Decipher Turn-On Voltage Plateau of High-Voltage Integrated Gate Commutated Thyristors

The high-voltage integrated gate commutated thyristor (IGCT, reverse-blocking type) is a suitable device for hybrid line-commutated converters to resist commutation failures. During the turn-on process, a voltage plateau is observed under a high the current rise rate di/dt up to kA/mu s. In order to decipher the mechanism and the potential risk of this phenomenon, this article focuses on the microprocess and influencing factors of the voltage plateau and finds out that the shortage of injected holes depresses the process of discharging space charge region and leads to this phenomenon. Further, the thermal stability and life-long reliability are clarified. This article will be in favor of the research and development of high-voltage IGCT devices both scientifically and technically.