RANGE ANXIETY...I'VE GOT TO GIVE IN:

One way to extend the range of electric vehicles may be to provide power wirelessly through coils placed under the surface of a road. But charging moving vehicles with high-power wireless chargers below them is complex.

Researchers at North Carolina State University have developed a method to deliver power to moving vehicles using simple electronic components, rather than the expensive power electronics or complex sensors previously employed. The system uses a specialized receiver that induces a burst of power only when a vehicle passes over a wireless transmitter. Initial models indicate that placing charging coils in 10 percent of a roadway would extend the driving range of an EV from about 60 miles to 300 miles, says Srdjan Lukic, an assistant professor of electrical engineering at NCSU.

Wireless charging through magnetic induction--the same type typically used for electronic toothbrushes--is being pursued by a number of companies for consumer electronics and electric vehicles (see "Wireless Charging--Has the Time Finally Arrived?"). Such chargers work by sending current through a coil, which produces a magnetic field. When a car with its own coil is placed above the transmitter, the magnetic field induces a flow of power that charges the batteries.

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