Comparison of different PWM schemes for n-phase VSI

This paper presents the development of three different generalized PWM schemes for a n-phase voltage source inverter (VSI) in matlab/simulink. Multiphase (n-phase) voltage source inverters are dominantly used to supply the multi-phase drives which are used for high power applications. It is necessary to develop suitable switching schemes for the inverters to provide required output voltages to a multiphase machine.The schemes namely SPWM, PWM technique with m^th harmonic injection and offset injection are discussed. The performances of the inverter with 5, 7 and 9 phases are analyzed with these switching techniques. The output voltage, THD and current ripple are observed through simulation. The effectiveness of the schemes is compared for different modulation indices and the results are presented.