Comparison and analysis of permanent magnet vernier motors for low-noise in-wheel motor application

In this study, the permanent magnet vernier motors (PMVMs) with different external rotor topologies are investigated and compared to obtain the optimal topology, which can reduce the vibroacoustic noise and keep the excellent output performance. Firstly, the unipolar and bipolar PMVM motors with V-shape magnets are designed based on the torque and cost of the consequent-pole PMVM (CPMVM), which have the reduced unbalanced magnetic force (UMF). Then to evaluate the performances of PMVMs comprehensively, the characteristics including flux density, back-electromotive force, torque, the electromagnetic force and acoustic noise etc., are quantitatively investigated and compared by the finite element analysis (FEA). Finally, the modal parameters and acoustics noise spectrum of CPMVM are tested and compared with the noise FEA results, which verify the V-shape magnet PMVMs can reduce the UMF and low-frequency noise level by maintaining the output performance.