Document Type

Thesis - University Access Only

Award Date

2012

Degree Name

Master of Science (MS)

Department / School

Electrical Engineering and Computer Science

First Advisor

Steven Hietpas

Abstract

This work involved a determination of the feasibility of using energy scavenging to fully power small autonomous loads that have high availability requirements. An experimental apparatus, referred to as an Energy Scavenging Power Supply (ESPS), was designed to assist in making this determination for one specific application, which involved powering a Fatigue Odometer Sensor (FOS) that operated as a round counter on a large bore weapon. The overall objective was to determine whether any combination of ambient energy sources could be scavenged using real-world transducers and energy control and storage components in such a way as to provide 100% availability in terms of the input energy source (that is, that there would always be enough ambient energy harvested to power the FOS, excluding component/device hardware reliability). The ESPS was designed to harvest energy from vibration, shock, thermal, solar, and electromagnetic energy sources, and to power the FOS in the same fashion as a battery but without the replacement or maintenance requirements. To meet the overall objective, options were explored to determine whether the ESPS could reliably turn on after five minutes of charging and store enough energy after one hour of charging in ideal sunlight to power the FOS in a worse-case operating scenario for 72 hours. Test results indicated that the ESPS could distribute power to the FOS within the five minute operating specification in a broad range of charging conditions, and after one hour of charging in ideal sunlight, the ESPS could power the FOS autonomously for 72 hours. A photovoltaic-to-load energy analy sis was performed to determine what maximum latitude the ESPS could operate at while ensuring 100% availability of power to the FOS if energy was only harvested from a horizontal solar panel in cloudy conditions throughout the day on December 21 st , the winter solstice in the northern hemisphere. Results revealed that the ESPS could provide 100% availability of power operating under this worse-case condition in a range of+/- 60.6 ° latitude while also storing enough energy for 72 hours of sensor autonomy, excluding hardware reliability and considering only input resource intermittency.

Library of Congress Subject Headings

Energy harvesting
Electronic apparatus and appliances -- Power supply

Publisher

South Dakota State University

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Rights Statement

In Copyright