Design and Implementation of Quasi-resonant Control Circuit and the Adjusting Controller in Primary Side Applied in Chargers

• Main Authors: Yu-Hong - Cai, 蔡宇宏
• Other Authors: Ming-Tse Kuo
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/hmhajm

碩士 === 國立臺灣科技大學 === 電機工程系 === 105 === In this thesis, the lithium battery charging system of a flyback converter was produced. It is different from the traditional charge control by using two groups of feedback control of analog to digital channel to achieve constant current and constant voltage control. In this thesis, using only a group of feedback of primary side adjustment type can achieve constant voltage and constant current charging rules. The overall thesis architecture is divided into three parts. The first part is the flyback converter. This converter operates in AC-DC mode and discontinuous conduction mode. This converter is used and primary side adjustment techniques are incorporated. The output voltage can be feedback through the auxiliary windings. It can eliminate the temperature limit of the traditional optocoupler feedback and reduce cost. The second part is to implement a 5W primary side of the flyback lithium battery charger. The AC input voltage range is from 85V to 265V and full load efficiency is up to 78.77%. The overall system performance is in line with the new Energy Star regulations. The results show that the efficiency can be increased by 4.3% and 3% at high voltage and low voltage, respectively, compared with the existing literature. The third part is a combination of practical and theoretical analysis and provides step-by-step circuit design process and the efficiency improvement program and analysis. Readers can quickly understand and design this circuit architecture and shorten the system design time.