Effect of Control Strategies and Power Take-Off Efficiency on the Power Capture From Sea Waves

Tedeschi, Elisabetta; Carraro, Matteo; Molinas, Marta; Mattavelli, Paolo

doi:10.1109/tec.2011.2164798

Cited by 136 publications

(96 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A PTO system that includes large accumulation systems, such as an overtopping device [38] or any wave-activated device with a hydraulic transmission system that includes large hydraulic accumulators [13,39], provides slowly-varying, smooth torque signals. In contrast, transmission systems directly connected to the electric generator, such as air turbines in oscillating water column devices [40], mechanical systems [14] or hydraulic systems without large accumulators [41] provide highly variable torque signals. Therefore, realistic operational conditions can be categorised in two groups: constant input torque and variable input torque.…”

Section: Experiments Designmentioning

confidence: 99%

“…Such W2W models should include balanced parsimonious models for each stage (including nonlinear dynamics if required and considering the constraints and losses of each component), meaning that the level of detail included in the sub-models for the different stages of the W2W model is balanced. The most important aspects to be considered when modelling W2W models are reviewed in [11] for several different PTO systems (pneumatic [12], hydraulic [13], or a mechanical transmission system [14] coupled to a rotational generator, or a direct drive system with a linear generator [15]), which have been suggested in the literature for different WECs.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Validating a Wave-to-Wire Model for a Wave Energy Converter—Part II: The Electrical System

2017

View full text Add to dashboard Cite

Abstract:The incorporation of the full dynamics of the different conversion stages of wave energy converters (WECs), from ocean waves to the electricity grid, is essential for a realistic evaluation of the power flow in the drive train. WECs with different power take-off (PTO) systems, including diverse transmission mechanisms, have been developed in recent decades. However, all the different PTO systems for electricity-producing WECs, regardless of any intermediate transmission mechanism, include an electric generator, linear or rotational. Therefore, accurately modelling the dynamics of electric generators is crucial for all wave-to-wire (W2W) models. This paper presents the models for three popular rotational electric generators (squirrel cage induction machine, permanent magnet synchronous generator and doubly-fed induction generator) and a back-to-back (B2B) power converter and validates such models against experimental data generated using three real electric machines. The input signals for the validation of the mathematical models are designed so that the whole operation range of the electrical generators is covered, including input signals generated using the W2W model that mimic the behaviour of different hydraulic PTO systems. Results demonstrate the effectiveness of the models in accurately reproducing the characteristics of the three electrical machines, including power losses in the different machines and the B2B converter.

show abstract

Section: Experiments Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Validating a Wave-to-Wire Model for a Wave Energy Converter—Part II: The Electrical System

2017

View full text Add to dashboard Cite

show abstract

“…Classical control methods such as reactive control, (Budal and Falnes, 1977) and latching, (Budal and Falnes, 1980) have been used to extract maximum or close to maximum average power. The effect of system constraints have been investigated, (Fusco and Ringwood, 2013) as well as the use of a realistic non-ideal Power Take Off (PTO), (Tedeschi et al, 2011). Both latching and reactive control were originally designed to operate in monochromatic seas, however, there have been attempts to extend their use for irregular sea conditions, (Fusco and Ringwood, 2011;Babarit et al, 2004).…”

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

View full text Add to dashboard Cite

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.

show abstract

“…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: 91%

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

et al. 2015

View full text Add to dashboard Cite

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.

show abstract

Effect of Control Strategies and Power Take-Off Efficiency on the Power Capture From Sea Waves

Cited by 136 publications

References 16 publications

Validating a Wave-to-Wire Model for a Wave Energy Converter—Part II: The Electrical System

Validating a Wave-to-Wire Model for a Wave Energy Converter—Part II: The Electrical System

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

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

Contact Info

Product

Resources

About