Research On Phase-shift Full Bridge ZVZCS Converter With Passive Clamp Reset

Nowadays, switching power supply is widely used. It develops in the trendof high performance, high efficiency and high reliability. It is of greatsignificance to make new power supply and research on power supply simulation.Full bridge converter is always used in high power situations. Two typicaltopologies are PWM full bridge converter and phase-shift full bridge converterwhich is also soft switch mode. There are mainly two categories to achieve softswitch: zero-voltage-switch (ZVS) and zero-voltage and zero-current-switch(ZVZCS). ZVZCS is used in this dissertation.Firstly, phase-shift full bridge converter topology is analysed. There are twoways to achieve ZVZC， by adding the aid network to either main circuit orsecond circuit. Several typical structures of ZVZCS converter are also listed inthis dissertation, and at last a new phase-shift full bridge ZVZCS converter withpassive clamp reset is chosen as the main circuit. Secondly, after the analysisthrough half cycle，it turns out that this simple topology can gain excellentZVS in both the leading leg and the lagging leg. Based on analysis above，main circuit parameters of the phase-shift full bridge ZVZCS converter withpassive clamp reset are designed, and appropriate power switch devices arechosen. Drive circuit, sampling circuit, protection circuit of the control sectionare also designed. Furthermore, TI’s TMS320F2812is chosen to processsampling signals, guard signals, and provide the driver phase-shift PWM signals.Software flow charts are designed, and the programs are made based on Clanguage. Finally, MATLAB is used to simulate the system, make the prototypebased on ideal simulation results. From the experiment results, the output voltageand current of the system meet the design requirements, ZVZCS are well realized.