A Novel Contactless Wireless Dimmable LED Driver

• Main Authors: Syu-Hong Chi, 紀旭鴻
• Other Authors: Yi-Hua Liu
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/ywrskr

碩士 === 國立臺灣科技大學 === 電機工程系 === 104 === In this thesis, a novel contactless, low profile and low output ripple dc-to-dc converter is first proposed. A coreless printed-circuit board (PCB) transformer is employed for energy transferring and isolation. To improve the power conversion efficiency, a resonant passive switching module (RPSM) is proposed and embedded in the conventional flyback converter. The presented RPSM module features the characteristic of automatic circuit structure change and boasts advantages such as low output ripple and better efficiency. Due to the lower output ripple, small non-electrolytic capacitors can be used to achieve longer life time. Another special feature of the proposed converter is that simple duty ratio control in the primary side as well as the low switching frequency can be adopted, which allows one to utilize a low cost microcontroller to realize the dimming control. In addition, the voltage conversion gain of the proposed converter can automatically overcome the forward voltage drop of LED strings, which makes it suitable for LED driving applications. To further improve the efficiency, double PWM dimming is also implemented. Finally, ZigBee module is utilized to attain wireless dimming capability. In this thesis, operation principle, theoretical analysis as well as design guidelines of the converter is first provided. A 12 W prototyping circuit is then constructed and the experimental results and measured to validate the effectiveness of the proposed converter. Compared with those of a traditional flyback converter, the efficiency can be improved by 10.84 % with the embedded RPSM, and the output ripple can be improved by 70.96 %.