| The isolated bidirectional full-bridge DC-DC converter has the advantages of power conversion and electrical isolation,and has been widely used in the fields of electric vehicle charging and discharging systems,micro-grid,and new energy power generation systems.However,the dual phase-shifted converter has a negative input power in one switching cycle,which means that there is a phenomenon of backflow power.The backflow power will increase the current stress of the converter and increase the switching loss,which will eventually cause the converter efficiency to decrease.Therefore,it is of great value and significance to study the converter from the perspective of reducing the return power.This paper first establishes the mathematical model of the transmission power of the dual-phase-controlled isolated bidirectional full-bridge DC-DC converter,and analyzes the mechanism of the backflow power generation and the conditions for the realization of soft switching;Secondly,the problem of excessive backflow power under soft switching conditions of the converter,an optimal control method of backflow power is designed.In this method,the converter can achieve both soft switching and zero backflow power as a constraint.Combined with the mathematical model of the transmission power,the modeling and power partitioning of the minimum backflow power under soft switching conditions are carried out,and each optimal control of the power zone;Finally,a simulation model is built,the results are verified by simulation.Finally,this paper designs and builds an experimental prototype with TMS320F28377D control chip as the control core,and gives the relevant circuit parameters of the converter main circuit,drive circuit and so on.In addition,the open loop verification of the converter is carried out.The experimental results show that the converter can realize soft switching,And its backflow power decreases as the internal shift increases. |
PDF Full Text Request