[Courtesy of the Korea Railroad Research Institute]
SEOUL -- South Korea's state-run railway research body has transferred core technologies to domestic companies to commercialize a wireless power supply system for light rail. The technology for designing parts, which wirelessly transmit power to light rail, and applying the supply of wireless power can help design a safer and more efficient wireless power supply railway infrastructure.
The Korea Railroad Research Institute (KRRI) said it has signed a contract with three companies -- Woojin Industrial Systems, Metrotech, Daedong Capacitor -- to transfer key technologies that also include a power stabilization device that efficiently converts, store and use collected power, and high-capacity capacitor technology for high frequency.
The institute has completed a 40,000-kilometer (24,850-mile) test run at its test line in Gyeongsan to ensure the stable operation of its wireless power supply system and verify the performance and effectiveness of technology by implementing 1MW power, the world's largest capacity. The introduction of wireless power supply technology in the 200m acceleration section can remove long high-pressure wires installed along the track.
While existing systems expose high-voltage wires and make wires installed on walls or upper parts stand out, KRRI said its wireless power supply lines are covered with insulating covers and can be installed or buried on the floor, greatly improving safety and urban aesthetics. "The paradigm of power supply is changing with wireless technology," KRRI president Han Seok-youn said in a statement on October 20.
The institute said its economical and urban-friendly technology can help design a safer and more efficient wireless power supply railway infrastructure.
In May, South Korea's wireless charging system for railways was proposed at an online meeting to establish international standards. South Korea has proposed an oval coil method. France, Italy, Germany, China, Japan and South Korea are members of an ad-hoc group at the International Electrotechnical Commission (IEC), which prepares and publishes international standards for electrotechnology.
The IEC ad-hoc group deals with the interoperability and safety of a dynamic wireless power transfer (WPT) system for railways. Cordless charging uses magnetic waves. There is no risk of electric shock, and WPT can reduce tunnel construction costs and fine dust generation. It is possible to freely select the location of stations and increase the length of routes and battery usage time, and reduce waiting time for charging.
The efficiency of power transfer is closely related to primary and secondary coils, their sizes, materials as well as distance. The proper selection and positioning of transmission and receiver coils have a major influence on the efficiency of power transmission. South Korea has stepped up efforts to establish some international standards for a charging system that enables wireless power transmission while an electric vehicle is stopping or running.
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