Study On Reactance Parameter And Motor Design Of Multiphase Permanent Magnet Motor

Compared with three-phase permanent magnet synchronous motor(PMSM), six-phase PMSM possesses of high frequency of space harmonic,high-capacity with low-voltage,high-usage of slot , and so on, except high-efficiency, high power density and high energy saving, so it is applicable for very widespread field. Parameter of PMSM is very important .Calculation and test are always emphasis and difficulty of research on PMSM. Because stator winding phases of six-phase PMSM is increased, self-inductance and mutual-inductance of winding are more complex. Parameter calculation and test are more difficult. The paper is devoted to study on parameter calculation and test of six-phase PMSM and motor design .Three parts is included as follows:First, with dq transformation from stator inductance matrix at stationary coordinate system of six-phase to diagonal and constant matrix at rotary coordinate system of two phases, expression of direct-axis and quadrature-axis synchronous inductance is made, and the relation of nonlinear is eliminated. A conclusion is made that direct-axis and quadrature-axis synchronous inductance of six-phase PMSM is double direct-axis and quadrature-axis synchronous inductance of any Y winding.Secondly, on the basis of the calculation of permanent magnet synchronous motor, six-phase PMSM can be resolved into direct-axis state and quadrature-axis state, and direct-axis and quadrature-axis synchronous reactance is calculated in these two states with finite element method. Then the relation between synchronous reactances and parameters of motor dimension are analysed.Thirdly, on the basic of voltage-ampere method which tests the reactance of three -phase PMSM, the voltage-current method is improved to suit for the reactance test of six-phase PMSM. Then calculation and test result are compared.Finally, a low speed six-phase PMSM and rated power 75kW has been developed. Through finite element method and Fourier analysis, pole-slot ratio,air gap length,permanent-magnet dimensions,no-load leakage factor, and so on are determined. And mechanical intensity of stator and rotor are calculated. Reactance parameter is used in electromagnetism calculation program, and design value is made. Design value andexperimental measure results are basic agreement.