Reliability Study and Modelling of IGBT Press-Pack Power Modules

The IGBT press-pack provides low inductance and simple module stack for high power and high voltage applications. In this work, the reliability of IGBT Press-Pack power modules is experimentally tested under RBSOA conditions to investigate their limitation and current scalability. The internal current distribution is analyzed by detailed 3D FEM simulation. This work reveals that the uneven distribution of current density is caused by different impedance in each IGBT die current conducting path, due to skin and proximity effects during switching transient. Stray and mutual inductances also affect current paths depending upon the location of IGBT within the package. The unbalanced switching times become larger as the package size increases with more parallel configured IGBTs. By extracting the FEM data into the proposed circuit model, the electrical performance will be discussed in detail.