相位控制之壓電式背光反流器

Phase Controlled Piezoelectric Backlight Inverter

林柏丞(Po-Chen Lin)

指導教授 ： 陳秋麟

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.00208

摘要

背光源系統是液晶平面電視中非常重要的部份，背光源的能源消耗佔了整體液晶電視能源消耗的大部分，隨著平面電視尺寸越大，背光源系統的能量消耗越多，因此將壓電變壓器利用在背光源系統中將可追求更好的能源效率使用，藉以提升整體平面顯示器產業的技術水準。
壓電變壓器是高效率的電能轉換元件，它不但具有更高的安全性而且有更低的電磁波干擾，在體積上還有比傳統電磁式變壓器更薄型化的優勢。但是壓電變壓器的增益在共振頻率才會達到最高的升壓比與效率，所以工作頻率的維持是操作壓電變壓器的重要因素。
本論文針對壓電變壓器在液晶電視背光源系統中的應用進行探討，主要針對壓電變壓器輸出電流與輸入電壓相位差與頻率及增益的關係提出一種相位控制的方式，利用輸出電流相位作為回授控制的訊號以達成壓電變壓器工作頻率的維持，並且以設計的相位控制電路來進行壓電變壓器點亮冷陰極管與外部電極冷陰極管的實驗。

關鍵字

壓電變壓器 ； 背光反流器 ； 相位控制

並列摘要

The backlight system is one of the most important parts in the liquid crystal display (LCD) TV. It consumes most of the power of the whole TV system. Furthermore, the power dissipated by the backlight system increases as the size of the LCD increases. To achieve higher power efficiency, piezoelectric transformers are utilized in the backlight systems.
A piezoelectric transformer can be a high-efficiency power converter. Compared with a traditional electromagnetic transformer, it has many advantages such as higher safety, lower electromagnetic interference (EMI) and smaller volume. However, a piezoelectric transformer has the highest efficiency and the highest voltage gain only when it is operated around its resonant frequency. As a result, it is very important to maintain the operating frequency of a piezoelectric transformer.
This thesis is focused on the application of the piezoelectric transformer in the LCD TV backlight system. The relations between the phase difference of the input voltage and the output current, operating frequency, and voltage gain are discussed. A phase control strategy is also proposed. The control strategy uses the phase of the output current as the feedback signal to maintain the operating frequency of the piezoelectric transformer. We implement the designed phase controlled circuit with piezoelectric transformer to ignite the CCFL and the EEFL.

並列關鍵字

Piezoelectric ； Inverter ； Phase Controlled

參考文獻

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