Research on Single Power Switch Open Circuit Fault Diagnosis of Doubly Salient Eletromagnetic Motor Based on Bus Current

Inverter is a weak link in the doubly salient electromagnetic motor (DSEM) drive system. After failure, the system runs in an unbalanced state, and the whole system may be damaged after a long time of operation. In this paper, a single power switch open circuit fault diagnosis method based on bus current is proposed for DSEM inverter with PWM modulation in both upper and lower bridge arms. Firstly, the fault detection is realized by the bus current is 0, and the phenomenon of false diagnosis is eliminated by setting the time threshold. Then, the fault location is realized by comparing whether the bus current is the same before and after the power switch of the current working sector is turned off. Compared with the existing methods, the proposed method has low diagnosis cost, short diagnosis time and does not need to change the inverter topology. Finally, the effectiveness of the proposed method is verified by fault simulation experiments.