Forming of Six-Phase Double Layer Induction Motor Windings

coil winding is smaller than six-phase motor withconcentrated double layer full pitch coil winding.Analysis of the considered first type of winding indicates,that during one pole pitch the relative magnetomotive forceF1(φ) has the shape, shown in “Fig. 7”. Analysis of thesecond type winding shows, that relative magnetomotiveforce F2(φ) in the one pole pitch displacement varies in theway, shown in “Fig. 8”.Fig. 7. Relative magnetomotive force F1(φ) ant its approximation by Fourierseries F1,Σ50(φ).the first harmonic of the first winding approximately is equalto 0.8 and that of the second winding is equal to 0.6. So fromthe view of first harmonic the motor with concentrated doublelayer short pitch coil winding will have higher efficiently thanmotor with concentrated double layer full pitch coil winding.Analysis shows, that even harmonics have the sameamplitude and they are equal to zero. Research indicates thatthe odd higher harmonics of concentrated double layer fullpitch coil winding having greater amplitude than concentrateddouble layer short pitch coil winding. While the higherharmonics increase torque oscillations and heat loss, it ispossible to state, that the first winding has greater efficiency.So research indicated that according to the harmonicspectrum, the concentrated double layer short pitch coilwinding has greater efficiency than concentrated double layerfull pitch coil winding.III. CONCLUSIONSThe advantages of multiphase motors against three phasemotors are discussed. The areas of application of themultiphase motors are considered.Two types of six-phase motor windings connections areanalysed: concentrated double layer short pitch coil windingand concentrated double layer full pitch coil winding.Concentrated double layer short pith coil six phase windinghas the first harmonic greater by 22 % than concentrateddouble layer full pith coil six phase winding.Research indicated that according to the harmonicspectrum, the short pith coil winding has greater efficiencythan full pith coil.REFERENCESFig. 8. Relative magnetomotive force F2(φ) ant its approximation by Fourierseries F2,Σ50(φ).Space harmonic spectrum of each winding magnetomotiveforce was obtained on the base of Fourier series. Analysis ofmagnetomotive forces gives information about higherharmonics that appear in the air gap. More detailedcalculation shows that concentrated double layer short pitchcoil six-phase winding has the first harmonic significantlygreater (22 %) than concentrated double layer full pitch coilsix-phase winding. Analysis shows, that relative amplitude of[1] E. Levi, “Multiphase electric machines for variable-speed applications,”IEEE Trans. Industrial Electronics, vol. 55(5), pp. 1893-1909, May2008.[2] R. Gregor, F. Barrero, M. J. Duran, M. R. Arahal, S. Toral, “Modelbased predictive current control of an asynchronous six-phase motordrive,” available from Internet: .[3] J. I. Leon, O. Lopez, L. G. Franquelo Fellow, J. Doval-Gandoy, S.Vazquez, J. Alvarez, F. D. Freijedo, “Multilevel multiphasefreedforward space-vector modulation technique,” IEEE Trans.Industrial Electronics, vol. 57(6), pp. 2066-2075, 2010.[4] E. Levi, “Multiphase electric machines for variable-speed applications,”IEEE Trans. Industrial Electronics, vol. 55(5), pp. 1893-1909, May2008.[5] O. Lopez, J. Alvarez, J. Doval-Gandoy, F. D. Freijedo, “Multilevelmultiphase space vector PWM algorithm,” IEEE Trans. IndustrialElectronics, vol. 55(5), pp. 1933-1942, May 2008.[6] R. Gregor, F. Barrero, S. Toral, M. J. Duran, “Realization of anasynchronous six-phase induction motor drive test-rig,” in Proc.International Conf. Renewable Energy and Power Quality, 2008.[7] R. S. Miranda, C. B. Jacobina, A. M. N. Lima, “Modeling and analysisof six-phase induction machine under fault condition,” IEEE Trans.Power Electronics, vol. 9(1), pp. 824-829, 2009.[8] I. Rata, P. Todos, I. Nuca, “A review of multiphase electric machines,”Electromechanical and Power Systems, vol. 6(1), pp. 154-159, 2007.96