Scientists at the Korea Advanced Institute of Science and Technology (KAIST) have developed an omnidirectional wireless charging technology that can charge multiple devices at once, at a distance and, crucially, at peak efficiency regardless of which way the devices are facing. The technology, said to be safe for humans, is set to be trialled in cafes and offices and could allow for much more convenient charging of mobile devices.
Wireless (or inductive) charging is witnessing a huge surge in popularity since many high-end smartphones have started to include it as one of their flagship features. And soon we might have the ability to charge our devices by the dozen from up to 30 ft (9 m) and coming straight from our furniture.
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But while this technology is advancing in leaps and bounds, there's still one annoying restriction: even when a device can be charged from a distance, it still needs to be kept parallel to the charger to maximize charging speed and efficiency (the latter of which is very low to begin with). For smartphones and tablets, this means they can't be charged very effectively while they're being used.
The new wireless power transfer system developed at KAIST, which was tested on a Samsung Galaxy Note equipped with a special reception coil, has the potential to bridge this gap by introducing the ability to charge devices efficiently regardless of their orientation, while maintaining the ability to charge multiple devices at once and at a distance of up to 0.5 meters (1.6 ft).
Led by Professor Chun T. Rim, and building on technology the team had developed last year, the scientists assembled a thin, flat rectangle-shaped transmitter. While their original power transmitting system employed two magnetic coils placed in parallel, the researchers rearranged them so they would be perpendicular to each other, to generate a rotating magnetic field that makes it possible for devices to receive power from any direction.
An effective wireless transmitting power of 30 watts means the device can, according to the researchers, power either 30 smartphones or five laptops simultaneously. Prof. Rim and colleagues say the level of magnetic flux exposure is within the safety levels set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP), and maximum power transfer efficiency while charging the laptops was measured at 34 percent.
The results were published in last month's issue of the journal IEEE Transactions on Power Electronics, and a spinoff company is now conducting pilot studies to apply this technology in cafes and offices.
You can see the technology in action in the video below.