Research On Current Sharing Characteristics Of Interleaved LLC Resonant Converter Based On Fully Coupled Inductor

LLC resonant converter has the advantages of wide input voltage range,large power density,soft switching characteristics and so on,so it is widely studied and applied.With the improvement of application power,the multi-phase LLC resonant converter is often operated in parallel.However,due to the limitations of the current manufacturing process,the resonance parameters of each phase resonant cavity are not completely consistent,which results in the phenomenon of uneven current of the multi-phase LLC resonant converter.To solve the above problems,this paper proposes a current sharing strategy of interleaved parallel LLC resonant converter based on full coupled inductors.firstly,the development of resonant converter is described,different resonant converters are introduced,and their characteristics are analyzed in detail.This paper introduces the current sharing technology of LLC resonant converter at home and abroad in recent years,and expounds its characteristics and limitations.Then,the working principle of the single full bridge LLC resonant converter is analyzed,the fundamental equivalent model of the resonant circuit is established,and the basic characteristics of the converter are studied.On this basis,the working modes corresponding to each time sequence of the interleaved LLC resonant converter are analyzed,and the fundamental equivalent model of the resonant circuit of the interleaved LLC resonant converter is established,the parameters of the cavity are derived.Then,the current sharing characteristics of the converter are analyzed under the condition of the parameter error of the resonant cavity.Furthermore,the current sharing strategy of series coupled inductors in each resonant slot of interleaved LLC resonant converter is proposed.The fundamental equivalent model of resonant circuit based on coupling inductor is established.The influence of coupling degree of coupling inductor on voltage gain of converter is analyzed.The relationship between inductance and current sharing effect of coupling inductor is analyzed.The design method of coupling inductor is given.Finally,according to the design parameters of the converter and the selected components,a test prototype is built.The correctness of the theoretical derivation and the effectiveness of the current sharing scheme are verified by simulation and experiment.There are 55 figures,6 tables and 52 references in this paper.