• 전력전자학회논문지
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• 제5권6호
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• pp.544-551
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• 2000

In this paper, 3-phase hybrid series active power filter for compensate current harmonics, voltage drop and unbalanced voltage in the network presented. The proposed system is implemented with a space vector modulation voltage source inverter and a high pass filter connected in parallel to the power system. Here the load is six-pulses thyristor rectifier. The phase angle detected in order to generation reference voltage at load terminal is synchronized with the positive sequence component of the unbalanced source by using symmetrical component transformation. The proposed system has an function harmonic isolation between source and load, voltage regulation, and unbalance compensation. Therefore, what the power system is improved quality, the source current is maintained as a nearly sinusoidal waveform and the load voltage is regulated with a rated voltage regardless of the source variation condition. To verify the validity of the proposed compensating system, the computer simulation and experiment are carried out.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.931-932
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• 2006

This paper proposes a control algorithm for 3-phase 4-wire series active power filter. This control algorithm compensates harmonics and neutral line currents which are generated by balanced or unbalanced nonlinear loads. The advantage of this control algorithm is direct extraction of compensation voltage references. Therefore, calculation time is shorten and the performance of series active power filter is improved. Compensation principle of the proposed control algorithm is presented in detail. Experimental results are shown to verify the effectiveness of the proposed control algorithm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.844-847
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• 1997

Countermeasure for instability due to sudden changes like electric short circuit, line switching, generation/load dropping etc. in power systems have been sought in terms of intentional or controlled network changes such as series/shunt compensation and generation/load rejection etc. This paper presents the comparison of stability improving effects by series and shunt compensation for the first swing step out phenomena of a large capacity generating station.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제2B권4호
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• pp.191-200
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• 2002

When power consumption increases, power supply must be efficient and reliable for good power quality. The studies on compensation system of power quality are processing actively. Voltage sag among of factors for power quality is generally PI dual control that voltage sag compensation is used. But this control is no more available since of 120[KHz] ripple rejection. So we proposed the control algorithm using PID control in 3-phase unbalanced power system and the series voltage compensator, when voltage sag occurs.

• Journal of Power Electronics
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• 제11권4호
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• pp.576-582
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• 2011

This paper presents a novel control strategy for selective compensation of power quality (PQ) problems, depending upon the limited rating of voltage source inverters (VSIs), through a unified power quality conditioner (UPQC) in a three-phase four-wire distribution system. The UPQC is realized by the integration of series and shunt active power filters (APFs) sharing a common dc bus capacitor. The shunt APF is realized using a three-phase, four-leg voltage source inverter (VSI), while a three-leg VSI is employed for the series APF of the three-phase four-wire UPQC. The proposed control scheme for the shunt APF, decomposes the load current into harmonic components generated by consumer and distorted utility. In addition to this, the positive and negative sequence fundamental frequency active components, the reactive components and harmonic components of load currents are decomposed in synchronous reference frame (SRF). The control scheme of the shunt APF performs with priority based schemes, which respects the limited rating of the VSI. For voltage harmonic mitigation, a control scheme based on SRF theory is employed for the series APF of the UPQC. The performance of the proposed control scheme of the UPQC is validated through simulations using MATLAB software with its Simulink and Power System Block set toolboxes.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권5호
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• pp.221-228
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• 2001

In this paper, a new control algorithm of series active power filter is proposed to reduce harmonic generated from nonlinear load in power system. In conventional control algorithm, harmonic current must be calculated firstly, and then compensation voltage was calculated by using the results but the proposed control algorithm can calculate compensation voltage directly. Compensating principle of proposed control algorithm is presented in detail. A combined system of series active filter and passive filter is composed in order to experiment. Experiment was carried out to verify proposed control algorithm of series active filter and experimental results are analyzed.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권12호
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• pp.714-722
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• 2002

This paper presents a control algorithm for a 3-phase 4-wire series active Power filter. This control algorithm compensates harmonics, input power factor and neutral line currents which are generated by balanced or unbalanced nonlinear loads. The advantage of this control algorithm is direct extraction of compensation voltage references. Therefore, the calculation time is shortened and the performance of the series active power filter is improved. The compensation principle of the proposed control algorithm is presented in detail. A 3KVA laboratory prototype of the three-phase four-wire series active power filter was built and experiments have been carried out. Experimental results are shown to verify the effectiveness of the proposed control algorithm.

• 전력전자학회논문지
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• 제6권5호
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• pp.386-393
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• 2001

본 논문에서는 3상 3선식 전력시스템에서 전류 고조파와 전원 전압 불평형을 보상하는 직렬형 능동전력필터에 관하여 연구하였다. 직렬형 능동전력필터는 병렬형 수동필터와 병용으로 구성되어져 수동필터의 고조파 보상 능력을 향상시켜주며, 전원측의 전류 고조파를 더욱 저감시키고, 전원 전압의 불평형을 보상하여 부하측에 평형한 전원조건이 형성되도록 보상해 준다. 제안하는 제어 알고리즘은 전류 고조파 보상을 위한 방법과 전원 전압 불평형을 보상하는 방법으로 나누어지며 최종적인 보상 전압은 계산되어진 두 가지 보상 전압의 합의 형태가 되겠다. 전류 고조파 보상을 위한 보상 지령 전압은 정의되어진 성능함수에 의해 계산되어지며, 전원 전압 불평형 보상을 위한 보상 지령 전압은 동기 좌표를 이용하여 계산되어진다. 실험을 통하여 제안하는 알고리즘의 우수성을 입증하였다.

• 전력전자학회논문지
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• 제5권5호
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• pp.484-492
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• 2000

본 논문에서는 고조파전류 보상기능을 갖는 전압 보상기에 관한 연구를 수행하고 그 보상 특성을 해석하였다. 제안된 보상시스템은 하이브리드형 능동전력필터에서와 같이 LC로 구성되어 전력선에 병렬로 연결되는 수동필터와 직렬 변압기를 사용하여 전력선에 직렬로 연결되는 PWM 컨버터를 동시에 사용하는 회로구조를 갖는다. 제안된 보상시스템을 통해 다이오드 정류기와 같은 비선형 부하로 인해 발생되는 고조파 전류의 보상 및 전원 이상 현상으로 발생되는 전원측 이상 전압의 보상을 모두 수행한다. 단상 등가회로를 통해 보상시스템의 동작 원리를 설명하고 d-q 동기좌표계 축 상에서 보상시스템의 모든 제어를 수행하는 제어 알고리즘의 개발을 수행하였으며 실험을 통해 제안된 보상시스템의 보상특성을 확인하였다.

• 전기학회논문지
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• 제61권2호
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• pp.199-208
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• 2012

This paper proposes a quasi Z-source DVR(Dynamic Voltage Restorer) system with a series connection of the output terminals, to compensate the voltage variations in the 6.6[kV]/60[Hz] power distribution system. The conventional DVR using one quasi Z-source AC-AC converter has the advantage which it can compensate the voltage variations without the need for the additional energy storage device such as a battery, but it is impossible to compensate for the 50[%] under voltage sags. To solve this problem, a DVR system using two quasi Z-source AC-AC converters with the series connection of the output terminals is proposed. By controlling the duty ratio D in the buck-boost mode, the proposed system can control the compensation voltage. For case verification of the proposed system, PSIM simulation is achieved. As a result, in case that the voltage sags-swells occur 10[%], 20[%], 60[%] in power distribution system, and, in case that the 50[%] under voltage sags-swells continuously occur, all case could compensate by the proposed system. Especially, the compensated voltage THD was examined under the condition of the 10[%]~50[%] voltage sags and the 20[${\Omega}$]~100[${\Omega}$] load changes. The compensated voltage THD was worse for the higher load resistances and more severe voltage sags. Finally, In case of the voltage swells compensation, the compensation factor has approached nearly 1 regardless of the load resistance changes, while the compensation factor of voltage sags was related to the load variations.