Download pv-cells for optical power transmission - Fraunhofer

F R A U N H O F E R I N S T I T U T e F o R so l ar ener g Y syste m s I S E
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1 Power is transmitted in the form of
light generated by a monochromatic
light source.
2 At the receiver a photovoltaic cell
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PV-Cells for Optical
Power Transmission
converts the light back into electricity.
3 Electronic circuitry provides stable
Optical power transmission is an elegant
Photovoltaic cells can convert monochro-
power output at the required voltage.
way to replace copper wiring with fiber
matic light into electricity much more
optic cable for applications where con­
efficiently than the spectrum of the solar
ventional power supply is challenging
radiation. By tuning the photovoltaic cell’s
or even impossible due to:
semiconductor bandgap to the specific
wavelength of the light, thermalization and
n the risk of short circuits and sparks
transmission losses are minimized. In this
n the need for lightning protection
way, high conversion efficiencies of light
n electromagnetic interference
into electricity over 50% have been realized.
n the need for galvanic isolation
Fraunhofer Institute for
n high magnetic fields
Applications
n heavy weight of long distance cabling
The technology of optical power trans­
n susceptibility to corrosion and moisture
mission is suitable for a broad range of
Solar Energy Systems
applications, such as:
Heidenhofstrasse 2
Power can be transmitted in the form of
79110 Freiburg
light through an optical fiber or directly
n structural health monitoring systems
Germany
through air. A light source – namely a laser
Phone +49 761 4588-0
or an LED – generates monochromatic
n fuel gauges in aircraft wings
Fax +49 761 4588-9000
light. At the receiver a photovoltaic cell
n current transducers in high voltage www.ise.fraunhofer.de
converts the optical power back into
in wind turbines
power lines
electricity. Consequently copper wiring can
n implantable medical microsystems
Dr Henning Helmers
be avoided. In addition, the replacement of
n subscribers in optically powered Phone +49 761 4588-5094
copper wire by optical fiber enables com­
networks
[email protected]
bination of power and data transmission
n monitoring units in passive optical www.III-V.de
into a single fiber.
networks (PON)
What is your application?
March 2014
D
B
C
A
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Materials and Cell Concepts
Our Expertise
1 Components: Optical fiber with connec-
The bandgap of III-V semiconductors can
n photovoltaic cell development:
tors on both ends (A). Laser power converters
be well tuned by the composition of the
high efficiency due to excellent mounted on transistor outlines (TO header) (B).
material. At Fraunhofer ISE, III-V materials
material quality, advanced concepts Optical connector (C). Laser power converter
have been used in photovoltaic cells for
for increased voltage output, different
integrated into optical connector (D).
2 Automatic packaging of laser power conver-
many years. They were originally developed
materials for broad range of wave-
for highly efficient space and terrestrial
lengths, front grid optimization for ters on transistor outlines: thin wire bonding
concentrator solar cells. The spectrum of
high power operation, customized
for electrical contacts.
available materials covers a broad range
cell size and geometry
of wavelengths. In addition, advanced cell
concepts are developed for highest conver­
n characterization:
sion efficiencies, high power operation and
spectral quantum efficiency, current-
increased voltage output.
voltage characteristics at variable
intensity, monochromatic light Selected materials are available (with cutoff
illumination, electroluminescence, wavelength λc related to the bandgap at
photoluminescence
300 K):
Ga0.51In0.49P (λc=660 nm)
n automatic packaging:
GaAs (λc=870 nm)
mounting on transistor outline, vacuum Ga0.83In0.17As (λc=1050 nm)
soldering, wire bonding
Ga0.16In0.84As0.31P0.69 (λc=1100 nm)
Ga0.47In0.53As (λc=1680 nm)
n system integration:
GaSb (λc=1700 nm)
optical fiber coupling, connectors,
Ge (λc=1870 nm)
electronic circuitry, laser driver,
DC/DC converter
Increased voltage output of the photovol­
taic converter can be realized by application
n combination with data transmission
of advanced cell concepts:
n multi-junction cells:
n modeling:
vertical stacking of multiple cells interconnected by tunnel diodes
electrical, optical, thermal
n multi-segment cells (monolithic n reliability testing:
interconnected modules, MIMs):
lateral series interconnection of several
segments due to electrical separation on
semi-insulating wafer
degradation studies, accelerated ageing