高功率零電壓切換壓電變壓器與均流架構設計

Design of High Power ZVS Piezoelectric Transformer and Current Balance Structure

何忠駿(Chung-Chun Ho)

指導教授 ： 李世光

共同指導教授 ： 葉超雄(Chau-Shioung Yeh)

國立臺灣大學/工學院/應用力學研究所/碩士(2009年)

https://doi.org/10.6342/NTU.2009.00202

摘要

本文研究以圓盤型壓電變壓器並聯驅動T5 14W燈管，並設計兩種壓電變壓器，其一為單一輸出電極圓盤型壓電變壓器，須配合均流架構以驅動多根並聯燈管；其二為四輸出電極圓盤型壓電變壓器，雖然四輸出電極壓電變壓器較為複雜，但不須搭配均流電路便可直接驅動四根並聯T5 14W燈管。研究目的是希望以壓電變壓器作為電子安定器以取代傳統的電磁式安定器，並可一次驅動多根並聯燈管，而驅動多根並聯燈管雖然設計較複雜，但卻能節省成本。以往以壓電變壓器作為電子安定器的應用時，功率範圍約在10~20W等級，而本文所用的圓盤型壓電變壓器經測試最高可輸出52.8W。
本文以壓電變壓器的等效電路進行雙埠網路分析來預估壓電變壓器的升壓比、效率…等等的電學特性，同時也以等效電路推導阻抗匹配點。零電壓切換(Zero Voltage Switching, ZVS)也是本文的重點之一，為達到零電壓切換於壓電變壓器前串接一小電感，以其與壓電變壓器之輸入靜電容的共振頻率在壓電變壓器本身共振頻率的1~3倍之間為最佳設計。最後本文以圓盤型壓電變壓器製作具零電壓切換的壓電式換流器，實驗結果顯示，兩種壓電變壓器皆能成功點亮四根燈管。其中，四輸出電極架構的效率為88.9%較電容均流架構的效率82.3%高；但在總輸出功率方面，電容均流架構的總輸出瓦數為52.8W，較四輸出電極架構50.4W略高。而在均流程度則是以電容均流架構較均流，但差異不大。本文的實驗結果顯示以壓電變壓器與均流架構並聯驅動多根T5燈管以取代傳統電磁式安定器是可行的。

關鍵字

圓盤型 ； 壓電變壓器 ； 並聯驅動 ； T5燈管 ； 四輸出電極 ； 電子安定器 ； 零電壓切換

並列摘要

Driving paralleled T5 lamps with disk-type piezoelectric transformers (PT) is the main focus of this thesis. Two kinds of piezoelectric transformer were designed and studied in this thesis. The first one is a single output disk-type piezoelectric transformer which is used with current balanced circuit. The second one is a four output disk-type piezoelectric transformer. Although the second kind is more complex, it can drive four paralleled T5 14W lamps directly without any current balance circuit. The purpose of this research is to substitute conventional electromagnetic ballasts with electronic ballasts using a piezoelectric transformer and driving multiple paralleled T5 lamps. Although the design of driving multiple paralleled lamps is more difficult to design, it could significant lower the cost of ballasts. The power range of piezoelectric transformer based ballast was about 10~20W before, but the power of the disk type piezoelectric transformer in this paper can reach 52.8W.
This thesis also analyzes the electronic characteristics with equivalent circuit of piezoelectric transformer with the two-ports network model. The impedance matching point was derived from equivalent circuit model. To achieve Zero voltage switching (ZVS) condition is one of the main focus in this thesis. To achieve the ZVS condition, a small inductor was series inserted in front of piezoelectric transformer. The optimal value of the small inductor is decided by the resonant frequency of the PT. Specifically, the resonant frequency resonant tank composed of the small inductor and the input intrinsic capacitor of the piezoelectric transformer should be set between one to three times of resonance of piezoelectric transformer. A ZVS inverter based on disk-type piezoelectric transformer has been implemented. The result showed that two kinds of piezoelectric transformers can both light up four T5 14W fluorescent lamps successfully. The efficiency of the four output piezoelectric transformer is 88.9%, which is higher than the efficiency of single output piezoelectric transformer with a capacitors based current balance circuit ─ 82.3%. But the output power of the single output piezoelectric transformer with a capacitor based current balance circuit is 52.8W, which is larger than 50.4W, the total output power of four output piezoelectric transformers. And the current is more balanced in the single output piezoelectric transformer with a capacitor based current balance circuit, but almost the same with the other. The result in the thesis shows that driving multiple T5 lamps in parallel with piezoelectric transformera and current balance circuits to substitute conventional electromagnetic ballast is possible.

並列關鍵字

disk-type ； piezoelectric transformer ； driving in parallel ； T5 lamp ； four output ； ballast ； ZVS

參考文獻

陳昱元，零電壓切換中央驅動雙輸出壓電變壓器用換流器的理論與實驗，國立臺灣大學工學院應用力學研究所碩士論文，2007。

Connection of Radial Mode disk-type Piezoelectric Transformer for Thermal

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E. M. Baker, W. X. Huang, D. Y. Chen, and F. C. Lee, "Radial mode piezoelectric transformer design for fluorescent lamp ballast applications," Power Electronics, IEEE Transactions on, 2005, vol. 20, pp. 1213-1220.

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