A Common Inductor Multi-Phase LLC Resonant Converter

In this paper, a new common inductor current sharing method is proposed for multi-phase LLC resonant converter for high power application. Automatic current sharing is achieved by using a common resonant inductor for all the LLC resonant stages, by connecting the resonant inductors in each phase in parallel. The proposed method can automatically share the load current without any additional circuit and control strategy. The current share performance of the proposed common inductor current share 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 (less than 0.5% current sharing error at full load) has been achieved.