scholarly journals An Estimation of Hydraulic Power Take-off Unit Parameters for Wave Energy Converter Device Using Non-Evolutionary NLPQL and Evolutionary GA Approaches

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 79
Author(s):  
Mohd Afifi Jusoh ◽  
Mohd Zamri Ibrahim ◽  
Muhamad Zalani Daud ◽  
Zulkifli Mohd Yusop ◽  
Aliashim Albani
Keyword(s):  
Wave Energy ◽  
Human Error ◽  
Estimation Method ◽  
Hydraulic Cylinder ◽  
Hydraulic Motor ◽  
Hydraulic Power ◽  
Matlab Simulink ◽  
Irregular Wave ◽  
Wave Energy Converters ◽  
Hydraulic Accumulator

This study is concerned with the application of two major kinds of optimisation algorithms on the hydraulic power take-off (HPTO) model for the wave energy converters (WECs). In general, the HPTO unit’s performance depends on the configuration of its parameters such as hydraulic cylinder size, hydraulic accumulator capacity and pre-charge pressure and hydraulic motor displacement. Conventionally, the optimal parameters of the HPTO unit need to be manually estimated by repeating setting the parameters’ values during the simulation process. However, such an estimation method can easily be exposed to human error and would subsequently result in an inaccurate selection of HPTO parameters for WECs. Therefore, an effective approach of using the non-evolutionary Non-Linear Programming by Quadratic Lagrangian (NLPQL) and evolutionary Genetic Algorithm (GA) algorithms for determining the optimal HPTO parameters was explored in the present study. A simulation–optimisation of the HPTO model was performed in the MATLAB/Simulink environment. A complete WECs model was built using Simscape Fluids toolbox in MATLAB/Simulink. The actual specifications of hydraulic components from the manufacturer were used during the simulation study. The simulation results showed that the performance of optimal HPTO units optimised by NLPQL and GA approaches have significantly improved up to 96% and 97%, respectively, in regular wave conditions. The results also showed that both optimal HPTO units were capable of generating electricity up to 62% and 77%, respectively, of their rated capacity in irregular wave circumstances.

Innovative Hydraulic Power Take-Off Construction and Performance Tests for Wave Energy Conversion

2013 ◽  
Vol 432 ◽  
pp. 316-323 ◽  
Author(s):  
J.C. Antolín-Urbaneja ◽  
J. Lasa ◽  
P. Estensoro ◽  
I. Cabanes ◽  
M. Marcos
Keyword(s):  
Energy Conversion ◽  
Wave Energy ◽  
Initial Conditions ◽  
Low Frequency ◽  
Control Valve ◽  
Hydraulic Cylinder ◽  
Geometrical Parameters ◽  
Wave Energy Conversion ◽  
Hydraulic Motor ◽  
Hydraulic Power

This document describes and demonstrates the features of a new innovative hydraulic Power take-Off (PTO) to be used for Wave Energy Conversion. This device is able to transform low frequency oscillating movement into a continuous high frequency angular speed, absorbing high fluctuated torque at the input shaft, which can reach up to 8000Nm. Moreover, the major breakthrough of this device is that it can control the braking torque through the modification of some geometrical parameters, L and R, and through the activation of more than one hydraulic cylinder together with the pressure. The output shaft of the PTO is able to rotate at different continuous rated speed through the actuation on a specific control valve at the inlet of the hydraulic motor. Tests to check the behavior of the PTO related to the smoothening of the power output and concerning the time needed to increase the high pressure and the time available after the accumulation of some quantity of energy in different initial conditions are presented.

scholarly journals Investigations of Hydraulic Power Take-Off Unit Parameters Effects on the Performance of the WAB-WECs in the Different Irregular Sea States

2021 ◽  
Vol 9 (8) ◽  
pp. 897
Author(s):  
Mohd Afifi Jusoh ◽  
Zulkifli Mohd Yusop ◽  
Aliashim Albani ◽  
Muhamad Zalani Daud ◽  
Mohd Zamri Ibrahim
Keyword(s):  
Simulation Study ◽  
Wave Energy ◽  
Electrical Power ◽  
Hydraulic Cylinder ◽  
Wave Energy Conversion ◽  
Hydraulic Motor ◽  
Complete Model ◽  
Hydraulic Power ◽  
Effective Power ◽  
Energy Conversion Systems

Hydraulic power take-off (HPTO) is considered to be one of the most effective power take-off schemes for wave energy conversion systems (WECs). The HPTO unit can be constructed using standard hydraulic components that are readily available from the hydraulic industry market. However, the construction and operation of the HPTO unit are more complex rather than other types of power take-off, as many components parameters need to be considered during the optimization. Generator damping, hydraulic motor displacement, hydraulic cylinder and accumulator size are among the important parameters that influence the HPTO performance in generating usable electricity. Therefore, the influence of these parameters on the amount of generated electrical power from the HPTO unit was investigated in the present study. A simulation study was conducted using MATLAB/Simulink software, in which a complete model of WECs was developed using the Simscape fluids toolbox. During the simulation, each parameters study of the HPTO unit were separately manipulated to investigate its effects on the WECs performance in five different sea states. Finally, the simulated result of the effect of HPTO parameters on the amount of generated electrical power from the HPTO unit in different sea states is given and discussed.

An Efficient Convex Formulation for Model-Predictive Control on Wave-Energy Converters1

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Qian Zhong ◽  
Ronald W. Yeung
Keyword(s):  
Model Predictive Control ◽  
Cost Function ◽  
Predictive Control ◽  
Wave Energy ◽  
Reactive Power ◽  
Primary Concern ◽  
Penalty Term ◽  
Irregular Wave ◽  
Wave Energy Converters ◽  
Hard Constraints

Model-predictive control (MPC) has shown its strong potential in maximizing energy extraction for wave-energy converters (WECs) while handling hard constraints. However, the computational demand is known to be a primary concern for applying MPC in real time. In this work, we develop a cost function in which a penalty term on the slew rate of the machinery force is introduced and used to ensure the convexity of the cost function. Constraints on states and the input are incorporated. Such a constrained optimization problem is cast into a Quadratic Programming (QP) form and efficiently solved by a standard QP solver. The current MPC is found to have good energy-capture capability in both regular and irregular wave conditions, and is able to broaden favorably the bandwidth for capturing wave energy compared to other controllers in the literature. Reactive power required by the power-take-off (PTO) system is presented. The effects of the additional penalty term are discussed.

The Principle of a Three-DOF Mechanism for Wave Energy Absorption

2016 ◽  
Author(s):  
Weixing Chen ◽  
Xiangdun Meng ◽  
Feng Gao
Keyword(s):  
Wave Energy ◽  
Power Output ◽  
Wave Power ◽  
Spherical Joint ◽  
Hydraulic Power ◽  
Wave Energy Converters ◽  
Major Class ◽  
Absorption Performance ◽  
Heave Motion ◽  
Four Bar Linkage

As we all know, oceans have great wave power, and many types of wave energy converters (WECs) have been invented so far. Oscillating body systems are a major class of WECs which almost only have one degree of freedom (DOF). This paper presents a three-DOF mechanism which can extract the wave power from any wave directions. The three-DOF mechanism mainly consists of a four-bar linkage and a spherical joint, which are used to capture the heave motion and the pitch and roll motions of the oscillating body respectively. The power conversion principle of the WEC is proposed and the kinematics of the mechanism is derived. Hydraulic power take-off (PTO) systems are used, which are simplified as constant torques in this study. In the end, the power absorption performance of the WEC is presented based on the system dynamics. The results show that the rated power output of the WEC is 4.3MW, and the power output of the WEC is dependent on the wave directions.

Speed control of oil-hydraulic power take-off system for oscillating body type wave energy converters

2016 ◽  
Vol 97 ◽  
pp. 769-783 ◽  
Author(s):  
José F. Gaspar ◽  
Mojtaba Kamarlouei ◽  
Ashank Sinha ◽  
Haitong Xu ◽  
Miguel Calvário ◽  
...  
Keyword(s):  
Wave Energy ◽  
Speed Control ◽  
Body Type ◽  
Hydraulic Power ◽  
Type Wave ◽  
Wave Energy Converters ◽  
Energy Converters

scholarly journals DESIGN OF AN OCEAN WAVE ENERGY CONVERTER – THE PRELIMINARY STUDY

2020 ◽  
pp. 1-4
Author(s):  
UZAIR JAUHAR ALI ◽  
SHARUL SHAM BIN DOL ◽  
ABID ABDUL AZEEZ
Keyword(s):  
Kinetic Energy ◽  
United Arab Emirates ◽  
Wave Energy ◽  
Hydraulic Motor ◽  
Energy Converter ◽  
Hybrid Device ◽  
Wave Energy Converters ◽  
Ocean Wave Energy ◽  
The Earth ◽  
Preliminary Study

Wave Energy Converters (WEC) are devices that harvest the different energies that are associated with moving waves, such as kinetic energy and potential energy, and converting them into useful mechanical and electrical energies. Considering that the ocean and sea are covering around 71 percent of the earth, it is unavoidable to consider it as the main source of renewable energy. This report starts with reviewing a few of the most recent WECs. In the analysis section, it shows a device that functions using pistons to run a hydraulic motor, which then runs a generator in a system. The device is further modified by attaching a rotating mass, which is directly connected to a generator. It is a hybrid device using technologies of both the Pelamis and the Penguin. The power output calculated for the system is 177 kW, which is quiet reasonable considering the wave conditions at Fujairah’s sea shore in United Arab Emirates.

Design tradeoffs of an oil-hydraulic power take-off for wave energy converters

2018 ◽  
Vol 129 ◽  
pp. 245-259 ◽  
Author(s):  
José F. Gaspar ◽  
Miguel Calvário ◽  
Mojtaba Kamarlouei ◽  
C. Guedes Soares
Keyword(s):  
Wave Energy ◽  
Hydraulic Power ◽  
Wave Energy Converters ◽  
Design Tradeoffs ◽  
Energy Converters
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