• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.6
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• pp.610-617
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• 2005

A variable speed wind turbine simulation model for grid connection is developed based on PSCAD/EMTDC. The model consists of wind model, rotor dynamics, synchronous generator, power converter, transformer, distribution line and infinite bus. Implementation of blade characteristics and power converter control strategies are included. Several transient case studies are performed including wind speed change, local load change and grid-side voltage unbalance using developed simulation model. The results of this work can be utilized for study of actual interaction between wind turbine and grid for reliable operation and protection of power system.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1116_1117
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• 2009

전력계통에서의 풍력 발전의 설치가 증가하면서 사고 발생시 전체 계통에 대한 신뢰도 및 안정도에 영향을 미친다. 이를 고려한 Fault Ride Through 제어 기법은 보다 안정적인 계통운영을 위한 방안이다. 최근 대부분의 풍력발전시스템은 이중여자 유도형 발전시스템(DFIG)이 설치되는데, 이는 전력변환장치를 이용한 유효 및 무효 전력 제어가 가능한 가변속 풍력발전시스템이다. 본 논문은 PSCAD/EMTDC를 통해 DFIG를 모델링하고 Crow Bar와 Rotor Side Converter의 연계 제어를 이용한 Fault Ride Through 제어 기법을 시뮬레이션 결과를 통해 확인 하였다.

• Proceedings of the KIPE Conference
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• 2008.10a
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• pp.202-205
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• 2008

본 논문은 이중여자 발전기를 사용하는 풍력발전기에서 안정적인 계통투입을 위한 계통연계 전 후 발전기의 인덕턴스 변화에 따른 전류제어기 이득 값 선정에 대하여 연구하였다. DFIG(Doubly Fed Induction Generator)방식을 이용하는 풍력발전기는 회전자 전류제어를 함으로써 고정자의 전압을 제어하고, 제어된 고정자 전압은 계통과 연결된다. 특히 회전자 전류제어기 성능은 LVRT(Low Voltage Ride Through)등 예상하지 않은 외란에 대하여 빠른 응답성을 필요로 한다. 그러나 발전기가 계통과 연계되는 순간 발전기의 내부 파라미터 값의 변동이 발생하며, 이는 계통 투입 전 발전기 파라미터에 근거한 RSC(Rotor Side Converter)측 전류제어기 이득 값에 영향을 미쳐, 전류제어가 불안정하게 하는 원인이 되거나, 전류제어 응답성을 낮추게 하는 요인이 된다. 따라서, 본 연구에서는 계통투입 전 후의 RSC측 전류제어기의 이득 값을 달리하여 안정적인 계통 투입이 가능하도록 하는 알고리즘을 시뮬레이션과 실험으로 증명하였다.

• Journal of Power Electronics
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• v.19 no.2
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• pp.569-579
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• 2019

A robust controller is designed based on feedback linearization and sliding mode control to damp sub-synchronous control interaction (SSCI) in doubly fed induction generator (DFIG) wind power plants (WPPs) interfaced with the grid. A feedback-linearized sliding mode controller (FLSMC) is developed for the rotor-side converter (RSC) through feedback linearization, design of the sliding mode controller, and parameter tuning with the use of particle swarm optimization. A series-compensated 100-MW DFIG WPP is adopted in simulation to evaluate the effectiveness of the designed FLSMC at different compensation degrees and wind speeds. The performance of the designed controller in damping SSCI is compared with proportional-integral controller and conventional sub-synchronous resonance damping controller. Besides the better damping capability, the proposed FLSMC enhances robustness of the system under parameter variations.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.8
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• pp.150-157
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• 2005

This paper presents the simulation modeling and analysis of variable wind speed turbine system(VWTS) using the doubly fed induction generator(DFIG) connected the back to back converter system in the rotor side. In the simulation, using the model system which has the 660[kW] rated power, blade control and the dual converter system are modeled for verifying the control characteristics. The VWTS is controlled by the optimal pitch angle for maximum output power under the rated wind speed, and for the rated output power over the rated wind speed. And also power factor is controlled by the reactive power. To verify the effectiveness of the proposed method, simulation results are compared with the actual data from the V47 VWTS located in Hangwon wind farm in Jeju-Do. According to the comparison of these results, this method shows excellent performance.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1884-1893
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• 2016

The ride-through control of a doubly-fed induction generator (DFIG) for the voltage sags on wind farms utilizing crowbar circuits by which the rotor side converter (RSC) is disabled has being reported in many literatures. An analysis and calculation of the transient current when the RSC is switched off are of significance for carrying out the low voltage ride through (LVRT) of a DFIG. The mathematical derivation is highlighted in this paper. The zero-state and zero-input responses of the transient current in the frequency domain through a Laplace transformation are investigated, and the transient components in the time domain are achieved. With the characteristics worked out from the linear resolving without modeling simplification, the selection of the resistance in the linear crowbar circuit and the value conversion from a linear circuit to a nonlinear one is proposed to setup the attenuation rate. In terms of grid code requirements, the theoretical analysis for the time constant of the transient components attenuation insures the controllability when the excitation of the RSC is resumed and it guarantees the reserved time for the response of the reactive power compensation. Simulations are executed in MATLAB/SIMPOWER and experiments are carried out to validate the theoretical analysis. They indicate that the calculation method is effective for selection of the resistance in a crowbar circuit for LVRT operations.