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Title: | 適用於微型與一般型超低耗能與寬頻壓電能量擷取器系統之設計 Designs of MEMS and Bulk-Sized Piezoelectric Energy Harvesting Systems for Ultra Low Power and Bandwidth Extension |
Authors: | Ya-Shan Shih 施雅蘐 |
Advisor: | 吳文中(Wen-Jong Wu) |
Co-Advisor: | Dejan Vasic |
Keyword: | 能量擷取系統,壓電懸臂樑,懸臂樑陣列,寬頻,非接觸式機械同步開關,低耗能, Energy harvesting system,piezoelectric cantilever beam,beam arrays,bandwidth expansion,non-contact mechanical synchronized switch,low power, |
Publication Year : | 2018 |
Degree: | 博士 |
Abstract: | 隨著科技的進步,物聯網(IoT)成為莫可阻遏的趨勢,能量擷取技術也因此成為其核心技術之一。為了使生活中的物品具有感受周遭環境的能力,吾人必須將物品之感測器安裝於其上,以使所有的物品皆具有「感受力」。這樣的感測裝置必須是微型、無線,以便能不著痕跡地安裝在我們的生活物品中。為了維持這些裝置的永續作動,避免頻繁的電源更換(如電池),自供電系統的重要性不言而喻。除了日常生活之外,在健康照護系統、公用建設的健康監測、軍事用途......等,也都有自供電系統的需求。
能量擷取系統提供自供電系統一個從外部環境擷取資源的途徑。能提供能量擷取的環境能量,例如太陽能、溫度差、與各種機械能。其中震動能量擷取被廣為研究,因為震動幾乎是無所不在的。作為機械能擷取的其中一部份,三種常見的方法有: 電磁式、靜電式、壓電式能量擷取。其中又以壓電式能量擷取的能源效率最高。因此,此論文主要探討壓電能源擷取的介面電路與壓電能量擷取裝置之機構設計。 本研究針對壓電懸臂樑能量擷取系統中最常見的能量損耗與頻寬問題,提出了兩種有效的新方式,利用機構與電路的設計,成功的降低同步開關的能量耗損以及增加使用頻段,並探討常用的電子式開關操作在微能源輸入的損耗。並且針對此裝置設計合適的擷取系統:透過懸臂樑陣列、電路研究與機構設計,提升系統效能與頻寬。最後並利用自製的微型壓電懸臂樑配合機電混和開關,以確認所提出的電路在微型能量範圍的可行性。 為建構一個完整的擷能系統,文中主要提出的新方式如下: 一、透過陣列的編排與機構設計,利用磁石的磁性將陣列串聯,達到物理串連,並產生類似多維度機構的效果。 二、利用磁簧開關組成的機械電子混合開關代替同步開關電路中常用的智慧電子式開關(smart switch),以減少電路損耗並能降低閥值損耗。此外,機電混和開關也被成功的應用於輸出電能較一般懸臂樑(cm scale)低的小型懸臂樑(mm scale)。本文中提到的兩種方法能併用,或是分開使用,針對應用情境達到各自的成效。研究中,除了機構設計的模擬與討論,模擬與實驗結果都顯示出此架構增加了能量擷取的效能。另一方面,為克服機械開關的喋喋(chatter)問題,我們提出三種解決方式,並更深入探討同步開關電路中物理開關位置的設計,以利效能的最佳化。 The future trend of Internet of Things (IoT) is bringing energy harvesting in to the core technique due to its requirement of self-power supplying. To realize the IoT, “the ability to sense the world” is the basic requirement of every “thing” in the Internet. That is, each and every object would have its own sensing systems. To achieve this, sensors are installed in the objects. With the aim to retain the user habits, the goal is to keep the “things” in form just as they were. To achieve, additional sensing systems are to be designed small and wireless- they are best to be self-powering. Imagine, if each and every single object in your life has a sensor and all of them requires your attention every few months in different times to recharge the batteries, does that seem like a bright future? Smart house is only one of the reason for self-powered IoT system, not mentioning health care, infrastructure monitoring, and military usages… etc. Energy harvesting provides a way to realize the self-powered system, it enables the device itself to obtain its own energy from their environment. For instance, solar energy, thermal gradient, mechanical forces, are some commonly seen methods to obtain energy from the environment. Among the mechanical energy harvesting techniques, three major methods are used commonly: electromagnetic, electrostatic, and piezoelectric. In this work, a simple model of the original electrical smart switch is proposed. By using the miniature device to drive the smart switch, the efficiency when low power is provided was examined. To construct an energy harvesting system in a more complete aspect, two newly proposed methods are as below: First, the hybrid-electrical-mechanical switches were utilized to replace the commonly seen electrical smart switches, to reduce its energy consumption such as threshold loss. Moreover, the hybrid switch system was also successfully introduced to micro-piezoelectric energy harvesting systems (in scale of mm), which usually has lower energy outputs comparing to bulk sized systems in scales of cm. Secondly, we designed a new mechanical structure for the cantilever array by connecting the beams using magnetic repelling force. In this way, the beams within the array were connected physically, forming a nonlinear multi-degree of freedom (MDOF) -like result. The two methods mentioned above can be applied separately or together, considering the application circumstance. Simulation and experiment was performed, proving the improve of output voltage peaks of the structure. On the other hand, to resolve the inherited chattering of the reed switch, we propose three methods and also further discuss about the effect of the closing time delay of the synchronized switch to optimize the output. |
URI: | http://tdr.lib.ntu.edu.tw/handle/123456789/1304 |
DOI: | 10.6342/NTU201800279 |
Fulltext Rights: | 同意授權(全球公開) |
Appears in Collections: | 工程科學及海洋工程學系 |
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ntu-107-1.pdf | 9.97 MB | Adobe PDF | View/Open |
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