1. College Of Technology And Engineering
Mr. P.C. Bapna
JAI LAL MEENA
B.E. IVth Yr. (ECE)
Maharana Pratap University of Agriculture and
Inductive charging works on the basic principle in
which two power systems are placed very close to one
another. They need not to be exposed or connected to
each other. Each of these power systems contains an
electrical coil that stores electricity for the device’s use.
The coils’ proximity to each other results in the
generation of a low power electrical field that connects
4. This field allows the transfer of electricity
between the two systems. The two systems
share electricity until they both have exactly
the same amount of power. In inductive
charging, one of the devices, i.e., the sender,
is constantly powered so that it can send
power to the receiver continuously until the
receiver is fully charged.
6. Induction powers the charging mats that
wirelessly transfer energy to the devices and allows
them to be recharged by simply placing them on the
top of the mat. Inside the mat there is an inductive
coil through which the electricity runs and the
power is transferred to a second coil attached to the
device. Inductive charging uses an electromagnetic
field to transfer energy between two objects.
7. This is usually done with a charging station.
Energy is sent through inductive coupling to
an electrical device, which then can use that
energy to charge batteries.
There is a small gap between the two coils
employed in each of the sender and receiver
of the energy within the respective devices
due to which inductive charging is
considered a short-distance wireless energy
10. 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. The two induction coils in proximity
combine to form an electrical transformer.
The most familiar example of a Inductive coupling is a transformer.
In a transformer, a coil of wire with alternating current generates a time-
varying magnetic flux, which couples into an adjacent coil of wire and
generates a corresponding current on the secondary coil through magnetic
In a wireless inductive charging
system , the primary coil resides
in the charging device, and the
secondary coil is located
in the portable device. Therefore
it is necessary to use either an
air gap transformer, or a split-
core transformer with an air gap
between the two cores to
improve the efficiency.
When the secondary coil is brought
in close proximity to the primary coil,
the transformer is formed and energy
transfer occurs. This method of
wireless energy transfer can be fairly
efficient as the majority of the
magnetic flux resides in the core of the
transformer, and therefore losses due
to leakage fields are low except at the
air gap between the two cores.
Due to the need for a small air gap even in split core
transformers, the efficiency is lower than more traditional
transformer designs, and as the air gap increases the
effectiveness of the coupling is decreased significantly. For
these reasons this method is only useful for energy transfer
over short distances.
13. Power losses occur because the changing magnetic field
will also induce currents in the iron core. These induced
currents are known as eddy currents. Eddy currents will
generate heat and reduce the transformer's efficiency. In
order to reduce the formation of eddy currents, a laminated
core is used.
Current flowing through the primary and secondary coils
will generate heat. Low resistance copper wires is used to
reduce this effect.
LOSSES IN TRANSFORMER
14. The core is magnetised and demagnetised alternately
when AC current flows through the primary coil.
Energy is lost during this process. This is known as
Hysterisis. This effect is reduced by using a soft iron
There may be a leakage of magnetic flux in the
primary coil. A special core design is used in a
transformer to ensure that all the primary flux is linked
with the secondary coil .
15. Charger output:Up to 850mA and up to 8.5 Volts.
Maximum power: 20W+.
Range: 1cm or less.
Generally available in form of Charging pads.
18. Power Mat 3X is a sleek, slim three position wireless charging
mat for home and office. A magnetic attraction between every
receiver and each access point on every Mat assures that
alignment is precise and the most efficient charging occurs.
Communication between the Mat and the Receiver allows the
mat to deliver an exact amount of power for the proper length
of time so that the transfer of power is safe and efficient and no
energy is wasted. When the device reaches full charge, power is
shut off to that device, which avoids overcharging of the device's
battery as well as saves energy. Once full power is achieved and
the Auto Shut Off has occurred to save energy, the system will
monitor the status of the battery in the device. If the battery is
used, the system will again initiate charging and return the
battery to a full charge.
20. Time varying magnetic fields can be used to transfer power across
the skin to drive implantable biomedical devices without the use
of percutaneous wires.
This system consists of two coils, one internal and one external
that transmit power via magnetic force from an external battery
across the skin without piercing the surface.
The internal coil receives the power and sends it to the internal
battery and controller device.
Creation of a shock free environment .
Reduction in power theft.
A solution to reduce e-waste.
Efficiency not affected by room geometry.
Can charge multiple devices.
Can deliver power through walls.
No Need of transmission lines.
Wireless chargers are cost effective,
adaptable, portable and stylish.
Possibility of harmful radiation.
Doesn’t have a very large range.
Higher Initial Cost.
Increase in distance decreases
increased resistive heating.
Wireless charging has huge potential. This is why people
have been working on it for well over a century. If we could
move power without wires we’d be able to re-think not just
consumer electronics but the infrastructure used by the
entire human race.
Transmission without wires become a reality.
In future, world will be wireless.
Future improvements in wireless power technology offer
world changing implications.