兆伏级串级自触发开关脉冲击穿特性影响机制及优化  

Influence mechanisms and optimization of pulsed breakdown characteristics of a megavolt class cascade self-triggered switch

作　　者：王天驰 谢霖燊[2] 李俊娜[3] 杨友恒 黄涛[2] 陈志强[2] 郭帆[2] 杜应超[1] 陈伟[2] WANG Tianchi;XIE Linshen;LI Junna;YANG Youheng;HUANG Tao;CHEN Zhiqiang;GUO Fan;DU Yingchao;CHEN Wei(Key Laboratory of Particle&Radiation Imaging(Tsinghua University),Ministry of Education,Beijing 100084,China;State Key Laboratory of Intense Pulsed Radiation Simulation and Effect,Northwest Institute of Nuclear Technology,Xi'an 710024,China;State Key Laboratory of Electrical Insulation and Power Equipment,Xi'an Jiaotong University,Xi'an 710049,China)

机构地区：[1]粒子技术与辐射成像教育部重点实验室(清华大学),北京100084 [2]西北核技术研究所强脉冲辐射环境模拟与效应国家重点实验室,西安710024 [3]西安交通大学电力设备电气绝缘国家重点实验室,西安710049

出　　处：《清华大学学报（自然科学版）》2023年第1期114-124,共11页Journal of Tsinghua University(Science and Technology)

摘　　要：大型脉冲功率装置中使用的兆伏级开关常采用串级结构以提高工作电压并保证开关电场的均匀性。在脉冲电压上升速率固定且单级开关击穿概率服从Weibull分布前提下,推导了串级开关击穿概率分布模型,并分析了3级串级开关击穿特性的影响机制。在能保证各单级开关击穿特性一致性较好的条件下,触发3级开关时,后击穿的2级在高过压下击穿,每级开关的平均击穿电压降低,开关整体击穿时延抖动与单级触发开关相当;触发1级开关时,大概率是触发级先击穿、2个自击穿级在高过压下击穿,开关整体抖动远小于自击穿抖动,每级开关的平均击穿电压比触发3级时更高,但由于自击穿级仍有小概率先击穿,开关整体抖动约为触发3级时的2倍。在前沿约300 ns的脉冲电压下实验研究了串级开关的击穿特性,其中单级开关采用自触发持续预电离方式以保证特性的一致性。结果表明,开关工作电压0.8~2.0 MV范围内,触发1级时,时延抖动2.9~7.7 ns、电压分散性0.51%~2.21%,触发3级时,时延抖动2.3~3.6 ns、电压分散性0.59%~0.91%,验证了模型分析所得的规律,且实现了对原有串级开关击穿特性的优化。此外,由于0.3 MPa以上高气压时开关的自击穿状态更稳定,触发1级与触发3级时开关整体抖动基本相当。Megavolt switches in large pulses typically use a cascade configuration to increase operating voltage and ensure electric field uniformity.We must reduce their jitter when we need multipulse superposition to obtain a higher voltage pulse.Moreover,in the high-altitude electromagnetic pulse simulator,the megavolt pulsed switch needs to adopt the self-triggering technique to simplify the structure and reduce weight for good mobility and hoisting requirements.However,it is difficult to carry out a large number of experiments and completely reveal the influence mechanisms of the characteristics of megavolt switches via experiments.Therefore,this paper derives a breakdown probability distribution model of a cascade switch based on the characteristic parameters of a single-stage switch,which can be obtained easier from experiments.The experiment of the cascade switch is then carried out to validate the model analysis.In the model,we assume that the rising rate of the pulse voltage is a constant and that the breakdown probability of a single-stage switch follows the Weibull distribution.It is common in cascade switches to allow one stage to break down in triggered mode while others are in self-breakdown mode due to overvoltage.When the cascade switch has n stages,and one stage is triggered,it is seen as three equivalent switches based on their breakdown sequence.This paper assumes that x self-breakdown stages first close,the triggered stage closes next,and finally,(n-x-1)self-breakdown stages close.The range of x is[0,n-1].Then the breakdown probability distribution model of each equivalent switch can be derived using the existing calculation method.The influence mechanisms of the breakdown characteristics of a three-stage cascade switch are semiquantitatively analyzed based on the model.If the uniformity of breakdown characteristics of each triggered switch can be guaranteed and three stages are all triggered,the switch jitter is approximately equal to the jitter of a single-stage triggered switch because the latter two

关 键 词：串级气体开关 预电离 脉冲击穿 抖动 

分 类 号：TM89[电气工程—高电压与绝缘技术] TL58[核科学技术—核技术及应用]