Calculation and Analysis of Six-Phase Synchronous Motor Operating at Rated Condition by FEM

Six-phase motors are widely used in industry, for they can be useful in increasing motor capacity with limit voltage level, and be more reliable in continuous operating and be more robust in performance controlling. Up to the present, there have been many researches on six-phase motors, and they are usually analyzed by analytical methods. However, most of six-phase motors are used with variable frequency power for frequency conversion control, and the variable frequency power will produce lots of harmonics, which will make the nonlinear phenomenon of magnetic field be more complex, and produce less accuracy in analytical calculation. Therefore, it´s essential to study the performance of the six-phase motor by more efficient method. In this paper, taking the finite element method (FEM) as efficient analytical method, a six-phase non-salient synchronous motor is studied, which is supplied by a two current-source inverters and operating at rated condition. The methods for calculating the magnetic field and rated parameters for this kind of six-phase motor are provided, and the corresponding results are given. It can be observed from the torque wave that the main harmonic torques are below 5% at the rated condition, which proves that the torque ripple of the motor can be reduced efficiently by using double Y-connected windings displaced by 30 electric degrees.