An Input-Current-Ripple-Free High-Voltage-Gain Quasi-Z-Source DC–DC Converter With Soft-Switching Technology

An input-current-ripple-free high-voltage-gain quasi-Z-source dc–dc converter with soft-switching technology is introduced in this article. It achieves zero input current ripple (ZICR) by introducing a parallel branch of an extra inductor, a coupled winding, and a capacitor at the input port. The voltage of the added inductor is opposite to that of the coupled winding. Meanwhile, all the switches in the converter achieve zero-voltage switching, and all the diodes achieve zero-current switching, which can decrease the switching losses of the switches and the reverse recovery losses of the diodes. The added coupled winding is of a smaller inductance value so that a smaller copper loss and volume are introduced, thereby maintaining the efficiency and power density of the converter. To validate the proposal, a 100-kHz 200-W 38–380-V experimental prototype is built. The efficiencies of the proposed converter with ZICR and without ZICR are 95.1% and 95.8% at the rated power, respectively. The experimental results prove the effectiveness of the theoretical research, indicating the feasibility of the presented converter.