MODELING a transistor converter-fed permanent magnet poly-phase machine and a variable-frequency drive controller under non-sinusoidal back-EMF conditions

The paper presents a model of a poly-phase permanent magnet motor of the marine propulsion drive energized by multistage VSI. The model defines more precisely the non-sinusoidal waveform of back-EMF and its impact on the current distortion and electromagnetic torque ripples. The paper concludes by analyzing simulation results that have shown significant suppression of high order current harmonics and corresponding decrease in torque ripples due to the proposed control algorithm realized in a phase reference frame.