Overvoltage protection :

To protect the power devices against all sources of voltage transients, protective elements and circuits like snubber circuits, nonlinear source suppressors and crowbar circuits

1)Snubber circuit dv/dt suppression :

i)Design of snubber network for DC circuit

ii)Snubber design for AC circuit

2) Non-linear surge suppressors

i)varistors(voltage dependent resistor or metal oxide varistor)

ii)Selenium surge suppressors

iii)Avalanche diodes :

3)Crowbar Circuits

Practical overvoltage protection in naturally commutated circuits :

In simple application circuits , it is possible for one voltage suppression circuit to cope with all the possible transient conditions. However in the complicated applications number of suppressors are included to optimize the overall system.

Overvoltage protection in forced- commutated circuits :