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Print 19 comment(s) - last by Flunk.. on Aug 29 at 5:22 PM

Buses can be charged as they drive

The Korea Advanced Institute of Science and Technology has developed a pair of electric buses called Online Electric Vehicles or OLEV. These buses are different from your typical electric vehicles that have to be parked to recharge the batteries. Instead, they can recharge while driving down the road.
 
Electricity is sent to the bus via cables buried in the road with an 85% maximum power transfer efficiency rate (the wireless charging technology is able to supply 60 kHz and 180 kW of power at a stable and constant rate). There is a gap of just under seven inches between the underbody of the electric bus and the road surface. The charging system uses Shaped Magnetic Field in Resonance [PDF] to transfer power to the bus while it’s in motion.

 
The underbody of the bus has a receiving device that is able to convert the magnetic fields into electricity. The power strips needed to power the bus only cover 5 to 15 percent of the road surface, so only small sections of road have to be rebuilt to provide service.

Both of the OLEV buses are currently operating in the city of Gumi, South Korea. As of August 6, the buses are running an intercity route between the Gumi Train Station and In-dong district spanning 15 miles round-trip.
 
The technology used in the OLEV buses is an offshoot of tech used to power trams at an amusement park in South Korea.

Sources: Phys.org, KAIST



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RE: huh
By Motoman on 8/7/2013 5:12:43 PM , Rating: 2
quote:
cables buried in the road with an 85% maximum power transfer efficiency rate


The 85% is what's going to stop that from happening.

They can probably get away with that for the purposes of a relatively small number of city buses in a given metro area.

But it's a non-starter issue for widespread use.


RE: huh
By Jeffk464 on 8/7/2013 5:46:52 PM , Rating: 2
Electric motors have a much higher efficiency rating than gasoline engines. So I'm thinking a loss of 15% is probably really do-able.


RE: huh
By Hoser McMoose on 8/7/2013 6:36:45 PM , Rating: 2
Electric motors do have higher efficiency, but this 15% loss is only one of many places where energy is lost in the whole chain of things, the biggest of which is simply in generating the electricity in the first place.

Probably not a fatal flaw overall, and even with a wired connection there is going to be some loss in transfer power from the wall to the car (a lot less than 15%, but greater than zero), but it is just one more area of efficiency loss that makes the solution less attractive.


RE: huh
By Paj on 8/8/2013 7:29:47 AM , Rating: 2
I;d say that pretty good, when you consider that conventional ICEs lose up to 75% of the energy generated as waste heat.


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