Research On The High Power Supply Of The Two-Transistor Forward Converter

This topic mainly designed one power supply prototype used for the warehousing traction of the electric locomotive headstock, requiring when the prototype inputs 110 V dc voltage, the output dc voltage is 600 V, and the output power is 1200 W. This paper first provides an overview of various basic DC/DC topology, analyzes the advantages and disadvantages of these topologies, then chooses the appropriate main circuit topology. Due to the advantages such as the two transister forward converter with no need for additional transformer magnetic reset circuit, nonexistence of straight bridge arm danger and high reliability, it is widely applied in middle and high power convertors. Considering the factors such as power supply prototype applications and cost, this design chooses the two transister forward circuit as the main circuit topology.After the main circuit structure is determined, through the analysis and calculation for main circuit, get the parameters of the key components, then carry through components selection. Next design the control circuit and drive circuit, first of all control the chip selection, as SG3525 owns the advantages of simple structure, reliable and convenient and flexible use, thus choose SG3525 as the control chip, adopt the transformer drive to control two MOS tubes to conduct and shut off. After completing the design of electric schematic diagram, carry through the circuit component parameter calculation and selection. For ensuring the accuracy of the circuit structure and component selection, carry through the simulation of the partial and the whole circuit, after the simulation results confirm correct, carry through the practical manufacture of power supply prototype. According to the components in physical size, draw out the protel, after setting the protel in the schematic diagram, import into PCB, and carry through the layout and attachment in the schematic diagram, make PCB board, weld the components to complete the production of power supply prototype. Finally carry through the debug and test of the power supply prototype, analyze the waveform and data analysis of experiment, it can be seen that the performance of the prototype achieves the design requirements, verifying the feasibility of this kind of design scheme. As this is only an experimental prototype, many aspects need to optimize, and its stability and performance still need to improve and perfect.