Improving Wind Turbine Drivetrain Reliability Using a Combined Experimental, Computational, and Analytical Approach

Guo, Yi; Bergua, Roger; Dam, Jeroen van; Jové, Jordi; Campbell, Jon

doi:10.1115/detc2014-35169

Cited by 5 publications

(7 citation statements)

References 10 publications

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“…Publicly available, peer‐reviewed literature comparing the design trade‐offs associated with these two drivetrain architectures is scarce. Industry reports have claimed that four‐point suspensions are more costly by having the additional main bearing, but that designs have advantages in the isolation of non‐torque loads from the gearbox . Test results published through the Gearbox Reliability Collaborative , which uses a three‐point suspension drivetrain in its analysis, indicate that such non‐torque loads should not affect tooth contact patterns in the intermediate and high‐speed stage in a manner that would decrease gearbox life.…”

Section: Introductionmentioning

confidence: 99%

A systems engineering analysis of three‐point and four‐point wind turbine drivetrain configurations

et al. 2016

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This study compares the impact of drivetrain configuration on the mass and capital cost of a series of wind turbines ranging from 1.5 MW to 5.0 MW power ratings for both land-based and offshore applications. The analysis is performed with a new physics-based drivetrain analysis and sizing tool, Drive Systems Engineering (DriveSE), which is part of the Wind-Plant Integrated System Design & Engineering Model. DriveSE uses physics-based relationships to size all major drivetrain components according to given rotor loads simulated based on International Electrotechnical Commission design load cases. The model's sensitivity to input loads that contain a high degree of variability was analyzed. Aeroelastic simulations are used to calculate the rotor forces and moments imposed on the drivetrain for each turbine design. DriveSE is then used to size all of the major drivetrain components for each turbine for both three-point and four-point configurations. The simulation results quantify the trade-offs in mass and component costs for the different configurations. On average, a 16.7% decrease in total nacelle mass can be achieved when using a three-point drivetrain configuration, resulting in a 3.5% reduction in turbine capital cost. This analysis is driven by extreme loads and does not consider fatigue. Thus, the effects of configuration choices on reliability and serviceability are not captured. However, a first order estimate of the sizing, dimensioning and costing of major drivetrain components are made which can be used in larger system studies which consider trade-offs between subsystems such as the rotor, drivetrain and tower. INTRODUCTIONThree-point and four-point suspensions, which refer to wind turbine drivetrain configurations with either one or two main bearings, respectively, are the most common wind turbine drivetrain architectures. In the three-point suspension configuration, the rotor is rigidly connected to the main shaft, which is supported by a single main bearing near the rotor. A shrink disk typically connects the downwind side of the shaft to the low-speed stage of the gearbox. The gearbox is supported by two torque arms that are connected to the bedplate elastically. These two torque arms, along with the single main bearing, provide a total of three points of support. Commercial wind turbines that utilize this configuration include the General Electric GE 1.5 MW, Siemens SWT108 2.3 MW, Nordex N117 2.4 MW and Vestas V112 3 MW. 1 Four-point suspension configurations, sometimes referred as two-main-bearing suspension configuration, place an additional main bearing near the down-wind side of the main shaft with the intent of isolating any non-torque rotor loads upwind of the gearbox. Non-torque rotor loads are the non-torsional loads transmitted from the rotor blades to the drivetrain. These non-torque loads can affect gearbox reliability significantly by causing uneven loads among planetary gears and reducing bearing life. 2 The design protects the gearbox from non-torque loads but, at the same time, suc...

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Section: Introductionmentioning

confidence: 99%

A systems engineering analysis of three‐point and four‐point wind turbine drivetrain configurations

et al. 2016

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“…The first configuration (referred to here as a centered support) features two main-bearing rows widely spaced on either side of the hub, typically transferring the non-torque loads to a stationary internal mounting or extended frame. This configuration is representative of the Alstom ECO100 geared (Guo et al, 2014(Guo et al, , 2015 and the GE Haliade direct-drive (GE, 2021) turbines. The second configuration (referred to here as an overhung support) features two main-bearing rows more closely spaced together both downwind of the hub, transferring the non-torque loads in some cases to a stationary internal frame representative of many newer direct-drive turbines (Gaertner et al, 2020) while in others transferring them to a bearing housing representative of many geared turbines (Demtröder et al, 2019).…”

Section: Main-bearing Configurations and Analytical Modellingmentioning

confidence: 99%

“…In conjunction with these developments, advances in rotor support technology are taking place that support and transfer the majority if not all rotor loads other than torque to the bedplate, isolating the rest of the drivetrain from these effects. Geared drivetrains increasingly are supported by two main-bearings within an integrated housing for example by Vestas (Demtröder et al, 2019;Nejad et al, 2021), while a few geared and some direct-drives use an "inverting" configuration, in which the entire hub rotates about a stationary internal mounting with one more more main-bearings (Guo et al, 2014(Guo et al, , 2015van Dam, 2020;Torsvik et al, 2018;Hart et al, 2020;Nejad and Torsvik, 2021). Such technology is currently implemented in Siemens Gamesa and GE direct-drive turbines, among others.…”

Section: Introductionmentioning

confidence: 99%

Impacts of wind field characteristics and non-steady deterministic wind events on time varying main-bearing loads

Hart¹,

Stock²,

Elderfield³

et al. 2022

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Abstract. This work considers the characteristics and drivers of the loads experienced by wind turbine main-bearings. Simplified load response models of two different hub and main-bearing configurations are presented, representative of both inverting direct-drive and four-point mounted geared drivetrains. The influences of deterministic wind field characteristics, such as wind speed, shear, yaw offset and veer, on the bearing load patterns are then investigated for similarity scaled 5, 7.5 and 10 MW reference wind turbine models. Main-bearing load response in cases of deterministic gusts and extreme changes in wind direction are also considered for the 5 MW model. Perhaps surprisingly, veer is identified as an important driver of main-bearing load fluctuations. Upscaling results indicate that similar behaviour holds as turbines become larger, but with mean loads and load fluctuation levels increasing at least cubically with the turbine rotor radius. Strong links between turbine control and main-bearing load response are also observed.

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“…The uncertainty in bearing stiffness estimation can also contribute the difference seen between the computational model and the other approaches. The detailed discussion on model sensitivity tests is included by Guo et al …”

Section: Addressing Non‐torque Loads Outside the Gearboxmentioning

confidence: 99%

Improving wind turbine drivetrain designs to minimize the impacts of non-torque loads

et al. 2014

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Non-torque loads induced by the wind turbine rotor overhang weight and aerodynamic forces can greatly affect drivetrain loads and responses. If not addressed properly, these loads can result in a decrease in gearbox component life. This work uses analytical modeling, computational modeling and experimental approaches to evaluate two distinct drivetrain designs that minimize the effects of non-torque loads on gearbox reliability: a modified three-point suspension drivetrain studied by the National Renewable Energy Laboratory (NREL) Gearbox Reliability Collaborative (GRC) and the Pure Torque® drivetrain developed by Alstom. In the original GRC drivetrain, the unequal planetary load distribution and sharing were present and they can lead to gear tooth pitting and reduce the lives of the planet bearings. The NREL GRC team modified the original design of its drivetrain by changing the rolling element bearings in the planetary gear stage. In this modified design, gearbox bearings in the planetary gear stage are anticipated to transmit non-torque loads directly to the gearbox housing rather than the gears. Alstom's Pure Torque drivetrain has a hub support configuration that transmits non-torque loads directly into the tower rather than through the gearbox as in other design approaches. An analytical model of Alstom's Pure Torque drivetrain provides insight into the relationships among turbine component weights, aerodynamic forces and the resulting drivetrain loads. In Alstom's Pure Torque drivetrain, main shaft bending loads are orders of magnitude lower than the rated torque and hardly affected by wind speed, gusts or turbine operations.

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Improving Wind Turbine Drivetrain Reliability Using a Combined Experimental, Computational, and Analytical Approach

Cited by 5 publications

References 10 publications

A systems engineering analysis of three‐point and four‐point wind turbine drivetrain configurations

A systems engineering analysis of three‐point and four‐point wind turbine drivetrain configurations

Impacts of wind field characteristics and non-steady deterministic wind events on time varying main-bearing loads

Improving wind turbine drivetrain designs to minimize the impacts of non-torque loads

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