Fault-Tolerant Control Strategy for Doubly Salient Electromagnetic Machine Based on Current Profile Function Under Loss of Excitation

The doubly salient electromagnetic machine (DSEM) has broad application prospects in fields such as electric vehicles and aviation, which puts higher requirements on its reliability. Fault-tolerant control is one of the effective ways to improve the reliability of the DSEM. At present, there are few studies on fault-tolerant control when excitation faults occur. This article proposes a fault-tolerant control strategy based on the current profile function for the DSEM drive systems with excitation faults. First, the current commutation process is optimized to suppress torque ripple based on the torque and current variation characteristics of the DSEM under loss of excitation. Then, the distribution ratio of the three-phase currents that minimize the instantaneous copper loss of the armature windings is derived for the current noncommutation process. On this basis, a three-phase current profile function is designed, which is combined with torque closed-loop control to reduce torque ripple. Finally, the experiments on an 18/12 pole DSEM system are performed to validate the effectiveness of the proposed fault-tolerant control method, which can reduce the torque ripple and improve the torque–ampere ratio.