High di/dt switching with thyristors

Two types of involute-structured SCRs, one with the amplifying gate shorted to the pilot gate (shorted devices), and the other with a normal gate arrangement (unshortened devices), were tested as closing switches in a PFN (pulse forming network). The shorted devices were able to switch larger anode currents at higher values of di/dt of the shorted devices. All energy losses in the shorted thyristors were less than the losses in the unshorted ones. The gate current amplitude had a strong direct relationship to the anode di/dt of the shorted devices. There seemed to be a very weak, if any, correlation between the gate current amplitude and the unshorted device di/dt. The gate pulse width has no measurable effect on the switching parameters. The results indicate that for high-current, narrow-pulse switching, the amplifying gate has a detrimental effect on the thyristor performance.<<ETX>>