Circuit model for parameter study of Marx generators on megajoule machines

Sandia National Laboratories (SNL) is planning to redesign the pulsed power driver on Z, including the Marx generators, the intermediate-store water capacitors, the laser triggered switches and the pulse-forming lines to increase the energy delivered to a Z-pinch load. The present Marx system consists of 36 generators that store over 11 MJ of energy. Each generator contains sixty 1.30 /spl mu/F capacitors that are charged in bipolar fashion to 95 kV. The system erects to 5.7 MV when switched, and stores 366 kJ of energy. The 60-capacitors are configured as 12-capacitors to a row and 5-rows to a generator. A circuit model has been developed using MICROCAP to model one of the 36-Marx generators. The model contains the capacitors, inter-stage switches, ground resistors, trigger resistors, and the connection and internal inductance, capacitance, and resistance associated with the generator components. The paper describes the approach used to develop the model, presents the model, validates the model by comparing output to measured data, and shows how parasitic coupling can affect generator performance.