Phase-shifted full-bridge converter with coupled-inductor-based rectifier

In this paper, a phase-shifted full-bridge (PSFB) converter with a coupled-inductor-based rectifier is presented. The proposed PSFB converter alleviates the circulating-current problem of conventional PSFB converters. As a result, it can operate with a larger effective duty-cycle over a wide range of input voltage or output load conditions. The transformer turn-ratio can be better designed in terms of the primary-side conduction loss and the secondary-rectifier voltage stress. Due to the reduced secondary voltage stress, diodes with a lower forward-voltage drop can be used in the rectifier of the proposed converter, which results in s reduction of the secondary-side conduction and snubber losses. With these advantages, the proposed converter can achieve a higher power-conversion efficiency when compared to conventional converters. To verify the effectiveness of the proposed converter, this paper presents the operating principle, dc analysis, and experimental results of a prototype converter built with the specification of a 1.0 kW, 300–400 V input, a 50 V output, and a 100 kHz switching frequency.