Research On High Performance Low Power Level DC/DC Modular Power Supply

High-performance DC/DC module power supply is widely used in aerospace power systems,with the development of power electronic technology in recent years,the "short,small,light,thin" has become the mainstream trend of the power module design,aerospace fields of power supply module of power density,electrical isolation characteristics,stability,reliability,control accuracy and efficiency are put forward higher requirements.Based on aerospace system of small power DC/DC module power supply research,analyzes the optical coupling isolation and magnetic isolation principle and advantages and disadvantages of these two kinds of feedback circuit scheme,and puts forward a new type of magnetic isolation feedback control circuit;At the same time,in order to improve the control performance and stability of the system,aiming at considering the parasitic parameters of module power circuit topology,deduces its non-ideal models,and discuss the effects of parasitic parameters on the performance of the system;Finally,the prototype was built and the module power supply was built,and the experimental verification was carried out.First of all,the design scheme of DC/DC module power supply circuit,the technical parameters according to the analysis of several typical low power DC/DC converter topology,and put forward by secondary side synchronous rectification flyback solutions,is conducive to improve the efficiency of the module and power density.In the feedback circuit,the traditional optocoupler Current Transfer Ratio(CTR)is unstable and the working life is not long.The working reliability and stability of the module power supply are general.To improve this phenomenon,this paper adopts the temperature stability and resistance to radiation characteristics better magnetic isolation technique,put forward a kind of magnetic isolation feedback circuit,which can realize the electrical isolation and output control signal on the input and output voltage error signal tracking.The miniaturization of aerospace power supply system puts forward higher requirements for the accuracy of the converter model.Because the ideal modeling method does not consider the parasitic parameters such as transformer leakage inductance,capacitance ESR and line impedance,it is not conducive to the optimal design of the system.Is proposed in this paper a non-ideal flyback modeling method,using the state space average method analysis for CCM mode flyback small signal model,adopt the average switch network,combined with the Taylor formula for DCM flyback small signal model of mode.The results of numerical simulation and analytical modeling are compared,and the accuracy of the model is verified and the influence of parasitic parameters is analyzed.Finally,small power DC/DC module power supply for the main circuit device selection and transformer design,adopt the method of transformer winding interleaving distribution,in order to improve the power density,using planar transformer,finally,design the optical coupling isolation and magnetic isolation of two schemes of control circuit,compensation network parameters calculated,build a prototype and experiment,verify the feasibility of magnetic isolation scheme,the rationality of the converter is not ideal model and the effectiveness of feedback circuit design.