Low weight and size pulse forming unit, switched by a novel high current rate SCR

The 50 kJ pulse forming units (PFU) for the 10 MJ ISL-facility PEGASUS, switched by SCRs, are equipped with 30 /spl mu/H inductors in order to decouple the units inductively for security reasons and to limit the maximum current to 60 kA. This limitation is obliged by the application of thyristors with an admissible maximum current of 90 kA. Due to the novel SCRs, developed by ABB Semiconductors and ISL, with a maximum current of more than 120 kA and a current rate dI/dt higher than 5 kA//spl mu/s, it is feasible to design and build a 50 kJ-PFU without the above mentioned inductor. Thus the weight, size and costs of the 50 kJ-module will decrease drastically. Furthermore, the output current pulse is shorter. So, more flexibility is possible for total current pulses, shaped by several units triggered with different time delays. Besides this, the railgun current after shoot-out is considerably reduced. A novel PFU with its electrical properties due to a railgun application are presented in the paper.