A novel modulation control for quasi-Z-source inverters

In this paper, a single-phase quasi-Z-source (qZS) inverter (qZSI), integrating the pulse width modulation (PWM) control with interleaved placement shifted shoot-through state (STS) modulation technique, is developed to simultaneously achieve both dc voltage boost and dc-ac inversion. Instead of placing the shoot-through state in both inverter legs, the proposed method inserts the shoot-through state only in left/right inverter leg separately during the positive/negative half cycle of the output voltage to reduce switching losses and thermal stresses of the power devices. The shoot-through states shift is also studied to decrease the switching numbers of power devices and hence improve the efficiency further. The effectiveness and performance of the designed scheme and modulation strategy are proved experimentally and compared to the previous research on a built laboratory prototype.