Research On Low Jitter Triggered Main Switch And Trigger Pulse

Pulse power source technology is the basis of high-power microwave technology.With the continuous development of high-power microwave technology,higher requirements are placed on the output power,pulse width and structural compactness of the pulse power source,due to its physical limitations such as pulse shortening,parallel operation of multi-module systems has become an effective way to further develop pulse power technology.This requires the pulse power system output to be precisely controlled,compact and modular,with the main switch being a key component.Electric pulse-triggered gas switches have advantages in terms of peak power,compactness,and environmental adaptability.Therefore,research on precise triggering,low jitter,and modularization is of great significance.For the precise control of pulse power system and the precise synchronous triggering of multi-module parallel system,this paper designs a high-power repetitive corona stabilized triggered switch?CSTS?based on corona stability principle.Achieving precise control of the pulse power system with low jitter,which lay good foundation for the next step to realize multi-module parallel research and improve the overall system capability.The main work and results of the thesis are reflected in the following aspects:1.Research on CSTS discharge processBased on the gas breakdown theory in extremely non-uniform field,the discharge process is analyzed to investigate the effect of stabilized corona on the switching performance.The theoretical formula of the corona breakdown field is obtained by theoretical derivation,and then the critical conditions from stabilized corona to the formation of streamer are calculated.According to the detailed process of breakdown,the reasons that stabilized corona increases the stability of the switch are analyzed.2.design and simulation of CSTS?1?The main feature of the CSTS design is to replace the traditional needle-shaped trigger electrode with a ring-shaped trigger electrode,and adopt the design of the main-sub-trigger ring to specify the discharge channels;at the same time,the insulating medium adopts a gas mixture of N₂ and SF₆;?2?The static E-field simulation of the designed CSTS structure shows that uniform background field exists between the electrodes and local extremely non-uniform field exists at the tip of trigger electrode;in the meanwhile,the trigger signal increases the field non-uniform coefficient by up to 37%,which proves the necessity of triggering of corona stabilized switch;?3?Using the calculated critical conditions of formation of streamer combined with the electric field simulation,the critical volume of stabilized corona is able to be obtained.According to the preliminary analysis of the simulation results,the factors affecting the critical volume of stabilized corona:applied voltage,trigger electrode structure,gas pressure and gas type.The higher the applied voltage,the lower the gas pressure,and the higher the content of N₂ in the mixed gas,the larger the critical volume of stabilized corona.3,design and testing of trigger generatorBased on the saturable pulse transformer and Marx generator,a low-jitter compact trigger generator is designed.The test results show that the peak voltage of trigger pulse is 79.6kV,the dropping edge is 144ns,and the 50 repetitive pulses jitter is 0.64ns.4.Exploring the factors affecting the performance of CSTS.?1?By changing the trigger electrode protrude length D_p which is associated with the magnitude of local field enhancement.investigating the self-breakdown voltage and stability,and jitters of switch under triggering.Besides,the amplitude requirements and the working range of the switch are obtained.?2?Exploring the influence of gas mixture with different SF₆ content on the performance of the switch.The experimental results show that when the SF₆ content is15%and the pressure is 0.2MPa,the self-breakdown voltage of the switch is 551kV,and the operation is stable.When the switch is in triggering condition,the working range is 46.4%-93.5%of the self-breakdown voltage.The jitter is 0.57 ns and the minimum trigger voltage is 55.8%of the peak trigger voltage.?3?Research on the stability of multi-module operated in parallel based on single trigger.As shown in the results,jitters of each module in two-module operations are lower than 10ns,and the lowest jitter is 4.8ns.The stability drops rapidly in the three-module operation,which indicates a strong influence between modules operated in parallel.5,microsecond high-speed camera diagnosing discharge processThe shape of the channel during the discharge process and the insulation recovery process of the switch are diagnosed by the microsecond high-speed camera.It is found that the higher the breakdown voltage,the larger the channel volume.Besides,the channel volume expands rapidly when the air pressure is lower than atmospheric pressure.When the voltage is about 200kV,the insulation recovery process time of CSTS is 1-2ms.