A Novel Hybrid LLC Resonant Converter with Fixed-Frequency Phase-Shift Control for Wide Gain Range Applications

In this paper, we propose a novel hybrid LLC resonant converter for wide gain range applications. Its structure consists of a primary full-bridge LLC converter and an auxiliary ordinary full-bridge converter. The primary LLC unit is utilized to provide soft switching performance and the auxiliary unit extends the gain range. To facilitate the magnetic design, the converter operates with fixed frequency, and phase-shift control is applied between two units to adjust the output voltage. This converter realizes wide voltage range regulation independent of load and soft switching over an ultrawide phase-shift range. A1 kW prototype is built to verify the feasibility of this design, which exhibits a peak efficiency of 97.4%. Experimental results demonstrate good gain adjustment capability and soft switching performance.