Design Of The Converter Based On Phase-shifted Full-bridge With Current-doubler And Synchronous Rectifier

In this paper,a high reliability DC/DC converter with 100 V input and 5.5V/50 A output is developed on the basis of phase-shifted full-bridge and current-doubler synchronous rectifier topology.First,the working process of the phase-shifted full-bridge double current synchronous rectifier is analyzed,and the switching behavior of the full-bridge MOSFET and the synchronous rectifier MOSFET is analyzed in detail.The conditions of the zero voltage switch for the full-bridge MOSFET are analyzed,and the dead time design method of the MOSFET driving signal of the forward bridge arm and the lag bridge arm is proposed.Then according to the requirements of the power module technology of concrete,The whole program is designed.respectively to the power stage circuit design,control circuit design,loop stability design and auxiliary power supply circuit design,given the detailed design process and the design of the Saber simulation software is used to test the result.Finally,the structure and PCB were designed,and the engineering prototype product was put into production.The design results were tested and verified on the engineering prototype product,and the test results were given.According to the actual test results,the working state of the prototype is consistent with the design parameters.The full-bridge converter switch operates at zero voltage open state in a wide load range,and the driving time of synchronous rectifier tube is normal and stable,which improves the efficiency of the whole machine effectively.The stability of the product is verified by load step,unload and overload test.The loss of duty ratio is tested,and the results are in agreement with the theoretical analysis.The electric performance of the whole machine is excellent,especially the efficiency index has reached the advanced level of the same kind of product.The successful development of the power supply verifies the rationality of the design method presented in this paper,and further validates the advantages of the phase-shifted full-bridge double current synchronous rectifier in the low voltage and large current converter.