Wireless Energy Transfer

Wireless energy transfer

Chandana.ks & HarishE & c department

Govt.SKSJTI, Bangaluru-01

Introduction•Wireless energy transfer or wireless power transmission [WiTricity]•where we use this?•Efficiency concerns.

Nikola Tesla- Father of Wireless

1856-1943 Innovations:

– Alternating current

– Wireless power transmission experiments at Wardenclyffe

Wardenclyffe 1899

– Able to light lamps over 25 miles away without using wires

– High frequency current, of a Tesla coil, could light lamps filled with gas (like neon)

The forgotten invention is reborn in 2007

*2007: A physics research group, led by Prof. Marin Soljačić, at MIT2009: Texas Instruments releases the first device •2010: Haier Group debuts the world's first completely wireless LCD television at CES based on Prof. Marin Soljacic's follow-up research on wireless energy transfer and Wireless Home Digital Interface (WHDI).

TECHNIQUES OF ENERGY TRANSFER

1. Near field techniques:

A. Induction technique ( Inductive coupling)

B. Electrodynamic induction technique (resonant energy transfer)

C. Electrostatic induction technique (Capacitive coupling)

2. Far field techniques: A. Radio and microwave (Microwave power

transmission)technique

B. Laser

1. Near field techniques:

Near field energy itself is non radiative, but some radiative losses will occur. In addition there are usually resistive losses.

Near field transfer is usually magnetic (inductive), but electric (capacitive) energy transfer can also occur.

A. Induction technique ( Inductive coupling):

Working Principle- mutual induction.

EX: Battery chargers for mobile phone, transformers on the street, Induction cookers and many electric toothbrushes are also powered by this technique.

The main drawback to induction, however, is the short range. The receiver must be very close to the transmitter or induction unit in order to inductively couple with it.

B.Electrodynamic induction technique (resonant energy transfer):

working principle- resonant coupling

Ex: powering contactless smartcards, and systems exist to power and recharge laptops and cell phones

C. Electrostatic induction technique (Capacitive coupling)

working Principle- capacitive couplingEx: Tesla’s wireless bulb

2.Far field techniques:

Means for long conductors of electricity forming part of an electric circuit and electrically connecting said ionized beam to an electric circuit.

Far field methods achieve longer ranges, often multiple kilometer ranges.

The maximum directivity for antennas is physically limited by diffraction.

A. Radio and microwave (Microwave power transmission)technique

Working principle- microwave transmission A blockdiagram of the demonstration components is shown. The primary components include a microwave source, a transmitting antenna, and a receiving rectenna.Diagram showing the transmitting & receiving circuit For the transmission & reception of electric power by wireless

Two optical forms of wireless antennae formed of search light beam- ionised atmospheric streams

.

5,000 MW Receiving Station (Rectenna). This station is about a mile and a half long.

Drawbacks-Power beaming by microwaves has the difficulty that for most space applications the required aperture sizes are very large due to diffraction limiting antenna directionality.For earthbound applications a large area 10 km diameter receiving array allows large total power levels to be used while operating at the low power density suggested for human electromagnetic exposure safety.

A human safe power density of 1 mW/cm2 distributed across a 10 km diameter area corresponds to 750 megawatts total power level. This is the power level found in many modern electric power plants.

B. Laser

Working principle- power beaming

Because the power is beamed at a receiver that can convert it to usable electrical energy.

CONTINUED….Collimated monochromatic wavefront propagationAbility to operate with zero radio-frequency interferenceno authentication before transferring energy.the laser. power can only drive the motion of an arm and fingers. For robots.laser-based transfer of energy especially for space and lunar missions.

Advantageseliminate the need for an inefficient, costly, and capital intensive grid of cables, towers, and substations.can be economically transmitted without wires to any terrestrial distanceTransmission Integrity and Low Loss

Drawbacks Biological Impact:- frequency is very

biologically compatible. Economic Impact:- The concept looks to be

costly initially. Conversion to light, such as with a laser, is

moderately inefficient . With 40%to50% efficiency.

Atmospheric absorption causes losses

How safe is wirticity?WiTricity coupling resonance' is safe for humans. If

guidelines from ICNIRP are followed.But If radio waves & fluctuating magnetic field

transmit heat to our cells, they can damage tissue over a long period of time. in the same way that radiation from cellphones does.

the magnetic fields tend to interact very weakly with the biological tissues of the body provided the exposure is below the thresholds .

The matter is still open to debateSpeaking of kids, wireless energy could help to make

the household a safer place

Future of witricity

Imagine electric cars, laptops, digital camera's getting self charged! Wow!

health issues currently flared away to produce electricity

locally and then beam it by satellite to other countries' receivers attached to local power grids.

However, the future certainly seems bright and interesting! So, think positive and hope for the best!

To conclude The transmission of power without wires is not a

theory or a mere possibility, it is now a reality.have tremendous merits like high transmission

integrity and Low Loss (90 – 97% efficient)can be transmitted to any where in the globe eliminate the need for an inefficient, costly, and

capital intensive grid of cables, towers, and substations

It has negligible demerits like reactive power which was found insignificant and biologically compatible.

Many countries will benefit from this service.

From where did we get this idea???Thomas F. Valone, “ Tesla’s Wireless Energy... For the

21stCentury!!! One Step Beyond Direct TV!!!” Extra Ordinary Technology, 1, no. 4, Oct / Nov / Dec 2003.

Joe T. Howell, et. al , “Advanced receiver / converter experiments for laser wireless power transmission”5th. Wireless transmission conference, pp 1-8, Garanda, Spain,2004.

van Vlaenderen, Koen J., "A Generalization of Classical Electrodynamics for the Prediction of Scalar Field Effects," Institute for Basic Research, 2008

The Transmission of Electrical Energy Without Wires," ''Electrical World'', March 5, 1904". 21st Century Books. 1904-03-05. Retrieved 2009-06-04.

For any further clarificationsChandana.ks2010@gmail.com Hareesh Ph:9480081303

Thanking you