A Fault Diagnosis and Fault-Tolerant Control Method for Open-Circuit Fault of Excitation Winding Converter in DSEM Drive System

Abstract

This article proposes a fault location and fault-tolerant control method for the open-circuit fault of the excitation winding converter in the doubly salient electromagnetic motor (DSEM) drive system. First, by rearranging the placement of the excitation current sensor and analyzing the change characteristics of the sampled current values before and after the excitation winding converter open-circuit fault, the faulty switch is quickly located. Then, fault-tolerant control strategies for the armature winding and excitation winding converter are designed for open-circuit faults in the excitation winding converter switches at different locations. This ensures that the output torque of the DSEM remains unchanged before and after fault-tolerant control, thus guaranteeing smooth motor operation. Simultaneously, the switching moment of the armature winding converter control strategy is optimized after the occurrence of the excitation winding converter open-circuit fault, in order to prevent the motor from outputting negative torque during the switching process. The proposed method can rapidly locate the faulty switch in the excitation winding converter without the need for additional sensors. It ensures that the motor maintains a consistent output torque before and after fault-tolerant operation, thereby guaranteeing the load-carrying capability of the motor. Finally, experiments conducted on a 12/8 three-phase DSEM verify the effectiveness and practicality of the proposed method.