Characterization of high power thyristors

As commercial applications for compact, efficient high voltage pulsed power systems expand, the need for high power, fast turn-on maintenance-free switches also increases. To meet this combination of requirements, there is a trend toward utilizing more solid state switches in high voltage systems. Of all the solid state devices commercially available, gate-triggered thyristors handle the highest power levels by a wide margin. They are, therefore, of considerable interest to very high power electronic systems such as accelerators and plasma generators. Their primary limitation, the rate of current rise (di/dt), has restricted their use to relatively slow pulse applications when operated within manufacturers´ recommended ranges. However, since the mid-1980s it has been demonstrated that the turn-on speed of large, interdigitated thyristors could be substantially increased by bypassing the amplifying gate and applying a high current pulse directly to the main gate. With this arrangement, turn-on rates up to 100 kA//spl mu/s were measured for single-shot tests. The present characterization tests extend these data for high current repetition rate operation. Turn-on rates for varying conditions of energy per pulse, peak current and pulse repetition rate have been measured. Triggering tests over a range of voltages and current levels for both amplifying and main gate triggering have been carried out. This report presents data from these tests and includes an outline of limiting conditions for discrete operating ranges.