A Hybrid PWM Technique Employing Variable Switching Sequences for Current Ripple Suppression in Dual Three-Phase PMSMs

Dual three-phase electrical machines inherently have lower 6<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> ± 1 order harmonic impedance than conventional three-phase machines, particularly in their sensitivity to voltage pulses from a drive in terms of current harmonics. Based on space vector pulse width modulation (SVPWM) methods, this article introduces a systematic approach to numerate all the feasible switching sequences and examine their current harmonic performance. Five distinct switching sequences, along with their optimal operational regions determined by modulation vector position, are proposed, considering variations in the machine parameters. A straightforward PWM generation method, incorporating dead-time compensation, is also considered. The theoretical evaluation has been validated with both piecewise linear electrical circuit simulation (PLECS) simulation results and experimental evaluation conducted on a 270 kW hardware prototype.