• 한국산업정보학회논문지
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• 제18권2호
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• pp.13-18
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• 2013

The authors designed a high temperature superconductor (HTS) racetrack coil for a 10 MW class superconducting synchronous wind turbine generator. The designed HTS racetrack coil was analyzed by an electromagnetic finite element method (FEM) to determine the magnetic field distribution, inductance, stress, etc. This paper describes the stress analysis and structure design result of the HTS racetrack coil for 10 MW class superconducting synchronous wind turbine generators, considering orthotropic material properties, a large magnetic field, and the resulting Lorentz force effect. Insulated HTS racetrack coils and no-insulation HTS racetrack coils were also considered. According to the results of the stress analysis, the no-insulation HTS racetrack coil results were better than the insulated HTS racetrack coil results.

• 한국기계가공학회지
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• 제21권2호
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• pp.31-38
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• 2022

Recently, the development of offshore wind farms based on past technical experiences from onshore wind turbine installations has become a worldwide issue. This study investigated the technical issues related to offshore wind farms and large-diameter monopiles from an economic perspective. In particular, the monopile foundation system (MFS), which is the most important part of the proposed fast construction system, is applied for the first time in Korea, and structural verification is essential because it supports large-diameter monopiles and is in charge of excavation. Therefore, in this study, a rapid construction system for large offshore wind power generators was introduced, and stability verification was performed through the structural analysis of the MFS.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.459-460
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• 2011

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.804-805
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• 2009

• 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.

• 제어로봇시스템학회논문지
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• 제21권1호
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• pp.28-33
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• 2015

In this paper, we propose a near optimal controller design method for permanent magnet synchronous generators (PMSGs) of MW-class direct-driven wind turbine systems based on SDRE (State Dependent Riccati Equation) approach. Using the solution matrix of an SDRE, we parameterize the optimal controller gain. We present a simple algorithm to compute the near optimal controller gain. The proposed optimal controller can enable PMSGs to precisely track the reference speed determined by the MPPT algorithm. Finally, numerical simulation results are given to verify the effectiveness of the proposed optimal controller.

• 한국지열·수열에너지학회논문집
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• 제17권1호
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• pp.23-32
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• 2021

Conventional wind power generators have limited installation sites due to low efficiency due to reverse resistance or high cut-in speed. To compensate for these problems, this study proposed another new type of tilting wind turbine. The key to this method is the structural design of a cylindrical cam with a guide groove that allows the blade to tilt. As the blade rotates by the cam, it tilts according to the angle. In the section that generates torque by receiving drag, the blade is made perpendicular to the wind. And it is a structure that creates a parallel state with the wind in the section where reverse resistance occurs. We prepared six types of cams considering the length of the section subject to drag, reverse resistance, tilting section. The performance was analyzed as the maximum value of the output, torque coefficient, and efficiency coefficient, which is indicated by setting different wind speed and low TSR.

• 대한기계학회논문집B
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• 제36권5호
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• pp.465-475
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• 2012

본 연구는 두 가지 목표를 가지고 수행하였다. 하나는 수치해석과 Design-FOIL Pro.를 이용해 블레이드 에어포일 모델개발이고, 다른 하나는 이 모델을 Folding blade에 적용하는 것이다. 일반적으로 1MW이상 대형풍력터빈용 블레이드는 강풍시에 피칭제어로 풍향에 대해서 평형상태를 유지하여 로터를 회전시키지 않는 방법으로 블레이드의 손상을 방지 하였지만, 소형풍력터빈용 블레이드는 설비비, 유지비등 경제성을 이유로 피칭제어를 채택하지 않아 블레이드의 파손 문제가 심각하다. 그래서 본 연구에서는 유지보수가 필요 없고 강풍에서도 파손이 없는 Spring pack을 이용한 로터를 직접설계(Direct-Design) 방법으로 설계하여, 그 성능을 검증 하고 변화 풍속에 맞는 폴딩각을 이용해 강풍시에도 Wind turbine이 Cut-out 없이 계속발전을 유지할 수 있도록 하는 점에 집중 연구하고자 한다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.818-821
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• 2005

The sound measurement procedures of IEC 61400-11 are applied to field test and evaluation of noise emission from 1.5 MW wind turbine generator (WTG) at Yongdang and 660 kW WTG at Hangwon in Jeju Island. Apparent sound power level, wind speed dependence and third-octave band levels are evaluated for both of WTGs. 1.5 MW WTG at Yongdang is found to emit lower sound power than 660 kW one at Hangwon, which seems to be due to lower rotating speed of the rotor of WTG at Yongdang. Equivalent continuous sound pressure levels (ECSPL) of 660 kW WTG at Hangwon vary more widely with wind speed than those of 1.5 MW WTG at Yongdang. The reason for this is believed to be the fixed blade rotating speed of WTG at Yongdang. One-third octave band analysis of the measured data show that the band components around 400-500 Hz are dominant for 1.5 MW WTG at Yongdang and those around 1K Hz are dominant for 660 kW WTG at Hangwon.

• Journal of Electrical Engineering and Technology
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• 제11권4호
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• pp.801-809
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• 2016

The electrically excited synchronous generator (EESG) is applied in wind turbine systems recently. In an EESG control system, electrical torque is affected by stator flux and rotor current. So the control system is more complicated than that of the permanent-magnet synchronous generator (PMSG). Thus, the higher demanding of the control system is required especially in case of wind turbine mechanical resonance. In this paper, the mechanism of rotor speed resonant phenomenon is introduced from the viewpoint of mechanics firstly, and the characteristics of an effective damping torque are illustrated through system eigenvalues analysis. Considering the variables are tightly coupled, the four-order small signal equation for torque is derived considering stator and rotor control systems with regulators, and the bode plot of the closed loop transfer function is analyzed. According to the four-order mathematical equation, the stator flux, stator current, and electrical torque responses are derived by torque reference step and ramp in MATLAB from a pure mathematical deduction, which is identical with the responses in PSCAD/EMTDC simulation results. At last, the simulation studies are carried out in PSCAD software package to verify the resonant damping control strategy used in the EESG wind turbine system.