Mitsubishi Electric Delivers 140kVA SiC Auxiliary Power Supply Systems for Railcars

March 25, 2013 by Jeff Shepard

Extending its offering of silicon-carbide (SiC ) based power converters for rail road applications, Mitsubishi Electric Corporation announced today that it has commercialized and delivered railcar auxiliary power supply systems that incorporate the world's first 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.

The new SiC auxiliary power supply system incorporate technologies Mitsubishi Electric originally developed for SiC inverters. The new converters are rated a 600V input and product 140kVa of power divided among 4 output voltages (200Vac, 100Vac, 100Vdc and 24Vdc. These converters are designed for natural convection cooling in the harsh environments encountered by railcars.

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% less power loss, is 20% smaller and 15% lighter. It also reduces transformer noise by 4dB due to a 35% 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.