Turn-On and Turn-Off Characteristics of a 4.5-kV 3000-A Gate Turn-Off Thyristor

A 4.5-kV 3000-A gate turn-off (GTO) thyristor has been developed for use in high-power motor drive control equipment such as inverters and choppers. The high gate turn-off current of 3000 A is achieved by decreasing the variation of on-state voltages as well as turn-off times between segments which compose the GTO thyristor. This idea is supported by observation of infrared radiation during the turn-off process in the parallel operation of two segments with different on-state voltages or turn-off times. The parallel operation behavior is well simulated by a two-dimensional numerical simulation. Such design considerations and electrical characteristics of the newly developed high-power GTO thyristor are described. The device has a forward blocking capability of 4.5 kV, a maximum gate turn-off current of 3000 A, on-state voltage of 3.0 V at 3000 A, turn-on time of 10 ¿s, and turn-off time of 25 ¿s.