The commercialization of Online Electric Vehicle (OLEV) technology developed by researchers at the Korea Advanced Institute of Science and Technology (KAIST) has taken another step forward with the introduction of an OLEV “train” for public transportation in Seoul’s Grand Park in Gwacheon City. The vehicle picks up electricity from power cables buried underground through a non-contact magnetic charging method and replaces a trackless combustion engine train running inside the park.
The power pickup equipment installed underneath the OLEV collects electricity from a roadway and distributes the power either to operate the vehicle or for battery storage. Whether running or stopped, the OLEV constantly receives electric power through the underground cables. As a result, OLEV mitigates the burden of equipping electric vehicle with heavy, bulky batteries – the OLEV's battery size is one-fifth of the batteries installed in electric vehicles currently on the market.
A road embedded with underground recharging strips is divided into several segments so that, when a car drives on a certain segment, a sensor in the segment is turned on, and the car above the segment picks up electricity. Because charging occurs in transit there is no need to establish charging stations or set aside time for recharging that leaves the vehicle is idle.
KAIST says that if the OLEV charging method is applied to the public bus system in South Korea, the underground power lines need to be installed on only 20 percent of the total bus route at places like bus stops, parking lots, and intersections.
Also removing direct contact with charging sources prevents electrical hazards, such as electric shock. And the contactless-charging method is safe for pedestrians and other conventional vehicles, with electromagnetic radiation (EMF) test results for OLEV being well below the 1998 the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guideline, 62.5mG at 20khz.
The OLEV train running at Seoul Grand Park consists of one engine and three passenger cars and travels along a total length of 2.2km (1.36 miles). The route contains four sections of power supply infrastructure – three sections measuring 122.5 meters (402 feet) long and one five meters (16.4 feet) long. The power supply cables were installed under the road surface for a total of 372.5 meters (1,222 feet), which is 16 percent of the route’s total distance.
In terms of power system transmission efficiency, KAIST's research team achieved a maximum pick-up capacity of 62kw/h, 74% with an airgap height of 13cm (5.1-in) from the road to the bottom of the vehicle – a 12cm (4.7-in) airgap is required for practical vehicle application in accordance with South Korean law.
The city government of Seoul and KAIST signed a Memorandum of Understating (MOU) on the development of the online electric vehicle in August 2009. The two organizations agreed to introduce eco-friendly vehicles to the city's public transportation system, beginning with a bus route in Seoul.
The introduction of the OLEV train is the second step in KAIST’s roadmap that leads to the eventual commercialization of the technology. The next step involves the development of practical prototype technology for OLEV (2011), followed by the development of standard prototype technology (2012) and finally the introduction of a commercial product to the market in 2013.
