VP12-09: Design and Investigation of hybrid-tooth dual-winding vernier permanent magnet motor with improved torque performances

Recently, split-tooth vernier permanent magnet (ST-VPM) motors have attracted considerable attention, due to their inherent advantages of high torque density [1]. In this kind of motors, owing to the split-tooth stator structure, motor end winding is reduced, so decreased motor loss and increased efficiency can be realized [2]. However, the split-tooth structure often results in unavoidable flux leakage and magnetic saturation, which limit further enhancement of torque performances. Thus, it has been a hot but challenging issue on how to further improve torque performances of ST-VPM motors. In this paper, a hybrid-tooth dual-winding vernier permanent magnet (HTDW-VPM) motor structure is proposed. The contribution of the proposed motor is presented as follows. Firstly, design principle of hybrid-tooth, which includes split-tooth and straight-tooth, is introduced, which reduces flux leakage and improves torque. In addition, with the assistance of the dual-winding configuration, flux harmonics of different pole pairs can be utilized to contribute to motor output torque. Furthermore, by the purposeful control of inner and outer windings, HTDW-VPM motor can operate during operation modes, which lays a foundation for multi-mode operation. Fig. 1(a) illustrates the structures of the proposed HTDW-VPM motor and the referenced ST-VPM motor. Fig. 1(b) compares the air gap magnetic density and corresponding harmonics distributions. It is observed that the amplitudes of key airgap flux harmonics of the proposed HTDW-VPM motor are higher than the referenced ST-VPM motor. To improve the torque performances of the HTDW-VPM motor, influences of the pole shoe width of both split-tooth and straight tooth are investigated based on the response surface method, as shown in Fig. 1(c). Fig. 2(a) presents flux density and magnetic density distributions of two motors. Fig. 2(b) demonstrates the electromagnetic performance of the two motors under both no-load and load conditions. It is indicated that motor torque is increased by 14.1% and torque ripple is reduced by 71.8% which verifies the reasonability of the proposed HTDW-VPM motor. More simulation and experimental results will be presented in the full paper.References: [1] H. Qu and Z. Q. Zhu, "Analysis of Split-Tooth Stator Slot PM Machine," IEEE Transactions on Industrial Electronics, vol. 68, no. 11, pp. 10580-10591, Nov. 2021, doi: 10.1109/TIE.2020.3031535. [2] L. Fang, D. Li, X. Ren, and R. Qu, "A Novel Permanent Magnet Vernier Machine With Coding-Shaped Tooth," IEEE Transactions on Industrial Electronics, vol. 69, no. 6, pp. 6058-6068, June 2022, doi: 10.1109/TIE.2021.3088331.