Control And Design Of Parallel Current Sharing System For Multiple Power Modules

The application of distributed power system is more and more widely because of the need of high power load.Parallel power supply of multiple power modules is more commonly used.However,because the external characteristics of each power module are not completely consistent,it is necessary to introduce current sharing control to balance power distribution in parallel system of power modules.Current sharing technology has become one of the key technologies of power module parallel connection.Through small signal analysis of DC/DC converter,this paper expounds the necessity of parallel current sharing technology,and makes a detailed analysis of the principle and characteristics of current sharing technology,compares the advantages and disadvantages of several current sharing methods commonly used at present.Among many current sharing methods,The maximum current automatic current sharing method is widely used because of its high precision and redundancy.In this paper,Buck topology is used as the main power circuit structure of power module.The working principle of buck circuit is analyzed,the main circuit parameters are designed,and the control circuit of power module is designed with TL494 control chip.In addition,the detailed design schemes of driving circuit,auxiliary power supply circuit and protection circuit are given to complete the power module.Above,complete the schematic design of the main circuit of the power modu]e.In the aspect of current sharing control,this paper analyses the load current sharing mode and structure of the maximum current automatic current sharing method in detail.The current sharing control circuit is designed with the current sharing control chip UCC39002,and the parameters of the current sharing control circuit are calculated.According to the characteristics of maximum current automatic current sharing method,a three-loop control circuit is designed by using voltage loop,current loop and current sharing loop.According to the design of the main circuit and current sharing control circuit of power supply,the prototype of power supply module is made,the experimental platform is built,the prototype test of a single power supply module and the parallel operation of two power supply modules are realized,and the current sharing effect of the parallel operation of two power supply modules is analyzed and compared.The experimental results show that the current sharing method is more effective and achieves the design target.