Low Frequency Low Voltage Vibration Energy Harvesting Converter

114 Pages·2011·5.53 MB·Danish

Johan Henning Pedersen, s052402
Low Frequency Low Voltage
Vibration Energy Harvesting
Converter
Master’s Thesis, November 2011

Low Frequency Low Voltage Vibration Energy Harvesting Converter,
Report written by:
Johan Henning Pedersen, s052402
Advisors:
Arnold Knott
Ole Cornelius Thomsen
Thomas Andersen
Thomas Sørensen (DELTA)
Peter Spies (Fraunhofer IIS)
In cooperation with
DELTA
Venlighedsvej 4
DK-2970 Hørsholm
Denmark
Website: www.delta.dk
Tel: [phone]
E-mail: [email protected]
and
Department of Electrical Engineering
Electronics Group (ELE) Energiemanagement und
Technical University of Denmark Mikroenergietechnik
Ørsteds Plads, Building 349 Fraunhofer IIS
DK-2800 Kgs. Lyngby Nordostpark 93
Denmark 90411 Nu¨rnberg
Germany
Website: www.elektro.dtu.dk
Tel: [phone] Website: www.iis.fraunhofer.de
E-mail: [email protected] Tel: [phone]
Project period: April 26th, 2011 - November 1st, 2011
ECTS: 30 points
Education: Master of Science
Field: Electrical Engineering
Class: Public
Remarks: This report is submitted as partial fulfilment of the require-
ments for graduation in the above education at the Technical
University of Denmark.
Copyrights: (cid:13)c , Johan Pedersen, 2011

Abstract
This thesis explores the feasibility of a non-linear switching circuit for optimizing low
frequency low voltage vibrational energy harvesting from a Macro Fiber Composite piezo-
electric generator powering a sensor node. This analysis shows that, compared to other
commonly used topologies, the Synchronized Switch Harvesting on Inductor topology is
superior in output power at small vibrations at 2 Hz. The power levels explored in the
project is in the microwatt range, which makes even a small component power loss impor-
tant to take into account.
The performance of the topology at a frequency of 2 Hz and output power levels around
10 µW was found to rise and fall with the peak detection control circuit performance. An
active control circuit based on ultra low power ICs was proposed and a prototype of the
Synchronized Switch Harvesting on Inductor was implemented and tested. The prototype
showed to increase the output power by a factor of two, compared to the standard full
bridge rectifier, but when accounting for the control circuit power consumption of 15.4
µW the gained output power was lost. The control circuit showed to be more of a limiting
factor than expected and a set of requirements for a new control circuit was made. At
higher energy levels the prototype is expected to increase the output energy by up to 8
times and to extend the range of feasible low frequency energy harvesting sources and
applications. This project emphasizes the need for a passive control circuit at power levels
in the microwatt range.
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Resum´e
Idettespecialeudforskesanvendelighedenafetulineærtswitchingkredsløbtilatoptimere
energihøst af lavfrekvent vibrationsenergi ved lav spænding fra en piezoelektrisk generator
afmakrofiberkompositmateriale,derskaldriveensensornode. Isammenligningmedandre
udbredte topologier viser SSHI (Synchronized Switch Harvesting on Inductor) topologien
sig at have en overlegen udgangseffekt ved sm˚a vibrationer omkring 2 Hz. De undersøgte
effektniveauer er i mikrowatt-omr˚adet, hvilket gør det nødvendigt at tage hensyn selv til
sm˚a effekttab i komponenterne. Ved en frekvens p˚a 2 Hz og udgangseffekt omkring 10 µW
vistetopologienspotentialesigatværestærktafhængigafkontrolkredsløbetsperformance.
Derfor blev et aktivt kontrolkredsløb baseret p˚a ultra low power IC’er foresl˚aet og en pro-
totype af SSHI topologien implementeret og testet. Prototypen viste sig at øge udgangsef-
fekten med en faktor to i forhold til en almindelig diodebrokobling, men ved modregn-
ing af kontrolkredsløbets strømforbrug p˚a 15,4 µW forsvandt den vundne udgangseffekt.
Kontrolkredsløbet viste sig at være mere begrænsende end forventet s˚a et sæt krav til
et nyt kontrolkredsløb blev opstillet. Ved højere energiniveauer forventes prototypen at
øge udgangseffekten med op til en faktor 8 og derved at udvide det brugbare omr˚ade af
lavfrekvente vibrationskilder til energihøst og dets anvendelser. Dette projekt fremhæver
behovet for et passivt kontrolkredsløb n˚ar der arbejdes med effektniveauer i mikrowatt-
omr˚adet.
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Preface
This report is a Master’s Thesis in Electrical Engineering at the Department of Electrical
Engineering at the Technical University of Denmark.
The project has been carried out in cooperation with DELTA in Hørsholm, Denmark and
Fraunhofer IIS in Nu¨rnberg, Germany.
Many people have supported me during the writing of this thesis and I would hereby
like to thank all of you. A special thanks to my supervisors Arnold Knott, Ole Cor-
nelius Thomsen, Thomas Andersen, Thomas Sørensen, and Peter Spies for great support
andtoLoretoMatheufromFraunhoferIISforsolidguidanceandinspirationaldiscussions.
Additionally, IwouldliketothankmycolleaguesfromDELTA,Micka¨elLallartfromINSA
in Lyon, France for his helpful correspondence, Rasmus Trock Kinnerup, Stig H¨ogberg,
and Johan Musaeus Bruun, as well as my family for their consistent support.
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Contents
1 Introduction 1
1.1 Energy Harvesting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1.1 Standard Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1.2 Energy Generating Material . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 Energy Harvesting Applications . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2.1 WindSpear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2.2 Running Tights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3 Project Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3.1 Problem Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3.2 Project Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3.3 Thesis Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2 Vibrational Energy Harvesting 7
2.1 Vibrational Energy Harvesters . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1.1 Electrostatic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1.2 Electromagnetic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1.3 Piezoelectric . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.1.4 Comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 The Piezoelectric Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.3 Equivalent Electrical Circuit of Piezo Generator . . . . . . . . . . . . . . . . 11
2.3.1 Macro Fiber Composite Impedance . . . . . . . . . . . . . . . . . . . 12
2.4 Spring Mass Damper Mechanical Model . . . . . . . . . . . . . . . . . . . . 12
2.4.1 Force Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.4.2 Power Delivered to Resistive Load . . . . . . . . . . . . . . . . . . . 15
2.5 Macro Fiber Composite Output Power . . . . . . . . . . . . . . . . . . . . . 16
2.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3 Circuit Topologies for Piezo Harvesting 19
3.1 Impedance Matching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.2 Topologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.2.1 Standard Full Bridge Rectifier . . . . . . . . . . . . . . . . . . . . . 20
3.2.2 Voltage Doubler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.2.3 Synchronized Switched Harvesting on Inductor . . . . . . . . . . . . 21
3.2.4 Synchronous Electric Charge Extraction . . . . . . . . . . . . . . . . 25
3.2.5 Output Power Comparison . . . . . . . . . . . . . . . . . . . . . . . 26
4 Synchronized Switch Harvesting on Inductor Analysis 31
4.1 Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
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