Power Electronics in the 9 MJ EM Range Gun System

The Center for Electromechanics at the University of Texas at Austin (CEM-UT) is developing an open range demonstrator electromagnetic (EM) gun system with specific size and mass constraints. The design being pursued includes a single phase full bridge rectifier and inverter to accomplish a self generated field excitation and regenerative field energy recovery. The peak power of the excitation system is over 600 MW, performing for single second operations at a repetition rate of once every 20 s over 3 min. The design also includes a solid-state thyristor switch for firing the railgun. This switch closes for one half cycle of ac current, reaching over 3,000,000 A and lasting up to 6 ms. The open circuit rms voltage is 4.2 kV at 125 Hz. These power electronics subsystems have been designed to be compact and lightweight. This paper presents the design parameters, packaging, and control strategies employed.