Mitsubishi Electric delivers world's first SiC auxiliary power supply systems for railcars

JAPAN: Mitsubishi Electric Corp. has commercialized and delivered railcar auxiliary power supply systems that incorporate the world's first silicon carbide (SiC) power modules for actual use in operating trains. Systems now being installed for test operation in new Type 1000 railcars of Tokyo Metro's Ginza Line subway are scheduled to enter commercial operation in June.

Auxiliary power supply systems provide electricity to air conditioners and lighting inside railcars. Compared to Mitsubishi Electric's existing system incorporating silicon power modules, the new system achieves 30 percent less power loss, is 20 percent smaller and 15 percent lighter. It also reduces transformer noise by 4dB due to a 35 percent improvement in the distortion rate of output voltage waveforms.

Compared to Si, SiC helps to reduce size and weight through lowered power loss and higher energy efficiency, as well as smaller power module radiators. Mitsubishi Electric has developed a variety of SiC power module applications, including the world's first large-voltage SiC railcar inverters for DC600V/750V power lines, which were launched in October 2011 and incorporated in Tokyo Metro's Ginza Line Type 01 railcars in February 2012. Also, SiC railcar inverters developed for DC1500V power lines were launched in November 2012 and installed in Tokyo Metro's Tozai Line Type 15000 railcars beginning in January 2013.

The new SiC auxiliary power supply system incorporate technologies Mitsubishi Electric developed for SiC inverters.