寬頻壓電振動能源汲取器之研究

在我們生活周遭常見有低頻的振動能，如汽車行駛時的振動、機具運作時的振動及走路時的晃動等，利用壓電能源汲取器可以將這些振動能轉換成電能輸出，提供給其他裝置使用，因此有許多相關研究因應而生。然而，壓電式能量汲取器的功率輸出往往受限於本身之共振頻率，當振動源的頻率落在非共振區域，則幾乎沒有功率輸出，因此無法穩定地供電。壓電振動能源汲取器在使用上必須要經過外部電路的轉換，所以首先利用有限元素法軟體COMSOL來模擬當壓電懸臂樑接上外部電容後，外部電容對於發電性能的影響，得知懸臂樑輸出電壓與外接電容值成反比，也實際量測壓電懸臂樑接上電容的發電量，其結果與模擬相符。本研究在壓電能源汲取器的基礎上增加了磁力作用，首先以固定式磁鐵作為磁力源，量測磁力對懸臂樑的影響，第二步則是利用兩個末端裝上磁鐵的壓電懸臂樑，耦合壓電原理及磁場效應，使兩個壓電樑相互帶動，進而達到寬頻的效果。由實驗結果可知，固定式磁鐵會改變壓電懸臂樑的共振頻率，相斥的情況下會使共振頻率升高，相吸則使之下降。當運用兩壓電懸臂樑末端磁鐵相互影響時，則可提高壓電懸臂樑的電能輸出，也可將頻寬增加33%。

關鍵字

壓電；能量汲取器；磁鐵；寬頻化

並列摘要

Many kinds of low-frequency vibrations occurs around common life, such as the vibrations of moving vehicles, operating equipments, and walking people. This is why many investigations of piezoelectric vibration energy harvesting appear. In general, the output power of piezoelectric cantilever beam is stored in an external capacitance before supplying loads. Therefore, first of all, the power output of cantilever beams connecting different external capacitors was calculated by utilizing the finite element software COMSOL and investigated experimentally. More importantly, the efficiency of the energy harvester is restricted by its own resonance frequency. Almost no energy is generated at non-resonance frequencies. In this study, we also introduce the magnetic effect into the piezoelectric cantilever beam system to enlarge its bandwidth. The magnetic effect are taken into account with two methods: a fixed magnet as magnetic source and two magnets attached at the ends of two cantilever beams respectively as mass. The experimental result shows that the fixed magnet can only change the resonance frequency of the cantilever beam and does nothing with its bandwidth. The second method successfully increases the bandwidth by 33%.

並列關鍵字

piezoelectric ； power harvesting ； magnet ； broadband

參考文獻

1.P. Glynne-Jones, S.P. Beeby, and N.M. White, “Toward Piezoelectric Vibration-Powered Microgenerator,” IEEE Proceeding Science, Measurement and Technology, Vol. 148, No. 2, pp. 68-72, 2001.

2.F. Lu, H.P. Lee, and S.P. Lim, “Modeling and Analysis of Micropiezoelectric Power Generators for Micro-Electromechanical-

4.S.N. Chen, G.J. Wang, and M.C. Chien, “Analytical Modeling of Piezoelectric Vibration-Induced Micro Power Generator,” Mechatronics, Vol. 16, pp. 379-387, 2006.

5.G.J. Wang, W.C. Yu, Y.H. Lin, and H. Yang, “Modeling and Fabrication of A Piezoelectric Vibration-Induced Micro Power Generator,” Journal of the Chinese Institute of Engineers, Vol. 29, No. 4, pp. 697-706, 2006.

6.F. Goldschmidtboeing, and P. Woias, “Characterization of Different Beam Shapes for Piezoelectric Energy Harvesting,” Journal of Micromechanics and Microengineering, Vol. 18, No. 10, 104013, 2008.

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寬頻壓電振動能源汲取器之研究

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