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
History of Wireless Power In 1899, Sir Nikola Tesla Proposed a method of Wireless Power Transmission. Nikola Tesla – The Genius He enlighted 200 lamps at the distance of 40 km, Wirelessly ! The efficient midrange powertransfer concept is Witricity. In thismodel source and load are inMagnetic resonance so there is nopower loss.
Research at MIT * Prof. Soljacic – Another Genius MIT-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 fromload.
Electric bulb lightened even when a barrier waskept 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 electromagneticresonators coupled mostly throughtheir 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 MicrowavePower 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 InductiveCoupling(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
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 issafe 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