Full-bridge LLC Resonant High-voltage DC-DC Converter with Hybrid Symmetrical Voltage Multiplier

This article presents an LLC resonant high-voltage DC-DC converter based on the hybrid symmetrical voltage multiplier that consists of the full-bridge inverter circuit, one resonant tank circuit, one power transformer, and the voltage multiplier circuit. The proposed converter operates below resonance on the negative slope region of DC characteristics curve for realization of zero voltage switching (ZVS) operation. Within this operating region, the power switches and output diodes of the converters generally operate under the ZVS and zero current switching (ZCS) conditions, respectively. The detail structure, design procedure, operation, and steady-state analysis of the proposed converter are thus described. Furthermore, an experimental prototype was built and tested with the input voltage of 100VDC. The results show that the proposed converter is capable to operate under soft-switching conditions, resulting in higher efficiency. The maximum efficiency of the proposed converter of about 96% was recorded at the output power of 550 W.