A common capacitor multi-phase LLC resonant converter
In this paper, a new common capacitor current sharing method is proposed for multi-phase LLC resonant converter. Automatic current sharing is achieved by using a common resonant capacitor for all the LLC resonant stages, by connecting the resonant capacitors in each phase in parallel. The proposed method can automatically share the load current without any additional circuits and control strategy. The current sharing performance of the proposed common capacitor current sharing method is analyzed under Fundamental Harmonic Analysis (FHA) assumption. A 600W two-phase LLC converter prototype based on the proposed method is built to verify the feasibility. Excellent current sharing performance (6.5% current sharing error at a wide load range) has been achieved.