SEOUL – The state-run rail research organization of South Korea has transferred core technologies to domestic companies to commercialize a wireless power system for the light rail. Part design technology, which wirelessly transmit power to the light rail, and the application of wireless power can help design a safer and more efficient wireless power rail infrastructure.
The Korea Railroad Research Institute (KRRI) announced that 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, stores and uses collected energy, and high-capacity capacitor technology for high frequencies.
The institute carried out a 40,000-kilometer (24,850-mile) test on its test line in Gyeongsan to ensure the stable operation of its wireless power system and verify the performance and efficiency of the technology by putting implementing a power of 1 MW, the largest capacity in the world. The introduction of wireless power technology in the 200m throttle section eliminates the need for long high pressure cables running along the track.
While existing systems expose high-voltage wires and bring out wires installed on walls or topsides, KRRI said its wireless power lines are covered with insulating covers and can be installed or buried on the ground, improving considerably safety and urban aesthetics. “The power supply paradigm is changing with wireless technology,” KRRI chairman Han Seok-youn said in an Oct. 20 statement.
The institute said its cost-effective, city-friendly technology can help design a safer and more efficient wireless power supply rail infrastructure.
In May, South Korea’s wireless charging system for railways was proposed in an online meeting to set international standards. South Korea proposed an oval coil method. France, Italy, Germany, China, Japan and South Korea are members of an ad hoc group within the International Electrotechnical Commission (IEC), which prepares and publishes international standards for the electrical engineering.
The IEC ad hoc group deals with the interoperability and security of a dynamic wireless energy transfer (WPT) system for railways. Wireless charging uses magnetic waves. There is no risk of electric shock and the WPT can reduce the cost of tunnel construction and the generation of fine dust. It is possible to freely choose the location of the stations and to increase the length of the routes and the battery usage time, and to reduce the waiting time for charging.
The efficiency of power transfer is closely related to the primary and secondary coils, their sizes, materials and distance. The proper selection and positioning of the transmit and receive coils has a major influence on the efficiency of power transmission. South Korea has stepped up efforts to set international standards for a charging system that enables wireless power transmission while an electric vehicle is stopping or moving.