ELECTRICITY THROUGH WIRELESS TRANSMISSION-WITRICITY
by
Apoorva
Introduction
In our present electricity generation system we waste more than half of its resources. Especially transmission and distribution losses are main concern of the present power technology.
The transmission and distribution system causes a loss of 26% to 30% of energy generated.
The transmission of power without wires is one of the alternative for electricity transmission
History of Wireless Power
In 1899, Sir Nikola Tesla Proposed a method of Wireless Power Transmission.
The efficient midrange power transfer concept is Witricity. In this model source and load are in Magnetic resonance so there is no power loss.
Nikola Tesla – The GeniusHe enlighted 200 lamps at the distance of 40 km, Wirelessly !
Research at MIT
* Prof. Soljacic – Another GeniusMIT-IBM Collaboration
* He did succeed to redesign Tesla’s experiment in safer way.* They had lit up a 60W bulb with a power source at a distance of 7 feet(over 2m) with no wires
The forgotten invention is reborn in 2007RESONANCE COUPLING
A group of engineers at MIT came up with the idea to use resonant induction to transmit power wirelessly.
“Resonance", a phenomenon that causes an object to vibrate when energy of a certain frequency is applied.
Experiment demonstrated at MIT.A 60W light bulb lit from source at a distance of 2m from load.
Electric bulb lightened even when a barrier was kept in between.
Need of Witricity:
* Cell phones, i pods, laptop computers are capable of re-charging themselves without ever being plugged in.
What is WiTricity ?
definition is : * “Transmission of energy through the air”.* A system of two electromagnetic resonators coupled mostly through their magnetic fields.
* Cables are going to replaced by WiTricity.
* Efficient power transfer
Types and Technologies
Near-field techniques Inductive Coupling Resonant Inductive Coupling Air Ionization
Far-field techniques Microwave Power Transmission (MPT) LASER power transmission
Inductive coupling
Primary and secondary coils are not connected with wires.
Energy transfer is due to Mutual Induction
Cont…
Energy transfer devices are usually air-cored
Transformer is an example Wireless Charging Pad(WCP),electric
brushes are some examples The charging pad (primary coil) and the
device(secondary coil) have to be kept very near to each other
Resonance Inductive Coupling(RIC)
* Same concept as Inductive coupling just that the coils operate at resonant frequency leading to efficient transfer of energy over a larger distance.
* Interacts weakly with extraneous off resonant objects.
* Radiation loss will be negligible
Resonant Inductive Coupling
Air Ionization
Toughest technique under near-field energy transfer techniques
Air ionizes only when there is a high field Needed field is 2.11MV/m Natural example: Lightening Not feasible for practical implementation.
Far-field energy transfer
Microwave Power Transfer(MPT) Transfers high power from one place to another. Steps:
Electrical energy to microwave energy Capturing microwaves using rectenna Microwave energy to electrical energy
AC can not be directly converted to microwave energy
AC is converted to DC first DC is converted to microwaves using magnetron Transmitted waves are received at rectenna which
rectifies, gives DC as the output DC is converted back to AC
LASER transmission
LASER is highly directional, coherent Not dispersed for very long But, gets attenuated when it propagates
through atmosphere Simple receiver
Photovoltaic cell Cost-efficient
Applications
Direct Wireless Power No device needs wires For TVs, toasters or any form of
Immobile devices
Automatic Wireless Charging Device with rechargeable
batteries charges itself
For any form of mobile device
Some more Applications…
* Consumer electronics. *Industrial
would be free of heavy installation of wires and devoid of any hazardous electric shock incidents.
*Transportation Could charge an electric car or automobile.
Wireless power transmission is safe
Human beings or other objects placed between the transmitter and receiver do not hinder the transmission of power.
magnetic fields tend to interact very weakly with the biological tissues of the body, and so are not prone to cause any damage to any living beings.
Advantages
Efficient and reliable power. Creation of a shock free environment devoid of any
chances of power thefts. Provides solution to the ever increasing demand for
power. A solution to reduce e-waste- a more safe environment. A more cost effective methodology for getting
electricity to your houses which includes paying less for use of power.
Not affected by the day and night cycle, leads to lesser limitations on power harvesting.
Disadvantages.
For short and mid range transfer system has to be set at the right frequency or there would be no power transfer.
For long range the installation cost is high.
CONCLUSION
Transmission without wires- a reality Efficient Low maintenance cost. But, high
initial cost Better than conventional wired
transfer Energy crisis can be decreased Low loss In near future, world will be
completely wireless
Thank you