Qualitative yaw stability analysis of free-yawing downwind turbines

Wanke, Gesine; Hansen, Morten Hartvig; Larsen, Torben J.

doi:10.5194/wes-4-233-2019

Cited by 7 publications

(6 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Such yaw systems could be cost-efficient as they simplify the turbine control, and reduce operation and maintenance costs, as they could purely be used for cable unwinding. However, Wanke et al (2019c) showed on an example of a 2.1MW turbine with a tilted rotor that such systems align passively at high yaw angles for high wind speeds resulting into significant power loss. The study concluded that tilt angle, cone angle and blade stiffness would need to be specifically designed for a free yawing downwind configuration.…”

mentioning

confidence: 99%

Re-design of an upwind rotor for a downwind configuration: design changes and cost evaluation

Wanke¹,

Bergami²,

Zahle³

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

Abstract. Within this work, an existing model of a Suzlon S111 2.1 MW turbine is used to estimate potential cost savings when the conventional upwind rotor concept is changed into a downwind rotor concept. A design framework is used to get realistic design updates for the upwind conﬁguration as well as two design updates for the downwind conﬁguration, including a pure material cost-out on the rotor blades and a new planform design. A full design load basis according to the standard has been used to evaluate the impact of the redesigns on the loads. A detailed cost model with load scaling is used to estimate the impact of the design changes on the turbine costs and the cost of energy. It is shown that generally lower blade mass can be achieved with the downwind conﬁgurations of up to 5 % less than the upwind redesign. Compared to an upwind baseline, the upwind redesign shows an estimated cost of energy reduction of 2.3 % where the downwind designs achieve a maximum reduction of 1.3 %.

show abstract

mentioning

confidence: 99%

Re-design of an upwind rotor for a downwind configuration: design changes and cost evaluation

Wanke¹,

Bergami²,

Zahle³

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…At 16 m s −1 the drift of the platform stabilises around 39 º. At this yaw position, the destabilising yaw moments generated by the rotor are compensated by restoring yaw moments that appear with the yaw rotation, such as the one due to the weathervanning effect and the restoring moment that is generated at the rotor under yawed inflow wind, as reported by Wanke et al (2019).…”

Section: Blade-level Analysis Of the Causes Of Yaw Momentmentioning

confidence: 64%

“…This type of turbines offer the advantage of having a passive yaw alignment capacity that does not require heavy yaw mechanisms. Wanke et al (2019) explain that, when there is some 2 https://doi.org/10.5194/wes-2022-86 Preprint. Discussion started: 11 October 2022 c Author(s) 2022.…”

Section: Introductionmentioning

confidence: 99%

Platform yaw drift in upwind floating wind turbines with single-point-mooring system and its mitigation by individual pitch control

Sandua-Fernández

Vittori²,

Martín-San-Román³

et al. 2022

Preprint

View full text Add to dashboard Cite

Abstract. This work demonstrates the feasibility of an individual pitch control strategy based on nacelle yaw misalignment measurements to mitigate the platform yaw drift in upwind floating offshore wind turbines, which is caused by the vertical moment produced by the rotor. This moment acts on the platform yaw degree of freedom, being of great importance in systems that have low yaw stiffness. Among them, single-point-mooring platforms are one of the most important ones. During the last years, several floating wind turbine concepts with single-point-mooring systems have been proposed, which can theoretically dispense with yaw mechanism, due to their ability to weather-vane. However, in this paper it is proven that the vertical moment overcomes the orienting ability, causing the yaw drift. With the intention of reducing the induced yaw response of a single-point-mooring floating wind turbine, an individual pitch control strategy based on nacelle yaw misalignment is applied, which introduces a counteracting moment. The control strategy is validated by numerical simulations using the NREL 5 MW wind turbine mounted on a single-point-mooring version of the DeepCwind OC4 floating platform, to demonstrate that it can mitigate the yaw drift and therefore maintain the wind turbine rotor aligned with the wind.

show abstract

“…Because of the natural weather vane properties of downwind rotors, another potential benefit that is not captured in traditional LCOE studies is the opportunity to downsize the yaw actuator or motors 31 . Several works in literature have investigated the topic of free‐yaw downwind rotors, both numerically 32,33 and experimentally with scaled wind tunnel models 34,35 . The experimental studies generally returned promising results, whereas the numerical studies found conditions where the free‐yaw rotor generated large yaw misalignments and power losses.…”

Section: Passive Rotor Yawingmentioning

confidence: 99%

Challenges, opportunities, and a research roadmap for downwind wind turbines

et al. 2021

View full text Add to dashboard Cite

This study investigates the challenges and opportunities presented by downwind wind turbines and offers a roadmap of future research pathways to maximize their potential. Multidisciplinary design, analysis, and optimization comparison studies between upwind and downwind configurations on a modern 10‐MW offshore wind turbine are presented to support the discussion. On one hand, the downwind rotor is found to consistently have a smaller swept area under loading. As a result, the downwind design produces less annual energy production (−1.2%). On the other hand, lighter blades for the downwind configuration lead to lower capital costs (−1.7%), so there is little difference in the levelized cost of energy between the two. Key ultimate and fatigue loads are compared, with some values increasing in the downwind configuration, while others decrease. The impact of a downwind configuration on the tower and the impacts of cone and tilt angles and free‐yaw system on the levelized cost of energy are also investigated. The results show a mix of some advantages and disadvantages. Given these results, four areas of research in advanced controls, highly tilted rotors, higher fidelity aerodynamic models, and floating wind are proposed for downwind wind turbines.

show abstract

Qualitative yaw stability analysis of free-yawing downwind turbines

Cited by 7 publications

References 11 publications

Re-design of an upwind rotor for a downwind configuration: design changes and cost evaluation

Re-design of an upwind rotor for a downwind configuration: design changes and cost evaluation

Platform yaw drift in upwind floating wind turbines with single-point-mooring system and its mitigation by individual pitch control

Challenges, opportunities, and a research roadmap for downwind wind turbines

Contact Info

Product

Resources

About