A real time sliding mode control for a wave energy converter based on a wells turbine

Barambones, Óscar; Cortajarena, José Antonio; Durana, José Marı́a González de; Alkorta, Patxi

doi:10.1016/j.oceaneng.2018.05.058

Cited by 19 publications

(15 citation statements)

References 33 publications

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“…In this case, a comparison between the proposed control criterion and two previous reported comparable criteria [5,11] is displayed. For a clear visualisation of the comparison results, a wave profile composed of two consecutive trains of perturbed monochromatic waves has been used.…”

Section: Case Study 2: Regular Wavesmentioning

confidence: 99%

“…Wells turbine) [4]. Subsequently, the mechanical to electrical energy conversion is performed through a variable speed generator, for instance a double fed induction generator (DFIG), which has largely proven its suitability for variable speed operation in energy conversion applications [5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

“…In [10] and, more recently, in [7,11], researchers have obtained very good results to increase wave energy extraction by regulating the rotational speed, computing the reference speed to avoid turbine stall. Another interesting approach has been introduced in [5,12], where energy extraction enhancement is successfully achieved by operating at the flow coefficient of maximum turbine efficiency, which results in variable rotational speed operation. Then, the novel criterion developed in this paper naturally arises as a continuation of the aforementioned contributions, focusing on maximising the wave energy extraction, by considering the mechanical system as a whole.…”

Section: Introductionmentioning

confidence: 99%

“…In fact, since its origin [13][14][15], SMC has evolved into a powerful technique to design robust controllers for a broad range of nonlinear applications [16][17][18][19][20]. In particular, [5,11] recently proposed first-order SMC schemes for OWC systems, accomplishing highly satisfactory results. Motivated by their encouraging outcomes with first-order SMC, in this paper a second-order sliding mode (SOSM) control setup is developed.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Optimal wave energy extraction for oscillating water columns using second‐order sliding mode control

Mosquera

Evangelista

Puleston

et al. 2020

IET Renewable Power Generation

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Ocean waves are an important renewable energy resource and several fields of R&D are concurrently working to improve technologies for harnessing their power. In that context, this study presents a control to optimise the performance of oscillating water column systems. As a first contribution, a novel criterion to attain maximum wave energy extraction is developed, resulting in an enhancement of the global power efficiency of the system. Then, taking advantage of the proposed criterion, a second-order sliding mode control setup is designed, with power extraction maximisation the primary objective and reactive power regulation a secondary one. Simulation results confirm the highly satisfactory performance of the proposed controller and its robustness in the presence of the inherent uncertainties and disturbances in the non-linear system.

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Section: Case Study 2: Regular Wavesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Optimal wave energy extraction for oscillating water columns using second‐order sliding mode control

Mosquera

Evangelista

Puleston

et al. 2020

IET Renewable Power Generation

View full text Add to dashboard Cite

show abstract

“…The uncertainty demeanor of the waves is dependent on the weather, which implies that OWC performance can change everyday; this results in a power variance that can affect the generator output [12]. Furthermore, a main disadvantage of Wells turbines is the stalling phenomenon that happens at low rotational speeds [13,14]. Both detriments can be compensated through the use of a control strategy that regulates the rotor speed.…”

Section: Introductionmentioning

confidence: 99%

Double Fed Induction Generator Control Design Based on a Fuzzy Logic Controller for an Oscillating Water Column System

et al. 2021

Self Cite

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Oscillating water column (OWC) systems are water power generation plants that transform wave kinetic energy into electrical energy by a surrounded air column in a chamber that changes its pressure through the waves motion. The chamber pressure output spins a Wells turbine that is linked to a doubly fed induction generator (DFIG), flexible devices that adjust the turbine speed to increase the efficiency. However, there are different nonlinearities associated with these systems such as weather conditions, uncertainties, and turbine stalling phenomenon. In this research, a fuzzy logic controller (FLC) combined with an airflow reference generator (ARG) was designed and validated in a simulation environment to display the efficiency enhancement of an OWC system by the regulation of the turbine speed. Results show that the proposed framework not only increased the system output power, but the stalling is also avoided under different pressure profiles.

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Nonlinear control with wave observer to maximize harvested power for point absorber wave energy converters

Duc

2020

Asian Journal of Control

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This paper designs control laws that maximize the harvested power for submerged point absorber wave energy converters (PAWECs) constrained to heave motion. First, a mathematical model of a submerged PAWEC driven by nonlinear hydrodynamic, friction, restoring, and harvested power forces is derived. Second, a new disturbance observer is designed that globally practically exponentially estimate the wave velocity and its time derivatives.Next, the optimal operating points are derived such that when the PAWEC operates at these points, the harvested power is maximized. Fourth, nonlinear control laws are designed to track the optimal operating points based on the proposed disturbance observer and Lyapunov's direct method. In addition to maximize the harvested power, these optimal control laws ensure that the harvested power is always nonnegative; i.e., no power is drawn from the network to the PAWEC at any time. For comparison, a control law that maximizes the hydrodynamic extraction power is also designed. Several simulations are carried out and illustrate that the maximizing harvested power control yields better results than others. K E Y W O R D Sdisturbance observer, maximizing harvested power, nonlinear control, wave energy converter | INTRODUCTIONDue to shortage of fossil fuels and environmental concerns, non-combustible renewable energy (including wind, solar, waves, and others) conversion technologies have attracted attention from governments, academy, and industries. Ocean waves offer higher energy density (2-3 kW/m 2 ) than other renewable resources (wind 0.4-0.6 kW/m 2 , solar 0.1-0.2 kW/m 2 ) [1,2], little energy loss under large travel distance [3], larger predictable capability than both wind and solar energy [1], good correlation between source and demand (natural seasonal variability of wave energy follows the electricity demand in temperature climate), [3] limited negative

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A real time sliding mode control for a wave energy converter based on a wells turbine

Cited by 19 publications

References 33 publications

Optimal wave energy extraction for oscillating water columns using second‐order sliding mode control

Optimal wave energy extraction for oscillating water columns using second‐order sliding mode control

Double Fed Induction Generator Control Design Based on a Fuzzy Logic Controller for an Oscillating Water Column System

Nonlinear control with wave observer to maximize harvested power for point absorber wave energy converters

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