A Diagnosis Method for Inverter Single Power Switch Open Circuit Fault of Doubly Salient Electromagnetic Motor

The inverter fault diagnosis technology is a key technology to improve the reliability of doubly salient electromagnetic motor (DSEM) drive systems. For the problems of slow diagnosis speed, high diagnosis cost and influence by load variation in traditional fault diagnosis methods, this paper proposes a single switch open circuit fault diagnosis method for DSEM inverters, which requires only one current sensor. Firstly, the change of the current path before and after the power switch fault is analysed to obtain the change of the drive signal and bus current as well as the relationship between bus current and phase current. Secondly, the fault location is achieved by changing the operating mode of the motor. Furthermore, in order to shorten the fault diagnosis time, the minimum time for each operating mode to operate is given by combining the circuit states. Finally, simulations of faults are used to verify the effectiveness of the proposed method.