• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.5
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• pp.484-493
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• 2011

The MPPT algorithm using neuro-fuzzy controller is proposed to improve the performance of fuzzy controller in this paper. The width of membership function and fuzzy rule have an effect on the performance of fuzzy controller. The neuro-fuzzy controller has the response characteristic which is superior to the existing fuzzy controller, because of using the optimal width of the fuzzy membership function through the neural learning. The superior control characteristic of a proposed algorithm is confirmed through simulation and experiment results.

• Journal of the Korean Solar Energy Society
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• v.28 no.3
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• pp.15-20
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• 2008

Building-integrated photovoltaics(BIPV) are increasingly incorporated into new domestic and industrial buildings as a principal or ancillary source of electrical power, and are one of the fastest growing segments of the photovoltaic industry. This paper presents design, operational features analysis, and PCS(Power Conditioning System) of grid-connected 30kW BIPV set up on the library of Dongshin University. For a sustainable photovoltaics system in this area, the data of the BIPV system are collected and analyzed by monitoring system using LabView. PCS of the grid-connected BIPV system, also, is designed for optimal operation with characteristics suggested in this paper.

• New & Renewable Energy
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• v.2 no.2 s.6
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• pp.16-22
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• 2006

This paper present the performance evaluation of PV systems installed at Tibet area of China in order to identity the key factors that determines system operation at a severe climate conditions and promote the cooperation of PV technology between Korea and China. The installed systems consist of 100kW on-grid connected PV systems, BOS(balance of systems), data acquisition and transmission equipments. The Korea side supplied the solar cell, BOS like as inverter, control box and monitoring system. And the Chinese side assembled solar module, constructed site and built control house. It has been shown that the average radiation per monthly from Tibet is 1.5 times larger than that from Mokpo. Also, radiation time from Tibet is 2hour higher than that from Korea.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.286-287
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• 2018

Recently, the development of renewable energy using solar energy is drawing attention. One of these PV systems, the Dual buck Inverter, is one of the topologies used in conjunction with the system, characterized by high efficiency and shoot-through reduction. However, current distortion appears severely in grid connection. So, in this paper, the method of compensation through PR controller was verified through simulation as an analysis of current distortion components and a control method to improve them.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.326-329
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• 1997

This paper deals with the generating power analysis of wound rotor induction generator according to the rotor excitation for use of DFIG (Doubly Fed Induction Generator) system in wind power generation as a part of renewable energy development. In this way, the generating power of wound rotor induction generator can be achieved for a wide range wind speed of supersynchronous and subsynchronous speed.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.51.1-51.1
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• 2010

본 논문에서는 wavelet 변환을 이용하여 태양광 발전 시스템의 계통 전원 고조파를 측정하는 방법을 연구하였다. PCS(Power Conditioning System)는 태양전지의 전력을 교류로 변환하여 계통에 연계시키는 장치이다. 직류에서 교류로 변환할 때 스위칭 노이즈가 발생하고, 전력품질이 약화되게 된다. Wavelet 이론은 시간 파형을 주파수 성분으로 분해할 수 있는 기술이다. 이중에서 MLD(Multi-evel Decomposition)기법은, 계산량이 적으면서도 빠른 시간 내에 고조파 성분들을 알아낼 수 있다. 시스템 모델링과 wavelet 이론 소개, 그리고 컴퓨터 모의실험과 DSP 제어기를 이용한 실험 결과로서 본 연구의 타당성을 입증하였다.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.253-256
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• 2006

This paper shows operating characteristics of DFIG(Double Fed Induction Generator) for wind turbine. The back to back PWM voltage-fed inverter connected between the rotor and grid network operated sub and super-synchronous operating mode, and the vector-controlled DFIG enables the decoupling between active and reactive power as well as between torque and power factor. This paper is validated by simulations and experimental results.

• Convergence Security Journal
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• v.18 no.2
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• pp.3-10
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• 2018

The existing smart grid, which is centered on the power grid, is rapidly spreading to new energy and renewable energy such as heat and gas, which are expressed as smart energy. Smart Energy interacts with electric energy and is connected to wired / wireless network based on IoT sensor based on energy analysis using AI to rapidly expand ecosystem with various energy carriers and customers. However, smart energy based on IoT is lacking in technological and institutional preparation for security compared to efforts to activate the market according to the interests of government and business operators. In this study, we will present Smart Energy 's privacy policy in terms of value system(CPND) of convergence ICT.

• New & Renewable Energy
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• v.8 no.4
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• pp.13-20
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• 2012

This paper describes a transformerless static synchronous campensator (STATCOM) system based on cascade H-bridge multilevel inverter with star configuration. It is designed not only for the dynamic and continuous compensation of the reactive power but also for the improvement of power quality of existing wind power plant. Especially, when the induction generator of wind turbine is directly connected to the grid, reactive power are occurred by exiting current. so a reactive power compensation system based on the cascade H-bridge multilevel STATCOM is proposed because the output power quality and controllability of reactive power are required by grid code in many different countries. Using various The proposed reactive power control strategy using a STATCOM is compared with the conventional scheme using fixed-size of capacitor bank through various simulation results.

• Journal of Power Electronics
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• v.14 no.5
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• pp.946-956
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• 2014

Cascaded H-Bridge (CHB) converters can be directly connected to medium-voltage grids without using transformers and they possess the advantages of large capacity and low harmonics. They are significant tools for providing grid connections in large-capacity renewable energy systems. However, the reliability of a grid-connected CHB converter can be seriously influenced by the number of power switching devices that exist in the structure. This paper proposes a fault-tolerant control strategy based on double zero-sequence voltage injection and DC voltage optimization to improve the reliability of star-connected CHB converters after one or more power units have been bypassed. By injecting double zero-sequence voltages into each phase cluster, the DC voltages of the healthy units can be rapidly balanced after the faulty units are bypassed. In addition, optimizing the DC voltage increases the number of faulty units that can be tolerated and improves the reliability of the converter. Simulations and experimental results are shown for a seven-level three-phase CHB converter to validate the efficiency and feasibility of this strategy.