Triggered switches for high repetition rate commutation of capacitive stores

Abstract

This paper contains the results of development and testing of a switch used in a high-voltage pulse-frequency generator for use in pilot facilities. The design developed for switches is based on the scheme of three-electrode spark gap switch which involves purging of the interelectrode gaps with intense flow of air for forced removal from the working gap of the plasma and products of electrode erosion which formed as a result of previous discharge. The fairly high values of the switched energy, power and service life are attained by manufacturing the switch electrodes of high-melting materials based on tungsten and copper compounds and by increasing the electrode working surface. The switch is triggered by an overvoltage pulse emerging as a result of transients in the resonance charging circuit of capacitive store. The stability of operation of the switch is accomplished by exposing the interelectrode gaps of the switch to ultraviolet illumination induced by an additional low-power spark gap switch which is likewise controlled by transients in the resonance charging circuit of the capacitive store. The switch is characterized by the following parameters: average switched power, up to 30 kW; switched energy, 1 to 10 J; pulse repetition rate, 0.1 to 3 kHz; peak voltage, up to 25 kV.