Speaker
Description
"Thyristor-Based Switches Operating in Impact-Ionization Wave Mode for Pulsed Power Applications"
Thyristors of tablet design with diameters of silicon wafers of 40 to 56 mm and an operating voltage of 2 to
2.4 kV DC were triggered by an external overvoltage pulse applied across the thyristor main electrodes. In
experiments a voltage rise rate across the thyristor was changed from 1 to 6 kV/ns. Under such conditions
the thyristor closing process occurred due to initiation and propagation of a fast ionization front across the
semiconductor structure, which fills the structure with dense electron-hole plasma within 200 to 400 ps. The
thyristor based switches contained 2 to 9 series connected thyristors and operated in this triggering mode in
different discharge circuits. Operating voltage was 5 to 20 kV, capacitance of discharge capacitors was 2 μF
to 1.2 mF, and stored energy was 0.4 to 15 kJ.The experimental results obtained covered the following range
of discharge parameters: discharge current amplitude of 10 to 200 kA, current rise rate of 15 to 130 kA/μs,
current rise time (0.1-0.9 level) of 0.4 to 5 μs, pulse duration (FWHM) of 1 to 20 μs, and switching efficiency
of 0.85 to 0.97. Effect of the voltage rise rate at the triggering stage as well as temperature of the silicon
wafer on the thyristors main switching characteristics will be shown. Results of the thyristors testing in pulse
repetition mode will be given. The experimental circuitry, tested switches design, and results obtained will be
discussed.
