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Design and Performance Evaluation of Hinge Type Pitch Control System in Small-Size Wind Turbine
성창민,한명철 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.3 No.4
The present study is about pitch control system of a small wind turbine using hinge mechanism. Small wind turbines generally apply stall control method or breaking equipment over the rated wind speed by reason of price or efficiency. However we perform pitch control applying the hinge mechanism which is simpler than that of medium and large size wind turbines. The hinge mechanism is a kind of linkage. It is composed of a rotation motion part, a linear motion part and a connection part. Pitch angle is controlled by the rotation parts which are connection to blades. In order to determine relationship between the hinge links and pitch angle, kinematic analysis is performed. Also, we derive design specifications of the actuator which drives the hinge mechanism by the Jacobian analysis. Simulation using MATLAB analyses forces and velocities of the hinge type pitch control system. Finally, as applying it to a 20 kW small wind turbine, the performances are evaluated by wind tunnel test.
이온 보조 증착에 의해 제작된 MgF₂ - TiO₂ 혼합 박막의 광학적, 구조적 특성 분석
성창민(Chang Min Sung),반승일(Seung Il Ban),김형근(Hyeong Geun Kim),김석원(Sok Won Kim),한성홍(Sung Hong Hahn) 한국광학회 1997 한국광학회지 Vol.8 No.5
MgF₂와 TiO₂를 각각 다른 두 증발원으로부터 동시에 증착시켜 혼합 박막을 제작하였다. 박막의 특성을 개선시키기 위해 이온 보조 증착(IAD)을 하였다. 제작된 MgF₂-TiO₂ 혼합 박막의 원소 조성비, 광학적 특성과 결정 구조를 분석하였다. 상대적 증착률을 달리하여 제작된 MgF₂-TiO₂ 혼합 박막의 Mg:Ti의 조성비는 비선형적으로 변화하였으며 MgF₂의 조성비를 상대적으로 증가시킴에 따라 혼합 박막의 굴절률은 감소하였고 Drude 모델을 잘 만족함을 알 수 있었다. 그리고 MgF₂의 조성비가 증가할수록 비정질인 TiO₂ 구조 사이에 다결정질인 MgF₂의 양이 증가하여 결정성을 갖는 박막으로 성장함을 확인하였다. The composite MgF₂-TiO₂ films are fabricated by codepositon from two independent sources. To improve optical and mechanical properties of films, the films are prepared by ion-assisted deposition. Chemical compositions, optical properties and microstructures of the composite films were investigated. The chemical composition rates of Ti:Mg of MgF₂-TiO₂ composite films are nonlinearly varied according to the relative deposition rate. It is found that the refractive indices of the composite films decrease with increasing MgF₂ contents and can be fitted quite well with Drude's formula and that the microstructures of the composite films changes from an amorphous to crystalline with increasing MgF₂ mole fractions.