A Flyback-Integrated Phase-Shift Full-Bridge Converter for High Efficiency

초록

This article proposes a new flyback-integrated phase-shift full-bridge (PSFB) converter to improve the overall efficiency of the conventional PSFB converters for applications requiring low output voltages and high output currents. It is implemented by replacing the output inductor with a coupled inductor and connecting its secondary side to the output in a flyback configuration. During the freewheeling period, the proposed converter transfers the energy stored in the coupled inductor to the output via the flyback circuit, consisting of only one coupled inductor winding and a low-voltage-rated diode. This provides the following main advantages: 1) elimination of the circulating current; 2) a lower forward voltage drop on the freewheeling diode; and 3) a reduced number of conducting components. Consequently, power losses on both the primary and secondary sides are significantly reduced. To validate the effectiveness of the proposed converter, a 300 W prototype was designed and tested. Experimental results confirmed an improvement in overall efficiency compared with the conventional converters, achieving 0.8% and 2.2% higher efficiency than the center-tapped rectifier and coupled inductor rectifier, respectively, under full-load conditions.

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