Silicon carbide, moving towards a more sustainable train

Wednesday, 27 January 2021 09:34
Silicon carbide, moving towards a more sustainable train

More Sustainable Rail Transport by using Silicon Carbide.

Full Silicon-carbide based traction converter

The ongoing search for new, more efficient technological solutions which have less of an impact on the environment prompted CAF Power & Automation, the Gipuzkoa-based railway systems manufacturing company, and the IKERLAN technology centre, in collaboration with EUSKOTREN, to develop a cutting-edge electric traction system based exclusively on Silicon Carbide (SiC) technology. Said system provides as much as 15% energy savings, depending on the traction system performance and infrastructure conditions.

The traction converter is a fundamental component when it comes to rail vehicle operation, converting electrical energy into the mechanical energy required to move a train. This state-of-the-art "Full SiC" traction solution, consisting of only Silicon Carbide (SiC) semi-conductors, loses 70% less energy and is 25% smaller and lighter.

This technology also improves the efficiency of other traction chain components such as the engines, thereby optimising the energy efficiency of the entire system. EUSKOTREN, the Basque public transport service company, takes part in this project by installing this state-of-the-art "Full SiC" traction system on its vehicles that will be providing commercial service for the next two years.

Reducing environmental impact

As this system reduces weight, volume and noise, it marks a major breakthrough in terms of reducing the impact on the environment. Lesser energy consumption means less CO2 emissions by the system.Not only this but passengers also benefit from improved quality and comfort as the trains are quieter.

"CAF Power & Automation is committed to developing new technology that is in balance with both our society and the environment. Having set long-term goals and setting our sights on future generations, we strive to improve quality of life, providing passengers with more comfortable and sustainable rail transport" says Iñigo Balda, the Managing Director of CAF Power & Automation. “The technology we have developed in the Shift2Rail innovation programme has allowed us to contribute to the future of European transport in a big way", he concludes.

Technological benefits of Silicon carbide over silicon

The main benefits of using silicon carbide (SiC) rather than silicon (Si) are as follows:

- A significant reduction (70%) of the power losses in the module itself.

- The system operates at high temperatures. While the Si limit is approximately 150°C, SiC can withstand temperatures of up to 400°C.

- High-speed switching devices for high-current applications, such as MOSFETs, which are used on this new converter, can be produced using this material (SiC).

- Rapid heat dissipation as SiC has three times more conductivity than silicon.

Basque cutting edge technology development

As part of the European Horizon2020 project, CAF Power & Automation has been developing and producing silicon carbide technology-based equipment for a variety of applications for several years. In collaboration with its technological partner, IKERLAN, it has seen very significant results since 2015 in terms of volume and weight reduction, and gradual progress in terms of traction converter losses, having now reached 70%.

The current converter marks the definitive evolution of the previous prototype, a hybrid system that was developed in 2018. The prototype was equipped with a Silicon (Si) IGBT inverter and Silicon Carbide (SiC) diodes. This marks a cutting-edge solution in Spain which was the first to be fitted on a 1500 Vdc vehicle providing commercial service in Europe, operated by EUSKOTREN.

No problems have arisen since it was set into commercial service.