• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기물성,응용부문
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• pp.209-211
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• 2002

A simple-structured thermal plasma generator for waste gas treatment has been studied. The thermal plasma technology applied to waste treatment has undoubtedly gained high importance owing to its outstanding properties such as flexibility, compact reactor, and clean treatment. Moreover, the thermal plasma generated by ac power has some additional advantages such as simple electrode system and easy maintenance. A prototype 200kW class plasma generator with specifications of 10-30m/sec gas velocity and 3000-5000K temperature on the center just outside of the nozzle has been designed and tested. Case studies on heat transfer, heat flow, velocity distribution, and temperature distribution using a commercial simulation package show lots of flexibility in design. The experimental results from theprototype generator show that the ac thermal plasma is easily controlled by working gas flow once it is ignited. A stabilization condition is discussed with the data from monitoring arc voltage drops with respect to gas flow rate during the test.

• 한국광학회지
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• 제16권4호
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• pp.313-318
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• 2005

순수 차동 위상 변조(NRZ_DPSK) 신호의 눈열림 특성을 이용하여 차동 위상 변조(DPSK) 기반 전송 시스템 수신단에 사용되는 1-비트 지연 마흐젠더 간섭계의 최적 동작점을 자동으로 검색하고, 운용 시 이를 유지하는 능동 안정화 제어 방법을 제안하였다. 이 방법은 추가 부품 없이 밸런스 수신기의 두 출력 DC 전압 차이를 비교하여 제어하므로 경제적이고 구성이 간단하며 입력 파워 의존성이 없다. 실험 결과, 전송율 $10\%$ 정도의 반송 광신호 주파수 변화에 대해서도 안정된 성능을 보였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.352-355
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• 2005

This paper describes an engineering model development of a pulsed plasma thruster, which is capable of an impulse bit of 20uNs and a specific impulse of 800s. The solid fuel which is Teflon allows for a self-contained, inert and stable propellant system. And, the PPT technology makes it possible to consider a revolutionary attitude control system (ACS) concept providing stabilization and pointing accuracies previously obtainable only with reaction wheels, with reduced mass and power requirements.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 C
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• pp.1153-1155
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• 1998

Super-conducting Magnetic Energy Storage(SMES) system is considered to be useful unit to power system stabilizer because of high efficiency and quick response. For effective operating of SMES, we need much studies on accurate modeling and interface characteristics of SMES. In this paper, we propose useful method to SMES, modeling using Artificial Neural Network. Interface technique of proposed model and criterion of stabilization effect is presented. In addition, to demonstrate the validity of proposed method. the simulations were carried out on 3-machine 9-bus system.

• 대한전기학회논문지
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• 제45권2호
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• pp.193-198
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• 1996

Low power superconducting persistent current switch(PCS) for the superconducting magnet systems in the persistent mode was developed and its experimental results were analyzed when the system was charged or discharged. The multifilament NbTi wire with Cu matrix was used for the PCS. The constructed NbTi superconducting switch with superconducting magnet system operated successfully. It also operated on-off switching action with good stabilization. The maximum operating current in persistent mode was 60A (at 1T). In persistent current mode, the decay of the persistent current at 60A was observed. Its decay was 3.55% in 60 min. It is possible to make the persistent current switch with the better decaying of persistent current if some problems for joint resistance are solved.

• 한국인터넷방송통신학회논문지
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• 제19권3호
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• pp.179-184
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• 2019

전기가 부족한 개발도상국 같은 많은 나라에서는 Off Grid 형태의 소형풍력발전이 전력공급 문제를 해결하기 위한 효율적인 핵심 솔루션이다. 몇몇 국가에서는 전력계통의 확장과 전기가 부족한 지역의 감소로 소규모 풍력을 도시의 도로 조명, 모바일 통신 기지국, 양식업 및 해수 담수 등의 분야에 이용하기도 한다. 이런 변화에 따라 소형 풍력 산업 규모는 대규모 풍력보다 큰 잠재력이 기대되고 있다. 소형 풍력발전의 경우 발전기는 가변 속도로 제어되는 특성이 있으며 발전기에서 발생하는 전압 및 전류에는 많은 고조파 성분을 가지고 있다. 이를 해결하기 위해서 본 논문에서는 소형 풍력발전시스템의 직류전원 적용을 위한 운전제어 및 AC/DC 변환 통합장치를 제안하며 기존 AC to DC 컨버터는 단일 스위치를 갖는 3상 승압형 방식의 컨버터로서 인덕터 전류가 불연속모드로 제어되며, 입력전류의 고조파를 제거하여 단위역률을 갖는 특성을 갖는다. 제안된 컨버터는 입력단에 LCL 필터 및 3상 정류 승압형 컨버터, 계통연계를 위한 단상 풀브릿지 형태로 구성되어 있으며 에너지저장시스템(ESS) 기능이 부가된 제어 시스템으로 풍력발전을 이동 평준화 방식에 의해 급변하는 전력에 대해 계통 안정화를 추구할 수 있다.

• 중소기업융합학회논문지
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• 제6권4호
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• pp.93-98
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• 2016

최근 스마트 그리드와 관련된 프로젝트가 선진국을 중심으로 활발하게 연구되고 있다. 특히, 전력 문제의 장기적 안정 대책으로 분산전원이 주목받고 있다. 본 논문에서는 분산형 전원의 출력 예측을 위해서 물리모델과 통계모델을 조합하여 예측 정보 오차율을 비교분석할 수 있는 3차원 기상 수치 모델을 제안한다. 제안 모델은 분산형 전원의 예측정보를 향상시킬 수 있어 안정적인 전력계통 연계를 위한 예측시스템을 가능하다. 성능평가 결과, 제안모델은 발전량 예측 정확도가 4.6% 개선되었고, 온도보정 예측 정확도는 3.5% 향상되었다. 마지막으로 일사량 보정 정확도는 1.1% 향상되었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.1659-1663
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• 1991

A new control design methodology is presented here which is based on a nonlinear time-series reference model. It is indicated by highly nonlinear simulations that such designs successfully stabilize troublesome aircraft maneuvers undergoing large changes in angle of attack as well as large electric power transients due to line faults. In both applications, the nonlinear controller was significantly better than the corresponding linear adaptive controller. For the electric power network, a flexible a.c. transmission system (FACTS) with series capacitor power feedback control is studied. A bilinear auto-regressive moving average (BARMA) reference model is identified from system data and the feedback control manipulated according to a desired reference state. The control is optimized according to a predictive one-step quadratic performance index (J). A similar algorithm is derived for control of rapid changes in aircraft angle of attack over a normally unstable flight regime. In the latter case, however, a generalization of a bilinear time-series model reference includes quadratic and cubic terms in angle of attack. These applications are typical of the numerous plants for which nonlinear adaptive control has the potential to provide significant performance improvements. For aircraft control, significant maneuverability gains can provide safer transportation under large windshear disturbances as well as tactical advantages. For FACTS, there is the potential for significant increase in admissible electric power transmission over available transmission lines along with energy conservation. Electric power systems are inherently nonlinear for significant transient variations from synchronism such as may result for large fault disturbances. In such cases, traditional linear controllers may not stabilize the swing (in rotor angle) without inefficient energy wasting strategies to shed loads, etc. Fortunately, the advent of power electronics (e.g., high-speed thyristors) admits the possibility of adaptive control by means of FACTS. Line admittance manipulation seems to be an effective means to achieve stabilization and high efficiency for such FACTS. This results in parametric (or multiplicative) control of a highly nonlinear plant.

• 전기학회논문지
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• 제66권6호
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• pp.885-891
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• 2017

The energy storage system(ESS) is a core component for exchanging the power system structure of the unidirectional power flow into a bidirectional structure. Its important role has been increasing because it has multiple functions such as output stabilization of new renewable energy, demand management, frequency regulation, etc. However, the performance evaluation technology of ESS in korea is lower than one of advanced countries and the recognition of standardization is also lack compared to advanced countries. Furthermore, in order to more accurately and reliably validate the performance of the ESS in advanced countries, it has been required to perform not only performance testing by H/W devices but also performance verification by S/W tool. Therefore, in order to verify the performance testing of ESS by S/W tool, this paper proposes the modeling method of performance testing devices for MW scaled ESS by using the PSCAD/EMTDC S/W, based on real testing devices in domestic institute. From the simulation results of proposed modeling method, it is confirmed that the proposed modeling method is a useful tool for performance validation of ESS.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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• pp.393-396
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• 1989

This paper deals with the design of the adaptive controller using a decentralized control for Large-Scale system formed of an arbitrary interconnection of subsystem with unknown parameters, non linearity and bounded disturbance. In order to reduce the load and frequency deviations, now decentralized adaptive controllers are developed for stabilization and tracking the parameters. In the simulation studies of the decentralized adaptive control of a two-area interconnected power system, the effectiveness of the proposed adaptive is demonstrated.