Magnetomechanische Effekte in rotierenden elektrischen Maschinen : Einfluss von mechanischer Spannung auf die magnetischen Eigenschaften von Elektroband

Karthaus, Jan; Hameyer, Kay (Thesis advisor); Hanitsch, Rolf (Thesis advisor); Jacobs, Georg (Thesis advisor)

Düren : Shaker (2020)
Book, Dissertation / PhD Thesis

In: Aachener Schriftenreihe zur elektromagnetischen Energiewandlung 39
Page(s)/Article-Nr.: xi, 180 Seiten : Illustrationen, Diagramme

Dissertation, RWTH Aachen University, 2020

Abstract

The demand for high performance with simultaneous reduction of the installation space and increase of the machine efficiency requires the use of electrical high speed machines. Along with the high circumferential speeds, high centrifugal forces result in high static and cyclical mechanical loads in the rotor. The mechanical loads generated during the operation of the electrical machine overlap with the mechanical preloads from the production and manufacture of the rotor or the rotor lamination stack. Depending on the manufacturing, processing and operating point of the machine, different mechanical loads are generated in stator and rotor core lamination stacks. In the design of electrical machines, the influence of mechanical stress on the magnetic properties of the electrical steel strip material has so far hardly been taken into account or not at all. The mutual influence between mechanical stress and magnetic properties is called the Villari effect. The question of a uniform modelling methodology that takes into account the conditions during operation of the electrical machine remains unanswered. In this case, it must address the question of how the magnetomechanical effect affects local and global machine characteristics during operation of the electric machine and how a machine design can specifically influence these variables. In this dissertation, it is shown that the electrical steel strip materials used in electrical machines react sensitively to static or cyclic external mechanical loads at different frequencies. In order to study the effects of static mechanical stress on electrical steel sheet grades, material measurements are carried out in this thesis using a panel meter with which mechanically stressed samples are magnetically characterized. A measuring method is also developed and presented which determines the relationship between cyclic mechanical stress, which initiates a fatigue process in the electrical steel material, and magnetic properties. The results of the measurements will be analysed with regard to the effects in the electrical machine (e.g. frequency dependency). The subsequent modelling integrates the knowledge gained from this analysis and thus enables its use in the electromagnetic simulation. A correlation between static mechanical stress and magnetic material behaviour could be proven and modelled for electrical steel sheet considered as an example. A significant effect occurs for cyclically stressed samples for high mechanical stress levels already at low numbers of cycles. With the help of the developed modelling method the effects in the electrical machines could be proven by means of mechanical and electromagnetic simulation.

Institutions

• Chair of Electromagnetic Energy Conversion [614410]