scholarly journals A 5 MW direct-drive generator for floating spar-buoy wind turbine: Drive-train dynamics

2016 ◽  
Vol 231 (4) ◽  
pp. 744-763 ◽  
Author(s):  
Latha Sethuraman ◽  
Yihan Xing ◽  
Vengatesan Venugopal ◽  
Zhen Gao ◽  
Markus Mueller ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Drive Train ◽  
Simulation Tool ◽  
Dynamic Feedback ◽  
Direct Drive ◽  
Main Bearing ◽  
Fully Integrated ◽  
Wind Turbine System ◽  
Bearing Loads ◽  
Response Variables

This article proceeds with investigations on a 5 MW direct-drive floating wind turbine system (FWTDD) that was developed in a previous study. A fully integrated land-based direct-drive wind turbine system (WTDD) was created using SIMPACK, a multi-body simulation tool, to model the necessary response variables. The comparison of blade pitch control action and torque behaviour with a similar land-based direct-drive model in HAWC2 (an aero-elastic simulation tool) confirmed that the dynamic feedback effects can be ignored. The main shaft displacements, air-gap eccentricity, forces due to unbalanced magnetic pull (UMP) and the main bearing loads were identified as the main response variables. The investigations then proceed with a two-step de-coupled approach for the detailed drive-train analysis in WTDD and FWTDD systems. The global motion responses and drive-train loads were extracted from HAWC2 and fed to stand-alone direct-drive generator models in SIMPACK. The main response variables of WTDD and FWTDD system were compared. The FWTDD drive-train was observed to endure additional excitations at wave and platform pitch frequencies, thereby increasing the axial components of loads and displacements. If secondary deflections are not considered, the FWTDD system did not result in any exceptional increases to eccentricity and UMP with the generator design tolerances being fairly preserved. The bearing loading behaviour was comparable between both the systems, with the exception of axial loads and tilting moments attributed to additional excitations in the FWTDD system.

scholarly journals Analysis of Wind-Turbine Main Bearing Loads Due to Constant Yaw Misalignments over a 20 Years Timespan

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1768 ◽  
Author(s):  
Martin Cardaun ◽  
Björn Roscher ◽  
Ralf Schelenz ◽  
Georg Jacobs
Keyword(s):  
Wind Turbine ◽  
Wind Farms ◽  
Wake Flow ◽  
Energy Output ◽  
Main Bearing ◽  
Load Distributions ◽  
Wind Speed Distribution ◽  
Bearing Loads ◽  
Compact Design ◽  
Multi Body

The compact design of modern wind farms means that turbines are located in the wake over a certain amount of time. This leads to reduced power and increased loads on the turbine in the wake. Currently, research has been dedicated to reduce or avoid these effects. One approach is wake-steering, where a yaw misalignment is introduced in the upstream wind turbine. Due to the intentional misalignment of upstream turbines, their wake flow can be forced around the downstream turbines, thus increasing park energy output. Such a control scheme reduces the turbulence seen by the downstream turbine but introduces additional load variation to the turbine that is misaligned. Within the scope of this investigation, a generic multi body simulation model is simulated for various yaw misalignments. The time series of the calculated loads are combined with the wind speed distribution of a reference site over 20 years to investigate the effects of yaw misalignments on the turbines main bearing loads. It is shown that damage equivalent loads increase with yaw misalignment within the range considered. Especially the vertical in-plane force, bending and tilt moment acting on the main bearing are sensitive to yaw misalignments. Furthermore, it is found that the change of load due to yaw misalignments is not symmetrical. The results of this investigation are a primary step and can be further combined with distributions of yaw misalignments for a study regarding specific load distributions and load cycles.

scholarly journals Multibody dynamic modelling of a direct wind turbine drive train

2019 ◽  
Vol 44 (5) ◽  
pp. 519-547
Author(s):  
Saeed Asadi ◽  
Håkan Johansson
Keyword(s):  
Wind Turbine ◽  
Measurement Data ◽  
Dynamic Modelling ◽  
Simulation Software ◽  
Operating Conditions ◽  
Drive Train ◽  
Operational Experience ◽  
Main Bearing ◽  
Wide Range ◽  
Turbine Drive

Wind turbines normally have a long operational lifetime and experience a wide range of operating conditions. A representative set of these conditions is considered as part of a design process, as codified in standards. However, operational experience shows that failures occur more frequently than expected, the costlier of these including failures in the main bearings and gearbox. As modern turbines are equipped with sophisticated online systems, an important task is to evaluate the drive train dynamics from online measurement data. In particular, internal forces leading to fatigue can only be determined indirectly from other locations’ sensors. In this contribution, a direct wind turbine drive train is modelled using the floating frame of reference formulation for a flexible multibody dynamics system. The purpose is to evaluate drive train response based on blade root forces and bedplate motions. The dynamic response is evaluated in terms of main shaft deformation and main bearing forces under different wind conditions. The model was found to correspond well to a commercial wind turbine system simulation software (ViDyn).

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