Novel Lumped-Parameter Thermal Modeling—Part I: Thermal Models for Cuboidal Components

Lumped-parameter thermal models (LPTMs) have been widely used for thermal analysis and management in various electromagnetic devices and systems, e.g., electrical machines and power electronic modules. However, the existing LPTMs suffer from significant temperature misestimation issues due to assumptions of independent and uniform heat flows and/or concentrated loss generation. Meanwhile, they are also incapable of estimating maximum temperature due to inherent structural limitations. This series of papers proposes the novel LPTMs for cuboidal (Part I) and cylindrical (Part II) components from one to three dimensions to address the above critical issues for the first time. The proposed models are obtained analytically based on the multidimensional heat transfer equations, where the interacted heat flow, the distributed loss generation, and the material anisotropy are all considered. Compared to the existing LPTMs, the proposed models exhibit significantly higher estimation accuracy and can simultaneously predict both average and midpoint temperatures. Compared to the finite element analysis (FEA) method, the proposed models can achieve almost identical estimation accuracy while requiring much less computation time. Therefore, they can be used in any applications where LPTMs are required. Finally, both FEA and experiments are used for validation.