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A group of researchers at the Korea Advanced
Institute of Science and Technology (KAIST) has developed a wireless-power
transfer (WPT) technology that allows mobile devices to be charged at any location
and in any direction, even if the devices are away from the power source. With
this technology, so long as mobile users stay in a designated area where the
charging is available, the device will pick up power automatically, as needed. KAIST
claims that the WPT system is capable of charging multiple mobile devices
concurrently and with unprecedented freedom in any direction, even while
holding the devices in midair or 0.5 m away from the power source, which is a transmitter. The solution uses high-frequency magnetic materials in a dipole coil structure
to build a thin, flat transmitter system shaped into a rectangle with a size of
1 square meter.
Either 30 smartphones with a power capacity of
1 W each or five laptops with a capacity of 2.4 W each can be simultaneously and
wirelessly charged at a 50-cm distance from the transmitter with six degrees of
freedom [the degree of freedom represent mobile devices’ freedom of movement in
three-dimensional (3-D) space], regardless of the devices’ three-axis
positions and directions. This means that the devices can receive power all
around the transmitter in 3-D space. The maximum power transfer efficiency for
the laptops was 34%. The researchers said that fabricating the plane of the transmitter
and receiver coils with the six-degree-of-freedom characteristic was a
bottleneck of WPT for mobile applications. The research team used the dipole
coil resonance system (DCRS) to induce magnetic fields. The DCRS is composed of
two (transmitting and receiving) magnetic dipole coils placed in parallel, with
each coil having a ferrite core and connected with a resonant capacitor.
Read the full article: "Advances in Wireless Power Transfer [Mobile Radio]", IEEE Vehicular Technology Magazine, Volume 10, Issue 4, December 2015. |
