Research On CLLLC Resonant Bidirectional DC/DC Converter

In the context of social progress and economic development,the power load has increased significantly,people’s demand for electricity has increased,and the requirements for power quality have also increased.Compared with AC distribution network,the DC distribution network has the advantages of low line loss,high reliability of power supply,high power quality,easy access to distributed power sources and energy storage devices,and environmental protection,which is more suitable for the demand of electric energy in today’s society.Isolated bidirectional DC/DC converter as a key device in DC distribution network has gradually received wide attention from scholars at home and abroad.In this paper,CLLLC resonant bidirectional DC/DC converter is used as the research object to study its transmission characteristics,start-up spike current suppression,efficiency enhancement method and specific parameter design.The paper firstly introduces the background and significance of isolated bidirectional DC/DC converter,and describes the research status of CLLLC resonant bidirectional DC/DC converter from five aspects,including topology,steady-state model,parameter design,soft-start strategy research and control method.Then,the working principle of CLLLC resonant bidirectional DC/DC converter is analyzed,the system voltage gain and transmission efficiency are analyzed by circuit theory,and the key parameters of the main circuit such as resonant inductance and resonant capacitor are analyzed.On this basis,a hybrid soft-start strategy is proposed to eliminate the start-up spike current,while intermittent control is used to improve the efficiency of the converter,and the resonant network and hardware and software of the converter are designed in detail.Finally,the CLLLC resonant bidirectional DC/DC simulation model is built using Matlab/Simulink simulation software.And built a converter experimental platform based on STM32C8T6.The simulation and experimental results verify the feasibility and correctness of the theoretical analysis and the design scheme,which enables the converter to keep the output voltage stable and improve the transmission efficiency under light load when the load changes.