Optimization of PM Segments Shift Angles for Minimizing the Cogging Torque ‎of YASA-AFPM Machines Using Response Surface Methodology

Document Type : Research paper

Author

Electrical Engineering Department, Faculty of Engineering, Yasouj University, Yasouj, Iran

Abstract

Mitigating the cogging torque is an important issue in designing the YASA machines. The main aim of the paper is to optimize an efficient technique to mitigate the cogging torque of YASA machines. In the suggested technique, the permanent magnets (PMs) are segmented into several segments in the radial direction, and then these PM segments are shifted at appropriate angles in the peripheral direction. The proposed PM segmentation method is compared with the conventional PM segmentation as well as the conventional PM skewing approaches in terms of the amount of cogging torque reduction and the amount of negative impact on the generator load-ability. It is shown that compared to the other two studied approaches, the proposed method is more effective in reducing cogging torque and at the same time, has a less negative impact on the generator output power. Using the suggested technique and via several finite elements based simulations, it is shown that without causing a significant negative impact on the generator load-ability, the generator cogging torque can be reduced considerably (about 90%). By implementing the RSM (Response Surface Methodology), optimal shift angles of the PM segments (factors) are determined to mitigate the cogging torque and maintain the generator load-ability. The experiments are carried out based on the RSM, as an important topic in the statistical DOE (Design of Experiments) approach, to study the impacts of PM segments shift angles on the output power and cogging torque of the YASA-AFPM generator. All of the experimental samples are extracted via the FEA simulations. Also, some of the simulation results are verified using the experimental tests. 

Keywords


[1]  J. Kim, W. Choi and B. Sarlioglu, “Closed-form solution for axial flux permanent-magnet machines with a traction application study”, IEEE Trans. Ind. Appl., vol. 52, pp. 1775-84, 2016.
[2]  Z. Zhang, W. Geng, Y. Liu and C. Wang, “Feasibility of a new ironless-stator axial flux permanent magnet machine for aircraft electric propulsion application”, CES Trans. Electr. Mach. Syst., vol. 3, pp. 30-38, 2019.
[3]  N. Anitha and R. Bharanikumar, “Design and analysis of axial flux permanent magnet machine for wind power applications”, Proc. PETPES, Mangalore, India, 2019.
[4]  P. Ojaghlu and A. Vahedi, “Specification and design of ring winding axial flux motor for rim-driven thruster of ship electric propulsion”, IEEE Trans. Veh. Technol., vol. 68, pp. 1318-26, 2019.
[5]  T. Woolmer and M. McCulloch, “Analysis of the yokeless and segmented armature machine”, Proc. IEMDC, Antalya, Turkey, 2007.
[6]  L. Xu et al., “Optimal design and electromagnetic analysis of yokeless and segmented armature machine based on finite-element method and genetic algorithm”, Proc. ITEC Asia-Pacific, Harbin, China, 2017.
[7]  A. EL-Refaie, “Fractional-slot concentrated-windings synchronous permanent magnet machines: opportunities and challenges”, IEEE Trans. Ind. Electron., vol. 57, pp. 107-121, 2010.
[8]  B. Rocandio, “Design and analysis of fractional-slot concentrated-winding multiphase fault-tolerant permanent magnet synchronous machines”, Ph.D. dissertation, University of Navarra, Pamplona, Spain, 2015.
[9]  J. Ji, H. Chen and W. Zhao, “Reduction of eddy current loss of permanent-magnet machineswith fractional slot concentrated windings”, Prog. Electromagn. Res. Lett., vol. 56, pp. 39-46, 2015.
[10]  T. Gundogdu and G. Komurgoz, “Investigation of winding MMF harmonic reduction methods in IPM machines equipped with FSCWs”, Int. Trans. Electr. Energy Syst., pp. 1-27, 2018.
[11]  J. Li, R. Qu, Y. Cho and D. Li, “Reduction of eddy-current losses by circumferential and radial PM segmentation in axial flux permanent magnet machines with fractional-slot concentrated winding”, Proc. INTERMAG, Beijing, China, 2015.
[12]  J. Li et al., “Minimization of cogging torque in fractional-slot axial flux permanent magnet synchronous machine with conventional structure”, Proc. ICEF, Dalian, Liaoning, China, 2012.
[13]  S. Ho, S. Niu and W. Fu, “Design and comparison of vernier permanent magnet machines”, IEEE Trans. Magn., vol. 47, pp. 3280-83, 2011.
[14]  A. Kumari, S. Marwaha and A. Marwaha, “Comparison of methods of minimization of cogging torque in wind generators using FE analysis”, J. Indian Inst. Sci., vol. 86, pp. 355-362, 2006.
[15]  M. Gulec and M. Aydin, “Magnet asymmetry in reduction of cogging torque for integer slot axial flux permanent magnet motors”, IET Electr. Power Appl., vol. 8, pp. 189-198, 2014.
[16]  L. Jia et al., “Dual-skew magnet for cogging torque minimization of axial flux PMSM with segmented stator”, IEEE Trans. Magn., vol. 56, 2020.
[17]  J. Gao et al., “Cogging torque reduction by elementary-cogging-unit shift for permanent magnet machines”, IEEE Trans. Magn., vol. 53, pp. 1-4, 2017.
[18]  E. Aycicek, N. Bekiroglu and S. Ozcira, “An experimental analysis on cogging torque of axial flux permanent magnet synchronous machine”, Proc. Natl. Acad. Sci., India, Sect. A Phys. Sci., vol. 86, pp. 95-101, 2016.
[19]  L. Xiao et al., “Cogging torque analysis and minimization of axial flux PM machines with combined rectangle-shaped magnet”, IEEE Trans. Ind. Appl., vol. 53, pp. 1018-1027, 2017.
[20]  P. Kumar, M. Reza and R. Srivastava, “Effect of cogging torque minimization techniques on performance of an axial flux permanent magnet machine”, Proc. ITEC-India, Pune, India, 2017.
[21]  M. Aydin and M. Gulec, “Reduction of cogging torque in double-rotor axial-flux permanent-magnet disk motors: a review of cost-effective magnet-skewing techniques with experimental verification”, IEEE Trans. Ind. Electron., vol. 61, pp. 5025-34, 2014.
[22]  O. Ocak and M. Aydin, “A new variable step skew approach for minimizing torque pulsations in permanent magnet synchronous motors”, Proc. INTERMAG, Singapore, 2018.
[23]  J. Kim, Y. Li, E. Cetin and B. Sarlioglu, “Influence of rotor tooth shaping on cogging torque of axial flux-switching permanent magnet machine”, IEEE Trans. Ind. Appl., vol. 55, pp. 1290-98, 2019.
[24]  L. Xu, Y. Xu and J. Gong, “Analysis and optimization of cogging torque in yokeless and segmented armature axial-flux permanent-magnet machine with soft magnetic composite core”, IEEE Trans. Magn., vol. 54, pp. 1-5, 2018.
[25]  A. Patel and B. Suthar, “Double layer magnet design technique for cogging torque reduction of dual rotor single stator axial flux brushless DC motor”, Iran J. Electr. Electron. Eng., vol. 16, pp. 58-65, 2020.
[26]  Y. Wang et al., “Reduction of magnet eddy current loss in PMSM by using partial magnet segment method”, IEEE Trans. Magn., vol. 55, pp. 1-5, 2019.
[27]  S. Arand and M. Ardebili, “Multi-objective design and prototyping of a low cogging torque axial-flux PM generator with segmented stator for small-scale direct-drive wind turbines”, IET Electr. Power Appl., vol. 10, pp. 889-899, 2016.
[28]  D. Hanselman, Brushless permanent magnet motor design, Ohio: Magna Physics Publishing, 2006.
[29]  T. Li and G. Slemon, “Reduction of cogging torque in PM motors”, IEEE Trans. Magn., vol. 24, pp. 2901-03, 1988.
[30]  N. Rostami, “Comprehensive parametric study for design improvement of a low-speed AFPMSG for small scale wind-turbine”, J. Oper. Autom. Power Eng., vol. 7, pp. 58-64, 2019.
[31]  D. Habibinia, M. Feyzi and N. Rostami , “A new method for computation of axial flux permanent magnet synchronous machine inductances under saturated condition”, J. Oper. Autom. Power Eng., vol. 6, pp. 208-217, 2018.
[32]  D. Gonzalez, J. Tapia and A. Bettancourt, “Design consideration to reduce cogging torque in axial flux permanent-magnet machines”, IEEE Trans. Magn., vol. 43, pp. 3435-40, 2007.
[33]  S. Arslan, E. Kurt, O. Aki̇zu and J. Lopez-guede, “Design optimization study of a torus type axial flux machine”, J. Energy Syst., vol. 2, pp. 43-56, 2018.
[34]  J. He et al., “Optimization of permanent-magnet spherical motor based on taguchi method”, IEEE Trans. Magn., vol. 56, pp. 1-7, 2020.
[35]  H. Moghaddam, A. Vahedi and S. Ebrahimi, “Design optimization of transversely laminated synchronous reluctance machine for flywheel energy storage system using response surface methodology”, IEEE Trans. Ind. Electron., vol. 64, pp. 9748-57, 2017.
[36]  S. Saha, G. Choi and Y. Cho, “Optimal rotor shape design of LSPM with efficiency and power factor improvement using response surface methodology”, IEEE Trans. Magn., vol. 51, pp. 1-4, 2015.
[37]  S. Sun, F. Jiang, T. Li and K. Yang, “Optimization of cogging torque in a hybrid axial and radial flux permanent magnet machine”, Proc. ICEMS, Harbin, China, 2019.
[38]  M. Uy and J. Telford, “Optimization by design of experiment techniques”, Proc. IEEE Aero Conf., Big Sky, MT, 2009.
[39]  D. Montgomery, Design and Analysis of Experiments: Response surface method and designs, New Jersey: John Wiley and Sons, 2005.
[40]  A. Khyri and J. Cornell, Response Surfaces: Designs and Analyses, New York: Marcel Dekker, 1996.
[41]  B. Khuri, Response Surface Methodology and Related Topics, New Jersey: World Scientific Pub Co Inc, 2006.