A Hybrid Full-Bridge Converter with Wide Output Voltage for High-Power Applications

A hybrid full-bridge converter that consists of a secondary-side phase-shift full-bridge converter (SPS-FBC) and a full-bridge LLC converter is proposed in this study. The wide zero-voltage switching (ZVS) range of the primary switches can be achieved and the series inductor of the SPS-FBC converter does not need to be specially designed to help achieving the soft switching operation with a set of shared high frequency inverter circuits. The dual outputs of the proposed hybrid converter are connected in series, reducing the voltage stress of the power device in the secondary side. The whole dc-output voltage can be regulated by primary-side phase-shift and secondary-side phase-shift dual-mode control scheme within the desired voltage range, by which the two output voltages are regulated independently and free from cross-regulation. Therefore, the proposed converter is suitable for high voltage, high power and wide output voltage range applications. The working principle and steady-state characteristics of the proposed converter are presented and verified in experiment of a 3 kW prototype. The experimental results show that the proposed converter maintains high efficiency throughout the voltage range, and the peak efficiency is 97.43%.