Internal dynamics of IGBT under fault current limiting gate control

With the advent of high power high voltage IGBTs, it is feasible to use sophisticated gate drive circuits to obtain improved switching performance and ruggedness. Short-circuit and over-current fault protections are critical issues in gate drive circuits for high power converters. This paper evaluates the effect of gate control to limit the fault current in an IGBT in terms of its internal dynamics. The internal dynamics are analyzed using a two-dimensional device simulator. The effects of short-circuit and over-current faults in an IGBT power converter are studied by examining the fault characteristics over a range of fault inductance values. This study highlights the advantages of reduced fault current level, reduced power dissipation, and improved ruggedness that can be gained by the fault current limiting gate protection techniques. The simulation studies match trends observed in experimental results.