Tunable Control Strategy for Wave Energy Converters With Limited Power Takeoff Rating

Tedeschi, Elisabetta; Molinas, Marta

doi:10.1109/tie.2011.2181131

Cited by 59 publications

(34 citation statements)

References 28 publications

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“…In this case, in contrast to the passively loaded system, the torque is not in phase with the generator speed. From linear control analysis, it is demonstrated that when a reactive component is added to the applied force, negative power-flow will occur [9]. This can also be understood from the plot of generator speed and force, as seen in Figure 19, where there is a phase difference between these two values.…”

Section: Simulation Results For a Reactive Controlled Systemmentioning

confidence: 82%

“…The second term is a convolution integral, where the convolution kernel, k, can be considered the radiation force impulse response. As discussed by Hals [8], a good approximation is to replace this convolution term by the state-space equivalent represented by Equations (8) and (9).…”

Section: Radiation Forcementioning

confidence: 99%

“…To further investigate this potential, full wave-to-wire simulations will be performed, where the physical limitations and efficiency of the all-electric PTO system are also included. When the control is being referred to as complex conjugate, it is meant that the load parameters are being tuned according to complex conjugate control equations [9] in the non-saturated mode of operation.…”

Section: Wave-to-wire Modelingmentioning

confidence: 99%

“…Instead, Lifesaver is optimized towards maximizing the PTO utilization, which leads to a control method based on damping, where the production force is proportional to the absorber speed. In this control mode, the production force are in phase with the production speed and are referred to as active forces, as opposed to a complex-conjugate control that requires reactive forces, which reduce the PTO utilization [9]. The damping control selected at Lifesaver also avoids the need of real-time wave information and allows for a simple and robust time-invariant control.…”

Section: Introductionmentioning

confidence: 99%

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Exploring the Potential for Increased Production from the Wave Energy Converter Lifesaver by Reactive Control

et al. 2013

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Fred Olsen is currently testing their latest wave energy converter (WEC), Lifesaver, outside of Falmouth Bay in England, preparing it for commercial operation at the Wavehub test site. Previous studies, mostly focusing on hydrodynamics and peak to average power reduction, have shown that this device has potential for increased power extraction using reactive control. This article extends those analyses, adding a detailed model of the all-electric power take-off (PTO) system, consisting of a permanent magnet synchronous generator, inverter and DC-link. Time domain simulations are performed to evaluate the PTO capabilities of the modeled WEC. However, when tuned towards reactive control, the generator losses become large, giving a very low overall system efficiency. Optimal control with respect to electrical output power is found to occur with low added mass, and when compared to pure passive loading, a 1% increase in annual energy production is estimated. The main factor reducing the effect of reactive control is found to be the minimum load-force constraint of the device. These results suggest that the Lifesaver has limited potential for increased production by reactive control. This analysis is nevertheless valuable, as it demonstrates how a wave-to-wire model can be used for investigation of PTO potential, annual energy production estimations and evaluations of different control techniques for a given WEC device.

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Section: Simulation Results For a Reactive Controlled Systemmentioning

confidence: 82%

Section: Radiation Forcementioning

confidence: 99%

Section: Wave-to-wire Modelingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Exploring the Potential for Increased Production from the Wave Energy Converter Lifesaver by Reactive Control

et al. 2013

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“…Additionally the power electronics of the PTO system have to be overrated to withstand high power peaks. This issue is well discussed in [11] and [12].…”

Section: Control Strategiesmentioning

confidence: 93%

Control strategies for combining local energy storage with wells turbine oscillating water column devices

et al. 2015

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This paper proposes three generator control strategies for Wells turbine-based floating oscillating water column (OWC) devices comprising electrical or mechanical energy storage systems. The first control strategy is indicated for low inertia turbine OWC devices that include ultracapacitors. This control law optimizes the power take-off efficiency by means of an instantaneous speed controller that allows variation of the turbine rotational speed in a wave-by-wave basis. In addition, the profile of the electrical power injected into the grid is smoothed, so that a high penetration of wave energy does not threaten the grid stability. The second and third control laws are developed for OWC systems comprising a flywheel. Quasi-constant and variable speed controllers are proposed. These control laws do not maximize the system efficiency but allow the use of simpler, smaller and cheaper power electronics.Additionally the power quality is also optimized. The development of the proposed control algorithms is accomplished by means of simulations and verified with an experimental test rig.

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Control of Wave Energy Converters

Suchithra

Samad

2021

Ocean Engineering &Amp; Oceanography

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Tunable Control Strategy for Wave Energy Converters With Limited Power Takeoff Rating

Cited by 59 publications

References 28 publications

Exploring the Potential for Increased Production from the Wave Energy Converter Lifesaver by Reactive Control

Exploring the Potential for Increased Production from the Wave Energy Converter Lifesaver by Reactive Control

Control strategies for combining local energy storage with wells turbine oscillating water column devices

Control of Wave Energy Converters

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