Energy harvesting applications to vibrational harvestingluca.gammaitoni/fisen/Document17/21... ·...

Energyharvesting–applicationstovibrationalharvesting

LucaGammaitoniNiPSLaboratory,UniversityofPerugia

Thedevicepoweringissue:

ICT device

Information

Information

1)Howmuchenergyisneededtopoweradevice?2)Wheredoesthedevicegettheneededenergy?

Heat sink

Energy Transducer

Heat sink

Ambient Energy

2

Thedevicepoweringissue: 1)Howmuchenergyisneededtopoweradevice?2)Wheredoesthedevicegettheneededenergy?

Transducer

Heat sink

Ambient Energy

Clearlythisenergyisobtainedfromtheambient…

3

Vibrationsenergyharvesting

Dynamicalmodel

Vibratingbodyz

+ -

x

Energystored

Energydissipated

Energytransd.

m

γ

k

c


Dynamicalmodel

€

m˙ ̇ x = − dU(x)dx

− γ˙ x − c(x,V ) + ζ z

Where:

€

U(x) RepresentstheEnergystored

€

γ˙ x AccountsfortheEnergydissipated

€

c(x,V ) AccountsfortheEnergytransduced

€

ζ z AccountsfortheinputEnergy


Dynamicalmodel

€

m˙ ̇ x = − dU(x)dx

− γ˙ x − c(x,V ) + ζ z

€

˙ V = F( ˙ x ,V )

Equationsthatlinkthevibration-induceddisplacementwiththeVoltage

Detailsdependonthephysicsoftheconversionprinciples…


Dynamicalmodel

€

m˙ ̇ x = − dU(x)dx

− γ˙ x − c(x,V ) + ζ z

€

˙ V = F( ˙ x ,V )

Equationsthatlinkthevibration-induceddisplacementwiththeVoltage


8

Transductionmechanisms

Piezoelectric: dynamical strain is converted into voltage difference.

1

Capacitive: geometrical variations induce voltage difference 2

Inductive: dynamical oscillations of magnets induce electric current in coils 3


€

˙ V = Kc ˙ x − 1τ p

V

€

m˙ ̇ x = − dU(x)dx

− γ˙ x −KVV + ζ z

TheavailablepowerisproportionaltoV2

Piezoelectric: dynamical strain is converted into voltage difference. 1

€

m˙ ̇ x = − dU(x)dx

− γ˙ x − c(x,V ) + ζ z

€

˙ V = F( ˙ x ,V )

ThePhysicsofpiezomaterials

€

˙ V = Kc ˙ x − 1τ p

V


€

m˙ ̇ x = − dU(x)dx


KcandKvdependsonmaterials


Theoscillatordynamics

€

˙ V = Kc ˙ x − 1τ p

V


€

m˙ ̇ x = − dU(x)dx


U(x)isthe“elastic”potentialmechanicalenergyoftheoscillator


Theenvironmentalenergyavailable

€

˙ V = Kc ˙ x − 1τ p

V


€

m˙ ̇ x = − dU(x)dx



Therandomcharacterofkineticenergy

€

ζz Representsthevibration(force)

Whatdoesitlooklike?

At the micro-to-nano scales most of the energy available is kinetic energy present in the form of random fluctuations, i.e. noise.

Thus the challenge is to:

use the noise to power nano-scale devices aimed at Sensing/computing/acting and communicating.

Whatarefluctuationsandhowcanweharvestthem?

Random vibrations / noise Thermal noise Acoustic noise Seismic noise Ambient noise (wind, pressure fluctuations, …) Man made vibrations (human motion, machine vibrations,…)

Alldifferentforintensity,spectrum,statistics

Therandomcharacterofkineticenergy

Vibrationdatabase:RealVibrationsItisveryimportantthatwecancharacterizethespectralfeaturesofthevibrationwewanttoharvest…

VibrationsourcesdigitallibraryThisTaskisdevotedtotherealizationofdatabasecontainingdigitaltimeseriesandspectralrepresentationsofexperimentallyacquiredvibrationsignals.

Signalpresentation:• Description• Powerspectrum• Statisticaldata• Timeseriesdownload(authorizedusers)

www.nipslab.org

realvibrations.nipslab.org

NewAppforcontributingtothedatabase

AvailableontheAppStore:RealVibrations


17

Linearsystems

Ambientenergy

Electricpower

LinearoscillatorThetransferfunctionisamathfunctionofthefrequency,inthecomplexdomain,thatcanbeusedtorepresenttheperformanceofalinearsystem

Foralinearsystemthetransferfunctionpresentsoneormorepeekscorrespondingtotheresonacefrequenciesandthusitisefficientmainlywhentheincomingenergyisabundantinthatregions…

Thisisaseriouslimitationwhenyouwanttobuildasmallenergyharvestingsystem…

VibrationsenergyharvestingFortwomainreasons…

thefrequencyspectrumofavailablevibrationsinsteadofbeingsharplypeakedatsomefrequencyisusuallyverybroad.(1)Thefrequencyspectrumofavailablevibrationsisparticularlyrichinenergyinthelowfrequencypart…anditisverydifficult,ifnotimpossible,tobuildsmalllow-frequencyresonantsystems…

(2)

Acousticnoise–quieteworkingenv.

Microenergyharvestingsystem…

25µmthick1mmhighFreq.10KHz

100µm

CollaborationwithCEA-LETIGrenoble(FR)


Whishlistfortheperfectvibrationharvester

1)  Capableofharvestingenergyonabroad-band2)  Noneedforfrequencytuning3)  Capableofharvestingenergyatlowfrequency

1)  Non-resonantsystem2)  “Transferfunction”withwidefrequencyresp.3)  Lowfrequencyoperated

Theoscillatordynamics

€

˙ V = Kc ˙ x − 1τ p

V

Nonlinearnoiseharvesting

€

m˙ ̇ x = − dU(x)dx


Focusonthepotentialenergy

NON-Linearmechanicaloscillators

€

U(x) ≠ 12ax 2


Example…

Invertedpendulum

m

bimorph piezo-bender

s

strain

tp

tsh

lm

lbm

deflection x

F.Cottone,PhDThesys,Perugia2007

Thisisalinearsystem!


NON-LinearInvertedpendulum

permanentsmagnets

lm

lb

m

Δ

Y

X

ξ(t)excitation

Piezobender

‘xd’deflection

b)

θ

M2

M1

r

hm

http://www.nipslab.org/node/1676

NonlinearEnergyHarvesting,F.Cottone;H.Vocca;L.GammaitoniPhys.Rev.Lett.,102,080601(2009)



NonlinearEnergyHarvesting,F.Cottone;H.Vocca;L.Gammaitoni,PhysicalReviewLetters,102,080601(2009)


€

U(x) =12kex

2 + (Ax 2 + BΔ2)−3 / 2



NonlinearEnergyHarvesting,F.Cottone;H.Vocca;L.Gammaitoni,PhysicalReviewLetters,102,080601(2009)


Duffingpotential

€

U(x) = −12ax 2 +

14ax 4

L.Gammaitoni,I.Neri,H.Vocca,Appl.Phys.Lett.94,164102(2009)

€

bMAX =a2

4D log(τ p )


Monostablepotential

€

U(x) = ax 2n

NonlinearoscillatorsforvibrationenergyharvestingL.Gammaitoni,I.Neri,H.Vocca,Appl.Phys.Lett.94,164102(2009)

Thebenefitsofnoiseandnonlinearity:Extractingenergyfromrandomvibrations,LucaGammaitoni;IgorNeri;HeliosVocca,ChemicalPhysics,Volume375,p.435–438,(2010)


Nanomechanicalnonlinearoscillators

Sketchofamulti-stableoscillatorbasedonclampedmembranes.ThekineticenergyofthenonlinearvibrationisconvertedintoelectricenergybyeitherAlNorPZTmembranesandwichedbetweentheelectrodes.ThevoltageisthenrectifiedbyananodiodeintegratedtotheSOIfilm

30

www.ict-energyletters.eu

In the last three issues we have started a special session devoted to the publication of original scientific papers. Instruction for submission procedure is available at: www.ict-energyletters.eu/submission

NextissueJan15th2015

Whatfutureforthesubjectofenergyharvesting/autonomousdevices?

Focusingonlyonenergyharvestingproducesmisconception.Thefocusshouldbeonenergytransformationprocesses.Bothendsofthegapshouldbeaddressedifwewanttomovefromlabstomarket.

Take-homemessage:

Bright!Theproblemofpoweringsmall(andnotso-small)autonomousdeviceshasbeenalreadyaddressedandsolvedbynature.Thereisplentyofdevicesthatprocessinformation(andactuate)whiletransformingenergyfromlowentropysourcesintoheat.

Noneofthemcarriesdisposablebatteries!

31

-www.nipslab.org-www.ict-energy.eu-Book: ICT-Energy-ConceptsTowardsZero-PowerInformationand

CommunicationTechnology,InTech,February2,2014.

LucaGammaitoni,NiPSLaboratory,UniversityofPerugia(IT)

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