A Novel Current Sharing Scheme for Two-Phase Interleaved LLC Converter Based on Virtual Controllable Voltage Sources

In this letter, a novel current sharing scheme for two-phase interleaved LLC converter based on virtual controllable voltage sources (VCVSs) is proposed. In each phase, the VCVS is constructed by an auxiliary winding of the other phase transformer inserted into the resonant tank. The equivalent input voltage of resonant tank, which is the composition of the equivalent ac input voltage and VCVS, can be regulated to achieve current sharing by modulating the phase-shift angle between the two phases. Meanwhile, good output current ripple cancellation effect can be naturally achieved with appropriate parameters of VCVSs. Detailed operation principle and design considerations of the proposed current sharing method are presented. Finally, a 12 V/40 A two-phase interleaved LLC prototype has been built up to verify the theoretical analysis.