"I am convinced that we will find a solution quite soon," says ABBs SiC project leader Per Skytt.
All Per Skytt is prepared to say is that the problem has to do with the material and component processing. When the chips were tested in one of ABB's test beds, the developers realised that diode losses increased with time. According to Elektroniktidningen, hydrogen atom diffusion in the material has been identified as the cause of its deterioration of properties.
In order to solve the problem developers have had to re-examine the fundamental properties of the material.
They are also looking at decreasing process variations. Diodes must not vary more than ten per cent, or they cannot be used in parallel.
"We have diode modules which can handle 400A and 2,5-5kV."
ABB has spent ten years and an undisclosed amount of money on research into silicon carbide. However, Elektroniktidningen wonders for how long the company can go on investing in this area without producing commercially viable products.
Gittan Cedervall