Design of Buck Type Snubber Synchronous Rectification of Full-Bridge Phase-Shift Converter

• Main Authors: Ching-Ho Yu, 游景賀
• Other Authors: Huang-Jen Chiu
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/5xgj53

碩士 === 國立臺灣科技大學 === 電子工程系 === 107 === In the applications of full bridge, phase shift is a most popular architecture. It has an excellent performance on efficiency thanks to soft-switching, especially in high power high voltage applications. However, whether the secondary side uses synchronous rectification or non-synchronous rectification, it will produce the voltage spike on secondary rectifier switches. The voltage spike increases the voltage stress of rectifier switches. This thesis proposes a new type of buck snubber circuit not only to clamp the voltage spike but also to replace the of clamping diode on the primary side because its temperature will be high in light load and increase the power loss. The buck snubber stores the energy of voltage spike into the capacitor and transfers the energy to output which makes the spike energy recovery. By the way, the voltage stress on rectifier switches was reduced, the rectifier switches can be changed as lower voltage stress with lower turn-on resistance. The efficiency of the system will also be increased. In addition, the thesis will compare the difference of clamping point between the rectifier switch and secondary transformer. Finally, the simulation waveform and measure waveform will be used to prove the feasibility of buck snubber and its improvement of efficiency.