真空界面是脉冲功率装置的薄弱环节, 对于重频运行的系统, 该问题更为突出。介绍了一种应用于重频脉冲驱动源的陶瓷绝缘子真空界面。首先依据真空沿面闪络设计原则给出了一种改进型同轴馈电陶瓷真空界面绝缘结构, 该结构采用陶瓷-金属钎焊连接形式; 通过采取均压、屏蔽措施, 静电场模拟结果显示, 陶瓷沿面电场分布均匀, 总场强小于100 kV/cm, 沿面分量小于70 kV/cm, 阴、阳极三结合点场强均小于40 kV/cm; 在输出幅值600 kV、脉宽80 ns、重复频率1~5 Hz可调的脉冲功率驱动源上进行了实验测试, 陶瓷真空界面平均绝缘场强达到44 kV/cm, 运行稳定; 采取(0-1)分布对实验结果进行了统计分析, 置信度取为0.9时, 陶瓷真空界面的可靠度大于97%。最后, 还探讨了表面处理工艺对闪络电压的影响, 实验发现, 增加表面粗糙度可有效提高陶瓷绝缘子的闪络电压。

An improved coaxial high-voltage ceramic vacuum interface applied in a repetitive pulse generator, was designed and tested. Results from electro-static calculation by ANSYS show that the electric field (E-field) distribution within the improved interface is uniform. Key structures such as the anode and the cathode shielding rings of the ceramic insulator were optimized to significantly reduce E-field stresses. Aging experiments with this interface were conducted in the condition of about 600 kV, 80 ns and 1-5 Hz pulses. The preliminary test shows that the ceramic vacuum interface can work stably with the hold-off field of more than 44 kV/cm. The experimental results agree with the simulated results. Finally, the influence of the surface treatment on the ceramic flashover characteristics was discussed.