In recent years, hydrogen energy has attracted a lot of attention as a source of renewable energy. As a promising technology that uses hydrogen energy, fuel cells are now being developed to provide a clean energy source whose only by-products are water and unused air. The RTRI is therefore promoting research and development towards using fuel cells as a source of power to drive rolling stock, and has developed a fuel cell system with a capacity of 100 kW (the minimum output required to power a railway car). This system, which automatically changes its output according to the load, is composed of eight stacks (each with a rated capacity of 19 kW) plus devices required for operating the fuel cells. The RTRI also manufactured a prototype high-pressure hydrogen tank system and an inverter unit suitable to the output of the fuel cells, and developed a test car with these systems, which is driven by a fuel-cell power source (Fig. 1).
The RTRI implemented a running test of the car at 40 km/h with fuel cells output of 90 kW (Fig. 2) on the test track, and confirmed that the carfs speed can be increased to 105 km/h with the same power on the rolling stock test plant under actual load conditions (Fig. 3). A chopper unit was also connected to the output side of the fuel cell system, and the car was run at 40 km/h with the output voltage of 1,500 V on the test track. The test results confirmed that the fuel cells could change their output according to the load of the car, and the RTRI plans to study the possibility of a hybrid rolling stock system using fuel cells.
Part of this research and development was executed with a subsidy from the Ministry of Land, Infrastructure and Transport.