Study and Implementation of a Dual-Switch Quasi-Resonant Flyback Converter with a Power Factor Corrector
碩士 === 國立臺灣科技大學 === 電子工程系 === 99 === This thesis presents a dual-switch quasi-resonant (QR) flyback converter. Compared with the conventional flyback converter, the design with an extra high-side switch brings many benefits, especially in high input voltage applications. The energy of the leakage in...
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| Format: | Others |
| Language: | zh-TW |
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2011
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| Online Access: | http://ndltd.ncl.edu.tw/handle/hbuzx4 |
| Summary: | 碩士 === 國立臺灣科技大學 === 電子工程系 === 99 === This thesis presents a dual-switch quasi-resonant (QR) flyback converter. Compared with the conventional flyback converter, the design with an extra high-side switch brings many benefits, especially in high input voltage applications. The energy of the leakage inductance is recycled back to the input and there is no need for a snubber circuit. As the switch voltage is clamped at the input voltage, the device stress can be effectively reduced. Also the conversion efficiency is improved due to the low switching losses resulted from the PWM quasi-resonant operations.
The operating principles of the presented converter are discussed. A prototype circuit with an output voltage of 19 V and a rated output power of 90 W is implemented. The front stage is a boost-type boundary-conduction-mode (BCM) power factor corrector (PFC), which enters into the burst-mode operation at light load to reduce the switching losses. The second stage is a dual-switch QR flyback converter operated under discontinuous conduction mode (DCM) to fulfill the valley switchings. Experimental results verify the validity of the theoretical analysis and the practicabilily of the studied converter.
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