Fault-Tolerant Control of Doubly Salient Brushless DC Motor Drive under Open-Circuit Faults

Doubly salient brushless dc (DSBLDC) motor drive system has attracted increasing attention due to the rugged rotor structure, brushless operation and low cost. The switch open-circuit (OC) fault increases the torque ripple and decreases the maximal output power of DSBLDC motor drive system. A fault-tolerance control strategy for switch OC circuit is proposed in this study. The back electromotive force (BEMF) current would occur in a pulse-width modulation (PWM) pattern. It severely degrades the proposed method's fault-tolerant performance. So the cause of the BEMF current is analysed and BEMF current is suppressed by specific PWM pattern. Finally, the fault-tolerance control strategy is verified by experiment results and the selection PWM pattern is proved to be correct and practical.