By Jeyuup S. KwaakA slew of companies world-wide are betting on electric buses as the future of mass transit, and the direction most are taking is towards wireless charging while on the move.South Korean engineers claimed a victory earlier this month when they beat rivals by fielding the world’s first wireless electric buses that can charge in motion. The so-called On-Line Electric Vehicle buses recharge using power supply underneath the pavement as they roll on the 15-mile course in Gumi, a regional city 150 miles southeast of Seoul. The in-motion process known as “dynamic charging” increases fuel efficiency by reducing the buses’ battery size and puts an end to lengthy charging sessions at the end of the route, the engineers say. The buses can also charge while parked.
Engineers from the Korea Advanced Institute of Science of Technology say the power transfer system they devised shapes electromagnetic fields to a specific direction to minimize lost energy while in transit. The receiver picks up 100 kilowatts of electricity at a 20 kHz frequency with up to 85% efficiency, according to the institute. The buses also employ “regenerative braking” found in hybrid cars, which converts energy from the vehicle’s motion to help power it.
Electric buses that charge wirelessly have been in service for a decade in Turin, Italy. But they have to be parked while charging at the designated points. These buses made by Conductix-Wampfler, subsidiary of Delachaux Group, would lower the pick-up device to the road surface to pick up the charge. – Yahoo News
