Explosion tests on IGBT high voltage modules

In this paper, we report on surge current experiments with IGBT modules in low inductance, snubberless circuits. We give design guidelines for robust modules and robust converter designs, discuss scenarios of consequential damage and propose worst case test conditions for explosion safety. For wire bonded modules, the limit for material ejection is at a stored capacitive energy of about 10 kJ. In a good design, the shock wave trajectory is defined and no metallic parts obstruct the plasma expansion. The worst case damage occurs if, initially, a single chip fails. Press-pack modules can be designed to contain the plasma inside the housing in the case of a short circuit. Simple protective measures are sufficient to protect personnel.