Fault-Tolerant System Design for Doubly Salient Electromagnetic Machine Under Loss of Excitation

Aiming at the problem that the traditional doubly salient electromagnetic machine (DSEM) cannot work when the excitation loss occurs, this article designs and analyzes a fault-tolerant DSEM for excitation loss, and the torque ripple suppression strategy under the fault-tolerant operation is studied. First, the characteristics of the output torque of DSEM before and after excitation-loss is analyzed, and a DSEM with a novel winding configuration is proposed to improve the fault tolerance. Second, under normal/excitation-loss conditions, the structure parameters of the fault-tolerant DSEM are analyzed to reveal the influence of the motor structure on its performance. Then, the steady-state torque of the fault-tolerant DSEM is compared with the traditional DSEM and the switched reluctance motor with the same size, which proves the effectiveness of the fault-tolerant design. By analyzing the inductance and torque characteristics, a torque ripple suppression strategy is proposed for the fault-tolerant DSEM without increasing the complexity of the system. Finally, a prototype is developed, and the experimental results verify the fault-tolerant capability of the prototype and the effectiveness of the proposed torque ripple suppression strategy. The research results of this article provide a specific implementation method for the fault-tolerant system design of DSEM under excitation loss.