|KAIST’s operational OLEV. Click to enlarge.|
The Korea Advanced Institute of Science and Technology (KAIST) has developed and deployed a prototype implementation of its online electric vehicle (OLEV) technology that picks up electricity from power cables buried underground through a non-contact magnetic charging method. The OLEV demonstrator developed by KAIST replaces a trackless combustion-engine train running inside Seoul Grand Park.
KAIST called the non-contact charging of vehicles while running, idling, or parking an important and practical technology necessary for the development of commercialized electric vehicles.
The power pickup equipment installed underneath 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 the mitigates the burden of equipping electric vehicles with large battery packs—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. A selective provision of power to vehicles with the pickup equipment relieves safety concerns about electromagnetic radiation exposure to pedestrians or other conventional vehicles. EMF test results for OLEV are well below the 1998 the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guideline, 62.5mG at 20kHz.
If the OLEV charging method is applied to the public bus system in South Korea, the underground power lines would need to be installed on only 20% of the total bus route at places like bus stops, parking lots, and intersections, KAIST said.
In terms of power system transmission efficiency, KAIST’s research team achieved a maximum pick-up capacity of 62 kW/h, 74% with an airgap height of 13cm from the road to the bottom of the vehicle.
Comprising one engine and three passenger cars, the OLEV travels along a total length of 2.2km. There are four sections of power supply infrastructure on the route (Sections 1, 2, and 3: 122.5 meters long each, and Section 4: 5 meters long). The power supply cables were installed under the road surface for a total of 372.5 meters, 16% of the total distance of the 2,200 meter route.
The city government of Seoul and KAIST signed a Memorandum of Understating (MOU) on the development of the online electric vehicle in August 2009.
KAIST has submitted more than 120 applications for patent rights in connection with the development of OLEV, and has set up a roadmap for research and development that will lead to the commercialization of OLEV:
- Development of core technology for the power supply and collection system (2009)
- Development of test prototype for OLEV and common core technology of electric bus (2010)
- Development of practical prototype technology for OLEV (2011)
- Development of standard prototype technology for OLEV (2012)
- Introduction of commercial product to market (2013 and beyond)