18-01-2013, 11:39 AM
WIRELESS POWER TRANSMISSION
WIRELESS POWER.docx (Size: 165.81 KB / Downloads: 45)
ABSTRACT:
Transmission or distribution of 5o Hz or 60 Hz electrical energy from the generating point to the consumers’ end without any physical wire has yet to as a familiar and viable technology.
This paper focuses on the past and future possible advancements in WPT and explaining why it has still not come into practical utility.
Wireless energy transfer has been around for about a century, but as of yet has only found usage in things like electric toothbrush rechargers and specialty applications such as beaming solar power down from space.
A simple demonstration of it can be constructed at home with ordinary materials. A loop of wire short circuiting a battery will cause a compass needle placed near it to point, and by tapping one end of the wire on and off of its electrode you can cause the needle to twitch. The transverse magnetic field induced in the line acts on the compass, performing work without the use of a physical connection.-
History:
As the wireless art developed during the turn of the 20th century, industry was looking toward a method of wireless energy transfer.
Some of the then scientists are
Hertz: A precursor of this technology can be found in the works of Heinrich Rudolf Hertz in the late nineteenth century. In 1888, Hertz experimented with pulsed power transmission at 500 megahertz.
Tesla: Tesla was able to light gas discharge lamps, he lit ordinary incandescent lamps at full candle-power by currents induced in a local loop consisting of a single wire forming a square of fifty feet each side, which includes the lamps, and which was at a distance of one-hundred feet from the primary circuit energized by the oscillator.
Yagi: In Japan, Hidetsugu Yagi attempted wireless power transmission. In February 1926. Yagi managed to demonstrate a proof of concept, but the engineering problems proved to be more onerous than conventional systems.
The Need for a Wireless System of Energy Transmission:
A great concern has been voiced in recent years over the extensive use of energy, the limited supply of resources, and the pollution of
the environment from the use of present energy conversion systems.
Electrical power accounts for much of the energy consumed. Much of this
power is wasted during transmission from power plant generators to the
consumer. The resistance of the wire used in the electrical grid
distribution system causes a loss of 26-30% of the energy generated.
This loss implies that our present system of electrical distribution is
only 70-74% efficient.
A system of power distribution with little or no loss would conserve
energy. It would reduce pollution and expenses resulting from the need
Methods for wireless energy transfer:
There are three main methods for wireless energy transfer in use today; induction, electromagnetic transmission (power beaming), and evanescent wave coupling.
Induction
Transformers are probably the simplest example of wireless power transfer. The two circuits of a transformer are physically isolated, but transfer (and transform) power by magnetic coupling through induction. Induction cookers are a prime example of how this is used. In an induction cooker, energy is transferred directly and wirelessly into the pot or pan, where it is converted ohmically into heat for cooking. The main drawback to induction, however, is the short range. The receiver must be very close (nearly direct contact) to the inductor unit in order to magnetically couple with it.
Electromagnetic transmission:
Electromagnetic waves, commonly known as light, can also be used to transfer power wirelessly. By converting electricity into light, such as a laser beam, then firing this beam at a receiving target, such as a solar cell on a small aircraft, power can be beamed to a single target. This is generally known as “power beaming”. There are several drawbacks to this, however. First, the conversion to light, such as a laser, is usually very inefficient. Also, atmospheric absorption causes further losses. Finally, this method requires a direct line of sight with the target, and is unsuitable for transmitting too many targets or over a broad area.
Conclusion:
What we wanted to explain in this paper is that the wireless trans-mission of the energy can be converted to electricity and then can be used for many many appliances If this technology develops much faster, we can soon see the radiated world; we mean the energy can be harnessed from any location of the earth.
Let us work and wait for the day and we soon see the electrical revolution drastically changing.