Research Of A Microsecond-range Quasi-square Pulse Generator Based On Fractional-turn Ratio Saturable Pulse Transformer And Marx Generator

Pulsed power technology has found its applications in a number of fields,such as agriculture,industry,environmental protection,medical science,bioelectronics,and etc.Defense and industrial applications stimulated intense interests in the area of pulse power technology towards the system with high power,high repetition rate,solid state characteristics,and compact structure.Traditional solid-state pulse generator usually uses cascaded-type voltage circuit with solid-state switch such as insulated gate bipolar transistors?IGBTs?.To avoid series and parallel connection of semiconductor switch such as IGBT,an all-solid-state microsecond-range quasi-square pulse generator based on a fractional-turn ratio saturable pulse transformer?FRSPT?and Marx generator is proposed in this paper.Experimental results show that this generator is able to output a quasi-square pulse with short leading and trailing edge and high quality and fixed flat top,while its repetition rate ability is left to be further researched.The main work and results of this publication are listed below:1.Research of the FRSPT.?1?Analysis and test of the magnetic material used to wind the transformer.The relative permeability of the magnetic material is teated in the condition of low voltage and weak current to analyze the response ability under different drive signal.?2?Make certain of the number of the magnetic cores,the winding numbers and the structure of the FRSPT according to the required index parameters.And then the electrical parameters of this FRSPT are calculated based on the structure.?3?Research of the charging experiment of this FRSPT.Firstly,the stray parameters such as stray resistance and stray inductance in the primary and secondary windings of the FRSPT is analyzed by using the Pspice simulation software;then,the saturated inductance of the secondary winding of the FRSPT is calculated through discharging from FRSPT to a capacitor.It can be finally concluded that this generator is suitable to output a quasi-square pulse.2.Construction of the Marx generator based on FRSPT.?1?The principle and flaw of the traditional Marx generator based on gas switches are analyzed,and a new compact Marx generator based on FRSPT which can replace the gas switches is designed.?2?Experimental research of the inductance-isolating-type and high-voltage silicon stack-isolating-type Marx generator.Use the high-voltage silicon stack to replace the isolated inductance and analyze the advantages of this kind of technology.Finally choose the scheme of the high-voltage silicon stack-isolating-type Marx generator based on FRSPT.?3?An outline of the anti-resonance network is given,and the computational formulas of using two or three section anti-resonance network are obtained.Simultaneously,the characteristics of quasi-square pulse forming from two and three section anti-resonance network have been researched.Finally,the application of three-section anti-resonance network in Marx generator has been studied.Experimental results show that the three-section anti-resonance network has the ability of outputting a quasi-square pulse from an LC oscillation waveform of Marx generator.3.Investigation of the microsecond-range quasi-square pulse generator based on FRSPT and Marx generator.?1?The quasi-square pulse generator based on FRSPT and Marx generator is constructed and the structure and its operating principle are presented.Pspice software simulation results show that the Marx generator has a great voltage boosting ability and the output load voltage has the voltage amplitude of 33.6 kV and the pulse width with1.98?s,with a fixed flat top.?2?In the single-trail experiment,with the primary operating voltage varies from200 V to 400 V,the load voltage increases with great consistency.The maximum output voltage is 34 kV.?3?Pack this generator in a polyethene outer barrier,and inflate SF₆ into it to improve its voltage capacity.With the primary operating voltage varies from 400 V to900 V,the load voltage increases with a good consistency.The maximum output voltage is 54.3 kV.?4?The repetition rate experiment results show that the generator can work stably with the repetition rate of 28.5 Hz.With the limitation of the charging power of the energy storage system,the waveform consistency decreases when working for a long time.When the primary operating voltage stays 350 V,a quasi-square pulse can be obtained with the amplitude of 27.4 kV and the pulse width of 1.96?s.?5?The Metal-Oxide Varistor?MOV?and its nonlinear volt-ampere characteristics are introduced.Then an experimental platform is constructed to measure the voltage and current in the MOV chosen in this paper,obtaining a preliminary conclusion:the threshold voltage of the MOV chosen in this paper is 1.5 times of the nominal voltage.Finally,experimental research of the application of MOV in this generator is carried out,leading the conclusion that applying appropriate MOV in this generator will output quasi-sqaure pulse with high quality.