A Mathematical Model for a Gyroscopic Ocean-Wave Energy Converter

2013 ◽  
Author(s):  
H. Murakami ◽  
O. Rios
Keyword(s):  
Mathematical Model ◽  
Power Generation ◽  
Wave Energy ◽  
Ocean Waves ◽  
Ocean Wave ◽  
Scale Model ◽  
Design Parameters ◽  
Wave Power ◽  
Power Generator ◽  
Ocean Wave Energy

Global attempts to increase generation of clean and reproducible energy have contributed to considerable progress in ocean-wave power-generation technologies. The efficiency of ocean-wave energy converters has improved by almost an order of magnitude in the last decade. In this report, we consider a floating-type gyroscopic ocean-wave power-generator that has proven to generate 50 kW in a prototype test conducted by a Japanese company in 2012. A gyroscopic power generator consists of a buoy, a gimbal, and spinning rotors mounted on a gimbal. The gimbal is installed on the deck of the buoy and rotates when the buoy oscillates or rocks by ocean waves. The gimbal axis is connected to an electric generator. The objectives of our research are to understand quantitatively the mechanisms of gyroscopic ocean-wave power-generators and to improve the component design of the generator to maximize power output. To this end, we develop a mathematical model and a scale model of a gyroscopic ocean-wave power-generator. This integrated approach is to numerically simulate power generation and to clarify the effect of relevant design parameters.

A Mathematical Model With Preliminary Experiments of a Gyroscopic Ocean Wave Energy Converter

2015 ◽  
Author(s):  
Hidenori Murakami ◽  
Oscar Rios ◽  
Ardavan Amini
Keyword(s):  
Mathematical Model ◽  
Power Generation ◽  
Wave Energy ◽  
Equations Of Motion ◽  
Energy Generation ◽  
Wave Energy Converter ◽  
Ocean Wave ◽  
Scale Model ◽  
Energy Converter ◽  
Ocean Wave Energy

Global attempts to increase generation of clean and reproducible natural energy have greatly contributed to the progress of solar, wind, biomass, and geothermal energy generation. To meet the goal set by the Renewable Portfolio Standards (RPS) in the United States, it is advisable for several of the coastal states to tap into the least explored resource: ocean-wave energy. There are many advantages to ocean-wave energy generation. First, the energy per unit area is 20 to 30 times larger compared with solar and five to ten times larger when compared to wind energy. Second, waves are more easily predicted than wind. Currently, there are several challenges with capturing ocean energy: With respect to the environment, noise pollution and effects on marine life need to be taken into consideration; with respect to design, ocean-wave power generators need to withstand large waves due to hurricanes and be designed to lessen visual pollution. There are various methods and devices used to capture ocean wave energy. Point absorbers, such as PowerBuoy, can harness vertical or heaving motion into electricity while attenuators like Pelamis use the induced movement of its joints from the incoming waves. Unfortunately, many have few parameters that can be varied to optimize power generation and or suffer from the various challenges mentioned above. The gyroscopic ocean wave energy converter harnesses the rocking or pitching motion induced by the ocean waves and converts it into rotary motion that is then fed to a generator. Furthermore, it is a fully enclosed floating device that has several parameters that can be varied to optimize power output. Previous work has demonstrated the viability of such a device, but the theoretical modeling of these converters is still in its infancy compared to that of other ocean wave energy converters. The objective of the research presented is to fully understand the mechanisms of power generation in the gyroscopic ocean wave energy converter. Using the moving frame method, a mathematical model of the device is developed. The nonlinear equations of motion are derived through the use of this novel method and then solved numerically. The results are then used to optimize the system and identify key parameters and their effect on the output power generated. Additionally, the resulting equations serve as a tool for identifying an appropriate control strategy for the system. Finally, a scale model of a gyroscopic ocean wave energy converter is developed to validate the equations of motion that have been derived.

The Study on Technology of Ocean Wave Energy Generation

2013 ◽  
Vol 724-725 ◽  
pp. 818-822
Author(s):  
Sheng Ye ◽  
Wei Jun Wang ◽  
Bing Li ◽  
Long Bo Mao
Keyword(s):  
Power Generation ◽  
Wave Energy ◽  
Energy Generation ◽  
Ocean Wave ◽  
Wave Power ◽  
Ocean Wave Energy ◽  
New Energy ◽  
Day By Day ◽  
Generation Technology ◽  
Wave Power Generation

As a source of a clean green renewable new energy, wave power generation is paid much attention by more countries while the decrease of the amount of the energy day by day. The conversion technology in the field of wave energy has tended to mature. Now it is running into commercial exploitation leve1. In this paper, the fundamental principles of ocean wave energy generation technology are presented. The classification and present situation of ocean wave power generation device are introduced. At last, some possible directions and prospects of wave energy generation technology are expatiated.

scholarly journals A Review of the Optimization Design and Control for Ocean Wave Power Generation Systems

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 102
Author(s):  
Juanjuan Wang ◽  
Zhongxian Chen ◽  
Fei Zhang
Keyword(s):  
Power Generation ◽  
Wave Energy ◽  
Optimization Design ◽  
Electrical Energy ◽  
Ocean Waves ◽  
Ocean Wave ◽  
Wave Power ◽  
Optimization Control ◽  
Power Generation Systems ◽  
Wave Power Generation

Ocean wave power generation techniques (converting wave energy into electrical energy) have been in use for many years. The objective of this paper is to review the design, control, efficiency, and safety of ocean wave power generation systems. Several topics are discussed: the current situation of ocean wave power generation system tests in real ocean waves; the optimization design of linear generator for converting ocean wave energy into electrical energy; some optimization control methods to improve the operational efficiency of ocean wave power generation systems; and the current policy and financial support of ocean wave power generation in some countries. Due to the harsh ocean environment, safety is another factor that ocean wave power generation systems will face. Therefore, before the conclusion of this review, a damping coefficient optimization control method based on the domain partition is proposed to improve the efficiency and safety of ocean wave power generation systems.

scholarly journals Ocean Wave Energy Utilization using Magnetostrictive Vibrational Power Generator

2014 ◽  
Vol 70 (2) ◽  
pp. I_1306-I_1310
Author(s):  
Takehis SAITOH ◽  
Junpei WAGATSUM ◽  
Toshiyuki UENO ◽  
Shot KITA
Keyword(s):  
Wave Energy ◽  
Energy Utilization ◽  
Ocean Wave ◽  
Power Generator ◽  
Ocean Wave Energy

scholarly journals A Wave Energy Extraction System in Experimental Flume

2016 ◽  
Vol 2016 ◽  
pp. 1-4
Author(s):  
Qin Guodong ◽  
Pang Quanru ◽  
Chen Zhongxian
Keyword(s):  
Wave Energy ◽  
Ocean Waves ◽  
High Energy ◽  
Ocean Wave ◽  
High Energy Density ◽  
Extraction System ◽  
Energy Extraction ◽  
Linear Generator ◽  
Ocean Wave Energy ◽  
Experimental Flume

Ocean wave energy is a high energy density and renewable resource. High power conversion rate is an advantage of linear generators to be the competitive candidates for ocean wave energy extraction system. In this paper, the feasibility of a wave energy extraction system by linear generator has been verified in an experimental flume. Besides, the analytical equations of heaving buoy oscillating in vertical direction are proposed, and the analytical equations are proved conveniently. What is more, the active power output of linear generator of wave energy extraction system in experimental flume is presented. The theoretical analysis and experimental results play a significant role for future wave energy extraction system progress in real ocean waves.

Hydrocavitation piezoelectric ocean wave energy harvesting

2021 ◽  
pp. 1-10
Author(s):  
Francisco Arias ◽  
Salvador De Las Heras
Keyword(s):  
Wave Energy ◽  
Low Cost ◽  
Electrical Energy ◽  
Ocean Waves ◽  
Ocean Wave ◽  
Mechanical Parts ◽  
Energy Harvesters ◽  
Ocean Wave Energy ◽  
Piezoelectric Layers ◽  
Local Pressures

Abstract The possibility to convert the ocean wave energy into electrical energy by piezoelectric layers has excited the imagination of ocean wave energy conversion designers for decades owing to its relative robustness (no mechanical parts are needed), the capability to cover large areas and its relative low cost. Unfortunately, the very poor efficiency featured by piezoelectric layers in application of ocean waves has prevented its application even as energy harvester. Here, the possibility to induce hydrocavitation and then working with more higher local pressures for substantial efficiency enhancement is discussed. Utilizing a simplified geometrical and physical model and the linear and potential theory, a first theoretical estimation for the energy enhancement driven by hydrocavitation was calculated. It was found that the power could be enhanced several orders of magnitude which, although still rather low, however, the enhanced electric outputs can be used now as energy harvesters. Additional R&D is encouraged in order to explore the possibilities to harness hydrocavitation to enhance piezoelectric converters.

Development of Wave Power Generation Technology

2012 ◽  
Vol 512-515 ◽  
pp. 905-909
Author(s):  
Cui Ping Kuang ◽  
Peng Chen Liu ◽  
Yi Pan ◽  
Jie Gu
Keyword(s):  
Power Generation ◽  
Renewable Energy ◽  
Wave Energy ◽  
Wave Power ◽  
Existing Problems ◽  
Ocean Wave Energy ◽  
Power Generation Technology ◽  
Increasing Demand ◽  
Generation Technology ◽  
Wave Power Generation

With the increasing demand of energy, as a clean green renewable energy, ocean wave energy is paid much attention by the countries especially those along coasts. So far, wave power generation technology has experienced decades of development. In this paper, the development and the main wave power generation devices are introduced, moreover, the latest applications of wave energy and existing problems on wave power generation technology are presented.

A New Flapping-Hydrofoil Wave Power Generating Unmanned Ocean Vehicle

2016 ◽  
Author(s):  
Tao Sun ◽  
Jiangbin Zhao ◽  
Xinping Yan ◽  
Pengpeng Xu
Keyword(s):  
Wave Energy ◽  
Energy Harvester ◽  
Clean Energy ◽  
Sea Surface ◽  
Ocean Wave ◽  
Wave Power ◽  
Ocean Science ◽  
Ocean Wave Energy ◽  
Offshore Engineering ◽  
Further Development

To solve the issue of the energy supply for unmanned ocean vehicles, the ocean wave energy as an abundant and widely distributed renewable clean energy, provides a feasible way. This paper proposes a flapping-hydrofoil method applied to unmanned ocean vehicles, harnessing the ocean wave energy to generate power. The structure of the flapping-hydrofoil wave energy harvester is presented, including the internal transmission device and the design of the hydrofoil. Then the operation modes (buoyancy drive and electric drive) and the application prospects (operating on and under the sea surface) of the flapping-hydrofoil wave energy ocean vehicle are also discussed, with the sincere expectations of further development of the ocean science and technology as well as offshore engineering.

Assessment of the Motion of Wave Power Generation by Water Tank Test

2017 ◽  
Author(s):  
Takero Yoshida ◽  
Daisuke Kitazawa ◽  
Yoichi Mizukami
Keyword(s):  
Power Generation ◽  
Ocean Waves ◽  
Test Site ◽  
Video Camera ◽  
Scale Model ◽  
Wave Power ◽  
Test Case ◽  
Water Tank ◽  
Waves And Currents ◽  
Wave Power Generation

Installing devices of marine renewable energy is planned off Kamaishi city, Iwate prefecture, Japan. A device of wave power generation was settled at this site as a test case. It is important to coexist the power generation device and local fishermen. Since Kamaishi is known as a good fishing area, acceptance of fishermen is required to run the wave power generation at the test site. Especially, local fishermen in Kamaishi have a concern about how wave power generation moves along with ocean waves and currents. To acquire an acceptance from local fishermen in terms of setting wave power generation, a model test was conducted to understand the device of wave power generation. It consists of float, spar, middle float, gimbal mechanism and anchor. Middle float, gimbal mechanism and anchor are mooring. The submerged weights of the model almost satisfy the targeted values calculated by the scale ratio and actual submerged weights. The experiment was conducted for 1/125 scale model at a water tank in marine environmental and ecosystem laboratory, the university of Tokyo. We monitored the motion of the model under several conditions of regular waves and currents. The motions of the model were recorded by a video camera and were analyzed. The model was moved with respect to the surface waves and currents. We assessed the motions of the float based on the experiment. The experimental results will be used to explain local fishermen.

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