Wireless Power Supply

Other Unique Engineering Ideas

Scientist in the US have created what they believe to be the worlds first safe wireless power supply, a system which can be adapted for each and every electricity powered appliance in the home.  Within just 3 to 5 years we could be saying goodbye to those tangled cables behind the back of your desk, and the mess of wires behind your TV set.

1. Description

2. Why

3. How

4. Future Trends

5. Related Links

Description

The cables that once restricted electronic equipment are gradually being rendered unnecessary by wireless communication technology, and as circuits shrink, only the power cords and huge batteries continue to chain mobile gear down.Research into using wireless technology to supply power to terminals began about a century ago, when the first electronics technology appeared, and it is finally beginning to be realized providing means to cut the final chains. It entered limited use about a decade ago, and is expected to see widespread use in everyday applications like mobile phone handsets and portable music players from the second half of 2007 through 2008.

Why

With wireless transmission of electric power, irritating tasks such as replacing batteries or using a charger to recharge batteries will be drastically reduced. In some cases, it will be possible to dispense completely with power cords. Offers completely wireless power supply and charging. Diverse commercial applications are expected from the second half of 2007.These technologies are attracting so much attention from manufacturers and researchers lately because of

  • market growth

  • developments in technology

  • delays in competing technologies 

How

The power supply works by using the concept of resonance, which allows the efficient transmission of energy between items which resonate at the same frequency.  They have likened the theory to that of an opera singer smashing a glass of wine with their voice - the glass will only smash if the liquid is filled to a level which ensures both the singers voice and the glass resonate on the same frequency. A simple copper antenna designed to have long-lived resonance could transfer energy to a laptop with its own antenna resonating at the same frequency. The computer would be truly wireless. Any energy not diverted into a gadget or appliance is simply reabsorbed.Wireless power supply technologies at present can be divided into three groups according to their principle of operation. The first non-contact technology achieving widespread adoption in many portable terminals is electromagnetic induction. Two coils are brought close to each other and when current is passed through one, the generated magnetic flux causes electromotive force to be generated in the other. Another technology very close to commercial use makes use of the fact that energy can be transmitted and received directly as radio waves. This is fundamentally the same principle of operation as used in the crystal sets of a century ago, with alternating current (AC) radio waves converted into direct current (DC) without amplification. Recent improvements in efficiency have made it possible to consider this technology for commercial applications. The third principle is electromagnetic resonance. Resonance technology is extensively utilized in electronics, but this specific application uses only the electric or magnetic field, instead of electromagnetic waves, current, etc. A group under Asst Prof Marin Soljacic, Physics Dept, Massachusetts Institute of Technology (MIT) of the US, was the first in the world to announce its potential for use as a power supply technology, in November 2006.

Future Trends

In Japan, NTT DoCoMo Inc is actively developing similar technology, with the first prototype mobile phone supporting wireless charging developed in 2005.Motorola Inc of the US and other firms in the US are already developing mobile phones utilizing the technology.Apple Inc of the US applied for a patent relating to a non-contact charger for its iPhone, iPod portable music player and other products in February 2007, pointing up the high level of interest in the industry. Non-contact charging systems for mobile phones will go on sale in Europe in the second quarter of 2007, for example (Fig 1). This charging technology leaves a gap of a few millimeters between charger and handset, with no metal pins in contact.

Keywords

Non-contact charging, Wireless Power Supply, WiTricity, Battery Charging

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