Korea’s Electric Buses Bring Wireless Charging to the Streets – Literally
Image Credit: Lan Yoon via Flickr

Korea’s Electric Buses Bring Wireless Charging to the Streets – Literally


Wireless charging is becoming an increasingly common smartphone feature – but the Korea Advanced Institute of Science and Technology (KAIST) decided to think big about the relatively new technology’s potential. KAIST, in a partnership with the South Korean town of Gumi, has developed a pair of electric commuter buses that recharge wirelessly while driving over specially-equipped roads.

The Online Electric Vehicle (OLEV) motor coaches, which run round-trip journeys of 24 kilometers (15 miles) while completing their stops, are special because they can be charged while driving or stationary. Built with special electrical coils underneath their chassis, the buses collect energy while driving over power lines that are embedded in the asphalt – thus removing the necessity to plug in at a charging station from time to time.

“OLEV receives power wirelessly through the application of the "Shaped Magnetic Field in Resonance (SMFIR)" technology. SMFIR is a new technology introduced by KAIST that enables electric vehicles to transfer electricity wirelessly from the road surface while moving,” said EurekaAlert’s Lan Yoon.

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Yoon continued: “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 percent to 15 percent of the entire road, requiring only a few sections of the road to be rebuilt with the embedded cables.”

As far as power is concerned, EarthTechling reports that “each bus receives 20 kHz and 100 kW (136 horsepower) electricity at an 85 percent maximum power transmission efficiency rate while maintaining a 17 cm air gap between the underbody of the vehicle and the road surface.”

KAIST’s breakthrough was hailed as one of the year’s top 10 emerging technologies by the World Economic Forum earlier this year. KAIST had spent many years perfecting the large-scale wireless charging, starting in 2010 with an OLEV tram car that carted passengers around a Seoul amusement park. The organization will also begin testing high-speed OLEV trains in September.

According to Txchnologist, “Proponents [of OLEV] say that the technology banishes overhead power lines and rails for electric trams and buses, dramatically lowers the costs of railway wear and tear and allows smaller tunnels to be built for electric vehicle infrastructure, lowering construction costs.”

Following the successful deployment of the first two OLEV buses in Kumi, city officials plan to add 10 more to their fleet by 2015.

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