Feedforward control for wave disturbance rejection on floating offshore wind turbines

Al, Mees; Fontanella, Alessandro; Hoek, Daan van der; Liu, Yichao; Belloli, Marco; Wingerden, Jan‐Willem van

doi:10.1088/1742-6596/1618/2/022048

Cited by 12 publications

(8 citation statements)

References 4 publications

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“…For an improved controller performance, multivariable controllers can be applied, which feed back not only one signal but, next to the rotor speed, tower-top or platform motion signals for improved damping [24,25,26,27,28,29,23]. These controllers are often state feedback controllers, which require measurements of all states of the controller design model.…”

Section: Controlsmentioning

confidence: 99%

Advances on Reduced-Order Modeling of Floating Offshore Wind Turbines

Lemmer

Steinacker

et al. 2021

Volume 9: Ocean Renewable Energy

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Aero-hydro-servo-elastic modeling of Floating Offshore Wind Turbines (FOWTs) is a key component in the design process of various components of the system. Different approaches to order reduction have been investigated with the aim of improving structural design, manufacturing, transport and installation, but also the dynamic behavior, which is largely affected by the blade pitch controller. The present work builds on previous works on the SLOW (Simplified Low-Order Wind Turbine) code, which has already been used for the above purposes, including controller design. While the previous rigid rotor model gives good controllers in most cases, we investigate in the present work the question if aero-elastic effects in the design model can improve advanced controllers. The SLOW model is extended for the flap-wise bending and coupled to NREL’s AeroDyn, linearized and verified with the OlavOlsen OO-Star Wind Floater Semi 10MW public FOWT model. The results show that the nonlinear and linear reduced-order SLOW models agree well against OpenFAST. The state-feedback Linear Quadratic Regulator (LQR) applied with the same weight functions to both models, the old actuator disk, and the new aero-elastic model shows that the LQR becomes more sensitive to nonlinear excitation and that the state feedback matrix is significantly different, which has an effect on the performance and potentially also on the robustness. Thus modeling uncertainties might even be more critical for the LQR of the higher-fidelity model.

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Section: Controlsmentioning

confidence: 99%

Advances on Reduced-Order Modeling of Floating Offshore Wind Turbines

Lemmer

Steinacker

et al. 2021

Volume 9: Ocean Renewable Energy

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show abstract

“…This section defines the floating system that is considered in this study. The FOWT is formed by the DTU 10 MW (Bak et al, 2013) wind turbine and the INNWIND.EU TripleSpar platform (Azcona et al, 2017;Lemmer et al, 2020a). The characteristics of this FOWT concept are similar to those of current commercial projects and are publicly available.…”

Section: Definition Of a Reference Floating Wind Turbinementioning

confidence: 99%

Model-based design of a wave-feedforward control strategy in floating wind turbines

Fontanella

Al²,

Wingerden

et al. 2021

Wind Energ. Sci.

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Abstract. Floating wind turbines rely on feedback-only control strategies to mitigate the negative effects of wave excitation. Improved power generation and lower fatigue loads can be achieved by including information about incoming waves in the turbine controller. In this paper, a wave-feedforward control strategy is developed and implemented in a 10 MW floating wind turbine. A linear model of the floating wind turbine is established and utilized to understand how wave excitation affects rotor speed and so power, as well as to show that collective pitch is suitable for reducing the effects of wave excitation. A feedforward controller is designed based on the inversion of the linear model, and a gain-scheduling algorithm is proposed to adapt the feedforward action as wind speed changes. The performance of the novel wave-feedforward controller is examined first by means of linear analysis and then with non-linear time-domain simulations in FAST. This paper proves that including some information about incoming waves in the turbine controller can play a crucial role in improving power quality and the turbine fatigue life. In particular, the proposed wave-feedforward control strategy achieves this goal complementing the industry-standard feedback pitch controller. Together with the wave-feedforward control strategy, this paper provides some insights about the response of floating wind turbines to collective-pitch control and waves, which could be useful in future control-design studies.

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“…In the present case, the parametric model is defined by means of system identification of the impulse response function of the force coefficients Jonkman et al (2018); Lemmer (ne Sandner), whereas frequency-domain data (i.e. the force coefficients) are used for identification in Al et al (2020). The wave-force model of panel code data is non-causal, which means a force is developed before the wave reaches the center of the platform.…”

Section: Frequency-dependent Hydrodynamic Loadsmentioning

confidence: 99%

“…Based on the predicted wave forces, a finite-horizon LQR controller is designed and applied to a TLP-FOWT to minimize the tower-base fore-aft bending moment, achieving mixed results. In Al et al (2020) an inversion-based feedforward control strategy is introduced, showing it is an effective way of reducing wave-induced rotor speed oscillations.…”

Section: Introductionmentioning

confidence: 99%

Model-based design of a wave-feedforward control strategy in ﬂoating wind turbines

Fontanella¹,

Al²,

Wingerden³

et al. 2021

Preprint

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Abstract. Floating wind turbines rely on feedback-only control strategies to mitigate the effects of wave excitation. Improved power generation and lower fatigue loads can be achieved by including information about the incoming waves into the wind turbine controller. In this paper, a wave-feedforward control strategy is developed and implemented in a 10 MW floating wind turbine. A linear model of the floating wind turbine is established and utilized to show how wave excitation affects the wind turbine rotor speed output, and that collective-pitch is an effective control input to reject the wave disturbance. Based on the inversion of the same model, a feedforward controller is designed, and its performance is examined by means of linear analysis. A gain-scheduling algorithm is proposed to adapt the feedforward action as the wind speed changes. Non-linear time-domain simulations prove that the proposed feedforward control strategy is an effective way of reducing rotor speed oscillations and structural fatigue loads caused by waves.

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Feedforward control for wave disturbance rejection on floating offshore wind turbines

Cited by 12 publications

References 4 publications

Advances on Reduced-Order Modeling of Floating Offshore Wind Turbines

Advances on Reduced-Order Modeling of Floating Offshore Wind Turbines

Model-based design of a wave-feedforward control strategy in floating wind turbines

Model-based design of a wave-feedforward control strategy in ﬂoating wind turbines

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