Heat Dissipation System Modeling of Three-level Converter Considering Thermal Coupling Effects

The heat dissipation problem is the key to restrict the capacity and reliability of high-power converters. In this paper, aiming at the air-cooled heat dissipation system of high-power neutral-point clamped (NPC) three-level converter with specific radiator structure, the thermal impedance parameters are extracted by using finite-element method (FEM), and the overall three-dimensional (3-D) coupling thermal network model of the converter is thereby established. Both the thermal coupling effects between different power device chips and between different insulated gate bipolar transistor (IGBT) modules are comprehensively considered. The proposed thermal model can truly reflect the junction temperature of each chip in IGBT module and accurately estimate the detailed temperature in the critical locations of high-power converter, which is of vital importance to the device selection, heat dissipation design, reliability evaluation and life prediction of high-power converter.