Research On High Power Switching Converter Based On Phase-shifted Full Bridge And Synchronous Rectification

Anodic oxidation is an important process in aluminum material fabrication,in which a low-voltage high-current supply is needed.Due to the disadvantages of big volume,low efficiency and harmonic contamination,traditional SCR power supply is being replaced by high frequency switching power supply.Phase-shifted full bridge(PSFB)soft-switching technology decreased switching power loss and improved efficiency;synchronous rectification(SR)decreased the loss of rectifier and provided more efficiency improvement;the application requirement for high power supply promoted the development of parallel control technique.In this paper,a high power supply based on PSFB and SR,and its digitized parallel control system were researched and designed.First of all,this paper introduced the background and significance of the subject.The application of soft switching,SR,current sharing method were presented,and the working processes of PSFB and SR were discussed in detail.Furthermore,an optimized SR driving timing is proposed.Then on the base of these,a modular power supply and its control circuit were designed.To achieve paralleled unit high power output,a digital control system based on CAN bus was adopted.The parallel control system solved the current sharing problem,realized intelligent control and fault handling.According to the analysis and design in this paper,a 400 kW high power supply with 10 power units was produced and tested.The experimental results showed that the power supply completely meets the design target.ZVS and SR were achieved and the efficiency approached 93%.The parallel control system operated stable,which realized good current sharing and intelligent control.