Research Of Interleaving Double-transistor-forward Switch Power Supply Modeling And Design

Switch Power Supply is an important component of power electronics.After several decades of development,it has substituted for linear power supply to be the development tendency of the future power. Various kinds of switch power supply are applied to different power system due to the application of the new technology and the new power electronic devices,as well as the selection of the flexible topology and control scheme.Based on the practical working needs, this paper illustrates the study and designs about a kind of high-current switch power supply which can work in Vacuum environment.For the request of medium power output, high reliability, high power density, relative high efficiency, the DC-DC converter designed in this paper adopts the topology of interleaving double-transistor-forward.At first, the basic operation principle of double-transistor-forward converter is analyzed.This topology has the advantage of lower voltage and current stress,lower thermal stress, high power density and simple magnetic reset circuit compared to single-transistor-forward converter;It also has the advantage of high reliability when compared to full-bridge converter and Push-pull converter.The structure of interleaving module not only has a improvement of power density and serious forgiveness,but also has a limit of the output voltage ripple and current ripple.Then voltage control strategy and peak current control strategy is utilized respectively to built the small-signal model and design the controller.The disadvantages and advantages of each kind of strategy is compared.It found that the anti load disturbance, anti input voltage sudden increase capacity of the system utilizing the peak current mode is stronger than that utilizing single voltage control,but its multi-output cross regulation performance is not good. When the inductor current ripple is lagre, the error between the peak current and the average sampling current is hard to ignored which has the bad impact on the stability of the control system.Based on the technical index of the prototype,the parameters designing of the switch,high frequency transformer and output low-pass filter are explained in details,the drive circuit and detection circuit are introduced. Accordingly the power loss is calculated and the lager loss bringed by high-current is discussed.At last,the simulation of the converter is built with Matlab and the experiment of the prototype which can output relatively high rated power was constructed.The prototype power supply is working properly,It has good dynamic response when changing load.The results meet the requirements index.