• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2581-2583
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• 1999

The PV-Wind hybrid system was installed in the island where the solar and wind energy was compensated each other. The installed hybrid system, 10kWp-PV and 10kW-wind capacity, was monitored with the varying solar intensity and wind speed, under the minimum capacity of the storage battery.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.10
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• pp.1103-1109
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• 2013

This paper presents an optimal capacity design of a Hybrid generation system based on economical evaluation for various loads. Optimal sizes of a standalone and grid connection wind- PV hybrid systems were designed for normal, residential and industrial loads using HOMER (Hybrid Optimization Model for Electronic Renewable). Their economical evaluation were performed and compared with a diesel generation system that covers the same loads. The results showed that the stand alone hybrid generation system can be more economical than a diesel generation system for long term operation.

• Journal of Aerospace System Engineering
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• v.6 no.4
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• pp.7-11
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• 2012

Recently, the renewable energy has been widely used as a wind energy and solar energy resource due to lack and environmental issues of the mostly used fossil fuel. In this situation, the interest in wind power has been risen as an important energy source. For this blade a high efficiency wind turbine blade was designed with the proposing aerodynamic design procedure, and a light and low cost composite structure blade was designed considering fatigue life. Structural analyses including load case study, stress, deformation, buckling, fatigue life and vibration analysis were performed using the Finite Element Method.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1070-1071
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• 2015

전국에 분포하고 있는 분산형 전원설비의 구성요소와 발전소에 대한 정보를 축적하여 개인 사업자 및 공급자가 해당 정보를 쉽게 접근할 수 있도록 웹기반의 통합관리시스템을 구축하였다. 대표적인 분산형 전원설비인 태양광 발전소와 풍력 발전소의 구성요소 사양들과 전국 발전소의 설치 및 발전용량들에 대한 데이터를 축적하여 데이터베이스화하였다. 축적된 데이터베이스는 웹기반의 통합관리시스템으로 구축되어 사용자가 쉽게 정보를 검색하여 문제를 해결할 수 있도록 하였다. 또한 각 발전소의 실시간 모니터링을 통한 데이터는 통계기법을 통하여 수익성을 평가할 수 있는 기초 자료로 활용 가능하도록 하였다. 향후 비즈니스 모델을 활용하여 통합관리시스템의 지속적인 운영이 가능하도록 한다.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.39-41
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• 2018

독립형 인버터의 경우 상용 AC 계통(Utility Grid)이 없는 지역에서, 출력으로 단상 AC 전압(220Vrms / 60Hz)을 발생하는 전력 시스템이며 휘발유 연소 에너지, 풍력 에너지, 태양광 에너지 등 다양한 형태의 에너지를 전기 에너지로 변환하여 시스템의 입력으로 사용한다. 계통 연계 형 인버터의 경우 상용 AC 계통에 직접 연결하여, 발전된 전력을 계통에 주입(Inject)하는 전력 시스템을 말하며 출력으로 계통 전압과 동기화(Synchronization)된 단상 AC 전류를 발생시킨다. 기존 독립형 인버터의 출력에 계통 전원을 연결하면 작동이 불가능하고, 반대로 기존 연계형 인버터의 출력을 계통 전원 없이 동작하려고 하는 경우 또한 작동이 불가능하다. 본 논문에서는 상기 기존 기술의 한계를 극복할 수 있는 독립형 / 계통연계 호환형 단상 인버터를 제안하고 실제 구현을 통해 작동을 검증하였다.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.2
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• pp.109-116
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• 2001

The paper presents a speed control algorithm for a full pitch-controlled wind turbine system. Torque of a blade generated by wind energy is a nonlinear function of wind speed, angular velocity, and pitch angle of the blade. The design of the controller, in general, is performed by linearizing the torque in the vicinity of the operating point assuming the angular velocity of the blade is constant. For speed control, however the angular velocity is on longer a constant, so that linearization of the torque in terms of wind speed and pitch angle is impossible. In this study, a reference pitch model is derived in terms of a wind speed, angular velocity, and pitch angle, which makes it possible to design a controller without linearizing the nonlinear torque model of the blade. This paper also suggests a method of designing a hydraulic control system for changing the pitch angle of the blade.

• Journal of the Korean GEO-environmental Society
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• v.15 no.9
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• pp.47-58
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• 2014

This study explores methods for modeling the foundation-seabed interaction needed for the load analysis of an offshore wind energy system. It comprises the comparison study of foundation design load analyses for NREL 5 MW turbine according to various soil-foundation interaction models by conducting the load analysis with GH-Bladed, analysis software for offshore wind energy systems. Furthermore, the results of the aforementioned load analysis were applied to foundation analysis software called L-Pile to conduct a safety review of the foundation cross-section design. Differences in the cross-section of a monopile foundation were observed based on the results of the fixed model, winkler spring and coupled spring models, and the analysis of design load cases, including DLC 1.3, DLC 6.1a, and DLC 6.2a. Consequently, under all design load conditions, the diameter and thickness of the monopile foundation cross-section were found to be 7 m and 80 mm, respectively, using the fixed and coupled spring models; the results of the analysis conducted using the winkler spring model showed that the diameter and thickness of the monopile foundation cross-section were 5 m and 60 mm, respectively. The study found that the soil-foundation interaction modeling method had a significant impact on the load analysis results, which determined the cross-section of a foundation. Based on this study, it is anticipated that designing an offshore wind energy system foundation taking the above impact into account would reduce the possibility of a conservative or unconservative design of the foundation.

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.2
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• pp.15-23
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• 2019

High temperature superconducting (HTS) generators for wind power systems are attractively researched with the advantages of high efficiency and smaller size compared with conventional generator. However, the HTS generators have high Lorentz force problem, which acts on HTS field coils due to their high current density and magnetic field. This paper deals with characteristic analysis of the modularized HTS field coil for a 750 kW superconducting wind power generator according to field coil structure. The modularized HTS field coil structure was designed based on the electromagnetic and mechanical analysis results obtained using a 3D finite element method. The electromagnetic force of the module coil was also analyzed. As a result, the perpendicular and maximum magnetic fields of the HTS coils were 2.5 T and 3.9 T, respectively. The maximum stress of the supports was less than the allowable stress of the glass-fiber reinforced plastic material, and displacement was within the acceptable range. The design specifications and the results of the HTS module coil structure can be effectively utilized to develop large-scale superconducting wind power generators.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5893-5898
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• 2014

This paper proposes a modeling method and operating algorithm of an islanding microgrid that is composed of a Battery Energy Storage System (BESS), wind turbine and diesel generator applied in island areas. Initially, the bilateral AC/DC converter was designed for charge/discharge for frequency and voltage to be maintained within the proper ranges according to the load and weather change, and the operating method was proposed for a diesel generator to operate when power supply from the wind turbine or BESS is insufficient. The proposed modeling and controller design method of BESS was applied to a typical islanded microgrid with a wind turbine and diesel generator. The frequency and voltage was kept within the permissible ranges and the proposed method was proven to be appropriate through simulations.

• Journal of the Korean Solar Energy Society
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• v.32 no.5
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• pp.1-10
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• 2012

This paper proposes a modeling and controller design approach for a wind-diesel hybrid system including dump load. Wind turbine depends on nature such as wind speed. It causes power fluctuations of wind turbine. Excessive power fluctuation at stand-alone power grid is even worse than large-scale power grid. The proposed control scheme for power quality is fuzzy PI controller. This controller has advantages of PI and fuzzy controller. The proposed model is carried out by using Matlab/Simulink simulation program. In the simulation study, the proposed controller is compared with a conventional PI controller. Simulation results show that the proposed controller is more effective against disturbances caused by wind speed and load variation than the PI controller, and thus it contributes to a better quality wind-diesel hybrid power system.