Instantaneous temperature rise in thyristors under invertor and chopper operating conditions

The paper presents a method for calculating the instantaneous values of temperature rise in a semiconductor thyristor due to the power dissipation in the turn-on, intermediate and turnoff conduction parts. The method is general, so that different operating conditions and thyristor characteristics can be considered. In the examples, the maximum instantaneous and average hot-spot temperatures are calculated for repetitive-rectangular current-waveform operation with different duty cycles and frequencies. It is shown that, by making the calculations in a particular order, the computation time can be reduced considerably.