Influence of thermal-mechanical stress on the insulation system of a low voltage electrical machine

• Autorzy: Yang Liguo , Pauli Florian , Hameyer Kay

Identyfikatory

DOI

10.24425/aee.2021.136064

• Języki publikacji: EN

Abstrakty

EN

Varying ohmic loss in the winding of electrical machines, which are operated atvarious operating points, results in temperature changes during operation. Particularly, when the temperature is varying dynamically, the insulation system suffers from repeated thermal-mechanical stress, since the thermal expansion coefficients of the insulating materials and copper conductors are different. For the appropriate design of an insulation system, the effect of thermal-mechanical stress must be known. In the present work, motorettes are subjected to repeated thermal cycles. The expected lifetime is estimated and compared to the life time which is achieved by applying a lifetime-model which only considers thermal aging while ignoring thermal-mechanical stress effects. In addition, the hotspot temperature is simulated, the lifetime at the hotspot is estimated as the worst case. As expected, the results indicate that the thermal-mechanical stress plays a significant role during dynamic thermal aging of the winding insulation system. To better understand the thermal-mechanical stress effect, the resulting thermal-mechanical stress in a single wire is analyzed by the finite element method. A preliminary analysis of the aging mechanism of materials due to cyclic thermal-mechanical stress is performed with the theory of material fatigue.

Słowa kluczowe

EN

insulation system; material fatigue; thermal-mechanical stress

PL

system izolacji; zmęczenie materiału; naprężenie cieplno-mechaniczne

• Wydawca: Polish Academy of Sciences, Committee on Electrical Engineering
• Czasopismo: Archives of Electrical Engineering
• Rocznik: 2021
• Tom: Vol. 70, nr 1
• Strony: 233--244
• Opis fizyczny: Bibliogr. 15 poz., rys., tab., wz.

Twórcy

autor

Yang Liguo

• Institute of Electrical Machines (IEM), RWTH Aachen University, Schinkelstraße 4, 52062 Aachen, Germany

• https://orcid.org/0000-0001-5746-7486

autor

Pauli Florian

• Institute of Electrical Machines (IEM), RWTH Aachen University, Schinkelstraße 4, 52062 Aachen, Germany

autor

Hameyer Kay

• Institute of Electrical Machines (IEM), RWTH Aachen University, Schinkelstraße 4, 52062 Aachen, Germany

Bibliografia

• 1] Stone G. C., Boulter E. A., Culbert I., Dhirani H., Electrical insulation for rotating machines: design, evaluation, aging, testing, and repair, John Wiley & Sons (2004).
• [2] Rothe R., Hameyer K., Life expectancy calculation for electric vehicle traction motors regarding dynamic temperature and driving cycles, 2011 IEEE International Electric Machines and Drives Conference (IEMDC), Niagara Falls, ON, Canada, pp. 1306–1309 (2011).
• [3] Huang Z., Modeling and testing of insulation degradation due to dynamic thermal loading of electrical machines, Licentiate Thesis, Lund University, Lund (2017).
• [4] Chen W., Nelson C., Thermal stress in bonded joints, IBM Journal of Research and Development, vol. 23, no. 2, pp. 179–188 (1979).
• [5] Arrhenius S., On the heat of dissociation and the influence of temperature on the degree of dissociation of the electrolytes, Zeitschrift für Physikalische Chemie (in German, Über die Dissociationswärmeund den Einfluss der Temperatur auf den Dissociationsgrad der Elektrolyte), vol. 4, no. 1, pp. 96–116 (1889).
• [6] Dakin T. W., Electrical insulation deterioration treated as a chemical rate phenomenon, Transactionsof the American Institute of Electrical Engineers, vol. 67, no. 1, pp. 113–122 (1948).
• [7] Ruf A., Pauli F., Schröder M., Hameyer K., Lifetime modelling of non-partial discharge resistant insulation systems of electrical machines in dynamic load collectives, e & i Elektrotechnik und Informationstechnik (in German, Lebensdauermodellierung von nicht-teilentladungsresistenten isoliersystemen elektrischer maschinen in dynamischen lastkollektiven), vol. 135, no. 2, pp. 131–144 (2018).
• [8] Pauli F., Schröder M., Hameyer K., Design and evaluation methodology for insulation systems of low voltage drives with preformed coils, 2019 9th International Electric Drives Production Conference (EDPC), Esslingen, Germany, pp. 1–7 (2019).
• [9] Madonna V., Giangrande P., Lusuardi L., Cavallini A., Gerada C., Galea M., Thermal overload and insulation aging of short duty cycle, aerospace motors, IEEE Transactions on Industrial Electronics,vol. 67, no. 4, pp. 2618–2629 (2019).
• [10] Sciascera C., Galea M., Giangrande P., Gerada C., Lifetime consumption and degradation analysis of the winding insulation of electrical machines, 2016 8th IET International Conference on Power Electronics, Machines and Drives (PEMD), Glasgow, UK, pp. 1–5 (2016).
• [11] IEC 60505, Evaluation and qualification of electrical insulation systems (2011).
• [12] Ruf A., Paustenbach J., Franck D., Hameyer K., A methodology to identify electrical ageing of winding insulation systems, 2017 IEEE International Electric Machines and Drives Conference (IEMDC), Miami, FL, USA, pp. 1–7 (2017).
• [13] Pauli F., Ruf A., Hameyer K., Low voltage winding insulation systems under the influence of high du/dtslew rate inverter voltage, Archives of Electrical Engineering, vol. 69, no. 1, pp. 187–202 (2020).
• [14] IEC 60034–18–41, Rotating electrical machines – Part 18–41: Partial discharge free electrical insulation system (Type I) used in rotating electrical machines fed from voltage converters – Qualification and quality control tests (2014).
• [15] Nikolova G., Ivanova J., Interfacial shear and peeling stresses in a two-plate structure subjected to monotonically increasing thermal loading, Journal of Theoretical and Applied Mechanics, vol. 51 (2013).

Uwagi

Opracowanie rekordu ze środków MNiSW, umowa Nr 461252 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2021).