Abstract
This paper deals with analysis and experiments of an axial flux PM (AFPM) brushless dc motor with minimized cogging torque. Recently, many optimal designs for the AFPM motor have been done by finite element (FE) analysis, but such analysis is time-consuming. In this study, the equation of magnetic flux lines existing between PMs and core is assumed mathematically and the minimum cogging torque is calculated theoretically and geometrically without FE analysis. The form of equation is assumed to be a 2nd order polynomial. The skew angle that makes the cogging torque minimized is calculated theoretically, and the value of minimum cogging torque is compared with the results obtained by FE analysis and experiments. The maximum cogging torque of a proposed AFPM motor has the smallest value approximately at a skew angle of 4° in both the theoretical and FE analysis. Compared with the non-skewed motor, the cogging torque of the skewed motor can be decreased to over 90%, which has a value of 5% of the rated torque. Two types of stator cores, with the skew angle of 0° and 4°, are analyzed, manufactured, and tested experimentally.
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Y. P. Yang, Y. P. Luh and C. H. Cheung, Design and control of axial-flux brushless DC wheel motors for electric vehicles — part I: multi objective optimal design and analysis, IEEE Transactions on Magnetics, 40(4) (2004) 1873–1882.
K. Rahman, N. Patel, T. Ward, J. Nagashima, F. Caricchi and F. Crescimbini, Application of direct drive wheel motor for fuel cell electric and hybrid electric vehicle propulsion system, IEEE IAS Annual Meeting, (2004) 1420–1426.
S. C. Oh and A. Emadi, Test and simulation of axial flux-motor characteristics for hybrid electric vehicles, IEEE Transactions on Vehicular Technology, 53(3) (2004) 912–919.
E. Muljadi, C. P. Butterfield and Y. Wan, Axialflux modular permanent magnet generator with a toroidal winding for wind-turbine applications, IEEE Trans. Ind. Appl., 35(4) (1999) 831–836.
M. Aydin, S. Huang, T. A. Lipo, Torque quality and comparison of internal and external rotor axial flux surface-magnet disc machines, IEEE Trans. Ind. Appl., 53(3) (2006) 822–830.
T. M. Jahns and W. L. Soong, Pulsating torque minimization techniques for permanent magnet AC motor drives-a review, IEEE Trans. Ind. Electron., 43(2) (1996) 321–329.
T. Li and G. Slemon, Reduction of cogging torque in permanent magnet motors, IEEE Transactions on Magnetics, 24(6) (1988) 2901–2903.
D. C. Hanselman, Brushless Permanent-Magnet Motor Design, McGraw-Hill, New York, (1994).
F. Caricchi, F. Capponi, F. Crescimbini and L. Solero, Experimental study on reducing cogging torque and no-load power loss in axial-flux permanent magnet machines with slotted winding, IEEE Trans. Ind. Appl., 40(4) (2004) 1066–1074.
M. Aydin, S. Huang and T. A. Lipo, Torque quality and comparison of internal and external rotor axial flux surface-magnet disc machines, IEEE Trans. Ind. Appl., 53(3) (2006) 822–830.
J. H. Choi, Experimental and Theoretical Analysis of Synchronous PM Planar Motor for Minimized Detent Force, Ph.D. dissertation, Yonsei University, Korea, (2006).
S. Yamamura, Theory of Linear Induction Motors, Second Ed., John Wiley & Sons, (1979).
R. K. Wangsness, Electromagnetic Fields, Second Ed., John Wiley & Sons, (1986).
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This paper was recommended for publication in revised form by Associate Editor Hong Hee Yoo
Dong Ho Kim received B.S. and M.S. degrees in Mechanical Engineering from Pusan National University in 1982 and 1984, respectively. He then received his Ph.D. degree from Yonsei University in 2007. Dr. Kim is currently a Professor at the Department of Automation and Robots at Kyonggi Institute of Technology in Gyeonggi, Korea. His research interests are in the area of production automation.
Jong Hyun Choi received B.S., M.S., and Ph.D. degrees in Mechanical Engineering from Yonsei University, Seoul, Korea, in 1996, 1998, and 2006, respectively. Dr. Choi is currently a post-doctor at the School of Mechanical Engineering at Yonsei University. His research interests are in the area of electromagnetic actuators and magnetic levitation system.
Chang Woo Son received a B.S. from Kyungwon University, Seoul, Korea, in 2006, and his M.S. degree from Yonsei University in 2008, all in mechanical engi-neering. He is currently a research engineer at DA Laboratory of LG Electronics in Seoul, Korea. His research interests are in the area of electromagnetic actuators.
Yoon Su Baek received B.S. and M.S. degrees from Yonsei University, Seoul, Korea, in 1979 and 1981, respectively, and M.S. and Ph.D. degrees from Oregon State University in 1986 and 1990, respectively, all in mechanical engineering. He worked for Samsung Heavy Industry Ltd. as head research engineer at Mechatronics Research Center from 1990 to 1993. Dr. Baek is currently a Professor at the School of Mechanical Engineering at Yonsei University. His research interests are motion devices and robotics, especially relating to multi-D.O.F. actuators. He is also interested in magnetic brake and levitation system.
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Kim, D.H., Choi, J.H., Son, C.W. et al. Theoretical analysis and experiments of axial flux pm motors with minimized cogging torque. J Mech Sci Technol 23, 335–343 (2009). https://doi.org/10.1007/s12206-008-0814-x
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DOI: https://doi.org/10.1007/s12206-008-0814-x