32-Stage Semiconductor-based Marx Modulator with Resonant Charging

For the Pulsed Electric Field treatment of potatoes, a 32-stage Marx modulator has been set up. The Marx modulator is grounded at its center and consists of two stacks of 16 stages each. Its pulse shape is determined by the passive components of its RLC pulse circuit. The generator has been designed for a repetitive operation near one well defined operating point at a stage voltage of around 800 V, and a pulse current up to 500 A. The design features only one active switch per stage and resonant charging via current-compensated chokes. The auxiliary power supply at each stage is powered by the stage voltage. The principle of operation of the generator design has been previously tested in an 8-stage setup. In this paper, selected design details and first test results obtained with the 32-stage generator are presented.