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Drawing power from the road


October 1, 2009

The electric car of the future will “refuel” while driving or parked, completely automatically and without physical contact, using the principle of electromagnetic induction

The electric car of the future will “refuel” while driving or parked, completely automatically and without physical contact, using the principle of electromagnetic induction

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It’s starting to look like roads will become much more than simple thoroughfares made of concrete and asphalt in the not too distant future. As we’ve seen, work is already underway to embed them with solar panels and piezoelectric generators to generate electricity. Now engineering company Ingenieurgesellschaft Auto und Verkehr (IAV) is looking to embed them with electrical conductors that would “refuel” the electric cars of the future while they are driving or parked.

The technology is similar to that being developed by researchers at the Korea Advanced Institute of Science and Technology (KAIST) for the Online Electric Vehicle (OLEV), and can already be seen in automobile production plants and large warehouse facilities where robotic floor conveyor vehicles are supplied with power and automatically steered using the same method. As with those systems, inductive loops buried in the roadway would generate a magnetic field to supply the cars with energy without the need for cables and connectors.

This contactless transfer of energy is enabled by taking advantage of the Maxwell electromagnetic laws, whereby an electric current flowing through a conductor generates a magnetic field. In the case of an alternating current, this induces a voltage in a second conductor, even though the two conductors are not in contact with one another. Using precisely controlled frequencies of the applied alternating current, high-efficiency energy transmission from the sending to the receiving electrical circuits is ensured.

Through this principle, IAV is pushing towards a future where roadways would be fitted with buried electrical conductors to generate a magnetic field, while the floorpan of the electric car would be fitted with their counterpart, a non-contacting inductive pickup. This would allow current to be induced to provide power for the vehicle while it is in motion, or stockpiled until the battery is fully charged when the vehicle is parked. Electromagnetic induction also has the benefits of being insensitive to weather conditions and free of mechanical wear.

Not only would the system be able to act as a “range extender” for electric powered vehicles, it would also allow remote control of the vehicles. The primary conductor buried in the road could also carry a control signal to produce a “virtual rail” for the vehicles to follow, much like a slot-free slot car track. The control system would also be needed to activate the charging process when sensors detect with absolute certainty that there was indeed an electric car over the inductive field. IAV suggest the sensors to detect an electric car could take the form of RFID chips, which would also be used to charge the driver for the cost of the power transmitted.

IAV claims that inductive transmission losses are relatively low, at about ten percent, and that the system is highly efficient, which means that only limited sections of the roadway would need to be fitted with induction loops. The system is, however, very sensitive to the distance between the road and the vehicle floorpan, so IAV suggest that the electric vehicles could employ active suspension and opto-electronic measurement techniques to automatically maintain the optimum distance.

IAV is confident that its electromagnetic induction technology will be developed to production-ready status in the next few years. A 1/28 scale model of the system is already “functioning perfectly” the company says, and construction of a demonstration section of “charging road,” and a full-scale test track, are in the planning stages in the German state of Lower Saxony.

Battery-powered vehicles face many obstacles, including the range of the vehicle, the time required to recharge the battery, and the placement of charging points, to name just a few. An electromagnetic induction system offers a solution to these problems, but the cost involved in constructing the infrastructure of such a system would be immense. For this reason, it’s probably more likely that we’ll see the system employed on limited routes for trams or buses before being extended to general roads and streets, but maybe the days of running out of fuel are numbered.

Check out the video below for a graphical demonstration of the IAV system.

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

If you thought asphalt was expensive...

What about where truck also use the lane?


Love the idea, but they do not say what the efficiency rate is. Also there are infrastructure issues to deal with. How will the users pay for this? How will it be enforced (how do you stop someone who has not paid from using it?)? Also there is the issue of installation and removal for repaving. Since they cannot take up an old road with this system in it, there must be a machine that installs it in new road and removes it in old road. Not saying all these issues could not be taken care of, but there is more to it than just burying cables in the road.......


Why not go the other way and use the kinetic energy of any vehicle fitted with magnets to generate current in conductors buried superficially in the road or in side rails along the road. From what I know about rhe law of induction, an enormous amount of current could be generated at a small loss of fuel efficiency. And I bet the feds would pay for the R and D.

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