Abstract:
Background With the growing demand for fast-rising high-voltage pulses in industrial, medical, and plasma-related applications, solid-state Marx generators are increasingly used as pulse sources. However, the limited switching performance of semiconductor devices and constraints of circuit topology pose significant challenges for the design of solid-state Marx generators capable of producing very steep rising time.
Purpose This study investigates the factors that determine the rise time of solid-state Marx generators and, on this basis, develops a generator that meets the performance requirements for fast-rising pulses.
Methods A discharge-circuit model of a semiconductor-switched solid-state Marx generator was established, and simulations of parasitic elements were carried out in LTspice to identify their influence on the pulse rise time. In addition, the characteristic impedance of a coaxial output structure was incorporated into the simulations. Guided by these results, a solid-state Marx generator using dual parallel switching paths and a coaxial output structure was designed.
Results Simulation results indicate that the series parasitic inductance of the circuit, the gate-drive resistance, and the Miller capacitance of the switches have the greatest impact on the rise time. By selecting appropriate MOSFETs and choosing a coaxial inner conductor with a characteristic impedance of 177.4 Ω for a 200 Ω load, a coaxial solid-state Marx generator was realized that delivers 10 kV/50 A pulses with a measured rise time of 7.6 ns.
Conclusions Based on this analysis and design, a high-performance high-voltage pulse generator has been developed. The results provide a useful reference for further shortening the rise time of solid-state Marx generators, broadening their application range, and promoting their use as alternatives to conventional gas-switch Marx generators.
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