Wireless power now works over five metres

Imagine charging your smartphone or switching on your TV wirelessly using a power source some distance away!
Researchers have reported a major improvement in the distance of wireless power by extending its range up to 5 metres.
Scientists at The Korea Advanced Institute of Science and Technology (KAIST) have developed a prototype of the Dipole Coil Resonant System (DCRS) that turns a LED television on at a 5-metre distance.
"With DCRS, a large LED TV as well as three 40 W-fans can be powered from a 5-metre distance," Rim said.
"Our technology proved the possibility of a new remote power delivery mechanism that has never been tried at such a long distance," said Rim.

Professor Chun T Rim, and his team proposed an optimally designed coil structure that has two magnetic dipole coils, a primary one to induce a magnetic field and a secondary to receive electric power.

The team used compact ferrite core rods with windings at their centres.
The high frequency AC current of the primary winding generates a magnetic field, and then the linkage magnetic flux induces the voltage at the secondary winding.
"Just like we see wi-fi zones everywhere today, we will eventually have many wi-power zones at such places as restaurants and streets that provide electric power wirelessly to electronic devices," Rim said.

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-metre distance, 471 W at 4-metre, and 209 W at 5-metre.
For 100 W of electric power transfer, the overall system power efficiency was 36.9 per cent at 3 metres, 18.7 per cent at 4 metres, and 9.2 per cent at 5 metres.
"We will use all the devices anywhere without tangled wires attached and anytime without worrying about charging their batteries," said Rim.