• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.283-286
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• 2001

본 논문은 전력 품질개선장치인 DVR(Dynamic Voltage Restorer)시스템의 제어알고리즘 개발에 관한 것이다. DVR은 배전전계통에 직렬변압기를 통해 설치되어 전원의 순간전압강하(Voltage sag)를 보상하는 장치이며 전력변환장치 직렬변압기 에너지저장장치, 충전장치, 보호장치등으로 구성된다. 지락사고, 비선형부하의 순간투입, 뇌서지등 여러 요인에 의해 3상전원에서 발생하는 다양한 형태의 전압sag 보상이 가능한 제어알고리즘 모델을 제시하고 컴퓨터시뮬레이션을 통해 기본성능을 확인한 후 소형 DVR을 제작해 시험하였으며 이시험결과를 실 용량 DVR시제품의 설계에 이용하였다.

• Journal of Power Electronics
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• v.13 no.2
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• pp.304-312
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• 2013

The most common power quality problems in distribution systems are related to unbalanced voltage sags. Voltage sags must be detected quickly and corrected in a minimum amount of time. One of the most widely used methods for sag detection is based on the d-q transformation. This method has the disadvantage of missing the detection of unbalanced faults, because this method uses a voltage sag level signal obtained from the average of 3 phases for sag detection. In this paper, an adaptive filter sag detection method is proposed for Dynamic Voltage Restorers (DVR) under unbalanced fault conditions. The proposed DVR controller is able to detect balanced, unbalanced and single phase voltage sags. A novel reference voltage generation method is also presented. To validate the proposed control methods, a 3-phase DSP controlling a DVR prototype with a power rating of 1.5-kVA has been developed. Finally, experimental results are presented to verify the performance of the proposed control methods.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.803-807
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• 2001

This paper presents a new control scheme for a DVR (Dynamic Voltage Restorer) system consisting of series voltage source PWM converters. To control the negative sequence components of the source, it is necessary to detect the negative sequence components. Generally, a filtering process is used which has some undesirable effects. This paper suggests a new method for separating positive and negative sequences components. This control system is designed using differential controllers and digital filters. The positive and negative sequences are extracted and controlled individually. The performance of the presented controller and scheme are confirmed through simulation and actual experiment with a 2.5kVA prototype DVR system.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.404-409
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• 2003

This paper discusses how to generate the reference compensation voltages in Dynamic Voltage Restorers (DVR) by use of PQR power theory Sensed three-phase terminal voltages are transformed to PQR coordinates without time delay. Since the reference voltages in PQR coordinates are do values, the voltage controller for DVRs is simple and easy to design. Proposed control method can be implemented by feedforward controllers or by feedback controllers. This paper verified the theory in the feedforward controller of a DVR by experiments.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.458-461
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• 2008

This paper deals with a single-phase impedance-source dynamic voltage restorer (Impedance-DVR) to mitigate voltage sag/swell for the critical loads. The proposed system is composed of passive filter and impedance-source topology inverter. As an ESS(Energy Storage System) of the proposed system is employed the Proton Exchange Membrane Fuel Cells (PEMFC). To calculate and control the compensation voltage, single-phase $^id-^iq$ theory in dq rotating reference frame and PI controller are used. Simulation results under voltage sag and swell are presented to show the performance.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.147-150
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• 2007

This paper describes the development of a high-performance single-phase line-interactive Dynamic voltage Restorer, which is composed of an H-bridge inverter and super-capacitors. The operational feasibility was verified through computer simulations with PSCAD/EMTDC software, and experimental works with 3kVA prototype. The developed system can compensates the input voltage sag and interruption within 2ms, in which the maximum allowable duration of voltage interruption is 1.5 seconds. The developed system has a simple structure to be easily implemented with commercially available components and to be highly reliable in operation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.8
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• pp.42-49
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• 2012

Grid-connected photovoltaic generator system requires high performance PCS(Power Conditioning System) according to the standard of 'Distributed Generation Grid-Connected Technology Standards'. This paper presents the MPPT control method which improves output efficiency through fast tracking to the maximum power point of PV and a reduced self-excited vibration. Secondly, in this paper DVR function was applied to PCS to compensate the voltage sag frequently happening for a power system. The proposed PCS control is analyzed and compared to conventional PCS operating characteristic, the various insolation and loads, and voltage sag condition through PSIM tool. It proves the utility.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2251-2252
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• 2008

Recently, voltage sag from sudden increasing loads is also one of the major problems inside the utility network. In order to compensate the voltage sag problem, power compensation device systems could be a good solution method. In case of voltage sag, an energy source is needed to overcome the energy loss caused by the voltage sag. Superconducting Magnetic Energy Storage (SMES) is a very promising source of this energy due to its fast response of charging and discharging time. Before constructing the power electronic delivering system for the SMES, it is necessary to simulate the system to understand its behavior. Nowadays, a lot of devices have been developed to compensate voltage sag such as Dynamic Voltage Restorer (DVR), Distribution Static Compensator (D-STATCOM) and Uninterruptible Power Supply (UPS). In this paper, focus is given only on DVR system which will be simulated by using PSCAD/EMTDC software.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.1
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• pp.7-12
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• 2006

This paper proposes the new voltage event detection method using the weight factor of neural network and describes control system design for the DVR(Dynamic Voltage Restorer) consisted of a rectifier and series inverter applied to 22.9kV distribution system. As this method can express the fault level of each phase, we expect the proposed method can make up for disadvantage of synchronous detection method. Also, in this paper, the control system was designed using double deadbeat controller, As it has an inner current control loop and an outer voltage control loop, we can easily limit the current level during the transient intervals by using the current control loop. Simulation and experiment are performed to prove the analysis of the voltage event detection method and double deadbeat controller.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.424-427
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• 2006

본 논문에서는 DVR 시스템 구성을 위한 환경친화적 EDLC(전기이중층콘덴서)의 특성해석에 관한 연구를 수행하였다. 순시적인 전압 새그 발생시 급속 충 방전 및 에너지 밀도를 고려한다면 기존 전해캐패시터 보다는 EDLC의 채용이 적당하다. EDLC를 채용한 DVR시스템에서 EDLC의 등가직렬저항 및 정전용량 등은 DVR 인버터의 부하 용량 결정에 따른 보상시간을 결정하므로 이의 내부 특성을 해석할 수 있어야만 한다. 따라서 본 연구에서는 EDLC의 내부 파라미터 추출기법 및 구동부의 DC/DC 컨버터에 관한 해석을 수행하고 EDLC를 채용한 DVR의 구성에 따른 실험결과를 제시한다.