Development and Research of Heavy Pulse Current LTT Switches

The results of research of 100 kA pulse current switches built on light triggered thyristors (LTTs) are presented. Transients in a semiconductor switch are analyzed at a capacitor discharge on an inductor and in a pulse forming network (PFN), which incorporates an inductor and crowbar diodes. Maximal currents for a semiconductor structure, at which thermo-generation peaks appear on oscillograms of forward voltage drop, have been determined. The LTT switch-ON process has been investigated and the need for application of speedup $R$ -$C$ circuits for a fast and stable transition of the LTT semiconductor structure to the conducting state has been shown. Transients at reverse recovery of LTTs in a discharge circuit with an inductor have been analyzed, and the snubbers providing suppression of pulse overvoltages and survivability of semiconductors have been chosen. For PFN, the current switching into the crowbar diodes and pulse overvoltage generation at a reverse recovery of LTTs has been analyzed, and the snubbers for suppression of these overvoltages have been chosen. The results of testing performed at a pulse current up to 100 kA confirm the validity of the accepted technical solutions.