Generalized Space Vector Modulation for Ripple Current Reduction in Quasi-Z-Source Inverters

This article proposes a generalized space vector modulation (SVM) strategy for the three-phase quasi-Z-source inverter (qZSI), which can reduce the inductor current ripples by limiting the peaks in different sectors of the vector space. In the conventional ZSVM6 strategy, the shoot-through interval is divided into six equal parts, which is easy to implement. However, the inductor current ripples are not optimized. Generally, larger inductance is required to limit the current ripples, resulting in poor power density. By contrast, the proposed SVM strategy can minimize the current ripple, while maintaining the same total shoot-through time. Although the shoot-through intervals in the proposed SVM strategy are not identical, easy implementation still holds. The generalized strategy can ensure that the inductor current ripples are always smaller than the peak of the inductor discharging current ripple in a switching cycle. The proposed SVM strategy is derived in details and compared with the conventional ZSVM6 strategy. Simulations and experimental tests are presented to verify the effectiveness of the proposed modulation strategy for the inductor ripple current reduction.