Phase control through load control of oscillating-body wave energy converters with hydraulic PTO system

Falcão, António F. de O.

doi:10.1016/j.oceaneng.2007.10.005

Cited by 194 publications

(85 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In reference [80], Falcão applies latching control to a wave energy device with a high-pressure hydraulic PTO system, as previously developed in reference [61]. He notes that the hydraulic PTO system provides a natural method of achieving latching: the body remains stationary for as long as the hydrodynamic forces on its wetted surface are unable to overcome the resisting force (gas pressure difference multiplied by the cross-sectional area of the ram) of the PTO system.…”

Section: Latching Controlmentioning

confidence: 99%

A review of wave energy converter technology

Drew

Plummer

Şahinkaya

2009

Proceedings of the Institution of Mechanical Engineers, Part A:

977

504

View full text Add to dashboard Cite

Ocean waves are a huge, largely untapped energy resource, and the potential for extracting energy from waves is considerable. Research in this area is driven by the need to meet renewable energy targets, but is relatively immature compared to other renewable energy technologies. This review introduces the general status of wave energy and evaluates the device types that represent current wave energy converter (WEC) technology, particularly focusing on work being undertaken within the United Kingdom. The possible power take-off systems are identified, followed by a consideration of some of the control strategies to enhance the efficiency of point absorber-type WECs. There is a lack of convergence on the best method of extracting energy from the waves and, although previous innovation has generally focused on the concept and design of the primary interface, questions arise concerning how best to optimize the powertrain. This article concludes with some suggestions of future developments.

show abstract

Section: Latching Controlmentioning

confidence: 99%

A review of wave energy converter technology

Drew

Plummer

Şahinkaya

2009

Proceedings of the Institution of Mechanical Engineers, Part A:

977

504

View full text Add to dashboard Cite

show abstract

“…In this case, the latching duration (or equivalently, the unlatching time) can be optimized to synchronize the peak of the velocity with the peak of the excitation force [25] or to maximize the absorbed power [9]. In addition, a number of different strategies have been proposed to determine the best unlatching time for polychromatic waves; see, e.g., [26][27][28][29][30][31][32]. In this study, the body is unlatched at the instant when the excitation force passes a chosen threshold (threshold unlatching [30]).…”

Section: Latching Controlmentioning

confidence: 99%

Control-Informed Geometric Optimization of Wave Energy Converters: The Impact of Device Motion and Force Constraints

2015

View full text Add to dashboard Cite

Abstract:The energy cost for producing electricity via wave energy converters (WECs) is still not competitive with other renewable energy sources, especially wind energy. It is well known that energy maximising control plays an important role to improve the performance of WECs, allowing the energy conversion to be performed as economically as possible. The control strategies are usually subsequently employed on a device that was designed and optimized in the absence of control for the prevailing sea conditions in a particular location. If an optimal unconstrained control strategy, such as pseudo-spectral optimal control (PSOC), is adopted, an overall optimized system can be obtained no matter whether the control design is incorporated at the geometry optimization stage or not. Nonetheless, strategies, such as latching control (LC), must be incorporated at the optimization design stage of the WEC geometry if an overall optimized system is to be realised. In this paper, the impact of device motion and force constraints in the design of control-informed optimized WEC geometries is addressed. The aim is to verify to what extent the constraints modify the connection between the control and the optimal device design. Intuitively, one might expect that if the constraints are very tight, the optimal device shape is the same regardless of incorporating or not the constrained control at the geometry optimization stage. However, this paper tests the hypothesis that the imposition of constraints will limit the control influence on the optimal device shape. PSOC, LC and passive control (PC) are considered in this study. In addition, constrained versions of LC and PC are presented.

show abstract

“…To broaden the bandwidth, K. Budal & S. Salter have proposed phase control (see [17,18] for more recent accounts). An alternative answer seems to be provided by several recent designs based on the idea of a compact array of small buoys (figure 6).…”

Section: A Compact Array Of Small Buoysmentioning

confidence: 99%

Hydrodynamic principles of wave power extraction

Mei

2012

Phil. Trans. R. Soc. A.

View full text Add to dashboard Cite

The hydrodynamic principles common to many wave power converters are reviewed via two representative systems. The first involves one or more floating bodies, and the second water oscillating in a fixed enclosure. It is shown that the prevailing basis is impedance matching and resonance, for which the typical analysis can be illustrated for a single buoy and for an oscillating water column. We then examine the mechanics of a more recent design involving a compact array of small buoys that are not resonated. Its theoretical potential is compared with that of a large buoy of equal volume. A simple theory is also given for a two-dimensional array of small buoys in well-separated rows parallel to a coast. The effects of coastline on a land-based oscillating water column are examined analytically. Possible benefits of moderate to large column sizes are explored. Strategies for broadening the frequency bandwidth of high efficiency by controlling the power-takeoff system are discussed.

show abstract

Phase control through load control of oscillating-body wave energy converters with hydraulic PTO system

Cited by 194 publications

References 8 publications

A review of wave energy converter technology

A review of wave energy converter technology

Control-Informed Geometric Optimization of Wave Energy Converters: The Impact of Device Motion and Force Constraints

Hydrodynamic principles of wave power extraction

Contact Info

Product

Resources

About