Switching over technique to fault tolerant function of DC-bus battery in dual inverter motor drive

Abstract

The dual inverter motor drive feeding an open-end winding PM motor is focused on for mileage improvement and autopilot technologies of hybrid and electric vehicles. Autopilot operation requires the fault tolerant functions which achieve to keep controlling the motor, even if some failure occurs in the system. In this paper, the fault tolerant function of the DC-bus battery in the dual inverter motor drive system is discussed. The system has a battery and a capacitor across the DC-bus of each inverter. The capacitor is utilized to keep operating the motor, instead of the failed battery in the fault tolerant function. In this time, however, it is necessarily to control the capacitor voltage of the failed side inverter at constantly with the space vector modulation (SVM). In particular, it is required to regulate the capacitor voltage of the failed inverter at a half of the battery voltage of the normal condition inverter. Therefore, the capacitor voltage must be discharged immediately after some failure is occurred in the battery of one of the inverters. In this paper, the switching over techniques from the normal condition to the fault tolerant function is proposed, and the proposed technique is examined through several computer simulations.