Switching characteristics of 45-A double-interdigitated GTO thyristors

This work presents the turn-off, turn-on and high-frequency switching characteristics of 45-A 1500-V double-interdigitated GTO switches. The devices possess the highest value of the peak interruptable anode current ever reported in the open literature for 4 × 4 mm area thyristors packed into TO-220 cases. The dynamic evaluation of devices was performed under resistive-inductive load conditions, i.e., close to those encountered in practical circuits employing GTO thyristors. The performed investigations have shown that the novel type of GTOs exhibit the best overall switching characteristics ever presented for this class of GTO switches (identical area and case). The devices performed well under high current and voltage conditions. Even the worst recorded data at higher turn-on and turn-off gains show that the developed GTOs behave as fast commutation devices consuming low input (gate) energy. It was demonstrated that fast turn-off is by no means incompatible with excellent turn-on sensitivity. A remarkable feature of devices consists in a built-in self-protection capability against electrothermal failure during gated turn-off. This unique feature enables the GTOs both to switch large amounts of load current and to safely operate at high commutation frequencies (hundred of kHz) under heavy load conditions.