South Korean electric buses use dynamic wireless charging

The city of Gumi in South Korea has deployed two electric buses that use dynamic wireless charging. Dynamic wireless is a particularly exciting technology, as it has the potential to remove several of the objections associated with EVs. In a public transport context, it eliminates the need for unsightly overhead wires. Further down the road, it could do away with long charging times and bulky, expensive batteries.

Gumi’s new Online Electric Vehicles (OLEVs) were developed by the Korea Advanced Institute of Science and Technology (KAIST), which has been working on dynamic wireless since 2009.

The two OLEV buses will serve a 24 km inner-city route between Gumi Train Station and the In-dong district. They receive electricity at 20 kHz and 100 kW, with an 85% maximum efficiency rate and a 17 cm air gap between the underbody of the vehicle and the road surface.

Power comes from cables buried under the surface of the road, and is transmitted to a receiving device on the underbody of the OLEV. The buried power strips cover 5-15% of the length of the road, requiring only a few sections to be rebuilt with the embedded cables. 

The OLEV’s battery is only a third the size that an ordinary EV would require. The system is smart enough to distinguish OLEV buses from regular cars, switching on the power strip when OLEV buses pass, but switching it off for other vehicles, thereby preventing EMF exposure and standby power consumption.

“It’s quite remarkable that we succeeded with the OLEV project so that buses are offering public transportation services to passengers,” said Professor Dong-Ho Cho of KAIST. “This is certainly a turning point for OLEV to become more commercialized and widely accepted for mass transportation in our daily living.”

After the successful conclusion of the OLEV pilot at the end of this year, Gumi plans to provide ten more such buses by 2015. 

 

Source: KAIST via Green Car Congress