Innovative Lightweight Technologies Using Power Electronics on Shinkansen High-Speed Electric Multiple Units

Document Type

Journal Article

Publication Date


Subject Area

mode - rail


Tractive forces, Traction forces, Traction control, Tokaido Shinkansen, Thyristors, Technological innovations, Power electronics, Permanent magnets, Japan, High speed trains, High speed rail, High speed ground transportation, Electric multiple unit cars, Axle loads, Advanced technology


In 1964, Japan’s Tokaido Shinkansen (bullet train) line was the world’s first commercial-service, high-speed railway operating at more than 200 km/h. Since then, the Tokaido Shinkansen has demonstrated itself as a successful business and technological advancement. Historically, the Japanese high-speed train system, the Shinkansen, has employed a power-distributed system, an electric multiple-unit (EMU) system, with many advantages such as low axle load and good traction and braking performance. High-speed EMUs take advantage of technological innovations such as electronic technology. An innovative alternating current (AC) drive system, comprising a power converter with a gate turn-off thyristor and AC asynchronous motors, brought a high-performance and lightweight traction system to high-speed EMUs in the 1990s. In EMUs, traction system equipment can be distributed over a train set, and tractive axles throughout the train set can obtain required tractive force without putting a heavy load on the axle. Thus, maximum axle load is reduced, and a lightweight, high-performance train results. Furthermore, recent innovations, such as low switching loss power devices and high-power permanent magnets, have improved AC drive systems of high-speed EMUs of the 21st century. Features and advantages of high-speed EMU systems on the Shinkansen are described, as are recent technological innovations that have given birth to lightweight traction systems, such as the permanent magnet synchronous traction motor and power converters with train–draft-cooling systems. Environmentally friendly aspects of these innovative EMUs are introduced as well.