Researchers have succeeded in developing a device that can charge about 40 smart phones simultaneously, even if the power source is 5 meters away.
Chun T. Rim, a professor of Nuclear and Quantum Engineering at KAIST, and his team showcased, on April 16, 2014 at the KAIST campus, Daejeon, Republic of Korea, a great improvement in the distance that electric power can travel wirelessly.
They developed the "Dipole Coil Resonant System (DCRS)" for an extended range of inductive power transfer, up to 5 meters between transmitter and receiver coils.
Since MIT's (Massachusetts Institute of Technology) introduction of the Coupled Magnetic Resonance System (CMRS) in 2007, which used a magnetic field to transfer energy for a distance of 2.1 meters, the development of long-distance wireless power transfer has attracted much attention for further research.
Scalable and slim with a size of 3 m in length, 10 cm in width, and 20 cm in height, DCRS is significantly smaller than CMRS. The system has a low Q factor of 100, showing 20 times stronger against the environment changes, and works well at a low frequency of 100 kHz.
The team conducted several experiments and achieved promising results: for instance, under the operation of 20 kHz, the maximum output power was 1,403 W at a 3-meter distance, 471 W at 4-meter, and 209 W at 5-meter. For 100 W of electric power transfer, the overall system power efficiency was 36.9 per cent at 3 meters, 18.7 per cent at 4 meters, and 9.2 per cent at 5 meters.
