Optimization Design And Performance Simulation Of Gas Switches For FLTD

Fast Linear Transformer Drive(FLTD)can output high power and fast front pulse directly without pulse compression,which greatly reduces the size and economic cost of the pulse device and has broad application prospects in the pulse power technology field.Gas switch is a key component of the FLTD device to achieve energy conversion and transmission.The switch is closed and turned on so that multiple modules are operated in series and parallel,thereby achieving the superposition of pulse voltage and current.Therefore,the gas switch characteristics will directly affect the pulse output performance of the device.Reducing the switch delay and jitter is conducive to the accurate synchronous operation of the module,thereby reducing the leading edge of the output pulse and improving its stable operation ability.In addition,the static parameters,dynamic characteristics,switch life,and repetitive frequency operation ability of the switch are also key parameters affecting the operation performance of the device.Combined with the parameter requirements of gas switch on FLTD device,this paper has completed the optimal design of ±100k V gas switch through theoretical calculation and software simulation,and simulated the relevant performance of the switch by circuit simulation,and mastered the influence of each switch parameter on the output pulse.The main research contents of this article are as follows:First,the conduction mechanism of the gas switch is analyzed,and the flow path of the gas switch is explained by the streamer theory;the structure and working principle of commonly used gas switches are summarized;the structure and working principle of commonly used FLTD gas switches are analyzed,including multi-gap and ultraviolet preinization gas switches.The ultraviolet irradiation during the discharge of the ultraviolet preinization gas spark switch will cause space photoionization and cathode surface ionization,which can reduce the delay and jitter of the switch.This article takes the ultraviolet preinization gas switch as the research object.The FLTD gas switch described in this article features Refers to this type of switch.Secondly,for the optimized design of the FLTD gas switch,the gap distance is calculated in this paper.Considering the switch working voltage and cavity pressure,the main gap of the switch is composed of two gaps with a gap of 10 mm in series,and the air pressure in the switch cavity is 0.5MPa;the effect of electrode structure on the electric field of the switching gap was analyzed by COMSOL software simulation,and the utilization of the electrode is improved;the electric field along the surface of the insulation cylinder was analyzed by COMSOL simulation.The simulation results showed that the groove in the insulation cavity and the addition of an inner insulation cylinder could increase the surface distance,reduce the electric field on the insulating surface and prevent flashover along the surface.In addition,the screen design of the inner insulating tube can prevent the sputtering of electrode ablation;and the mechanical strength of the switch is verified by simulation analysis and theoretical calculation.Designed to meet mechanical strength requirements.Finally,using COMSOL to analyze the electrostatic field before and after the gas switch is triggered,the maximum field strength appears at the fillet corner of the electrode,the coefficient of electric field inequality f is 1.24,the multiple of overvoltage after the switch is 1.79,the switching energy reliable breakdown after triggering;using PSPICE to establish a switch discharge circuit model,simulation analysis of the trigger circuit inductance,isolation capacitor,grounding resistance,protection resistance,preinization isolation capacitor and other parameters on the trigger pulse peak and rising edges Through PSPICE simulation analysis of the influence of loop parameters on pulse output,the basic law of pulse peak and rising edge changes was mastered.Through these simulation analysis,the performance of the switch is verified,and the designed gas switch can achieve the expected goal of the design.