Self-Oscillating Flyback Converter with Combined Lossless Snubber and Output-Voltage Sensing Scheme for Contactless Power Supply Applications

• Main Authors: Zhi-YuHuang, 黃植昱
• Other Authors: Ray-Lee Lin
• Format: Others
• Language: en_US
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/74961492106094345216

碩士 === 國立成功大學 === 電機工程學系碩博士班 === 98 === This thesis presents a self-oscillating flyback converter with the proposed voltage-sensing snubber network, whose auxiliary winding is utilized as the lossless snubber inductor and output-voltage sensing winding. For contactless power supplies, the self-oscillating flyback converter provides a cost-effective solution. However, the energy stored in the leakage inductor causes high voltage spike on the switch, and then leads to low conversion efficiency. Therefore, the concept of the lossless snubber is adopted in order to overcome this drawback. Furthermore, in the contactless power supplies, the secondary side of the transformer is isolated from the primary side. Thus, the isolated voltage-feedback scheme is required. The concept of the isolated output-voltage sensing circuit is applicable for the contactless power supply applications to regulate the output voltage. For simplification, the lossless snubber and the output-voltage sensing winding can be combined together as a single winding. A prototype circuit of the 15W self-oscillating flyback converter with the proposed voltage-sensing snubber network is built to verify the performances, such as the voltage stress on the switch, the conversion efficiency, and load regulation.