• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.4
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• pp.705-715
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• 2007

Recently, the interest on power quality has been hot issue because the equipments cause voltage disturbance and have become more sensitive to the voltage disturbance. Additionally, the reseach on power electronic equipments applying to the high power has been increased. This paper deals with Line-Interactive Dynamic Voltage Restorer(LIDVR) system using 7-Level H-Bridge inverter, which is one of the solutions to compensate the voltage disturbance and to increase the power of equipments. The LIDVR has the following advantages comparing to the DVR with the series injection transformer. It has the power factor near to unity under the condition of normal source voltage, can compensate the harmonic current of the load and the instant interruption, and has the fast response. First, the construction, the operation mode and algebraic modeling of LIDVR are reviewed. And then the voltage control algorithm is proposed to get the sinusoidal load voltage with constant amplitude. Finally, simulation and experiment results verify the proposed LIDVR system.

• Journal of Power Electronics
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• v.4 no.3
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• pp.180-187
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• 2004

This paper proposes a new control strategy for the dynamic voltage restorer (DVR). It is based on a synchronous PI decoupling control strategy which features fast response time and low steady state error. Therefore, the proposed control strategy produces faster action time against voltage sag and guarantees more than enough compensation for reduced supply voltage. Experimental results, implemented with the TMS320C3${\times}$DSP control unit, are shown to validate the effectiveness of the proposed control strategy.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.4
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• pp.203-209
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• 2002

This paper presents a new control scheme for a DVR(Dynamic Voltage Restorer) system consisting of series voltage source PWM converters. To control negative sequence component of source voltage the detection of negative sequence is necessary. Generally, filtering process is used tn do that. Through this filtering process has some problems. This paper suggests a new method of separating positive and negative sequences. This control system is designed using differential controllers and digital filters, and positive sequence and negative sequences are controlled respectively. The performance of the presented controller and scheme are confirmed through simulation and actual experiment by 2.5kVA prototype DVR.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.11
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• pp.54-61
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• 2012

This study investigated the relationship between the response time of DVR (Dynamic Voltage Restorer) and the possible compensation range for voltage dips by the DVR system which protects the 3-phase phase-controlled rectifier from said dips. As a result, the permissible range of voltage dip is presented in a 3-phase phase-controlled rectifier. When the DVR compensates for voltage dip, the range of voltage dip can be compensated according to the DVR's response time. Using the proposed method, DVR response time can be determined from the parameters of the 3-phase phase-controlled rectifier and the possible compensatory range of voltage dip, while at the same time it is possible to use a control system having an appropriate speed. Therefore, the use of excessively fast equipment can be avoided, improving the stability of the overall system. The reliability of the DVR concerning the 3-phase phase-controlled rectifier can be verified by simulation.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.554-559
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• 2003

A new control strategy for dynamic voltage restorer (DVR) is proposed. It is based on synchronous PI control strategy which features fast response. Therefore, the proposed control strategy takes faster action against a voltage sag. Experimental results, executed by DSP, are shown to validate the proposed control strategy.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.69-71
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• 2008

Recently, the interest on power quality has been hot issue because the equipments cause voltage disturbance and become more sensitive to the voltage disturbance. The DVR(Dynamic Voltage Restorer) is one of the Custom Power Device that can compensate the voltage. DVR operates as a series connected compensator whose output voltage can be controlled system voltage. And the magnitude of compensation voltage is limited by the characteristics of system and load. Compensation capability of DVR was simulated by EMTDC under several condition. This paper analyzed effect of DVR's compensation at power quality test center which has SSFG(Sag, swell, and Flicker Generator, CPDs(SSTS, DVR, DSTATCOM), and loads.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.5
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• pp.435-441
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• 2003

Dynamic Voltage Restorers (DVR)s are known as the best effective and economic means to compensate for voltage sags and swells. This paper proposes a novel method to generate reference voltages synchronized with the grid whether the line voltages are distorted by a fault or not. The proposed reference wave generator (RWG) looks for the original wave forms from the corrupted line voltages and synthesizes the expected positive sequence reference waves for DVRs. There is no transient problem on the generated reference waves when the line voltages are distorted by the fault.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.9
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• pp.165-171
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• 2010

There are many researches on Power Quality Device to protect the critical load and power system as the nonlinear load and precision load are adopted into the power system recently. To analyze the voltage compensation of voltage sag and voltage swell by DVR, which is connected to the important load in series, this paper shows PSCAD/EMTDC simulation and its verification by comparing with the actual DVR output of 2MVA. DVR control scheme in this paper is applicable to compensate single-phase, 2-phases or 3-phases voltage sag as well as DVR for distribution system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.2
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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.

• Journal of Advanced Navigation Technology
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• v.19 no.5
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• pp.433-439
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• 2015

Recently, Interest in power the quality was increased because of increasing the use of sensitive load equipment into an electrical disturbance such as computer, Electricity, Electronics, Telecommunications and semiconductor device. In addition, To enhance power quality, the instantaneous voltage drop occurred in precision load equipment is a need for proper compensation. In order to solve the problem, The developed dynamic voltage restorer (DVR) using an electric double layer capacitor (EDLC) has been applied. In this paper, We will do study to apply hybrid capacitors that have high energy density to the same size compared to the EDLC to DVR. Also, As a emergency luminaires of emergency power supply that we can support more than 10 years of life was confirmed the applicability of hybrid capacitor.