Multichip thyristor performance

The performance of the ABB CSF 672-11000 multichip thyristor has been studied under wide pulse conditions. The thyristor consists of four symmetric 2.8 kV, 47 mm diameter chips in a single compact package. The gate driver is optically isolated with the power parasitically derived from the anode voltage. A dual parallel PFN testbed was used for the study. Reliable operation was demonstrated using a single PFN at 10 kV with a peak current of 31.4 kA at a pulse width of 557 /spl mu/s (FWHM). With dual PFNs a chip shorted in one device at 5.0 kV and 32 kA. A second device was tested for 144 pulses up to 6.8 kV and a peak current of 42.4 kA with a di/dt of 2.0 kA//spl mu/s before a single chip failed. In both cases the devices were still usable and additional testing was continued at 42.4 kA. The results obtained favors the concept of building high voltage thyristor stacks with extra chips to provide a graceful degradation and long life capability.