Research On Current Sharing And Control Technology Of Interleaved Bidirectional LLC Resonant Converter

Thesis,the magnetic integrated structure is used to replace the traditional current loop to achieve the output current balance.The small signal model of the converter is established,and the transfer function is obtained to compensate the voltage loop and realize the traditional double closed-loop function.Firstly,the working principle and mode of the bidirectional LLC resonant converter are analyzed.The AC equivalent circuit of the bidirectional LLC resonant converter is established by using the fundamental approximation analysis method.The expression of voltage gain is obtained,and the influence of parameters on the converter is analyzed,which provides a theoretical basis for the analysis of the following chapters.Secondly,in order to meet the need of high power converter,the interleaving parallel technology is introduced to realize the expansion,and the voltage gain of the converter is analyzed when the parameters of the resonant elements change,and the influence of the parameters change on the two-phase current sharing is further analyzed.The output current of the two LLC converters is equalized by using the driving phase interleaving 180 degrees control and the magnetic integration of the external inductance.The AC equivalent circuit of vertical magnetic integrated converter obtains its voltage gain,verifies the feasibility of the current sharing scheme of magnetic integrated converter,obtains more accurate coupling coefficient by simulation method,and then completes the design process of coupling inductance.Secondly,the equivalent circuit model method is used to establish the small signal model of the magnetic integrated converter,and the transfer function of the output voltage to the switching frequency is obtained.The compensation link of the converter is analyzed and designed,and the traditional PI control is adopted.Finally,saber simulation is used to verify the feasibility,and then an experimental platform is built to verify the correctness of current sharing scheme and voltage closed-loop theory.There are 57 papers,1 tables and 63 references.