INTRODUCTION
• In wireless charging the current coming from the wall power outlet moves
through the wire in the wireless charger, creating a magnetic field. The
magnetic field creates a current in the coil inside the device. This coil is
connected to the battery and the current charges the battery. The two
induction coils in proximity combine to form an electrical transformer.
• Induction chargers typically use an induction coil to create an alternating
electromagnetic field from within a charging base station, and a second
induction coil in the portable device takes power from the electromagnetic
field and converts it back into electrical current to charge the battery.
Methods of Wireless Charging
There are three types of wireless charging :-
• Resonance Charging
• Inductive Charging
• Radio Charging
Resonance Charging :
• It uses phenomenon of “RESONANCE”, that causes an object
to vibrate when energy of certain frequency is applied.
• Two copper coils are used one attached to transmitter &
another to receiver.
• Both coils are tuned to same electromagnetic frequency.
• These coils when placed close to one another power is
transferred.
Examples:-• Electric cars
• Robots
• Vacuum Cleaners
• Laptop computers &
Other items that require large amounts of power.
Inductive Charging :
• Inductive charging is one kind of short distance wireless charging.
• This method works on the principle of
“ELECTROMAGNETIC INDUCTION” where the charger device
will create an E.M field with alternating polarity using a coil of
insulated copper wire & a similar coil will be placed inside the
mobile device which will convert E.M field back to electric current
there by charging the battery.
Examples:-• MP3 players.
• Personal Digital Assistants (PDA’s).
• Electric toothbrushes.
• Waterproof Vibrating Razors. & Other mid-sized items.
Radio Charging :
• This method is on the basis that Radio Waves are widely in use to transmit and receive cellular telephone, television, radio and Wi-Fi.
• A Radio wave once transmitted, propagates in all directions until it reaches an antenna tuned to proper frequency to receive it.
• A transmitter plugged in to a socket, generates radio waves, when the receiver attached to the device is set to the same frequency as the transmitter, it will charge the device’s battery
Examples:-
• Watches.
• Hearing aids.
• Medical implants.
• Cell phones.
• Wireless keyboards & Other charging devices with small batteries and low power requirements.
NEED OF WIRELESS CHARGING
To make the recharging of the mobile phones independent of
their manufacturer and battery make.
A new proposal has been made so as to make the recharging
of the mobile phones is done automatically as you talk in your
mobile phone.
The microwave signal is transmitted from the transmitter along
with the message signal using special kind of antennas called
slotted wave guide antenna at a frequency is 2.45 GHz.
Advantages of Wireless Charging
The need of different types of chargers by different
manufacturers is totally eliminated
Lower risk of ELECTRICAL SHOCK or shorting.
Convenience
Wireless energy transfer can potentially recharge the mobile
phones without chords.
Disadvantages of Wireless Charging
The transmitter and receiver also should be very powerful
devices as the distance increases.
Slower Charging.
Wireless transmission of the energy causes some drastic effects
to human body, because of its radiation.
More costly.
Practical possibilities are not yet applicable as there is no much
advancement in this field.
• In the car: As demonstrated by Fulton Innovation at CES 2011, we may also begin seeing electric-powered vehicles get
powered up via a manhole-sized charging pad.
Other Applications:
• Inductive Coupling-RFID.
• In-Vehicle Charging.
• Radio Charging.
• Ultra Wideband.
WIRELESS CHARGING STANDARDS
• Qi is a set of guidelines for inductive charging units. Right
now it is a default standard.
• It's rounded up 84 manufacturers, semiconductors, and telecom
providers under its wing so far, a number which no other
organizations have come close to matching.
Current Players in the Wireless Charging
• DELL- Dell has started giving the option of having wireless chargers in
there customization option to the customers.
• Palm Inc- This smart phone company announced in 2009 to launch touch
stone models of phones with wireless charger as its standard accessory.
• Hughes Electronics- This Company in collaboration with General motors
introduced a battery operated car with the option of recharging it wireless.
The car is named General Motors EV1 electric car.
• Evatran Company- A subsidiary of MTC Transformers
began development of ‘plug less power’ in 2009. This is based
on inductive charging system which will power electric car
through wireless recharging technology.
• Toshiba- They released a wireless powered television which
was first in the world to have a powering mechanism of that
kind
• Wireless Power Consortium- An alliance of 20 firms had formed this
group to device open source standard for wireless charging technology.
Some bug tickets include Philips, Sanyo, Nokia, Texas Instruments,
research in Motion, Duracell, and Energizer etc.Their draft version is ready
as of July 2010. Some companies like Samsung electronics and Ericson are
associates of this group who will contribute standards to be part of this
alliance.
• IAV GmbH-This German Company is working on chargers which can be
implemented in the road which would allow the car to be charged as it
runs along the road surface.
Conclusion
A novel method of using the power of the microwave to charge
the mobile phones without the use of wired chargers.
This method provides great advantage to the mobile phone
users to carry their phones anywhere even if the place is devoid
of facilities for charging.
FUTURE SCOPE
The wireless charging can even be done using the data exchange as now
only its only been implemented for voice calls.
With the advent of nanotechnology and MEMS the size of these rectennas
can be brought down to molecular level. It has been theorized that similar
devices, scaled down to the proportions used in nanotechnology, could be
used to convert light into electricity at much greater efficiencies than what
is currently possible with solar cells. This type of device is called an
optical rectenna.
References
• www.wikipedia.com
• www.Howdostuffwork.com
• www.WhatIs.com
• www.google.com
• www.1000projects.com
• www.ieee.com
• www.chetanasprojects.com
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