Inverter Power Device Fault Detection and Fail Safe Action Strategy for Electric Vehicle With a Dual Inverter Fed Open Winding Motor

Abstract

A electric vehicle (EV) needs high drive system efficiency, low motor noise and limp-home capability of the traction drive when there is a component failure. A dual inverter fed open winding interior permanent magnet synchronous motor (DIF-OW-IPMSM) drive system satisfied all the above needs. In this paper, new algorithms for the inverter power device fault detection and fail-safe action strategy for the DIF-OW-IPMSM drive system in the entire speed region of the EV are proposed to prove its high reliability. The new algorithms for the inverter power device fault detection are derived from the sensed three phase fault currents and their subsequent analytical and logical processing within the micro-computer. The fail-safe action strategy is derived such that the unbalanced three phase fault currents using the dual inverters are quickly restored to balanced three phase currents using a single inverter and hence, the effect of the vibration of the traction motor due to undesired torque ripple during inverter device fault condition is kept minimum. The proposed new algorithms are verified by suitable simulation and experimental results, and the safe limp-home capability of the DIF-OW-IPMSM drive system is demonstrated.