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19th Drive Train Technology Conference (ATK 2021) : 9th-11th March 2021, Aachen, Germany / editorial board: Prof. Dr.-Ing. Georg Jacobs, Sebastian Stein, M.Sc. 19. Antriebstechnisches Kolloquium = 19th Drive Train Technology Conference, ATK 2021, online, 9 Mar 2021 - 11 Mar 2021; [Bristol] : IOP Publishing, IOP conference series. Materials science and engineering 1097, 012007, 1-13 (2021). doi:10.1088/1757-899X/1097/1/012007, Published by IOP Publishing, [Bristol]

Doubly fed induction generators are widely used in wind turbines in the field. The main advantage is the significantly lower cost of the partial scale power converter compared to the full scale power converter. Converter faults in wind turbines lead to significant generator torque excitations that lead to dynamic loads in the drivetrain. Dynamic loads and changing rotational speeds can lead to gearbox damages. The generator torque excitations have the highest influence on the high speed shaft torque due to the coupling to the generator. Gearbox damages occur mainly on the components of the high speed shaft. Thus, in this paper the influence of a converter fault in a wind turbine with doubly fed induction generator on the high speed shaft component damages is investigated. It is shown that the converter fault can induce dynamic torque excitations with a maximum increase to around 2.5 times rated torque. Due to the resulting dynamic gearbox loading the safety against scuffing in the high speed gear stage decreases by maximum 19 percent. The smearing risk in the high speed shaft bearings increases to around 2 times the value during rated power production.

19th Drive Train Technology Conference (ATK 2021) : 9th-11th March 2021, Aachen, Germany / editorial board: Prof. Dr.-Ing. Georg Jacobs, Sebastian Stein, M.Sc. 19. Antriebstechnisches Kolloquium = 19th Drive Train Technology Conference, ATK 2021, online, 9 Mar 2021 - 11 Mar 2021; [Bristol] : IOP Publishing, IOP conference series. Materials science and engineering 1097, 012001 pp. (2021). doi:10.1088/1757-899X/1097/1/012001, Published by IOP Publishing, [Bristol]

19th Drive Train Technology Conference (ATK 2021) 9th-11th March 2021, Aachen, Germany 19. Antriebstechnisches Kolloquium = 19th Drive Train Technology Conference, ATK 2021, online, 9 Mar 2021 - 11 Mar 2021; London [u.a.] : Institute of Physics, IOP Conference Series: Materials Science and Engineering 1097, 012019, 1-12 (2021). doi:10.1088/1757-899X/1097/1/012019, Published by Institute of Physics, London [u.a.]

19th Drive Train Technology Conference (ATK 2021) : 9th-11th March 2021, Aachen, Germany / editorial board: Prof. Dr.-Ing. Georg Jacobs, Sebastian Stein, M.Sc. 19. Antriebstechnisches Kolloquium = 19th Drive Train Technology Conference, ATK 2021, online, 9 Mar 2021 - 11 Mar 2021; [Bristol] : IOP Publishing, IOP conference series. Materials science and engineering 1097, 012022, 1-12 (2021). doi:10.1088/1757-899X/1097/1/012022, Published by IOP Publishing, [Bristol]

19th Drive Train Technology Conference (ATK 2021) 9th-11th March 2021, Aachen, Germany 19. Antriebstechnisches Kolloquium, ATK 2021, online, 9 Mar 2021 - 11 Mar 2021; London [u.a.] : Institute of Physics 012008, 1-12 (2021). doi:10.1088/1757-899X/1097/1/012008, Published by Institute of Physics, London [u.a.]

TORQUE 2020, online, 28 Sep 2020 - 2 Oct 2020; Journal of physics / Conference series 1618, 022060 (2020). doi:10.1088/1742-6596/1618/2/022060 special issue: "The Science of Making Torque from Wind (TORQUE 2020)", Published by IOP Publ., Bristol

Considering building a wind farm, a quarter of the initial investment cost is accounted for planning, construction, and project preparation. Some of those expenses can be reduced within the project concept phase. The wind farm layout is one of the common aspects being optimized. Commonly, wind turbines are placed such that wake losses are minimal. However, this might lead to long access roads. The cost of a gravel road is estimated to be 75 €/m. In this paper, an optimization problem considering access roads is developed. Two methods are investigated to determine the influence of the access roads on a wind farm layout optimization. A case study with seven wind turbines is set up. The layout is optimized such that the LCOE is minimal. One method examines a wind farm with nearby existing roads. This method results in a reduction of road costs by 9 000€ while the AEP suffers a loss of 0.134 %. The second method neglects existing roads and develops a new access road network. Comparing an optimized wind farm layout without considering the access roads to an optimization that included the access leads to 22 000 € fewer road investment costs and a loss of AEP of 0.238 %. Those changes seem marginal but indicate a possible gain for large scale wind farms.

Journal of physics / Conference series Conference series [...] 1452, 012052 - (2020). doi:10.1088/1742-6596/1452/1/012052, Published by IOP Publ.40022, Bristol

Journal of physics / Conference Series Conference Series 1102, 012024 - (2018). doi:10.1088/1742-6596/1102/1/012024, Published by IOP Publ., Bristol

Wake Conference, Uppsala, Sweden, 22 May 2019 - 24 May 2019; Journal of physics / Conference series 1256, 012014 (2019). doi:10.1088/1742-6596/1256/1/012014 special issue: "Wake Conference 2019 : 22-24 May 2019, Visby, Sweden / Stefan Ivanell, Andrew Barney, Maria Klemm and Jens Nørkær Sørensen" (978-1-5108-9181-4), Published by IOP Publ., Bristol

International Conference on Design, Energy, Materials and Manufacture 24-25 October 2018, Bali, Indonesia International Conference on Design, Energy, Materials and Manufacture, Bali, Indonesia, 24 Oct 2018 - 25 Oct 2018; London [u.a.] : Institute of Physics, IOP conference series / Materials science and engineering Materials science and engineering 539, 012030 pp. (2019). doi:10.1088/1757-899X/539/1/012030, Published by Institute of Physics, London [u.a.]

The presented paper introduces simulative method for the determination of load and pressure distribution in the main roller bearings in multi-MW wind turbines. This method has been developed using the example of a generic 6 MW research wind turbine (WT). The investigated drive train comprises of a main gearbox and is mounted with a four point suspension. The fixed rotor bearing is a spherical roller bearing and the floating rotor bearing is a cylindrical roller bearing. The load and pressure distribution is determined by finite element (FE) simulation under consideration of real hub loads and elastic surroundings. The hub loads have been calculated using Multibody Simulation. Three different rotor bearing models are introduced, which consider FE contact conditions, macro-geometry, stiffness and rolling element profile. The developed method is transferable to different rolling bearing types and can be used to improve bearing load and pressure distribution in multi-MW WTs under consideration of elastic surroundings (main shaft, frame and bearing housing).

Premature bearing outages at the planetary and high speed shaft stage of gearboxes are responsible for long down time periods of wind turbines [1, 2]. In order to prevent premature bearing outages against certain failure mechanisms, a new robustness test procedure for original-sized WT gearbox bearings is developed within the project WT-Bearing Center.NRW. The BRT serves to qualify bearings for a damage-free operation over the entire service life [3]. It combines a fatigue load spectrum and also additional special load events [4]. This paper describes the analysis of wind turbine loads during different operation conditions and the definition of special load events, based on this analysis. The aim of including special loads to the BRT is to consider the complex real bearing loads within the test procedure as precisely as possible.

Journal of physics / Conference Series Conference Series 1065, 042050 - (2018). doi:10.1088/1742-6596/1065/4/042050, Published by IOP Publ., Bristol

Journal of physics / Conference Series 1037/042026, 1 - 7 (2018). doi:10.1088/1742-6596/1037/4/042026, Published by IOP Publ., Bristol

Wake Conference 2017 : 30 May to 1 June 2017, Visby, Sweden Wake Conference, Visby, Sweden, 30 May 2017 - 1 Jun 2017; Bristol : IOP Publ., Journal of Physics Conference Series 854, 012038 pp. (2017). doi:10.1088/1742-6596/854/1/012038, Published by IOP Publ., Bristol

This contribution presents a model interface of a wind turbine generator to represent the reciprocal effects between the mechanical and the electromagnetic system. Therefore, a multi-body-simulation (MBS) model in Simpack is set up and coupled with a quasi-static electromagnetic (EM) model of the generator in Matlab/Simulink via co-simulation. Due to lack of data regarding the structural properties of the generator the modal properties of the MBS model are fitted with respect to results of an experimental modal analysis (EMA) on the reference generator. The used method and the results of this approach are presented in this paper. The MB S model and the interface are set up in such a way that the EM forces can be applied to the structure and the response of the structure can be fed back to the EM model. The results of this cosimulation clearly show an influence of the feedback of the mechanical response which is mainly damping in the torsional degree of freedom and effects due to eccentricity in radial direction. The accuracy of these results will be validated via test bench measurements and presented in future work. Furthermore it is suggested that the EM model should be adjusted in future works so that transient effects are represented.

Wind turbines (WT) are steadily growing in size to increase their power production, which also causes increasing loads acting on the turbine's components. At the same time large structures, such as the blades and the tower get more flexible. To minimize this impact, the classical control loops for keeping the power production in an optimum state are more and more extended by load alleviation strategies. These additional control loops can be unified by a multiple-input multiple-output (MIMO) controller to achieve better balancing of tuning parameters. An example for MIMO control, which has been paid more attention to recently by wind industry, is Model Predictive Control (MPC). In a MPC framework a simplified model of the WT is used to predict its controlled outputs. Based on a user-defined cost function an online optimization calculates the optimal control sequence. Thereby MPC can intrinsically incorporate constraints e.g. of actuators. Turbine models used for calculation within the MPC are typically simplified. For testing and verification usually multi body simulations, such as FAST, BLADED or FLEX5 are used to model system dynamics, but they are still limited in the number of degrees of freedom (DOF). Detailed information about load distribution (e.g. inside the gearbox) cannot be provided by such models. In this paper a Model Predictive Controller is presented and tested in a co-simulation with SlMPACK, a multi body system (MBS) simulation framework used for detailed load analysis. The analysis are performed on the basis of the IME6.0 MBS WT model, described in this paper. It is based on the rotor of the NREL 5MW WT and consists of a detailed representation of the drive train. This takes into account a flexible main shaft and its main bearings with a planetary gearbox, where all components are modelled flexible, as well as a supporting flexible main frame. The wind loads are simulated using the NREL AERODYN v13 code which has been implemented as a routine to SlMPACK. This modeling approach allows to investigate the nonlinear behavior of wind loads and nonlinear drive train dynamics. Thereby the MPC's impact on specific loads and effects not covered by standard simulation tools can be assessed and investigated. Keywords. wind turbine simulation, model predictive control, multi body simulation, MIMO, load alleviation