• 한국전자통신학회논문지
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• 제15권5호
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• pp.923-930
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• 2020

현대 사회에서 다양한 전기기기들의 시스템 회로를 동작시키기 위해서는 여러 직류 전원이 필요하다. 회로의 정상적인 동작을 위해 안정된 직류의 공급이 필수적으로 요구되고 이를 위한 컨버터의 중요성은 매우 크다고 할 수 있다. 본 연구는 부하 변동에 상관없이 출력전압의 안정적인 공급을 유지할 수 있도록 승압형 DC-DC 컨버터인 KY 컨버터에 3-극점 2-영점 전압 제어기를 적용한 PWM DC-DC 컨버터 회로를 제안하였다. 제안된 컨버터 회로의 정상 동작 특성을 입증하기 위해 기존의 컨버터 회로와 비교하여 PSIM 시뮬레이션 프로그램과 PCB 기판에서의 회로 동작 실험을 수행하였다.

• 제어로봇시스템학회논문지
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• 제18권4호
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• pp.371-374
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• 2012

DC/DC switching power converters produce DC output voltages from different stable DC input sources regulated by a bi-polar transistor. The converters can be used in regenerative braking of DC motors to return energy back in the supply, resulting in energy savings for the systems containing frequent stops. The voltage mode DC/DC converter is composed of a PWM (Pulse Width Modulation) controller, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), an inductor, and capacitors, etc. PWM is applied to control and regulate the total output voltage. It is shown that the output of DC/DC converter depends on the variation of threshold voltage at MOSFET and the variation of pulse width. In the PWM operation, the missing pulses, the changes in pulse width, and a change in the period of the output waveform are studied by SPICE (Simulation Program with Integrated Circuit Emphasis) and experiments.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.30-37
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• 2018

Unlike an AC system, a DC system does not cause problems with synchronization, stability, reactive power, system losses, and cost. However, more research is still required for the application of DC Systems. This paper proposes a stable black-start strategy for a stand-alone DC micro-grid, which consists of an energy storage system, photovoltaic generator, wind-turbine generator, diesel generator, and DC loads. The proposed method is very important for avoiding inrush current and transient overvoltage in the power system equipment during restoration after a blackout. PSCAD/EMTDC software was used to simulate, analyze, and verify the method, which was found to be stable and applicable for a stand-alone DC micro-grid.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1056-1057
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• 2015

A common DC bus is a useful connection for several DC output sources such as photovoltaic (PV), fuel cells, and batteries. Operation of the common DC power system with more than two DC output sources, especially in a stand-alone mode, requires a control scheme for the stable operation of the system. In this paper, a control scheme has been developed for applying DC power sources to the distribution system. The purpose of the control scheme is to make the best use of the DC power sources. The DC power system consists of PV, two energy storage systems and a DC-AC inverter with the control scheme. A distribution system was modeled in PSCAD/EMTDC. As the results, the control scheme is applied to the DC-AC inverter and the DC-DC converter for transfer operations between the grid-connected and the stand-alone mode to keep the DC bus and the AC voltage constant. The results from the simulation demonstrate the stable operation of a grid connected DC power system.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.261-265
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• 2005

본 논문에서는 하이브리드 자동차용 보조전원 공급이 목적인 DC-DC Converter에 대하여 기술하였다. DC-DC Converter는 차량 내의 헤드램프, 오디오, 각종 ECU등 전기/전자 부하에 전력을 공급하며 또한 12V 보조 배터리를 충전하는데 사용된다. 고주파 동작 조건하에서 유기되는 전자파 노이즈와 스위칭 손실을 저감하기 위하여 컨버터 토폴로지로 위상천이 영전압 풀브리지 방식을 적용하였으며 제어기의 용이한 보상 및 안정된 시스템 응답 특성을 위하여 슬로프 보상이 포함된 전류 모드 제어방식을 사용하였다 정전압/정전류 충전 제어 방식은 전기부하에 안정적인 전원공급과 보조 배터리의 안정적인충전을 보장한다. 초기의 회로 파라메타 설정 및 하드웨어 디버깅을 위하여 시뮬레이션 툴로 PSIM 6.0을 사용하였으며. DC-DC Converter에서 스위칭 소자의 발열문제는 Thermo Tracer 장비를 사용하여 개선하였다.

• Journal of information and communication convergence engineering
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• 제7권2호
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• pp.107-112
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• 2009

Renewable energy resources will be an increasingly important part of power generation in the new millennium. Besides assisting in the reduction of the emission of greenhouse gases, they add the much needed flexibility to the energy resource mix by decreasing the dependence on fossil fuels. Due to their modular characteristics, ease of installation and because they can be located closer to the user, PV system have great potential as distributed power source to the utilities. In this paper, a dc-de power converter scheme with the push-pull based technology is proposed to apply for solar power system which has many features such as high efficiency, stable output, and low acoustic noises, DC-DC converter is used in proposed topology has stable efficiency curve at all load range and very high efficiency characteristics. This paper presents the design of a single-phase photovoltaic inverter model and the simulation of its performance.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 추계학술대회 논문집
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• pp.234-237
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• 1996

The amorphous chalogenide semiconductors are new material in semiconductor physics. Their properties, especially electronic and optical properties are main motives for device application. Amorphous As$_{10}$Ge$_{15}$ Te$_{75}$material has the stable ac conductivity at high frequency and the dc memory switching property. At higher frequency than 10MHz, ac conductivity of As$_{10}$Ge$_{15}$ Te$_{75}$ thin film is much higher than below frequency and independent of temperature and frequency. If the dc voltages are applied between edges of thin film, one can see the dc memory switching phenomenon, in other words the dc conductivity increases quite a few of magnitude after the threshold voltage is applied. Using the stable ac conductivity at high frequency and the increase of conductivity after dc memory switching, As$_{10}$Ge$_{15}$ Te$_{75}$thin film is considered as new material for microwave switch devices.vices.es.vices.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.442-442
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• 2000

The intelligent auto-tuning method fur a strongly stable adaptive control system of a DC motor with great load inertia variation is proposed. The stable characteristic polynomial that is designed by an optimal servo is specified for the adaptive pole placement control system. The appropriate adaptive control system can be derived, by adjusting automatically the weight of a performance criterion in optimal control by means of the fuzzy inference on the basis of the stability index.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.598-599
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• 2010

Low Voltage DC/DC Converter(LDC) is the power conversion unit for suppling the power to the auxiliary battery and the electric loads on vehicle. LDC has the capabilities of stability and efficient control method so that the electric loads are fully functional. This paper proposes a control method based on one PI-controller and verifies the stable performance from simulation.

• 대한기계학회논문집B
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• 제30권8호
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• pp.756-763
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• 2006

PEMFC has several technical problems such as water management, long term stability and performance degradation as. PEMFC has been studied not only to solve water management, but also to generate power in stable manner to system by using a hybrid system with auxiliary energy storage device. The purpose of this study is to couple PEMFC with supercapacitor to make a hybrid system and to design and test control strategies for stable power generation in case of changing output power. The polarization curve and dynamic behaviors while changing power were investigated to find out characteristics of PEMFC stack. A DC/DC converter was fabricated in order to increase fuel cell and supercapacitor voltage and to charge supercapacitor. We found that the operation strategy 2 was recommended to the system because of solving water management problem and increasing the dynamic behavior.