The Design And Research Of A Field-breakdown Laser Triggered Vacuum Switch

Laser triggered vacuum switch is a development of the switching device whichcombines the technology of vacuum triggered switch and laser triggered gas switch. Thatmakes it own the advantage of wider working voltage range and larger current capacity.And laser could avoid the misconduct and trigger the switch in a remote area of conductionas its excellent parallel characteristic. In this paper, the conduction mechanism of the switchhas been researched, the materials and the structure of the switch has been picked anddesigned, the appropriate laser source has been selected on the match, and some aspects ofinfluence has been studied in order to make the switch has a lower delay time and jittertime.By the analysis and comparison of melting point, the photoelectric power function,thermal power function and so on, a mixed materials of titanium and potassium chloridehas been chosen as its trigger electrode and anaerobic copper as its main electrode. Theexperiment and simulation also demonstrates that the switch with muti-electrodes issuperior to the switch with plane electrodes, placing the trigger electrode on the surface ofthe cathode where is close to the anode is better than other places, and a metal shieldingcover around the electrodes could effectively maintain the internal vacuum and theself-breakdown voltage of the switch.Nd3+: YAG is suggested to be used as the laser source with the wavelength of1064nm. When the laser arrives the trigger electrode, initial plasma comes from this electrodevia the photoelectric effect and heat effect and moves to another electrode stimulating moreplasma via the effect of the applied electric field, which eventually makes the switchconducted. Experimental results also show that just dozens of mJ laser pulse energy isneeded to trigger the switch with muti-electrodes, which proves that the main power thatmakes the switch conducted comes from the applied electric field instead of laser energy.In addition, according to the results of the experiment, the increase of the maincapacitor in the circuit can make laser triggered the delay time of the laser triggeredvacuum switch reduced, while the increase of the laser energy can effectively make thejitter time of laser trigger vacuum switch reduced. The increase of the applied voltage couldreduce the delay time and jitter time at the same time.