Piezoelectric Power Harvesting System
Date Issued
2005
Date
2005
Author(s)
Lien, I-Ching
DOI
zh-TW
Abstract
The thesis is to study the development of piezoelectric power harvesting system. The idea is to transfer the vibrating energy of a piezoelectric cantilever beam into the electric energy which can be stored using a series of harvesting circuits. To do it, we develop a harvesting model based on the transformation of the electromechanical coupling energy and use it to find out the key parameters for the optimal design.
The conventional model for piezoelectric power harvesting in literature is to replace the piezoelectric vibrating element with a current source in parallel with its internal electrode capacitance. Such a simplification is questionable since the piezoelectric coupling effect is neglected. On the other hand, we develop a model in this thesis accounting for such coupling effect. We use the technique of eigen-function expansion to derive the governing equations of the piezoelectric vibrator. The whole system is not solvable until the external circuit conditions are included into the vibration equations. In addition, we derive a series of analytic solutions of the model equations and use them to predict the performance of the whole harvesting system.
We also design a series of experiment to validate the harvesting model: the vibrator is connected with several different external loads such as resistance, diodes-capacitance and diodes-capacitance-resistance. Experimental results show that the electromechanical coupling effect has to be taken into account for piezoelectric materials which have large coupling coefficient. The conventional model is suitable only for materials with small piezoelectric coupling coefficient. Finally, we conclude with discussions on the several future directions.
Subjects
能量擷取
壓電材料
能量擷取電路
Power Harvesting
Piezoelectric Materials
Harvesting Circuit
Type
thesis
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