The sinusoidal pulse width modulation (SPWM) technique is used to produce the sinusoidal
waveform by filtering an output pulse waveform with varyingwidth.A better filtered sinusoidal output wavefrom can be obtained by using a high switching frequency and by varying the amplitude and frequency of a reference or modulating voltage. In SPWM technique it maintains the pulses in different widths instead of maintaining in equal widths as in multi pulse width modulation where the distortion factor (DF) and lowest orderharmonics (LOH) are significantly reduced. The figure 3.1 depicts the six step inverter composed with six switches S1 S6 with each phase connected to the middle of each inverter leg