wi tricity
TRANSCRIPT
WiTricityWiTricity
Wireless Power Wireless Power TransmissionTransmission
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What is WPT?What is WPT?The transmission of energy from
one place to another without using wires
Conventional energy transfer is using wires
But, the wireless transmission is made possible by using various technologies
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HistoryHistory
Nikola Tesla in late 1890sPioneer of induction techniquesHis vision for “World Wireless System”The 187 feet tall tower to broadcast
energyAll people can have access to free energyDue to shortage of funds, tower did not
operate
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ORIGINAL WORK OF TESLAORIGINAL WORK OF TESLA
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There’s something new coming up to play with ‘Wireless Electricity’.
In the first successful trial of its kind, the team was able to illuminate a 60-watt light bulb 7ft away .
The team from Massachusetts Institute of Technology, who call their invention ‘WiTricity‘.
What Is Inductive Coupling?InductiveCoupling is a method for
short range wireless energy transfer. Its range can vary, but it’s often
very short.
Short Range Wireless Energy Short Range Wireless Energy Transmission: Inductive Transmission: Inductive CouplingCoupling
Inductive coupling Inductive coupling Primary and secondary coils are
not connected with wires.Energy transfer is due to Mutual
Induction
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How does Inductive Coupling How does Inductive Coupling Work?Work?
Inductive coupling works on the principles of electromagnetism:When a current (electricity) passes through a wire, it generates a magnetic field perpendicular to the wire.When a wire is in proximity to a magnetic field, it generates a current in that wire.
Magnetic fields decay quickly , making inductive coupling effective only at very short ranges.
What Is Resonant Induction?
A group of engineers at MIT came up with the idea to use resonant induction to transmit power wirelessly. They deemed their result “WiTricity” (like Wi-Fi) . WiTricity can transmit electricity wirelessly at 40% efficiency to about 7 feet.
Medium Range Wireless Medium Range Wireless Energy Transmission: Energy Transmission: Resonant InductionResonant Induction
Resonance Inductive Resonance Inductive Coupling(RIC)Coupling(RIC)Combination of inductive
coupling and resonanceResonance makes two objects
interact very stronglyInductance induces current
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How resonance in RIC?How resonance in RIC?Coil provides the inductanceCapacitor is connected parallel to
the coilEnergy will be shifting back and
forth between magnetic field surrounding the coil and electric field around the capacitor
Radiation loss will be negligible
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Block diagram of RICBlock diagram of RIC
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An exampleAn example
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WiTricity (contd…)WiTricity (contd…)
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DisadvantagesDisadvantagesDistance constraintField strengths have to be under
safety levelsInitial cost is highIn RIC, tuning is difficultHigh frequency signals must be
the supplyAir ionization technique is not
feasible04/11/23 Wireless Power Transmission 17
Microwave Power Microwave Power Transfer(MPT)Transfer(MPT)Transfers high power from one
place to another. Two places being in line of sight usually
Steps:◦Electrical energy to microwave energy◦Capturing microwaves using rectenna◦Microwave energy to electrical energy
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MP T (contd…)MP T (contd…)AC can not be directly converted
to microwave energyAC is converted to DC firstDC is converted to microwaves
using magnetronTransmitted waves are received
at rectenna which rectifies, gives DC as the output
DC is converted back to AC
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Solar Power Satellites Solar Power Satellites (SPS)(SPS)
To provide energy to earth’s increasing energy need
To efficiently make use of renewable energy i.e., solar energy
SPS are placed in geostationary orbits
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SPS (contd…)SPS (contd…)Solar energy is captured using
photocellsEach SPS may have 400 million
photocellsTransmitted to earth in the form of
microwaves/LASERUsing rectenna/photovoltaic cell, the
energy is converted to electrical energyEfficiency exceeds 95% if microwave is
used.
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RectennaRectennaStands for rectifying antennaConsists of mesh of dipoles and
diodesConverts microwave to its DC
equivalentUsually multi-element phased
array
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Rectenna in USRectenna in USRectenna in US receives 5000MW
of power from SPSIt is about one and a half mile
long
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Other projectsOther projectsAlaska’21
Grand BassinHawaii
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MIT's WiTricity is only 40 to 45% efficient and they have to be twice as efficient to compete with the traditional chemical batteries.
Aim is to get a robotic vacuum or a laptop working, charging devices placed anywhere in the room
The researchers have said that in another five years time, they will come up with a WiTricity system for commercial use.
What's the Future of WiTricity? What's the Future of WiTricity?
ConclusionConclusionTransmission without wires- a realityEfficientLow maintenance cost. But, high initial
costBetter than conventional wired
transferEnergy crisis can be decreasedLow loss In near future, world will be
completely wireless
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