Spectral analysis of a new six-phase pole-changing induction motor drive for electric vehicles

In this paper, a new six-phase pole-changing induction motor drive is proposed to extend the constant-power operating range for electric vehicle application. The double Fourier series is newly employed to analyze the spectra of the motor phase voltage and current. Consequently, the harmonic expression of the inverter dc-link current can be derived. In order to reduce the dc-link harmonics, a new sinusoidal pulsewidth-modulation strategy is developed for the proposed six-phase inverter. Experimental results, particularly the spectra of the phase current and the dc-link current, are given to verify the theoretical analysis.