Research On General Modeling Method Of Current Mode Control DC-DC Converter

Current-mode control is widely used in various switching converters.Compared with classical voltage-mode control,its modeling process is more complicated.On the one hand,current-mode control needs to consider the ripple of switching frequency current.On the other hand,the current-mode control is a double loop structure,which needs to introduce additional compensation links and intermediate variables.In order to simplify the modeling process of current-mode control in different topologies,some scholars have proposed a general current-mode control model,but the existing general model is difficult to achieve a good balance in the complexity,accuracy,wide applicability and physical significance of the model.This article discusses the applicable to peak current mode control and average current mode control universal modeling method,derived the general nonlinear circuit part of switch power supply,and into the current sampling,which the current control loop and power stage into a universal model,The general model can represent various DC-DC converters,Especially DC-DC converters with coupled inductors/transformers.In addition,in order to further improve the accuracy of the model,leakage sensitivity is also considered in the modeling process.The main research contents of this paper are as follows:1)A general peak current mode control modeling method is proposed.The correctness and validity of the general modeling method are verified by the modeling research of several DC-DC converter cases.At the same time,the influence of leakage sensor is considered in the modeling process,and taking TI-Boost converter as an example,the simulation comparison proves that the model accuracy can be further improved by considering leakage sensor in the modeling process.In addition,the general modeling method of peak current mode control applied to high order DC-DC converter is improved and derived.The Cuk and Sepic converters are taken as examples to verify.Finally,the correctness of the theoretical analysis is verified by simulation and experiment.The results show that the modeling accuracy of the proposed general modeling method can reach up to 1/2 switching frequency.2)A general modeling method for average current mode control is proposed.The correctness and validity of the general modeling method are verified by the modeling research of several DC-DC converter cases.The general modeling method of average current mode control for high order DC-DC converter is improved and derived.Finally,the Buck converter is taken as an example for experimental verification.The experiment shows that the modeling accuracy of this general modeling method can reach 2/5 switching frequency.3)Based on the above general modeling method,the current-mode control general modeling control is built in Simulink platform,and the application method of this modeling control is discussed through a practical case,simulation verification is carried out.The practice shows that compared with other current-mode control general model,the general model in this paper is simple to use,flexible,high modeling accuracy and wide application range,which is helpful to complete the closed-loop controller design of the target converter quickly,and has high application value in engineering.