Design of a 35kW Permanent Magnet Synchronous Motor for Electric Vehicle Equipped with Nonuniform Airgap Rotor

This paper presents a successful design of a 35kW nonuniform airgap permanent magnet synchronous motor (PMSM) developed for electric vehicles. Nonuniform airgap rotor periphery making airgap length maximize at the quadrature axis and minimize at the direct axis is employed to reduce harmonics of the airgap flux density and no-load back EMF. Systematic analysis, including pole-arc coefficient, air gap ratio, stator configuration and slot type, is used on the proposed motor by finite element analysis. Finite element analyses highlight advantages of the designed nonuniform airgap PMSM by comparing with conventional PMSM. In order to further verify the rationality of the structure and ensure the safe and reliable operation of the motor, multi-physical field analysis is applied to nonuniform airgap PMSM.