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New tech could beam power from roadside stations to passing electric cars

By

November 14, 2013

The small-scale prototype of the system

The small-scale prototype of the system

Among the concepts put forth for decreasing the range anxiety associated with electric cars, one is to embed electrical coils within the asphalt. This would allow vehicles to wirelessly draw power from the road as they traveled, although it would also involve having to tear up existing roads to install those coils. An alternative could be on its way, however. Scientists at North Carolina State University are developing a system in which power could be transmitted from stationary roadside stations to mobile receiver coils in cars passing by.

Previous attempts at doing the same sort of thing have had their drawbacks.

In one case, transmitting coils that were larger than the receiving coils were used, in order to deliver a high amount of power. Unfortunately, as the university explains, "This approach created a powerful and imprecise field that could couple to the frame of a car or other metal objects passing through the field." This means that the system wasn't very efficient, plus all the electromagnetic radiation being flung around raised safety concerns.

In another case, a larger number of smaller coils were used. While this increased efficiency and decreased the danger, putting it into roadside use could be complex and expensive, as many carefully-positioned coils would be required.

Instead, the North Carolina researchers are using transmitting and receiving coils that are the same size as one another – the best arrangement for efficient transfer of energy. When no receivers are around, the transmitter emits a safe, low-level electromagnetic field. As a receiver comes into range, however, it triggers the transmitter to temporarily increase its output by 400 percent. Once the receiver has passed out of range, the output drops back to its previous level.

Out on the road, that could translate into a system that only fully fires itself up when an electric vehicle is going by. The current proof-of-concept model puts out a maximum of 0.5 kilowatts, although lead scientist Dr. Srdjan Lukic states that his team is working towards a scaled-up 50 kW version.

A paper on the research was recently published in the journal IEEE Transactions on Power Electronics.

Source: North Carolina State University

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth
8 Comments

Great concept... But stupid - it requires that we live in a communistic or highly socialistic society where we share rather than gobble up everything we can for ourselves...

Christoffer Thor Wang Sperling
14th November, 2013 @ 08:59 pm PST

How does one charge for the electricity?

Slowburn
15th November, 2013 @ 02:01 am PST

You could use a wireless payment method based on an app on a phone to charge per unit used. No need for a communist revolution comrades.

Paul Adams
15th November, 2013 @ 05:57 am PST

I recall seeing a film of an electrical helicopter being flown (tethered) with power fed in from the ground thirty, maybe forty years ago. This is hardly new stuff.

Chris Goodwin
15th November, 2013 @ 07:11 am PST

It's all about efficiency. The best that the road-embedded systems have achieved, with distances between the transmitter and receiver coils of 20 cm is 80%, so any kind of roadside system that tries to put this technology on existing roadways is going to have putrid efficiency due to the distance involved (at least a couple of meters or more). A tight beam microwave energy transmitter has higher efficiency, and has been demonstrated successfully to fly small model aircraft, but the safety issues are a tremendous challenge.

Pat Kelley
15th November, 2013 @ 09:39 am PST

"How does one charge for the electricity?" A wireless payment method would work, of course. However, it may not be a problem. Tesla Motors is already offering FREE recharging of its Model S. on selected superhighways, using energy collected from solar panels. Small solar panels are already being used to power highway signs. Roadside transmission coils could be placed on both sides of a two lane highway and broadband bursts of microwave could be used to limit radiation levels in any specific frequency range, which is what causes the radiation hazard. More problematical is what to do in traffic snarls or three lane highways. However I am certain a solution can be worked out.

Robert Fallin
15th November, 2013 @ 03:39 pm PST

Shades of Nicola Tesla! TESLA pioneered this concept among others involving transmission of power sans connected cables or wires! He actually had modified a Pearce Arrow automobile to accomodate the 80 HP electric motor which powered the car! For a variety of causes and reasons, Tesla abandoned the project after operating and demonstrating the car to various potential entrepreneurs, none of which could conceive of anything actually operating 'electrically' without wires! Humanity had not yet evolved out of the 'Stupid' phase of development, and could not accept that without 'Money' as the motivational factor, the world simply could not exist and survive! Guess Tesla 'Proved' that assessment to be factual and correct!

Robert Arthur Gillis
15th November, 2013 @ 07:27 pm PST

Is there some reason that street lamps couldn't be installed, when they need to be replaced, that would be charging stations as well, where appropriate.

Paul Adams
17th November, 2013 @ 12:27 am PST
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