Experimental and Numerical Study on Point Absorber Type Wave Energy Converter With Linear Generator

2017 ◽  
Author(s):  
Tomoki Taniguchi ◽  
Jun Umeda ◽  
Toshifumi Fujiwara ◽  
Hiroki Goto ◽  
Shunji Inoue
Keyword(s):  
Wave Energy ◽  
Power Output ◽  
Wave Energy Converter ◽  
Complex Conjugate ◽  
Vertical Force ◽  
Regular Waves ◽  
Energy Converter ◽  
Linear Generator ◽  
Point Absorber ◽  
Type Wave

This paper addresses experimental and numerical validation of power output efficiency about an approximate complex-conjugate control with considering the copper loss (ACL) method. A bottom-fixed point absorber type wave energy convertor (WEC) model was used for the experiments carried out at National Maritime Research Institute, Japan (NMRI). In order to model a power take-off (PTO) system constructed by a permanent magnet linear generator (PMLG), a liner shaft motor (LSM) was used for the model test. To investigate characteristics of the ACL method, the resistive load control (RLC) method and approximate complex-conjugate control (ACC) method were also tested by the WEC model. A simulation code based on WEC-Sim (Wave Energy Converter SIMulator) v2.0 written by MATLAB/Simulink, which is developed by collaboration works between the National Renewable Energy Laboratory (NREL) and Sandia National Laboratories (Sandia), was used for the validation. The simulated results in regular waves have good agreement with measured ones in terms of the float heave motion, the vertical force and the control input force. Through the experiments and numerical simulations in regular waves, the ACL method has advantages in high power production compared with the RLC and the ACC methods for the WEC model. In addition, the power output characteristics of the ACL method in irregular waves were checked experimentally and numerically.

Numerical Simulation and Optimization of a Wave Energy Converter for the Izu Islands Sea in Japan

2014 ◽  
Author(s):  
Takeshi Kamio ◽  
Makoto Iida ◽  
Chuichi Arakawa
Keyword(s):  
Numerical Simulation ◽  
Wave Energy ◽  
Power Output ◽  
Test Site ◽  
Wave Energy Converter ◽  
Complex Conjugate ◽  
Maximum Output ◽  
Energy Converter ◽  
Simulation And Optimization ◽  
Izu Islands

The purpose of this study is the numerical simulation and control optimization of a wave energy converter to estimate the power at a test site in the Izu Islands. In Japan, ocean energy is once again being seriously considered; however, since there are many inherent problems due to severe conditions such as the strong swells and large waves, estimations are important when designing such devices. The numerical simulation method in this study combines the wave interaction analysis software WAMIT and an in-house time-domain simulation code using the Newmark-β method, and introduces approximate complex-conjugate control into the code. The optimized parameters were assessed for a regular sine wave and an irregular wave with a typical wave spectrum. With the optimized parameters, average and maximum output power were estimated for the observed wave data at the test site. The results show a more than 100 kW average power output and a several times larger maximum power output.

scholarly journals The power-capture of a nearshore, modular, flap-type wave energy converter in regular waves

2017 ◽  
Vol 137 ◽  
pp. 394-403 ◽  
Author(s):  
L. Wilkinson ◽  
T.J.T. Whittaker ◽  
P.R. Thies ◽  
S. Day ◽  
D. Ingram
Keyword(s):  
Wave Energy ◽  
Wave Energy Converter ◽  
Regular Waves ◽  
Energy Converter ◽  
Type Wave ◽  
Power Capture

scholarly journals CFD Simulations of Floating Point Absorber Wave Energy Converter Arrays Subjected to Regular Waves

Energies ◽  
2018 ◽  
Vol 11 (3) ◽  
pp. 641 ◽  
Author(s):  
Brecht Devolder ◽  
Vasiliki Stratigaki ◽  
Peter Troch ◽  
Pieter Rauwoens
Keyword(s):  
Wave Energy ◽  
Wave Energy Converter ◽  
Floating Point ◽  
Regular Waves ◽  
Energy Converter ◽  
Cfd Simulations ◽  
Point Absorber

A point absorber wave energy converter with nonlinear hardening spring power-take-off systems in regular waves

2020 ◽  
Vol 234 (4) ◽  
pp. 820-829
Author(s):  
Zhongqiang Zheng ◽  
Zhipeng Yao ◽  
Zongyu Chang ◽  
Tao Yao ◽  
Bo Liu
Keyword(s):  
Nonlinear Wave ◽  
Conversion Efficiency ◽  
Wave Energy ◽  
Wave Energy Converter ◽  
Linear Wave ◽  
Regular Waves ◽  
Energy Converter ◽  
Point Absorber ◽  
Frequency State ◽  
Nonlinear Hardening

Point absorber wave energy converter is one of the most effective wave energy harness devices. Most of the wave energy converters generate energy by oscillating the floating body. Usually, the power-take-off system is simplified as a linear spring and a linear damper. However, the narrow frequency bandwidth around a particular resonant frequency is not suitable for real vibrations applications. Thus, a nonlinear hardening spring and a linear damper are applied in the power-take-off system. The bandwidth of hardening mechanism is discussed. The dynamic model of wave energy converter is built in regular waves with time domain method. The results show that the nonlinear wave energy converter has higher conversion efficiency than the linear wave energy converter more than the natural frequency state. The conversion efficiency of the nonlinear wave energy converter in the low frequency state is closed to the linear converter. The amplitude of the incident wave, the damping of the nonlinear wave energy converter and the nonlinear parameter [Formula: see text] affect the energy capture performance of the wave energy converter.

scholarly journals Power Performance of the Combined Monopile Wind Turbine and Floating Buoy with Heave-type Wave Energy Converter

2019 ◽  
Vol 26 (3) ◽  
pp. 107-114
Author(s):  
Esmaeil Homayoun ◽  
Hassan Ghassemi ◽  
Hamidreza Ghafari
Keyword(s):  
Wind Turbine ◽  
Wave Energy ◽  
Wave Energy Converter ◽  
Dynamic Responses ◽  
Sea Waves ◽  
Power Performance ◽  
Regular Waves ◽  
Energy Converter ◽  
Damping Force ◽  
Type Wave

Abstract This study deals with a new concept of near-shore combined renewable energy system which integrates a monopile wind turbine and a floating buoy with heave-type wave energy converter( WEC). Wave energy is absorbed by power-take-off (PTO) systems. Four different shapes of buoy model are selected for this study. Power performance in regular waves is calculated by using boundary element method in ANSYS-AQWA software in both time and frequency domains. This software is based on three-dimensional radiation/diffraction theory and Morison’s equation using mixture of panels and Morison elements for determining hydrodynamic loads. For validation of the approach the numerical results of the main dynamic responses of WEC in regular wave are compared with the available experimental data. The effects of the heaving buoy geometry on the main dynamic responses such as added mass, damping coefficient, heave motion, PTO damping force and mean power of various model shapes of WEC in regular waves with different periods, are compared and discussed. Comparison of the results showed that using WECs with a curvature inward in the bottom would absorb more energy from sea waves.

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