Railgun modeling with the P-Spice code

Abstract

Starting from the conventional modeling of the railgun as an electrical circuit coupled to a mechanical system, we have developed our own model including detailed behavior of aspects of electrical components such as non linearity of the resistance and charge accumulated in semiconductors. This permits an accurate modeling of sensitive devices like switching semiconductor diodes (crowbar). In a second approach, we incorporated the velocity skin effect by using a one dimensional approximation. The results are compared to measurements obtained on a DES (Distributed Energy Storage) capacitor driven railgun (PRESTUDY PEGASUS) with a stored energy of 2.8 MJ and a 50 mm round bore. The calculated currents and velocity are in good agreement with the measurements. Voltages and energy distribution in different parts of the circuit are also compared, to obtain information of the loss mechanism in our railgun. Fault analysis of the switching modules is also described.