Research of Piezoelectric Energy Harvesters with Adjustable Resonance Frequency

Autor: Jui-hsin Yu, 余睿昕
Rok vydání: 2016
Druh dokumentu: 學位論文 ; thesis
Popis: 104
Because of the rise in environmental protection awareness, the development of green energy is currently garnering much interest. The efficient conversion of ambient energy into usable electrical energy for replacing traditional electrochemical batteries is a recent trend in research and development. In this study, the resonant frequency of harvested energy was adjusted using a self-tuning mechanism with the goal of approaching maximum power output. We reduce the size and weight of the energy harvester to achieve autonomous power supply for a tire pressure monitoring system. The origin of this study is the design of a uniform cantilever beam for the main body of an energy harvester. The equation of motion is derived from the Lagrange equation to determine the dynamic behavior of the energy harvester. To obtain adequate structural design parameters from the resulting equation of motion, a configuration using an extensible trapezoidal cantilever is proposed. The effective length of the trapezoidal cantilever beam can be extended through centrifugal force from a rotating wheel to vary the area moment of inertia of the trapezoidal cantilever beam. In this study, the variation of area moment of inertia facilitated the adjustment of the harvester’s natural frequency to meet the wheel rotation frequency, obtaining maximum output power. Electrical damping caused by the piezoelectric effect was derived from the energy method and added to complete the equation of motion. A prototype for a piezoelectric energy harvester with natural frequency self-tuning was developed. To investigate the dynamic behavior of the energy harvester, a car wheel emulator was constructed. The experimental output power was 16.9, 19.6, 20.45, and 25.6 μW at 30, 40, 50, and 60 km/hr, respectively.
Databáze: Networked Digital Library of Theses & Dissertations
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