scholarly journals Wind and Wave Disturbances Compensation to Floating Offshore Wind Turbine Using Improved Individual Pitch Control Based on Fuzzy Control Strategy

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Feng Yang ◽  
Qing-wang Song ◽  
Lei Wang ◽  
Shan Zuo ◽  
Sheng-shan Li

Due to the rich and high quality of offshore wind resources, floating offshore wind turbine (FOWT) arouses the attentions of many researchers. But on a floating platform, the wave and wind induced loads can significantly affect power regulation and vibration of the structure. Therefore, reducing these loads becomes a challenging part of the design of the floating system. To better alleviate these fatigue loads, a control system making compensations to these disturbances is proposed. In this paper an individual pitch control (IPC) system integrated with disturbance accommodating control (DAC) and model prediction control (MPC) through fuzzy control is developed to alleviate the fatigue loads. DAC is mainly used to mitigate the effects of wind disturbance and MPC counteracts the effects of wave on the structure. The new individual pitch controller is tested on the NREL offshore 5 MW wind turbine mounted on a barge with a spread-mooring system, running in FAST, operating above-rated condition. Compared to the original baseline collective pitch control (CPC) (Jonkman et al., 2007), the IPC system shows a better performance in reducing fatigue loads and is robust to complex wind and wave disturbances as well.

Author(s):  
Mohammed Khair Al-Solihat ◽  
Meyer Nahon ◽  
Kamran Behdinan

This paper presents a rigid multibody dynamic model to simulate the dynamic response of a spar floating offshore wind turbine (FOWT). The system consists of a spar floating platform, the moorings, the wind turbine tower, nacelle, and the rotor. The spar platform is modeled as a six degrees-of-freedom (6DOFs) rigid body subject to buoyancy, hydrodynamic and moorings loads. The wind turbine tower supports rigid nacelle and rotor at the tip. The rigid rotor is modeled as a disk spinning around its axis and subject to the aerodynamic load. The generator torque control law is incorporated into the system dynamics to capture the rotor spinning speed response when the turbine is operating below the rated wind speed. The equations of motions are derived using Lagrange's equation in terms of the platform quasi-coordinates and rotor spin speed. The external loads due to hydrostatics, hydrodynamics, and aerodynamics are formulated and incorporated into the equations of motion. The dynamic simulations of the spar FOWT are performed for three load cases to examine the system eigen frequencies, free decay response, and response to a combined wave and wind load. The results obtained from the present model are validated against their counterparts obtained from other simulation tools, namely, FAST, HAWC2, and Bladed, with excellent agreement. Finally, the influence of the rotor gyroscopic moment on the system dynamics is investigated.


2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Zhixin Zhao ◽  
Wenhua Wang ◽  
Dongdong Han ◽  
Wei Shi ◽  
Yulin Si ◽  
...  

Abstract A braceless semi-submersible floating platform is proposed for a Technical University of Denmark (DTU) 10-MW wind turbine at moderate water depths with reference to an existing National Renewable Energy Laboratory (NREL) 5-MW braceless semi-submersible floating platform, and a servo control system for a 10-MW semi-submersible floating offshore wind turbine (FOWT) is introduced. To control the ultimate and fatigue loads of the FOWT, a fore-aft tuned mass damper (TMD) installed in the nacelle of the 10-MW semi-submersible FOWT was investigated for vibration alleviation and load reduction. Considering the hydrodynamic and mooring effect, a four degrees-of-freedom (DOFs) (platform surge and pitch motions, tower fore-aft bending, and TMD translation) simplified dynamic model for the 10-MW semi-submersible FOWT is established based on D’Alembert’s principle. Then, the parameter estimation is conducted based on the Levenberg–Marquardt (LM) algorithm, and the simplified dynamic model was further verified by comparing the output responses with FAST and the proposed model. Furthermore, the exhaustive search (ES) and genetic algorithm (GA) are embedded into the simplified dynamic model to optimize the TMD parameters. Finally, a fully coupled time-domain simulation for all the selected environmental conditions is conducted in FAST, and the vibration suppression performance of the optimized TMD design for the 10-W semi-submersible FOWT was further examined and analyzed.


Author(s):  
Iman Ramzanpoor ◽  
Martin Nuernberg ◽  
Longbin Tao

Abstract The main drivers for the continued decarbonisation of the global energy market are renewable energy sources. Moreover, the leading technological solutions to achieve this are offshore wind turbines. As installed capacity has been increasing rapidly and shallow water near shore sites are exhausted, projects will need to be developed further from shore and often in deeper waters, which will pose greater technical challenges and constrain efforts to reduce costs. Current floating platform solutions such as the spar and semi-submersible rely on large amounts of ballast and complex structural designs with active stabilisation systems for stability of the floating offshore wind turbine platform (FOWT). The primary focus of this study is to present a design concept and mooring arrangement for an alternative floating platform solution that places emphasis on the mooring system to achieve stability for a FOWT. The tension leg buoy (TLB) is designed to support future 10MW offshore wind turbine generators. This paper presents the numerical methodology used for a coupled hydro-elastic analysis of the floater and mooring system under combined wind, wave and current effects. A concept TLB design is presented and its platform motion and mooring line tension characteristics are analysed for a three-hour time domain simulation representing operating and survival conditions in the northern North Sea with water depths of 110 metres. The importance of wave drift forces and the other non-linear excitation forces in the concept design stage are evaluated by comparing the motion and tension responses of three different numerical simulation cases with increasing numerical complexity. The preliminary TLB system design demonstrated satisfactory motion response for the operation of a FOWT and survival in a 100-year storm condition. The results show that accounting for second-order effect is vital in terms of having a clear understanding of the full behaviour of the system and the detailed response characteristics in operational and survival conditions. Extreme loads are significantly reduced when accounting for the second-order effects. This can be a key aspect to not overdesign the system and consequently achieve significant cost savings.


Author(s):  
Federico Taruffi ◽  
Simone Di Carlo ◽  
Sara Muggiasca ◽  
Alessandro Fontanella

Abstract This paper deals with the numerical design of a floating offshore wind turbine outdoor large-scale prototype based on the DTU 10MW. The objective of this work is to develop a numerical simulation environment for the design of an outdoor scaled prototype. The numerical model is realized coupling the preliminary designed Blue Growth Farm large-scale turbine model with a traditional floater, the OC3 spar buoy. The numerical model is used to evaluate the loads associated with the wind turbine when combined to a floating foundation, with the focus on the coupling between the dynamics of the control system and the one of the floating platform. In addition to this, also the consistency of loads on crucial turbine components is an interesting test bench for the evaluation of the dynamical effects and drives the final design of the physical model.


Author(s):  
Kaman Thapa Magar ◽  
Mark J. Balas

This paper presents the preliminary study on damping of platform pitch motion of floating offshore wind turbine using adaptive individual blade pitch control. The platform pitch displacement is measured and used to derive the signal to actuate pitch of each blade independently which tries to damp the platform pitch motion. This independent blade pitch control signal is then combined with collective blade pitch control signal which is responsible for regulating the generator speed. The performance of proposed controller is compared with the baseline PID collective pitch controller and adaptive collective pitch controller.


2021 ◽  
Vol 172 ◽  
pp. 453-464
Author(s):  
Le Quang Sang ◽  
Qing’an Li ◽  
Chang Cai ◽  
Takao Maeda ◽  
Yasunari Kamada ◽  
...  

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