• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.296-300
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• 2001

Novel concept of shunt active filter (AF) function added in Photovoltaic (PV) generation system is described in this paper. So far, for the PV generation system has been treated as one of harmonic sources to the power distribution systems, not only a PV system combined with AF but also AF systems using PV module as their power source have never been discussed. The basic structure and control strategy of the PV-AF system are, for the first time, introduced in this work. In order to stabilize the output current of voltage source inverter (VSI), the reference voltage MPPT control is applied. Simulation analysis shows that it is possible to combine AF function to the three-phase grid-connected PV generation system without any physical difficulties, and the performance of the proposed PV-AF system is acceptable and stable as well.

• 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.

• 조명전기설비학회논문지
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• 제25권8호
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• pp.48-59
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• 2011

This paper presents a new gain scheduling speed controller of permanent magnet synchronous generators(PMSG) for MW-class direct-driven wind turbine systems. The proposed gain scheduling speed controller performs the speed tracking at more than one operating point, and the first-order torque observer estimates the turbine torque which is needed to precisely control the speed of PMSG. The proposed speed controller verifies that the PMSG can successfully follow the reference speed which is determined via the maximum power point tracking(MPPT) control and pitch control under turbulent wind conditions. The proposed speed control algorithm is simulated using Simulink and its performance is confirmed through comparison with the results by PI control method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.1498-1500
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• 2004

A novel technique for efficiently extracting maximum power from PV panels is proposed, consisting of a modified buck-boost converter, witch is controlled by a DSP. A variation of the proposed MPPT technique is directly use the modified buck-boost converter current reference as a control parameter. Also 4 parallel boost converters have division of load. A theoretical analysis of the proposed converter is performed and compared with experimental results obtained from a 1k[W] prototype solar panel under a controlled experimental setup.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권4호
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• pp.208-216
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• 2005

Recently, the study of islanding phenomenon, maintains its operation even when the utility grid is removed has lead to the trend of utility interactive inverters in photovoltaic generation systems. In this paper, a novel Anti-islanding method is presented. the proposed method can keep the real average power component constant by MPPT control and cause the load current frequency with only change of reactive power component under the islanding condition. its periodical change of Reactive power component can decrease the NDZ(Non-Detective zone) so that the detection of various loads will be possible. the insufficient effect if additional reactive power component to the grid is proved theoretically and the islanding detection is also confirmed from a experimental result with a inverter for 3kW photovoltaic generation system applied the proposed Anti-islanding method.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.235-237
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• 2007

최근 신재생 에너지로 풍력 발전 시스템이 중요시 되고 있다. 이에 본 논문에서는 풍력발전 시스템의 Wind Turbine System을 영구자석형 동기기를 이용하여 시뮬레이션 모델을 구현하였다. 시뮬레이션 모델은 회전자 모델, MPPT 알고리즘, 영구자석형 동기기(PMSM) 등으로 구성되어있다. Wind Blade Rotor의 유체역학적 특성 및 가감속 제어전략을 이용하여 Wind Turbine System의 특성을 시뮬레이션 할 수 있도록 하였다. 본 연구 결과는 이후 영구자석형 동기기를 이용한 풍력발전기의 기초 자료로서 이용될 수 있을 것으로 기대된다.

• 전력전자학회논문지
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• 제18권5호
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• pp.485-491
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• 2013

A new passive lossless snubber for boost converter based on magnetic coupling is proposed. It is composed of a winding coupled with boost inductor, one snubber inductor, two snubber capacitor and three additional diodes. Especially, the snubber inductor can not only limit the reverse recovery current of output diode but also minimize switch turn-on losses greatly. Moreover, all of the energy stored in the snubber is transferred to the load in the manner of resonance. To confirm the validity of proposed system, theoretical analysis, design consideration, and verification of experimental results are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1687-1688
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• 2006

This paper presents the results of a grid-connected photovoltaic (PV) system modeling that contain incremental conductance MPPT(Maximum Power Point Tracking) controller by PSCAD/EMTDC simulator and investigates the influence that tan occur in the grid-connected PV system from aspect of power quality, i.e. voltage drop, total harmonic distortion(THD) and total demand distortion(TDD). The measured data the PV array modeling of PSCAD/EMTDC in Cheongwadae, Seoul, Korea is used in the paper.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 추계학술대회 논문집
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• pp.69-73
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• 2002

A study on photovoltaic system has a lot of problems. Such as repetition experiment in the same condition, development of MPPT(Maximum Power Point Tracking) algorithm, development of islanding detection algorithm and so forth. The reason Is that solar cell output characteristics are varied by insolarion and surface temperature of solar cell. Therefore, the assistance equipment is required which emulates the solar cell characteristics. In this paper, propose the new modeling of solar cell and verify this modeling using MATLAB simulation. And experiment virtual implement of solar cell system using this modeling.

• 전력전자학회논문지
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• 제2권4호
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• pp.11-18
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• 1997

태양광 발전시스템의 발전출력은 일사량과 온도에 따라서 크게 변동하고, 태양전지 어레이와 병렬로 연결되는 축전지의 전압에 의해 변동한다. 이 대책으로 지금까지 MPPT 제어(최대출력점 제어)를 해왔는데, 이 제어방식은 손실이 크고 비용이 많이 든다. 따라서 본 논문에서는 이러한 PV 시스템 구성요소의 매칭 손실저감을 위하여 PSpice를 이용한 구성요소의 전자 모델링을 행하고, 태양전지 어레이와 축전지 및 인버터 입력전압의 최적 전압구성법에 대한 연구 결과에 대하여 기술하고 있다. 축전지 최적전압은 태양전지 어레이 최적전압의 약 90%정도가 적당하다는 결과를 얻었다.