彈性元件耦合多頻寬壓電獵能器設計、製作與性能測試

Design, fabrication and performance evaluation for the elastic elements coupled multi-frequency piezoelectric harvester

賴俊俊(CHUN-CHUN LAI)

指導教授 ： 傅尹坤

國立中央大學/工學院/機械工程研究所碩士在職專班/碩士(2015年)

摘要

本論文中，設計與製作了三種型態的彈性元件耦合多頻寬壓電獵能器，作為振動能量獵能器的應用。透過特徵頻率和阻抗匹配的實驗，以評估三種型態獵能器相關之輸出功率。
A結構型態，以三個螺旋彈簧來支撐壓電懸臂樑，取代傳統的由剛體支持的單自由度壓電懸臂樑獵能器。在振動加速度1.5g時最佳共振頻率為105 Hz，且在最佳負載電阻9.1kΩ時獲得最高的輸出功率10.7 W（瓦）。在振動加速度0.5g時110 Hz被選為最佳共振頻率，且在最佳負載電阻8.2kΩ時獲得最高的輸出功率0.01 mW（毫瓦）。
B結構型態，選用具有回彈性質的金屬薄板，設計其機構特性成為多種彈性體組合而成的可撓性結構，成為多頻寬壓電懸臂樑獵能器。在振動加速度1.5g時有三個最佳共振頻率為30、65和95 Hz時，且在最佳負載電阻68kΩ時獲得最高的輸出功率0.54 W。在振動加速度0.5g時分別在頻率30和65 Hz時出現兩個最佳共振頻率，且在最佳負載電阻91kΩ時獲得最高的輸出功率116.8 mW。
C結構型態，外部使用3D列印技術作成圓柱形的上蓋和底座加以包覆，內部固定鈕扣型大小的環形壓電懸臂樑，也結合彈性螺旋彈簧成為多頻寬壓電懸臂樑獵能器。在振動加速度1.5g時出現一個連續寬峰最佳共振頻率為55至80 Hz，且在最佳負載電阻68kΩ時獲得最高的輸出功率0.41 mW。在振動加速度0.5g時最佳共振頻率為25 和110 Hz時，且在最佳負載電阻100kΩ時獲得最高的輸出功率1.40 mW。
這三種結構型態的壓電獵能器都是兩自由度以上振動體，且實驗結果都獲得多頻寬的共振輸出。因此，可以認定彈性元件的耦合，可提供較寬範圍的共振頻率頻寬。使壓電懸臂獵能器成為多頻寬壓電獵能器，也增強了其獵能性能和頻率的靈活性。

關鍵字

彈性元件 ； 壓電 ； 獵能器 ； 懸臂樑

並列摘要

In this study, three models of elastic elements coupled multi-frequency piezoelectric harvester have been designed and developed as the application of vibration-based energy harvester. Through electrical tuning of the characteristic frequency and impedance matching, the output power of the three models of the harvester has been evaluated.
The Type A model, a new piezoelectric cantilever generator using elastic spiral springs as a supporting mechanism, was fabricated for vibration-based energy harvester application to replace the basic of single-degree-of-freedom (DOF) cantilever generator system supported by a rigid metal bar. Under a base acceleration magnitude of approximately 1.5g, the strongest output power 10.7W was obtained at an optimum load resistance of 9.1kΩ. Under a base acceleration magnitude of approximately 0.5g, the strongest output power 0.01mW was obtained at a optimum load resistance of 8.2kΩ.
The Type B model, a new piezoelectric cantilever generator using elastic metal sheet, was fabricated with multiple flexible materials to provide elastic elements coupled multi-frequency piezoelectric harvester. Under a base acceleration magnitude of approximately 1.5g, the strongest output power 0.54W was obtained at an optimum load resistance of 68kΩ. Under a base acceleration magnitude of approximately 0.5g, the strongest output power 116.8mW was obtained at an optimum load resistance of 91kΩ.
The Type C model, a new piezoelectric cantilever generator using 3D printing to produce a cylinder where the circle cantilever beam is mounted in, was fabricated with elastic spiral spring to provide multi-frequency piezoelectric harvester. Under a base acceleration magnitude of approximately 1.5g, the strongest output power 0.41mW was obtained at an optimum load resistance of 68kΩ. Under a base acceleration magnitude of approximately 0.5g, the strongest output power 1.40mW was obtained at an optimum load resistance of 100kΩ.
The generator could be a 2-DOF vibrating body, which can offer a wide resonance frequency bandwidth. Therefore, it is considered that the elastic spring enhanced the performance and frequency flexibility of the piezoelectric cantilever generator for broadband energy harvesting.

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