• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.953-955
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• 2001

This paper presents a new zero current switching (ZCS) inverter for grid-connected photovoltaic single phase inverter system. The auxiliaey circuit for the soft-switching consists of two resonant inductors and two resonant capacitors as well as two auxiliary switches rated at lower power. The proposed circuit provides zero current switching condition for all the switches, which reduces switching losses significantly. It is controlled to extract maximum power from the solar array and to provide sinusoidal current into the mains. The validity of the proposed system is verified by experimental results from the 1.2kW prototype inverter operating at 40kHz.

• 한국전자파학회논문지
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• 제15권6호
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• pp.627-633
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• 2004

순방향 빔형성은 무선 인터넷, VOD(Video-On-Demand), 멀티미디어 서비스 등이 요구되는 최근의 이동통신시스템에서 아주 중요하다. 본 논문은 스마트 안테나 시스템의 순방향 빔형성 구현에 있어서 간과되어서는 안될 필수 고려사항들을 언급하고 이의 성능을 분석한다. 본 논문에서 고려된 사항으로는 캘리브레이션 방법 및 절차, 보조 파일럿 채널의 개념과 그에 따른 단말기 수신 성능, 기지국 HPA전력 할당, 순방향/역방향 처리율 비교 등으로 이는 순방향 빔형성 구현에 있어서 반드시 알고 설계해야 하는 항목이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.131-133
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• 2001

The basic function of a Power-System Stabilizer(PSS) is to add damping to the generator rotor oscillations by controlling its excitation using auxiliary stabilizing signals. To provide damping. the stabilizer must produce a component of electrical torque in phase with the rotor speed deviations. This paper introduces the hardware specifications and various functions of microprocessor (TMS320C32)-based digital PSS to provide the damping torque.

• 전력전자학회논문지
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• 제1권1호
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• pp.20-26
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• 1996

The common drive method of the single phase induction motor(SPIM) is to install a start capacitor and a centrifugal switch in series with the auxiliary winding. In this paper, the phase angle voltage sequence controller is proposed to eliminate a start capacitor and a centrifugal switch of SPIM. In comparison with the capacitor start system of SPIM, the proposed control system shows that it contributes to saving the starting current about 57% and to improving of the starting efficiency of SPIM. The proposed starting characteristics of the SPIM is obtained with this strategy through simulation and experimental results.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 추계학술대회 논문집
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• pp.121-123
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• 2008

A high efficiency soft switching boost converter is proposed in this paper. The conventional boost converter generates switching losses at turn on and off. Because of those, the whole system efficiency is reduced. The proposed converter utilizes soft switching method using resonant circuit with an auxiliary switch. Therefore, the proposed converter reduces switching losses lower than the hard switching. The proposed soft switching boost converter can be applied to photovoltaic system, power factor correction circuit and etc.

• 시스템엔지니어링학술지
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• 제15권1호
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• pp.1-8
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• 2019

Reverse engineering involves examining a system or component so as to comprehend its structure, functionality, and operation. Creation of a system model in reverse engineering can serve several purposes: test generation, change impact analysis, and the creation of a new or modified system. When attempting to reverse engineering a system, often the most readily accessible information is the system description, which does not readily lend itself to use in Model Based System Engineering (MBSE). Therefore, it is necessary to be able to transform this description into a diagram, which clearly depicts the behavior of the system as well as the interaction between components. This study demonstrates how sequence diagrams can be extracted from the systems description. Using MBSE software, the sequence diagrams for the Engineered Safety Features Component Control System (ESF-CCS) of the Nuclear Power Plant are created. Sequence diagrams are chosen because they are a means of representing the systems behavior and the interaction between components. In addition, from these diagrams, the system's functional requirements can be elicited. These diagrams then serve as the baseline of the reverse engineering process and multiple system views are subsequently be created from them, thus speeding up the development process. In addition, the use of MBSE ensures that any additional information obtained from auxiliary sources can then be input into the system model, ensuring data consistency.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.83-85
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• 2003

This paper presents a speed control of permanent magnet synchronous motors (PMSM) using an adaptive integral binary observer without speed and position sensors. In view of composition with a main loop regulator and an auxiliary loop regulator, the binary observer has a property of the chattering alleviation in the constant boundary layer. In order to improve the steady state performance of the binary observer, the proposed adaptive integral binary observer is formed by adding extra integral dynamics to the switching hyperplane equation. The effectiveness of the proposed system is conformed by the experimental results.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 추계학술대회 논문집
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• pp.243-246
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• 2009

기존의 무정전전원장치는 배터리를 보조전원으로 사용하고, 3상 AC/DC 전력 변환 시스템으로 사이리스터의 위상 제어방법을 사용하였다. 하지만 배터리를 보조전원으로 사용함으로써 큰 부피와 수명에 제한을 받게 될 뿐만 아니라, 전원전류의 큰 고조파와 점호각의 증가와 함께 역률이 낮아지는 문제점을 가지고 있다. 따라서 본 논문에서는 이러한 문제점을 해결하기 위해 무정전전원장치의 역률 개선과 전원전류의 고조파 저감을 위해 기존의 AC/DC 정류기 대신에 SVPWM 기법을 적용한 3상 AC/DC Boost 컨버터를 제안한다. 그리고 보조전원으로 쓰이는 기존의 배터리 대신에 친환경 대체에너지원인 연료전지를 무정전전원장치에 적용하여 급격한 부하 변동 시 에너지를 보상하고 기준전압에 맞는 안정된 출력을 갖도록 하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.1094-1097
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• 2001

The control method of Thyristor-controlled Reactor(TCR) is described in this paper for compensating the poor power factor, unbalanced and/or nonlinear load. Also, auxiliary controller such as DC current and power-factor controller is described. The reference current of TCR is calculated from the active and reactive current components for each of the positive and negative sequence components in the load currents. This reactive power control technique was verified by Matlab Simulink and 33Kvar TCR simulator, and will be used in 4.3Mvar TCR system, which will be installed next year at R-Tech Co., located in Po-Hang.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.3-6
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• 2000

In this paper the concept of voltage stability operating limit in optimal power flow problem is described. A methodology of optimal power flow considering voltage stability margin is proposed based on auxiliary constraint to get a secure dispatch solution. The look-ahead margin is used to shift dispatch solutions to the secure direction in proposed framework. The a1gorithm proposed is successfully tested on IEEE 30-bus system.