Effect of Manufacturing Processes on Electrical Machine’s Performance

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School of Electrical Engineering | Doctoral thesis (article-based) | Defence date: 2020-09-04
Degree programme
62 + app 106
Aalto University publication series DOCTORAL DISSERTATIONS, 111/2020
This thesis focuses on the effects of manufacturing processes on electrical machine performance. The effects of cutting, welding, and shrink fitting are considered and the effects of cutting are studied more thoroughly in this thesis. A 37 kW induction motor is used as a test machine.  A cutting loss model is proposed based on Epstein frame measurements of non-oriented strips of different cutting lengths. The loss model is validated with core loss measurements of the strips and stators manufactured with wire electric discharge machining and laser cutting. The proposed cutting loss model is also evaluated with grain-oriented strips cut with punching, water jet and laser cutting. Furthermore, two different finite element approaches based on higher and mixed-order elements are proposed for computationally efficient modelling of the cutting effects. The effect of welding is analysed with measurements of the ring cores of loose and welded sheets of stator laminations. In addition, stator core losses are measured with and without the frame to quantify the shrink fitting effects. Different approaches are proposed to include the effects of welding and shrink fitting in the finite element analysis of an electrical machine. A dummy blocked rotor test setup is designed and manufactured to measure the effect of different manufacturing processes on the stator core losses. As a result of manufacturing processes, the stator core losses of the induction machine increased by 23 % at the rated flux (400 V, 50 Hz). The contributions of cutting, welding, and shrink fitting are observed to be about 10 %, 7 %, and 6 % respectively. The presented loss models are found to predict the corresponding effects of manufacturing processes accurately.
Supervising professor
Belahcen, Anouar, Prof., Aalto University, Dept. of Electrical Engineering and Automation., Finland
Thesis advisor
Arkkio, Antero, Prof., Aalto University, Finland
Lehikoinen, Antti, Dr., Smeklab, Finland
core loss, cutting, electrical machine, manufacturing effect, shrink fitting, welding
Other note
  • [Publication 1]: Ravi Sundaria, Antti Lehikoinen, Antti Hannukainen, Antero Arkkio, Anouar Belahcen. Mixed-Order Finite Element Modeling of Magnetic Material Degradation Due to Cutting. IEEE Transactions on Magnetics, Volume 54, Issue 6, pp. 1-8, June 2018.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-201808014057
    DOI: 10.1109/TMAG.2018.2811385 View at publisher
  • [Publication 2]: Ravi Sundaria, Devi Geetha Nair, Antti Lehikoinen, Antero Arkkio, Anouar Belahcen. Effect of Laser Cutting on Core Losses in Electrical Machines - Measurements and Modeling. IEEE Transactions on Industrial Electronics, Volume 67, Issue 9, pp. 7354-7363, September 2020.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202006254043
    DOI: 10.1109/TIE.2019.2942564 View at publisher
  • [Publication 3]: Ravi Sundaria, Andries Daem, Osaruyi Osemwinyen, Antti Lehikoinen, Peter Sergeant, Antero Arkkio, Anouar Belahcen. Effects of Stator Core Welding on an Induction Machine – Measurements and Modeling. Journal of Magnetism and Magnetic Materials, Volume 499, April 2020.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202003062432
    DOI: 10.1016/j.jmmm.2019.166280 View at publisher
  • [Publication 4]: Ravi Sundaria, Antti Lehikoinen, Antero Arkkio, Anouar Belahcen. Effects of Manufacturing Processes on Core Losses of Electrical Machines. Accepted for publication in IEEE Transactions on Energy Conversion, pp. 1-10, May 2020.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202006254042
    DOI: 10.1109/TEC.2020.2999528 View at publisher
  • [Publication 5]: Ravi Sundaria, Antti Lehikoinen, Antti Hannukainen, Antero Arkkio. Higher-Order Finite Element Modeling of Material Degradation Due toCutting. In 2017 IEEE International Electric Machines and Drives Conference (IEMDC), Miami, Florida, USA, pp. 1-6, May 2017.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-201809064952
    DOI: 10.1109/IEMDC.2017.8002278 View at publisher
  • [Publication 6]: Ravi Sundaria, Ahmed Hemeida, Antero Arkkio, Andries Daem, Peter Sergeant, Anouar Belahcen. Effect of Different Cutting Techniques on Magnetic Properties of Grain Oriented Steel Sheets and Axial Flux Machines. In IECON 2019 - 45th Annual Conference of the IEEE Industrial Electronics Society, Lisbon, Portugal, pp. 1-6, October 2019.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202006013445
    DOI: 10.1109/IECON.2019.8926876 View at publisher