Improved snubber network performance by use of diode characterisation techniques

The gate turn-off thyristor (GTO) can be destroyed during turn-off if an excessively high dV/dt is applied across the device. To protect against this failure mechanism, a snubber network is normally used in GTO circuits. The design of such snubber networks has tended to concentrate on the choice of resistor and capacitor values along with the minimisation of snubber inductance by physical layout of the circuit. The circuit designer can utilise standard equations to determine the required values of linear components but the choice of snubber diode is more subjective. This paper deals with the choice of the snubber diode and how this device interacts with linear components of the snubber network