheeling diodes causing an overvoltage in the DC capacitor. This paper discusses an analytical method to calculate and predict the overvoltages in the Inverter for an electric machine drive during freewheeling, using stator currents and voltages. The output from the analytical model is verified using measurements.