Energy-maximising experimental control synthesis via impedance-matching for a multi degree-of-freedom wave energy converter

Faedo, Nicolás; Pasta, Edoardo; Carapellese, Fabio; Orlando, Vincenzo; Pizzirusso, Domenica; Basile, Dario; Sirigu, Sergej Antonello

doi:10.1016/j.ifacol.2022.10.453

Cited by 14 publications

(11 citation statements)

References 7 publications

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“…With the identified response (15), we proceed to synthesise an energy-maximising controller, following the impedancematching theory presented in Section II. In particular, the structure of the feedback controller adopted in this paper, which is used to interpolate the optimal impedance-matching response as in (3), is:…”

Section: Fig Lti Representation Of the Pendulum Controlled Systemmentioning

confidence: 99%

“…Finally, Gubesch et al [14] analyse the experimental response of an oscillating water column system in fixed conditions, moored by a taut and a catenary mooring system, reporting a significant reduction on device performance. Nonetheless, apart from the analysis in [15] (which considers the experimental characterisation of a moored device for control purposes), control design/synthesis for WECs is always performed without including the influence of the mooring systems, even though these can have a strong influence on power production and overall dynamics, as discussed within this section.…”

Section: Introductionmentioning

confidence: 99%

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Data-Based Control Synthesis and Performance Assessment for Moored Wave Energy Conversion Systems: The PeWEC Case

Paduano

Carapellese

Pasta

et al. 2024

IEEE Trans. Sustain. Energy

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With a model-based control strategy, the effectiveness of the associated control action depends on the availability of a representative control-oriented model. In the case of floating offshore wave energy converters (WECs), the device response depends upon the interaction between mooring system, any mechanical parts, and the hydrodynamics of the floating body. This study proposes an approach to synthesise WEC controllers under the effect of mooring forces building a representative data-based linear model able to include any relevant dynamics. Moreover, the procedure is tested on the moored pendulum wave energy converter (PeWEC) by means of a high-fidelity mooring solver, OrcaFlex (OF). In particular, the control action is computed with and without knowledge of the mooring influence, in order to analyse and elucidate the effect of the station-keeping system on the harvested energy. The performance assessment of the device is achieved by evaluating device power on the resource scatter characterising Pantelleria, Italy. The results show the relevance of the mooring dynamics on the device response and final set of control parameters and, hence, a significant influence of the station-keeping system on control synthesis and extracted mechanical power.

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Section: Fig Lti Representation Of the Pendulum Controlled Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Data-Based Control Synthesis and Performance Assessment for Moored Wave Energy Conversion Systems: The PeWEC Case

Paduano

Carapellese

Pasta

et al. 2024

IEEE Trans. Sustain. Energy

Self Cite

View full text Add to dashboard Cite

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“…A set of tests during the experimental campaign has been performed with the aim of identifying the frequency response G ε . By imposing a known, sufficiently exciting, signal ( i.e., a chirp signal in the ISWEC tests, see [38]) as the PTO torque, it is possible to evaluate the empirical transfer function estimate under investigation. Clearly, given the MIMO nature of the controlled system, the tests need to be performed for each controlled DoF, to identify each element of the frequency response G ε , i.e.…”

Section: B Wave To Gyromentioning

confidence: 99%

“…The achieved experimental frequency response can be visualized by applying singular value decomposition to G ε , in the so-called sigma plot [38] (see Fig. 16).…”

Section: B Wave To Gyromentioning

confidence: 99%

Experimental and Numerical Investigation on the Performance of a Moored Pitching Wave Energy Conversion System

Paduano,

Carapellese,

Pasta

et al. 2024

IEEE J. Oceanic Eng.

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This study delves into the question of whether the mooring system influences the dynamics of the device by conducting a comprehensive analysis of the inertial sea wave energy converter (ISWEC). Recognizing that wave energy converters exhibit complex behaviors that often push numerical models beyond their range of validity, this study highlights the importance of developing a representative model that accurately captures the intricate dynamics involved. To address this challenge, an experimental investigation of the ISWEC is conducted, aiming to establish a benchmark model that serves as a reference for validating and refining numerical models. Following the experimental investigation, this study proceeds with a numerical investigation to further explore the influence of the mooring system on the pitching device. The response of the device is analyzed both with and without the mooring system, allowing for a direct comparison of its effects on device dynamics and the associated harvested energy. By conducting numerical simulations under various operating conditions, this study provides an insight into the definition of representative mathematical modeling, analyzing and motivating the strong influence of the mooring system on the performances of a moored pitching wave energy conversion system.

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“…At times the PTO will do work on the buoy, momentarily sacrificing energy extraction to produce a buoy response leading to greater energy extraction later. Energy optimal control has been studied extensively for assumed buoy geometries, including quantifying upper bounds [1,6,7], impedance matching [7][8][9][10][11], and both closed-form [12] and numerical optimal control solutions [13] such as with model predictive control [14][15][16]. Early efforts focused on buoy response regimes that can be modeled using linear differential equations considering a buoy's nonlinear response a more recent focus [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Effect of the Dynamic Froude–Krylov Force on Energy Extraction from a Point Absorber Wave Energy Converter with an Hourglass-Shaped Buoy

et al. 2023

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Point absorber wave energy converter (WEC) control strategies often require accurate models for maximum energy extraction. While linear models are suitable for small motions, the focus is on the nonlinear model of an hour-glass shaped buoy undergoing large vertical displacements. Closed-form expressions for the static and dynamic Froude–Krylov forces are developed. It is shown that, in general, the dynamic and static forces are of similar magnitude, which is not the case for a spherical buoy. While the dynamic force reduces the amplitude of the net buoy force, its shape predicts a larger buoy response than if neglected, causing the nonlinear terms to have an even more significant effect. An input-state feedback linearizing controller is developed to show how the nonlinear model can be used in a control law. A 2.5 m buoy example is simulated to illustrate the approach of tracking an arbitrary displacement reference. For the case considered, the extracted power is 30% larger when the nonlinear dynamic FK force is used in the control law. The hourglass buoy is also compared to a spherical buoy to illustrate differences in their response to regular waves and energy extraction when using the same control laws. A spherical buoy diameter of 7.5 m was required to obtain the same power output as a 5 m tall hourglass buoy. A power-force-amplitude (PFA) metric is introduced to compare energy extraction performance and power take-off requirements. The hourglass buoy’s PFA was 13% larger than the spherical buoy implying that it can produce similar power but with less control effort.

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Energy-maximising experimental control synthesis via impedance-matching for a multi degree-of-freedom wave energy converter

Cited by 14 publications

References 7 publications

Data-Based Control Synthesis and Performance Assessment for Moored Wave Energy Conversion Systems: The PeWEC Case

Data-Based Control Synthesis and Performance Assessment for Moored Wave Energy Conversion Systems: The PeWEC Case

Experimental and Numerical Investigation on the Performance of a Moored Pitching Wave Energy Conversion System

Effect of the Dynamic Froude–Krylov Force on Energy Extraction from a Point Absorber Wave Energy Converter with an Hourglass-Shaped Buoy

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