Compound power switch with parallel conducting paths - with thyristor and choke in one path and surge path of FET capacitor and GTO thyristor

摘要

The element consists of a main thyristor (1) in parallel with a series circuit composed of a Gate Turn-off thyristor (T) capacitor (2) and FET (3). The capacitor (2) is charged via a diode (6) by one secondary winding (5) of a trigger pulse transformer. Another secondary winding (4) supplies the antiphase pulse to the main thyristor (1) via a diode (8) and resistor (7). A choke (10) in series with the main thyristor provides a delay in the current shut-off speed. The FET (3) is used to allow the thyristor to fire, as FETs can withstand high currents for short periods, with very small power loss.