Soft switching bidirectional DC-DC converter with coupled inductor

Abstract

This work presents a novel soft-switching bidirectional dc-dc converter with coupled inductor. Transformer-based circuit topologies are commonly employed in conventional bidirectional converters, and soft-switching techniques, including zero-voltage switching (ZVS) or zero-current switching (ZCS), are frequently applied to mitigate switching losses. Unfortunately, the use of more than four switches and several diodes in these transformer-based schemes increase production costs and reduce conversion efficiency. In this work, a coupled-inductor bidirectional converter scheme utilizes four power switches to achieve the goal of bidirectional current control. The high step-up and step-down ratios enable a battery module current with a low voltage to be injected into a high-voltage dc bus for subsequent utilization. Experimental results based on a 800-W prototype are provided to verify the effectiveness of the proposed bidirectional converter. Since the techniques of voltage clamping, synchronous rectification and soft switching are utilized in the proposed circuit topology, and the corresponding device specifications are adequately fulfilled, the proposed converter can provide highly efficient bidirectional power conversion in a wide range on the low-voltage side.