Wireless Chargers!
Published on 17 Apr 2007 at 9:12 pm.
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Filed under Energy, Entrepreneurship, Inventions, Research, Solutions.
Today Ben, who is a student in my electromagnetism class, told me that he heard that wireless chargers are about to hit the market. The problem is that while radio communications works well, radio power transfer is hampered by the fact that the electromagnetic radiation spreads out with much of it being lost to the environment.
Powercast apparently has solved some of the basic problems with wireless power transfer. Their white paper claims that their Powerharvester can capture 70% of the theoretical maximum power anywhere within the Powercasters effective range. All Powerharvesters within range will be recharged. This will be extremely convenient as we will be able to place any device to be recharged near the Powercaster and it will be recharged. No more plugs! Furthermore, the circuitry needed is relatively small, and if the white paper is accurate, it is about 1 cm by 2 cm.
Spashpower is another company preparing to unleash wireless recharging via the SlashPad, which is a pad on which one places the device for recharging.
Meanwhile research on wireless recharging continues. Marin Soljacic an assistant professor in MIT’s Department of Physics and Research Laboratory of Electronics has been working on this problem as well. He presented his results at the 2006 American Institute of Physics Industrial Forum in November 2006. An MIT article can be found here. His solution is to use non-radiative energy transfer so that the system works much like a transformer. The only difference is that the magnetic flux is not coupled with an iron core. They came up with their designs through computer simulations, and their results demonstrate that one could recharge a device wirelessly within a range of about a meter. One recharger per room of a house would allow devices to be continuously recharged.
This will be extremely important technology for robotics. Robots would need only to follow the radio frequency power gradient until it is within recharging range.
Kevin Knuth
Albany NY
