Hybrid Modulation of Parallel-Series $LLC$ Resonant Converter and Phase Shift Full-Bridge Converter for a Dual-Output DC–DC Converter

A novel pulse frequency and phase shift hybrid modulated dual-output dc-dc converter is proposed in this paper. The proposed converter is composed of hybrid modulation of an input-parallel-output-series LLC resonant converter and a phase shift full bridge (PSFB) converter. The output voltage of the LLC resonant converter is modulated by the switching frequency, whereas the output voltage of the PSFB converter is modulated by the phase angle; therefore, the two output voltages are regulated independently and free from cross regulation. The series inductor of the PSFB converter does not need to be specially designed to help achieving the soft switching operation, and the duty cycle loss could be mitigated. Zero-voltage switching can be achieved on the power switches in the whole load range. Finally, a 1.2-kW 400-input 200-400-V and 48-V output prototype is built and tested to verify the effectiveness of the proposed converter.