Research And Implementation Of High Frequency Switch Power Supply

With the development of science and technology, high efficiency, high frequency, green switching power supply now is widely used in many fields. At the same time, the high frequency switching power supply requirements are increasingly demanding, especially in high power field of switch power supply, Compared with conventional converter, the phase-shifted full-bridge converter is more simple, and it is easier to achieve soft switch, and it has many other advantages. In this thesis, the ZVS-PWM-FB converter is studied, and a three-phase AC input DC output5kW switch power supply is completed.The basic switch power supply topology is elaborated in this thesis. Then the ZVS phase-shifted full-bridge converter operational principle is analyzed in detail, and its working characteristic, including zero-voltage condition, the lost of duty ratio, etc.Based on the subject of switch power supply power design indexes, the ZVS phase-shifted full-bridge converter main circuit parameters was come out by the design, mainly including:input filter capacitance, the main transformer, output filtering inductances, output filter capacitance, the selection of power transistors and rectifier diode. Again, based on UCC3895simulation control chip, the control circuit and over-voltage protection circuit were described in this thesis. Finally, A model machine was finished, and through the analysis, The results prove the correction of the theory and the rationality of the design.