Current measurement and short-circuit protection of an IGBT based on module parasitics

In this paper, a short-circuit protection of an IGBT, based on current measurement is proposed. The IGBT collector current estimate is obtained by filtering the voltage between the auxiliary emitter and the power emitter terminals of an IGBT module. The proposed scheme utilizes a large bandwidth analog circuit which enables to the detect fault current regardless of the current slope. According to the experiments, the proposed circuit can detect faults before desaturation of the IGBT, which is a major benefit compared to the traditional methods based on IGBT saturation voltage measurement.