Crowbar Scheme Based on Plasma Motion for Pulsed Power Applications

A new crowbar scheme has been devised and implemented for fast and slow capacitor banks of time period 27 and 330 μs, respectively. In this scheme, a plasma motion-based rail spark gap has been modified to incorporate another crowbar electrode at the end of rail electrodes. The discharge plasma generated and accelerated by self-generated magnetic field in modified main rail gap switch is used to close the additional crowbar switch at a predefined time. The feasibility of this scheme has been demonstrated by diverting the main bank current to crowbar resistor at different times, using different effective electrode lengths. The average velocity of moving plasma has been calculated using the delay in the start of crowbar current from load current along with effective electrode length. The measured plasma velocity for slow bank has been found to be in close agreement with theoretical estimation.