较高场畸变系数的大电流三电极气体开关

High-current three-electrode gas switch with high field distortion coefficient

气体开关作为脉冲功率装置的关键部件,其自击穿概率以及触发放电延时抖动对整个脉冲功率系统具有至关重要的影响。降低开关工作系数有利于提高开关稳定性,但延时抖动会随之增大。针对用于磁驱动实验的10 MA级大电流装置应用需求,设计了一种具有较高场畸变系数、能在较低工作系数条件下稳定工作的三电极气体开关,并开展了该开关的性能研究。模拟与实验结果表明:在触发电压与充电电压相当的条件下,开关的场畸变系数接近4,开关工作系数高于60%时,开关具有较低的延时抖动,抖动均方根小于3 ns。结合该开关设计了一个两级Marx储能模块,充电电压±50 kV条件下短路放电,模块回路放电电流峰值达到150 kA、周期2μs。上千次放电实验后,开关电极表面未发生明显烧蚀,工作正常。工作系数68.5%时,共计4000发实验中未出现自放电现象,自击穿概率低于2.5×10^(−4)。上述结果表明该开关可满足300~400只开关同时工作的大电流装置需求。

As a key component of pulse power device,the self-breakdown probability of gas switch and the jitter of trigger discharge delay have a crucial impact on the whole pulse power system.Reducing the working coefficient of the switch is beneficial to improve the stability of the switch,but the delay jitter will increase accordingly.Aiming at the application requirements of 10 MA level high-current devices used in magnetically driven experiments,a three-electrode gas switch with high field distortion coefficient and stable operation under low operating coefficient was designed and its performance was studied.The simulated and experimental results show that when the trigger voltage is equal to the charging voltage,the field distortion coefficient is close to 4,and when the switch operating coefficient is higher than 60%,the switch has low delay jitter with the root mean square of less than 3 ns.Combined with the proposed switch,a two-stage Marx energy storage module was designed.When discharged under the condition of charging voltage±50 kV and short circuit,its peak discharge current can reach 150 kA with a period of 2μs.After thousands of discharge experiments,no obvious ablation occurred on the surface of the switch electrodes,and it worked normally.When the working coefficient was 68.5%,there were no self-discharge phenomena in a total of 4000 rounds,and the self-breakdown probability is lower than 2.5×10^(−4).The above results show that the switch can meet the needs of high current devices with 300-400 simultaneously working switches.