Non-linear capacitors in snubber circuits for GTO-thyristors

Applications with GTO (gate turn-off) thyristors have until now required snubber circuits, at least for turn-off. At high switching frequencies there are conflicting design criteria for the snubber capacitor, concerning losses versus timing conditions. To improve this situation the authors use nonlinear capacitors. They demonstrate the features of snubber circuits with nonlinear capacitors by evaluating experimental results obtained from 50 A and 90 A GTO thyristors