Determination of thyristor reverse recovery current parameters

The authors describe 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 I_F , 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 I_F. 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 I _F