raghavendra bhovi
Post on 17-Jul-2015
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Presented by
Raghavendra1bg12ee404
Department of Electrical and electronics Engineering
BNM Institute of Technology, bangalore
What is wireless power transmission(WPT)?
Why is WPT?
History of WPT
Types of WPT Techniques to transfer energy wirelessly
Advantages and disadvantages
Applications
Conclusion
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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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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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ReliableEfficientFastLow maintenance costCan be used for short-range or
long-range.
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Nikola Tesla in late 1890s
Pioneer of induction techniques
His vision for “World Wireless System”
The 187 feet tall tower to broadcast energy
All people can have access to free energy
Due to shortage of funds, tower did not operate
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Near-field techniques Inductive Coupling
Resonant Inductive Coupling
Air Ionization
Far-field techniquesMicrowave Power Transmission (MPT)
LASER power transmission
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Primary and secondary coils are not connected with wires.
Energy transfer is due to Mutual Induction
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Transformer is also an example
Energy transfer devices are usually air-cored
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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Combination of inductive coupling and resonance
Resonance makes two objects interact very strongly
Inductance induces current
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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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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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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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Distance constraint
Field strengths have to be under safety levels
Initial cost is high
In RIC, tuning is difficult
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Electric automobile charging
Consumer electronics
Industrial purposes
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It permits long range of energy transfer
Aim at high power transfer
LASER or microwave
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Transfer high power through outer atmosphere without the need of wire
Efficiency is high at receiver and transmitter end
Attenuation is less
Used to transmit energy point to point
Also known as laser power beaming
Simple receiver Photovoltaic cell
Cost-efficient
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To provide energy to earths increasing energy need
Solar energy is captured using photocells
Each SPS may have 400 million photocells
Transmitted to earth in the form of microwaves/LASER
Using rectenna/photovoltaic cell, the energy is converted to electrical energy
Receives power on earth by using rectennas
Efficiency exceeds 95% if microwave is used.
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Stands for rectifying antenna
Consists of mesh of dipoles and diodes
Converts microwave to its DC equivalent
Usually multi-element phased array
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Rectenna in US receives 5000MW of power from SPS
It is about one and a half mile long
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Efficient
Easy
Low maintenance cost
More effective when the transmitting and receiving points are along a line-of-sight
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Initial cost is high
When LASERs are used, Absorption loss is high
When microwaves are used, interference may arise
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Far-field energy transfer Solar Power Satellites
Laser power beaming is used in military weapon aerospace
Spacecraft , satellites , etc
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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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