Wave Prediction and Robust Control of Heaving Wave Energy Devices for Irregular Waves

Schoen, Marco P.; Hals, Jørgen; Moan, Torgeir

doi:10.1109/tec.2010.2101075

Cited by 83 publications

(53 citation statements)

References 16 publications

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“…Other advanced control methods have been investigated; such as fuzzy logic, (Schoen et al, 2011), bang-bang control, (Abraham and Kerrigan, 2013), pseudo spectral control, (Paparella and Ringwood, 2016) and model predictive control (MPC), . In this paper MPC is utilised as the control algorithm due to its ability to produce optimal results, whilst easily incorporating system constraints within the optimisation, (Maciejowski, 2002).…”

Section: Introductionmentioning

confidence: 99%

The Effect of Viscosity on the Maximisation of Electrical Power from a Wave Energy Converter under Predictive Control

O'Sullivan

Lightbody

2017

IFAC-PapersOnLine

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In this paper, the non-linear effects of viscosity on the performance of a Wave Energy Converter (WEC) system are analysed. A standard linear Model Predictive Control (MPC) is used to show the negative effects that the unaccounted non-linear viscosity force in the hydrodynamic system has on the power absorption. A non-linear MPC (NLMPC) is then implemented, where the non-linear viscosity effects are included in the optimisation. A linear drag coefficient estimate of the non-linear viscosity is then included in the linear MPC; creating a Linear Viscous Model Predictive Control. When constraints are incorporated, it is shown that a single choice of the linear viscous drag coefficient for use within the linear MPC can provide comparable results to the non-linear MPC approach, over a wide range of sea states.

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Section: Introductionmentioning

confidence: 99%

The Effect of Viscosity on the Maximisation of Electrical Power from a Wave Energy Converter under Predictive Control

O'Sullivan

Lightbody

2017

IFAC-PapersOnLine

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“…On the other hand a Model Predictive Controller (MPC) has the ability to use the sea state prediction in order to maximize the power during the prediction horizon. Requirements for sea state prediction is widely discussed in Schoen et al (2011). In Fusco and Ringwood (2012) and Fusco and Ringwood (2010), different prediction algorithms for short term wave forecasting are presented.…”

Section: Introductionmentioning

confidence: 99%

Model Predictive Control of Buoy Type Wave Energy Converter

Soltani

Sichani

Mirzaei

2014

IFAC Proceedings Volumes

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The paper introduces the Wavestar wave energy converter and presents the implementation of model predictive controller that maximizes the power generation. The ocean wave power is extracted using a hydraulic electric generator which is connected to an oscillating buoy. The power generator is an additive device attached to the buoy which may include damping, stiffness or similar terms hence will affect the dynamic motion of the buoy. Therefore such a device can be seen as a closed-loop controller. The objective of the wave energy converter is to harvest as much energy from sea as possible. The straight forward solution to this maximization problem is achieved by maximizing the instantaneous range of motion of the buoy. The buoy as a single degree of freedom oscillator will undergo its maximum movements when it is in resonance with the sea state. Hence the best solution to the problem is achieved by forcing this condition. In the paper the theoretical framework for this principal is shown. The optimal controller requires information of the sea state for infinite horizon which is not applicable. Model Predictive Controllers (MPC) can have finite horizon which crosses out this requirement. This approach is then taken into account and an MPC controller is designed for a model wave energy converter and implemented on a numerical example. Further, the power outtake of this controller is compared to the optimal controller as an indicator of the performance of the designed controller.

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“…8 Some algorithms are being implemented on a theoretical level at present. 9 In order to avoid expensive and vulnerable control system and breaking mechanisms, another strategy would be to use a passive system to engineer the frequency response of the point absorber so as to be in resonance with the dominant sea states at the chosen location. In addition, it is also important to keep the power capture ratio at low levels in extreme sea states, to reduce the maximum loads on the system.…”

Section: Introductionmentioning

confidence: 99%

A resonant two body system for a point absorbing wave energy converter with direct-driven linear generator

Engström

Kurupath

Isberg

et al. 2011

Journal of Applied Physics

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Wave power calculations for a wave energy conversion device connected to a drogue Journal of Renewable and Sustainable Energy 6, 013117 (2014) Based on an earlier conceptual model of a two body system point absorbing wave energy converter tuned to resonance in Swedish west coast sea states, an extended coupled hydrodynamic, mechanic, and electromagnetic model has been developed. The hydrodynamic characteristics of the two body system are studied in the frequency and time domain, while its response to real Swedish west coast sea states are studied in the time domain, by using a wave energy converter model with two independently moving bodies connected to a direct driven linear generator with non-linear damping. The two body system wave energy converter gives nearly 80% power capture ratio in irregular waves. The resonant behaviour is shown to be sensitive to the shape of the spectrum, and the distance between the two bodies is shown to have a large effect on the power absorption.

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Wave Prediction and Robust Control of Heaving Wave Energy Devices for Irregular Waves

Cited by 83 publications

References 16 publications

The Effect of Viscosity on the Maximisation of Electrical Power from a Wave Energy Converter under Predictive Control

The Effect of Viscosity on the Maximisation of Electrical Power from a Wave Energy Converter under Predictive Control

Model Predictive Control of Buoy Type Wave Energy Converter

A resonant two body system for a point absorbing wave energy converter with direct-driven linear generator

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