Study on Output Characteristics of High Repetitive Frequency Nanosecond Pulse Generator Based on the Inductor-Isolation Avalanche Transistor Marx Circuits

Abstract

The production efficiency of active species will be dramatically increased with higher pulse repetitive rate and voltage amplitude in applications driven by the repetitive nanosecond pulses, such as the atmospheric pressure plasma jet generation and plasma sterilization. Marx circuits based on the avalanche transistors is capable of generating pulses with extremely short width (down to several nanoseconds or picoseconds) and high repetitive frequency (up to MHz), suitable for the plasma generation. Traditional avalanche transistor Marx circuits are constructed on the resistor-isolation topology. Previous studies showed that single Marx circuit is capable of generating pulses with about several kV and 10kHz repetitive rate on a resistive load. However, the achievable repetitive rate of the resistor-isolation topology is limited by the RC time constant and the output voltage amplitude will decrease with smaller resistance due to the weaker pulse-isolation-effect in the Marx erection phase. Meanwhile, the total energy efficiency is unavoidable low due to the energy loss in resistors, mainly in the charging phase. In this paper, the inductor-isolation avalanche transistor Marx circuit was designed for efficiently improving the repetitive output capability and total energy efficiency. The influential factors on the output performance were studied including inductance of isolation inductors, number of stages of Marx circuit and capacitance of main capacitor. Continuous output operation mode and burst output operation mode were also designed for various applications.