MOS-gated thyristors (MCTs) for repetitive high power switching

Certain applications for pulse power require narrow, high current pulses for their implementation. This work was performed to determine if MOS controlled thyristors (MCTs) could be used for these applications. The MCTs were tested as discharge switches in a low inductance circuit delivering 1μs pulses at currents between roughly 3 kA and 11kA, single shot and repetitively at 1, 10, and 50 Hz. Although up to 9000 switching events could be obtained, all the devices failed at some combination of current and repetition rate. Failure was attributed to temperature increases caused by average power dissipated in the thyristor during the switching sequence. A simulation was performed to confirm that the temperature rise was sufficient to account for failure. Considerable heat sinking, and perhaps a better thermal package, would be required before the MCT could be considered for pulse power applications.