25 Feb 2015

Revolutionary new wireless charging technology

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Nikola Tesla, the pioneer of radio and the modern electrical transmissions systems proposed a global system of wireless transmission of electricity or wireless power more than a century ago. But sadly, the technology couldn’t evolve out of the paper because of a key obstacle in it’s development – very low efficiency of transferred power over distance. Few years back though, a team of

MIT researchers led by Professor of Physics Marin Soljacic took definitive steps toward more practical wireless charging by wirelessly lighting a 60 watt light bulb using two large copper coils, with similarly tuned resonant frequencies, that transferred energy from one to the other over the magnetic field at a distance of 8 feet.

This clearly demonstrated the usability of this technology in consumer products. The team has advanced their technology over time with increasing the efficiency of the system. “It’s probably a dream of any professor at MIT to help change the world for a better place,” says Soljacic, a WiTricity co-founder who now serves on its board of directors. “We believe wireless charging has a potential to do that.”

The wireless power technology startup, WiTricity is aiming to free the world from wires with the mission to avail consumers with the technology using which they need not carry wires and power bricks.

It could also lead to benefits such as smaller batteries and less hardware – which would lower costs for manufacturers and consumers. WiTricity was founded in 2007 after Soljacic and a team of five MIT researchers published a proof-of-concept experiment in Science.

In the experiment, the researchers used two copper coils, about two feet across, each a self-resonant system. One transmitting coil was connected to an AC power supply, while another connected to a 60-watt light bulb.

The transmitter emanated a magnetic field, oscillating at megahertz frequencies, which the receiver matched, ensuring a strong coupling between the units and weak interaction with the rest of the environment, including nonmetallic materials – and humans. In fact, they demonstrated that they could light the bulb, at roughly 45 percent efficiency, with all six researchers standing in between the two coils.

A 2010 paper published in Applied Physics Letters by Soljacic and colleagues made another breakthrough: They found that when adding more receiver coils, power transfer efficiency climbs by more than 10 percent. In that experiment, they used larger transmitting coils, but receiving coils that were only a foot across, resulting in a power output of 50 watts from several feet away.

There are similar technologies available in the market for instance, traditional induction charging, which uses an electromagnetic field to transfer energy between two coils, used in transformers and wireless toothbrushes. In the past two years, there’s also been an increase in wireless cell phone charging pads based on induction. “These work well, but only over very short distances, so they’re nearly touching,” Soljacic says. “They become dramatically inefficient when the distance increases.”

At present, WiTricity technology charges devices at around 6 to 12 inches with roughly 95 percent efficiency from 12 watts for mobile devices to 6.6 kilowatts for cars. The team is focusing on how to increase the distance, scale and efficiency of the device. They have also developed repeaters: passive devices that extend the distance of the power transfer.

The applications are endless and the odds of making this a viable technology are more than possible. Information/Source: phys.org/news/ If you know of any such technology that can replace the idea of WiTricity then don’t hesitate from mentioning it in the comments section below.

Watch the video below on the introduction of WiTricity Technology which is about to revolutionize the way we charge our gadgets.