Subnanosecond switching of standard thyristors triggered in impact-ionization wave mode by a high-voltage PCSS driver

Abstract

Power thyristors triggered in impact-ionization wave mode are capable to replace spark gap switches, bringing major advantages into repetitive pulsed power industrial applications. Low power thyristors remained for the moment out of the research focus, most likely because of the challenging driver, which must provide a sufficiently fast and powerful triggering pulse. This paper describes subnanosecond switching of standard off-the-shelf low-power thyristors in impact-ionization wave mode, running by the PCSS trigger generator based on the laser diode and GaAs switches. Several types of thyristors with a rated voltage from 0.6 kV to 2.2 kV have been tested running by both a commercial FID and by the tailored PCSS generators. The triggering and current flow stages were examined. For the 1.6 kV thyristor (TO-247 package), the following parameters have been obtained: switching time 250 ps, dI/dt up to 12 kA/μs, amplitude 85 A and FWHM about 60 ns. In this mode, the first 103 pulses have not revealed any thyristor degradation.