A Miniaturized Sealed-Off Double-Gap Pseudospark Switch for High Power and High Repetition Rate Pulsed Discharge Applications

Pulsed power systems can deliver high peak power in a micro/nano-second timescale to various loads in scientific and industrial applications, whose performances are significantly influenced by the pulsed discharge switch. This article presents the development and comprehensive tests of a miniaturized sealed-off pseudospark switch. The structure of double-gap and multi-channel is adopted to achieve the high hold-off voltage and high current capacity. In single pulse tests, the influence of pressure in the switch is analyzed. As the pressure increases, values of multiple parameters decrease, like self-breakdown voltage, trigger delay, and voltage dropping time. In a wide pressure range, trigger jitter is below 3 ns, and the minimum is <1 ns. At low pressure, the transient voltage across two gaps becomes inconsistent, and two types of current quenching are observed, which are related to processes occurring on cathode surface. In repetitive pulse tests, the direct repetitive operation is up to 3.5 kHz while higher repetition rate is limited by the trigger system. In double-pulse tests, the maximum repetition rate can be higher than 8 kHz for 40 kV pulsed voltage. Meanwhile, the insulation recovery speed is higher at lower pressure, and as the time delay between two pulses increases, the second pulse breakdown voltage increases nonlinearly. In high current tests, the switch is also used in metal wire explosion experiments and operates at the condition of 30 kV/40 kA for more than 10 ⁴ shots without performance degradation. Further lifetime tests point out that the switch can work for >10 ⁶ shots stably at moderate current. Experiments prove that the designed switch has superior performances including high hold-off voltage (>50 kV), low jitter (<1 ns), high repetition rate (>3.5 kHz), high peak current (>40 kA), long lifetime (>10 ⁶ shots) and miniaturized size.