volume | PIER Journals

Abstract

This paper investigates the cogging torque and torque ripple in high pole number interior permanent magnet generators, designed for direct-drive applications. Two interior permanent magnet rotor topologies --- flat-shaped and V-shaped were considered with distributed wound and fractional slot concentrated wound stators. A comparison of torque performances was made between distributed wound and fractional-slot concentrated wound generators. Cogging torque was minimized by finding an optimum magnet pole arc length and torque ripples were minimized by finding optimum slotopening and flux barrier shape. Design analysis was carried out in finite element models. It was found that flat-shaped rotor topology in the fractional slot concentrated wound stator can provide the best torque performance regarding low cogging torque and torque ripple. This finding was verified in constructed prototype machine.

1. Morandin, M., E. Fornasiero, S. Bolognani, and N. Bianchi, "Torque and power rating of a wind- power PM generator drive for maximum profit-to-cost ratio," IEEE Transactions on Industry Applications, Vol. 49, 866-872, 2013.
doi:10.1109/TIA.2013.2244191 Google Scholar

2. Dutta, R., L. Chong, and M. F. Rahman, "Design and experimental verification of an 18-Slot/14- pole fractional-slot concentrated winding interior permanent magnet machine," IEEE Trans. Energy Convers., Vol. 28, 181-190, 2013.
doi:10.1109/TEC.2012.2229281 Google Scholar

3. El-Refaie, A. M., "Fractional-slot concentrated-windings synchronous permanent magnet machines: opportunities and challenges," IEEE Trans. Ind. Electron., Vol. 57, 107-121, 2010.
doi:10.1109/TIE.2009.2030211 Google Scholar

4. Cros, J. and P. Viarouge, "Synthesis of high performance PM motors with concentrated windings," IEEE Trans. Energy Convers., Vol. 17, 248-253, 2002.
doi:10.1109/TEC.2002.1009476 Google Scholar

5. Damiano, A., I. Marongiu, A. Monni, and M. Porru, "Design of a 10MW multi-phase PM synchronous generator for direct-drive wind turbines," Industrial Electronics Society, IECON 2013 --- 39th Annual Conference of the IEEE, 5266-5270, 2013.
doi:10.1109/IECON.2013.6699991 Google Scholar

6. Chang Seop, K. and S. Jin-Soo, "New cogging-torque reduction method for brushless permanent-magnet motors," IEEE Trans. Magn., Vol. 39, 3503-3506, 2003.
doi:10.1109/TMAG.2003.819473 Google Scholar

7. Sopanen, J., V. Ruuskanen, J. Nerg, and J. Pyrhonen, "Dynamic torque analysis of a wind turbine drive train including a direct-driven permanent-magnet generator," IEEE Trans. Energy Convers., Vol. 58, 3859-3867, 2011. Google Scholar

8. Cistelecan, M. V., M. Popescu, and M. Popescu, "Study of the number of slots/pole combinations for low speed permanent magnet synchronous generators," Proc. IEMDC, 1616-1620, 2007. Google Scholar

9. Ge, X., G. Han, Z. Cheng, and Z. Wang, "Research of cogging torque in the brushless DC motor with fractional ratio of slots and poles," Proc. ICEMS, Vol. 1, 76-80, 2005. Google Scholar

10. Wu, D. and Z. Q. Zhu, "Design tradeoff between cogging torque and torque ripple in fractional slot surface-mounted permanent magnet machines," IEEE Trans. Magn., Vol. 51, 1-4, 2015. Google Scholar

11. Sun, A., J. Li, R. Qu, and D. Li, "Effect of multilayer windings on rotor losses of interior permanent magnet generator with fractional-slot concentrated-windings," IEEE Trans. Magn., Vol. 50, 1-4, 2014. Google Scholar

12. Hong, C., Q. Ronghai, L. Jian, and L. Dawei, "Demagnetization performance of a 7 MW interior permanent magnet wind generator with fractional-slot concentrated windings," IEEE Trans. Magn., Vol. 51, 1-4, 2015. Google Scholar

13. Valavi, M., A. Nysveen, R. Nilssen, R. D. Lorenz, and T. Rolvag, "Influence of pole and slot combinations on magnetic forces and vibration in low-speed PM wind generators," IEEE Trans. Magn., Vol. 50, 1-11, 2014.
doi:10.1109/TMAG.2013.2293124 Google Scholar

14. Guemes, J. A., A. A. Iraolagoitia, J. J. Del Hoyo, and P. Fernandez, "Torque analysis in permanent-magnet synchronous motors: A comparative study," IEEE Trans. Energy Convers., Vol. 26, 55-63, 2011.
doi:10.1109/TEC.2010.2053374 Google Scholar

15. Zhu, Z. Q. and D. Howe, "Influence of design parameters on cogging torque in permanent magnet machines," IEEE Trans. Energy Convers., Vol. 15, 407-412, 2000.
doi:10.1109/60.900501 Google Scholar

16. Bianchi, N. and S. Bolognani, "Design techniques for reducing the cogging torque in surface-mounted PM motors," IEEE Trans. Ind. Appl., Vol. 38, 1259, 2002.
doi:10.1109/TIA.2002.802989 Google Scholar

17. Bianchi, N., M. Degano, and E. Fornasiero, "Sensitivity analysis of torque ripple reduction of synchronous reluctance and interior PM motors," IEEE Trans. Ind. Appl., Vol. 51, 187-195, 2015.
doi:10.1109/TIA.2014.2327143 Google Scholar

18. Un-Jae, S., C. Yon-Do, C. Jae-Hak, H. Pil-Wan, K. Dae-hyun, and L. Ju, "A technique of torque ripple reduction in interior permanent magnet synchronous motor," IEEE Trans. Magn., Vol. 47, 3240-3243, 2011.
doi:10.1109/TMAG.2011.2150742 Google Scholar

19. Han, S.-H., T. M. Jahns, W. L. Soong, M. K. Guven, and M. S. Illindala, "Torque ripple reduction in interior permanent magnet synchronous machines using stators with odd number of slots per pole pair," IEEE Trans. Energy Convers., Vol. 25, 118-127, 2010.
doi:10.1109/TEC.2009.2033196 Google Scholar

20. Bianchi, N., S. Bolognani, M. D. Pre, and G. Grezzani, "Design considerations for fractional-slot winding configurations of synchronous machines," IEEE Trans. Ind. Appl., Vol. 42, 997-1006, 2006.
doi:10.1109/TIA.2006.876070 Google Scholar

21. Grop, H., J. Soulard, and H. Persson, "Theoretical investigation of fractional conductor windings for AC-machines --- definition, air-gap m.m.f. and winding factors," Proc. ICEM, 1-6, 2008. Google Scholar

22. Evans, D., Z. Azar, L. J. Wu, and Z. Q. Zhu, "Comparison of optimal design and performance of PM machines having non-overlapping windings and different rotor topologies," IET Proc. PEMD, 1-7, 2010. Google Scholar

23. Islam, M. S., R. Islam, and T. Sebastian, "Experimental verification of design techniques of permanent-magnet synchronous motors for low-torque-ripple applications," IEEE Trans. Ind. Appl., Vol. 47, 88-95, 2011.
doi:10.1109/TIA.2010.2091612 Google Scholar

24. Zhu, Z. Q., "A simple method for measuring cogging torque in permanent magnet machines," Proc. IEEE Conf. PES, 1-4, 2009. Google Scholar

25. Islam, M. S., S. Mir, and T. Sebastian, "Issues in reducing the cogging torque of mass-produced permanent-magnet brushless DC motor," IEEE Trans. Ind. Appl., Vol. 40, 813-820, 2004.
doi:10.1109/TIA.2004.827469 Google Scholar

26. Heins, G., M. Thiele, and T. Brown, "Accurate torque ripple measurement for PMSM," IEEE Trans. Instrumentation and Measurement, Vol. 60, 3868-3874, 2011.
doi:10.1109/TIM.2011.2138350 Google Scholar

Dr. Rukmi Dutta

Dr. Kazi Ahsanullah

Professor Faz Rahman