Rotating machines-power supplies for the next generation of EM accelerators

The next generation of electromagnetic launchers (EMLs) will require compact, lightweight power supplies which can generate high-magnitude, repetitive current pulses of a very specific shape. Additionally, a simple, reliable system in which logistic concerns are minimized is required. Rotating machines, in particular compulsators, can meet these needs. The compulsator is a specialized alternator which has been designed to produce a series of high-power pulses. A number of advantages are inherent in the use of these devices for EML applications. In addition to high energy and power density, and the lack of additional power conditioning components, the machines are well-suited for the requirements of an electromagnetic (EM) gun circuit. The compulsator produces an alternating voltage which drives the current pulse through a current zero, achieving the desired pulsewidth. Conceptual designs of compulsator-driven pulsed power systems for use in 18 missions of interest were analyzed. These missions, which are summarized, include a wide variety of projectile masses and launch energies. Power supplies were designed to accommodate five types of launchers for each mission: railguns, coilguns, thermal-electric guns, hybrid guns, and the advanced electric gun. The hybrid gun represents a railgun with a thermal-electric injector and the advanced gun is a hypothetical far-term coilgun. The results of this analysis, including a general description of the compulsator, design assumptions, the methods used to achieve the desired pulse shape,s a discussion of magnetic energy recovery, gyroscopic effects, and scaling information are included