Analysis of current distribution on IGBT under unclamped inductive switching conditions

The current filament movement within and between emitter pads of an IGBT under unclamped inductive switching conditions was measured. This measurement was achieved by using a test setup capable of measuring the emitter current distributions in nine independent points over the active area of the IGBT. The measured filament speed into the pads was between the range of 150–400 μm/μs, and the filament speed increases by increasing the collector current. Moreover, current hopping phenomenon was observed between non-neighbouring emitter pads as well.