电能无线传输技术再现曙光.doc

目前，数百家公司都在投资电磁场无线电能传输技术，而且已经取得了一些进展。这项新技术的工作原理如何？它到底什么时候才能取代有线电缆，投入使用？又会给我们的生活带来哪些改变？ 电能无线传输技术再现曙光 Backed by the financier J.P. Morgan, Nikola Tesla, the inventor and rival to Thomas Edison, built in the early 1900s the Wardenclyffe Tower, a 187-foot-high structure on Long Island, which he said could transmit electricity wirelessly. The project failed, and Tesla ended up broke. (In an earlier experiment in Colorado, Tesla had wirelessly lit up 200 lamps over a distance of 25 miles, but pedestrians witnessed sparks jumping between their feet and the ground, and electricity flowed from faucets when turned on. Oops.) Fast-forward over a century, and wireless electricity is finally gaining some traction. More than one hundred companies including startups such as WiTricity and ProxybyPower and giants such as Toyota (TM), Intel (INTC), Samsung, and Foxconn are investing in the technology. The challenge: to take the wires out of the power equation by transmitting electricity through magnetic fields. When in the atmosphere, electricity exists as a magnetic field. The trick is to capture it safely to recharge devices. Todays electric toothbrushes charge wirelessly -- as power is transmitted through a magnetic field from the charger to the brush. You can already buy wireless recharging pads: Place your cellphone on a pad thats plugged into the wall, and it will recharge. These pads, however, have their limitations -- the cellphone has to be in the right position, and it can take a long time. A New Zealand company called PowerbyProxy has demonstrated a system where you can put multiple cellphones on a pad in any position, and it will charge the devices as fast as a traditional charger. Samsung last month invested $4 million in the company. The next step: charging without being so tied to a pad. Thats the technology a Watertown, Mass., company named WiTricity is developing. Based on work done at MIT, the technology -- on which the company holds exclusive patents -