scholarly journals Experimental and numerical investigations of a two-body floating-point absorber wave energy converter in regular waves

2019 ◽  
Vol 91 ◽  
pp. 102613 ◽  
Author(s):  
Qianlong Xu ◽  
Ye Li ◽  
Yi-Hsiang Yu ◽  
Boyin Ding ◽  
Zhiyu Jiang ◽  
...  
Keyword(s):  
Wave Energy ◽  
Wave Energy Converter ◽  
Floating Point ◽  
Regular Waves ◽  
Energy Converter ◽  
Numerical Investigations ◽  
Point Absorber

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

Motion simulation and performance analysis of two-body floating point absorber wave energy converter

2020 ◽  
Vol 157 ◽  
pp. 353-367
Author(s):  
Yong Ma ◽  
Aiming Zhang ◽  
Lele Yang ◽  
Hao Li ◽  
Zhenfeng Zhai ◽  
...  
Keyword(s):  
Performance Analysis ◽  
Wave Energy ◽  
Wave Energy Converter ◽  
Floating Point ◽  
Motion Simulation ◽  
Energy Converter ◽  
Point Absorber ◽  
And Performance

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 Experimental Wave Tank Test for Reference Model 3 Floating-Point Absorber Wave Energy Converter Project

2015 ◽  
Author(s):  
Y. H. Yu ◽  
M. Lawson ◽  
Y. Li ◽  
M. Previsic ◽  
J. Epler ◽  
...  
Keyword(s):  
Wave Energy ◽  
Reference Model ◽  
Wave Energy Converter ◽  
Floating Point ◽  
Energy Converter ◽  
Wave Tank ◽  
Point Absorber ◽  
Tank Test

scholarly journals Study on a Floating Point Absorber Type Wave Energy Converter with One Line Tension Leg Mooring

2018 ◽  
Vol 27 (0) ◽  
pp. 79-88
Author(s):  
Tomoki Taniguchi ◽  
Shunka C. Hirao ◽  
Kentaroh Kokubun ◽  
Tadashi Nimura ◽  
Shigesuke Ishida ◽  
...  
Keyword(s):  
Wave Energy ◽  
Line Tension ◽  
Wave Energy Converter ◽  
Floating Point ◽  
Energy Converter ◽  
Point Absorber ◽  
Type Wave

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.

scholarly journals Passive Model Predictive Control on a Two-Body Self-Referenced Point Absorber Wave Energy Converter

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1731
Author(s):  
Dan Montoya ◽  
Elisabetta Tedeschi ◽  
Luca Castellini ◽  
Tiago Martins
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Wave Energy ◽  
Power Flow ◽  
Linear Constraints ◽  
Wave Energy Converter ◽  
Control Technique ◽  
Computational Time ◽  
Energy Converter ◽  
Point Absorber

Wave energy is nowadays one of the most promising renewable energy sources; however, wave energy technology has not reached the fully-commercial stage, yet. One key aspect to achieve this goal is to identify an effective control strategy for each selected Wave Energy Converter (WEC), in order to extract the maximum energy from the waves, while respecting the physical constraints of the device. Model Predictive Control (MPC) can inherently satisfy these requirements. Generally, MPC is formulated as a quadratic programming problem with linear constraints (e.g., on position, speed and Power Take-Off (PTO) force). Since, in the most general case, this control technique requires bidirectional power flow between the PTO system and the grid, it has similar characteristics as reactive control. This means that, under some operating conditions, the energy losses may be equivalent, or even larger, than the energy yielded. As many WECs are designed to only allow unidirectional power flow, it is necessary to set nonlinear constraints. This makes the optimization problem significantly more expensive in terms of computational time. This work proposes two MPC control strategies applied to a two-body point absorber that address this issue from two different perspectives: (a) adapting the MPC formulation to passive loading strategy; and (b) adapting linear constraints in the MPC in order to only allow an unidirectional power flow. The results show that the two alternative proposals have similar performance in terms of computational time compared to the regular MPC and obtain considerably more power than the linear passive control, thus proving to be a good option for unidirectional PTO systems.

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