A Design Of Electroplating Power Supply Based On Phase-Shifted Full-Bridge

With the rapid development of science and technology,the electroplating industry has developed rapidly.The high efficiency,high reliability and control method of low-voltage high-current high-frequency electroplating power supplies have become the current research hotspot.With the development of high frequency,the power density and integration of electroplating power supplies are higher,but the switching losses and electromagnetic interference of switching devices increase.At high frequencies,phase-shifted full-bridge soft-switching technology which has obvious advantages over the traditional hard-switching technology can effectively reduce switching losses and electromagnetic interference.In addition,in the case of lowvoltage and high-current output,the conduction loss of rectifier tube is very large,which limits the improvement of power efficiency.Synchronous rectification technology can solve this problem better.In this paper,ZVS phase-shifted full-bridge converter is studied as the main circuit of electroplating power supplies,Based on this,A low-voltage and high-current electroplating power supplies with maximum output power of 1.2 kW is designed.Firstly,in order to meet the design requirements of high power density,low cost and high efficiency,the ZVS phase-shifted full-bridge converter topology is adopted in this paper,and the working principle,soft switching conditions and duty cycle loss of the converter are analyzed in detail,and the influences of various parameters on the converter characteristics are given.Secondly,for the voltage oscillation of the rectifier side rectifier,this paper uses the clamp diodes which are on the primary side of the converter to suppress the voltage oscillation of the rectifier.Thirdly,in view of the problem of transformer magnetic saturation,the method Connectting interval capacitor with the transformer can prevent the transformer from saturation.Fourthiy,in order to reduce the conduction loss of the output rectifier,the synchronous rectification technology is adopted,and a synchronous rectifier circuit based on the original control signal is designed.Fifthly,in order to reduce the cost,a phase-shifting resonant controller UC3875 is used to realize closed-loop control and over-current overtemperature protection of power supply,and the displays of current voltage and the setting of output voltage and current are realized by the PIC18F45K80 single chip microcomputer.Finally,the rationality and feasibility of theoretical analysis are verified by simulation model in this paper,Then,An experimental prototype is built to verify the correctness of design scheme.The full-bridge switch tube of the prototype realizes soft switching,and the secondary side of the converter realizes synchronous rectification at 70 kHz working frequency,and the efficiency of the whole power supply has been greatly improved compared with the original power supply.