Improved Natural-Air-Convection-Cooling Formulas for Medium Frequency Transformer Design Optimization

Conference: PCIM Europe digital days 2021 - International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management
05/03/2021 - 05/07/2021 at Online

Proceedings: PCIM Europe digital days 2021

Pages: 8Language: englishTyp: PDF

Authors:
Le Roy, Jonas; Mogorovic, Marko; Dujic, Drazen (Power Electronics Laboratory (PEL), École Polytechnique Fédérale de Lausanne (EPFL), Switzerland)

Abstract:
This paper provides accurate analytic models for a computationally efficient estimation of the natural convection cooling coefficients for typical geometries, such as those encountered in transformers. Proper thermal coordination is an essential step of any transformer design, especially when it comes to medium frequency operation, where the cooling surfaces are greatly reduced due to the frequency scaling. Available empirical formulas, derived for simple geometries, have a limited applicability to such complex structures. In this work, analytic models are derived based on extensive finite element method simulations that accurately describe the convective heat transfer of the geometries of interest. The proposed models improve accuracy substantially compared to the available models and have several orders of magnitude faster execution referred to finite element method simulations.