volume | PIER Journals

Abstract

This paper presents an exact analytical method to compute the air-gap magnetic field of surface-mounted permanent-magnet (SMPM) motors for evaluating slotting effects accurately. Solution field regions are divided into air-gap domain, permanent magnet (PM) domain, and slot domains. The Laplace's equations or Poisson's equations of the sub-domains are contacted by boundary conditions and then solved by exact analytical method. The actual height of slot and distance between slots are taken into account in the computation. Magnetic field distributions and cogging torque computed with the proposed analytical method are compared with those issued from 2-D finite-element method (FEM), and the comparison results are consistent and show the correctness and effectiveness of the proposed analytical method.

1. Noyal Doss, A., R. Brindha, K. Mohanraj, S. S. Dash, and K. M. Kavya, "A novel method for cogging torque reduction in permanent magnet brushless DC motor using T-shaped bifurcation in stator teeth," Progress In Electromagnetics Research M, Vol. 66, 99-107, 2018.

2. Onsal, M., B. Cumhur, Y. Demir, E. Yolacan, and M. Aydin, "Rotor design optimization of a new flux assisted consequent pole spoke-type permanent magnet torque motor for low-speed applications," IEEE Trans. Magn., Vol. 54, No. 11, ID: 8206005, 2018.

3. Xie, K. F., D. W. Li, R. H. Qu, and D. Jiang, "Analysis and experimental comparison of spoke type and surface-mounted PM machines with fractional slot concentrated winding," 2016 19th International Conference on Electrical Machines and Systems (ICEMS), 1-6, 2016.

4. Zhou, Y., H. Li, and G. Meng, "Analytical calculation of magnetic field and cogging torque in surface-mounted permanent-magnet machines accounting for any eccentric rotor shape," IEEE Trans. Ind. Electro., Vol. 62, No. 6, 3438-3447, 2015.

5. Zhao, N. N. and W. G. Liu, "Loss calculation and thermal analysis of surface-mounted PM motor and interior PM motor," IEEE Trans. Magn., Vol. 51, No. 11, ID: 8112604, 2015.

6. Kumar, P., M. M. Reza, and R. K. Srivastava, "Analytical method for calculation of cogging torque reduction due to slot shifting in a dual stator dual rotor permanent magnet machine with semi-closed slots," Progress In Electromagnetics Research M, Vol. 70, 99-108, 2018.

7. Jing, L. B., R. H. Qu, W. B. Kong, D. Li, and H. L. Huang, "Genetic-algorithm-based analytical method of SMPM motors," 2017 IEEE International Electric Machines and Drives Conference (IEMDC), 1-6, 2017.

8. Tiang, T. L., D. Ishak, C. P. Lim, and M. Rezal Mohamed, "Analytical method using virtual PM blocks to represent magnet segmentations in surface-mounted PM synchronous machines," Progress In Electromagnetics Research B, Vol. 76, 23-36, 2017.
doi:10.2528/PIERB17041501

9. Zhu, Z. Q., D. Howe, and E. Bolte, "Instantaneous magnetic field distribution in brushless permanent magnet DC motors, Part I: Open-circuit field," IEEE Trans. Magn., Vol. 29, No. 1, 124-135, 1993.
doi:10.1109/20.195557

10. Zhu, Z. Q. and D. Howe, "Instantaneous magnetic field distribution in brushless magnet DC motors, Part III: Effect of stator slotting," IEEE Trans. Magn., Vol. 29, No. 1, 143-151, 1993.
doi:10.1109/20.195559

11. Zarko, D., D. Ban, and A. L. Thomas, "Analytical calculation of magnetic field distribution in the slotted air gap of a surface permanent-magnet motor using complex relative air-gap permeance," IEEE Trans. Magn., Vol. 42, No. 7, 1828-1837, 2006.
doi:10.1109/TMAG.2006.874594

12. Pahlavani, M. A. and H. R. Gholinejad Omran, "A new analytical description and FEA validation of an effective method to reduce the cogging torque in SM-AFPM motors," Progress In Electromagnetics Research M, Vol. 42, 189-197, 2015.
doi:10.2528/PIERM15051504

Dr. Libing Jing

Dr. Junlin Chen

Dr. Zhangxian Huang

Dr. Jun Gong