• 조명전기설비학회논문지
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• 제26권12호
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• pp.50-55
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• 2012

This paper presents an application of optimization method for efficient operation in micro grid. For operational efficiency, the objective function in a diesel generator consists of the fuel cost function similar to the cost functions used for the conventional fossil-fuel generating plants. The wind turbine generator is modeled by the characteristics of variable output. The cost function of fuel cell plant considers the efficiency of fuel cell. Particle swarm optimization(PSO) and sequential quadratic programming(SQP) are used for solving the problem of microgrid system operation. Also, from the results this paper presents the way to attend power markets which can buy and sell power from upper lever grids by connecting a various generation resources to micro grid.

• 한국전산유체공학회지
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• 제18권2호
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• pp.41-48
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• 2013

Ice accretion on the solid surface is an importance factor in assessing the performance of aircraft and wind turbine blade. Changes in the external shape due to ice accretion can greatly deteriorate the aerodynamic performance. In this study, a three-dimensional upwind-type second-order positivity-preserving finite volume CFD scheme based on the unstructured mesh topology is developed to simulate two-phase flow in atmospheric icing condition. The code is then validated by comparing with NASA IRT experimental data on the sphere. The present results of the collection efficiency are found to be in close agreement with experimental data and show improvement near the stagnation region.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.414-419
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• 2012

The evaluation of a zonal RANS-LES approach is documented for the prediction of broadband noise generated by the flow past unmodified and serrated airfoil trailing edges at a high Reynolds number. A multi-domain decomposition is considered, where the acoustic sources are resolved with a LES sub-domain embedded in the RANS domain. A stochastic vortex method is used to generate synthetic turbulent perturbations at the RANS-LES interface. The simulations are performed with a general-purpose unstructured control-volume code FLUENT. The far-field noise is calculated using the aeroacoustic analogy of Ffowcs Williams-Hawkings. The results of the simulation are validated through the full-scaled wind turbine acoustic measurements. It is found that the present approach is adequate for predicting noise radiation of serrated trailing edge flow for low noise rotor system.

• 한국소음진동공학회논문집
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• 제22권5호
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• pp.444-450
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• 2012

The evaluation of a zonal RANS-LES approach is documented for the prediction of broadband noise generated by the flow past unmodified and serrated airfoil trailing edges at a high Reynolds number. A multi-domain decomposition is considered, where the acoustic sources are resolved with a LES sub-domain embedded in the RANS domain. A stochastic vortex method is used to generate synthetic turbulent perturbations at the RANS-LES interface. The simulations are performed with a general-purpose unstructured control-volume code FLUENT. The far-field noise is calculated using the aeroacoustic analogy of Ffowcs Williams-Hawkings. The results of the simulation are validated through the full-scaled wind turbine acoustic measurements. It is found that the present approach is adequate for predicting noise radiation of serrated trailing edge flow for low noise rotor system.

• Transactions on Electrical and Electronic Materials
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• 제18권5호
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• pp.265-272
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• 2017

This paper presents the dynamic modeling, analysis, and control of an AC/DC/AC-assisted, self-excited induction generator connected to the grid. The dynamic model includes wind turbine models with pitch control, gear boxes, self-excited induction generators, excitation capacitance, inductive load models, controlled six-pulse rectifiers, and novel state-space models of a grid-connected inverter. The system has been simulated to verify its capabilities of buildup voltage, stator flux response, stator phase current, electromagnetic torque, and magnetizing inductance variation during both the dynamic and steady states with a variable-speed prime mover. The complete setup of the above dynamic models was simulated using MATLAB/SIMULINK.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.143-144
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• 2015

최근 대체에너지에 대한 관심이 많아진 가운데 풍력발전에 대한 관심이 증대하고 있다. 풍력발전기는 사람의 접근이 용이하지 않은 산간벽지에 주로 설치됨에 따라 상시 운전상태를 모니터링하기 위한 원격 모니터링 장치가 필요하다. 본 논문에서는 풍력발전기의 원격 모니터링 시스템을 개발에서 필요한 요소기술 분야의 설계 방법을 제시한다. 다수의 풍력발전기가 설치되는 풍력단지에서 효과적으로 모니터링을 위해 Zigbee 무선통신을 사용하여 모니터링하고, 모니터링 시스템 구현이 용이한 LabVIEW를 활용하여 실시간 상태 모니터링의 설계 요소를 제안한다.

• International Journal of Advanced Culture Technology
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• 제3권1호
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• pp.101-112
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• 2015

Renewable energy resources play an important part in the world's future. Renewable energy sources have the following components: biomass, geothermal, solar thermal, directs solar, wind, tidal and hydropower. Hydropower is still the most efficient way to generate electricity worldwide. Hydropower projects can contribute as a cheap energy source, as well to encourage the development of small industries across a wide range of new technology; furthermore hydropower systems use the energy in flowing and falling water to produce electricity or mechanical energy. Hydropower systems are classified as large, medium, small, mini and micro according to their installed power generation capacity, as do the following components: water turbines, control mechanisms and electrical transmissions. In this article a review of small hydropower systems has been done on the principles surrounding the fundamentals of hydraulic engineering, the fundamentals of hydrology, identification of sites and economic analysis.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.292-294
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• 2008

최근 환경 파괴와 에너지 고갈에 대한 문제들이 사회의 큰 문제로 대두 되면서 풍력발전의 중요성이 증가하고 있다. 본 논문에서는 LabVIEW를 이용하여 이더넷(Ethernet) 환경에서의 풍력발전 원격감시 제어시스템을 구현하였다. 제안된 원격감시 제어시스템은 풍력발전 시스템의 MCU와 W5100의 SPI(Serial Peripheral Interface)를 통한 이더넷 통신용 하드웨어를 구축하였으며, NI사의 LabVIEW를 이용하여 서버상의 HMI(Human Machine Interface) 소프트웨어를 구현하였다. 본 연구의 실험을 위해 영구자석형 동기 발전기(PMSG:Permanent Magnet Synchronous Generator)를 이용하여 풍력발전 시스템 모델을 구현하고 이를 이용하여 원격감시 제어시스템의 성능을 검증하였다.

• 한국안전학회지
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• 제11권2호
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• pp.42-51
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• 1996

Taper roller bearing is used on rotating shaft where radial and thrust loads are attended. To avoid the sudden failure and maintain the good condition of rotating machinery it is necessary to monitor the condition of bearing and diagnose the defect of bearing. In this study the diagnosis program of taper roller bearing which is used on the lower bearing of V.A.W.T. (Vertical Axis Wind Turbine) is developed. By plenty of test the database is constructed and by Gaussian distribution obtained from database the defect probability of bearing is calculated.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 전력전자학술대회 논문집
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• pp.472-473
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• 2014

본 논문에서는 직렬운전 소형풍력발전시스템의 해석 방법과 최대 파워를 추종하는 MPPT(Maximum Power Point Tracking)기법을 제안한다. 소형풍력 발전시스템은 개별 발전기에서 생성되는 역기전력이 낮아 배터리 충전과 같은 독립적인 부하에 전원을 공급하는 용도로 쓰이나 발전기를 N개 직렬연결하면 계통연계가 가능하다. 일반적인 풍력발전 시스템에서의 블레이드 출력은 출력 계수($C_p$) 곡선의 형태에 의해서 결정되고, 출력계수 곡선은 주속비(${\lambda}$)의 함수로 표현된다. N개의 발전기를 직렬연결 하는 경우 각기 다른 풍속에 대하여 출력파워 해석이 곤란하므로, 직렬 운전 시 발전기토크를 기준으로 한 해석과 이에 적합한 MPPT 방법을 제안한다.