• 한국기계가공학회지
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• 제17권1호
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• pp.122-129
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• 2018

This study conducted a seismic qualification analysis of small savonius style vertical axis wind turbine(VAWT) using finite element method(FEM). The modal analysis was performed on the wind turbine structure to check the occurrence of resonance caused by the rotation of gearbox and windmill blades. Next, it conducted a seismic response spectrum analysis due to horizontal and vertical seismic load of required response spectrum of safe shutdown earthquake with 5 % damping(RRS/SSE 5%) of KS C IEC 61400 and conducted a static analysis due to deadweight and wind load. The total maximum stress of the VAWT structure was calculated by adding the maximum stresses due to each load case using the square root of the sum of the squares(SRSS) method. Finally, the structural safety of the VAWT structure was verified by comparing the total maximum stress and the allowable stress.

• 전력전자학회논문지
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• 제21권6호
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• pp.497-505
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• 2016

Operating wind turbine generators at maximum power point requires maximum power point tracking (MPPT) control methods. However, conventional methods cannot track the appropriate maximum power point in situations involving wind turbine systems based on a series operation strategy. These systems comprise one or more local maximum power points, and conventional methods can detect only one local maximum power point closed by a current operation point. This study proposes an advanced MPPT method for the series operation strategy of a small, grid-connected wind turbine system. In determining the appropriate maximum point, operations at certain local maximum power points are analyzed. The results show one appropriate point, which is tracked by the proposed MPPT method. The effectiveness of the proposed method is verified by the experimental results.

• 한국태양에너지학회 논문집
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• 제23권2호
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• pp.21-34
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• 2003

This study aims to present the applicability of wind turbine generator system to urban buildings for the utilization of clean renewable energy. The results are as follows; According to the wind resource analysis, it has been found that small sized wind power system can be viable for buildings application due to the amplification of wind velocity around buildings or building clusters, in spite of low mean velocity of 2-3m/s in Seoul and Kyunggi urban areas. But planners must perform micrositing analysis around building so that wind turbine can be located at high velocity zones. The system must be designed to avoid obstacles preventing prevailing wind in buildings. It should be recognized that wind speeds are changing depending on the height and length from buildings. The wind power system can be used as a symbol of landmark which shows a sustainable architecture from the scenary Itself A case study for apartment building in urban showed that wind power systems can be applicable in two kinds of place, rooftops and ground levels. Especially, the wind power systems must be carefully positioned so that wind resources do not decrease when it is installed at ground levels. and according to life cycle cost analysis, adaption of new small win4 power systems to buildings were proved to produce a profit if it is considered the expense of environment improvement and the wind speed increasing according to rise of building height. This research will ultimately achieve green architecture that preserves nature and at the same time provides pleasant environment to humans, and will play a great role in establishing the environment-preserving sustainable architecture of the 21th century.

• 한국신뢰성학회지:신뢰성응용연구
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• 제17권3호
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• pp.236-245
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• 2017

Purpose: There is no established inspection system for composite wind blade during the fabrication stage even though the blades are one of the most important part at wind generation system, but phased array ultrasonic testing method has been continuously studied about wind turbine blade with composite. When wind turbine blade with complex shape by phased array probe is inspected, it is necessary to study for system keeping constant pressure using pressure device. Methods: In this paper, we propose constant pressure device for inspecting wind turbine blade by phased array ultrasonic test method. Design of the device controller is based on Hunt-Crossley model. We evaluate reliability of phased array ultrasonic inspection result that applicated constant pressure device. Result: Defect indication is precise and its error is small when constant pressure mechanism based on Hunt-Crossley model was used. Conclusion: When inspection is progressed using constant pressure mechanism, the reliability of composite wind blade inspection can be improved.

• 한국유체기계학회 논문집
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• 제15권3호
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• pp.5-11
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• 2012

This study is to develop a 1kW-class horizontal axis wind turbine(HAWT) rotor blade which will be applicable to relatively low wind speed regions in southwest islands in Korea. Shape design of 1kW-class small wind turbine rotor blade is carried out using a blade profile with relatively high lift to drag ratio by blade element momentum theory(BEMT). Aerodynamic analysis on the newly designed rotor blade is performed with the variation of tip speed ratio. Power coefficient and pressure coefficient of the designed rotor blade are investigated according to tip speed ratio.

• 한국기계가공학회지
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• 제15권3호
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• pp.21-27
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• 2016

The static and dynamic structural integrity qualification was performed through the seismic analysis of a small-size Savonius-type vertical wind turbine at dead weight plus wind load and seismic loads. The ANSYS finite element program was used to develop the FEM model of the wind turbine and to accomplish static, modal, and dynamic frequency response analyses. The stress of the wind turbine structure for each wind load and dead weight was calculated and combined by taking the square root of the sum of the squares (SRSS) to obtain static stresses. Seismic response spectrum analysis was also carried out in the horizontal (X and Y) and vertical (Z) directions to determine the response stress distribution for the required response spectrum (RRS) at safe-shutdown earthquake with a 5% damping (SSE-5%) condition. The stress resulting from the seismic analysis in each of the three directions was combined with the SRSS to yield dynamic stresses. These static and dynamic stresses were summed by using the same SRSS. Finally, this total stress was compared with the allowable stress design, which was calculated based on the requirements of the KBC 2009, KS C IEC 61400-1, and KS C IEC 61400-2 codes.

• 한국가시화정보학회지
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• 제11권1호
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• pp.28-33
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• 2013

This paper describes aerodynamic characteristics of an Archimedes spiral wind turbine with various angles of attack. The range of angles was controlled from $-30^{\circ}$ (clockwise) to $+30^{\circ}$ (clockwise). The rotating speed of wind turbine at the same angle of attack in both directions was different. The reason why the-maximum rotational speed was observed at $15^{\circ}$ in clockwise direction can be explained based on angular momentum conservation. Quantitative flow visualization around Archimedes wind turbine blade was carried out between $-15^{\circ}$ (clockwise) and $+15^{\circ}$ (counter clockwise) using high resolution PIV method. The relationship between drag force and rotating speeds was discussed. From these results, optimum design on yawing system of Archimedes spiral wind turbine may provide high efficiency on small wind power system.

• 한국태양에너지학회 논문집
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• 제32권4호
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• pp.1-8
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• 2012

A Fiber Bragg Grating (FBG) sensor imbedded small wind turbine blade was manufactured to experimentally investigate the feasibility to embed FBG sensors between layers of glass fiber to monitor dynamic strains of the wind turbine blade. The blade which is similar to a commercial 300 W wind turbine blade was manufactured with glass fiber as a reinforcement and epoxy resin as base material. A total of five FBG sensors including one temperature sensor were imbedded in the blade to sense mechanical strain and temperature. While manufacturing the blade, residual strain and temperature that occurred in the small wind turbine blade were monitored using the imbedded FBG sensor array. To examine the sensor performance, an impact test was carried out. The experimental results from the FBG sensors were close to those from electrical strain gages mounted on the blade root surface. The mode shapes of the blade were analyzed also using a commercial Ansys simulation with a model obtained from a three dimensional laser scanning of the blade.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.191.2-191.2
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• 2005

• 한국정보기술학회논문지
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• 제15권12호
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• pp.181-188
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• 2017

레저 활동 인구의 증가와 다양화로 이동용 전력 시스템에 대한 수요가 많고 친환경적인 전력 발전 시스템에 대한 요구가 늘어나고 있으며 이를 충족 시킬만한 발전 장비로 소형 풍력 발전시스템이 대안으로 떠오르고 있다. 이동용 소형 풍력발전기를 개발할 때 가장 중요한 사항으로는 발전기의 무게를 줄이고 효율을 증가시키는 것이다. 기존의 300W급 풍력 발전기의 무게는 10kg정도로 이를 4kg이하로 줄여서 휴대가 용이하게 하면서 고 효율의 풍력 발전기용 발전기를 설계 제작하였다. 또한, 돌풍이 발생하는 한국의 풍량과 지형의 특성상 미풍에서도 발전이 가능하고 도심 및 농어촌 등에서도 독립적으로 사용할 수 있는 소형 풍력발전기를 설계 제작하였다. 기초설계 및 최적화설계를 통해 가볍고 효율이 높은 발전기를 제작하였다. 본 논문에서는 중량을 줄인 300W급 풍력발전기를 설계하고 시제품으로 제작 하였다. 제작한 300W 풍력발전기는 무부하 시험 시 정격속도 900rpm에서 평균출력전압이 24.7V이었으며, 제작된 발전기의 부하시험시 평균 선간전압 : 36.8V, 평균 상전류 : 2.62A로 기계적 입력이 339.84W일 때 출력전력은 289.5W로 측정되었고 이때의 효율은 85.18%이었다. 제작된 발전기 무게는 3.84kg이었다.