• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 추계학술대회
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• pp.183-184
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• 2017

엘리베이터의 경우 정전 시 승객을 안전하게 구출하기 위한 장치가 필요하다. 이를 위하여 Auto Rescue Device(ARD) 혹은 Uninterruptible Power Supply(UPS)가 엘리베이터에 설치된다. ARD는 정전 시 배터리의 전압을 승압하여 인버터의 DC 링크 전압을 유지한다. 만약 배터리의 전압보다 DC 링크 전압이 2배 이상 클 경우 일반적인 부스트 컨버터는 효율 등의 문제로 사용이 어렵다. 이에 본 논문에서는 ARD의 특성을 고려한 LLC 공진형 컨버터의 설계 방안에 대하여 서술하였다. 또한 이를 모의실험을 통하여 검증하였다.

• Journal of Power Electronics
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• 제10권1호
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• pp.91-96
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• 2010

In this paper, a simplified control algorithm for a three-phase, four-wire unified power quality conditioner (UPQC) is presented to compensate for supply voltage distortions/unbalance, supply current harmonics, the supply neutral current, the reactive power and the load unbalance as well as to maintain zero voltage regulation (ZVR) at the point of common coupling (PCC). The UPQC is realized by the integration of series and shunt active filters (AFs) sharing a common dc bus capacitor. The shunt AF is realized using a three-phase, four leg voltage source inverter (VSI) and the series AF is realized using a three-phase, three leg VSI. A dynamic model of the UPQC is developed in the MATLAB/SIMULINK environment and the simulation results demonstrating the power quality improvement in the system are presented for different supply and load conditions.

• 한국인터넷방송통신학회논문지
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• 제21권4호
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• pp.123-127
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• 2021

밀리미터파 추적 레이더는 다양한 환경조건에서 운용 가능해야하므로 기존의 추적 레이더에 비해 동등 이상의 연산능력 및 소형화를 요구한다. 본 논문에서는 밀리미터파 추적 레이더에 적용하기 위한 소형 전원공급기 설계 및 구현방안에 대해 기술한다. FPGA/DSP 등 디지털회로의 저전압/고전류 및 전압 정밀도 요구사항 충족을 위해 Point of Load (POL) 컨버터를 적용하였으며, 전력밀도를 향상시키고 시스템 효율을 개선할 수 있다. 부하가 크지 않은 출력전압에는 LDO (Low Dropout) 등을 적용하여 최대 출력 375 W, 출력 전원 8종의 단일 입력-다중 출력 전원공급기를 개발하였다. 최대 부하 조건에서 전압정밀도 <±2 %, 잡음레벨 <50 mVpp 특성을 확인하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.256-256
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• 2013

기존에 사용되어 오던 DCMS (DC magnetron sputtering)과 HPPMS (high-power pulsed magnetron sputtering)에 비해 MPP를 이용한 magnetron sputtering은 높은 증착률을 가지고 있으며, 증착된 박막의 특성도 우수하다고 알려져 있다. 본 연구에서는 최대 출력 700 V, 12.5 A, 100 kHz)의 사양을 가지는 DC, pulse DC, modulated pulsed DC의 세 종류로 변환이 가능한 Power supply를 제작하여 Cr 박막을 증착하였다. 증착시 혼합기체 Ar/$N_2$를 사용하였으며, 박막의 특성을 sputtering power 종류별로 비교 평가하였다. 실험 결과얻어진 박막을 SEM과 XRD를 이용하여 분석하였다.

• Journal of Power Electronics
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• 제10권6호
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• pp.667-672
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• 2010

A way how to teach a general understanding of switched mode power supplies (SMPS) is shown. A fourth order PWM DC-to-DC converter with limited duty cycle range is treated as an example and a survey over important data (maximum voltage and current ratings for the elements, rms- values for the semiconductor devices and a rough approximation of the losses) of the circuit is given. Furthermore, a converter model based on duty ratio averaging is established. Continuous mode of operation is used. The results make it possible to estimate the applicability of the given converter structure and offer sufficient material for the calculation, design, and analysis and give a better insight into switched mode energy conversion.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 전력전자학술대회 논문집
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• pp.443-444
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• 2014

Using the ESS(Energy Storage System) as a UPS(Uninterruptible Power Supply) is being studied recently. When the system is operating at UPS mode in integrated ESS and UPS system, the grid supplying power is disconnected and power from PV generation and battery are supplying to load. Operating in UPS mode, when PV generation power is diminished by partial or total clouded situation, DC-link voltage fluctuates. The fluctuation of DC-link voltage influences the load and system as sensitive loads may malfunction. This paper suggests the DC-link ripple voltage compensation algorithm in bi-directional converter. The algorithm stabilize the DC-link and load voltage.

• 전력전자학회논문지
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• 제14권1호
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• pp.72-81
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• 2009

본 논문에서는 대기압 플라즈마 발생용 정현파펄스형 교류 전원 장치에 대한 연구를 진행하였다. 정현파펄스형 전원장치는 기존의 LC공진을 이용한 교류 전원장치보다 높은 dv/dt를 갖게 되므로 안정적인 플라즈마 공급이 가능하며 펄스형에 비해 고조파 노이즈가 적고, 정전류 턴온-영전압 턴오프 형태로 동작하므로 매우 높은 효율을 갖는다. 또한 플라즈마 점화 기능을 강화하고 안정적인 전압제어를 위해 3상 부스트형 컨버터를 입력단에 사용하여 입력 역률이 매우 높은 시스템을 구성할 수 있다. 실험실 수준의 10kW부하시설을 사용하여 본 연구의 결과를 입증하였다.

• 전기학회논문지
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• 제63권7호
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• pp.1013-1018
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• 2014

This paper described the development of equalizing spacer for minimization of voltage drop according to DC feeder extension. Power consumption is increased as shorter interval of train driving time and transportation capacity increase in urban subway. Therefore we investigated voltage drop of catenary at a point in case of traction driving of a train in parallel to the DC power supply system. Based on it's result, equalizing spacer is designed and fabrication to minimize the voltage drop in accordance with the power supply line arranged in three rows, and then its performance was confirmed that the stress distribution of main body and the distributed load are satisfied through the body structure modeling.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.309-312
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• 2000

Single-phase multi-level AC-DC converter is proposed that is composed of diode bridge and switch. The number of the supply current level is depending on the individual current level of the converter. A converter circuit the number of the level is equal to $\textrm{2}^{M+1}$-1 The proposed circuit has converter with 31 current levels. When the number of current level is increased smoother sinusoidal waveform can be obtained directly and it is possible to control the supply current almost continuously from zero to maximum without step changes of generating high voltage as pulse width modulation switching loss is decreased it has an advantage in large capacity. it is illustrated technique are confirmed the validity and effectiveness through the simulation & experiments

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.878-884
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• 2006

Grounding fault and short of the DC power supply systems are detected and protected by high-speed circuit breaker, linked breaking device, ground relay and fault selective device, all of which are installed and operated in substaions. however, there have been many cases in which the protective devices did not detect grounding of of the over head catenary systems on concrete support for an extended period of time. Such cases often cause severe damages to the supports with high grounding resistances. If grounding accidents occur repetitively, the earth current and the rise of earth potential can damage not only passenger and staff but also electric facilities and equipment, necessitating high cost and endeavor to restore. The following study points out various problems that can be occurred occur as a result of high impedance grounding accident, and proposes a new system which can protect and intercept them.