A Common-Ground Quazi-Z-Source Single-Phase Inverter Suitable for Photovoltaic Applications

In this article, a coupled inductor common-ground single-phase inverter, well-suited for photovoltaic (PV) applications, is presented. The proposed PV inverter is constructed based on a two-stage topology. At the first stage, a high gain DC-DC structure converts low PV voltage to the high bipolar output voltages. The produced bipolar output voltages are the inputs for the conventional half-bridge inverter in the second stage. It is noteworthy that the parasitic capacitors between the PV panel and its ground provide the path for circulating the leakage current in conventional configurations. This problem is tackled in the proposed topology by making a common-ground structure. Furthermore, the first stage contains only one switch with low voltage stress, which leads to a significant suppression in conduction losses. The proposed DC-AC structure has the ability to reduce the input current ripple and also recycle the leakage energy caused by the coupled inductor. The operation principles of the proposed structure are analyzed in detail, and finally, the experimental results are accomplished to confirm the accuracy of the performed analysis.