Short circuit protection of high speed, high power IGBT modules

At SLAC, research and development for the next linear collider (NLC) is progressing. The 8-Pack project is a test stand in which key NLC components will be developed. Presently the setup is such that an induction modulator [R. L. Cassel et al., The Prototype Solid State Induction Modulator for SLAC NLC] will generate 400 kV, 1200 A, and 1.6 /spl mu/s flattop pulse to drive four XL4 X-band klystrons. This requires the use of 76 high power IGBT modules operating in parallel at 3600 A and up to 2200 V each. IGBT switching speeds and short circuit protection from klystron arcs are major concerns. This paper describes a gate drive circuit with a new method to protect IGBT modules under short circuit conditions. Using a dI/dt control technique, the gate drive circuit enabled the Mitsubishi module CM600HB-90H to switch 4000 A at speeds up to 10 kA//spl mu/s in normal operation, while holding the short circuit peak-current to about 8000 A. Results from the single IGBT test and the 8-Pack Modulator prototype will be presented.