Surge current capability of IGBTs

Commonly an IGBT cannot withstand a surge-current pulse (large overcurrent with a duration of some milliseconds) due to the current saturation characteristic of this device. In the case of a converter´s single device failure the IGBT switches are driven into pulse-blocking mode to prevent a DC-link short-circuit and subsequent IGBT failures. This strategy leads to an asymmetric short circuit of the load. The paper introduces the possibility to symmetrize the load short circuit with active turned on IGBTs and shows first measurements on high-voltage press-pack IGBT chips under heavy overcurrent condition with increased gate voltage.