Scattering parameter approach applied to the stability analysis of power IGBTs in short circuit

Abstract Power IGBTs operating at high voltage and current under particular load and driving conditions, particularly in short circuit, can be affected by unstable phenomena that can reduce the device’s reliability and increase the generation of electromagnetic interference. In this paper we propose, for the first time, the analysis of the device’s stability based on scattering parameter approach applied to power IGBT operated under different load and driving conditions. The Stern stability factor ( K -factor) was used to individuate the frequency range where the device can be potentially unstable and investigate about the influence of the external circuit on the circuit stability. The proposed method has been experimentally verified on discrete IGBTs and extended to FEM simulation. It can supply very important suggestions to the device’s designers for improving the device stability and to the circuit designer for preventing the instabilities by using a proper choice of driving and load circuits.