2016-08-012024-05-17https://scholars.lib.ntu.edu.tw/handle/123456789/683233摘要：如何獵取各種流失的能量並加以運用，一直是廣受探討的研究議題。近年來，物聯網的發展更激發起無線感測網路的潛在市場。無線感測網路的節點所需之無線感測器一般皆使用電池供應其電力，若能利用能量採集的方式供應其用電，將可免除定時維護的花費，也較電池更為環保。振動能在日常生活中隨處可見且不受天候影響，適合作為能量採集的來源。傳統的振動能量採集器是在懸臂樑上貼附上單面或雙面的壓電材料，在振動下懸臂樑的應變導致壓電材料的表面集結電荷而產生電能。然而懸臂樑採集器之採集頻寬甚窄，導致其應用受到侷限。為了解決此一問題，許多研究利用非線性的方式提升採集性能，主要可分為幾合非線性及非線性力兩種方式。本研究提出一非線性U形壓電振動能量採集器，藉由其幾合非線性增進有效採集頻寬。此外，傳統懸臂樑之固定端與自由端之應變差異甚大，導致其上的壓電材料轉換效率不佳。本研究也將探討此U形採集器之應變分佈，預期其雙邊固定的邊界條件能使應變分佈較為均勻而有良好的轉換效率。研究中也將分析U形採集器在不同的尺寸比例下其採集頻寬以及應變分佈之變化，透澈了解U形採集器特性，以設計出高效率的振動能量採集器。<br> Abstract: Harvesting wasted energy from the environment has always been a focal research topic in the past few decades. Recently, the development trend of internet of things has stimulated the potential of wireless sensor network. Traditionally, wireless sensors rely on batteries as the power source. Using energy harvesting devices instead of batteries to supply the power of wireless sensors will not only costs less on maintenance but also be eco-friendlier. Vibration energy can be easily found in the environment and is not weather-dependent. Therefore, it is suitable for energy harvesting applications. A conventional vibration energy harvester consists of a unimorph or bimorph piezoelectric plate attached to a cantilever beam. When the beam is under excitation, the vibration causes the beam to deform and make the piezoelectric plates to generate electrical energy. However, a cantilever energy harvester suffers from its narrow bandwidth, which limits its applications. In order to overcome this issue, many researchers have developed nonlinear methods to extend the bandwidth for energy harvesting. Two major categories of nonlinearities, geometric nonlinearity and nonlinear force, have been widely discussed and shown the capabilities of enhancing the performance of energy harvesting. A nonlinear U-shaped piezoelectric energy harvester is proposed in this project. It is expected to extend the harvesting bandwidth by its geometric nonlinearity. Besides, the strain difference of a cantilever beam between its fixed and free ends is significant and results in poor efficiency of piezoelectric transduction. In this study, the strain distribution of the U-shaped harvester will also be discussed. The strain distribution is expected to be more uniform due to the boundary condition of the two fixed ends. The influence of the dimensions of the U-shaped harvester on the harvesting bandwidth and strain distribution will be thoroughly discussed and analyzed for the design of high-performance harvesters.能量採集振動壓電energy harvestingvibrationpiezoelectric