Performance Analysis on the Use of Oscillating Water Column in Barge-Based Floating Offshore Wind Turbines

Undesired motions in Floating Offshore Wind Turbines (FOWT) lead to reduction of system efficiency, the system’s lifespan, wind and wave energy mitigation and increment of stress on the system and maintenance costs. In this article, a new barge platform structure for a FOWT has been proposed with the objective of reducing these undesired platform motions. The newly proposed barge structure aims to reduce the tower displacements and platform’s oscillations, particularly in rotational movements. This is achieved by installing Oscillating Water Columns (OWC) within the barge to oppose the oscillatory motion of the waves. Response Amplitude Operator (RAO) is used to predict the motions of the system exposed to different wave frequencies. From the RAOs analysis, the system’s performance has been evaluated for representative regular wave periods. Simulations using numerical tools show the positive impact of the added OWCs on the system’s stability. The results prove that the proposed platform presents better performance by decreasing the oscillations for the given range of wave frequencies, compared to the traditional barge platform.

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Switching Control Strategy for Oscillating Water Columns Based on Response Amplitude Operators for Floating Offshore Wind Turbines Stabilization

Applied Sciences ◽

10.3390/app11115249 ◽

2021 ◽

Vol 11 (11) ◽

pp. 5249

Author(s):

Payam Aboutalebi ◽

Fares M’zoughi ◽

Itziar Martija ◽

Izaskun Garrido ◽

Aitor J. Garrido

Keyword(s):

Switching Control ◽

Response Amplitude ◽

Offshore Wind ◽

Oscillating Water Column ◽

Offshore Wind Turbines ◽

Floating Offshore Wind Turbines ◽

Water Columns ◽

Switching Control Strategy ◽

Response Amplitude Operators ◽

Oscillating Water Columns

In this article, a new strategy for switching control has been proposed with the aim of reducing oscillations in floating offshore wind turbines. Such oscillations lead to a shortage in the system’s efficiency, lifespan and harvesting capability of wind and wave energies. In order to study the decreasing of undesired oscillations in the system, particularly in pitch and top tower fore-aft movements, a square-shaped platform barge equipped with four symmetric oscillating water columns has been considered. The oscillating water columns’ air flux valves allow to operate the air columns so that to control the barge movements caused by oscillatory motion of the waves. In order to design the control scheme, response amplitude operators have been used to evaluate the performance of the system for a range of wave frequency profiles. These response amplitude operators analysis makes it possible to implement a switching control strategy to adequately regulate the valves opening/closing transition. The obtained results show that the proposed controlled oscillating water column-based barge present a better performance compared to the traditional barge one. In the case study with the period of 10 s, the results indicate the significant oscillation reduction for the controlled oscillating water column-based system compared to the standard barge system by 30.8% in pitch angle and 25% in fore-aft displacement.

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Complementary Airflow Control of Oscillating Water Columns for Floating Offshore Wind Turbine Stabilization

Mathematics ◽

10.3390/math9121364 ◽

2021 ◽

Vol 9 (12) ◽

pp. 1364

Author(s):

Fares M’zoughi ◽

Payam Aboutalebi ◽

Izaskun Garrido ◽

Aitor J. Garrido ◽

Manuel De La Sen

Keyword(s):

Control Strategy ◽

Structural Response ◽

Offshore Wind ◽

Offshore Wind Turbine ◽

Offshore Wind Turbines ◽

Floating Offshore Wind Turbines ◽

Water Columns ◽

The Comparative Study ◽

Oscillating Water Columns ◽

And Control

The implementation and integration of new methods and control techniques to floating offshore wind turbines (FOWTs) have the potential to significantly improve its structural response. This paper discusses the idea of integrating oscillating water columns (OWCs) into the barge platform of the FOWT to transform it into a multi-purpose platform for harnessing both wind and wave energies. Moreover, the OWCs will be operated in order to help stabilize the FOWT platform by means of an airflow control strategy used to reduce the platform pitch and tower top fore-aft displacement. This objective is achieved by a proposed complementary airflow control strategy to control the valves within the OWCs. The comparative study between a standard FOWT and the proposed OWC-based FOWT shows an improvement in the platform’s stability.

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Pitch Angle Control of Floating Offshore Wind Turbines by H∞ Control

IEEJ Transactions on Electronics Information and Systems ◽

10.1541/ieejeiss.134.1096 ◽

2014 ◽

Vol 134 (8) ◽

pp. 1096-1103 ◽

Cited By ~ 8

Author(s):

Sho Tsujimoto ◽

Ségolène Dessort ◽

Naoyuki Hara ◽

Keiji Konishi

Keyword(s):

Wind Turbines ◽

Pitch Angle ◽

Offshore Wind ◽

Offshore Wind Turbines ◽

Floating Offshore Wind Turbines

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Blade Pitch Angle Control for Floating Offshore Wind Turbines by Model Predictive Control

IEEJ Transactions on Electronics Information and Systems ◽

10.1541/ieejeiss.135.882 ◽

2015 ◽

Vol 135 (7) ◽

pp. 882-892 ◽

Cited By ~ 4

Author(s):

Segolene Dessort ◽

Sho Tsujimoto ◽

Naoyuki Hara ◽

Keiji Konishi

Keyword(s):

Model Predictive Control ◽

Predictive Control ◽

Wind Turbines ◽

Pitch Angle ◽

Offshore Wind ◽

Offshore Wind Turbines ◽

Floating Offshore Wind Turbines ◽

Blade Pitch Angle

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Impact of Typhoons on Floating Offshore Wind Turbines: A Case Study of Typhoon Mangkhut

Journal of Marine Science and Engineering ◽

10.3390/jmse9050543 ◽

2021 ◽

Vol 9 (5) ◽

pp. 543

Author(s):

Jiawen Li ◽

Jingyu Bian ◽

Yuxiang Ma ◽

Yichen Jiang

Keyword(s):

Wind Turbine ◽

Wind Turbines ◽

Safety Evaluation ◽

Offshore Wind ◽

Offshore Wind Turbine ◽

Motion Response ◽

Offshore Wind Turbines ◽

Floating Offshore Wind Turbines ◽

Coupling Motion

A typhoon is a restrictive factor in the development of floating wind power in China. However, the influences of multistage typhoon wind and waves on offshore wind turbines have not yet been studied. Based on Typhoon Mangkhut, in this study, the characteristics of the motion response and structural loads of an offshore wind turbine are investigated during the travel process. For this purpose, a framework is established and verified for investigating the typhoon-induced effects of offshore wind turbines, including a multistage typhoon wave field and a coupled dynamic model of offshore wind turbines. On this basis, the motion response and structural loads of different stages are calculated and analyzed systematically. The results show that the maximum response does not exactly correspond to the maximum wave or wind stage. Considering only the maximum wave height or wind speed may underestimate the motion response during the traveling process of the typhoon, which has problems in guiding the anti-typhoon design of offshore wind turbines. In addition, the coupling motion between the floating foundation and turbine should be considered in the safety evaluation of the floating offshore wind turbine under typhoon conditions.

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Effects of Second-Order Hydrodynamic Forces on Floating Offshore Wind Turbines

32nd ASME Wind Energy Symposium ◽

10.2514/6.2014-0361 ◽

2014 ◽

Cited By ~ 7

Author(s):

Tiago M. Duarte ◽

António J. Sarmento ◽

Jason M. Jonkman

Keyword(s):

Wind Turbines ◽

Hydrodynamic Forces ◽

Second Order ◽

Offshore Wind ◽

Offshore Wind Turbines ◽

Floating Offshore Wind Turbines

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Open-Loop Control Co-Design of Floating Offshore Wind Turbines Using Linear Parameter-Varying Models

10.1115/detc2021-67573 ◽

2021 ◽

Author(s):

Athul K. Sundarrajan ◽

Yong Hoon Lee ◽

James T. Allison ◽

Daniel R. Herber

Keyword(s):

Wind Turbines ◽

Open Loop ◽

Offshore Wind ◽

Linear Parameter ◽

Design Decisions ◽

Linear Parameter Varying ◽

Offshore Wind Turbines ◽

Floating Offshore Wind Turbines ◽

Parameter Varying ◽

And Control

Abstract This paper discusses a framework to design elements of the plant and control systems for floating offshore wind turbines (FOWTs) in an integrated manner using linear parameter-varying models. Multiple linearized models derived from high-fidelity software are used to model the system in different operating regions characterized by the incoming wind speed. The combined model is then used to generate open-loop optimal control trajectories as part of a nested control co-design strategy that explores the system’s stability and power production in the context of crucial plant and control design decisions. A cost model is developed for the FOWT system, and the effect of plant decisions and subsequent power and stability response of the FOWT is quantified in terms of the levelized cost of energy (LCOE) for that system. The results show that the stability constraints and the plant design decisions affect the turbine’s power and, subsequently, LCOE of the system. The results indicate that a lighter plant in terms of mass can produce the same power for a lower LCOE while still satisfying the constraints.

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Software-in-the-Loop Combined Machine Learning for Dynamic Responses Analysis of Floating Offshore Wind Turbines

10.1115/omae2021-65524 ◽

2021 ◽

Author(s):

Peng Chen ◽

Changhong Hu ◽

Zhiqiang Hu

Keyword(s):

Machine Learning ◽

Experimental Data ◽

Wind Turbines ◽

Dynamic Responses ◽

Offshore Wind ◽

Learning Technology ◽

Mean Values ◽

Offshore Wind Turbines ◽

Floating Offshore Wind Turbines ◽

Brute Force Method

Abstract Artificial intelligence (AI) brings a new solution to overcome the challenges of Floating offshore wind turbines (FOWTs) to better predict the dynamic responses with intelligent strategies. A new AI-based software-in-the-loop method, named SADA is introduced in this paper for the prediction of dynamic responses of FOWTs, which is proposed based on an in-house programme DARwind. DARwind is a coupled aero-hydro-servo-elastic in-house program for FOWTs, and a reinforcement learning method with exhaust algorithm and deep deterministic policy gradient (DDPG) are embedded in DARwind as an AI module. Firstly, the methodology is introduced with the selection of Key Disciplinary Parameters (KDPs). Secondly, Brute-force Method and DDPG algorithms are adopted to changes the KDPs’ values according to the feedback of 6DOF motions of Hywind Spar-type platform through comparing the DARwind simulation results and those of basin experimental data. Therefore, many other dynamic responses that cannot be measured in basin experiment can be predicted in good accuracy with SADA method. Finally, the case study of SADA method was conducted and the results demonstrated that the mean values of the platform’s motions can be predicted with higher accuracy. This proposed SADA method takes advantage of numerical-experimental method, basin experimental data and the machine learning technology, which brings a new and promising solution for overcoming the handicap impeding direct use of conventional basin experimental way to analyze FOWT’s dynamic responses during the design phase.

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