• 전기학회논문지
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• 제66권6호
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• pp.968-974
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• 2017

In this paper, modeling of brushless DC motor (BLDC) driving system for platform screen door control applied fuel cell power generation system has been proposed. At first the system configuration and operational principle of the developed fuel cell simulator has been investigated and the design of BLDC motor driving system is studied and the overall performance and dynamics of the proposed system could be effectively examined by simulation. PSIM simulation program is implemented to verify the performance and compatibility of the fuel cell power generation system and BLDC motor control system modeling.

• ETRI Journal
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• 제41권6호
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• pp.811-819
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• 2019

We propose a substrate with high thermal conductivity, manufactured by the low-temperature co-fired ceramic (LTCC) multilayer circuit process technology, as a new DC/DC converter platform for power electronics applications. We compare the reliability and power conversion efficiency of a converter using the LTCC substrate with the one using a conventional printed circuit board (PCB) substrate, to demonstrate the superior characteristics of the LTCC substrates. The power conversion efficiencies of the LTCC- and PCB-based synchronous buck converters are 95.5% and 94.5%, respectively, while those of nonsynchronous buck converters are 92.5% and 91.3%, respectively, at an output power of 100 W. To verify the reliability of the LTCC-based converter, two types of tests were conducted. Storage temperature tests were conducted at -20 ℃ and 85 ℃ for 100 h each. The variation in efficiency after the tests was less than 0.3%. A working temperature test was conducted for 60 min, and the temperature of the converter was saturated at 58.2 ℃ without a decrease in efficiency. These results demonstrate the applicability of LTCC as a substrate for power conversion systems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.200-202
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• 2004

This paper deals with the real-time monitoring and control system using PC, PDA(Win CE embedded device) and PCS(based BREW platform). The camera attached to the server captures the moving target, and the captured frame of color image is encoded in JPEG for image compression at the server. The client(PC, PDA, PCS) receives the image data from the remote server and the received image is decoded from decompression. We use the TCP/IP protocol to send the image frames. The client can control the position of the camera by sending the control command to the server. Two DC servo motors for the camera are controlled in any directions, up-down and left-right, by the controller which is communicating with the server via the serial communication to get the control command. In this way, on the client we can monitor the moving images at the server and also control the position of the camera.

• 전기학회논문지P
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• 제59권2호
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• pp.158-162
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• 2010

PSD is automatically opened and closed when subway train arrive on the station. This system was designed to control electric automatic system. These doors will provide passenger safety, energy saving and a good environment in subway. The monitoring and control systems of PSD are configured so that they can be operated in automatic mode in connection with ATO through the composite control panel in the station control room. The objective of this paper is to obtain high reliability that is essential for monitoring and control systems of PSD. The power supply is based on protection circuit using DC power bridge from two UPS. Also, stable communication system consists of CAN communication line redundancy and RF cross protection algorithm. Monitoring state display results show the validity of the proposed high reliability monitoring and control systems of PSD.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 추계종합학술대회
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• pp.344-351
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• 2005

본 논문에서는 기존의 위성탑재체 및 지상단말기의 현황을 살펴보고 2008년이후 계속 계획되고 있는 우리나라 정지기상위성 시리즈에 탑재 가능항 DCS와 지상단말기 성능을 연구하고 해양수산활용분야를 제시하고자 한다.

• Journal of Power Electronics
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• 제17권3호
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• pp.733-743
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• 2017

This paper develops a coordinated control strategy of the doubly fed induction generator (DFIG) system based on repetitive control (RC) under generalized harmonic grid voltage conditions. The proposed RC strategy in the rotor side converter (RSC) is capable of ensuring smooth DFIG electromagnetic torque that will enable the possible safe functioning of the mechanical components, such as gear box and bearing. Moreover, the proposed RC strategy in the grid side converter (GSC) aims to achieve sinusoidal overall currents of the DFIG system injected into the network to guarantee satisfactory power quality. The dc-link voltage fluctuation under the proposed control target is theoretically analyzed. Influence of limited converter capacity on the controllable area has also been studied. A laboratory test platform has been constructed, and the experimental results validate the availability of the proposed RC strategy for the DFIG system under generalized harmonic grid voltage conditions.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.858-864
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• 2017

This study aims to restrain free conducting wire-type particles which are commonly and dangerously existing within DC gas-insulated transmission lines. A realistic platform of a coaxial cylindrical electrode was established by using a high-speed camera and a partial discharge (PD) monitor to observe the motion, PD, and breakdown of these particles. The probabilities of standing or bouncing, which can be affected by the length of the particles, were also quantitatively examined. The corona images of the particles were recorded, and particle-triggered PD signals were monitored and extracted. Breakdown images were also obtained. The air-gap breakdown with the particles was subjected to mechanism analysis on the basis of stream theory. Results reveal that the lifting voltage of the wire particles is almost irrelevant to their length but is proportional to the square root of their radius. Short particles correspond to high bouncing probability. The intensity and frequency of PD and the micro-discharge gap increase as the length of the particles increases. The breakdown voltage decreases as the length of the particles decreases.

• Journal of Power Electronics
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• 제13권5호
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• pp.877-883
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• 2013

This paper discussed a transformer-less shunt static synchronous compensator (STATCOM) with consideration of the following aspects: fast compensation of the reactive power, harmonic cancelation and reducing the unbalancing of the 3-phase source side currents. The STATCOM control algorithm is based on the theory of instantaneous reactive power (P-Q theory). A self charging technique is proposed to regulate the dc capacitor voltage at a desired level with the use of a PI controller. In order to regulate the DC link voltage, an off-line Genetic Algorithm (GA) is used to tune the coefficients of the PI controller. This algorithm arranged these coefficients while considering the importance of three factors in the DC link voltage response: overshoot, settling time and rising time. For this investigation, the entire system including the STATCOM, network, harmonics and unbalancing load are simulated in MATLAB/SIMULINK. After that, a 35KVA STATCOM laboratory setup test including two parallel converter modules is designed and the control algorithm is executed on a TMS320F2812 controller platform.

• 기술혁신연구
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• 제17권1호
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• pp.119-148
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• 2009

최근에 서비스산업의 혁신 구조와 유형을 연구하기 위하여 서비스혁신 모형에 대한 논의가 활발하게 진행되고 있다. 본 연구에서는 디지털컨텐츠산업을 분석하여서 서비스 제공자, 컨텐츠 개발자, 사용자 및 네트워크 제공자 사이의 연계성을 연구할 수 있는 혁신시스템의 모형을 제시하였고, 서비스적인 면과 제조업적인 면을 동시에 포함하고 있는 디지털컨텐츠산업 혁신시스템의 특성을 분석하였다. 본 연구에서는 Gallouj and Weinstein(1997) 및 Gallouj(2002)이 제시한 서비스혁신시스템 모형의 바탕 위에서 디지털컨텐츠산업의 특성인 사용자 참가 및 네트워크 외부효과( network externalities) 등을 추가하여서 디지털콘텐츠 서비스 혁신시스템 모형을 구성하였다. 이 모형의 적절성을 검증하기 위하여 우리나라의 온라인게임산업의 혁신 과정 사례를 분석하였고, 사례분석을 통하여 디지털컨텐츠산업의 혁신 유형의 분석, 서비스혁신(service innovation)과 제조혁신(manufacturing innovation)과의 관계, 정부정책의 유효성 등에 대하여 분석하였다. 본 연구에서 도출한 혁신시스템 모형은 디지털컨텐츠산업의 역동성을 이해하는데 다음과 같은 이점을 가지고 있다. 첫째, 컨텐츠 개발자, 플랫폼 제공자 및 네트워크 제공자 사이에 일어나는 제조혁신과 서비스제공자와 사용자 사이에 일어나는 서비스혁신을 분리하였으므로 양 혁신 간의 상호작용을 모형 내에서 분석할 수 있다. 제조혁신과 서비스혁신의 분리를 통하여 디지털컨텐츠산업에 대한 정부의 규제 또는 촉진 정책의 영향을 구체적으로 분석할 수 있다. 둘째, 모형 내에 네트워크의 외부효과를 내생변수화 함으로써 네트워크의 외부효과가 혁신의 선 순환을 일으키는 방식과 구조를 알 수 있는 장점이 있다. 셋째, 서비스혁신의 유형은 제조혁신의 유형과 상이하며 그 효과에 있어서도 큰 차이가 나는 점을 파악할 수 있다. 특히 비 파생적 혁신의 하나인 재조합적 혁신은 제조업에서는 중요하지 않지만, 서비스산업에서는 핵심역량을 구성 한다. 서비스산업의 복제방지 제도가 미비함에도 불구하고 복제가 어려운 이유 중의 하나는 서비스산업이 가지고 있는 독특한 핵심역량 때문이다. 본 연구 결과는 디지털컨텐츠산업의 지속적인 발전의 기초가 되는 여러 유형의 혁신을 촉진하고 유지할 수 있는 정책적 기초를 제공할 수 있는 점에 의의가 있다.

• 한국전자통신학회논문지
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• 제14권1호
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• pp.225-234
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• 2019

마찰 나노 발전을 활용한 TENG(: Triboelectric nanogenerators)는 작은 진동에서 높은 변환 효율과 지속적인 전력을 얻을 수 있는 장점이 있다. 하지만, 마찰 전기 에너지 수집을 위해서는 비선형 에너지 추출 기술이 요구되며, 연결 인터페이스 회로를 통한 동기화 기반의 능동적인 스위치회로가 요구된다. 본 연구는 사람으로의 움직임으로부터 발생한 비선형(non-linear) 에너지를 효율적으로 저장하는 기법을 제시하였다. 또한, 개발된 보드는 서로 다른 방향으로 움직이는 동작으로부터 발생하는 에너지를 효율적으로 수확하고 저장할 수 있다. 본 연구에서 개발된 실리콘기반 압전기반의 TENG 셀과 다중모듈이 연결 가능한 에너지 하베스팅 보드의 측정하였다. 결과적으로, 다중입력 에너지 수집환경에서 안정적인 에너지의 저장 유지를 통해 약 49.2mW/count를 발전하였다.