Research On Modeling And Simulation Of High Reliable DC-DC Converter

With the increasing of power level and switching frequency of the switching power supply,the reliability requirements are getting stricter.Simulation is an important part between the parameter design and the actual prototype.The inaccuracy of the simulation model will bring a series of problems,such as long experimental debugging time,repeated data test,and increaseing budget caused by device adjustment.Therefore,it is necessary to improve the reliability of the simulation and achieve a highly reliable pre-assessment.In this dissertation,Buck converter is taken as the research objective,and the phenomenon of the converter characteristics caused by device parasitic parameters,PCB trace parasitics and uncontrollable factors(such as process level,temperature and voltage)is studied.The actual simulation model is established for the main components of the Buck converter.The simulation and modeling of the Buck converter considering the actual parameters of the device are carried out,which avoids the influence of the device parameter characteristics on the performance of the converter during the experiment,and provides the reference of device selection.On the basis of the Buck converter simulation circuit including actual model of devices,the parasitic parameters of the PCB trace are extracted,and the parasitic parameters of main circuit and control loop are superimposed and simulated,so as to obtain the related law of the influence of PCB trace parasitics on the Buck converter.The proposed block modeling analysis method is convenient to locate the main PCB trace parasitic parameters that affect the stability of the converter.It can solve the range of parasitic parameters and provide reference for PCB design.Aiming at the Buck converter with precise consideration of parasitic parameters,a Buck converter modeling method are proposed in this dissertation based on equivalent circuit modeling method and energy conservation modeling method.Based on this,the large signal model,DC model and small signal model of the Buck converter are derived.The effectiveness of the modeling method is verified by simulation.Finally,the Monte Carlo method is used for sensitivity analysis.The influence of component parameter drifting on the output characteristics and loop stability of the Buck converter is studied and a related law is obtained.The correctness of theoretical analysis and the feasibility of en gineering practice are verified by simulation and experiment.The final experimental results are very close to the simulation results,which solves the problem that there is a big gap between the simulation results and the experiment results of DC-DC converter in engineering.