Minimization of the cogging torque in stator-PM high-speed flywheel electrical machine

Purpose: This study aims to alleviate the high cogging torque and torque ripple problems of the stator permanent magnet electrical machine (SPMEM) used in the flywheel energy storage system, which result from its double salient structure and high air gap flux density. Design/methodology/approach: First, the theoretical analysis of the cogging torque is carried out, and its generation mechanism is revealed. Then, the optimization approach, based on the parameter optimization and modification of the stator/rotor teeth, is proposed and adopted for the reduction of the cogging torque according to the cogging torque generation mechanism. Finally, the effectiveness of the proposed approach is verified by the finite element analysis. Findings: The analysis shows that the proposed optimization approach (PO-MT), based on the parameter optimization and modification of the stator/rotor teeth, can effectively suppress the cogging torque at a little cost of average output torque in SPMEM, which provides a new way to solve the high cogging torque and torque ripple problems for this kind of machine. Originality/value: In this paper, an optimization approach (PO-MT) based on the parameter optimization and modification of the stator/rotor teeth is proposed to suppress the cogging torque and torque ripple while maintaining high torque performance.