Abstract：The most accurate method to design the stator coreless axial flux permanent magnet machine is the 3D finite-element analysis, which is exceedingly time-consuming. To solve this problem, this paper presents an analytical design method. Firstly, the analytical model of the 3D no-load magnetic field distribution of the machine is proposed. Analytical expressions of the back electromotive force of the machine are derived based on the model by using the winding function method. Inductance and resistance are calculated based on parameters such as the estimated ending connection length. Machine losses are analyzed in detail and analytical equations of them are presented. Then equations for the steady state performance are derived bases on the equivalent circuit of the machine. Finally the proposed design method is applied to three prototype machines with different rate powers and winding configurations. The prototype machines were tested and the calculated results are compared with the experimental ones, showing good agreements.
[1] Gieras J F, Wang R J, Kamper M J. Axial flux permanent magnet brushless machines[M]. Berlin: Springer, 2008. [2] Gieras J F. Advancements in electric machines[M]. Berlin: Springer, 2008. [3] Lombard N F, Kamper M J. Analysis and performance of an ironless stator axial flux PM machine[J]. IEEE Transactions on Energy Conversion, 1999, 14(4): 1051-1056. [4] Kamper M J, Wang R J, Rossouw F G. Analysis and performance evaluation of axial flux air-cored stator permanent magnet machine with concentrated coils[C]. IEEE International Electric Machines and Drives Conference, 2007: 13-20. [5] Bumby J R, Martin R. Axial-flux permanent-magnet air-cored generator for small-scale wind turbines[J]. IEE Proceedings Electrical Power Applications, 2005, 152(5): 1065-1075. [6] Azzouzi J, Barakat G, Dakyo B. Quasi-3D analytical modeling of the magnetic field of an axial flux permanent magnet synchronous machine[C]. IEEE International Electric Machines and Drives Conference, 2003: 1941-1947. [7] Choi J Y, Lee SH, Ko K J, et al. Improved analytical model for electromagnetic analysis of axial flux machines with double-sided permanent magnet rotor and coreless stator windings[J]. IEEE Transactions on Mangetics, 2011, 47(10): 2760-2763. [8] Gair S, Canova A, Eastham, et al. A new 2D FEM analysis of a disc machine with offset rotor[C]. Proceedings of the International Conference on Power Electronics, Drives and Energy Systems for Industrial Growth, 1996: 617-621. [9] Cvetkovski G, Petkovska L, Cundev M, et al. Quasi 3D FEM in function of an optimization analysis of a PM disk motor[C]. Proceedings of the 14th International Conference on Electrical Machines, 2000: 1871-1875. [10] Kreyszig E. Advanced engineering mathematics[M]. New York: Wiley, 2011. [11] Zhu Z Q, Howe D, Bolte E, et al. Instantaneousmagnetic field distribution in brushless permanent magnet DC motors, part I: open-circuit field[J]. IEEE Transactions on Magnetics, 1993, 29(1): 124-135. [12] Lipo T. Analysis of synchronous machines, course notes for ECE 511[R]. Wisconsin: University of Wisconsin, 1995. [13] 陈世坤. 电机设计[M]. 北京：机械工业出版社, 2000. [14] Carter G. The electromagnetic field in its engineering aspects[M]. London: Longmans, 1954. [15] Pyrhönen J, Jokinen T, Hrabovcová V. Design of rotating electrical machines[M]. Chichester: Wiley, 2008. [16] Saari J. Thermal analysis of high-speed induction machines[D]. Espoo: Helsinki University of Technology, 1998. [17] Honsinger V B. Performance of polyphase permanent magnet machines[J]. IEEE Transactions on Power Apparatus and Systems, 1980, 99(4): 1510-1516.
2013, Vol. 28 
