The influence of power-take-off control on the dynamic response and power output of combined semi-submersible floating wind turbine and point-absorber wave energy converters

An overview of the most important development stages of floating point absorber wave energy converters is presented. At a given location, the wave energy resource has to be first assessed for varying seasons. The mechanisms used to convert wave energy to usable energy vary for different wave energy conversion systems. The power output of the generator will have variations due to varying incident waves. The wave structure-interaction leads to modifications in the incident waves; thus, the power output is also affected. The device has to be stable enough to prevent itself from capsizing. The point absorber will give optimum performance when the incident wave frequencies correspond to the natural frequency of the device. The methods for calculating natural frequencies for pitching and heaving systems are presented. Mooring systems maintain the point absorber at the desired location. Various mooring configurations as well as the most commonly used materials for mooring lines are discussed. An overview of scaled modelling is also presented.

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Coupled dynamic analysis of hybrid offshore wind turbine and wave energy converter

Journal of Offshore Mechanics and Arctic Engineering ◽

10.1115/1.4052936 ◽

2021 ◽

pp. 1-40

Author(s):

Rony JS ◽

Debabrata Karmakar

Keyword(s):

Dynamic Analysis ◽

Wind Turbine ◽

Wave Energy ◽

Wave Energy Converter ◽

Offshore Wind ◽

Irregular Waves ◽

Energy Converter ◽

Point Absorber ◽

Wave Energy Converters ◽

Energy Converters

Abstract The combined offshore wind and wave energy on an integrated platform is an economical solution for the offshore energy industry as they share the infrastructure and ocean space. The study presents the dynamic analysis of the Submerged Tension-Leg Platform (STLP) combined with a heaving-type point absorber wave energy converter (WEC). The feasibility study of the hybrid concept is performed using the aero-servo-hydro-elastic simulation tool FAST. The study analyses the responses of the combined system to understand the influence of the WECs on the STLP platform for various operating conditions of the wind turbine under regular and irregular waves. A positive synergy is observed between the platform and the WECs, and the study also focuses on the forces and moments developed at the interface of the tower and platform to understand the effect of wind energy on the turbine tower and importance of motion amplitudes on the performance of the combined platform system. The mean and standard deviation for the translation and rotational motions of combined wind and wave energy converters are determined for different sea states under both regular and irregular waves to analyse the change in responses of the structure. The study observed a reduction in motion amplitudes of the hybrid floating system with the addition of the wave energy converters around the STLP floater to improve the energy efficiency of the hybrid system. The study helps in understanding the best possible arrangement of point absorber type wave energy converters at the conceptual stage of the design process.

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Experimental and numerical comparisons of self-reacting point absorber wave energy converters in regular waves

Ocean Engineering ◽

10.1016/j.oceaneng.2015.05.027 ◽

2015 ◽

Vol 104 ◽

pp. 370-386 ◽

Cited By ~ 45

Author(s):

Scott J. Beatty ◽

Matthew Hall ◽

Bradley J. Buckham ◽

Peter Wild ◽

Bryce Bocking

Keyword(s):

Wave Energy ◽

Regular Waves ◽

Numerical Comparisons ◽

Point Absorber ◽

Wave Energy Converters ◽

Energy Converters

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Performance assessments of the fully submerged sphere and cylinder point absorber wave energy converters

Modern Physics Letters B ◽

10.1142/s0217984919501689 ◽

2019 ◽

Vol 33 (13) ◽

pp. 1950168 ◽

Cited By ~ 2

Author(s):

Qianlong Xu ◽

Ye Li ◽

Yingkai Xia ◽

Weixing Chen ◽

Feng Gao

Keyword(s):

Wave Height ◽

Wave Energy ◽

Interaction Analysis ◽

Wave Power ◽

Viscous Damping ◽

Power Performance ◽

Point Absorber ◽

Wave Energy Converters ◽

Submerged Sphere ◽

Energy Converters

Fully submerged sphere and cylinder point absorber (PA), wave energy converters (WECs) are analyzed numerically based on linearized potential flow theory. A boundary element method (BEM) (a radiation–diffraction panel program for wave-body interactions) is used for the basic wave-structure interaction analysis. In the present numerical model, the viscous damping is modeled by an equivalent linearized damping which extracts the same amount of wave energy over one cycle as the conventional quadratic damping term. The wave power capture width in each case is predicted. Comparisons are also made between the sphere and cylinder PAs which have identical geometrical scales and submerged depths. The results show that: (i) viscous damping has a greater influence on wave power performance of the cylinder PA than that of the sphere PA; (ii) the increasing wave height reduces wave power performance of PAs; (iii) the cylinder PA has a better wave power performance compared to the sphere PA in larger wave height scenarios, which indicates that fully submerged cylinder PA is a preferable prototype of WEC.

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