Research On 5kW Phase-Shift Full Bridge ZVS DC/DC Converter

DC/DC converter is a main part of power electronic converter. As the energy problem increasingly concerned in modern society, improving the efficient and power density have the significant advantages. The developing of power device and invention of soft-switching technique make the high efficient and high power density of DC/DC converter possible.The zero-voltage-switching (ZVS) phase-shift full bridge DC/DC converter is an advanced DC/DC converter with soft-switching technology which can achieve high power converting. Based on the characteristics of the converter, this paper analyses the basic operation theory and some typical problems like secondary duty ratio loss and the parasitic oscillation of output rectifier diodes as well as the difficulty for lagging legs achieve ZVS. The simulation and experiments are also given.Firstly, this paper introduces the background and development of the converter, including power device and soft-switching technology and the hot points in researching DC/DC converter as well as some typical problems and some improvements. Secondly, this paper analyses the basic operation theory and some typical problems like secondary duty ratio loss and the parasitic oscillation of output rectifier diodes and power losses as well as the difficulty for lagging legs achieve ZVS.Thirdly, this paper calculates the main parameters including the selection of bridge MOSFET and the design of transformer as well as the output filter and so on. The last of the third part uses the software SABER to simulate the main circuit to verify the correction of the calculations. Fourthly, this paper introduces the control system of the converter including the UCC2895 chip, sampling circuit, protection circuit, and the small signal model of the converter, as well as the compensation of the feedback loops.Eventually, the paper explains the experimental result and analyzes the result in detail.