Design of a Novel Torque‐Angle Approximation Permanent Magnet Synchronous Reluctance Machine for Electric Vehicles

ABSTRACT To improve the torque performance of permanent magnet synchronous reluctance machine (PMSRM) for electric vehicles, a novel torque‐angle approximation PMSRM (TAA_PMSRM) is proposed in this article. This design utilises asymmetric permanent magnets (PMs) and inter‐pole cavity to shift the axis of PM magnetic field, so as to make the peak of the PM torque component approximate to the peak of the reluctance torque component, and to increase the resultant torque without increasing the cost. And asymmetric tangential ribs are introduced to suppress torque ripple effectively. Through the parameter sensitivity analysis, the specific influence of the key structure parameters related to the PM magnetic field shift on the electromagnetic performance of the TAA_PMSRM is clarified, providing a theoretical basis for torque performance optimisation. Based on the step‐by‐step multi‐objective optimisation design, the average torque and torque ripple are optimised while ensuring the mechanical integrity of rotor. A comparative analysis between the proposed TAA_PMSRM and the conventional PMSRM, both optimised using the same method under multiple operating conditions, confirms the torque improvement and overall performance advantages of the proposed design. Finally, a prototype of the TAA_PMSRM is fabricated and tested to validate the simulation accuracy and demonstrate its practical performance benefits.