Category: News
Charge Your Car While Driving
Electric vehicles have been viewed negatively for their low range and for the inconvenience of having to recharge the battery. But a new technology might change the image of electric cars forever. Stanford University has developed a system that charges cars wirelessly while they cruise down the motorway.
The basic concept involves a series of coils that would be embedded under the pavement of the road. The coils emit a magnetic field and as the car passes over them, they pick up energy via a receiving panel underneath the body of the car.
The new technology has the potential to dramatically increase the driving range of electric vehicles and eventually transform long-distance travel, according to researchers of Stanford University’s Global Climate and Energy Project (GCEP).
A wireless charging system would overcome the major drawback of plug-in electric used cars – their limited driving range. “What makes this concept exciting is that you could potentially drive for an unlimited amount of time without having to recharge,” said Richard Sassoon, the managing director of GCEP. “You could actually have more energy stored in your battery at the end of your trip than you started with.”
The wireless power transfer is based on a technology called magnetic resonance coupling. Two copper coils, placed a few feet apart, are tuned to resonate at the same natural frequency. One coil is connected to an electric current, which generates a magnetic field that causes the second coil to resonate. This magnetic resonance results in the invisible transfer of electric energy through the air from the first coil to the receiving coil.
“Wireless power transfer will only occur if the two resonators are in tune,” said Shanhui Fan, an associate professor of GCEP. “Objects tuned at different frequencies will not be affected.”
According to computer simulations, 97% of the energy emitted by the coils is transferred. This, however, is for a single car going down a motorway. Efficiency may differ from region to region due to surrounding noise pollution, weather (snow, ice, etc.), and other external radiation that may affect energy transfer.
The next step is to test the system in the laboratory and eventually try it out in real driving conditions. “You can very reliably use these computer simulations to predict how a real device would behave,” explains Fan. But it will have to be tested on the road before the project’s long-term goal of developing an all-electric motorway can be achieved.
The researchers also want to make sure that the system won’t affect drivers, passengers or the many microcomputers that control steering, navigation, air conditioning and other vehicle operations. “We need to determine early on that no harm is done to people, animals, the electronics of the car or to credit cards in your wallet,” said Sven Beiker of the project. Although a power transfer efficiency of 97 percent is extremely high, Beiker and his colleagues want to be sure that the remaining 3 percent is lost as heat and not as potentially harmful radiation.
As of yet, there is no official estimate of costs of implementing this system on an entire motorway or a timeframe of when it would be possible. The wireless charging technology for moving traffic is only in its early stage of development but its potential is incredibly large.
