LAUSR

Current-fed dual active bridge dc–dc converters are suited for renewable energy systems such as solar photovoltaic and fuel cells, due to the advantages of small input current ripple and wide input voltage range. In this article, a current-fed dual active bridge dc–dc converter based on pulse width modulation plus phase shift control is studied. The working principle and zero-voltage switching (ZVS) conditions of the converter are analyzed in depth, and it is proved mathematically for the first time that all switches can naturally achieve ZVS independently of dc inductance and leakage inductance under a wide input voltage range within full load range. Based on maximum power transfer, peak current, and root mean square (RMS) current analysis, optimal dc inductance and leakage inductance design to obtain low inductor RMS current is proposed. In addition, the detailed loss breakdown was implemented by comparing it with the nonoptimized case. The effectiveness of the theoretical analysis and design method has been verified by experimental results.