Primary High-Voltage Thyristor-Based Switches Triggerred in Impact Ionization Wave Mode for High-Power SOS Generators

The paper describes the investigation of fast thyristor-based switches operating as a primary switch in nanosecond pulse generators with a semiconductor opening switch (SOS). Commercially available thyristors with the diameter of the silicon wafer of 40 mm and an operating voltage of 2.4 kV DC were used. The thyristor-based switches contained 2 to 6 series connected thyristors and operated in this triggering mode in different discharge circuits. Switch blocking voltage was 4 to 12 kV and stored energy was 16 J. The following discharge parameters were obtained: discharge current amplitude of 8 kA, maximum current rise rate of 40 kA/μs, current pulse duration FWHM of ~1 μs, and switching efficiency of ~0.9. The intrinsic recovery time of the tested thyristors was determined, which was close to 1 ms. Therefore, the maximum PRF was up to ~1 kHz in a burst mode. More than 10
⁶
shots were performed. After that, no thyristor degradation was observed. The novel circuit design of the all-solid-state SOS generator with output voltage up to 300 kV and peak power up to 250 MW was developed. Thyristor- based switch (12 kV, 7 kA, 500 ns) triggered in impact ionization wave mode was used as a primary switch. Implementation of such a switch allowed significantly increasing the efficiency of the SOS generator and decreasing its cost due to reducing the number of magnetic switches.