Design and Characterisation of a Piezoelectric Bimorph Energy Harvesting Device

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Author(s) Action Nechibvute | Albert Chawanda | Pearson Luhanga
Pages 608-614
Volume 3
Issue 6
Date June, 2013
Keywords piezoelectric bimorph, optimum design, energy harvesting, characterisation

Abstract

The power output of piezoelectric energy harvesting devices can be improved by optimizing the geometry of the device. In this paper, we present our design and experimental results on the electrical power output of a vibration based piezoelectric bimorph device with a proof mass. A geometrical optimization procedure was implemented and the results suggest that the series bimorph device is optimized for power generation when the ratio of the piezoelectric layer length to the proof mass length is 50 %. The optimized device with a volume of 0.678 cm3 was fabricated and its performance was experimentally evaluated. The studies demonstrated that the device was capable of delivering a maximum of 344.67 μW of power to a matched resistive load of 230.6 kΩ, when driven by an ambient mechanical acceleration of 0.45 g at the resonance frequency of 51.5 Hz. This represents a power density of 508 μW/cm3, which is over five times the nominal power density of 100 μW/cm3 required for powering a wireless sensor.

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