Design of Quasi-Halbach Permanent-Magnet Vernier Machine for Direct-Drive Urban Vehicle Application

Removing the gearbox from single-motor configuration of an electric vehicle (EV) would improve motor-to-wheel efficiency by preventing mechanical losses, thus extending autonomy EV. To this end, a permanent-magnet Vernier machine (PMVM) is designed to ensure such operation. This avoids high volume and large pole-pair number armature winding since its operating principle resembles that synchronous with integrated magnetic gear. Therefore, structure achieves low-speed high-torque operation at standard supply frequencies. From specification urban vehicle, required for direct-drive first determined. On basis, initial prototype Machine permanent magnets in rotor can replace traction part (motor + gearbox) sized. uses radial contiguous surface-mounted performance then analyzed using finite element analysis (FEA), showing relatively torque ripple ratio. The are arranged quasi-Halbach simulations performed different stator slot openings ratios tangential magnet order quantify effect each these two quantities terms average torque, ripples harmonics back-electromotive force no load. Since design optimization motor element-assisted, coupling process between FEA Flux software Altair HyperStudy implemented optimization. method has advantages accuracy flux densities electromagnetic estimates, especially ripples. leads value meets specification, along ratio below 5% power factor, while keeping same amount copper.