Diode and thyristor turn-off snubbers simulation by KREAN and an easy to use design algorithm

Abstract

RC snubbers must be used for limiting the overvoltages at the diode or thyristor reverse recovery transients. This is true for the application range from line frequency conversion to the output rectifiers in switched-mode DC power supplies. An insight into the mechanism of the turn-off waveforms is obtained by simulations and calculations, and the tradeoffs between overvoltages and losses are presented. An easy-to-use nomogram for the selection of the snubber components is given. A computer program dedicated for power electronic circuit analysis under development, KREAN, is used for the simulations, and is briefly described.<>