3D Lumped Thermal Model for Compliant Press‐Pack IGBT Submodule in MMC

ABSTRACT The compliant press‐pack IGBT is widely used in modular multilevel converters (MMCs). The junction temperature rise of press‐pack IGBTs caused by power losses is a critical indicator for the condition monitoring of MMCs. This paper presents a three‐dimensional (3D) lumped thermal model for a compliant press‐pack IGBT submodule and proposes a PSO‐SQP‐based thermal parameter identification method. To generate the training dataset, a finite element (FE) model of the compliant press‐pack IGBT submodule is developed to simulate the transient temperature response under step power excitation. The accuracy of the FE model is validated using infrared (IR) measurement results, while the accuracy of the 3D lumped thermal model is verified by comparison with the FE model. The results demonstrate that the proposed 3D lumped thermal model, combined with the PSO‐SQP identification method, achieves high accuracy and computational efficiency.