• Journal of the Korean Solar Energy Society
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• v.30 no.5
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• pp.63-68
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• 2010

To guarantee life time more than 20 years for manufacturer without stopping photovoltaic(PV) system, it is really important to test the module in realistic time and condition compared to outside weather. In here, we tested PV modules in highly stressed condition compared to IEC standards. In IEC 61215 and IEC 61646 standards, damp-heat, thermal cycle(TC200) and mechanical test are main test items for evaluating long-term durability of PV module in controlled temperature and humidity condition. So in this paper, we have lengthened the test time for TC200 and damp-heat test and increased the loading stress on surface of module. Through this test, we can get some clue of proper the method for measuring realistic life cycle of PV modules and suggested the minimum time for PV test method. The detail description is specified as the following paper.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.600-605
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• 2009

A general purpose viscous flow solver Ansys CFX is used to study a Savonius type wave energy converter in a 3D numerical viscous wave tank. This paper presents the results of a computational fluid dynamics (CFD) analysis of the effect of blade configuration on the performance of 3 bladed Savonius rotors for wave energy extraction. A piston-type wave generator was incorporated in the computational domain to generate the desired incident waves. A complete OWC system with a 3-bladed Savonius rotor was modeled in a three dimensional numerical wave tank and the hydrodynamic conversion efficiency was estimated. The flow over the rotors is assumed to be two-dimensional (2D), viscous, turbulent and unsteady. The CFX code is used with a solver of the coupled conservation equations of mass, momentum and energy, with an implicit time scheme and with the adoption of the hexahedral mesh and the moving mesh techniques in areas of moving surfaces. Turbulence is modeled with the k.e model. Simulations were carried out simultaneously for the rotor angle and the helical twist. The results indicate that the developed models are suitable to analyze the water flows both in the chamber and in the turbine. For the turbine, the numerical results of torque were compared for all the cases.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.341-344
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• 2009

In this paper, protective function evaluation was conducted to determine the performance and safety of a power conditioning system(PCS) for 1kW residential fuel cell system. It is essential to have a power quality, grid-connection and safety of PCS. Even though it is under 500ms by KGS-A410 standard, it is shown a rapid response time of 25ms from input under-voltage test. In terms of output over/under-voltage test, it is shown 29.15 and 79.4ms. Especially using anti-islanding test, it is shown all times under 100ms for combination cases of real and reactive power. We confirmed a rapid response characteristics and safety of PCS. The results of this evaluation are being used to develop a new test protocols of PCS.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.236.2-236.2
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• 2010

The tidal current power is the power plant by installing the turbine or rotor where the tidal speed is fast. This system converting the horizontal movement to rotating energy. Tidal power turbine is needed for the dam to utilize the pressure difference. However, tidal current power using the only flow. The tidal current power was evaluated as the impact on the marine environment surrounding was less and the development of eco-friendly way. In this article, we calculated the effect of tidal current turbine on the tidal power generating by mean of CFD. With these calculated results, we checked the possibility of tidal current power using tidal power plant the discharge gate.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.179.2-179.2
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• 2010

This research has been performed to provide fundamental design aspects of Permanent Magnet Synchronous Generators(PMSGs) for a kilowatt class wind turbine. When it comes to kilowatt class wind turbines, the typical type of generators are Axial Flux Permanent Magnet(AFPM) generators. However, Radial Flux Permanent Magnet(RFPM) generators have been optimally designed to study the output characteristics of a kilowatt class wind turbine in Graduate School of Wind Energy, POSTECH. An existing squirrel-cage rotor has been modified for another newly designed permanent magnet rotor to utilize the commercially existing stator rotor. Electromagnetic analysis utilizing Finite Element Methods tools(ANSYS, MAXWELL 2D) has been applied to analyze the system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.139-139
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• 2009

As ideal new energy, solar cell has renewable and inexhaustible characteristics and the fuel cell only needs low maintenance and low operating cost. This paper introduces hybrid system of solar cell and fuel cell considering the advantages of stable and sustainable energy from the economic point of view. Then the paper shows the I-V characteristics of the solar module which are dependent on the power of the halogen lamp and the P-I and I-V characteristics of fuel cells which are connected in parallel and series.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.412-415
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• 2005

Solar thermal power generation is one of promising and well-proven ways to convert solar energy to electricity. Though it requires high initial cost for system construction and continuous efforts for maintainment. it is more positive in terms of efficiency than other solar power generation technologies. Moreover, solar thermal power generation allows additional benefits of cheap thermal storage and easy hybridization with other fossil fuel-driven power generation. Owing to these benefits, large scale solar thermal power generation technology is expected to be competitive to other commercial technologies in the near future. In this paper an overview on the solar thermal hybrid power generation technology and the state of the art in Korea were briefly introduced.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.333-336
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• 2008

3MW 풍력발전기용 발전기의 구조적 특성을 소개하고 회전자의 동특성 해석을 수행하였다. 이 발전기는 증속기를 사용하였으며 정격속도는 1459 rpm 이며 30% over speed trip 조건을 적용하여 설계되었다. 회전자 pole에 전원 공급 없이 자기장을 만드는 영구자석을 사용하는 형태로 구조는 간단하다. 발전기의 냉각방법은 공극을 냉각하기 위하여 팬을 이용하여 공기를 순환하며 고정자 외형에는 냉각채널을 부착하여 냉각수를 순환한다. 회전기계의 설계 시에는 반드시 진동을 고려하여 가능하면 진동을 줄이는 방향으로 설계가 되어야 하며 회전축 계의 설계에 있어서는 계의 강도, 위험속도, 불평형 진동응답 및 안정성 등을 고려하여야 한다. 본 논문에서는 물리설계를 기본으로 하여 설계된 발전기의 형상을 간단하게 설명하고, 발전기의 회전자를 상용 유한요소 해석 프로그램인 ANSYS 를 이용하여 해석을 수행하였다. 해석절차는 정적해석을 수행하고 다음으로 모드해석을 수행 하였다. 모드형상에 따른 주파수를 표기하고 해석 결과를 나타내었다.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.190-193
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• 2008

The heat transfer characteristics of molten salt storage system for the solar thermal power generation were investigated. Temperature profiles and the heat transfer coefficients during the storage and discharge stage were obtained with the steam as the heat transfer fluid. Two kinds of inorganic salt were employed as the storage materials and coil type of heat exchanger were installed in both tanks to provide the heat transfer surfaces during the storage and discharge stage. The effects of steam flow rates, flow direction of steam in the storage tank and the initial temperature of storage and discharge tank on the heat transfer were tested.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.547-555
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• 2007

In order to transmit energy generated through the stator winding of a doubly-fed induction generator (DFIG), we need to synchronize the generated voltage vector with the grid voltage vector. However, the existing synchronization methods work only when the encoder is installed at a specific position and equivalent constant is precise. In order to solve this problem, a new synchronization method has been proposed and a way of applying the method to existing doubly-fed induction generator control algorithm has been also proposed. The validities of the methods proposed were verified by using a prototype converter for a 1.5MW-class doubly-fed induction generator and experimental results showed the validity of that against variation of an encoder positions, generator parameters, and grid voltages.