Development Of High Efficiency DC/DC Module Power Supply

With the rapid development of industrial communication industry,the demand of module power supply increases day by day.And the performance indicators of the DC/DC power modules like power density,voltage grade and output power need to be improved.For the module power supply of high power,the efficiency becomes one of the most important indicators.The power density can be improved as the efficiency increases.The calorific value of DC/DC module will be greatly reduced.Therefore,a large number of topological structures and optimization techniques have been proposed.The two level structure of the DC/DC converter due to its high efficiency and wide input voltage ability becomes a research hotspot.To fit the DC/DC module power supply conditions for reference,the thesis summarizes a lot of isolation circuit topology structure,analyses and compares the advantages and disadvantages of them in different application environment.In view of the wide inputting voltage and large current outputting,the Buck-half bridge converter is chosen as the optimal topology for theoretical and experimental research.First,working principle of Buck-Half bridge circuit is analyzed in detail and the design method of the key power components is given.And design control circuit regard LM5041 as PWM control chip.Based on the requirements of the safety and reliability of the DC/DC module power,design voltage and current protection circuit to prevent abnormal input and output voltage and overload damage the power module was designed.To improve efficiency,the transformer winding adopt parallel design to reduce the transformer losses and use planar transformer to save space.The thesis analyses the filter inductance of the buck circuit influencing the power loss,optimal filtering inductance when inputting rated voltage to reduce the loss of the BUCK circuit part;Research the parasitic body diode reverse recovery characteristics of synchronous rectifier,to minimize the parasitic body diode loss generated in the process.According to the above parameters and study,a prototype is made.The rationality of the design parameters and the feasibility of the efficiency optimization measures are verified through the test data of prototype.The index of prototype shows the full load efficiency at the rated input voltage achieves 90%,half load efficiency is as high as 91%.