scholarly journals Design and Simulation of a Novel Mechanical Power Take-Off for a Two-Body Wave Energy Point Absorber

2018 ◽  
Author(s):  
Xiaofan Li ◽  
Chien-An Chen ◽  
Qiuchi Xiong ◽  
Robert Parker ◽  
Lei Zuo
Keyword(s):  
Frequency Domain ◽  
Output Power ◽  
Wave Energy ◽  
Time Domain ◽  
Wave Energy Converter ◽  
Mechanical Power ◽  
Total Output ◽  
Test Machine ◽  
Mechanical Motion ◽  
Energy Converter

In this paper, a two-body self-react wave energy converter with a novel mechanical Power Take-off (PTO) is introduced. The PTO rectifies the mechanical motion and regulates the flow with a mechanism called Mechanical Motion Rectifier (MMR), which converts the reciprocating motion of the ocean wave into unidirectional rotation of the generator. The overall system is analyzed in both time and frequency domain. In time domain, the piecewise non-linear dynamic model of the MMR PTO is derived, and parameters that could significantly influence the MMR property is extracted. By building the model into WEC-Sim, a time domain wave energy converter (WEC) simulation tool, to simulate and evaluate the performance of the PTO. In addition, the system is modelled as a two-body vibration system for frequency domain analysis in order to further investigate and optimize the proposed wave energy converter. The tunable parameters within the system, including the equivalent mass, the equivalent damping coefficient, and the PTO stiffness, are discussed based on the criteria of maximization of the total output power. To verify the theoretical analysis, a bench test prototype is developed and tested on a hydraulic test machine. The experimental results in line with the derived model and can be used for reasonable estimation on the output power of the proposed system in real ocean conditions.

scholarly journals The performance of the Mocean M100 wave energy converter described through numerical and physical modelling

2020 ◽  
Vol 3 (1) ◽  
pp. 11-19
Author(s):  
J. Cameron McNatt ◽  
Christopher H. Retzler
Keyword(s):  
Frequency Domain ◽  
Wave Energy ◽  
Time Domain ◽  
Numerical Models ◽  
Average Power ◽  
Physical Modelling ◽  
Wave Energy Converter ◽  
Domain Model ◽  
Energy Converter ◽  
Cost Of Energy

Mocean Energy has designed a 100-kW hinged-raft wave energy converter (WEC), the M100, which has a novel geometry that reduces the cost of energy by improving the ratios of power per size and power per torque. The performance of the M100 is shown through the outputs of frequency-domain and time-domain numerical models, which are compared with those from 1/20th scale wave-tank testing. Results show that for the undamped, frequency-domain model, there are resonant peaks in the response at 6.6 and 9.6 s, corresponding to wavelengths that are 1.9 and 3.7 times longer than the machine. With the inclusion of power-take-off and viscous damping, the power response as a function of frequency shows a broad bandwidth and a hinge flex amplitude of 12-20 degrees per meter of wave amplitude. Comparison between the time-domain model and physical data in a variety of sea states, up to a significant wave height of 4.5 m, show agreements within 10% for average power absorption, which is notable because only simple, nonlinear, numerical models were used. The M100 geometry results in a broad-banded, large amplitude response due to its asymmetric shape, which induces coupling between modes of motion.

scholarly journals Advection-Based Coordinated Control for Wave-Energy Converter Array

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3567
Author(s):  
Hong Li ◽  
Bo Zhang ◽  
Li Qiu ◽  
Shiyu Chen ◽  
Jianping Yuan ◽  
...  
Keyword(s):  
Output Power ◽  
Wave Energy ◽  
Control Method ◽  
Initial Conditions ◽  
Coordinated Control ◽  
Wave Energy Converter ◽  
Total Output ◽  
Energy Converter ◽  
Storage Unit ◽  
Additional Energy

This paper presents a coordinated control based on the advection consensus control algorithm to implement power dispatch for each wave-energy converter (WEC) in a WEC array. Under unbalanced conditions, the proposed algorithm is applied in order to control each WEC to output power coordinately, to enable the total output power of the WEC array to satisfy the time-varying load requirements. The purpose of the additional energy storage unit on each WEC is to smooth the power output of each WEC and to obtain more margin. Case studies include the demonstration of some simulations and experiments, and the results show that the WEC array under the proposed control method can accurately respond to the demand for power supply under unbalanced initial conditions.

Design and Analysis of a Two-Body Wave Energy Converter With Mechanical Motion Rectifier

2016 ◽  
Author(s):  
Xiaofan Li ◽  
Changwei Liang ◽  
Lei Zuo
Keyword(s):  
Output Power ◽  
Relative Motion ◽  
Wave Energy ◽  
Average Output Power ◽  
Body Wave ◽  
Wave Energy Converter ◽  
Mechanical Motion ◽  
Energy Converter ◽  
Average Output ◽  
Wave Condition

The design and dynamic analysis of a two-body wave energy converter with 50W average output power is presented in this paper. The wave energy is extracted through the relative motion between a floating buoy and a submerged body, both oscillating in the heave direction. A ball screw system is used to convert the linear relative motion into bidirectional rotation of the screw. Moreover, a mechanical motion rectifier (MMR) is used in the power take-off (PTO) design and convert the bidirectional rotation into unidirectional rotation of generator by using two one-way bearings in the gear system. The dynamic equation of this two-body wave energy converter is established by considering the engagement and disengagement of the one-way bearings in the PTO system. The simulation results in the regular and irregular waves are presented and the average output power of the proposed wave energy converter under different wave condition are estimated.

Time Domain Modeling and Power Output for a Heaving Point Absorber Wave Energy Converter

2014 ◽  
Author(s):  
Jeremiah Pastor ◽  
Yucheng Liu
Keyword(s):  
Frequency Domain ◽  
Wave Energy ◽  
Time Domain ◽  
Power Output ◽  
Time Domain Analysis ◽  
Domain Analysis ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
Power Absorption ◽  
Point Absorber

This paper presents, assesses, and optimizes a point absorber wave energy converter (WEC) through numerical modeling, simulation, and analysis in time domain. Wave energy conversion is a technology especially suited for assisting in power generation in the offshore oil and gas platforms. A linear frequency domain model is created to predict the behavior of the heaving point absorber WEC system. The hydrodynamic parameters are obtained with AQWA, a software package based on boundary element methods. A linear external damping coefficient is applied to enable power absorption and an external spring force is introduced to tune the point absorber to the incoming wave conditions. The external damping coefficient and external spring forces are the control parameters, which need to be optimized to maximize the power absorption. Two buoy shapes are tested and a variety of diameters and drafts are compared. Optimal shape, draft, and diameter of the model are then determined to maximize its power absorption capacity. Based on the results generated from the frequency domain analysis, a time domain analysis was also conducted to derive the responses of the WEC in the hydrodynamic time response domain. The time domain analysis results allowed us to estimate the power output of this WEC system.

Novel hydraulic mechanism-based output power regulation for the wave energy converter

2021 ◽  
Vol 110 ◽  
pp. 102587
Author(s):  
Dazhou Geng ◽  
Yang Zheng ◽  
Qijuan Chen ◽  
Xuhui Yue ◽  
Donglin Yan
Keyword(s):  
Output Power ◽  
Wave Energy ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
Power Regulation ◽  
Hydraulic Mechanism

scholarly journals Deep Learning for Wave Energy Converter Modeling Using Long Short Term Memory

2021 ◽  
Author(s):  
Seyed Milad Mousavi ◽  
Majid Ghasemi ◽  
Mahsa Dehghan Manshadi ◽  
Amir Mosavi
Keyword(s):  
Wind Speed ◽  
Output Power ◽  
Wave Energy ◽  
Short Term Memory ◽  
Ocean Waves ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
Short Term ◽  
Term Memory ◽  
Long Short Term Memory

Accurate forecasts of ocean waves energy can not only reduce costs for investment but it is also essential for management and operation of electrical power. This paper presents an innovative approach based on the Long Short Term Memory (LSTM) to predict the power generation of an economical wave energy converter named “Searaser”. The data for analyzing is provided by collecting the experimental data from another study and the exerted data from numerical simulation of searaser. The simulation is done with Flow-3D software which has high capability in analyzing the fluid solid interactions. The lack of relation between wind speed and output power in previous studies needs to be investigated in this field. Therefore, in this study the wind speed and output power are related with a LSTM method. Moreover, it can be inferred that the LSTM Network is able to predict power in terms of height more accurately and faster than the numerical solution in a field of predicting. The network output figures show a great agreement and the root mean square is 0.49 in the mean value related to the accuracy of LSTM method. Furthermore, the mathematical relation between the generated power and wave height was introduced by curve fitting of the power function to the result of LSTM method.

Modeling and Experiment of a Novel Micro Wave Energy Converter

2017 ◽  
Vol 863 ◽  
pp. 175-182
Author(s):  
Yi Ming Zhu ◽  
Zi Rong Luo ◽  
Zhong Yue Lu ◽  
Jian Zhong Shang
Keyword(s):  
Output Power ◽  
Wave Energy ◽  
Mechanical Energy ◽  
Vertical Motion ◽  
Electrical Energy ◽  
Wave Energy Converter ◽  
Design Parameters ◽  
Energy Converter ◽  
Drive Power ◽  
Continuous Rotation

This paper proposed a novel micro wave energy converter which can convert irregular wave energy into rotating mechanical energy, then into electrical energy. The device consists of an energy absorption part and an energy conversion part. In details, the blades are installed on the absorber circumferentially and averagely, which are capable of converting the vertical motion of the surface body to continuous rotation of the absorber and leading to a great increase in efficiency. A physical prototype was built to test the performance of the novel generator and optimize the design parameters. In the experiment part, a linear motion electric cylinder was used as the drive power to provide the heaving motion for the device. And the experiment platform was built for modeling a marine environment. Also, a data acquisition program was edited in Labview. Thus, the experiment analyzed the influence of amplitude, frequency, blade angle and resistance value to the output power, and then obtained the optimum parameters combination which can maximize the value of the output power. The result will provide reference for the device’s further application.

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