Integrated gate-commutated thyristors (IGCT)

All Hitachi Energy IGCTs (Integrated Gate-Commutated Thyristors) are press-pack devices. They are pressed with a relatively high force onto heat-sinks which also serve as electrical contacts to the power terminals.

The IGCT's turn-on/off control unit is an integral element of the component. It only requires an external power supply and its control functions are conveniently accessed through optical fiber connections. The device's control power consumption typically ranges from 10 - 100 W.

The IGCT is optimized for low conduction losses. Its typical turn-on/off switching frequency is in the range of 500 hertz. However, in contrast to the GTO, the upper switching frequency is only limited by operating thermal losses and the system's ability to remove this heat. This feature, in conjunction with the device's fast transition between on and off state, enables short on-off pulse bursts with switching frequencies of up to 40 kHz.

IGCTs require a turn-on protective network (in essence an inductor) to limit the rate of current rise. However, in contrast to the GTO, the turn-off protection network is optional. It can be omitted at the price of a somewhat reduced turn-off current capability.