A PWM Scheme for a Five-Phase VSI Supplying a Five-Phase Two-Motor Drive

Application of power electronics in electric drives enables utilisation of AC machines with a phase number higher than three. Such multi-phase motor drives are nowadays considered for various applications. Multi-phase drives are invariably supplied from multi-phase voltage source inverters (VSIs) and adequate methods for VSI pulse width modulation (PWM) are therefore required. This paper deals with carrier-based PWM, where offset injection enables an improvement in the DC bus utilisation without moving into the over-modulation region, while still providing sinusoidal output phase voltages. An appropriate carrier-based PWM scheme with offset injection is developed for a five-phase VSI supplying two series-connected five-phase machines. The simulation results shown in the paper prove the viability the proposed PWM scheme. Experimental results, illustrating application of the carrier-based PWM in series-connected five-phase two-motor drives, are also included