Modeling And Control Of The Phase-Shift Full-Bridge Soft-Switching DC-DC Converter

With the development of science and technology,we put forward higher request to switching power supply power density,efficiency and dynamic performance.By increasing the switching frequency,we can greatly reduce the size of switching converters to improve power density,however,the switching losses increase too,electromagnetic noise increases,the soft-switching technology was presented.Switching converters can achieve zero-voltage switch or zero-current switching,significantly improve efficiency,reduce electronmagnetic interference by using soft-switching technology.Compared with other soft-switching circuit,phase-shifted full-bridge converter has a simple structure,easy to control,easy to implement,etc.It is widely used in practice.Switch converter is a typical nonlinear time-varying systems,work is relatively complicated,in order to studying the switch of the converter control problem,the first thing to establish mathematical model,and on this basis,in order to control theory was used to design the controller of the converter,so as to get better performance.This article through to the analysis of the phase-shift full bridge soft switching dc converter and design,the phase-shifted full bridge converter modeling method of soft-switching technology,and the control method is studied.First,it introduced several types of the phase-shifted full-bridge DC-DC converter using soft-switching and analysed several typical topological structures of phase-shifted full-bridge zero-voltage and zero-current DC-DC converter,summarized the characteristics of all the topologies,selected the zero-voltage and zero-current-switching full bridge converter using two diodes in series with the lagging leg for the study.Secondly,a detailed analysis has been taken on zero-voltage and zero-current-switching full bridge converter using two diodes in series with the lagging leg and showed the conditions of soft-switching to meet zero-voltage and zero-current-switching full bridge converter using two diodes in series with the lagging leg.According to the subject of performance requirements,the parameters of main circuit components was designed,on this basis,using Saber simulation software to establish themain circuit simulation model for the simulation analysis.The results show that the main circuit parameters is reasonable to meet the design requirements.Last,using state-space averaging method to establish a small-signal model of zero-voltage and zero-current-switching full bridge converter using two diodes in series with the lagging leg.This paper introduces the basic design for defects of one cycle the improved one cycle control links,applied to zero-voltage and zero-current-switching full bridge converter using two diodes in series with the lagging leg,deduced the mathematical model of the control links,system simulation is carried out by using MATLAB software,the simulation results show that the improved one cycle control can make lagging leg in series with diode of phase-shift full bridge zero-voltage and zerocurrent-switching converter can obtain good dynamic and static performance.