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- Book Chapter:
Lynn
This chapter aims to shed light on such alternating current (AC) curiosities as reactance and impedance, real and reactive power and power factor correction to introduce the operating principles of electrical generators and explains how modern electronic control eases the problem of converting unruly marine energy into the well‐behaved electricity required by an electricity grid. Finally, the…
- Conference Paper:
Ringwood
This paper examines the challenges of efficiently harnessing wave energy. A variety of energy conversion device types is reviewed and a generic heaving buoy device selected for detailed examination. A number of modelling and control challenges are detailed and a hierarchical control structure is indicated. Both potable water production and electricity generation are included as possible uses…
- Journal Article:
Müller et al.
Marine energy conversion systems are highlighted among nonconventional renewable energy sources for their availability and energy density. Most marine energy conversion systems are based on multigenerator units or arrays, projected to inject power to the grid in the megawatt range. The current solution for regulating generators and managing power output is the use of two-level voltage-source…
- Journal Article:
Forslund et al.
This paper validates a simulation model that couples an electrical model in Simulink with a hydrodynamic vortex-model by comparing with experimental data. The simulated system is a vertical axis current turbine connected to a permanent magnet synchronous generator in a direct drive configuration. Experiments of load and no load operation were conducted to calibrate the losses of the turbine,…
- Journal Article:
Victor et al.
Overtopping wave energy converters (OWECs) are designed to extract energy from ocean waves based on wave overtopping into a reservoir, which is emptied into the ocean through a set of low-head turbines, and typically feature a low crest freeboard and a smooth impermeable steep slope. In the process of optimizing the performance of OWECs, the question arises whether adapting the slope geometry…
- Conference Paper:
Choi et al.
This paper proposes new control method of maximum power point tracking for the tidal energy generation system using the duty ratio control of buck type DC-DC converter. An advantage of new MPPT(Maximum Power Point Tracking) control method presented in this paper is not necessary to use the tidal turbine characteristic at various tidal speed and measure the tidal speed or/and the rotation speed…
- Journal Article:
Liu et al.
Marine current turbines need to operate at sea for a long time, facing a changeable marine environment and harsh working conditions, and are prone to component failures. Therefore, it is necessary to use efficient and reliable pitch technology to achieve unattended, stable, month-long operation corresponding to lunar rhythm, enhance redundancy and reliability, and extend the service life of…
- Thesis:
Nelson
The marine renewable energy community is interested in maximizing the power generated by nonlinear wave energy converters. Optimal control methods provide a tool to achieve this aim and can also help to inform the buoy design. An energy-optimal control law for a class of non-linear buoy models is derived and is shown to be singular. The solution approach is illustrated using an hourglass-…
- Journal Article:
Farajvand et al.
In guiding the progression, development, and operation of wave energy converters (WECs) in a more efficient way, mathematical analysis and understanding of the dynamic process is essential. Mathematical WEC models, obtained either by numerical analysis or physical modelling, form the basis of most (model-based) energy maximising control strategies available in the literature, where…
- Journal Article:
Trapanese et al.
In this paper, a linear generator for a highly reliable wave energy conversion system is designed and tested. In order to store energy, the system is able to produce hydrogen. The wave energy conversion system consists of an electrical linear generator, a power conversion system, and a sea-water electrolyzer. A small-scale prototype of the system is designed and built. The design is oriented…
- Journal Article:
Mahdy et al.
In this paper, we use a nonlinear model of a grid-connected Archimedes wave swing (AWS) to explore the actual generation potential of this wave energy conversion system. Our model has never been used before for a grid-connected AWS. The control system employs six proportional-integral (PI) controllers to maximize the energy harvest from waves, to minimize the generator power losses, and to…
- Journal Article:
Mahdy et al.
This paper introduces an enhancement to the transient stability of a wave energy conversion system (WECS) by using the coot optimization algorithm (COA) combined with an anti-windup method. This combination helps in elimination of the windup issue in the integral term of the proportional-integral (PI) controller during power system faults leading to a significant enhancement for the transient…
- Journal Article:
Babarit et al.
When hydraulic power take off (PTO) is used to convert the mechanical energy of a wave energy converter (WEC) into a more useful form of energy, the PTO force needs to be controlled. Continuous controlled variation of the PTO force can be approximated by a set of discrete values. This can be implemented using either variable displacement pumps or several hydraulic cylinders or several high…
- Journal Article:
Hillis et al.
CCell is a type of Oscillating Surge Wave Energy Converter (OSWEC) under development by Zyba Renewables Ltd. Laboratory scale wave tank tests have been conducted with a prototype device equipped with a passive controllable hydraulic power take-off system. The results are used to derive a simplified semi-analytical model of the governing hydrodynamics, providing a basis for simulation studies…
- Journal Article:
Ulvin et al.
The goal of this paper is to investigate the power extraction capability for the Wave Energy Converter (WEC) concept BOLT®. Specifically, the impact of different control strategies on the power extraction and their high sensitivity to the incoming waves will be presented. The BOLT® concept is based on a flat point absorber designed with a small mass and a Power Take-Off (PTO) solely…
- Report:
Boström et al.
In this project, the direct-driven linear generator (LG) of the wave energy converter (WEC) designed at Uppsala University (UU) will be investigated. The purpose is to simulate the power output from single and several WECs and connect to a micro grid with the use of a real-time (RT) emulator at University College Cork (UCC), Ireland. The analysis will include considerations on WEC control…
- Report:
Dehlsen Associates LLC
Dehlsen Associates’ Centipod wave energy converter’s (WEC) main potential design limitation is the inherent theoretical capture limit of a single degree of freedom (DoF) heaving point absorber. This TEAMER project aimed to leverage the expertise of Oregon State University WESRF’s personnel to implement a second DoF in the existing model predictive control (MPC) optimization formulation, …
- Report:
CalWave Power Technologies
CalWave seeks to conduct scaled, experimental prototype testing for a total duration of 10 working days at the W2 Basin at University of Maine. Scaled wave tank testing of a representative scaled wave energy converter prototype in a controlled environment will greatly de-risk CalWave’s upcoming deployment of a larger scale prototype off San Diego, California and ensure operation of CalWave’s…
- Book Chapter:
Davidson et al.
Wave energy conversion is an active field of research, aiming to harness the vast amounts of energy present in ocean waves. An essential development trajectory towards an economically competitive wave energy converter (WEC) requires early device experimentation and refinement using numerical tools. OpenFOAM ® is proving to be a useful numerical tool for WEC development, having been…
- Report:
Hunt and Rumker
Ocean current energy represents a vast untapped source of renewable energy that exists on the outer continental shelf areas of the 5 major continents. Ocean currents are unidirectional in nature and are perpetuated by thermal and salinity sea gradients, as well as coriolis forces imparted from the earth's rotation. This report details THORs Power Method, a breakthrough power control method…
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