The Internally Commutated Thyristor - A new GCT with integrated turn-off unit

Today, Gate Commutated Thyristors (GCTs) are commonly used for high-power voltage source inverters, due to their superior electrical performance compared to GTOs and HV-IGBTs. However, the gate drive of a GCT is more complex than an IGBT driver and has to be connected closely to the GCT, which implies several constructional disadvantages. The Internally Commutated Thyristor (ICT), a GCT with integrated turn-off unit, enables the use of a simplified and more reliable gate drive. The electrical performance advantages of the GCT are at least maintained, if not improved in some aspects. In this paper, the ICT concept is presented and measurement results using a first prototype are given. The consequences for the gate drive design are discussed and the new device is compared with existing standard GCTs. Improved reliability, electrical performance and usability are key features of the ICT.