Hemsel T, Priya S
Heinz Nixdorf Institute, University of Paderborn, Fuerstenallee 11, 33102 Paderborn, Germany.
Ultrasonics. 2006 Dec 22;44 Suppl 1:e741-5. doi: 10.1016/j.ultras.2006.05.086. Epub 2006 Jun 5.
Piezoelectric transformers are increasingly getting popular in the electrical devices owing to several advantages such as small size, high efficiency, no electromagnetic noise and non-flammable. In addition to the conventional applications such as ballast for back light inverter in notebook computers, camera flash, and fuel ignition several new applications have emerged such as AC/DC converter, battery charger and automobile lighting. These new applications demand high power density and wide range of voltage gain. Currently, the transformer power density is limited to 40 W/cm(3) obtained at low voltage gain. The purpose of this study was to investigate a transformer design that has the potential of providing higher power density and wider range of voltage gain. The new transformer design utilizes radial mode both at the input and output port and has the unidirectional polarization in the ceramics. This design was found to provide 30 W power with an efficiency of 98% and 30 degrees C temperature rise from the room temperature. An electro-mechanical equivalent circuit model was developed to describe the characteristics of the piezoelectric transformer. The model was found to successfully predict the characteristics of the transformer. Excellent matching was found between the computed and experimental results. The results of this study will allow to deterministically design unipoled piezoelectric transformers with specified performance. It is expected that in near future the unipoled transformer will gain significant importance in various electrical components.
由于体积小、效率高、无电磁噪声且不易燃等诸多优点，压电变压器在电气设备中越来越受欢迎。除了笔记本电脑背光灯逆变器镇流器、相机闪光灯和燃料点火等传统应用外，还出现了一些新应用，如AC/DC转换器、电池充电器和汽车照明。这些新应用需要高功率密度和宽电压增益范围。目前，变压器功率密度在低电压增益下限制为40W/cm³。本研究的目的是研究一种有可能提供更高功率密度和更宽电压增益范围的变压器设计。这种新型变压器设计在输入和输出端口均采用径向模式，且陶瓷具有单向极化特性。该设计能够提供30W功率，效率为98%，从室温起温度升高30℃。开发了一种机电等效电路模型来描述压电变压器的特性。该模型被发现能够成功预测变压器的特性。计算结果与实验结果之间具有良好的匹配度。本研究结果将有助于确定性地设计具有特定性能的单极压电变压器。预计在不久的将来，单极变压器在各种电气元件中将变得极为重要。
