Soft-switching Bi-directional High Step-up/down Converter for Battery Charging Applications

A bi-directional high step-up/down converter for battery charging applications is proposed in this paper. Energy is transferred in between low- and extreme-low voltage buses in this isolated DC-DC converter using a minimum number of switches. Energy trapped in the leakage inductance of the high-frequency transformer (HFT) is recycled to achieve the soft switching when transferring energy into both directions. The operation of the proposed converter is validated and verified using the simulation and experimental results.