Improved inverter utilisation using third harmonic injection

In this paper, a comparative analysis of the carrier based pulse width with modified zero space vector modulation or third harmonics injection used in the inverter control is presented. The placement of zero space vector components with in the carrier interval determines the harmonic performance of the modulation strategy. The space vector pulse width modulated inverter gives 15 percent more line to line voltage as compared with the conventional sine pulse width modulated (SPWM) inverter. The optimized zero vector injection controls the blanking time and minimum pulse width of an operating inverter switch. The simulation results are presented for the three phase voltage source inverter to ascertain the effect of this technique. It is also tested on the laboratory prototype inverter to confirm the effectiveness of this modified SVPWM technique.