壓電功率轉換器及介面電路在能量擷取及結構減震上的應用

Abstract

現今，能源成為了相當重要的議題，從環境當中獲取能源更是受到高度重視。此論文主軸圍繞在透過各種設計來改進壓電能量擷取裝置，希望可與低耗電裝置與無線監測網路結合，來延長裝置電池壽命與直接提供能量為最終目標。機械結構具有高品質因子，當壓電能量擷取裝置操作在遠離共振頻時，輸出功率會快速下降，本論文提出可調變共振頻率的技術，成功的將共振頻率的頻寬延展，獲取更多的能量，此技術也成功的與無線監測網路結合，可在累積足夠能量後將量測資料無線傳出。為了將可用頻寬延展，本論文提出結合非線性雙穩態懸臂樑結構與切換式介面電路的架構，透過永久磁鐵的設計，使懸臂樑成為非線性系統，成功提升在非共振頻時的輸出功率，透過零速度偵測的技術，使切換式電路成功的使用在非線性振動系統當中，由工作週期的討論顯示出兩種技術結合的成果。在低耦合系統中，同步切換為相當成功之介面電路，不同於以往峰值偵測的方式，本論文提出零速度偵測與三片壓電片分流的架構，成功完成自供電同步切換壓電能量擷取系統。當系統為非低耦合時，同步切換技術可應用在系統減震上，最大優點為犧牲少部分減震能力完成自供電減震系統，自供電減震系統的限制與成果透過理論分析、時域與頻率域的結果被成功驗證，整體系統如同回授控制般，當結構振動高於限制時，自供電減震系統將會啟動，並成功的抑制結構振動。

Nowadays with the world oil price soaring, the energy issue is becoming a significant topic and the possibility of harvesting ambient energy receiving much attention. In this dissertation, the main topic surrounds improving the piezoelectric energy harvesting device in several aspects and the final objective is to integrate it with low power consumption device, for example a wireless sensor network node to extend the battery lifetime and further supply the energy to device directly. Based on the high mechanical quality factor of the structure, the output power of the piezoelectric energy harvesting device will decrease rapidly when the exciting frequency is out of the resonant frequency range. The tunable resonant frequency technique is proposed to broaden the resonant frequency range and to increase the output power effectively. Then this technique is successfully combined with a wireless sensor module to transmit the radio frequency signal. To broaden resonant frequency another method is proposed, based on a bistable vibrating cantilever beam and a switching-type interfacing circuit. It is a new and interesting concept to combine these two techniques. The magnets are used to make mechanical behavior non-linear and increase the output power at non-resonance. The synchronized switching technique through zero-velocity detection can work well when system is driven in non-linear system. The experimental and simulation results through work-cycles discussion show good performance of combining these two techniques. Synchronized switching harvesting on an inductor have been verified to be a successful technique to increase output power in low-coupling system. In order to make use of the synchronized switching technique in the real application, the velocity control self-powered system is proposed. Unlike the conventional peak detector technique, the zero-velocity detection is used to make the switching time more accurate. The energy flow is separated into three paths to construct the above-mentioned velocity control self-powered synchronized switching system and the experimental results show good performance. When the system is not low-coupled, the synchronized switching harvesting on an inductor technique will damp vibration. This technique is synchronized switching damping on an inductor. Based on the self-powered technique and zero-velocity detection used in energy harvesting, these techniques are further applied in structural damping to construct a self-powered synchronized switching damping system. The major advantage is that it is only necessary to sacrifice a small amount of damping performance to make the system fully self-powered. The theoretical analysis and experimental results of time domain comparison and frequency response testing show the limit and performance of this technique. The self-powered damping system is like a feedback loop system and when the displacement is over the limit the system will effectively damp the vibration.