Electrical field analysis of press-pack IGBTs

High voltage IGBT module is the ideal option for the VSC-HVDC power transmission application. At present, bonded power module and press-pack module are available packaging technology for the high voltage IGBT. The press-pack packaging has such advantages as low inductance, low thermal impedance and short circuit failure mode over the bonded power module, and especially suits for the high power serial topology application. However, the characteristics and failure mechanisms of press-pack IGBTs are much less known with limited literature published. In this paper, we present the electrical field analysis of a 3D model of a press-pack IGBTs under the DC rating voltage test condition. We obtain the electrical field distribution results by using an FEM based electromagnetic field solver. The results reveal the potential electrical insulation failure modes of the press-pack IGBTs under DC rating voltage test condition: corona discharge at the edge of the silver plate, partial discharge at the micro gap between the die and PEEK frame and surface discharge at the surface of the PEEK frame.