汽車氙燈之電子安定器設計

Abstract

目前一般汽車所使用的頭燈為60W的鹵素燈，氙燈與鹵素燈比較起來，有發光效率高，演色性高，壽命更長，照明距離更遠，更省電等多項優點。 本論文提出一完整之汽車氙燈之電子安定器設計方法，其架構包括一啟動燈管所需之點火電路，還有提供氙燈正常工作所需能量之反馳式轉換器，以及一全橋式換流電路來避免音頻共振的問題；本論文利用市售的電流模式控制器UC3843晶片來控制反馳式轉換器，並提出斜率補償的辦法，藉著電流模式的上限電流限制值的設計，我們保護了轉換器及氙燈，並以滿足不熄滅的上限電流點亮氙燈。另外我們將燈管穩態時之電路操作點做線性化，並提出一簡單之頻率補償的辦法。硬體方面的架構已經建立起來，實驗結果顯示了燈管正常工作時之電壓電流能與我們的設計規格吻合。

Comparing to the 60W Halogen headlamps used in most of the automobiles present, the new introduced Xenon headlamps have stronger merits in lighting efficiency, color rendering, life time, illustrating distance. This thesis proposes a complete design of the electronic ballast for automotive Xenon headlamps. The whole design includes an igniting circuit, a flyback converter for supplying the operating power of the electronic ballast, and a full-bridge inverter to drive the lamp with square-wave ac power so that the acoustic resonant problem can be eliminated. The flyback converter is of current mode control and driven by UC3843, where a slope-compensator is employed for stabilizing the duty ratio control. The upper current limiter is designed prudently to protect the Xenon headlamp and assure that the lamp can be ignited successfully. The linear system theory is employed to analyze and design the flyback converter. The whole electronic ballast works well and the experiment results just match the theoretical ones.