A Variable-Frequency and Phase-Shifted Based Current Sharing Control for Parallel LLC Resonant Converters with Parameter Differences

In order to achieve the power balance of each module in a parallel converter system, a variable-frequency (VF) and phase-shifted (PS) based current sharing control for parallel LLC resonant converters with parameter differences is proposed in this paper. Once the resonant frequency is reached, the modules will switch to the PS mode, achieving current-sharing over a wider range of voltage gain while the secondary-side diodes will be turned off for zero-current switching (ZCS). The effectiveness of proposed method is finally verified on a prototype two-phase input-parallel output-parallel (IPOP) LLC resonant converters.