Date of Award

2017

Document Type

Master Thesis

Degree Name

Master of Engineering (Research)

Department

Electrical & Electronic Engineering

First Advisor

Dr. Martin Hill

Second Advisor

Dr. William Quinn

Abstract

The aim of this project was to develop methods to assess the suitability and reliability of silicon-based piezoelectric micro-electro-mechanicai systems (MEMS) energy harvesters to capture the kinetic energy of the heartbeat in an implanted cardiac pacemaker. The major challenges of the work were that harvesters for vibration frequencies below 100 Hz have not been widely reported and the system requires reliable operation over a long lifetime. In this work device modelling was used for harvester design assessment. Experimental test methods and equipment were developed to produce data to validate the device models and to assess device reliability. A 2D analytical model and a 3D finite element method (FEM) model to predict displacement and power were designed and developed. Three commercial off-the-shelf (COTS) PVDF piezoelectric energy harvesters, were used for model development and validation while the MEMS silicon harvesters were fabricated. The COTS harvesters were also used in the development of experimental test methods and equipment. Tyndall National Institute produced two energy harvester designs and both were analysed under sinusoidal base excitation. Less than 1% error was achieved between modelled and experimental results at resonance. Once validated, the models were used to predict the energy harvester's reliability. Device failure analysis in initial reliability testing, showed good agreement with model predicted behaviour. Finally, the models were used with measured heartbeat acceleration profiles to predict power generation from a human heartbeat.

Access Level

info:eu-repo/semantics/openAccess

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