• Journal of Power Electronics
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• v.9 no.4
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• pp.643-653
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• 2009

Voltage-controlled voltage source inverter (VCVSI) based distributed generation systems (DGS) using renewable energy sources (RES) is becoming increasingly popular as grid support systems in both remote isolated grids as well as end of rural distribution lines. In VCVSI based DGS for load voltage stabilization, the power angle between the VCVSI output voltage and the grid is an important design parameter because it affects not only the power flow and the power factor of the grid but also the capacity of the grid, the sizing of the decoupling inductor and the VCVSI. In this paper, the steady state modeling and analysis in terms of power flow and power demand of the each component in the system at the different values of maximum power angle is presented. System design considerations are examined for various load and grid conditions. Experimental results conducted on a I KVA VCVSI based DGS prove the analysis and simulation results.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.151-153
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• 2008

This paper deals with the electric energy saving system for lighting with power conditioning, which aims at the integration of power quality improvement and energy saving. The system consists of a CCVSI(Current-Controlled Voltage Source Inverter) and VCVSI(Voltage-Controlled Voltage Source Inverter). The CCVSI is connected in parallel to a grid, which can be operated to compensate the reactive power demanded by nonlinear and variation loads. The VCVSI is connected to the CCVSI through the DC capacitor (DC side) and in series on the AC side(lighting load), which can perform the energy saving. The operation of the proposed system is confirmed through the simulation and its usefulness is discussed.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.990-991
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• 2006

본 논문은 우리나라와 같은 안정된 계통(Strong Grid)에서 계통전압이 한전배전계통 공급기준의 전압변동률 ${\pm}6%(220V{\pm}13V)$이내에서 변화할 경우 계통 역률이 0.9 이상이고 부하전압의 변동이 거의 없도록 계통 연계형 전압제어형 전압원인버터(VCVSI)에 적합한 최대 전력제어각과 각각 최적의 시스템 용량(계통, 디커플링 인덕터, VCVSI)을 구하고, 유효전력을 100% 공급하기 위한 파라미터 설계 방법을 제시하였다.

• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.143-145
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• 2008

본 논문에서는 산간벽지 또는 낙도와 같이 중앙계통으로부터 송 배전선을 이용한 전력공급이 어려운 약 계통(Weak grid)에 주로 사용되는 계통연계형 분산전원시스템의 설계 방법을 설명한다. Weak grid에서는 계통의 전압변동의 폭이 매우 크기 때문에 부하에 안정적으로 정전압을 공급할 수 있는 전압제어형 전압원인버터(VCVSI: Voltage-Controlled Voltage Source Inverter)를 주로 사용한다. 따라서 본 연구에서는 계통의 전압에 변동에 따른 각각의 시스템 파라미터 특성을 분석하고 이에 따른 최적의 시스템 용량의 선정방법을 제시한다.

• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.287-289
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• 2009

This paper deals with a parallel processing uninterruptible power supply (UPS) for sudden voltage fluctuation in computer applications to integrate power quality improvement, load voltage stabilization and UPS. To reduce the complexity, cost and number of power conversions, which results in higher efficiency, only one voltage-controlled voltage source inverter (VCVSI) is used. The system provides sinusoidal voltage at the fundamental value of 220V/60Hz for the load during abnormal utility power conditions or grid failure. Also, the system can be operated to mitigate the harmonic current and voltage demand from nonlinear loads and provide voltage stabilization for loads when sudden voltage fluctuation occur, such as sag and swell. System operation simulation demonstrates that the system protects against outages caused by abnormal utility power conditions and sudden voltage fluctuations and changes.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.126-127
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• 2011

본 논문에서는 분산전원용 UPQC(Unified Power Quality Conditioner)에 사용되는 스위칭 알고리즘으로 PRT 기반 전압/제어 알고리즘을 적용한다. 분산전원용 UPQC는 전압제어형전압원인버터(VCVSI:Voltage-Controlled VSI)와 전류제어형전압원인버터(CCVSI:Current-Controlled VSI)를 계통과 직 병렬로 연결한 형태로 PRT 전압/전류 제어 알고리즘을 구동 알고리즘으로 사용하게 되면 회로 구성이 간단하고 제어가 용이한 장점이 있다. 본 논문에서는 PRT 기반 전압/전류 알고리즘을 UPQC에 적용하는 방법을 설명하고, 이의 유용성을 확인하기 위해 시뮬레이션을 수행하였다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1151-1152
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• 2007

본 논문에서는 전력품질개선, 부하수요관리, 무정전전원공급, 부하전압안정화 등의 기능을 통합적으로 수행할 수 있는 전압제어형 전압원인버터(VCVSI: Voltage-Controlled Voltage Source Inverter)를 적용한 계통연계형 분산전원시스템의 제어 알고리즘을 제안하였다. 제안 된 시스템은 계통, 신재생에너지원(또는 배터리) 그리고 부하조건에 따라 3가지 모드(전력품질개선모드. 부하수요관리모드, 무정전전원공급모드)에 따라 동작한다. 본 연구에서는 각각의 모드에 따른 동작특성을 분석하고, 시뮬레이션을 통해 그 유용성을 확인하였다.

• Journal of Electrical Engineering and Technology
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• v.3 no.4
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• pp.546-551
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• 2008

In this paper, a flux-lock type superconducting fault current limiter(SFCL) integrated with a voltage-controlled voltage source inverter(VC-VSI) is proposed. The suggested equipment, which consists of a flux-lock type SFCL and a VCVSI, can perform the fault current limiting operation from the occurrence of a short-circuit. In addition, it can compensate the reactive power that the non-linear load requires and also perform the uninterruptible power supply(UPS) as well as the load voltage stabilization by controlling the amplitude and the phase of the inverter's output voltage. The specification for a test model was determined and its various functions such as the fault current limiting and the power conditioning operations were presented and analyzed via computer simulation. Through the analytical results based on the computer simulation, the validity of the analysis was confirmed and its multi-operation was discussed.