A Modular Over-voltage Trigger Device for Two-electrode Spark-gap Switches

In order to meet the requirement of high repetitive operation of Marx generator, which is normally restricted by the ablation and self-breakdown problems of three-electrode spark-gap switches, a modular over-voltage trigger device for two-electrode spark-gap switches is designed in this paper. The proposed two-electrode spark-gap switches are designed on the basis of an eight-level inductive isolated Marx generator. Numerical simulations and experiments are carried out for a single stage over-voltage trigger device, respectively. The influence of the transformer parameters, pulse width, and peak value of output voltage on the trigger waveform is discussed. Furthermore, the overall simulation model of the Marx-generator triggered using over-voltage triggering method is established. The results show that trigger waveforms with amplitude of 5.8 kV, front edge of 160 ns, and half-width of $1.8 \mu\mathrm{s}$ are achieved for a single stage trigger when the input voltage is 220 V. A programmable SiC MOSFET driver circuit based on FPGA platform is designed and will be used in the following study of the device.