Pulsed Voltage Droop Compensation for Solid State Marx Modulator

Solid state Marx type modulators for long flat top pulse application >20 muS have a limitation in that the output voltage will droop as the Marx capacitors are discharged by the pulse current installing suffices capacitance to alleviate the droop limitations for long pulses operation can have significant design, size, and cost implications. A droop compensation technique is desirable for the solid state Marx modulator for most long pulse applications. Droop compensation for capacitor switched modulators called a "bouncer" has been successfully used by Fermi National Laboratory for their long pulse modulators. The "bouncer" configuration however is large, expensive, and inflexible to pulse length and load changes. Other techniques such as the SLAC "mini-Marx" (a second low voltage solid state Marx interlaced with the main Marx) provide discontinuities in the flat top voltage waveform as well as a very complicated control system. Stangenes industries is developing a droop compensation technique, which provides for smooth and flexible pulse voltage waveform droop compensation for the solid state Marx modulator while being small and cost effective. The technique utilizes the modulators existing solid state Marx module configuration and needs no secondary power source or complicated control system. The paper will delineate this unique design of the solid state Marx droop compensator for long pulse operation.