Coupled Inductor-Based Wide Gain Four-Switch DAB DC–DC Converter

A coupled inductor-based wide gain four-switch dual active bridge (DAB) dc-dc converter is proposed in this article. The converter is obtained by linking the inductors of two buck-boost by means of a parallel transformer (with leakage inductor). The converter integrates four magnetic components, including two dc inductors, one transformer, and one leakage inductor into one coupled inductor to reduce the number of magnetic components. Full-load range zero voltage switching (ZVS) of all switches is achieved using pulsewidth modulation (PWM) plus phase shift (PPS) control. Voltage matching control is used for the primary and secondary bridge arms to meet the voltage matching across the equivalent leakage inductor. The operating principle of the converter and the ZVS conditions are thoroughly analyzed, and the full-load range ZVS is achieved for all switches by rationally designing the two dc inductor parameters taking into account the switching junction capacitance. In addition, the magnetic integration and parametric design are analyzed in detail. Finally, an 800-W prototype is built, and the experimental results verify the validity of the theoretical analyses and design methods.