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Yang Bai1, Carl Meggs
1, Tim W Button
1,2
1 Metallurgy & Materials, University of Birmingham, Birmingham, United Kingdom 2 Central European Institute of Technology, Brno, Czech Republic
Introduction Having experienced more than 20 years’ research, Piezoelectric Energy Harvesting has shown to be a promising technology, and is predicted to approach commercialisation in several years. In order to evaluate the feasibility and explore potential applications, this poster presents the charging behaviour of vibration and wind energy harvesters based on integrated free-standing thick-film piezoelectric cantilevers, in which individual elements have been investigated and developed by the authors at earlier stages of the project.
Vibration Harvester - Individual Charging 1000 μF Capacitor - Individual
Contacts: [email protected] (Y. Bai); [email protected] (C.Meggs); [email protected] (T. W. Button)
Vibration Harvester - Array Charging 1000 μF Capacitor - Array
Figure 1. Proposed individual energy harvester with free-standing thick-film structure: (a) schematic of the construction; (b) the fabricated harvester.
~13 mm
~250 μm
0.1 g
Piezoelectric Thick-film
Piezoelectric Thick-film
Base (fixed end) Free end
Silver Lead Tip Mass
(a)
1 cm
(b)
Figure 2. (a) The schematic of the connection method (b) the picture of an array.
Table 1. Summary of the dimensions, tip masses and frequencies of the array.
Wind Harvester Based on Piezoelectrics
Figure 3. Pictures of wind harvester incorporating piezoelectrics: (a) front-side; (b) back-side
Free-spinning fan
(a) (b)
Diode bridge rectifiers
Individual harvesters
Magnets
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0 25 50 75 100
Cap
acit
or
Vo
ltag
e (
V)
Time (min)
107Hz, 0.3g107Hz, 0.5g
2.1
1.3 V
olt
age
(V)
Time (ms) 20 80
3.6
2.8 Time (ms) 20 80
Vo
ltag
e (V
)
g≈9.8m/s2
107Hz, 0.3g
107Hz, 0.5g
Figure 4. Instantaneous output voltage and charging response of an individual harvester.
Test Sieve Shaker
0.0
0.5
1.0
1.5
2.0
100 105 110 115 120 125 130
0.5g
0.0
0.1
0.2
0.3
0.4
0 5 10 15 20
Summary • Vibration harvesters have been able to charge a 1000 μF capacitor,
under both harmonic and machinery vibration. • Proposed structure has also been proved feasible to incorporate to
a wind system, showing comparable output voltage and charging rate to those of the vibration systems.
Charging 1000 μF Capacitor - Wind
Figure 6. Instantaneous output voltage and charging response of a wind harvester in a series of four consecutive tests.
Array
Nano-voltmeter
Capacitor
Time (min)
Uc (V
)
Frequency (Hz)
Uo
(V)
Figure 5. (a) Test configuration, (b) harmonic output and (c) charging response of an array mounted on a sieve shaker.
Uo: RMS output voltage of the harvester
Uc: Capacitor voltage
(a) (b)
(c)
Laboratory fan used as wind source
4.0
2.8
Vo
ltag
e (V
)
20 80 Time (ms)
1 cm
1 cm
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
0 5 10 15 20
Cap
acit
or
Vo
ltag
e (
V)
Test 1
Test 2
Test 3
Test 4
Time (min)
Consecutive