Design, Modelling, Fabrication & Testing of a Miniature Piezoelectric-based EMF Energy Harvester
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Date
2014-05-21
Authors
Pollock, Tim
Journal Title
Journal ISSN
Volume Title
Publisher
University of Waterloo
Abstract
Wireless sensing applications have extended into power transmission line monitoring
applications. Minimal power consumption of sensor electronics have enabled kinetic energy
harvesting systems to provides a means of self sustainability in the form of parasitic energy
harvesting from power transmission lines. With this goal in mind, a miniature piezoelectric
bimorph cantilever harvester has been developed using a magnetic tip mass which interacts
with the oscillating magnetic flux surrounding power transmission wires. The focus of
this thesis is develop an analytical model which can be used to optimize the amount
of piezoelectric material to support sensory electronics. Special emphasis has also been
placed on magnet orientation and geometry to ensure optimal magnetic flux interaction
between input and output mechanisms. A single prototype harvester is designed with an
arbitrary piezoelectric material length and experimentally validated at different conductor
wire currents. The analytical model shows excellent agreement in frequency prediction
for the prototype tested. Two damping techniques are used to experimentally extract
modal damping ratios to predict peak mechanical and electrical responses at resonance
frequencies. The miniature prototype design is less than 30 mm in length with only 10 mm
piezoelectric material to produce a total volume of 154 10^-12 cm^3. The power output is
measured at 174.1 W of power when positioned over top a 10 AWG copper conductor a
distance of 6 mm with approximately 16 Amps of current passing though the conductor.
Description
Keywords
Energy Harvesting, Piezoelectric, Electromagnetic Flux, Cantilever Beam, Power Transmission Lines