Power Electronics for Medium Voltage Applications

Due to the high band gap and the high breakdown field strength of silicon carbide (SiC), power semiconductors with particularly high reverse voltages, typically higher than 10kV, can be manufactured with this material. These components open up new areas of application for medium-voltage power electronics. Compared to circuits with Si-IGBTs connected in series, switching frequencies can be increased by a factor of 10. This is due to the low switching losses and low conduction losses of the components. This considerably reduces the switching effort and the size of inductive components such as chokes coils and transformers.

In the medium voltage range, SiC transistors can be used to build compact and efficient power electronic converters with and without galvanic isolation. The high possible frequencies open up new possibilities, e.g. for circuits with medium-frequency transformers or for the compensation of harmonics up to the kHz range. In the future, single-phase and three-phase inverters can be operated directly at medium voltage without a transformer, which will open up new application possibilities for renewable energy and power grids in particular. SiC transistors also play an important role in mobile applications such as railways when it comes to saving weight and installation space.