Evaluation of a 7 kV 80 kA SGTO module

This work was undertaken to investigate the switching performance of Super GTO's (SGTO) under conditions of fast rise times up to 25 kA/us, high peak current up to 80 kA, blocking voltage of 7 kV and pulse width of 100 us. The device under test is a switch that is made of two 3.5 kV modules placed in series; each containing eight SGTO die in parallel. The SGTO die developed by Silicon Power Corporation (SPCO) have a very small gate structure of approximately 10 mu;m. The benefit of this small gate structure is that it allows the device to reach full conduction faster than a conventional thyristor and is therefore optimized for fast turn-on (high di/dt). The SGTO die is a very efficient device having a current density of 29.7 A/mm² at 10 kA. Each SGTO die can hold of 3.5 kV and can conduct 10 kA. The efficiency of the SGTO die warrants evaluation of this dual module SGTO switch that is rated at 7 kV and 80 kA. The evaluation of the dual module will also determine its overall ability to be used in other voltage and current configurations for various applications by determining its safe operating area (SOA). We have evaluated the switch at 6 kV at a maximum current of 86 kA over a 120 mu;s pulse width and with a di/dt of 25 kA/μs.