A dual-input full-bridge current-source isolated DC/DC converter based on Quasi-Switched-Capacitor circuit for Photovoltaic systems with energy storage

In this paper, a dual-input full-bridge current-source isolated dc/dc converter is proposed to combine the Photovoltaic (PV) system with the Energy Storage System (ESS). The proposed converter utilizes a full-bridge as the primary side, and the Quasi-Switched-Capacitor circuit as the secondary side. Compared to other multiple-input dc/dc converters with galvanic isolation function, the proposed converter utilizes less number of switches and passive components, reduces voltage stress on switches, and can achieve a high efficiency at a high switching frequency. The operation principle of the converter is presented, and a power sharing strategy between two input sources is proposed. A 2.0 kW, 1 MHz, 40 V/ 400 V prototype utilizing Gallium Nitride (GaN) switching devices is built in the lab, and experimental results show that a peak efficiency of 95.9% is achieved at 500 kHz.