A Common-Inductor Passive Current Sharing Method for Multiphase CLLC Converter

In recent years, with the rapid development of electric vehicles (EV), there has been a growing demand for high-power, bidirectional EV charger. The CLLC resonant converter is a good topology candidate for EV charger due to its zero-voltage switching (ZVS) and zero-current switching (ZCS) characteristics. But the input-parallel-output-parallel multiphase CLLC converter suffers phase currents unbalance, due to the resonant parameter errors caused by component production tolerances. This paper proposes a novel common-inductor passive current sharing method for multiphase CLLC converter, which achieves excellent current balancing without the need for additional components or control. By establishing an equivalent circuit based on the FHA, the current sharing error evaluation for load current is introduced to assess the current balancing performance. The current balancing performance of the proposed common-inductor multiphase CLLC resonant converter is compared with the common-capacitor multiphase CLLC resonant converter.