| In recent years,with the increasing shortage status of global energy resources,environmental pollution and global warming,micro-grid based on distributed generation technology has been developing rapidly.Bi-directional DC/DC converter is the key converter to achieve power transmission,management,storage and grid connection.It is an important link in the construction of AC and DC hybrid micro-networks.This paper first describes the research status of Bi-directional DC/DC converter from three aspects:circuit topology,control mode and soft switching technology,then compares and analyzes the advantages and disadvantages of common design.In the second chapter,combined with the specific usage cases and requirements of the project,a complex topology was chosen.The switching mode of converter under different working modes is analyzed,and the circuit characteristics of the converter are verified by MATLAB simulation software.Meanwhile,some problems that the topology will encounter in practical application are also presented.In the third chapter,the parameters of the main components of the converter are calculated and selected,and some of the inherent shortcomings of the chosen topology are improved in structure.The fourth chapter first establishes a mall signal model of non-idea Bi-directional DC/DC converter,and designs the control system of the converter based on it.At the same time,the dynamic performance and steady state performance of the system are simulated and verified.Finally,a digital control system based on TMS320F28035 is designed,and the seamless switching technology of Buck-Boost mode is realized.Based on this,an experimental prototype is developed,and the experimental results verify the function of the prototype. |
