A Single-Phase Quasi Z-Source AC-AC Converter with a Series Connection of the Output Terminals

In this study, a single-phase quasi Z-source AC-AC converters with a series connection of the output terminals is proposed. The proposed system has configuration that the input terminals of two quasi Z-source AC-AC converters are connected in parallel and its output terminals are connected in series. The out of phase mode and in phase mode of the proposed system are presented. To verify the validity of the proposed converter, a DSP controlled hardware was made and PSIM simulation was executed. As a result, controlling the duty ratio of the converter, the desired buck-boost output voltages could be generated. For each modes, as compared with the single converter operation, the proposed converter could enhance the efficiency and input power factor according to different loads. Also, in case of the out of phase mode under the constant load, the efficiency and input power factor of the proposed system are increased 10[%], 35[%] respectively in compared with the single converter. And, the output voltage is constantly controlled in dynamic state in case while the load is suddenly changed.