This paper studies the impact of current harmonics on the synchronous reluctance machine's average torque and torque ripple. The electromagnetic model of a general m-phase synchronous reluctance machine which integrates the inductance and current harmonics is developed. This model shows that there exist two mechanisms that generate an average torque with a non-zero average value: the proper contribution of the current harmonics and the interaction between them. This model is then used in the case of a 2-phase synchronous reluctance machine with a common transversally laminated anisotropic rotor. This machine design shows negligible inductance harmonics with respect to its fundamental value. Therefore, it has been found that the interaction between the 3rd and 5th current harmonics generates a torque equivalent to the torque generated by the fundamental current component. A locus of the current harmonic components that deliver a constant torque is determined. Furthermore, we have found that, on this locus, the machine torque ripple decreases significantly. Experimental data validate the developed theoretical work and show that at the same torque, the torque ripple is reduced from 20% to 4%.
2. Barcaro, M., N. Bianchi, M. Guarnieri, and P. Alotto, "Optimization of interior pm motors with machaon rotor flux barriers," IEEE Trans. Magn., Vol. 47, No. 5, 958-961, 2011.
3. Bolognagni, S., D. Bon, P. M. Dai, and N. Bianchi, "Torque harmonic compensation in a synchronous reluctance motor," IEEE Trans. Energy Convers., Vol. 23, No. 2, 466-473, June 2008.
4. Bolognagni, S., D. Bon, P. M. Dai, and N. Bianchi, "Rotor flux-barrier design for torque ripple reduction in synchronous reluctance and PM-assisted synchronous reluctance motors," IEEE Trans. Ind. Appl., Vol. 45, No. 3, 921-928, 2009.
5. Vagati, A., G. Pellegrino, E. Armando, P. Guglielmi, and B. Boazzo, "Multipolar ferrite-assisted synchronous reluctance machines: A general design approach," IEEE Trans. Ind. Electron., Vol. 62, No. 2, 832-845, 2015.
6. Tutelea, L. N., L. Parsa, D. Dorrell, and I. Boldea, "Automotive electric propulsion systems with reduced or no permanent magnets: An overview," IEEE Trans. Ind. Electron., Vol. 61, No. 10, 5696-5711, October 2014.
7. Xu, B., L. Cai, and H. Guan, "Low-cost ferrite PM-assisted synchronous reluctance machine for electric vehicles," IEEE Trans. Ind. Electron., Vol. 61, No. 10, 5741-5748, October 2014.
8. Faiz, J. and I. Tabatabaei, "Extension of winding function theory for nonuniform air gap in electric machinery," IEEE Trans. Magn., Vol. 38, No. 6, 3654-3657, November 2002.
9. Kamper, M. J., S. Gerber, and E. Howard, "Flux barrier and skew design optimisation of reluctance synchronous machines," 2014 Int. Conf. on Electrical Machines (ICEM), 1186-1192, September 2014.
10. Ikaheimo, J., et al., "Synchronous high-speed reluctance machine with novel rotor construction," IEEE Trans. Ind. Electron., Vol. 61, No. 6, 2969-2975, June 2014.
11. Hsieh, M. F., H. F. Kuo, M. C. Tsai, and I. Lin, "Improved accuracy for performance evaluation of synchronous reluctance motor," IEEE Trans. Magn., No. 99, 1-1, 2015.
12. Magnussen, F., C. Sadarangani, and R. R. Moghaddam, "Theoretical and experimental reevaluation of synchronous reluctance machine," IEEE Trans. Ind. Electron., Vol. 57, No. 1, 6-13, January 2010.
13. Magnussen, F., C. Sadarangani, and R. R. Moghaddam, "Novel rotor design optimization of synchronous reluctance machine for low torque ripple," 20th Int. Conf. Electrical Machines (ICEM), 720-724, September 2012.
14. Moghaddam, R.-R. and F. Gyllensten, "Novel high-performance SynRM design method: An easy approach for a complicated rotor topology," IEEE Trans. Ind. Electron., Vol. 61, No. 9, 5058-5065, September 2014.
15. Ooi, S., Y. Inoue, M. Sanada, and S. Morimoto, "Experimental evaluation of a rare-earth-free PMASynRM with ferrite magnets for automotive applications," IEEE Trans. Ind. Electron., Vol. 61, No. 10, 5749-5756, October 2014.
16. Neti, P. and S. Nandi, "Determination of effective air-gap length of synchronous reluctance motors (SynchRel) from experimental data," IEEE Trans. Ind. Appl., Vol. 42, No. 2, 454-464, March 2006.
17. Kim, S. I., J. P. Hong, J. H. Lee, and J. M. Park, "Rotor design on torque ripple reduction for a synchronous reluctance motor with concentrated winding using response surface methodology," IEEE Trans. Magn., Vol. 42, No. 10, 3479-3481, October 2006.
18. Hiramto, K., S.Morimoto, Y. Takeda, and M. Sanada, "Torque ripple improvement for synchronous reluctance motor using asymmetric flux barrier arrangement," Conf. Rec. Industry Applications Conf. 38th IAS Annu. Meeting, Vol. 1, 250-255, October 2003.
19. Schmitz, N. L., Introductory Electromechanics, Ronald Press, 1965.
20. Faiz, J., H. Lesani, M. T. Nabavi-Rzavi, and I. Tabatabaei, "Modeling and simulation of a salientpole synchronous generator with dynamic eccentricity using modified winding function theory," IEEE Trans. Magn., Vol. 40, No. 3, 1550-1555, 2004.
21. Tessarolo, A., "Accurate computation of multiphase synchronous machine inductances based on winding function theory," IEEE Trans. Energy Convers., Vol. 27, No. 4, 895-904, 2012.
22. Tessarolo, A., et al., "On the analytical estimation of the airgap field in synchronous reluctance machine," 2014 Int. Conf. on Electrical Machines (ICEM), 239-244, September 2014.
23. Mezzarobba, M., M. Degano, and A. Tessarolo, "Analytical calculation of air-gap armature reaction field including slotting effects in fractional-slot concentrated-coil SPM multiphase machines," Int. Conf. Power Engineering, Energy and Electrical Drives (POWERENG), 1-6, 2011.
24. Rahimian, M., T. A. Lipo, and H. Toliyat, "DQ modeling of five phase synchronous reluctance machines including third harmonic of air-gap MMF," Conf. Rec. IEEE Industry Applications Society Annu. Meeting, Vol. 1, 231-237, September 1991.
25. Waikar Shailesh, P., A. Lipo Thomas, and H. A. Toliyat, "Analysis and simulation of five-phase synchronous reluctance machines including third harmonic of airgap MMF," IEEE Trans. Ind. Appl., Vol. 34, No. 2, 332-339, March 1998.
26. Vas, P., Electrical Machines and Drives: A Space-vector Theory Approach, Vol. 25, Oxford University Press on Demand, 1992.
27. Villet, W. T. and M. J. Kamper, "Variable-Gear EV reluctance synchronous motor drives; An evaluation of rotor structures for position-sensorless control," IEEE Trans. Ind. Electron., Vol. 61, No. 10, 5732-5740, October 2014.
28. Wang, K., et al., "Optimal slot/pole and flux-barrier layer number combinations for synchronous reluctance machines," 8th Int. Conf. and Exhibition on Ecological Vehicles and Renewable Energies (EVER), 1-8, March 2013.
29. Liu, T. H. and M. Y. Wei, "Design and implementation of an online tuning adaptive controller for synchronous reluctance motor drives," IEEE Trans. Ind. Electron., Vol. 60, No. 9, 3644-3657, September 2013.
30. Xu, L., "Rotor structure selections of nonsine five-phase synchronous reluctance machines for improved torque capability," IEEE Trans. Ind. Appl., Vol. 36, No. 4, 1111-1117, July 2000.
31. Henaux, C., M. Fadel, S. Desharnais, L. Calegari, and S. Yammine, "Synchronous reluctance machine flux barrier design based on the flux line patterns in a solid rotor," 2014 Int. Conf. on Electrical Machines (ICEM), 297-302, September 2014.
32. Hock Beng Foo, G., D. M. Vilathgamuwa, D. L. Maskell, and X. Zhang, "An improved robust fieldweakeaning algorithm for direct-torque-controlled synchronous-reluctance-motor drives," IEEE Trans. Ind. Electron., Vol. 62, No. 5, 3255-3264, 2015.