Formula E racing team provided with ROHM SiC power modules

The inverter for season four features embedded full SiC Power module, making it 43% smaller and 6kg lighter than the inverter for season two. ROHM will continue making technological advancement in power devices, contributing to the development of society.

Inverter comparison
Formula E is an all-electric-powered FIA (Fédération Internationale de l'Automobile) championship that began in 2014. The series has expanded to cities around the world which has to date included cities such as Hong Kong, Berlin and New York. By not using fossil fuels Formula E champions a clean environmental approach.

The key to victory in this racing series for the drivers is to use power as efficiently as possible by getting the maximum performance out of the stored energy. The advancement in Formula E technology is expected to filter through to developments in general-use electric vehicles. Although this motorsports event is still in its infancy, it already enjoys the participation of automotive manufacturers from around the world.

Major automobile manufacturers including those from Japan have also declared their intention to take part in Formula E. For many years, ROHM has provided a highly varied lineup of products designed for automotive use. These include power supply ICs, various control ICs, along with discrete products such as power devices, current detection shunt resistors.

ROHM is pushing forward with the latest development of SiC power devices, which are expected to realise dramatic loss reductions compared to conventional Si (silicon) power devices. These power devices will be used more and more on Electric Vehicle (EV) motors and inverters.

Statements
Franck Baldet, CTO, VENTURI Formula E Team said: “The Formula E is the only motorsports event for testing the latest technology in next-gen electric vehicles. We are extremely happy about our technical partnership with ROHM in the area of power management, which is the foremost key to the Formula E race. For season 4, by adopting a full SiC power module, we were able to bring to reality a lightweight inverter that requires only a minimum amount of space. By using the latest technology, I expect that we will be able to dramatically reduce our lap times, and I hope that we can continue to move forward with revolutions in technology through our partnership with ROHM.”

Kazuhide Ino, Group General Manager of Power Device Production Headquarters, ROHM said: “ROHM has been providing products for many years for today’s constantly evolving automobiles, with quality as our main advantage. This is currently a field in which we would like to give our special attention; and semiconductor devices are certain to play a crucial role in recent hybrid and electric automobiles. The SiC power device that we are providing for the Formula E racing car is one example. We provided SiC-SBDs in season 3 last year (2016–2017), but this year we provide full SiC power modules that combine SiC SBD and SiC MOSFET. These modules will contribute to improve vehicle performance. I hope that we can continue to contribute to society through the efficient conversion of energy in a wide range of industries and fields, starting with electric vehicles.”

The advantage of using SiC products
The SiC power module used in the inverter of the VENTURI Formula E team racing car achieves a large power throughput. This is due to the development of a new package with an improved internal module structure, as well as optimised thermal management.

Compared to conventional IGBT modules with similar current ratings, this module reduces switching losses by 75% (at a chip temperature of 150°C). This contributes to the energy efficiency for the whole application. Also, the high frequency drive facilitates the use of smaller peripheral components.

This, as well as the effect of reductions in switching losses contributes to a more compact cooling system. By using this full SiC power module in the inverter section (the powertrain core), the inverter is 43% smaller and 6kg lighter than the version used in season two. Even compared to the previous inverter used in season three, it is 30% smaller and 4kg lighter.