壓電獵能器將環境的振動能轉換為電能並儲存於電容中，通常用來驅動LED或無線發射模組等低耗能元件，近年來由於低耗能電子元件愈趨發展，相關研究開始被提出與重視。而生活環境中存在許多低頻率的外界振動，直接使用壓電材料將振動變為電能，會有轉換效率過低的問題。本研究提出撥動式壓電獵能器，主要利用撥動的方法，讓壓電懸臂樑(換能器)產生自由振盪，從振動行為開始探討其發電特性，進而求出尺寸參數與振動行為的數學關係，並使用壓電方程式計算輸出的電壓，再以電路分析軟體PSIM來模擬撥動壓電換能器對電容充電的行為，最後藉由實驗來驗證每個步驟的正確性，實驗結果顯示此方法在1Hz環境中，獲得的能量比直接換能多了近十倍。本研究另提出「壓電地板」的構想，將此獵能器應用於人行走的地板結構，獵取人行走時造成的振動能量，驅動無線開關裝置需要0.269 mJ的能量，實驗顯示踩踏一次地板可獲得0.277mJ，足以驅動無線發射模組運作一次，本裝置相當適合用於與人互動的創意空間，若搭配處理器來設計接受無線訊號後的行為，未來甚至可應用於智慧建築內。

Piezoelectric energy harvesters are capable of capturing and storing the energy derived from external vibrations. The captured energy can be used to operate low-power electric devices such as LEDs or wireless transmitters. The development of low-power electric devices has recently been advanced, a great deal of research pertaining to this area has therefore been investigated. Examples of low frequency vibrations in daily life include human’s motions, moving train, and flying flags. Such vibrations can be directly converted into electrical energy; however, low efficiency problem may occur. This thesis proposes a piezoelectric energy harvester using plucking force, enabling the piezoelectric cantilever (transducer) to produce free vibrations. The vibration motion is discussed, and the relationship between the parameters and the motion is also derived. The output voltage is then calculated with piezoelectric constitutive equations, and the simulation results obtained via the PSIM program are presented. Finally, experiments are carried out to verify the validity of the proposed research, in which the energy obtained using plucking force was measured to be about 10 times larger than that with direct force. This research also presents the concept of a “piezoelectric floor” which can be applied to floor for energy generation. The harvester can capture the energy generated from human walking. The wireless device needs 0.269 mJ for operation, and the experiment shows that 0.277mJ can be generated by one foot step. The piezoelectric floor can drive an RF tag with one footstep, which is suitable for interactive space applications. If system is designed with processors after receiving the signal, it could be further applied to smart buildings in the future.

[1] http://en.wikipedia.org/wiki/Energy_harvesting
[2] 鄭世裕,壓電材料之發電器應用. Available: http://www.materialsnet.com.tw/DocView.aspx?id=7361
[3] J. Rastegara, C. Pereirab, and H.-L. Nguyen, "Piezoelectric-based power sources for harvesteing energy from platforms with low frequency vibration," in Smart Structures and Materials 2006: Industrial and Commercial Applications of Smart Structures Technologies, San Diego, CA, USA, article number: 617101 (7 pages), 2006.
[4] J. Kymissis, C. Kendall, J. Paradiso, and N. Gershenfeld, "Parasitic power harvesting in shoes," in Second International Symposium on Wearable Computers, Pittsburgh, PA, pp. 132-139, 1998.
[5] N. S. Shenck and J. A. Paradiso, "Energy scavenging with shoe-mounted piezoelectrics," IEEE Micro, vol. 21, no. 3, pp. 30-42, May-Jun 2001.
[6] W. X. Liao, "Design and analysis of a piezoelectric transducer applied to low-frequency electric power generation," master thesis, Mechanical Engineering, National Cheng Kung University, Tainan, 2007.
[7] G. W. Taylor, J. R. Burns, S. M. Kammann, W. B. Powers, and T. R. Welsh, "The energy harvesting eel: A small subsurface ocean/river power generator," IEEE Journal of Oceanic Engineering, vol. 26, no. 5, pp. 539-547, 2001.
[8] A. Erturk and D. J. Inman, "A distributed parameter electromechanical model for cantilevered piezoelectric energy harvesters," Journal of Vibration and Acoustics, vol. 130, no. 4, article number: 041002(15 pages), 2008.
[9] P. J. Cornwell, J. Goethal, J. Kowko, and M. Damianakis, "Enhancing power harvesting using a tuned auxiliary structure," Journal of Intelligent Material Systems and Structures vol. 16, pp. 825-834, Oct 2005.
[10] S. Roundy and Y. Zhang, "Toward self-tuning adaptive vibration based micro-generators," in Smart Structures, Devices, and Systems II, Sydney, Australia, pp. 373-384, 2005.
[11] S. M. Shahruz, "Design of mechanical band-pass filters for energy scavenging," Journal of Sound and Vibration, vol. 292, no. 3-5, pp. 987-998, 2006.
[12] M. Renaud, P. Fiorini, R. V. Schaijk, and C. V. Hoof, "Harvesting energy from the motion of human limbs: the design and analysis of an impact-based piezoelectric generator," Smart Materials & Structures, vol. 18, no. 3, article number: 035001 (16 pages), 2009.
[13] S. Priya, "Modeling of electric energy harvesting using piezoelectric windmill," Applied Physics Letters, vol. 87, no. 18, article number: 184101 (3 pages), 2005.
[14] H. H. Huang, "Design, analysis, and experimental studies of novel PVDF-based piezoelectric energy harvesters," master thesis, Mechanical Engineering, National Cheng Kung University, Tainan, 2009.
[15] E. O. Torres and G. A. Rincón-Mora, "Long-Lasting, Self-Sustaining, and Energy-Harvesting System-in-Package (SiP) Wireless Micro-Sensor Solution," in International Conference On Energy, Environment And Disasters (INCEED 2005), Charlotte, USA, 2005.
[16] http://www.aurelienr.com/electronique/piezo/piezo.pdf
[17] 欒桂冬、張金鐸、王仁乾，壓電換能器和換能器陣，北京大學出版社，2005。
[18] 吳朗，電子陶瓷—壓電，全欣資訊圖書，1994。
[19] S. Priya, "Advances in energy harvesting using low profile piezoelectric transducers," Journal of Electroceramics, vol. 19, no. 1, pp. 165-182, 2007.
[20] Smart Materials Corp.; Available from: http://www.smart-material.com/Smart-choice.php?from=MFC.
[21] D. Shen, S. Y. Choe, and D. J. Kim, "Analysis of piezoelectric materials for energy harvesting devices under high-g vibrations," Japanese Journal of Applied Physics, vol. 46, no. 10A, pp. 6755-6760, 2007.
[22] 蔡永鵬, 光碟機振動預防與對策 Available: http://www.cc.ntut.edu.tw/~wwwmt/print/print-1.htm#4
[23] K. Mossi, C. Green, Z. Ounaies, and E. Hughes, "Harvesting energy using a thin unimorph prestressed bender: Geometrical effects," Journal of Intelligent Material Systems and Structures, vol. 16, no. 3, pp. 249-261, 2005.
[24] eFunda, http://www.efunda.com/home.cfm
[25] C. H. Lin, "Design and fabrication of static force sensor using piezoelectric cantilever beam," master, Mechanical Engineering, National Cheng Kung University, Tainan, 2009.
[26] S. S. Rao, Mechanical Vibrations, fourth ed.: Pearson Prentice Hall, 2004.
[27] J. H. Lin, "A Study of Rubber Admixture in Concrete on Damping Ratio Property," master thesis, Architecture, National Cheng Kung University, Tainan, 2007.
[28] J. M. Gere, Mechanics of Materials, six ed.: Thomson-Engineering, 2003.
[29] D. K. Chen, Field and wave electromagnetics, 2nd ed. Addison-Wesley, 1989.
[30] H. C. Song, H. C. Kim, C. Y. Kang, H. J. Kim, S. J. Yoon, and D. Y. Jeong, "Multilayer piezoelectric energy scavenger for large current generation," Journal of electroceramics, vol. 23, no. 2-4, pp. 301-304, 2009.