微機電技術應用於振動式能量擷取裝置之研製

本研究係研發製作一微機電式能量擷取裝置(energy harvester)，以壓電材料作為媒介，可將環境振動所產生之機械能轉換為電能。不同於傳統壓電式擷能元件中僅利用彎曲應變的懸臂樑設計，本研究採取一雙挾鉗樑(doubly-clamped beam)結構，利用其伸張(tensile stretching)應變效果所產生之非線性勁度，提供元件較為寬廣的操作頻率範圍。在共振結構的設計上，以物理模型的推導配合數值模擬之結果來進行設計。在製程上，以矽晶圓作為基材，利用深式反應離子蝕刻、聚對二甲苯(parylene)氣相沉積、反應離子蝕刻和等向性溼式蝕刻等微機電製程技術，製作出中心具有矽質量塊的軟性聚對二甲苯共振結構，並以適當的封裝技術，使此結構與聚偏氟乙烯(PVDF)壓電薄膜接合，完成整個能量擷取裝置。在共振結構之振動試驗方面，當激振加速度層級為0.1g(g=9.81m/s2)時，於共振頻率451Hz時，具有20.68μm的最大位移量，頻率響應顯示其在更寬廣的頻率範圍內具有相對較大的位移表現，此實驗值亦與模擬結果進行討論和比較。在擷能元件的動態表現及輸出特性的量測上，若施加激振加速度層級為0.5g之振動，元件的共振頻率為615Hz，最大位移量為10.11μm，開路電壓則可達到0.368V，於負載電阻150kΩ時，可輸出0.288μW的最大平均功率。

關鍵字

能量擷取裝置；微機電技術；環境振動；壓電；雙挾鉗樑

並列摘要

In this work, a MEMS energy harvester is designed, modeled and fabricated. The device harvests energy from ambient vibration and convert it to electrical energy via piezoelectric effect. Unlike the traditional designs based on cantilever beams which just use the bending strain, the proposed device utilizes the tensile stretching strain in doubly-clamped beams. This stretching results in a nonlinear stiffness which provides a wide bandwidth of operational frequency. The energy harvester, which consists of flexible parylene vibration structures, a silicon central proof mass and a piezoelectric PVDF film, can be fabricated by using micromachining techniques. The measured frequency response of the resonance structure shows a broader frequency range with large amplitude. The output power harvested from mechanical vibrations is also measured and discussed. When excited at 0.5g (g=9.81 m/s2) acceleration, the energy harvester achieve to a maximum open-circuit voltage of 0.368 V, and a maximum output power of 0.288 μW for a load resistance of 150 kΩ at its resonant frequency of 615 Hz.

並列關鍵字

Energy harvester ； MEMS ； ambient vibration ； piezoelectric ； doubly-clamped beam

參考文獻

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[3] S. P. Beeby, M. J. Tudor and N. M. White, “Energy harvesting vibration sources for microsystems applications,” Measurement Science Technology, Vol. 17, pp. 175-195, 2006.

[4] S. R. Anton and H. A. Sodano, “A review of power harvesting using piezoelectric materials (2003-2006),” Smart Materials and Structures, Vol. 16, R1-R21, 2007.

[5] D. Zhu, M. J. Tudor and S. P. Beeby, “Strategies for increasing the operating frequency range of vibration energy harvesters: a review,” Measurement Science Technology, Vol. 21, 022001, 2010.

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微機電技術應用於振動式能量擷取裝置之研製

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