• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.3
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• pp.194-202
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• 2016

This study aims to review a topology optimization based on finite element analysis (FEA) for conceptual design of platform in the 10MW class floating type wave-wind hybrid power generation system (WHPGS). Two topology optimization theories, density method (DM) and homogenization design method (HDM) were used to check which one is more effective for a simplified structural design problem prior to the topology optimization of platform of WHPGS. From the results of the simplified design problem, the HDM was applied to the topology optimization of platform of WHPGS. For the conceptual platform design of WHPGS, FEA model was created and then the structural analysis was performed considering offshore environmental loads at installation site. Hydrodynamics analysis was carried out to calculate pressure on platform and tension forces in mooring lines induced from the offshore environmental loads such as design wave and current. Loading conditions for the structural analysis included the analysis results from the hydrodynamic analysis and the weights of WHPGS. Boundary condition was realized using inertia relief method. The topology optimization of WHPGS platform was performed using the HDM, and then the conceptual arrangement of main structural members was suggested. From the results, it was confirmed that the topology optimization might be a useful tool to design the conceptual arrangement of main structural members for a newly developed offshore structure such as the floating type WHPGS.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.3
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• pp.99-106
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• 2011

50kW급 동체회전형 파력발전시스템(WEC;wave energy converter)의 전력변환장치(PTO; power take-off)를 설계 제작한 후 성능시험을 하였다. 파력발전시스템은 2개의 실린더형 동체가 회전관절로 연결된 구조로 수면의 반정도 잠기는 구조로 되어있다. 파랑에 의해 유도된 회전관전의 움직임이 유압실린더에 힘을 가해주며, 유압실린더는 고압의 작동유를 축압기를 경유하여 발전기에 체결된 유압모터로 공급한다. 유압식 PTO은 유압실린더가 왕복운동하는 움직임을 이용하여 고품질의 전력을 생산하는데 효과전인 수단을 제공한다. 파력발전시스템의 경제성은 PTO의 에너지 변환 효율에 크게 의존한다. 발전기를 AC 380V 전력계통에 연계시킨 후, 발전기에서 나오는 출력이 5, 20, 35, 43kW 일때 PTO 전체와 개별기기에 대한 효율을 측정하였다. 본 논문에서 유압식 PTO시스템의 설계에 대해 설명하였으며 효율 향상에 초점을 맞추어 PTO 성능대해 분석하였다.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.8
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• pp.1028-1034
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• 2011

This paper have been studied that ocean wave power vibration generation system with two D.O.F.(degree of freedom) consists of buoy and vibration generation system with two D.O.F. for using efficiency of ocean wave energy. It selected main frequencies ${\omega}_1$, ${\omega}_2$ in frequency with ocean wave and it fitted them to the natural frequencies of vibration system with two D.O.F. in the vibrational power generation system. Then each the relative velocity of between the winding coil and the permanent magnet is faster than the velocity of ocean wave up and down motion by resonance phenomenon. Also the ocean wave power generation with two D.O.F. obtained the more electric energy then the ocean wave power generation with one D.O.F. by coupling effect for two D.O.F. vibration system. Therefore ocean wave power vibration generation system with two degree of freedom that is proposed in this paper has merits which not only using more energy in the ocean wave but also obtaining more electronic energy.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.35-36
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• 2017

본 논문은 파력발전 장치의 최대 전력 운전을 위한 가변 부하 시스템을 구현하고 해상 및 육상 실험을 통해 검증하였다. 파력 장치는 가변 스프링, 댐퍼, 질량, 동기발전기, 가변 부하 시스템 등으로 구성되었으며, 동기발전기는 최대 출력을 발생시킨다. 파도 조건에 따라 달라지는 부하의 크기는 최적부하계산 알고리즘을 통해 선정되었으며, 제안된 부하 시스템을 통해 부하의 크기를 가변시켰다. 파력발전 장치는 수조 장치를 통해 파도 진폭의 크기(200mm~600mm)와 주파수(0.2Hz~1Hz)를 가변시켜 발전된 전력을 비교 분석하였으며, 해상 시험을 통해 시스템의 성능을 검증하였다.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1054-1055
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• 2015

진동 수주형 파력발전 시스템(oscillating water column wave energy converter)의 효율을 증대할 수 있는 터빈의 최대 효율 추종 제어기를 제안한다. 진동 수주형 파력발전 시스템은 캡처 챔버(capture chamber)와 터빈, 발전기로 구성되어 있으며 발전기 말단에 연결된 저항의 값을 제어 입력으로 삼는다. 본 논문에서는 파력발전 시스템의 캡처 챔버와 터빈의 동역학 모델에 대해 소개하고, 터빈의 최대 효율 추종 제어기의 안정성을 증명하고 이를 JONSWAP 모델의 비규칙 파랑 조건하에서 시뮬레이션 하여 제어기 성능을 입증한다.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.115-116
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• 2015

본 논문에서는 PSCAD/EMTDC 소프트웨어를 이용하여 3MVA 용량의 풍력발전기와 2.4MVA 용량의 파력발전기로 구성되어 있는 부유식 파력-해상풍력 연계형 발전시스템 모델을 모의 할 예정이다. 각각의 발전시스템은 발전기, 발전기 컨버터, 전력망 컨버터, 전력망으로 구성되어 있고 시뮬레이션 결과를 통해 각각의 풍력 및 파력발전기에서 전력망의 유효전력과 무효전력을 완전히 독립적으로 제어 할 수 있음에 대하여 살펴 볼 것이다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.3
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• pp.223-232
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• 2015

The present paper considers the conceptual design of floating wave-offshore wind hybrid power generation system. The worldwide demand for ocean renewable energy is increasing rapidly. Wave and offshore wind energy have been attractive among the various ocean renewable energy sources, and the site to generate electricity from wave and offshore wind accords well together. This means that a hybrid power generation system, which uses wave and offshore wind energy simultaneously has many advantages and several systems have been already developed in Western Europe. A R&D project for a 10 MW class floating wave-offshore wind hybrid power generation system has been also launched in Korea. A semi-submersible platform, which has four vertical columns at each corner of the platform to be connected with horizontal pontoons, was designed for this system considering arrangements of multiple wind turbines and wave energy converters. A mooring system and power cable were also designed based on the metocean data of installation site. In the present paper, those results are presented, and the difficulties and design method in the design of hybrid power generation system are presented.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.2
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• pp.120-128
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• 2016

This paper describes power generation from sea waves by using linear permanent magnet generator. A buoy is placed on the ocean surface and connected to the generator. The wave energy is carried out from the movement of a buoy. An electrical conversion system is needed between the generator and the grid. For an analysis of the power system, the modeling of the linear generator and converter system was proceeded. This paper proposes vector control method for wave power generation system using linear generator. In order to verify the proposed method, simulation and experiment performed and the results support the validity of the control scheme.

• Journal of Navigation and Port Research
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• v.37 no.6
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• pp.597-601
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• 2013

Recently, many studies about the wave power generation system for the marine structure as the hybrid form in linked with the original features have been made of. Of these, the wave power generation system using oscillating water column(OWC) has function to convert wave energy to electrical energy with original function of the break water structure. In this type of generation system, it is important to make the flow of sea water as much as possible without loss. Output characteristics of wave power generation system depending on entrance section were described in the paper. Also, flow quantity changing with entrance section, velocity of sea water and output of wells turbine were measured by simulating OWC wells turbine model in break water, one of the general marine structure. Finally, entrance section was suggested to enhance the energy conversion efficiency based on the results of simulation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.2
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• pp.257-263
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• 2013

In this study, dynamic behaviors of a wave energy generation system (WEGS) that converts wave energy into electric energy are analyzed using multibody dynamics techniques. Many studies have focused on reducing the effects of a mooring system on the motion of a WEGS. Several kinematic constraints and force elements are employed in the modeling stage. Three-dimensional wave load equations are used to implement wave loads. The dynamic behaviors of a WEGS are analyzed under several wave conditions by using MSC/ADAMS, and the rotating speed of the generating shaft is investigated for predicting the electricity capacity. The dynamic behaviors of a WEGS with a mooring system are compared with those of a WEGS without a mooring system. Stability evaluation of a WEGS is carried out through simulation under extreme wave load.