Model predictive control of a multi-degree-of-freedom wave energy converter with model mismatch and prediction errors

Hillis, Andrew; Yardley, James T.; Plummer, Andrew; Brask, Annette

doi:10.1016/j.oceaneng.2020.107724

Cited by 15 publications

(7 citation statements)

References 14 publications

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“…These WEC research used different power electronics converters according to their applications. In [23], [46], [57]- [66], [47], [67]- [70], [48]- [50], [52]- [54], [56] a three-phase AC/DC/AC converter is used to dispatch power to the grid, and in [23], an active DC/AC converter is used as the control element. In [60], a single-phase AC/DC/AC converter is used.…”

Section: Power Conversion Technologymentioning

confidence: 99%

A Review of Power Electronics for Nearshore Wave Energy Converter Applications

et al. 2022

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In compliance with the green energy policy, mitigation from high fossil fuel dependency is becoming a new objective for most countries, including Malaysia. Wave energy is among extensively explored renewable energy relatively clean, sustainable, and inexhaustible resources. To this day, neither definite wave energy technology nor widely available commercial wave farm supplying the grid has existed. Therefore, wave energy harvesting is the most compelling solution, especially in regions where the possibility of grid connection is low in the nearest future. Like other renewable energy, the voltage amplitude and frequency generated from waves are unstable and may vary continuously. This uncertainty has created energy transfer challenges since the grid requires a stable and uninterrupted energy supply. Therefore, power electronics devices are employed to modulate the controller circuits' pulse width. Further understanding of the relationship between wave energy conversion technology and its power conversion, particularly for nearshore applications, is summarized. This work also discussed selected wave energy conversion research and power conversion system implemented and studied in Malaysia. Finally, this review can provide extensive overview and broad understanding into power conversion system for Wave Energy Conversion, especially for nearshore applications.

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Section: Power Conversion Technologymentioning

confidence: 99%

A Review of Power Electronics for Nearshore Wave Energy Converter Applications

et al. 2022

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“…Most multi-variable control strategies require a linearised statespace model of the system for their formulation. The WEC under consideration here has previously been described in [10],…”

Section: Linearised Dynamic System Modelmentioning

confidence: 99%

“…The subscripts R and F refer to the reactor and float, respectively. Due to large float motions in operation, K PTO is not constant [10]. This is also true for the mooring system, but the reactor motion is much smaller than the float motion.…”

Section: The Wavesub Wecmentioning

confidence: 99%

“…The system matrices are given in Equation (10), where M ∞ ∈ ℝ 6×6 is the sum of the body mass matrix and its infinite added mass matrix (obtained from the BEM solution), B v ∈ ℝ 6×6 is a linear viscous damping matrix empirically tuned to experimental data [14], and {K M , K PTO } ∈ ℝ 6×6 are the linearised stiffness matrices for the mooring and PTO lines, respectively (see [15]). These include pretension and spring stiffness terms and take the form…”

Section: Linearised Dynamic System Modelmentioning

confidence: 99%

“…Most multi‐variable control strategies require a linearised state‐space model of the system for their formulation. The WEC under consideration here has previously been described in [10], where the reactor was assumed to be fixed by a taut mooring system. Here we are interested in exploring the effect of the control system on the reactor and mooring lines so the state‐space model must be extended to include these elements.…”

Section: The Wavesub Wecmentioning

confidence: 99%

See 2 more Smart Citations

Wave energy converter platform stabilisation and mooring load reduction through power take‐off control

Hillis

Courtney

Brask

2021

IET Renewable Power Gen

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Mooring systems are a significant capital cost of a floating wave energy converter and their premature failure negatively impacts operational costs. Excessive peak loads and accumulated fatigue damage can lead to failure, so these factors are cost drivers in wave energy converter design. Here, the potential to reduce platform motion and mooring loads through modification of the power take-off (PTO) control are investigated. An approximate velocity tracking control strategy is implemented with a linear quadratic regulator design method using differential weighting of system states. It is demonstrated that the controller can be tuned to capture similar mean power to an optimally tuned, passively damped system while significantly reducing mooring line cyclic loading. The relative accumulated fatigue damage in the mooring lines in a high energy sea-state is found to be reduced by between 43% and 92% as a result of using the approximate velocity tracking control strategy.

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