Fast high-voltage, high-current switching using stacked IGBTs

The development of solid-state switches for pulsed power applications has been of considerable interest since high-power semiconductor devices became available. However, the use of solid-state devices in the pulsed power environment has usually been restricted by device limitations in either their voltage/current ratings or their switching speed. The stacking of fast medium-voltage devices, such as IGBTs, to improve the voltage rating, makes solid-state switches a potential substitute for conventional switches such as hard glass tubes, thyratrons and spark gaps.This paper reports on a comparative study into the performance of commercially available 1.2 kV IGBT devices. It has been found that dual degradation of the drainsource voltage can be observed in most of the devices and the reasons for this have been investigated. Further studies have looked at the performance and operation of a high current switch employing fifty 1.2 kV IGBTs in a stacked configuration. Switching times of a few
tens of nanoseconds have been measured for a 10 kV charging voltage switched into a 25 R input impedance Blumlein pulse generator.