Wireless charging electric bus debuts in South Korea

The Online Electric Vehicle (OLEV), developed by the Korea Advanced Institute of Science and Technology (KAIST), removes the need to stop at a charging station.

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Two OLEV buses will run an inner city route between Gumi Train Station and In-dong district, for a total of 24 km roundtrip. The bus will receive 20 kHz and 100 kW (136 hp) electricity at an 85% maximum power transmission efficiency rate while maintaining a 17cm air gap between the underbody of the vehicle and the road surface.

OLEV receives power wirelessly through the application of the “Shaped Magnetic Field in Resonance (SMFIR)” technology. This is a new technology introduced by KAIST that enables electric vehicles to transfer electricity wirelessly from the road surface while moving. Power comes from the electrical cables buried under the surface of the road, creating magnetic fields. There is a receiving device installed on the underbody of the OLEV that converts these fields into electricity. The length of power strips installed under the road is generally 5% to15% of the entire road, requiring only a few sections of the road to be rebuilt with the xembedded cables.

The OLEV battery is one-third of the size of the battery from a regular electric car. The vehicle complies with the international electromagnetic fields (EMF) standards of 62.5 mG, within the margin of safety level necessary for human health. The road has a smart function as well, to distinguish OLEV buses from regular cars — the segment technology is employed to control the power supply by switching on the power strip when OLEV buses pass along, but switching it off for other vehicles, thereby preventing EMF exposure and standby power consumption. As of today, the SMFIR technology supplies 60 kHz and 180 kW of power remotely to transport vehicles at a stable, constant rate.

After the successful operation of the two OLEV buses by the end of this year, Gumi City plans to provide ten more such buses by 2015.

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