ACTIVE PIEZOELECTRIC ENERGY HARVESTER WITH EMBEDDED VARIABLE CAPACITANCE LAYER AND METHOD OF MANUFACTURING THE SAME
First Claim
1. An active piezoelectric energy harvester comprising:
- a piezoelectric layer generating a voltage by vibration or pressure;
a fixing layer fixing the piezoelectric layer; and
a variable capacitance layer fixed to one region of the fixing layer away from the piezoelectric layer and having a capacitance which varies depending on an applied voltage,wherein the variation in the capacitance of the variable capacitance layer causes a variation in resonance frequency.
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Abstract
Provided is an active piezoelectric energy harvester, which can control a direct current voltage applied to an embedded variable capacitance layer to precisely adjust a resonance frequency in real time, and thus achieve a simpler structure and a smaller size compared to a conventional one that adjusts the resonance frequency using a separate variable capacitor provided outside. Further, the active piezoelectric energy harvester can precisely adjust the resonance frequency even when the frequency of vibration varies over time as in a real natural vibration environment or when it is degraded to undergo a variation in its own resonance frequency, and thus can continuously maintain optimal energy conversion characteristics.
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Citations
11 Claims
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1. An active piezoelectric energy harvester comprising:
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a piezoelectric layer generating a voltage by vibration or pressure; a fixing layer fixing the piezoelectric layer; and a variable capacitance layer fixed to one region of the fixing layer away from the piezoelectric layer and having a capacitance which varies depending on an applied voltage, wherein the variation in the capacitance of the variable capacitance layer causes a variation in resonance frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of manufacturing an active piezoelectric energy harvester, comprising:
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forming piezoelectric layer electrodes on and under a piezoelectric layer, and forming fixing layer electrodes on and under a fixing layer; fixing the piezoelectric layer having the piezoelectric layer electrodes to an upper portion of the fixing layer having the fixing layer electrodes; forming variable capacitance layer electrodes on and under a variable capacitance layer having a capacitance which varies depending on an applied voltage; and fixing the variable capacitance layer having the variable capacitance layer electrodes to one region of the fixing layer away from the piezoelectric layer. - View Dependent Claims (10, 11)
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Specification