Determination of thyristor reverse recovery current parameters

This paper describes a method of determination of reverse recovery current parameters of the thyristor turnoff model, namely, the peak reverse recovery current and its decay time constant. The parameters are determined from a set of recovered charge curves, and another set of reverse energy loss curves, usually given in the manufacturer´s data sheet so that the curves may be fitted over a wide range of di/dt at zero current and peak forward thyristor current IF, just before its current reversal. In the parameter extraction, the storage time and the ratio of fall time to storage time were assumed to be functions of di/dt and IF. For various thyristors, the extracted parameters fit both sets of the above-mentioned curves within an error of 8% over a 1:100 ratio of di/dt at zero current and over a 1:4 ratio of IF.