A high set-up quasi-Z-source inverter based on voltage-lifting unit

Compared to Z-source inverter, the switched-inductor quasi-Z-source inverter (SL-qZSI) provides a higher dc-link voltage while remaining the continuous input current and a common ground with the dc source. In some new energy power generation systems, the input voltage is environmental affected and sometimes is too low, thus the boost ability of SL-qZSI may be still not enough. By just replace one of the diodes in switched-inductor unit with a capacitor, a voltage-lifting unit is established. This paper deals with a high set-up quasi-Z-source inverter based on voltage-lifting unit (VL-qZSI). The proposed VL-qZSI has an improved boost factor while keeping the advantage of SL-qZSI. For the same input and output voltage, VL-qZSI can greatly reduce the shoot-through time, so the conduction loss in shoot-through state can be decreased, and the efficiency can be improved. This paper presents the operating principle and the analysis on VL-qZSI and compares it with qZSI and SL-qZSI. A prototype is established in the lab, the experiment results verified the correctness of the analysis.