利用軟性電路板製作的駐極體能量擷取器

Abstract

In this thesis, electret energy harvesters and systems were designed and fabricated through the use of flexible printed circuit boards (FPCB). Two sets of harvesters were designed, unit harvester and stacked harvesters. Electret harvester model were constructed by the Matlab/Simulink simulation tool to predict the output power of the devices at different initial gaps and loading resistances. A linearized small signal model was also derived. It can be used for HSPICE simulations with 95 % accuracy at accelerations less than or equal to 0.5 g. The fabricated unit harvester with an initial gap of 310 μm was able to produce 1.93 μW at 1 g acceleration with a resonant frequency of 120 Hz. The fabricated stacked harvester was able to produce 23.06 μW at 2 g acceleration with a resonant frequency of 127 Hz. A prototype of the energy harvesting system was designed utilizing a stacked harvester that operates at 156 Hz and an energy harvesting IC LTC3588-1. Without the power management circuit, the maximum output power at 4 g acceleration was 33.1 μW on a 20 MΩ load. With the power management circuit connected, the energy harvesting system could deliver a regulated voltage burst of 1.8 V within 255 seconds of startup on a 1.5 kΩ load for 15 ms duration. Moreover, the system can deliver power bursts of 2.54 mW at a time interval of 32 s.

本論文使用軟性電路板 (Flexible Printed Circuit Boards , FPCB) 進行能量擷取器及系統的設計及組裝，並使用Matlab / SimuLink，以預估在不同間距及不同負載電阻下的輸出結果，同時也推導出一個可用於HSPICE的線性小訊號模型，其準確度在小於0.5 g的加速度下可達95 %。本論文製作出兩種駐極體能量擷取器，其一為以單層軟性電路板作為可動結構之駐極體能量擷取器，此元件之初始間距為310 μm，且在加速度1 g及共振頻率120 Hz下可產生1.93 μW的功率輸出。而以堆疊三層軟性電路板作為可動結構之駐極體能量擷取器則在加速度2 g及共振頻率127 Hz下可產生23.06 μW的功率輸出。本論文使用共振頻率156 Hz的堆疊能量擷取器及功率管理IC (LTC3588-1) 設計一個能量擷取系統。在尚未加入IC時，4 g加速度及20 MΩ負載的條件下最大可產生33.1 μW的功率輸出；加入IC及1.5 KΩ負載之後，本系統可在啟動255秒之後每32秒產生一個時間長度15毫秒，大小為2.54 mW的能量脈衝輸出。