Digital Switching Power Supply Based On The Phase-shifted Full-bridge Soft Switching Pwm Converter Research And Design

Now with the social develops and advances constantly, electronic devices are used widely in many areas. The key of electronic devices work safely and reliably is the power supply system. After many years' development, switching power supply has replaced the conventional linear regulator power supply and become the first choice of the power supply system in electronic devices. At the same time, development in new material, technology and other areas promotes switching power supply developing towards high frequencies, digital control, distributed power systems and system integration, etc.In this paper, a breakthrough point is found in switching power supply topology after researching switching power supply's development history and hot topic. In-depth research on phase-shifted full-bridge ZVS PWM converter is done and a new phase- shifted full-bridge ZVS PWM converter is proposed basing on predecessors'research. The new converter, adding a bidirectional switch, not only achieves all switches' ZVS in an extended load, reduces loss of the duty cycle, restrains voltage ringing on the output rectifier diode, but also reduces the circulating current and power loss which are caused by the circulating current and improves the converter's efficienty through controlling the energy which is supplied to the lagging leg for ZVS in the freewheeling by the adding bidirectional switch on the premise of the ZVS of all switches in any load. Meanwhile, APFC, digital control and other technologies are researched. Basing on these researches, a 120K switching power supply of 1200W is designed. The power supply uses UCC28019 produced by TI working in average current mode to achieve APFC and TMS320F2812 to fulfil the digital control of the phase-shifted full-bridge ZVS PWM converter. In order to get more excellent dynamic performance, fuzzy adaptive PID control is introduced.The paper is focused on research and design, detailed circuit design is based on correlative research, and some simulation research is done to verify its correctness and effectiveness.