Inverse Thermal Analysis of Electrical Machines

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Volume Title

School of Electrical Engineering | Doctoral thesis (article-based) | Defence date: 2019-07-26
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Authors

Date

2019

Department

Sähkötekniikan ja automaation laitos
Department of Electrical Engineering and Automation

Major/Subject

Mcode

Degree programme

Language

en

Pages

89 + app. 45

Series

Aalto University publication series DOCTORAL DISSERTATIONS, 103/2019

Abstract

This thesis focuses on the inverse thermal process of determining power losses of electrical machines from temperature measurements. The feasibility of this endeavour is investigated and the inverse mapping of losses with analytical and numerical thermal models of a 37 kW cage induction motor are demonstrated. Accurate lumped thermal networks as well as 2D and 3D finite element models of a 37 kW motor are built as forward thermal models for this purpose. Attention is given to managing error in measurement so that the temperature-to-source mapping can be accurate. The inverse mapping was achieved with two methods - least squares and conjugate gradient. The results of the inverse mapping indicate that inverse thermal approaches hold promise in estimating losses in machine domains where direct measurements are cumbersome, such as the stator yoke or tooth regions. Lumped and distributed loss components could be recovered reliably using both inverse methods. Furthermore, a water-cooled calorimeter was designed and built to measure the total power loss of the induction motor. With only a few measured temperatures of the motor, the inverse thermal process is able to segregate the total losses into its constituent components.

Description

Supervising professor

Arkkio, Antero, Prof., Aalto University, Department of Electrical Engineering and Automation, Finland

Keywords

calorimetry, electrical motor, heat transfer, inverse thermal problem

Other note

Parts

  • [Publication 1]: Devi Geetha Nair, Antero Arkkio. Inverse Thermal Modelling to Determine Power Losses in Induction Motor. IEEE Transactions on Magnetics, 2017, Volume 53, No. 6, pp. 1-4.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-201705033730
    DOI: 10.1109/TMAG.2017.2661381 View at publisher
  • [Publication 2]: Devi Geetha Nair, Antero Arkkio. Verification of Loss Segregation in Electrical Machines through Inverse Thermal Modelling. International Journal of Applied Electromagnetics and Mechanics, 2019, Volume 59, No. 1, pp. 227-233,
    DOI: 10.3233/JAE-171041 View at publisher
  • [Publication 3]: Devi Geetha Nair, Paavo Rasilo, Antero Arkkio. Sensitivity Analysis of Inverse Thermal Modelling to Determine Power Losses in Electrical Machines. IEEE Transactions on Magnetics, 2018, Volume 54, No. 11, pp. 1-5. Full text in Acris Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-201811025603.
    DOI: 10.1109/TMAG.2018.2853084 View at publisher
  • [Publication 4]: Devi Geetha Nair, Shayan Daryabin, Steven Jannasch, Ari Haavisto, Antero Arkkio. Design of water-cooled calorimeter for electric motor’s power loss measurement. In International Conference on Electrical Machines ICEM, Alexandroupolis, pp. 1142-1148, September 2018.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-201901141160
    DOI: 10.1109/ICELMACH.2018.8507232 View at publisher
  • [Publication 5]: Devi Geetha Nair, Antero Arkkio, Ari Haavisto. Power loss segregation in electrical machines through calorimetry and inverse thermal modelling. Submitted to IET Electric Power Applications, February 2019.
  • [Errata file]: Errata of P3, P4, P5

Citation

Permanent link to this item

https://urn.fi/URN:ISBN:978-952-60-8578-4

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[diss] Sähkötekniikan korkeakoulu / ELEC