Fast and Accurate Temperature Estimation of Three-level IGBT Converter Based on 3-D Coupled Thermal Model

The wearout and failure of power module and converter equipment are mainly caused by temperature factor, so real-time and accurate junction temperature estimation is of vital importance, which is beneficial to realize more reliable and economical energy conversion. In order to obtain the accurate and detailed temperature distribution of the key nodes inside the converter, the thermal coupling effects of different levels are considered in this paper, a complete three-dimensional (3-D) coupled thermal network model for three-level IGBT converter is established by obtaining equivalent RC thermal impedance parameters from the FEM analysis, and based on electric-thermal coupling, fast and accurate transient junction temperature extraction is thereby realized under actual working conditions. Finally, the accuracy of the proposed model is verified by the good agreement between the Matlab calculation, the FEM simulation and the experimental measurement.