Validation and Parametric Investigations Using a Lumped Thermal Parameter Model of an Internal Permanent Magnet Motor

Sebastien Sequeira, Kevin Bennion, J. Cousineau, Sreekant Narumanchi, Gilberto Moreno, Satish Kumar, Yogendra Joshi

Research output: Contribution to conferencePaperpeer-review

3 Scopus Citations


One of the key challenges for the electric vehicle industry is to develop high-power-density electric motors. Achieving higher power density requires efficient heat removal from inside the motor. In order to improve thermal management, a multi-physics modeling framework that is able to accurately predict the behavior of the motor, while being computationally efficient, is essential. This paper firstpresents a detailed validation of a Lumped Parameter Thermal Network (LPTN) model of an Internal Permanent Magnet (IPM) synchronous motor within the commercially available Motor-CAD® modeling environment. The IPM motor's stator is studied at steady state, and winding losses are generated by a constant DC current. The validation is based on temperature comparison with experimental data and with more detailed Finite Element Analysis (FEA). All critical input parameters of the LPTN are considered in detail for each layer of the stator, especially the contact resistances between the impregnation, liner, laminations and housing. Finally, a sensitivity analysis for each of the critical input parameters is provided. A maximum difference of 4%-for the highest temperature in the slot windings and the end windings-was found between the LPTN and the experimental data. Comparing the results from the LPTN and the FEA model, the maximum difference was 2% for the highest temperature in the slot windings and end windings. As for the LTPN sensitivity analysis, the thermal parameter with the highest sensitivity was found to be the liner-to-lamination contact resistance. The latter is often ignored in the literature, whereas its impact on temperature rise was found to be more significant than any other contact resistance within the stator.


ConferenceASME 2020 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems, InterPACK 2020
CityVirtual, Online

Bibliographical note

See NREL/CP-5400-77082 for preprint

NREL Publication Number

  • NREL/CP-5400-78873


  • Contact resistances
  • Electric motor
  • Fea
  • Lumped parameter network
  • Motor cooling
  • Sensitivity analysis
  • Thermal management


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