Short-Circuit Capability Optimization of Press-Pack IGBT by Improving Active Edge Heat Dissipation

Press-pack insulated gate bipolar transistor (PP-IGBT) device has been widely used in VSC-HVdc converters. Research on the optimization method of short-circuit capability is crucial to improve the short-circuit robustness and reliability of PP-IGBT. Aiming at the problem of device failure due to transient overstress induced by press-pack packaging, this article proposes a short-circuit capability optimization method of PP-IGBT that improving the active edge heat dissipation by using silver conductive adhesive (SCA). First, the short-circuit capability is evaluated by experimental test, and the failure conditions and positions are obtained. Second, based on the finite element method simulation, the electrical-thermal-mechanical stress of PP-IGBT under short-circuit transients is analyzed and the optimization method by using SCA is proposed. Third, the short-circuit capability of PP-IGBT with SCA coating is tested and verified. Lastly, the potential of the SCA coating under different short-circuit voltage levels is discussed. The results indicate that the transient thermal shock at the active corner of the chip that is not in direct contact with the emitter molybdenum plate causes device failure and improving the active edge heat dissipation by SCA could be an effective approach to improve the short-circuit capability of PP-IGBT.