Piezoelectric Transducers—Strain Sensing and Energy Harvesting (and Frequency Tuning)
Toshikazu NishidaInterdisciplinary Microsystems Group
Department of Electrical and Computer EngineeringUniversity of Florida
[email protected]://www.img.ufl.edu
2T. Nishida, University of Florida
General Transducer System
Modular Transducer System DesignTransducer
device that converts one form of energy to anotherInterface ElectronicsPackaging/System Integration
Packaging-Protected
Transducer SignalProcessing ActuationControl
Display and/orData System
Interface ElectronicsEx
pose
dEx
pose
d
3T. Nishida, University of Florida
Transducer ClassificationBroad Classification
Energy-ConservingNon-energy Conserving
Specific ClassificationLinear versus nonlinearReciprocal versus anti-reciprocalDirect versus indirect
4T. Nishida, University of Florida
Linear, Conservative, TransducersLinear, energy-conserving, transducers
Linear: linearization about a mean may be requirednecessary for hi-fidelity transduction of time-resolved signal
Energy-conserving: [Ref. Hunt, Electroacoustics, 1954]
Electromechanical coupling methods can be broadly classified according to whether the mechanical forces are produced under the action of electric fields on electric charges or by the interaction of magnetic fields and electric currents.
Five major electromechanical transducers
5T. Nishida, University of Florida
Linear, Conservative, Transducers
1) Electrodynamic: motor/generator action are produced by the current in, or the motion of an electric conductor located in a fixed transverse magnetic field (i.e., voice coil, solenoid, etc.).
2) Electrostatic: motor/generator action are produced by variations of the mechanical stress by maintaining a potential difference between two or more electrodes, one of which moves (i.e., condensor microphone, etc.).
3) Magnetic: motor/generator action are produced by variations of the tractive force tending to close the air gap in a ferromagnetic circuit.
4) Piezoelectric: motor/generator action are produced by the direct and converse piezoelectric effect - dielectric polarization gives rise to elastic strain and vice versa (i.e., tweeters, etc.).
5) Magnetostrictive: motor/generator action are produced by the direct and converse magnetostriction effect - magnetic polarization gives rise to elastic strain and vice versa.
6T. Nishida, University of Florida
Two-Port Model for Linear Conservative TransducerGeneral Two-Port Theory for L.C. Transducers:
In general, represent by simple two-port networks expressed in either the impedance form or the admittance form
Z-representation:
Two-PortElement
I
-
+
-
+V F
U or
EB EM
ME MO
EB EM
ME MO
V Z I T UF T I Z U
Z TV IT ZF U
= += +
⎡ ⎤⎡ ⎤ ⎡ ⎤= ⎢ ⎥⎢ ⎥ ⎢ ⎥
⎣ ⎦ ⎣ ⎦⎣ ⎦
7T. Nishida, University of Florida
Piezoelectric Effect
Prior to poling After poling
33 33 33ES s T d E= +
33 33 33TD d T Eε= +
2 (y)
3 (z)
1 (x)
4 5
6 1-D linear piezoelectric coupling equations
8T. Nishida, University of Florida
Piezoelectric Model
Piezoelectric element modeled as a two-port network
CaD short circuit acoustic complianceCeb blocked capacitanceφ electro-acoustic transduction factor
A
aD
dC
φ −=
( ) dA = electro-acoustic piezoelectric charge modulus [C/N] or [m/V]( )
221A
eb ef efaD
dC C C k
C= − = −
Cef = free capacitancek = coupling factor
CaD
Ceb
φ:1+P-
+V-
9T. Nishida, University of Florida
Strain Sensing
10T. Nishida, University of Florida
Sensing Application: Piezoelectric MicrophoneAeroacoustic applications
Full scale (fly-over) or reduced-scale testing (wind tunnels)Noise source localization with arrays
1000’s of micsCost ($$$/channel)
Harsh environmentsOutdoorsPressurized wind tunnels
MEMS potentialMatched amplitude/phase
Good for arraysReduction in costSmaller size
Ref: Bob Dougherty, “Phased Array Beamforming for Aeroacoustics,” AIAA Short Course, May 8-9, 1999
11T. Nishida, University of Florida
Specifications - Aeroacoustic vs. AudioFrequency Range
Audio20 Hz 20 kHz
AeroacousticFull scale: 45 Hz 11.2 kHz1/nth scale: n*(Full scale)
– ¼ scale: 180 Hz 44.8 kHz
Noise FloorAudio
~ 23 – 37 dBAIntegrated, psycho-acoustic weighted
Aeroacoustic~ 28 - 40 dBNarrow bin for spectral measurement1 Hz bin @ 1 kHz
Acou
stic
Pres
sure
Frequency
Audio Aeroacoustic
Upper Dynamic RangeAudio: ~ 115 - 120 dBAeroacoustic : ~ 170 dB
12T. Nishida, University of Florida
Microphone Choices
“Performance of B&K 4135, size of Kulite MIC-062, cost of SiSonic”
B&K 4135 Kulite MIC 062 SiSonicBandwidth 4 Hz - 100 kHz DC - 125 kHz 30Hz - 10 kHzNoise Floor ~ 5 dB 100 dBA 37 dBAMax SPL (10%) ~ 172 dB 194 dB ~ 124 dBSize 6.35 mm 1.57 mm 3.75 mm x 4.75 mmCost O ($$$) O ($$) O(<$)Type Capacitive Piezoresistive Capacitive
Ref: Kulite Mic-062Kulite Semiconductor Products, Inc.
Ref: B&K Type 4938 Brüel & Kjær
Ref: SiSonicKnowles Acoustics
13T. Nishida, University of Florida
Piezoelectric Microphone Structure
Electrode (Pt or Ti/Pt)
Piezoelectric (PZT)Diaphragm (Si)
Package (Acrylic)
PiezoelectricAnnular
Ring
1.8 mm
TopElectrode
BottomElectrode
SiliconDiaphragm
14T. Nishida, University of Florida
Process Flow - Overview
a)
b)
d)
c)
f)
e)
g)
h)
a)
b)
d)
c)
f)
e)
g)
h)
TiO2SiBuried Oxide (BOX) - SiO2Top Electrode - Pt
PZTBottom Electrode - Ti/PtPhotoresist
15T. Nishida, University of Florida
Packaging & Experimental Setup
Microphone Package
Experimental Setup
16T. Nishida, University of Florida
75 100 125 150 17510
-8
10-6
10-4
10-2
Out
put V
olta
ge [V
]
Input Acoustic Pressure [dB]
DataFit
Experimental Results-Linearity169 dBLinear up to at least
0.75 122.5 1V VSens dB rePa Paμ
= = −
2 0.9995R = Taken at 1 kHzw/ 1 Hz bin
17T. Nishida, University of Florida
Experimental Results-Frequency Response
101 102 103-140
-135
-130
-125
-120
Freq [Hz]
Mag
nitu
de [d
B re
1 V
/Pa]
101 102 103
0
20
40
60
Freq [Hz]
Phas
e [d
eg]
18T. Nishida, University of Florida
SetupTriple Faraday cageSingle point ground
Faraday cages
Experimental Setup-Noise Floor
Sensor
SR785 Spectrum Analyzer
SR560 Low Noise Pre-amplifier
19T. Nishida, University of Florida
1 10 100 1000 1000045
50
55
60
65
70
75
80
85
Freq [Hz]
Mag
nitu
de [d
B re
20 μ
Pa]
Experimental Results-Noise Floor
.
MDS: 47.8 /dB Hz
Setup Noise
Sensor Noise
Noise Floor: 3.7 /nV Hz
Corner frequency (6.7 Hz)
@ f = 1 kHz
[ ]eR MΩ
13.9 1.7
[ ]nFebC
min_avgF 12 nN=
20T. Nishida, University of Florida
10 20 30 40 50 60 70 80 90-20
-18
-16
-14
Mag
nitu
de [d
B re
1 μm
/V]
Freq [kHz]
10 20 30 40 50 60 70 80 90
-150
-100
-50
0
Freq [kHz]
Pha
se [D
eg]
.
Experimental Results-Laser Vibrometry
50.8 resf kHz= 5.4Q =
3 49.3 dBf kHz=
21T. Nishida, University of Florida
Benchmarking
B&K 4135 Kulite MIC 062
SiSonicSP0102
UF PiezoMic
¼ Scale Mic
Bandwidth 4 Hz –100 kHz
DC –125 kHz
10 Hz –10 kHz
18 Hz –49 kHz (theo.)47.8 dB169+ dB5 mm x 5 mm???
Noise Floor ~ 5 dB 100 dB (?) 35 dBA
180 Hz –44.8 kHz
28 dB170 dB
3.8 mm
Max SPL (10%) ~ 172 dB 194 dB (?) ~ 115 dB
Size 6.35 mm 1.57 mm 3.76 mm x 6.15 mm
Cost O ($$$) O ($$) O(<$) O(<$)
Frequency Tuning
23T. Nishida, University of Florida
Tuning and Energy Harvesting Application: Active Acoustic Liner
Aircraft noise is an ongoing environmental problemTwo main sources
Airframe noisePropulsion noise
Comparison of the Approach Noise Levels for the Boeing 747-400 with Pratt & Whitney 1992 Technology Engines and ADP Engines (NASA/TM-2005-212144, May 2005)
60 70 80 90 100 110
Total Aircraft Noise
Total Airframe
Jet
Turbine
Combustor
Aftfan
Inlet
EPNdB
P&W ADP Engine P&W 1992 Technology Engine
24T. Nishida, University of Florida
Active Acoustic Liner - Background
Ref. Rolls Royce, “The Jet Engine”, 1986.
Aircraft engine duct linersProvide impedance boundary conditions for engine ductMinimize the radiation of noise from the duct
Existing liner technologyPassive acoustic linerActive acoustic liner
Desirable traits of an acoustic liner
Tunable impedance, wide bandwidth, robust, light-weight, inexpensive, etc.
25T. Nishida, University of Florida
Self-Powered, Wireless Acoustic Liner Concept
( )U n
controller &communications
energyreclamation
module
tunableelectromechanical
liner cellmicrophones
( ) ( ) ( ), , i t k rp r t p k e ωω − ⋅′ ′=r rrr
n
controller &communications
Acoustic liner specifications
Tunable Helmholtz resonator for impedance modification Energy reclamation module for self-poweringWireless control module for remote tuning
26T. Nishida, University of Florida
Lumped Element Model for Conventional HR
( )2
4
kg, 1 2 m
airaDrad
eff
ka cR ka
A sρ ⎡ ⎤≅ ⎢ ⎥⎣ ⎦
4
8 kg, 1 3 m
airaDrad
eff
ka cM ka
Aρ
πω⎡ ⎤≅ ⎢ ⎥⎣ ⎦
Radiation impedance modeled as a piston in an infinite baffle
Plate parameters found from deflection curve,
( )2
00
0
2R
P
AP
w r rdrVoldV V
π→
→
Δ= =
∫
( )2
00
0
2R
V
aDV
w r rdrVolCP P
π→
→
Δ= =
∫2 2
0
( )2R
aD Aw rM rdrVol
ρ π ⎛ ⎞= ⎜ ⎟Δ⎝ ⎠∫
( )w r
27T. Nishida, University of Florida
Tunable Electromechanical Helmholtz Resonator
Electromechanical Helmholtz resonator (EMHR)
Piezoelectric composite backplate (PZT-backplate) instead of conventional solid-wallShunt-loads across the PZT-backplateEM DOFs possible
aNR aDCaNM
aCCaD aDradM M+
Q
INZP EBC LZ
:1φ'Q i
+
−
'P
aDradR
Ref. APC International, Ltd.
28T. Nishida, University of Florida
Tuning Performance of EMHR
2 DOF/3DOF: coupled oscillatorShort circuit and open circuit define the capacitive and resistive tuning− 9%
Inductive tuning is not limited to short-circuit and open circuit− >19%
Energy Harvesting
30T. Nishida, University of Florida
Meso Acoustic Energy Harvesting - Overview
PowerConverter
Circuit
Acoustic Energy
Pin
Acoustic to ElectricalConversion
PHR
Pin
ElectricalConditioning
Electrical Energy
HelmholtzResonator
Pout
PHR
Pout
31T. Nishida, University of Florida
Meso Acoustic Energy Harvester – LEM
aNR aDCaNM
aCCaD aDradM M+
Q
INZP EBC LZ
:1φ'Q i
+
−
'P
aDradR
Electromechanical Helmholtz resonator (EMHR)
Piezoelectric composite backplate (PZT-backplate) instead of conventional solid-wallEnergy harvesting circuit across the PZT output
Same equivalent circuit as tuning circuit
PZT-backplateEH Circuit
Cavity
Neck
Ref. APC International, Ltd.
32T. Nishida, University of Florida
Meso Acoustic Energy Harvester – Power vs Load
RLoad
Cbulk
iLoad
VLoad
Load Power(VLoad)
2/RLoad
HR Output • The HR is connected to a rectifier bridge, bulk capacitor and load resistor.• The HR is driven at the resonance of the diaphragm.• The bulk capacitor and load resistor are both swept, the power at the load is measured.
Experimental Load Power vs. Resistance
0
0.3
0.6
0.9
1.2
1.5
0 20000 40000 60000 80000 100000
Resistance (ohms)
Pow
er (m
W)
0 nF 1 nF 10 nF 100 nF 1000 nF
33T. Nishida, University of Florida
Meso Acoustic Energy Harvester – SetupAcoustically excited Plane Wave Tube (PWT)
B&K Pulse SystemTechronAmplifier
Cavity Mic.
Mic.2Mic.1
Incident Mic.
EnergyHarvestingDevice (or
Loads)
Speaker PWTPiezoelectric backplate
Helmholtz resonator
Δ
1x
34T. Nishida, University of Florida
Meso Acoustic Energy Harvester – Results
Output Power vs. Incident Pressure
0
5
10
15
20
25
30
130 135 140 145 150 155 160
Incident Pressure (dBSPL)
Out
put P
ower
(mW
)
4.7mH Linear Regulator Direct Charging
35T. Nishida, University of Florida
Energy HarvestingAdvantages
Simplifies deployment of a large numbers of wireless sensorsAvoids need for routing or retrofitting wiringEliminates maintenance costs of battery replacement
ChallengesAmbient waste energy not necessarily dependableHarvestable energy scales down with decreasing volume
Smaller size → less available energy
36T. Nishida, University of Florida
Energy Sources for Distributed SensorsSource Power Density
(μW/cm3)Energy Density(J/cm3)
Primary Battery 2880Secondary Battery 1080Ultra-Capacitor 50-100Micro-fuel cell 3500Heat Engine 3346Radioactive 0.52 1640Solar (Outside) 15000*Solar (Inside) 10*Temperature 40*a
Human Power 330Air Flow 380b
Pressure Variation 17c
Vibrations 300
* Denotes sources whose fundamental metric is area.
Notes:a) Demonstrated from a 5°C
temperature differential
b) Assumes air velocity of 5m/s and 5% conversion efficiency
c) Based on 1cm3 closed volume of helium undergoing a 10ºC temperature change once per day.
Roundy, S., Wright, P. K., and Rabaey, J., Computer Communications, 26(11), pg1131-1144
37T. Nishida, University of Florida
Energy Harvesting ApplicationLocally-powered wireless hydrogen sensor
(2) Harvestable energy scales down with decreasing volume
⇒ Multiple sourcesVibrationSolar
⇒Balancing power budgetPower consumption (dissipation)Power generation
(1) Ambient waste energy not necessarily dependableChallenges addressed as follows:
Carbon fiber reinforced H2gas tank, Photo: Quantum Technologies
Liquid H2 storage tank at NASA KSC, Photo: D. Wood
38T. Nishida, University of Florida
Block Diagram of Self-powered Sensor System
Solar Cell
Piezoelectric
Energy Reclamation
Circuit
Energy Storage
Available Power
Power Generation (Energy Harvester)
Sensor Microcontroller Transmitter
Power Dissipation (Loads)
Solar Cell
Piezoelectric
Energy Reclamation
Circuit
Energy Storage
Available Power
Power Generation (Energy Harvester)
Sensor Microcontroller Transmitter
Power Dissipation (Loads)
39T. Nishida, University of Florida
H2 Sensor
S D
ZnO M-NRs
Al2O3 Substrate
Al/Pt/AuS D
ZnO M-NRs
Al2O3 Substrate
Al/Pt/Au
Power considerationsConventional
Pd-SiC Schottky diodes– Require on-chip heater
Nano-structure-basedPt-catalyst coated multiple-ZnO nanorod
– Room-temperature low-power operation (O(100 μW))
0 5 10 15 20 25 30
0
2
4
6
8
10Air10~500 ppm H2
Pt-ZnO nanowires500ppm250ppm100ppm10ppm
Time(min)|Δ
R|/R
(%)
Recent result: single Pt-coated ZnO nanorod– 10x lower power and 3x faster response
Ref. Wang et al., Appl. Phys. A, 81, p. 1117, 2005.
40T. Nishida, University of Florida
Differential Hydrogen Detection
+
-
-
+
-
+
VDD
GNDGNDEx
pose
d Zn
O
Pass
ivat
edZn
OR
Bia
s
R B
ias
R1
R1
RG
R2
R2
R3
R3
VOUT
+
-
-
+
-
+
VDD
GNDGNDEx
pose
d Zn
O
Pass
ivat
edZn
OR
Bia
s
R B
ias
R1
R1
RG
R2
R2
R3
R3
VOUT
Wheatstone bridgeDifferential H2 signal
Exposed m-ZnO vs. sealed m-ZnO
41T. Nishida, University of Florida
Controller Considerations
SLEEP
SLEEPTransmitData
AcquireDataSLEEP
SLEEPTransmitData
AcquireDataSLEEP
SLEEPTransmitData
AcquireData
Selection factorsActive currentStandby currentWakeup timePort leakageADC precision
NA1uA in hibernating mode
0.1uA in sleep mode
10uA@32kHzXEMICS XE88LC01A
NA0.6uA standby0.1uA sleep
9uA@32kHzEM Micro EM6617
1uA5 Sleep modes, lowest is 0.2uA
27uA@32kHzAtmel Atmega169
25nA3 Stop modes: from 4.3uA to 25nA
812uA@1MHzMotorola MC9S08G
1uA1uA20uA@32kHzMicrochip PIC16F73
50nA4 low power modes from 0.7uA to 0.1uA
14uA@32kHz, 2.5uA@4kHz and 2.2V
TI MSP430F1122
Port Leakage
Standby CurrentActive CurrentManufacturer and Model
NA1uA in hibernating mode
0.1uA in sleep mode
10uA@32kHzXEMICS XE88LC01A
NA0.6uA standby0.1uA sleep
9uA@32kHzEM Micro EM6617
1uA5 Sleep modes, lowest is 0.2uA
27uA@32kHzAtmel Atmega169
25nA3 Stop modes: from 4.3uA to 25nA
812uA@1MHzMotorola MC9S08G
1uA1uA20uA@32kHzMicrochip PIC16F73
50nA4 low power modes from 0.7uA to 0.1uA
14uA@32kHz, 2.5uA@4kHz and 2.2V
TI MSP430F1122
Port Leakage
Standby CurrentActive CurrentManufacturer and Model
42T. Nishida, University of Florida
Modes of OperationMSP430 configuration
Minimum supply voltage (2.2V)32 kHz external clockInterrupt-driven control, most of CPU shutdown to conserve power
Level monitoringConstantly monitors H2 sensor and only sends emergency RF pulse above preset emergency threshold
Data transmittingConstantly monitors H2 sensor and sends data periodically, except if sensor value exceeds preset emergency threshold
43T. Nishida, University of Florida
Wireless Transmission
VDD
GND
VDD
GND
TradeoffsLow-level communication protocol
Low overhead for transmitterHigh overhead for receiverLow functionality for multiple sensors, networking, etc.
High-level communication protocolHigh overhead for transmitterLow overhead for receiverHigh functionality
Simple Colpitts oscillatorOn/Off Keying300 MHzData shifted bit-by-bit from output port to input
44T. Nishida, University of Florida
Power Budget
Average PowerResistanceHydrogen Level
88.6 uW1500 Ohms500 ppm
84 uW1563 Ohms0 ppm
Average PowerResistanceHydrogen Level
88.6 uW1500 Ohms500 ppm
84 uW1563 Ohms0 ppm
Controller/ transmitter
H2 sensor
20 m transmit distance w/ quarter-wave antenna
Power generation targetVibrationSolar
Variable2.5 uWRemain Idle
0.5ms per bit2.5 uWTransmit 0
0.5ms per bit261 uWTransmit 1
0.3 ms per bit2.5 uWSense Data
12.5ms3.07 mWInitialization
Length in TimeAverage PowerEvent
Variable2.5 uWRemain Idle
0.5ms per bit2.5 uWTransmit 0
0.5ms per bit261 uWTransmit 1
0.3 ms per bit2.5 uWSense Data
12.5ms3.07 mWInitialization
Length in TimeAverage PowerEvent
45T. Nishida, University of Florida
Mesoscale Piezo-Cantilever Power Generation
D1
D3 D4
D2
VBattery
PZTBimorph-4 C
IBattery
+
-A
R
Piezoelectric cantilever
Piezo Systems, Inc. D220-A4-203YB (32 mm x 6.4 mm x 0.3 mm)
displacement
acceleration
OPTICAL TABLE
Clamp plate
Proof mass
PZT composite beam
Mm & Cms
voltage
Power Amplifier
SHAKER
Spectrum Analyzer Imp. Head
displ. sensor
0
50
100
150
200
250
300
0.00 0.20 0.40 0.60 0.80 1.00 1.20
RMS Acceleration [/g]
Pow
er D
eliv
ered
to B
atte
ry [u
W]
46T. Nishida, University of Florida
Power Generation—Solar
1.5mm
ConverterController
Charge Pump
13 1215 14
Controller
Testing Schematic (Solar)
vds2 vds
Vbattery
PGateNGate
Solar Panel
vin
NGate
-PGate
Cin
Battery/Load
8 710 9111617
1819
2021
2223
65
43
21
24
25
26 29 30
40
2827
GndSmallSolar Panel
+
-
+
-
L=100uH
Voc
VrefH
Override_N
Enable_N
Override_PEnable_P
3931 …
1.5mm
ConverterController
Charge Pump
1.5mm
ConverterController
Charge Pump
13 1215 14
Controller
Testing Schematic (Solar)
vds2 vds
Vbattery
PGateNGate
Solar Panel
vin
NGate
-PGate
Cin
Battery/Load
8 710 9111617
1819
2021
2223
65
43
21
24
25
26 29 30
40
2827
GndSmallSolar Panel
+
-
+
-
L=100uH
Voc
VrefH
Override_N
Enable_N
Override_PEnable_P
3931 …
Custom DC-DC converter designed and testedMaintains output voltage near optimal voltage for maximum output power independent of load
High efficiency c-Si solar cells (IXYS Semiconductor XOD17-04B
47T. Nishida, University of Florida
System Integration and Test
ZnO H2 sensor
Self-powered Controller/Tx
N2
500 ppmH
2
Rx/laptop
ZnO H2 sensor
Self-powered Controller/Tx
N2
500 ppmH
2
Rx/laptop
Operation confirmed using mechanical shaker and external lightLevel monitoring modeData transmission mode
Informal vibration application testVacuum pump surface
Vibration Energy Harvesting Piezo Cantilever
Modeling assumptionsLinear Euler-Bernoulli beam theoryPerfect bond assumptionLinear piezoelectric material and reciprocal system
49T. Nishida, University of Florida
Electromechanical LEM
Lumped Element ModelingAnalytical : provides scalingCircuit : enables complete electromechanical system simulation
F
Mm Cms
CebU
φ : 1
EffectiveCompliance of
Beam
EffectiveMass ofBeam
InputForce
Velocity
ElectromechanicTransduction Factor
BlockedElectrical
Capacitance ofpiezoceramic
I
V
Current
Voltageacross the
piezoceramic
Re
Mechanicaldamping of
beam
Dielectric lossin the
piezoceramic
Rm
MEMS Energy Harvesting
51T. Nishida, University of Florida
Final structure (front view and top view) Not drawn to scale
SiO2
SiSiO2(BOx)
Ti/Pt PZTPt
Bond pads
Proof mass
Clamp
Cantilever Beams
Au
MEMS Piezoelectric Cantilever
52T. Nishida, University of Florida
MEMS Piezo Cantilever DevicesSEM pictures of released devices
Device DimensionsPZT-EH-09PZT-EH-07
500 μm
4 mm
2.5 mm
1 μm
1 mm
1 mm
12 μm
1 mm
1 mm
1 μmThickness of PZT
1.8 mmLength of proof mass
2.4 mmWidth of proof mass
500 μmThickness of proof mass
0.5 mmWidth of PZT
0.5 mmLength of PZT
12 μmThickness of beam
0.5 mmWidth of beam
0.5 mmLength of beam
Device DimensionsPZT-EH-09PZT-EH-07
500 μm
4 mm
2.5 mm
1 μm
1 mm
1 mm
12 μm
1 mm
1 mm
1 μmThickness of PZT
1.8 mmLength of proof mass
2.4 mmWidth of proof mass
500 μmThickness of proof mass
0.5 mmWidth of PZT
0.5 mmLength of PZT
12 μmThickness of beam
0.5 mmWidth of beam
0.5 mmLength of beam
PZT-EH-07
PZT-EH-09
53T. Nishida, University of Florida
MEMS Piezo Generator - ArrayArray of MEMS piezo generatorsSeries and parallel connection.
Resonant Energy Generator Array
Output and ControlPads
Power Processor
Summary
55T. Nishida, University of Florida
Summary
Piezoelectric transducers offer potential benefits for low power sensing and vibration/acoustic energy harvesting
Transducer may require for low power voltage/charge amplifier
Scaling down energy harvester decreases harvestable powerRequires arrays, low power active converter
56T. Nishida, University of Florida
Acknowledgements
Former and current studentsDr. Steve HorowitzDr. Anurag KasyapMr. Fei LiuMr. Robert Taylor
Collaborating facultyProf. Mark Sheplak, MAE UFProf. Lou Cattafesta, MAE UFProf. Khai D. T. Ngo, ECE UF/ VTech
SupportNASA LangleyNASA Glenn (NAG 3-2930 monitored by Timothy Smith)
57T. Nishida, University of Florida
Interdisciplinary Microsystems GroupInterdepartmental Research Group in College of Engineering
IMG initiated in 1998Mechanical and Aerospace Engineering
Mark Sheplak: (98) design, acoustics, fluid mechanicsLou Cattafesta: (99) flow control, acoustics, fluid mechanicsHugh Fan: (03) microfluidics, BioMEMS
Electrical and Computer EngineeringToshi Nishida: (88) noise, strained silicon, energy havestingHuikai Xie: (02) CMOS-MEMS, photonics, bio-imagingDavid Arnold: (05) micromagnetics, micro-power systems
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