CUTTING THE POWER CHORD

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WiTricity is taking wireless power to the next level. Its power transfer technology is already impacting how computers and cars are charged. Electronic eyewear is next.

For more than 200 years, electricity has been conducted through wires. That necessity tethers the connected device to its power source. WiTricity aims to unshackle power-needy devices by providing wireless power to a wide range of products, including electronic eyewear.

WiTricity was born when an MIT professor was awakened a few nights by his cellphone’s alarm warning that his unplugged cellphone’s power was nearly gone. He decided then that he’d find a way to wirelessly power it. Working with colleagues, the team began working on highly resonant wireless power transfer (HRWPT). To prove the concept worked, the team demonstrated it could move 60 watts over a six-foot distance with high efficiency. With patents acquired, the company was formed and a team including engineers and scientists began work.


How HRWPT works

David Schatz, vice president of sales and business development for WiTricity, explained that HRWPT is accomplished by magnetic resonance, which uses oscillating magnetic fields to exchange energy. To do this, an energy source (such as a battery or electricity from the power grid) provides power to an electronic circuit that turns that power into an oscillating magnetic field, while a similar device some distance away couples to this magnetic field and converts it back into electrical energy. The result: power transfer without wires that is efficient, safe and cost effective.

Schatz suggests that a way to visualize this is to recall what happens when an opera soprano sings a loud, high note. The vibrations of the note being sung and the intensity of that sound fill a room with strong oscillating sound waves. A crystal wine glass that inherently resonates at the same frequency as the singer’s note can be shattered by the energy transferred to the glass from the sound waves of the singer’s voice. “This demonstrates that if you have a source of energy and a device that can capture that energy, and the two are properly tuned to each other, you can exchange energy wirelessly over a distance,” Schatz explained. While WiTricity uses magnetic waves instead of acoustic waves, the process is essentially the same.

The traditional way to transfer energy using magnetic fields is through magnetic induction that requires two essentially identical devices to be precisely aligned and within millimeters of each other. “With magnetic resonance, you can separate the devices by four times the size of the devices or more,” Schatz explained. Magnetic resonance is not affected by most materials-with the exception of
metals-so textiles, skin, bone, rubber, glass, concrete, water and more are not limiting factors. That’s one reason this technology is being considered for applications such as powering pacemakers, cochlear implants, hearing aids and a host of other devices.


HRWPT and wearables

In the optical world, wireless power is an attractive option for wearable electronics. Think eyewear that lets you view pictures and videos, read and answer email, view GPS information, listen to audio, change lens color electronically, change lens power electronically, use LED lights and more.

This new eyewear category needs power, but batteries must be small enough to fit into a modest-sized temple, which usually means limited battery life. Though some devices can charge once a day, others will benefit from a wireless power device the user carries. While consumers will find wearables appealing, there are a lot of industrial and military applications for it.

WiTricity’s mission is to provide wireless power solutions to a wide range of products, and it plans to do that by applying its HRWPT technology. “We are technology providers,” Schatz mentioned. “We work with other companies who have applications and want this core technology to implement as a subsystem component into their products.” The company sees a large, growing opportunity in the eyewear space, although it will take some time to develop. The days when walking into a room (or pulling into your driveway) and having your computer or electric car automatically charge are not far off.


Ed De Gennaro, MEd, ABOM, is director, professional content of First Vision Media Group.

 

WHERE TO FIND IT: WiTricity 617-926-2700 witricity.com

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