串並聯混合陣列壓電能量擷取搭配電感並聯同步切換電路之成效比較

Abstract

本論文主要在探討中弱力電耦合的串並聯混合型陣列式壓電能量擷取系統在搭配電感並聯同步切換電路後的成效，並與搭配標準電路時做比較。回顧過去文獻可知，強力電耦合振動子在搭配兩種電路之下成效差異不大，然而，中弱力電耦合或是弱力電耦合就會有明顯的差異。因此若將數根性質近似的懸臂樑壓電振動子之短路共振頻由小到大以一固定間隔差距遞增，則各串並聯型態功率峰值所對應到的頻率能恰巧地被錯開，並搭配頻率偵測與開關控制技術，非常有效的增加了頻寬，與單根懸臂樑壓電能量擷取系統相比，擷取功率也有明顯的提升。 本篇論文以理論解析解開始，並輔以PSpice電路模擬軟體、實際實驗來做驗證，比較在中弱力電耦合之下，串並聯混合型陣列式壓電能量擷取系統在搭配電感並聯同步切換電路以及標準電路之下的成效比較。最後發現，無論是理論預測或是實際實驗結果，都呈現出在搭載電感並聯同步切換電路下，與搭載標準電路之下相比，其各峰功率、平均功率、頻寬上皆有較優良的成效。

The present thesis investigates the behavior of mixed parallel-series connection of weakly coupled piezoelectric energy harvesters attached to the synchronized switch harvesting on inductor (SSHI) circuit. The thesis is motivated by the fact that power of a single piezoelectric oscillator with weak electromechanical coupling is able to be boosted by the SSHI circuit. Hence, the results from the mixed SSHI array are expected to be superior to the standard array system. Specifically, multiple piezoelectric oscillators are prepared such that their natural frequencies are different and sequentially arranged. Thus, the peaks of power of the mixed array with specific electric connection can be tuned to be uniformly distributed and the switching between different array configurations can be realized by frequency sensing and circuit switching techniques. Thus, both power and bandwidth are expected to be further improved if the SSHI circuit is implemented for the case of weak electromechanical coupling. The thesis starts with the development of theoretical model and the derivation of analytic estimate of harvested power. The analytic results are validated by PSPICE circuit simulation. In addition, the experimental validation is preformed and found in good agreement with analytic estimate. The results show there is significant improvement on both harvested power and bandwidth for mixed SSHI arrays in comparison to the standard array system as long as the electromechanical coupling is weak or medium weak.