Mitsubishi Electric to Launch Railcar Traction Inverter with All-SiC Power Module

  Mitsubishi Electric to Launch Railcar Traction Inverter with All-SiC Power

            3.3kV, 1,500A inverter suitable for high power trains

Business Wire

TOKYO -- December 24, 2013

Mitsubishi Electric Corporation (TOKYO: 6503) announced today that it has
launched a railcar traction inverter system for 1,500V DC catenaries that
incorporates the world’s first all-silicon carbide (SiC) power modules made
with SiC transistors and SiC diodes. The all-SiC inverter greatly reduces
power loss, size and weight compared to conventional insulated gate bipolar
transistor (IGBT) power modules and hybrid power modules made with Si
transistors and SiC diodes.

Mitsubishi Electric’s large-capacity, all-SiC power modules are expected to
help save power as well as lower the size and weight of equipment used in high
power trains including Japan’s Shinkansen.

The new traction inverter system’s switching loss is approximately 55% less
than Mitsubishi Electric’s conventional inverter system incorporating IGBT
power modules. The new system also increases regenerated energy through the
use of regenerative brakes in all speed ranges. Thanks to these solutions,
total energy consumption of railcar systems, including their motors, is
reduced by about 30% compared to conventional systems.

Size and weight are reduced by about 65% compared to conventional inverter
systems with IGBT power modules and about 30% compared to existing hybrid
inverter systems with SiC diodes.

The number of components is reduced by integrating SiC transistors and diodes
into one package per inverter circuit phase.

Energy saving in total railway systems is further enhanced by effectively
transferring regenerated electric power from the railcar to stations to be
equipped with Station energy-saving inverters (S-EIV).

Main specifications of new traction inverter system

Input voltage:          1,500V DC
Main circuit system:       Two-level PWM inverter with regenerative brakes
Control system:            Four traction motors with 180kW, parallel control
Cooling system:            Self-cooling


The dielectric strength voltage of SiC is about 10 times greater than that of
Si. SiC devices can operate at higher temperatures than Si devices because of
the high breakdown voltage and low conduction loss of thinner semiconductors.
Unlike the ongoing development of SiC diodes, development of SiC transistors
has proven difficult due to problems with crystal preparation, which requires
highly advanced insulation and package technologies capable of withstanding
high temperatures. Mitsubishi Electric’s R&D and production units combined
their respective expertise in semiconductor development and manufacturing to
successfully develop the new large-capacity, all-SiC power module with MOS-FET
for use in the world’s first all-SiC railcar traction inverter.

Development of SiC power modules has been partially supported by Japan’s New
Energy and Industrial Technology Development Organization (NEDO).

Mitsubishi Electric’s previous record of SiC inverter development

In October 2011, Mitsubishi Electric produced a railcar traction inverter for
600V DC, 750V catenaries incorporating the world’s first large-capacity hybrid
SiC power modules. With help from Tokyo Metro Co., Ltd., the system was
field-tested in commercial railcars operating on its Ginza Line subway,
demonstrating 38.6% energy reduction comparing to conventional inverters in
other railcars operating on the same line.

About Mitsubishi Electric Corporation

With over 90 years of experience in providing reliable, high-quality products,
Mitsubishi Electric Corporation (TOKYO: 6503) is a recognized world leader in
the manufacture, marketing and sales of electrical and electronic equipment
used in information processing and communications, space development and
satellite communications, consumer electronics, industrial technology, energy,
transportation and building equipment. Embracing the spirit of its corporate
statement, Changes for the Better, and its environmental statement, Eco
Changes, Mitsubishi Electric endeavors to be a global, leading green company,
enriching society with technology. The company recorded consolidated group
sales of 3,567.1 billion yen (US$ 37.9 billion*) in the fiscal year ended
March 31, 2013. For more information visit

*At an exchange rate of 94 yen to the US dollar, the rate given by the Tokyo
Foreign Exchange Market on March 31, 2013


Customer Inquiries
Mitsubishi Electric Corporation
Railway Transportation
Public Utility Systems Group
Media Inquiries
Mitsubishi Electric Corporation
Katsunobu Muroi, +81-3-3218-2346
Public Relations Division
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