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Harnessing magnetic fields could allow phones, cars to charge on the move

A bit like the way that products marketed as hoverboards don’t actually hover, today’s wireless charging technology is not all that wireless. Sure, you do not have to physically plug your phone in to get it charging, but placing your phone on a charging pad to juice up its battery still is not quite the wire-free dream we have been hankering after.

A new piece of research from researchers at Stanford University could make that dream a reality, however. In a paper published in the journal Nature, investigators describe a kind of ambient charging environment that would allow devices to start charging whenever you walk into a room — a bit like a Wi-fi setup you instantly connect to when in close proximity.

“What we’ve demonstrated is robust wireless power transfer,” Professor Shanhui Fan, a researcher on the project whose work involves computational and experimental photonics research, told Digital Trends. “It’s a system in which the transfer efficiency remains high as the receiver moves over a range of distances, without need for any external tuning. It means that you could walk around in a room, with your phone continuing to get charged.”

The method the team developed involves a large magnetic field “amplifier” that can power a device wirelessly. In their proof-of-concept demonstration, the simple device the researchers chose to focus on was an LED light which they moved further and further away from its power source. The work built on research developed by the Massachusetts Institute of Technology in 2007, which showed that it is possible to transmit electricity wirelessly over a distance of several feet to a stationary object. This time, however, the Stanford researchers augmented the setup with a voltage amplifier and feedback resistor. As Fan noted, the result is a system that can work out the correct frequency for variable distances without a human needing to fine-tune it along the way.

The idea of true wireless charging phones is certainly exciting, but Fan said there is another larger goal involved: Wirelessly charging electric cars. “If you’re driving on the road, and somehow energy can be sent into your electric car, that would be very useful,” he said. “It’s also an example of a situation in which it wouldn’t be practical to do plugged-in charging, since you would be driving at the time.”

There is still more work to be done on increasing the amount of electricity that can be transferred using the method, but — provided this research advances as planned — this could turn out to be the start of something very significant.

“I think it’s a fairly practical technology, but it’s always difficult to predict commercialization,” Fan said. “What we’ve currently done is to file a patent application, which takes us one step closer.”

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