DC link voltage control for direct drive linear wave energy converter

2017 ◽  
Author(s):  
Felipe Yoshimatsu Abe ◽  
Ivan Eduardo Chabu ◽  
Lourenco Matakas
Keyword(s):  
Wave Energy ◽  
Voltage Control ◽  
Wave Energy Converter ◽  
Linear Wave ◽  
Direct Drive ◽  
Energy Converter

Design and test of a novel two-body direct-drive wave energy converter

2020 ◽  
pp. 1-18
Author(s):  
Chuan Liu ◽  
Renwen Chen ◽  
Yuxiang Zhang ◽  
Wen Liu ◽  
Liping Wang ◽  
...  
Keyword(s):  
Permanent Magnet ◽  
Wave Energy ◽  
Fem Simulation ◽  
Wave Theory ◽  
Wave Energy Converter ◽  
Linear Wave ◽  
Direct Drive ◽  
Energy Converter ◽  
Motion Equations ◽  
Linear Generator

As a renewable energy, ocean wave energy is exploited with infinite potential to solve the energy crisis. In this study, we develop a novel two-body direct-drive wave energy converter (DD-WEC) to surmount the problems associated with low power density, low direct-drive speed of the buoys, seawater corrosion and maintenance in the existing two-body WEC. Its prototype consists of two cylindrical buoys are utilized that float horizontally at sea level and the Halbach permanent magnet linear generator (HPMLG) that is employed in the power take-off (PTO) system. The energy is extracted from the relative motion between two buoys oscillating. Compared with the existing WEC, the proposed WEC has more vigorous motion between buoys, higher conversion efficiency and little extra underwater structure, due to the utilization of the horizontal buoys and the HPMLG. First, the motion equations of buoys are derived on the basis of linear wave theory. And depending on the motion equations, the structure of buoys and the HPMLG is designed. And we found that compared with the existing WEC, the proposed WEC has more vigorous motion between buoys in the seawater waves oscillation. Then, based on finite-element method (FEM), the performance of the HPMLG is evaluated, and it can generate 19% more power than the traditional permanent magnet linear generator (TPMLG) based on the same wave motion. Finally, the DD-WEC prototype is manufactured based on the designed parameter. The manufactured prototype is tested in the test platform and the wave tank. The measured output voltage is highly consistent with the observed variation trends in FEM simulation data. The results show that the proposed DD-WEC is well suited for wave energy conversion.

Power Conditioning Unit for Direct-Drive Wave Energy Converter

2018 ◽  
Author(s):  
Yuriy Rozanov ◽  
Konstantin Kryukov ◽  
Mikhail Kiselev ◽  
Mikhail Lepanov ◽  
Yuriy Tserkovsky ◽  
...  
Keyword(s):  
Wave Energy ◽  
Wave Energy Converter ◽  
Direct Drive ◽  
Power Conditioning ◽  
Energy Converter

Numerical Simulation of Duck Wave Energy Converter

2016 ◽  
Vol 693 ◽  
pp. 484-490
Author(s):  
Ying Xue Yao ◽  
Hai Long Li ◽  
Jin Ming Wu ◽  
Liang Zhou
Keyword(s):  
Numerical Simulation ◽  
Wave Energy ◽  
Pitch Angle ◽  
Low Cost ◽  
Three Dimensional ◽  
Angular Frequency ◽  
Wave Energy Converter ◽  
Linear Wave ◽  
Energy Converter ◽  
Flow Theories

Duck wave energy converter has the advantages of high conversion efficiency, simple construction, low cost relative to other wave power device. In the paper, the numerical simulation of the response of the converter was calculated by the AQWA software which based on the three dimensional potential flow theories. The results show that the pitch angle appear the peak when the incident wave frequency is 1rad/s and the maximum of the pitch angle come out as the linear wave normally incident the duck body, which means duck wave energy converter can absorb more wave energy in this angular frequency. The above research can provide reference for the design of the duck wave energy converter.

A Joint Numerical and Experimental Study of a Surging Point Absorbing Wave Energy Converter (WRASPA)

2009 ◽  
Author(s):  
Majid A. Bhinder ◽  
Clive G. Mingham ◽  
Derek M. Causon ◽  
Mohammad T. Rahmati ◽  
George A. Aggidis ◽  
...  
Keyword(s):  
Wave Energy ◽  
Informed Choice ◽  
Wave Energy Converter ◽  
Body Motion ◽  
Numerical Dissipation ◽  
Small Scale ◽  
Linear Wave ◽  
Energy Converter ◽  
Non Linear ◽  
Experimental Project

This paper presents the findings from using several commercial computational fluid dynamics codes in a joint numerical and experimental project to simulate WRASPA, a new wave energy converter (WEC) device. A series of fully 3D non-linear simulations of WRASPA are presented. Three commercial codes STAR-CCM, CFX and FLOW-3D are considered for simulating the WRASPA device and final results are presented based on the use of Flow-3D. Results are validated by comparison to experimental data obtained from small scale tank tests undertaken at Lancaster University (LU). The primary aim of the project is to use numerical simulation to optimize the collector geometry for power production over a range of likely wave climates. A secondary aim is to evaluate the ability of commercial codes to simulate rigid body motion in linear and non-linear wave climates in order to choose the optimal code with respect to compute speed and ease of problem setup. Issues relating to the ability of a code in terms of numerical dissipation of waves, wave absorption, wave breaking, grid generation and moving bodies will all be discussed. The findings of this paper serve as a basis for an informed choice of commercial package for such simulations. However the capability of these commercial codes is increasing with every new release.

scholarly journals Analysis, design and testing of a novel direct‐drive wave energy converter system

2013 ◽  
Vol 7 (5) ◽  
pp. 565-573 ◽  
Author(s):  
Richard Crozier ◽  
Helen Bailey ◽  
Markus Mueller ◽  
Edward Spooner ◽  
Paul McKeever
Keyword(s):  
Wave Energy ◽  
Wave Energy Converter ◽  
Direct Drive ◽  
Energy Converter ◽  
Analysis Design ◽  
Design And Testing

Influence of Generator Damping on Peak Power and Variance of Power for a Direct Drive Wave Energy Converter

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Magnus Stålberg ◽  
Rafael Waters ◽  
Oskar Danielsson ◽  
Mats Leijon
Keyword(s):  
Wave Energy ◽  
Peak Power ◽  
Load Resistance ◽  
Wave Energy Converter ◽  
Damping Factor ◽  
Direct Drive ◽  
Energy Converter ◽  
Swedish West Coast ◽  
Electric System ◽  
Point Absorber

The first offshore prototype of a wave energy converter system has been launched off the Swedish west coast. The concept is based on a point absorber directly coupled to a linear generator located on the ocean floor. The wave energy converter is part of a research project that will study the electric system of ten units forming a small farm of wave power plants as they are linked and connected to an electric grid. A full scale farm will consist of a large number of interconnected units. The chosen direct drive system reduces the mechanical complexity of the converter but has repercussions on the electric system. The output from the generator will vary with the speed of the point absorber, leading to large fluctuations of power on the second scale. This has implications on both the individual generator and on the system as a whole. The hydrodynamic behavior of the point absorber depends, to a large extent, on the damping of the generator. The damping, in turn, can be remotely controlled by changing the load resistance. It has previously been shown that this has a large influence on the power absorbed by the wave energy converter. This paper investigates the peak power, the translator speed, and the variance of the power at different sea states and for different levels of damping. The peak power has an impact on the design of the generator and the required ability, for a single unit, to handle electric overloads. The momentum of the translator is directly proportional to its speed. The speed is thus important for the design of the end stop. The variance of the power of one unit will have an impact on the farm system behavior. The study is based on two and a half months of experimental measurements on the prototype wave energy converter and a wave measurement buoy. The aim is to analyze whether load control strategies may influence the dimensioning criteria for the electric system and the generator. The results are compared to previously investigated relationships between the absorbed mean power and the load resistance as a function of sea state. In the study, it was found that the maximum power is approximately proportional to the average power, while the maximum translator speed and standard deviation decrease as the damping factor is increased.

scholarly journals Performance analysis of a point-absorber wave energy converter with a single buoy composed of three rigidly coupled structures

2021 ◽  
Vol 4 (2) ◽  
pp. 37-45
Author(s):  
Aldo Ruezga ◽  
José M. Cañedo C. ◽  
Manuel G. Verduzco-Zapata ◽  
Francisco J. Ocampo-Torres
Keyword(s):  
Wave Energy ◽  
Wave Energy Converter ◽  
Floating Body ◽  
Analysis Tool ◽  
Direct Drive ◽  
Energy Converter ◽  
Drive Power ◽  
Point Absorber ◽  
Single Body ◽  
Coupled Structures

A single-body point absorber system is analysed to improve its power absorption at a finite water depth.  The proposed wave energy converter consists of a single floating body coupled to a direct-drive power take-off system placed on the seabed. The structure of a cylindrical buoy with large draft is changed by a single body composed of three structures rigidly coupled, reducing its volume and improving its frequency-dependent hydrostatic parameters that are obtained through a numerical analysis tool called NEMOH. The undamped natural frequency of the oscillating system is tuned to a specified wave period and the performance of the WEC system is obtained assuming a linear Power Take-Off system. In time domain, the performance of the WEC device is carried-out under a regular (sinusoidal) and irregular incident wave profile. Comparing the performance of the WEC system using the cylindrical and the proposed buoy outcomes that the system with the proposed buoy is able to absorb more energy from incident waves with a wider frequency range, whereas the oscillating system is kept as simple as possible.

Sign in / Sign up

Export Citation Format

Share Document