Magnetic Circuit Calculation of Fifteen-phase Induction Motor With Non-sinusoidal Supply

In view that the stator and rotor resultant magneto-motive forces (MMF) of the fifteen-phase induction motor under non-sinusoidal supply is of non-sinusoidal distribution, the distributed magnetic circuit method is put forward to perform magnetic circuit calculation and the magnetizing reactances are deduced. Based on fundamental and 3-order harmonic resultant MMF, the presented method is utilized to divide the half-pole motor model into equi-interval sections with circumferential air-gap node flux densities obtained by iteration and Fourier series decomposed into fundamental and third harmonic ones. The equivalent circuit is combined with the distributed magnetic circuit method to finally determine the fundamental reactance and 3-order harmonic reactance by iterative method under given voltages. To carry out no-load experiments for a sampled fifteen-phase induction motor, the measured fundamental reactances and third harmonic reactances are gained and compared with the calculated ones. The good agreement between calculated reactances and measured ones shows the validity and accuracy of the presented method.