Closed-Form Solutions for Electroacoustic Wave Energy Harvesting in a Coupled Plate-Harvester System

2016 ◽  
Author(s):  
Amir Darabi ◽  
Michael Leamy
Keyword(s):  
Point Source ◽  
Wave Energy ◽  
Piezoelectric Layer ◽  
Electrical Power ◽  
Infinite Plate ◽  
Electrical Circuit ◽  
Form Solution ◽  
Host Layer ◽  
Piezoelectric Disk ◽  
Source Excitation

This paper introduces an analytical framework for predicting wave energy harvested by a circular piezoelectric layer from a harmonic point source excitation. The explored acoustic system analyzes a circular piezoelectric disk attached to an infinite host domain. An harmonic point source is located away from the piezoelectric disk on the infinite host layer. The analysis approach decomposes the system into two subdomains, the piezoelectric disk and an infinite plate, which are then separately analyzed. In contrast to traditional analysis methods for such systems (a sandwich of layers with different dimensions), this technique uses internal interaction forces between the different subdomains to find a close-form solution for the vibration of propagating waves over the entire field. In addition, the voltage generated by the harvester is calculated by using coupled electromechanical equations. The analysis is validated by comparing response quantities and frequency response functions at different points on the piezoelectric circular layer and host layers to those predicted using COMSOL simulations, which document good agreement. Analysis of this system is an important stepping stone to the next goal, which is optimization of energy captured from the propagating wave by designing boundary walls (reflector) on the host layer which focus the energy of the wave onto the piezoelectric domain. This focused energy can then be transferred to the electrical power by via a piezoelectric layer through an electrical circuit.

Multiple Scattering of Acoustoelastic Waves in Thin Plates for Enhanced Energy Harvesting

2016 ◽  
Author(s):  
Amir Darabi ◽  
Michael Leamy
Keyword(s):  
Energy Harvesting ◽  
Multiple Scattering ◽  
Wave Energy ◽  
Focal Point ◽  
Mechanical Energy ◽  
Single Point ◽  
Infinite Plate ◽  
Electrical Circuit ◽  
Thin Plates ◽  
Optimization Study

Harvesting of acoustoelastic wave energy in thin plates and other structures has recently gained attention from the energy harvesting community. To enhance the wave power generated, researchers have investigated metamaterial-inspired concepts to include funnels, mirrors, and defect-based resonators introduced in the metamaterial’s bandgap. Many of these concepts have been demonstrated experimentally using arrangements of cylindrical stubs mounted on the surface of a thin plate, where such stubs scatter plane and cylindrical waves in such a way as to focus mechanical energy. To support these studies, the authors have recently introduced an experimentally-verified analytical framework for investigating the coupled electromechanical response of a single circular piezoelectric harvester adhered to an infinite plate and excited by a distant harmonic point source. This paper extends these ideas to consider a similar physical system with the addition of multiple cylindrical inclusions. These additions require development of an electromechanically-coupled, multiple scattering formulation of significantly increased complexity. The formulation also includes an electrical circuit model for generating electrical current from incident waves interacting with the piezoelectric domain. Following development, the formulation is applied to the determination of optimal arrangements of scatterers which maximize the electrical power generated. Specifically, an optimization study is carried-out in which twenty-five scatterers are first placed in a semi-elliptical arrangement with the aim of focusing wave energy from one elliptical focus (i.e., source location) onto the other. It is known from past studies that additional side lobes are generated due to truncation of the ellipse, and thus not all of the energy can be focused at single point, as desired. To improve upon this situation, an optimization study is performed in which the aspect ratio of the ellipse is varied, with the goal of optimizing the power harvested from the focal point. Results from the optimization studies show conclusively that the side lobes can in fact be minimized, and that harvested power can be significantly improved.

scholarly journals Damping Studies on PMLG-Based Wave Energy Converter under Oceanic Wave Climates

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 920
Author(s):  
Yue Hong ◽  
Irina Temiz ◽  
Jianfei Pan ◽  
Mikael Eriksson ◽  
Cecilia Boström
Keyword(s):  
Wave Energy ◽  
Energy Production ◽  
Full Range ◽  
Electrical Power ◽  
Damping Coefficient ◽  
Irregular Wave ◽  
Ocean Wave Energy ◽  
Optimal Damping ◽  
The Impact

Wave energy converters (WECs), which are designed to harvest ocean wave energy, have recently been improved by the installation of numerous conversion mechanisms; however, it is still difficult to find an appropriate method that can compromise between strong environmental impact and robust performance by transforming irregular wave energy into stable electrical power. To solve this problem, an investigation into the impact of varied wave conditions on the dynamics of WECs and to determine an optimal factor for WECs to comply with long-term impacts was performed. In this work, we researched the performance of WECs influenced by wave climates. We used a permanent magnet linear generator (PMLG)-based WEC that was invented at Uppsala University. The damping effect was first studied with a PMLG-type WEC. Then, a group of sea states was selected to investigate their impact on the power production of the WEC. Two research sites were chosen to investigate the WEC’s annual energy production as well as a study on the optimal damping coefficient impact. In addition, we compared the WEC’s energy production between optimal damping and constant damping under a full range of sea states at both sites. Our results show that there is an optimal damping coefficient that can achieve the WEC’s maximum power output. For the chosen research sites, only a few optimal damping coefficients were able to contribute over 90% of the WEC’s annual energy production. In light of the comparison between optimal and constant damping, we conclude that, for specific regions, constant damping might be a better choice for WECs to optimize long-term energy production.

Estimation of Electrical-Wave Power in Merang Shore, Terengganu, Malaysia

2014 ◽  
Vol 66 (2) ◽  
Author(s):  
Jaswar Jaswar ◽  
C. L. Siow ◽  
A. Maimun ◽  
C. Guedes Soares
Keyword(s):  
Renewable Energy ◽  
Wave Energy ◽  
Electrical Power ◽  
Green Technology ◽  
Solar Photovoltaic ◽  
Oscillating Water Column ◽  
Mean Wave Period ◽  
Point Absorbers ◽  
The Mean ◽  
Wave Converter

Malaysian government introduced Small Renewable Energy Power (SREP) Program such as biomass, biogas, and municipal solid waste, solar photovoltaic and mini-hydroelectric facilities in 2001. In year 2010, the energy generated by biomass was achieved 18 MW and mini hydro also successes to generate around 23 MW. Green Technology and Water Malaysia are targeted by Ministry of Energy to achieve cumulative renewable energy capacity around 2080 MW at year 2020 and 21.4 GW at year 2050. This paper discusses the possibility to utilize ocean wave in Merang shore, Terengganu, Malaysia. The literature reviewed available technologies used to convert wave energy to electricity which are developing currently. The available technologies reviewed here are attenuator, overtopper, point absorbers, oscillating wave surge converter and oscillating water column. The work principle of the device was covered. Finally, the sea condition in Malaysia also studied to analyze the possibility to utilize the wave energy by using the available technologies. It is found that the mean wave height is 0.95 meter and the mean wave period is 3.5 second in the Merang shore, Terengganu, Malaysia. Attenuator type wave converter developed by Wave Star is considered as one of the possible devices to be installed at the location. From the calculation, it is obtained that the total rate electrical power possible to grid is 649 MWh a year if only one set of C5 Wave star device is installed on Merang shore, Terengganu.

scholarly journals Performance assessment of a small-size ocean wave energy harvester

2019 ◽  
Vol 283 ◽  
pp. 05006
Author(s):  
Yongjie Sang ◽  
Bertrand Dubus
Keyword(s):  
Electrical Power ◽  
Vertical Motion ◽  
Electrical Energy ◽  
Ocean Waves ◽  
Electrical Circuit ◽  
Optimal Choice ◽  
Ocean Wave ◽  
Unit Weight ◽  
Ocean Energy ◽  
Ocean Wave Energy

A lightweight electromechanical device is studied to harvest energy of ocean waves and supply electrical power to small-size ocean observation equipment such as sonobuoys. It is composed of a magnet fixed to the floating housing which follows the motion of the ocean surface and a moving coil connected to the case via a flexible spring. As the floating housing follows the vertical motion of water surface, a voltage is induced in the coil due to relative velocity between the coil and the magnet, and kinetic energy of the ocean wave is converted into electrical energy. Full bridge rectifying circuit and smoothing capacitor are used to convert AC voltage to constant voltage. Single degree of freedom electromechanical model of the prototype transducer (LGT-4.5 geophone) is developed and simulated with an electrical circuit software to predict energy harvesting performance. Vibration experiments are also performed with a shaker to validate transducer model and quantify output voltage. Parametric analysis is conducted to identify optimal choice of capacitance in terms of maximum stored energy and minimum charging time. This device is simple and small size relative to ocean wavelength compared to classical linear permanent magnetic generator used in offshore power plant. Its power generation per unit weight is compared to larger scale ocean energy converters.

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