• 조명전기설비학회논문지
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• 제24권9호
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• pp.8-15
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• 2010

This paper analyzes the steady-state output characteristics of variable-speed wind turbine systems using doubly-fed induction generators(DFIG) compared with fixed-speed induction generator(FSIG) wind turbine systems. It also presents simulations of a grid-connected wind turbine generation system for dynamics analysis on MATLAB/Simulink and compares the responses between DFIG and FSIG wind turbine systems with respect to wind speed variation, impedance changes and X/R ratio changes of interconnecting circuits. Simulation results show the variation of generator's active output, terminal voltage and fault currents at the interconnecting point. Case studies demonstrate that DFIG wind turbine systems illustrate better performance to 3-phase fault than FSIG's.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.97-100
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• 2003

Recently, the generators for wind turbine have been manufactured with high output power such like MW class machine in order to reduce the generation cost and to increase the energy efficiency. At the same time, direct-driven generators for wind turbine have been developed and researched, which have easy maintenance and high efficiency by simplification the system through the removal of the gear box. In this paper, at first, the advantage and disadvantage between the direct-driven generator system and conventional indirect-driven system are compared. And secondly, the permanent magnet generator (PMG) for wind turbine has been rapidly improved to cope with the recent trend which requires the high power output Per one machine and the convenience for maintenance, and the PMG is adequate for direct driven system and suitable for high-efficiency and light weight. So, the characteristics and technical trend of the PMG for wind turbine is examined. At last, a suitable technical trend for development of the permanent magnet generator for wind turbine is proposed.

• 산업기술연구
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• 제24권B호
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• pp.83-87
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• 2004

A reduced structure model of a wind turbine generator is designed and manufactured. Mode data are obtained by modal testing and analytical method. Vibration response is measured and investigated under various speed condition by using a waterfall plot. Possibility of severe resonance is observed and the mechanism is explained by using the mode data. Simplified theoretical model gives the 1st resonance frequency of wind turbine structure model. The theoretical model can be applied in the design stage of the wind turbine structure to avoid the severe resonance problem.

• 한국산학기술학회논문지
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• 제15권9호
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• pp.5893-5898
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• 2014

본 논문은 연료비를 최소화 할 수 있는 2차전지 전력저장장치(BESS: Battery Energy Storage System)와 풍력-디젤 복합발전시스템으로 구성되는 독립형 마이크로그리드을 모델링하는 방법과 그 운전제어 알고리즘을 제안하였다. 먼저, 부하변동 및 풍속변동에 따른 주파수와 전압을 일정하게 제어할 수 있는 양방향 DC/AC 컨버터의 BESS를 모델링하고, 디젤발전기는 공급전력의 부족 및 BESS의 충전시에만 가동하도록 하는 운전제어알고리즘을 제안한다. 그리고, 제안된 모델링 방법과 운전제어알고리즘을 독립형 마이크로그리드에 적용한 결과, 풍속 및 부하변화에 대하여 주파수와 전압변동이 적정범위내로 유지할 수 있음을 증명할 수 있었다.

• Journal of Electrical Engineering and Technology
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• 제7권6호
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• pp.869-875
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• 2012

Because of the nature of wind, the output power of wind turbines fluctuates according to wind speed variation. Therefore, many countries have set up wind-turbine interconnection standards usually named as Grid-Code to regulate the output power of wind farms to improve power system reliability and power quality. This paper proposes three operation modes of wind farms such as maximum power point tracking (MPPT) mode, single wind turbine control mode and wind farm control mode to control the output power of wind turbines as well as overall wind farms. This paper also proposes an operation scheme of wind farm to alleviate power fluctuation of wind farm by choosing the appropriate control mode and coordinating multiple wind turbines in consideration of grid conditions. The performance of the proposed scheme is verified via simulation studies in PSCAD/EMTDC with doubly-fed induction generator (DFIG) based wind turbine models.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1294-1295
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• 2011

This paper describes a conceptual design of 10 MW class gearless type superconducting synchronous generator for wind turbine. The main benefits of gearless type generator are decrease of the process of maintenance and loss caused by drive-train. The designed generator improves efficiency of high-capacity wind turbine by applying superconducting coil making high magnetic field. Conventional wind turbines were investigated for up-scaling of generator and the generator had been designed with estimated design parameters using a finite elements method analysis tool.

• 신재생에너지
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• 제6권4호
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• pp.41-49
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• 2010

Over the last decade, wind turbine industry has rapidly increased around world. These days many parts of the wind generators are induction generator. But it has some problems such as gearbox failure, rotor excitation and maintenance. Thus many manufacturers are considered permanent magnet synchronous generator named PMSG and direct drive. PMSG uses NdFeB magnet has many the advantage compare with induction generator. In this study, 3MW class outer rotor type PMSG for wind turbine is proposed. The generator features 2.6m stator outer radius, 1200mm stator length, 81 pole pairs, 14 rated rpm, 42kN/$m^2$ shear force density and 94.2% efficiency. Design and analysis generator using FEM program. Then calculate and derivate no load voltage, losses, conductor temperature. To reduce total harmonic distortion and cogging torque, the stator is applied the stator skewing. And to evaluate the designed generator, compare with other generators by active mass per rating torque and torque density.

• 전력전자학회논문지
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• 제16권5호
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• pp.503-510
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• 2011

본 논문에서는 기설계된 풍력발전제어시스템의 최적화에 관한 연구로서, 특히 블레이드 피치제어기 및 발전기 토크 제어기의 제어 변수 튜닝 (Tuning) 기법을 제안하고자 한다. 일반적으로 제어기 설계는 간략화된 수학적 모델을 기반으로 이루어지고 실제 적용시 설계단계에서 고려하지 않았거나 수학적 표현이 불가능한 불확실성을 제어 시스템에 반영하기 위하여 반복적인 시험 단계가 필요하다. 본 논문에서는 풍력발전시스템 비선형 시뮬레이션 소프트웨어와 최적화 기법을 이용하여, 풍력발전기의 로터 회전 속도 변화, 발전기 출력 변동, 동력 전달축 비틀림 진동을 최소화하기 위한 제어기 튜닝 절차 및 결과를 제시하고자 한다. 제어기 기본 설계안과 최적화된 최종 설계안의 비교를 통하여 방법의 타당성을 예시하였다.

• International Journal of Control, Automation, and Systems
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• 제3권4호
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• pp.533-541
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• 2005

In this paper, a wind turbine with power splitting transmission, which is realized through a novel three-shaft planetary, is presented. The input shaft of the transmission is driven by the rotor of the wind turbine, the output shaft is connected to the grid via the main generator (asynchronous generator), and the third shaft is driven by a control motor with variable speed. The dynamic models of the sub systems of this wind turbine, e.g. the rotor aerodynamics, the drive train dynamics and the power generation unit dynamics, were given and linearized at an operating point. These sub models were integrated in a multidisciplinary dynamic model, which is suitable for control syntheses to optimize the utilization of wind energy and to reduce the excessive dynamic loads. The important dynamic behaviours were investigated and a wind turbine with a soft main shaft was recommend.

• KEPCO Journal on Electric Power and Energy
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• 제5권3호
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• pp.229-233
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• 2019

Large-scale High Temperature Superconducting (HTS) wind power generators suffer from high electromagnetic force and high torque due to their high current density and low rotational speed. Therefore, the torque and Lorentz force of HTS wind power generators should be carefully investigated. In this paper, we proposed a Performance Evaluation System (PES) to physically test the structural stability of HTS coils with high torque before fabricating the generator. The PES is composed of the part of a pole-pair of the HTS generator for estimating the characteristic of the HTS coil. The 10 MW HTS generator and PES were analyzed using a 3D finite element method software. The performance of the HTS coil was evaluated by comparing the magnetic field distributions, the output power, and torque values of the 10 MW HTS generator and the PES. The magnetic flux densities, output power, and torque values of the HTS coils in the PES were the same as a pole-pair of the 10 MW HTS generator. Therefore, the PES-based evaluation method proposed in this paper can be used to estimate the critical characteristics of the HTS generator under high magnetic field and high torque before manufacturing the HTS wind turbines. These results will be used effectively to research and manufacture large-scale HTS wind turbine generators.