1Wireless Energy Transmission

NEOTIA INSTITUTE OF TECHNOLOGY MANAGEMENT AND SCIENCEDEPARTMENT OF ELECTRONICS AND

COMMUNICATION

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Contents

• WHAT IS WIRELESS POWER TRANSMISSION(WPT)?

• WHY IS WPT?• HISTORY OF WPT• TYPES OF WPT

Techniques to transfer energy wirelessly• Applications

• ADVANTAGES AND DISADVANTAGES

• CONCLUSION• REFERENCES

3What is Wireless Energy Transmission?

The transmission of energy from one place to another without using wires

Energy transfer is using wires

But, the wireless transmission is made possible by using various technologies

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Why not wires?

As per studies, most electrical energy transfer is through wires.

Most of the energy loss is during transmission

• On an average, more than 30%

• In India, it exceeds 40%

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Why Wireless Energy Transmission?

Reliable

Efficient

Fast

Low maintenance cost

Can be used for short-range or long-range.

6Nikola Tesla’s Demonstration

In 1891, Nikola Tesla gave a lecture for the members of the American Institute of Electrical Engineers in New York City.

Using glass discharge tubes for his experiment.

The tubes were not connected to any wires.

He went on to speculate how one might increase the scale of this effect to transmit wireless power.

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Tesla’s Other Experiments

Experiment with Static electricity

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Tesla’s Power-Tower

Diagram of Power-TowerTesla’s House

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Energy Coupling

The transfer of energyMagnetic couplingInductive coupling

Simplest Wireless Energy coupling

is a transformer

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Air Ionization Experiment

In 1899 Sir NICOLA TESLA and HEINRICH HERTZ powered a fluorescent lamp keeping it 25 miles away from source without using wire.

A high potential transmitter transmits an “electromotive impulse” through the ionized path to the upper atmosphere where it ionizes the air, and this air between the transmitter and receiver would conduct like a neon tube .

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Wireless Power System

12Techniques for wireless Transmission of Power

NEAR-FIELD TECHNIQUES

• INDUCTIVE COUPLING• RESONANT INDUCTIVE

COUPLING

FAR-FIELD TECHNIQUES

• MICROWAVE POWER TRANSMISSION(MPT)

• LASER POWER TRANSMISSION(LPT)

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Inductive Coupling Method

• Primary and secondary coils are not connected with wires.

• Energy transfer is due to Mutual Induction

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Inductive Coupling(Contd..)

Transformer is also an example Energy transfer devices are usually through air. Wireless Charging Pad(WCP),electric brushes are some examples On a WCP, the devices are to be kept, battery will be automatically

charged.

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Resonant Inductive Coupling

• Combination of inductive coupling and resonance

• Resonance makes two objects interact very strongly inductance induces

current

• Inductance induces current

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Resonant Inductive Coupling(Contd…)

• Coil provides the inductance• Capacitor is connected parallel to

the coil• Energy 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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Circuit Diagram

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Microwave Transmission Method

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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Microwave Transmission Concept

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Microwave Power Transmission (Contd….)

• 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

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Rectenna

It is a rectifying antenna

Microwaves are received with about 95% efficiency

Converts microwave energy into DC

Consists of mesh of dipole antennas

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LASER Transmission Method

LASER is highly directional, coherent

Not dispersed for very long

But, gets attenuated when it propagates through atmosphere

Simple receiver Photovoltaic cell

Cost-efficient

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Laser (Contd…)

In the case of electromagnetic radiation closer to visible region of spectrum (10s of microns(um) to 10s of nm), power can be transmitted by converting electricity into a laser beam that is then pointed at a solar cell receiver. This mechanism is generally known as "power beaming" because the power is beamed at a receiver that can convert it to usable electrical energy.

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Laser Method Block diagram

Transformer

Receiver

Current Source

LaserOptical Fiber

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Wireless Electricity-

WiTricity

• BASED ON RIC

• LED BY MIT’S MARIN SOLJAČIĆ

• ENERGY TRANSFER WIRELESSLY FOR A DISTANCE JUST MORE THAN 2M.

• COILS WERE IN HELICAL SHAPE

• NO CAPACITOR WAS USED

• EFFICIENCY ACHIEVED WAS AROUND 40%

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WiTricity contd…

WiTricity experimented to power incandescent bulb kept few meters away.

WiTricity experimented to power incandescent bulb kept few meters away with a obstacle.

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WiTricity Now

No more helical coils

Companies like Intel are also working on devices that make use of RIC

Researches for decreasing the field strength

Researches to increase the range

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Applications

Wireless Parking charger Wireless Electronic charger

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WiTricity Corporation products

WiTricity Corporation plans to operate each and every household electronic gadgets with wireless energy control techniques

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Air Ionisation

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

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RIC vs Inductive Coupling

RIC is highly efficient

RIC has much greater range than inductive coupling

RIC is directional when compared to inductive coupling

RIC can be one-to-many. But usually inductive coupling is one-to-one

Devices using RIC technique are highly portable

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Advantages of Near-Field Techniques

No wires No e-waste Need for battery is eliminated Efficient energy transfer using RIC Harmless, if field strengths under safety levels Maintenance cost is less

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Disadvantage

Distance constraint Field strengths have to be under safety levels Initial cost is high In RIC, tuning is difficult High frequency signals must be the supply Air ionization technique is not feasible

34Laser vs Microwave Power Transmission

When LASER is used, the antenna sizes can be much smaller

Microwaves can face interference (two frequencies can be used for WPT are 2.45GHz and 5.4GHz)

LASER has high attenuation loss and also it gets diffracted by atmospheric particles easily

35Advantages of far-field energy transfer

Efficient

Easy

Need for grids, substations etc are eliminated

Low maintenance cost

More effective when the transmitting and receiving points are along a line-of-sight

Can reach the places which are remote

36Disadvantages of a far-field energy transfer

Radiative Needs line-of-sight Initial cost is high When LASERs are used,

conversion is inefficient Absorption loss is high

When microwaves are used, interference may arise FRIED BIRD effect

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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

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References

S. Sheik Mohammed, K. Ramasamy, T. Shanmuganantham,” Wireless power transmission – a next generation power transmission system”, International Journal of Computer Applications (0975 – 8887) (Volume 1 – No. 13)

Peter Vaessen,” Wireless Power Transmission”, Leonardo Energy, September 2009 C.C. Leung, T.P. Chan, K.C. Lit, K.W. Tam and Lee Yi Chow, “Wireless Power Transmission

and Charging Pad” David Schneider, “Electrons unplugged”, IEEE Spectrum, May 2010 Shahrzad Jalali Mazlouman, Alireza Mahanfar, Bozena Kaminska, “Mid-range Wireless

Energy Transfer Using Inductive Resonance for Wireless Sensors” Chunbo Zhu, Kai Liu, Chunlai Yu, Rui Ma, Hexiao Cheng, “Simulation and Experimental

Analysis on Wireless Energy Transfer Based on Magnetic Resonances”, IEEE Vehicle Power and Propulsion Conference (VPPC), September 3-5, 2008

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References(contd…)

André Kurs, Aristeidis Karalis, Robert Moffatt, J. D. Joannopoulos, Peter Fisher and Marin Soljačić, “Wireless Power Transfer via Strongly Coupled Magnetic Resonances”, Science, June 2007

T. R. Robinson, T. K. Yeoman and R. S. Dhillon, “Environmental impact of high power density microwave beams on different atmospheric layers”,

White Paper on Solar Power Satellite (SPS) Systems, URSI, September 2006 Richard M. Dickinson, and Jerry Grey, “Lasers for Wireless Power

Transmission” S.S. Ahmed, T.W. Yeong and H.B. Ahmad, “Wireless power transmission and

its annexure to the grid system”

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Thank You!