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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-24 23:12 |
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Conference: Bucharest University Faculty of Physics 2018 Meeting
Section: Physics and Technology of Renewable and Alternative Energy Sources
Title:
Piezoelectric matrix generator for body energy harvesting
Authors:
George ZARNESCU(1), Valentin GIRLEANU(2), Stefan-Marian IORDACHE(1), Ioan STAMATIN(1)
Affiliation:
1) University of Bucharest, 3Nano-SAE Research Centre, P.O. Box MG- 38, Magurele, Romania
2) University of Bucharest, Faculty of Physics, Magurele, Romania
E-mail
stefan@3nanosae.org, zgcnet@yahoo.com
Keywords:
energy harvesting, piezoelectric, piezo-ceramic elements, DC-DC converter.
Abstract:
Piezoelectric materials are widely used now in sensing applications (wireless sensors) or as actuators, for example in an AFM motion control.
In this paper, we propose to use a new (much simpler) technology of fabrication for a piezoelectric semi-flexible long matrix plate. The plate basically has small piezo-ceramic elements encased directly by two PCB copper sheets. The long plate will be used to gather energy from body muscles bending or stretching.
Single piezo-ceramic elements are also characterized mechanically and electrically from the start and selected to be suitable for large plate bendings, mechanically the most important factor is the piezoelectric film thickness and the PCB contact copper plate thickness, respectively 100-200 µm for piezo-ceramics and 600 µm up to 1 mm for copper sheets.
The direct piezoelectric effect is analyzed for two different piezo-ceramic elements used in the device one of 15 mm diameter and the other having 25 mm in diameter (for piezo-ceramic films). Applied bending force (up to 300 mN) was measured for one element and was observed that the generated voltage max. 27 V for a 25 mm element is directly proportional to the applied force, like in theory. Taking into account that the voltage is big enough for an electronic DC-DC converter, piezoelectric elements are linked in parallel connection. The current generated from a single element 200 µA maximum and from the whole matrix is measured and the whole generated power (and accumulated energy in time) is calculated.
The generated signal must be rectified for each piezo-ceramic element separately using SMD Schottky diode bridges because the signals are random and are canceling each other if the diodes bridges are not applied to all elements. To minimize the total device thickness SMD diodes are soldered outside the PCB copper plates.
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