Ali AMMAR will defend her PhD on May 2nd, 2024 at 10:30AM.
Place : Université Claude Bernard Lyon 1, Bâtiment Gabriel Lippmann, Amphitheatre Gouy
Jury :
Rapporteurs :
M. Abdelkader BENABOU, Professeur des Universités, Université de Lille
Mme. Juliette SOULARD, Associate Professor, University of Warwick
Examinateurs :
M. Laurent DANIEL, Professeur des Universités, CentraleSupelec, Université Paris-Saclay
Mme. Marie-Ange RAULET, Maître de Conférence HDR, Université Claude Bernard Lyon 1
Encadrement :
M. Fabien SIXDENIER, Maître de Conférence HDR, Université Claude Bernard Lyon 1, Directeur de thèse
M. Charles JOUBERT, Professeur des Universités, Université Claude Bernard Lyon 1
Abstract :
Electrical machines are the focus of various recent regulations aiming at improving the energy consumption. Some of these regulations promote the multiplication of electrical vehicles hence of electrical motors, whereas other set minimum threshold for the efficiency of those motors. Consequently, improving the design and production of electrical machines is currently the target of much efforts from industrial actors and academics.
This work, entitled Development of methods of magnetic characterisation under rotational fields and thermal constraints, fits in these efforts as it aims to improve the understanding of the soft magnetic materials needed to build electrical machines. Its specificity is to combine two different types of magnetic characterisation which are seldom used together : under rotating fields and under varying temperature. Independently, each of these conditions impacts the behaviour of magnetic materials, and therefore the power loss and necessary magnetising power of applications.
The lack of studies of these combined phenomena comes from the difficulties associated to characterisation under rotating fields, whose results present a very poor repeatability across different laboratories. Additionally, the improvement of these measurement was slowed by the limitations of the vectorial hysteresis modelling. Indeed, working models would be in great need of trusted characterisation results, but as of now these results can mostly be used for direct comparison between materials. Nonetheless, the current context calls for a renewal of the studies in this field, with several laboratories currently working on characterisations under
rotating fields and high temperatures.
The present document reports the work undertaken at the Ampere Laboratory to implement this kind of characterisations. As such, it describes the main steps leading to the development of a test bench, from the conception phase to the actual implementation, which cover the generation, measurement and control of the rotating fields, data processing and heating of the sample. Given the current state of knowledge about measurement under rotating fields, special focus was paid to assess the performances of the test setup, based on comparison against measurements under alternating fields, simulation and measurements from other laboratories.
Finally, experimental results of magnetic material behaviour under rotation fields and varying temperatures are provided. The evolution of magnetic loss and observed anisotropy figures is quantified and compared to general properties of soft magnetic materials.
Keywords:
Magnetic characterisation, Magnetic Anisotropy, Electrical Steels, Temperature