A New Full-Bridge Converter with Phase-Shifted Coupled Inductor Rectifier

Abstract

A conventional phase-shifted full-bridge (PSFB) converter is one of the most promising topologies in high power/high efficiency applications because of its small RMS current, inherent zero-voltage switching (ZVS) capability, and clamped voltage stress of the primary switches. However, when it is designed to satisfy a hold-up time requirement, it operates with small effective duty-ratio in nominal state which causes a large RMS current in the primary side. To solve these problems, secondary-side phase-shifted controlled full-bridge converter with a new coupled inductor rectifier is proposed in this paper. In the nominal state, the proposed rectifier uses synchronous rectification to reduce the conduction loss in the rectifier. And, by shifting the phase of rectifier switches, the proposed converter obtains additional voltage gain during the hold-up state. As a result, the proposed converter can be designed regardless of the hold-up time which results in high efficiency in entire load condition. The effectiveness and feasibility of the proposed converter is verified with 320–400 V input and 56 V/12.8 A output prototype converters.