High energy pulse modulator for microwave tube applications

This paper describes the development of a 140 kV 40 A long pulse (100 μs to 1.6 ms) modulator that combines 8 IGBT plus capacitor bank modules via a 1:93 step up transformer to a klystron load. The modulator is integrated to a 1.5 kV DC supply which uses its digital controller to provide PRF, pulse width, and pulse timing information. A GTO crowbar and pulse transformer reset modulator, named Remag, is integrated into the system. The paper will describe the overall system concept and realisation; with detailed descriptions of the GTO crowbar, the module, pulse transformer reset system, and the pulse transformer. Voltage monitoring and the integration with the DC supply will also be discussed. Construction methods and test results from the system will also be outlined.