A Comprehensive Review of High-Frequency Short-Circuit Oscillation Modes in IGBT Applications

In this paper, the effect of the main circuit parameters and device elements on instabilities of IGBTs during short circuit events are evaluated in terms of electric field and electron density distributions. The following aspects have been covered: (a) the full physical analysis of the oscillation modes, while addressing the main root causes using an IGBT capacitive model, (b) the effect of both device design and circuit parameters on the short circuit behaviour with respect to the oscillations phenomenon, and (c) the methods to mitigate the oscillations at both device and circuit levels. Results show that the most effective way to mitigate the unstable behavior is by shaping the carrier profile in a way that the electric field is sufficiently strong at the emitter side under short circuit conditions. Another relevant result is that a high-impedance configuration of the gate driver can improve oscillation immunity.