Effect of resistance modification on EML capacitor bank performance

The U.S. Navy is considering the development of an electromagnetic launcher (EML) for surface-fire support and other missions. The Naval Research Laboratory has initiated a program to develop and test materials to achieve these fire rates and lifetimes. The U.S. Naval Research Laboratory has assembled a facility to develop and test materials for the study of barrel lifetime in electromagnetic launchers (EML) for surface-fire support and other missions. The pulsed power system utilizes several modules that can be individually triggered to shape the output current pulse. Each bank module consists of capacitors from General Atomics Electronics Systems. The switching thyristors and crowbar diodes are from ABB. A series inductor is used to limit the peak current, isolate modules from each other, and ensure the current is delivered to the test system. Several launch events have been performed, and the pulsed power systems have operated as intended. The capacitor bank modules were originally designed with minimum output resistance to obtain the maximum L/R decay time into the launcher. Modification of a module to allow for a variable output resistance is highly desirable to modify the output waveform of the bank module system, such as limiting the late-time current. NRL has designed resistance packages that can be easily inserted into a specific bank to modify the damping of the current. The effect of the resistance will be shown at various power levels and the resulting effect on switch action, capacitor voltage reversal, and output current will be demonstrated. Computer modeling of the modifications will also be discussed.