Third order longitudinal mode piezoelectric ceramic transformer and its application to high-voltage power inverter
Third order longitudinal mode piezoelectric ceramic transformer and its application to high-voltage power inverter
复制标题
三阶纵模压电陶瓷变压器及其在高压逆变电源中的应用
DOI：
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
S. Hirose
中科院分区：
文献类型：
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作者：
S. Kawashima;O. Ohnishi;H. Hakamata;S. Tagami;A. Fukuoka;T. Inoue;S. Hirose
彩色液晶显示器（LCD）需要低轮廓，小型化和高效率的功率逆变器，以取代传统的电磁变压器，以照亮其背光，其中包括冷阴极荧光灯（CCFL）。本文的研究目标是实现功率逆变器，其中采用了一种新颖的三阶纵向工作的多层压电陶瓷变压器。为了提高能量转换效率和功率密度，压电变压器在纵向上具有对称结构，其输出部分工作在压电加筋模式下。该变压器有一个很大的优点，所有的电子终端都可以连接在变压器的振动节点上，这有助于保证变压器在高功率运行时性能稳定。该逆变器采用分励振荡电路高效驱动变压器，并通过检测背光电流控制变压器驱动频率，实现对背光亮度的合理调节。采用三层压电变压器制作的逆变器整体效率为92%，输出功率为4.5 W，足以点亮一块9.4英寸彩色LCD，其中包括CCFL安装造成的杂散电容损耗。彩色LCD透光板上的亮度值为2500 cd/m2，而逆变器尺寸小至76×22×6 mm
Color liquid crystal displays (LCD) require low-profile, miniaturized and highly efficient power inverters, replacing conventional electromagnetic transformers, to light up their backlights, which include cold cathode fluorescent lamps (CCFL). The object of this study is to actualize the power inverter, to which a novel multilayered piezoelectric ceramic transformer operating in the third order longitudinal mode is applied. The piezoelectric transformer has a symmetrical structure in the lengthwise direction and its output part operates in a piezoelectric stiffened mode in order to increase both energy conversion efficiency and power density. This transformer has a great advantage, in that all the electronic terminals can be connected at the vibration nodes of the transformer, which contributes to the guarantee of stable transformer performances at high power operation. In this power inverter, a separately excited oscillation circuit was adopted to drive the transformer with high efficiency, and the transformer drive frequency was controlled by detecting the backlight current in order to adjust the backlight luminance properly. Using a triple-layered piezoelectric transformer, a fabricated power inverter exhibited the overall efficiency of 92%, the output power of 4.5 W, which is enough power to light up a 9.4 inches color LCD, including the stray capacitance loss resulted from CCFL mounting. The luminance value on a light transmission plate of the color LCD was 2500 cd/m2 while the inverter dimensions are as small as 76×22×6 mm