Multi‐level optimisation design of a yoke‐less axial‐field flux‐switching permanent magnet motor considering the fault‐tolerant capability

Abstract This paper proposes a multi‐level optimisation design strategy aimed at enhancing the fault‐tolerant capability of a Yoke‐less Axial‐Field Flux‐Switching Permanent Magnet (YASA‐AFFSPM) motor. The research addresses the crucial requirement for robustness and reliability in electric motor systems utilised in safety‐critical applications. By employing a comprehensive multi‐objective optimisation approach, the motor's design is refined at three levels based on the main effect stratification of design variables for the YASA‐AFFSPM motor. The design variables are divided into three levels and optimised, resulting in the attainment of a comprehensive optimal solution that considers multiple design goals, including average torque, cogging torque, and fault‐tolerant capability. The optimal design places a primary emphasis on attaining a substantial level of fault tolerance for both open‐ and short‐circuit faults. This is accomplished by reducing the ratio of mutual‐inductance to self‐inductance. To streamline optimisation, the Kriging model approximates finite element analysis at each level. Furthermore, the effectiveness of the design is showcased through the utilisation of a dual‐channel winding configuration. A prototype is constructed, and experimental validation demonstrates a significant improvement in fault‐tolerance performance, with results indicating enhancements of 14% in average torque and 41% in cogging torque.