Ocean wave energy overview and research at Oregon State University

Abstract:A novel tuned heave plate energy-harvesting system (THPEH) is presented for the motion suppressing and energy harvesting of a semi-submersible platform. This THPEH system is designed based on the principle of a tuned mass damper (TMD) and is composed of spring supports, a power take-off system (PTO) and four movable heave plates. The permanent magnet linear generators (PMLG) are used as the PTO system in this design. A semi-submersible platform operating in the South China Sea is selected as the research subject for investigating the effects of the THPEH system on motion reduction and harvesting energy through numerical simulations. The numerical model of the platform and the THPEH system, which was established based on hydrodynamic analysis, is modified and validated by the results of the flume test of a 1:70 scale model. The effects of the parameters, including the size, the frequency ratio and the damping ratio of the THPEH system, are systematically investigated. The results show that this THPEH system, with proper parameters, could significantly reduce the motions of the semi-submersible platform and generate considerable power under different wave conditions.

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of a Tuned Heave Plate Energy-Harvesting System of a Semi-Submersible Platform

Liu

Liang

2016

“…Direct-drive WEC (D-DWEC) systems, each of which comprises merely a wave energy capture unit and a linear generator, have aroused attention and discussion to a certain extent because they improve the conversion efficiency and reduce the complexity and device volume of WECs. Meanwhile, several new linear generators for D-DWECs have been investigated, such as conventional permanent-magnet (PM) synchronous linear generators, transverse-flux PM generators, magnetic flux-switching linear generators, and linear magnetic-geared generators [7,8].…”

Section: Introductionmentioning

confidence: 99%

Design and Experiment Analysis of a Direct-Drive Wave Energy Converter with a Linear Generator

Zhang

2018

Abstract:Coastal waves are an abundant nonpolluting and renewable energy source. A wave energy converter (WEC) must be designed for efficient and steady operation in highly energetic ocean environments. A direct-drive wave energy conversion (D-DWEC) system with a tubular permanent magnet linear generator (TPMLG) on a wind and solar photovoltaic complementary energy generation platform is proposed to improve the conversion efficiency and reduce the complexity and device volume of WECs. The operating principle of D-DWECs is introduced, and detailed analyses of the proposed D-DWEC's floater system, wave force characteristics, and conversion efficiency conducted using computational fluid dynamics are presented. A TPMLG with an asymmetric slot structure is designed to increase the output electric power, and detailed analyses of the magnetic field distribution, detent force characteristics, and no-load and load performances conducted using finite element analysis are discussed. The TPMLG with an asymmetric slot, which produces the same power as the TPMLG with a symmetric slot, has one fifth detent force of the latter. An experiment system with a prototype of the TPMLG with a symmetric slot is used to test the simulation results. The experiment and analysis results agree well. Therefore, the proposed D-DWEC fulfills the requirements of WEC systems.

“…An extremely abundant and promising source of energy exists in oceans. Among these forms of ocean energy, signficant opportunities and benefits have been identified in the area of ocean wave energy extraction [1,2]. Since the 1970s, researchers from all over the world have studied wave energy conversion (WEC) systems that can harness the motion of ocean waves and convert it into electrical energy [3].…”

Section: Introductionmentioning

confidence: 99%

A Study on a Linear Magnetic-Geared Interior Permanent Magnet Generator for Direct-Drive Wave Energy Conversion

Feng

et al. 2016

Abstract:The conventional linear permanent magnet generator (CLPMG) for direct-drive wave energy conversion (WEC) has experienced many drawbacks that are difficult to overcome such as low power density and bulky system volume. To improve power density, this paper proposes a linear magnetic-geared interior permanent magnet generator (LMGIPMG) with tubular topology, which artfully incorporates a linear magnetic gear into a linear permanent magnet generator. The operating principle of the LMGIPMG is introduced, and a detailed analysis of air gap flux density, thrust force characteristics, and no-load and load performances are presented and discussed by using finite element method. The CLPMG, which produces the same power as the LMGIPMG, has about four times the volume of the latter. A prototype CLPMG is manufactured to verify simulation results against experimental tests. The design method and the operation conditions of LMGIPMG and CLPMG are both consistent; thus, the performance of LMGIPMG meets the operation requirements of the direct-drive WEC.