Hybrid-Frequency Phase-Shift PWM Technique to Reduce DC-Side and AC-Side High Frequency Current Harmonics in PMSM Drives

The presence of current harmonics on both ac-side and dc-side is undesired for voltage source inverters feeding permanent magnet synchronous motor systems. This article presents a hybrid-frequency phase-shift pulse width modulation (HFPSPWM) method to mitigate the high frequency current harmonics on both sides. The mechanism of reducing the root mean square of dc-side current harmonics by phase-shift modulation is analyzed. By introducing individual switching frequency for each phase and addressing an optimization problem, the ac-side current distortion is reduced with minimal impact on the dc-side performance. Simulations and experiments validate that the proposed HFPSPWM can alleviate the total harmonic distortion of phase currents, as well as minimize the dc-side current harmonics.