Investigation Of A Laser Triggered Switch

As one of the closing switches, laser triggered switch has some advantages such as short time delay, low jitter, low pre-breakdown probability, simple structure, stable and reliable operation, easy to realize remote control, suitable for repetitive, multi-gap or multi-channel operations. So, laser triggered switch is one of the main candidates in the high power closing switch technology. Some basic theoretical and experimental work is carried out on the construction and operation performance of laser triggered switch in this thesis. The relationship between the performance of the switch and some kinds of perameters is preliminarily analysed, future practical switch design could be based on the results.Laser triggered switch is a gas spark switch triggered by a certain laser energy. So, the breakdown properties of a spark gap are first investigated. Then, based on the configuration of laser triggered switch, the operation performances of it are analysed. The results indicate that the key parameters which affect the switch capabilities are laser energy, gas property, gas pressure and electrode shape. The critical breakdown condition, threshold value of laser energy and the relationship between switch performance and some peremeters are simulated and analyzed. The results show that: when the input voltage is approximately 40kV, gap spacing is 0.7 cm with 0.1~0.4MPa gas pressure, the laser breakdown threshold value is about 1.8 mJ. Switch model is set up and simulated by a professional software. After some kinds of different structures being analyzed, the Rogowski structure is chosen to be the electrode shape of the laser triggered switch, the material of electrodes is brass. Furthermore, based on published documents and related experiment results, SF6 and N2 mixture gas is chosen to be the working gas;based on these, some perameters are estimated.Some experiments of the laser triggered switch are carried out. The results show that increasing the laser energy or input voltage woulde be effective methods to decrease the rising time and time delay. When input voltage is lower than 50kV, the rising time is as low as 10 ns, jitter is under 5 ns and the breakdown threshold is 4 mJ (measured from outside of the switch). The results of theoretic analyses and experiments are fundamently consistent; error is under the acceptable range.Finally, a stacked Blumlein high-voltage pulse generator is introduced. Research on this generator is only carried out preliminarily, because of the restriction of experiment condition and research time. More studies would be continued in future.