The demand for increasing nominal power in wind energy leads - especially in gearless systems - to significantly increasing generator dimensions. The only way to realize the increased dimensions is by using lightweight construction methods. This often leads to a reduction of the component stiffness, which requires a more intensive consideration of the structural dynamics [1]. This is in particular true since the wind turbine exposes the generator to more complex excitations compared to other locations as in conventional power plants. Research shows that the stochastic loading of the wind turbines in certain situations can lead to resonances in the generator (see [2][3]). The named research focuses on effects acting on the generator, caused by the wind turbine. The inverse impact from the generator to the wind turbine has not yet been investigated, though two-way coupling effects in wind turbines are of significant importance for the calculated load levels [4]. The influence on short-term load levels leads to the assumption that the calculated service lifetime based on fatigue can also be affected. Additionally, the dependency of the interactions on the choice of design is unknown. Furthermore, using simulation based analysis methods, the results strongly depend on the chosen model depth [5].

Considering these aspects, the aim of this research is to be able to simulate vibrational interactions between the generator magnetic field and the wind turbine combining the analysis of service lifetime, design dependency and modelling depth. As a result, the minimum model depth required to calculate the service life of the wind turbine under consideration of the generator will be identified. This offers the possibility of adapting the generator design in future more closely to the requirements of the wind turbine. At the same time, a better exploitation of the scope for design becomes possible, which promises a higher reliability of the generator and the wind turbine as well as a more cost-efficient design of the overall system.

[1] Z. Zhang, A. Chen, A. Matveev, R. Nilssen, and A. Nysveen, “High-power Generators for Offshore Wind Turbines,” Energy Procedia, vol. 35, no. 1876, pp. 52–61, 2013.

[2] M. Valavi, “Mostafa Valavi Magnetic Forces and Vibration in Wind Power Generators Analysis of Fractional-Slot Low-Speed PM Machines with Concentrated Windings,” Norwegian University of Science and Technology, 2015.

[3] D. Matzke, S. Rick, S. Hollas, R. Schelenz, G. Jacobs, and K. Hameyer, “Coupling of electromagnetic and structural dynamics for a wind turbine generator,” J. Phys. Conf. Ser., vol. 753, no. 8, p. 82034, Sep. 2016.

[4] M. Andre, M. Péntek, K.-U. Bletzinger, and R. Wüchner, “Aeroelastic simulation of the wind-excited torsional vibration of a parabolic trough solar collector,” J. Wind Eng. Ind. Aerodyn., vol. 165, no. October 2016, pp. 67–78, 2017.

[5] J. Gallego-Calderon and A. Natarajan, “Assessment of wind turbine drive-train fatigue loads under torsional excitation,” Eng. Struct., vol. 103, pp. 189–202, Nov. 2015.