WIRELESS POWER TRANSMISSION
THROUGH SPS (SOLAR POWER
Shitole Sanket S.
WIRELESS POWER TRANSMISSION
Nicola Tesla proposed the theory of wireless power
Transmission of energy from one place to another
place without using wires.
Three main systems used for WPT :
• Solar cells
WHY WPT ???
Low maintenance cost
Can be used for short range or long range
Reduction of losses during transmission and distribution
of electrical energy.
Need for grids, substations etc. are eliminated.
Noble alternative for electrical transmission.
TYPES OF WPT ...
There are mainly three major types of wireless energy transfer
Short range – INDUCTIVE COUPLING
Medium range – RESONANT COUPLING
Long range power transfer – ELECTROMAGNETIC
OVERVIEW OF SYSTEM DESIGN.....
It consists of :
I. Solar Panel.
II. Spacetenna ( antenna on satellite ).
III. Rectenna ( RECTifyin g anTENNA).
IV. Orbit selection Systematic view.
Set of solar photovoltaic modules electrically
connected and mounted on a supporting structure.
Photovoltaic module is a packaged , connected
assembly of solar cells.
Solar panels use photons(light energy) from sun to
generate electricity through photovoltaic effect.
Solar panels were first used in space in 1958.
SPACETENNA: (Antenna on Satellite)
Spacetenna is a triangular prism with a length of 800 m and sides
of 100 m.
The transmitting antenna on the horizontal under surface faces
the earth, and the other two sides of the prism carry solar arrays.
The faces of prism are embedded with photovoltaic cells .These
cells would convert solar energy into electricity, which in turn
power onboard , Microwave Generator.
The microwave thus produced travels through atmosphere &
collected by RECTENNAS on earth.
RECTENNA: (RECTIfying anTENNA)
mesh of an array of dipole antennas
connected to diodes converting the
radio frequency signal into DC
voltage, which is then converted into
regular AC electricity which is wired
to homes, factories etc.
It can be considered as a base station
of Geosynchronous satellite.
Microwaves of 2.45 GHz frequency is
used to transmit power from satellite
. A simple rectenna can be
constructed from a Schottky diode
placed between antenna dipoles as
shown in Fig.
ORBIT SELECTION SCHEMATIC VIEW
In LEO, a 11,00 Km
altitude equatorial orbit will
be used. This choice
minimizes the transmission
cost and the distance of
power transmission from
If it was in GEO ( that is
35,800 Km from the earth )
then the transmitting antenna
would have to be 40 times
larger than LEO one- or else
the receiving station would
have to be 40 times larger.
5,000 MW Receiving Station (Rectenna).This
Station is about a mile & a half long in US.
WHY TO USE SPS ?
More intense sunlight.
Unlimited energy resource.
Energy delivered anywhere in the world.
Zero fuel cost.
Zero co2 emission – environment safe.
Waste heat is radiated back into space.
No air or water pollution is created during the generation.
Concept is simpler than the other most power systems here
on the earth.
SPS doesn’t use up the valuable surface area on the
Solar radiation can be more efficiently collected.
Space gets full power 24 hours a day.
No effect of storms.
Eco- friendly and maintenance free energy resource.
Issues identified during DOE study :
Complexity – long years to complete.
Size- 6.5 miles long by 3.3 miles wide.
Transmitting antenna about 1.5 mile in diameter (1 km)
Cost – prototype would have cost $74 billion.
Interference with communication satellites
Would require a network of 100’s of satellite.
Heavy Launch cost
The large scale of space solar power require international
SPS is still more expensive than ground based solar
power & other energy sources. Yet even now, a small
SPS system could be economically justified to provide
unavailable emergency power for natural disaster
situations, urban blackouts & satellite power failures.
For WPT via SPS to become reality, we require:
Cheaper launch prices.
Involvement of private sector.
W.C. Brown, “Experiments Involving a Microwave
Beam to Power and Position a Helicopter”, IEEE
Transactions on Aerospace Electronic Systems. Vol.
AES-5, no. 5, pp 692-702
Satellite Power System Concept Development and
Evaluation Program July 1977 - August 1980. DOE/ET0034, February 1978.
Tesla, N., “The transmission of electric energy without
wires”, The thirteenth Anniversary