volume | PIER Journals

Abstract

To cut rare-earth consumption and suppress cogging torque of conventional symmetrical pole permanent magnet generators (PMGs), this paper presents a low-rare-earth composite asymmetric pole topology with hybrid NdFeB-ferrite magnets. The magnetic field modulation of permanent magnet magnetomotive force (MMF) is analyzed, and an energy-method cogging torque formula is derived to elaborate the flux-improving and torque-reducing mechanism of asymmetric poles. Equivalent magnetic circuit and finite element models are built, followed by stratified sensitivity analysis of structural parameters. Taking high induced electromotive force (EMF), low EMF THD, and small cogging torque as targets, magnet arc angle is optimized via an evolutionary algorithm coupled with TOPSIS; magnet width and thickness are further optimized for optimal cost-performance. After optimization, EMF fundamental amplitude rises; EMF THD and cogging torque drop; and NdFeB usage falls by 8.56%. Prototype tests verify the simulation accuracy. The hybrid magnet scheme saves rare-earth materials and enhances overall generator performance.

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Dr. Yanhong Gao

Dr. Huihui Geng

Dr. Xingzhe Pang

Dr. Wenyu Li

Dr. Junfeng Wang

Dr. Xin Zhou

Dr. Xingxv Jin