Closing performances of double-gap laser-triggered vacuum switch

Abstract

To develop high-voltage-pulsed power switches with better performances, a multi-gap laser-triggered vacuum switch is proposed in this study. Based on established test prototype for double-gap laser-triggered vacuum switch, closing processes of double-gap laser-triggered vacuum switch are discussed combined with laser-produced plasma. Closing performances of double-gap laser-triggered vacuum switch under different gap polarity configurations, operating voltages, laser energies and laser split ratios are investigated. Closing time delay characteristics of double-gap laser-triggered vacuum switch and single-gap laser-triggered vacuum switch are compared later. The test results prove that, affected by the imbalanced developed initial plasma between gaps, double-gap laser-triggered vacuum switch with two positive gaps and 1:1 laser split ratio presents best closing performances than other switches. With the rise of laser energy, closing delay time and jitter time of double-gap laser-triggered vacuum switch both decrease, while the influences from increasing voltages are weak. Closing delay time of P–P type double-gap laser-triggered vacuum switch can be controlled within 103 ± 1.5 ns under 90 mJ laser energy, and it is about 10 ns longer than single-gap laser-triggered vacuum switch. For some direct current applications with changing voltage directions, P–N type double-gap laser-triggered vacuum switch with 1:1 laser split ratio shows more stable closing performances. In addition, closing performances of double-gap laser-triggered vacuum switch can be further improved by optimizing the developments of initial plasma in series gaps.