小型振動式發電機之設計與製作

Abstract

近年來，如何將環境中源源不絕之能量轉換成有效能源利用，已逐漸引起世人的興趣。本研究利用壓電材料的性質，擷取週遭環境機械能，並轉換成電能。為了找出最佳發電效果之機構，針對數種不同機構，考量包括壓電彎片數量、彎片架設方式等作理論分析，估計各種不同情況所產生之發電效果，進而將產生的電能做整流電路設計，接著將電能充進鎳氫電池或電容儲存。並且利用系統鑑別得到壓電彎片之頻譜特性，作為設計機構時之依據。本論文設計了利用質量-彈簧系統，配合磁鐵排斥力作用之發電機構，經過有限元素模擬軟體分析及實地測試驗證，發現在5Hz以下之低頻運作環境，較容易激振壓電彎片，增加發電效果。本研究探討了質量-彈簧系統中質量大小對發電效果的影響，並且在馬達搖擺振幅 1.8度，頻率為3.96Hz時量測獲得最佳的振幅2.7伏特和0.379微瓦之發電效果。

Recently, there has been an explosion of interest in the field of transforming the endless energy from ambient vibration into useful power. We scavenge mechanical energy and transfer into electrical energy by utilizing piezoelectric materials. In order to find the optimum mechanism design, we analyze theoretically several kinds of mechanisms concerning the number of piezoelectric benders and the method of erecting benders. We compare generators performance at different situations and then let electric energy be charged to a Ni-MH battery or a capacitor through a full wave rectifier. We also obtain resonance of piezoelectric benders by system identification which can be an important reference when designing the generator. This study proposes a novel mechanism comprising a mass-spring system and magnet repulsive force. According to finite element software and experimental result, below 5 Hz the generator absorbs vibration energy more easily. We have investigated the influence of the mass magnitude and obtained the optimum result of 2.7V and 0.379μw when the swinging amplitude of the motor is deg at swinging frequency of 3.96 Hz.