Switching behaviour of a pulse-commutated GTO

The operation of an asymmetric (anode shorted) GTO is described theoretically and analysed experimentally. The interrelation between the turn-off losses and the turn-off time with the anode current, and the point of time where the negative gate voltage is applied, is presented. The influences of the snubber and gating circuit are also considered. It is shown that the anode shorted GTO can be operated as an ultra-fast thyristor with current-impulse commutation without a snubber, reducing the turn-off losses of the device to almost one half. The turn-off delay times are also reduced, and no minimum on and off-time is required