Thermal Design For A Kind Of Dc/dc Converter With High Power Density

Switching power is the power source of all electronic devices.Power Module is a kind of switching power.It has the characteristics of small volume and high efficiency.It has been widely applied to signal access equipment,transformation equipment,communication equipment,automobile,aviation and other fields.The module power Studied in this paper is mainly used in communication.With the development of 4G/5G technology,mobile communication devices(such as smart mobile phone)has been widely used,the requirements for power module is more and more rigor.They hope the power module volume become smaller and smaller,so the power density of power module will be more and more high,the heat generated will be more and more.It is well knew that the heat is an important factor affecting the reliability of the power module.This paper mainly studies the thermal design of a kind of power module with high power density.Firstly.Solving the heat source of the module and reducing the heat of the module.To solve the heat source,the main method is to improve power module efficiency and reduce power loss.In this paper,several common topology of power supply are compared and analyzed.Based on the characteristics of the module power supply,a hard-switching full-bridge circuit topology is adopted.Combined with synchronous rectification technology,parallel current sharing technology and planar transformer application,the efficiency of the entire module is up to 96%,greatly reducing the module power loss.Secondly,solving the problem how to dissipate the heat of module.To Solve the problem of heat dissipation,follow below two aspects:1.Based on the analysis of the influence of PCB structure on heat dissipation,chosen the suitable number of layers,copper thickness,stack and heat dissipation holes in PCB.At last,Verified the thermal design of PCB meets the design requirement by using FLOTHERM software to do simulation.2.Based on the theory analysis of cooling effect of the relevant parameters on the heat sink,decided to use the method of orthogonal experimental design to make optimization for the main parameters of heat sink which it will affect the thermal performance of heat-sink,and verified by thermal simulation software FLOTHERM that the optimization can meet the design requirements.Finally,according to the test requirements of the module,set up a test system.This system is used to verify the prototype of the module.The test results show that the output power of the module power reaches 1000 W under the conditions that the wind speed is 200 LFM and above and the ambient temperature does not exceed 45 ° C,which meets the requirements of the project and mass production has been realized.