Wireless charging on the move hits kW range

April 05, 2018 // By Rich Pell
Researchers at the University of Colorado Boulder (Boulder, CO) have developed a proof of concept for wireless power transfer that could potentially allow electric vehicles to be charged while they are moving.

The researchers' wireless power concept is based on transferring electrical energy through electric fields at very high frequencies. Future electric vehicles could be able to recharge while driving down the highway by drawing wireless power directly from low-cost charging plates installed in the road they say.

Most electric vehicles today can only travel between 100 and 250 miles on a single charge, and charging stations are still far from ubiquitous. That problem, say the researchers, could go away with this technology.

"On a highway, you could have one lane dedicated to charging," says Khurram Afridi, an assistant professor in CU Boulder's Department of Electrical, Computer and Energy Engineering. Afridi notes that a vehicle could simply travel in that lane when it needed an energy boost and could carry a smaller onboard battery as a result, reducing the overall cost of the vehicle.

Qualcomm's Halo automotive ireless charging division has already demonstrated wireless charging of electric vehicles on the move on a test track outside Paris, France. 

Applying wireless charging to a vehicle, especially one in motion, requires a significant amount of power - on the order of tens of kilowatts of power - to be sent across a large physical distance. In addition, a car traveling at highway speeds would not be in range of any single charging pad for more than a fraction of a second - so such pads would need to be placed every few meters to provide a continuous charge.

Most wireless power technology research to date has focused on transferring energy through inductive charging - i.e., using magnetic fields. Magnetic fields - at strength levels appropriate for substantial energy transfer - are easier to generate than equivalent electric fields. However, magnetic fields travel in a looping pattern, requiring the use of fragile and lossy ferrites to keep the fields and the energy directed, resulting in an expensive system.

Electrical fields, however, naturally travel in relatively straight


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