Study On The Modularized,Light-Weight,Long-Pulse,and High-Power Modulators And Their Synchronous Synthesis-Related Technologies

High power pulse modulator has found its wide applications in national defense,industry,environmental protection,argriculture,and in biology.At present,high power pulsed generator has some problems such as high charging voltage,breakdowns in transformer and transition sections,self-breakdowns in switches,and so on.Therefore,it is one of the development trends of the pulsed power technology to adopt the technology of simultaneous-synthesis of multiple power modules.Applications in defense and industry have sparked a strong interest in pulse power generators,leading to the development of modularized,light-weight,long pulse and precisely controlled technologies.In the multi-module synchronous-synthesis technique of the high-power modulators,there are several key problems need to be solved: the fist is that the multi-channel synchronous-synthesis of the multiple modules needs the trigger and control system with a very high synchronicity and a low jitter.To employ the control signal and the main switch trigger with an accurate control of ns level is the key difficulty in the trigger control system.The second is that without reducing the output power and other characteristic parameters of the single module,the volumn and weight of the module should be decreased,and its mobility and flexibility should be improved to facilate the maintenance and operation of the single module.The third is to achieve stable,long pulse and repetitive operation of a single module under high power output condition.This thesis is to study the above-mentioned key technologies in the multi-channel synchronous-synthesis of the high-power pulse modulators.The contents and creativities of the present thesis are listed below:1.Aiming at the contradiction between the limited power output capacity of a single pulse modulator and the increasingly high application requirements,a new parallel synchronous-synthesis technical-scheme of the high-power modulators is proposed and studied.The results are very significant for further increasing the output power of the pulse generator and maintaining its long pulse and stable repetitive operation.2.A novel light-weight single module of pulse modulator is proposed and studied.Using the dual-switch modulation technique,which applies fractional-turn ratio saturable pulse transformer charging to a pulse forming line with a low characteristic impedance and also applies an addtional gas shaping switch,to solve the problem of the large saturable inductance and output pulses with fast leading edge when using magnetic switch as the main switch.The dual-switch modulation technique can reduce the charge voltage of the transformer,reduce the insulation pressure and obtain a higher coupling coefficiency of the transformer,so as to make full use of the magnetic core and decrease the volumn and weight of the transformer.Preliminary estimates show that the volumn and weight of a single-module of the high-power generator with the dual-switch technique can be reduced to about 70% of that of the modulator of the conventional modulation technique.3.In view of the obvious dispersion and serious waveform distortion of the conventional single spiral-band coaxial transmission line under a large slow wave coeffficent,a coaxial transmission line with multiple spiral-wires in parallel with large slow wave coeffficent is studied.The theoretical model of the pulse boost and impedance transform based on the transmission line is established,through which the impedance of each transmission line can be calculated accurately,and the maximum theoretical boost coefficient and power transmission efficieny can be obtained.Dispersion analysis,simulation and experiments of the coaxial transmission line with multiple spiral-wires in parallel are carried out.It is proved that the application of the coaxial transmission line with multiple spiral-wires in parallel is an effective way to realize the transmission line with a large slow wave coefficient,transmit long pulse signal and promote the compactness and light-weight characteristics of the high-power modulator.4.Aiming at the requirment of the low jitter of the trigger and control technology for the multi-module synthesis,this paper has designed an all-solid-state trigger based on a fractional-turn ratio saturable pulse transformer and a Marx generator.The time jitter characteristic was analyzed and test experiment has been carried out.A pulse with leading edge of 95.1 ns and amplitude of 41.2 k V can be obtained on a 100 kΩ large power resistive load.And repetition frequency experiments and time jitter analysis were carried on.Under the repetitive frequency mode,the output waveform was stable without obvious fluctuation,and the time jitter of the trigger ranged from 1.92 ns to 3.45 ns.Its technical characteristics are better than those of the electric triggers published in the domestic journals,which lays a solid foundation for its application in parallel synchronous-synthesis technology of the high-power generator.At the same time,in view of the main switch sensitive to the conduction time in the dual-switch modulation technique,a field distortion type triggered main switch is designed.The internal structure and field strength of the switch are optimized by the theoretical calculation and static field simulation,and the main structural parameters of the field distortion type triggered main switch are given finally.5.A low-impedace GW level modulator verification device based on the dual-switch modulation technique and variable impedance transmission line was established,which achieved output peak voltage greater than 60 k V,pulse width of117.5 ns,and repetition frequency of 5 Hz.Besides,it has good stability and reliability,which can provide enginnering experience and technical reference for multi-module parallel experiments.6.A single power module with 10 GW output power was designed and experimentally studied.At the repetition rate of 20 Hz,the single module could continuously outputs 40 pulses.The peak amplitude of the electrical pulse is about 696 k V,leading edge is about 45 ns,pulse width is about 163 ns,and the electric output power is larger than 8.7 GW.Those resuts are very significannt for further research on the parallel synchronous-synthesis technology for multi-modules of the high power pulse generator.