Improving the Short-Circuit Reliability in IGBTs: How to Mitigate Oscillations

Paula Diaz Reigosa, Francesco Iannuzzo, Munaf Rahimo, Chiara Corvasce, Frede Blaabjerg
2018 IEEE transactions on power electronics  
In this paper, the oscillation mechanism limiting the ruggedness of IGBTs is investigated through both circuit and device analysis. The work presented here is based on a timedomain approach for two different IGBT cell structures (i.e., trench-gate and planar), illustrating the 2-D effects during one oscillation cycle. It has been found that the gate capacitance varies according with the strength of the electric field near the emitter, which in turn leads to charge-storage effects associated
more » ... low carrier velocity. For the first time, it has been discovered that a parametric oscillation takes place during the short-circuit in IGBTs, whose time-varying element is the Miller capacitance, which is involved in the amplification mechanism. This hypothesis has been validated through simulations and its mitigation is possible by increasing the electric field at the emitter of the IGBT with the purpose of counteracting the Kirk Effect.
doi:10.1109/tpel.2017.2783044 fatcat:upxcpdqht5czhggtllqlckzvgi