Study On The Repetition-rate Long-lifetime Gas Spark Switch

Pulsed power technology has been used extensively in the fields of scientific experiments, national defense, biomedicine and environmental protection etc. As one of the crucial components, a high-energy switch with high pulse repetition rate, high voltage, high current, long life-time, fast turn-on time and low jitter is greatly expected to meet the rapid development of pulsed power system. In this thesis the field-distortion rotary-arc gas spark switch is fully explored.This thesis initiates with the review of different types of high power pulse closing switches including the operating principles, electrical parameters, advantages, disadvantages and the recent development trend of high power pulse closing switches. Especially the working mechanisms and the classification of the gas spark switch are introduced here.The high current which flows in the closing gas spark switch results in the electrode erosion that influences largely the switch performance especially for the lifetime. A field- distortion rotary-arc gas spark switch which combines the advantages of rotary-arc gap and rail gap is developed which can reduce electrode erosion effectively and then extend the switch lifetime by the rotation of the arc achieved by providing self-induced rotating magnetic field and the optimization of electrode configuration . The rotation of arcs can reduce the period of the heat action between the arc and the electrode, and the electrode optimization can prevent the local concentrated arc and lessen the electrode erosion. The triggered single-shot discharge experiment has been undertaken with different switch configurations, different electrode materials and different current waveforms. It indicates that the rotary-arc gap switch employing a sharp knife-edge electrode as a third trigger electrode can distinctly reduce the electrode erosion and prolong the lifetime of the switch. And the static self-breakdown of the switch indicates that after electrode optimization the static self-breakdown voltage is stable and the distribution of electric field in the gap is mostly uniform. Some triggering modes and triggering circuits for triggered gas spark switch are presented in this thesis. In order to reduce the breakdown delay and its jitter and to improve the stability of the triggered gas spark switch, a trigger system with the amplitude of –30KV and the risetime 5.4ns is designed and built. The trigger system can produce trigger pulses with the rate of rise up to 5.5KV/ns. The experimental results of the application of the triggering system are presented and indicate that the switch breakdown delay and its jitter will be lowered with the increasing rate of rise of the triggering pulse.The insulation recovery process and characteristics of rep-rate gas spark switch are introduced in the thesis. The methods for enhancing the insulation recovery velocity of spark switch with gas flowing or without and the working modes and its characteristics of rep-rate spark switch are summarized here. The rep-rate working mode adapted to the field-distortion RAG spark switch without the gas flowing is presented in the thesis. The experiments of rep-rate quasi-overvolted switch without gas flowing have been undertaken and the results indicate that the switch developed here can experience the rep-rate breakdown with the high rep-rate up to 3kHz and the high voltage up to 6kV.For the experiments of rep-rate switch breakdown, a high rep-rate high voltage pulse generator including a triggering control system based on MCU 89C51 and a quick charging system based on L-C resonant circuit is developed in the thesis. The triggering control system can produce the control signal for the IGBT driver module. It has a good immunity to disturbances and flexible control modes, i.e., the single-shot and rep-rate whose frequency range covers form 1Hz to 3kHz with 1Hz resolution and +5V magnitude. The high rep-rate high voltage pulse generator mainly comprises L-C resonant charging system and a IGBT controlled by MCU. It produces the high rep-rate high v...