Page 1
Sheet 1Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
Micro Energy HarvestingPower Supply for Distributed and Embedded Systems
Philipp Bingger and Peter Woias
Albert-Ludwig-University of FreiburgDepartment of Microsystems Engineering (IMTEK)
Laboratory for Design of MicrosystemsFreiburg, Germany
Page 2
Sheet 2Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
WireWire oror batterybattery …… oror whatwhat ??
Sensors in redwood trees© University of California
medical implants© Vitatron
distributed and „embedded“ sensorsystems in greenhouses © Crossbow
tire pressure sensors
sensor
rope
battery service person(vertigo-proof)
Page 3
Sheet 3Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
energyconversion
materialsand
energystorage
energy andsystem
management
Micro Energy Harvesting: The VisionMicro Energy Harvesting: The Vision
heat,light
movement,other bugs,…
Energy-Autonomous Embedded Systems„always on“no battery recharging or exchangeno power cordseasy to install …… at numerous application sites
energy management
micro-sensor
wirelesstransmitter
sensor input
micro-controller
wireless data link
generator energy storage
Page 4
Sheet 4Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
Micro Micro energyenergy harvestingharvesting –– IMTEKIMTEK‘‘ss PhDPhD programprogram
Fact sheetfinanced by DFG and industry3 associated members22+1 PhD scholarhips
start: October 2006run-time: 4.5 years (1st phase)
Associated Members Members Sponsors
Research topicsenergy transduction mechanismsmaterials for energy harvestingenergy storage and managementsystem considerations
Page 5
Sheet 5Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
PiezoelectricPiezoelectric bendingbending generatorsgenerators: : PrinciplePrinciple
11,31 piezodq σ⋅= ( )1131 σ⋅== dtd
dtdqdI
Design challengeshomogeneous mechanical stress higher output powertunable resonance frequency broader application range, more powersmart system integration cheaper, easier fabrication
Page 6
Sheet 6Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
OptimizedOptimized vibrationalvibrational piezopiezo generatorgenerator (2007)(2007)
spectral output power (no seismic mass) influence of a seismic mass
E. Just et al., Proc. GMM-Workshop “Energieautarke Mikrosysteme”, 2006
F. Goldschmidtböing, P. Woias, Journ. Micromech. Microeng. 18, 2008, 104013
Page 7
Sheet 7Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
FrequencyFrequency--tunabletunable piezopiezo generatorgenerator (2008)(2008)
PrincipleActuation force in the „arms“ will stiffen the resonating beam and thus change its resonance frequency
high tuning range (22%)loss of Q factor withincreasing force
C. Eichhorn et al., Proc. PowerMEMS 2008, Sendai, Japan, 309-312.
force
Page 8
Sheet 8Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
FabricationFabrication: : PiezoPiezo--PolymerPolymer--CompositesComposites (2003)(2003)
vent
molding form
piezodisk
piezo disk cured polymer
molding form
liquidthermosettingpolymer
feed
Advantagesstructure definition and piezo integrationin one single steplow-cost perspective via inject moldingextremely high design flexibilityactuators and generators in one single technology
20 mm
piezoceramic diskwith metal electrodes
electrical contact
polymer layer
mounting block
seismic massvibration
Page 9
Sheet 9Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
ImpactImpact--typetype piezopiezo generatorgenerator (2005)(2005)
Advantagesstress-homogenized hinge designfor a maximal output powerhigh output powerhigh output voltagestacked devices for power multiplication
6 mWp @ 36N pulse (100 ms)
M. Wischke et al., Proc. Transducers 2007, Lyon, France, 875-878.
Page 10
Sheet 10Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
ElectromagneticElectromagnetic generatorsgenerators: : PrinciplePrinciple and and examplesexamples
multi-resonant generatorUniv. Hongkong, 2002
P = 800 µWtd
dNU Φ⋅−=
rotatory generator of the Seiko KineticTM wrist watch
P = 5 µW
rotor
generator
batteryelectromechanicquartz clockwork
PropertiesAC currents from motion or induced AC fieldsbad to fair voltage range (mV…V)moderate source impedance (<10 kΩ)
Page 11
Sheet 11Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
ElectromagneticElectromagnetic generatorgenerator in PCB technologyin PCB technology
multi-resonant generatorUniv. Hongkong, 2002
lid
wire-woundcoil
permanentmagnet
spacer
mechanicalresonator
22 mm
Propertiesoutput power: 330 µW @ 102 Hz and 1Gno-load voltage: 210 mV(improved via modified coil design)
E. Bouendeu, J. Korvink, IMTEK – Laboratory for Simulation
Page 12
Sheet 12Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
ThermoelectricThermoelectric generatorsgenerators (TEG): (TEG): PrinciplePrinciple
relevant material combinations α [µV/K]
Al / p-Poly-Si 195Al / n-Poly-Si 110p-Poly-Si / n-Poly-Si 190...320p-Bi0,5Sb1,5Te3 / n-Bi0,87Sb0,13 200...420
TU Δ⋅=Δ α
2TAPp electric
Δ⋅=
Seebeck voltage
Specific output power
Page 13
Sheet 13Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
ThermoelectricThermoelectric generatorsgenerators: : ExamplesExamples
Micro Peltier cooler (photo) and micro-TEG (SEM) © FhG-IPM, MicroPelt
micro-TEG from (1994) for the „Seiko Thermic“(sold in small numbers from 1998 on)
micro-TEG in planar CMOS © Infineon, 2003
polysiliconFOX
cavity
polysilicon
oxidesilicon substrate
cavity
P = 3 µW/cm² @ ΔT = 1..3 K
P = 1 µW/cm² @ ΔT = 5 K
Page 14
Sheet 14Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
3D 3D micromicro--TEGTEG
Output power and no-load voltage @ 10Kmeasured: 1.612 µW
6 V optimization potential: 36.3 µW
top heat conductor (gold)
bottom heat conductor (silicon)
membrane with planarthermocouples (Al-poly-Si)
thermal insulator (SU-8)
air chamber for thermal insulation
T. Huesgen et al., Sensors & Actuators A 145-146, 2008, 523-429.
10 m
m
7500 thermocouples
Page 15
Sheet 15Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
Bio Bio fuelfuel cellscells: : PrinciplePrinciple and and applicationapplication
direct-oxidizingglucose fuel cell
S. Kerzenmacher et al., Journ. Power Sources, 2008A. Kloke et al., Proc. Biosensors 2008, Shanghai
Propertiesoutput power: 2.3 … 3.3 µW /cm²open cell voltage: 0.5 … 0.3 Vpower requirement of a pacemaker: 10 µW
0,0
0,2
0,4
0,6
0,8
1,0
1,2
0 5 10Current density in µA cm-2
Cel
l pot
entia
l in
V
0,0
0,5
1,0
1,5
2,0
2,5
3,0
Pow
er d
ensi
ty in
µW
cm
-2
pacemaker
Page 16
Sheet 16Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
Energy Energy densitiesdensities of of variousvarious storagestorage conceptsconcepts
high storage density of H2 in MHacceptable (and improving) efficiency of H2 fuel cells
Would a „hydrogen battery“make sense ?
0
20
40
60
80
100
Fara
day
effic
ienc
y [%
]
Gold
Cap
Ni-M
H
Li-Io
nH2
fuel
cell
Elec
trolyz
er
Gold Cap
Lead Acid
Adenosine Triphosphate
NiMHLi-Ion
H2 in MH (< 2%)
H2 in MH (4%)
H2 in MH (nanopowder) Methanol
Electrolyte Cap.
1
10
100
1.000
10.000
1 10 100 1.000 10.000
energy density in [Wh/kg]
ener
gy d
ensi
ty in
[Wh/
l]
hydrogen in metal hydrides (MH)
batteries
capacitors
Refs: J. Brodd et al, J. Electrochem. Soc., 151 (3), 2004, K1-K11 and HERA Hydrogen Storage Solutions, Germany
Page 17
Sheet 17Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
chip-integratedfuel cell with Pd storage
HydrogenHydrogen--basedbased energyenergy storagestorage
G. Erdler, M. Frank, M. Lehmann, H. Reinecke, C. Mueller, Sensors & Actuators A 132/1 (2006), 331-336.
volta
ge[V
]
current density [mA/cm²]
pow
er d
ensi
ty[m
W/c
m²]
0.5 mm thick fuel cell:photograph (right) and
its electrical characteristics
6 mm6 mm
19 mm19 mm
Page 18
Sheet 18Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
Energy Energy managementmanagement
Requirementsstart-up controloptimal impedance match betweengenerator, battery and loadvoltage level transformationactive generator controlactive rectificationsupply voltage: < 1 Vpower consumption: a few µW
Solutions, chips ? ….not available today
(2004).
2163 µm
control ASIC for a capacitivemicro converter, Medinger,
Ph. D. thesis, MIT, andAnalog Devices, 1999
….eventuallycoming along
(2009)
Solutions, microchips ?..... not availabletoday ( 2005).
Page 19
Sheet 19Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
Commercial Commercial lowlow voltagevoltage stepstep--upup convertersconverters
0
0,5
1
1,5
2
2,5
3
1970 1980 1990 2000 2010year
star
t-up
volta
ge [V
]
2005: 0.3 Vphotovoltaic cell, TE generator
1998: 1.0 V
charge pumpsinductor-based
Page 20
Sheet 20Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
sensor system
Temperaturesensor
Micro-controller
Energy managementand storage
RF transmitter
Application szenario:
Remote temperaturesensing at „heavy“machinery …
DemonstratorDemonstrator: : RemoteRemote TemperatureTemperature MonitoringMonitoring
Vibration
Temperature ?
Energy-autonomous
Piezogenerator
RF receiver
35,4 °C
35,4 °C
Page 21
Sheet 21Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
System System setset--upup
Requirementswell-defined turn-on and turn-offlow-voltage operationlow-power operation
Page 22
Sheet 22Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
StackedStacked impactimpact--typetype piezogeneratorpiezogenerator
Technical datamaximum output power: 120 µWoptimal output voltage: 2.15 Vtolerance band: ± 0.2 V
Page 23
Sheet 23Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
LowLow--voltagevoltage regulatorregulator withwith sharpsharp turnturn--onon
Characteristicssafe-operation supply voltage: 0.4 V ☺max. power consumption: 25 µWoptimization potential:1…3 µW ☺
Page 24
Sheet 24Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
WhyWhy notnot buybuy …… ??
Problems with today‘s ICsno „real low voltage“undefined sub-thresholdbehaviourlimited functionality (notspecific for energy harvesting)
Page 25
Sheet 25Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
Micro-Embedded Systems and Micro Energy Harvesting
What is it good for ?
Page 26
Sheet 26Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
Automotive Automotive applicationsapplications
engine temperature sensorsair flow sensorsknock sensorstire rotation sensors….solar-powered air conditioningenergy recovery from hot exhaust gases © Alps
lightmotion
accelerationsound and vibration
flowheat
pressuresensor
© Continental
Page 27
Sheet 27Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
Tire pressure monitoring Tire pressure monitoring -- PiezotagPiezotag
mounted opposite the tread power generator (piezoelectric)power management (rectify and smooth)electronics, sensors (p,T) and RF transmitter works at speeds above 15 km/h test 40,000 km → OK
© Piezotag Ltd, England, 2009
Tire Pressure Monitoring Systems
(TPMS)
Page 28
Sheet 28Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
Home and building automationHome and building automation
heat meters at radiatorsautonomous temperature sensorsautonomous lighting sensorsdoor and window surveillanceroom occupancy detection via footstep detectorsventilation control…
autonomous switch © enOcean
lightheat/cold
sound and vibrationflow
Page 29
Sheet 29Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
AISISAISIS--Project (BMBF)Project (BMBF)
Project goalsenergy-autonomous sensor-system for tunnels to determine the damage in case of (explosion, fire,…)energy-harvesting-methods(piezoelectric, thermoelectric, wireless energy transmission )development of high-tensile building materials development of evaluation-models psychological research
project leadership:
5 cm
Page 30
Sheet 30Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
AISISAISIS--Project (BMBF)Project (BMBF)
thermoelectric-conceptgenerator inside tunnel-wallsmall temperature gradients(ΔT = 2 K)optimized thermal coupling
vibration transducer-conceptgenerator on tunnel-wallmechanical → electrical conversionmulti-resonant transducer with optimized mechanical couplingpiezoelectric or electromagnetic
© IMTEK, Germany, 2009
Page 31
Sheet 31Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
„„Daily Daily LivingLiving““, , medicalmedical, , wellnesswellness, , sportssports,,……
forcemovement
flowchem. energy
heat
© Microstrain
stress-controlled prosthesesautonomous sensors and implants (Retina, Cochlear,…) patient monitoring (downfall, faint,…)autonomous sports equipment,…
Page 32
Sheet 32Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
„„ParasiticParasitic““ biomechanicalbiomechanical generatorsgenerators
MIT Media Lab, Boston, USA, 1998
P = 0,25 W© Bionic Power
Burnaby, Canada, 2008P = 5 W
P = 3 W
© Bosch, ca. 1930
Page 33
Sheet 33Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
© Martijn Pater, TU Delft, NL, 2000„Pullman“ MP3-Player
© Chris Aimone and Tomek Bartczak, Toronto, Canada, 2003
„REGEN“ MP3-Player
© Freeplay Energy, UK, 2003crank-powered radio
NonNon--parasiticparasitic““ biomechanicalbiomechanical generatorsgenerators
Page 34
Sheet 34Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
First micro energy harvesters available
Power management system MUST be adapted to the particular generator
Need for low power ICs for power management Well-defined turn-on and turn-offSafe-operationLow power consumption
Conclusion and outlook
Medinger, 1999
Page 35
Sheet 35Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009
Thank you verymuch for your
attention !