High-speed power thyristors with excellent switching and load characteristics

A new generation of high-speed power thyristors is being developed, with standard PNPN structure in stud configuration (three diameters 18-24-32 mm with current rating 50-200 A) and in pellet configuration (three diameters 32-40-50 mm with current rating 200-800 A). Branching the control electrode and the internal amplification of the signal raise the safe maximum di/dt and thus improve the load characteristics, but only at frequencies above 1.5 kHz and correspondingly high switching speeds with low turn-on losses. The main design features are in involute control electrode and mesa positioning of the amplifying control electrode, combined with 20 micro m thick Al metallization of cathode and p-base. Design and performance calculations are based on known relations for exponential current rise, power losses, and temperature rise in accordance with the equivalent circuit. These TB and BK thyristors will completely replace existing TCh, TChI, TB devices.