Research And Design Of Low Voltage High-power Synchronous Rectification Power Supply

Low voltage and high-power switching power supply have a wide application and research in the field of industry because of its characteristics of low voltage and large current.With the demand of energy saving and environmental protection of the era,the high power switching power supply is developing to the high frequency,high efficiency,high reliability,high power density and Standardization,modularization,intelligentization and electromagnetic compatibility which is so called "four high","four modernizations".How to reduce the power loss of switching and improve the efficiency of power supply has become a hot topics in modern switching power supply.Based on the low voltage high power synchronous rectifier power supply which is the research object,this paper researched how to reduce the power loss of switching power supply,how to improve efficiency and realize digital control.Moreover,the switching power supply topology and the synchronous rectifier related technology were discussed and a full bridge full wave structure synchronous digital switching power supply is designed.A synchronous rectifier active clamp circuit model is proposed at the same time.In this paper,the hardware structure and simulation analysis of the designed power supply are carried out under the 12V/1000 A output condition.The hardware structure designed mainly from two aspects: power circuit and signal circuit.Power circuit includes the input rectifier filter circuit,the full bridge inverter circuit,the transformer,the full wave synchronous rectifier circuit and the output filter circuit.The signal circuit includes driving circuit,sampling circuit,control circuit and auxiliary power supply circui.The modules of the power supply and the small signal model of the main circuit is built in MATLAB as well as the closed loop controller is designed.The open loop and closed loop simulation of the power supply system is carried out,and the rationality of the design is verified by simulation analysis.Finally,the preliminary test platform is preliminarily debugged,and the rationality of the waveform of the auxiliary power supply and the driving signal is analyzed.