旋轉磁場之壓電獵能系統分析

Analysis of Energy Harvester System with Piezo-Patch in Rotating Magnetic Field

鄭勤瀚(Chin-Han Cheng)

指導教授 ： 王怡仁

淡江大學/工學院/航空太空工程學系碩士班/碩士(2021年)

https://doi.org/10.6846/TKU.2021.00421

摘要

本研究將分析一 Fixed-free beam with tip mass 之型態的振動獵能系統的發電效益。此獵能系統的機動裝置，包含橫樑、旋轉盤、彈性鋼片、磁鐵以及壓電片。本系統設計的基本概念為在一Fixed-free beam的自由端置一磁鐵，此磁鐵視為置於beam tip之質量塊，並於此端的對向設一同極性的磁鐵，利用磁極的斥力與樑的彈力相互週期振動，藉此振動，讓裝置在彈性樑上之壓電片達到發電的效果。在理論分析的部分，吾人將會透過非線性尤拉-白努利樑 (Euler-Bernoulli Beam) 模擬橫樑之運動以及多尺度法(Method of Multiple Scales, MOMS) 分析此非線性運動方程式，求解其解析解，並繪製其定點圖以觀察其內共振的可能性，再以數值法加以分析比對解析解之結果。
本研究並以實驗印證理論之正確性。利用雙穩定振動獵能系統 (Bistable Energy Harvester, BEH) 的原理，設計一可應用於行動裝置之轉輪上的發電及儲能裝置，此設計主要有兩個部件，一為可轉動的輪盤上搭載磁性朝圓心的磁鐵，二為固定於圓心之彈性鋼片並裝置壓電片，透過輪盤的轉動使輪盤上的磁鐵磁性交換，對圓心之彈性鋼片上的磁鐵產生斥力，使得彈性鋼片上之磁鐵隨著擺動、並拍擊壓電片，進而產生電力。本文將討論單一彈性樑的振動獵能系統(SESS)及利用雙彈性樑拍擊振動之獵能系統(DESS)，其中SESS為於樑之根部放置壓電片並於前端放置磁鐵，使壓電片受形變以產生電力；DESS為於一彈性樑前端置放壓電片，另一樑之前端放置磁鐵，利用拍擊壓電片以產生電力。透過此實驗，本研究將分別量測壓電片透過形變與拍擊產生的電壓，以此比較兩者之發電效益，並藉由搭配並更換多種不同實驗負載電阻以找到此系統發電的最大功率，最後在與理論值互相驗證，以獲得最後之結論。

關鍵字

非線性振動 ； 獵能 ； 壓電片 ； 多尺度法

並列摘要

This research analyzes the power generation benefit of a fixed-free beam with tip mass Vibration Energy Harvester (VEH) system. The device of this energy harvesting system includes a beam, a rotating disk, an elastic steel sheet, a magnet and a piezo-patch.The concept is that a magnet is placed on the free end of a fixed-free beam. This magnet is regarded as a mass placed on the beam tip, and a magnet with the same polarity is set opposite to this end, using the repulsive force of the magnetic and the elastic force of the beam let the beam vibrate periodically. In the theoretical analysis, this article uses the Euler-Bernoulli Beam to simulate the virbration of the beam and the Method of Multiple Scales (MOMS) to analyze this nonlinear equation of motion to solve the solution and draw its fixed points plot to observe the possibility of internal resonance, and then compare the results of the analytical solution with numerical methods.
This research also verifies the results from theoretical model and experiments. Using the principle of the Bistable Energy Harvester (BEH), a power generation and energy storage device that can be applied to the VEH system is designed. This design mainly has two components, one is a rotating disk The disk is equipped with magnets with magnetism toward the center at it. The second is an elastic steel sheet fixed on the center of the disk and a piezo-patch is installed in the steel sheet. Through the rotating of the disk, the magnet fields on the disk are exchanged, generating repulsive force between the magnet and the elastic steel sheet at the center. The magnet swings and slaps the piezo-patch to generate electricity.This study proposes a single/double elastic steel sheet vibration energy harvester system (SESS/DESS VEH), where the vibration generated by the deformation and/or clap of one/two magnetic excited elastic steel sheet(s) is assisted by a piezo-patch to generate electric energy. This study also measures the voltage generated by the piezo-patch through deformation and tapping. The theoretical and experimental results are correlated and verified. The findings show that power generation benefits of the DESS system is better than the SESS system. The 2nd mode has better power generation than the 1st mode as well.

並列關鍵字

Nonlinear Vibrations ； Energy Harvester ； Piezoelectric patch ； Method of Multiple Scales

參考文獻

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