• Journal of Electrical Engineering and Technology
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• 제8권4호
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• pp.760-765
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• 2013

An Interline Power Flow Controller (IPFC) is a converter based controller which compensates and balance the power flow among multi-lines within the same corridor of the multi-line subsystem. The Interline Power Flow Controller consists of a voltage source converter based Flexible AC Transmission System (FACTS) controller for series compensation. The reactive voltage injected by individual Voltage Source Converter (VSC) can be controlled to regulate active power flow in the respective line in which one VSC regulates the DC voltage, the other one controls the reactive power flows in the lines by injecting series active voltage. In this paper, a circuit model for IPFC is developed and simulation of interline power flow controller is done using the proposed circuit model. Simulation is done using MATLAB Simulink and PSPICE. The results obtained by MATLAB are compared with the results obtained by PSPICE and compared with theoretical values.

• 한국정보통신학회논문지
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• 제6권1호
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• pp.25-29
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• 2002

High speed 신호처리는 통신분야, SC circuit, HDTV, ISDN 등에서 관심이 더욱 승가하고 있으며, high speed 신호처리를 위한 많은 방법들이 있다. 본 논문에서는 CMOS 공정에서 고주파 Op-amp의 실현을 의한 설계를 기술하였다. 아날로그 집적회로를 기초로 하는 high speed op-amp의 기능을 제한하는 요소 중 한가지는 유효 주파수 범위이다. 본 논문에서는 $C_{L}$ =2pF에서 단위이득 주파수가 170MHz인 향상된 대역폭적을 가지는 CMOS op-amp 구조를 계발한다. 공정은 1.2$\mu$디자인 룰을 따른다. 본 논문에서 제시한 CMOS op-amp 고주파 SC filter에서 요구하는 큰 커패시터 부하에서의 넓고 안정된 대역폭을 얻기에 매우 적합하다.

• 조명전기설비학회논문지
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• 제20권7호
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• pp.38-45
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• 2006

초전도전류제한기(SFCL)는 전력계통내 적용시 계통보호를 보다 향상시킬 수 있는 방안으로써 수초이내에 신속하게 사고전류를 제한한다. 이러한 SFCL중 자속구속형 전류제한기의 설계구조는 자속구속리액터인 하나의 철심에 1차측과 2차측 코일이 병렬로 결선되어 있다. 또한 전류제한소자인 YBCO박막과 2차측 코일을 직렬로 결선하여 설치장소의 조건에 따라 인덕턴스와 2차측 코일의 극성방향으로 과도전류 크기를 조절할 수 있다. 이러한 동작특성은 철심을 자속매개체로 적용되기 때문에 철심조건에 따른 성능평가실험은 필수적이다. 가극결선에서 전원전압을 200[Vrms] 인가시 피크전류는 폐루프가 30.71[A], 개루프가 32.01[A]까지 상승됨에 따라 초기과도 응답특성은 폐루프가 유리하였다. 하지만, 소자에 발생되는 전압이 폐루프가 220.14[V], 개루프가 142.73[V]까지 상승함에 따라, 폐루프 철심구조시 전류제한소자의 부담이 가중됨을 알 수 있었다. 결과적으로 자속구속형 SFCL의 전력계통내 적용 시 각각의 철심구조에 따른 다양한 운전특성을 적절히 설계시 장점을 극대화 할 수 있을 것이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.185-187
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• 2000

Fault current is flowed into 154/23kV M. Tr when line-to-ground fault occurs in power system. NGR(Neutral Grounded Reactor) is set up in order to prevent M.Tr fault by limiting magnitude of fault currents. Here, disconnection of NGR causes voltage increase by L-C resonance and line-to-ground fault in an unearthed system results in voltage increase at healthy phases. So Over Voltage Ground Relay(OVGR) is used for tripping M.Tr. Also, buses at second phases of M.Trs are all connected with section circuit breakers closed for the purpose of parallel operation and load shedding. In case of speciality buses are comprised of power cable in part for GIS connection. When no-load charged cable or bus is open by a section CB, unbalanced voltage charged on the bus is induced. Also discrepant opening time for circuit breakers on different phases gives rise to unbalanced zero sequence voltage. It was observed that this zero sequence voltage detected in the 22.9kV P.T (Potential Transformer for bus) mal-operated 59GT and tripped M.Tr. The zero sequence voltage of which vanishing time is longer than relay operating time came out by EMTDC simulation. Also, it was shown that the voltage waves of actual test are similar to those of simulation. On the basis of above results, R-C circuit complement on the relay without any effect on a power system made operating time of the relay longer than vanishing time of distorted waves. Consequently, operating time of the relay was delayed and magnitude of distorted waves was decreased by increasing time constant of the relay.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제3B권1호
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• pp.1-9
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• 2003

This paper deals with the nodal admittance approach steady-state frequency domain analysis of the three-phase self-excited induction generator (SEIG) driven by the variable speed prime mover as the wind turbine. The steady-state performance analysis of this power conditioner designed for the renewable energy is based on the principle of equating the input mechanical power of the three-phase SEIG to the output mechanical power of the variable speed prime mover mentioned above. Us-ing the approximate frequency domain based equivalent circuit of the three-phase SEIG. The main features of the present algorithm of the steady-state performance analysis of the three-phase SEIG treated here are that the variable speed prime mover characteristics are included in the approximate equivalent circuit of the three-phase SEIG under the condition of the speed changes of the prime mover without complex computations processes. Furthermore, a feedback closed-loop voltage regulation of the three-phase SEIG as a power conditioner which is driven by variable speed prime movers such as the wind turbine(WT) employing the static VAR compensator(SVC) circuit composed of the thyristor phase controlled reactor(TCR) and the thyristor switched capacitor(TSC) controlled by the PI controller is designed and considered for wind-turbine driving power conditioner.

• 한국전자파학회논문지
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• 제15권12호
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• pp.1161-1167
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• 2004

기존의 PLL(phase locked loop)은 폐루프 구조이므로 주파수 스위칭 속도가 낮은 단점을 갖는다. 이를 개선하기 위해서 개루프 구조를 혼합한 Digital Hybrid PLL 구조를 연구하였다. 또한 이 구조는 빠른 주파수 스위칭 속도로 동작할 수 있지만, VCO의 전압대 주파수 전달특성을 ROM 형태로 구현하는 DLT(digital look-up table)이 사용되어야 하므로 회로소자가 많아지고 소비전력이 증가된다. 그러므로, 본 논문에서는 복잡한 DLT의 구조를 간단한 Digital logic 회로로 대체시킨 새로운 구조를 제안하였다. 또한 주파수 합성때마다 타이밍 동기화를 이루는 회로를 설계하여 합성기의 항상성을 확보하였으며 DLT를 사용하는 방식과 비교하여 회로소자를 약 $28\%$정도 줄일 수 있다. 고속 스위칭 동작 특성과 주파수 합성을 시뮬레이션과 실제 회로 구현으로 확인하였다.

• 한국물환경학회지
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• 제28권6호
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• pp.917-922
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• 2012

In order to improve applicability of a microbial fuel cell the laboratory-scaled study has been performed by adopting an air-cathode MFC system with high concentrated anaerobic slugies in this study. The concentrations of microbes are grouped into three types, Type A (TS 1.7%), Type B (TS 1.1%) and Type C (TS 0.51%). The open circuit voltage $(V_{oc})$ characteristics showed that the medium microbes concentration of 1.10% (Type B) kept a constant voltage of 1.0 V for 150 hours, which showed the longest time among three types (Type A and Type C). The discharge charge curves for a closed circuit with $500 \Omega$ also showed that Type B generated a stable discharge voltage of 0.8 V for a longer time as in the open circuit voltage case. This could be explained by the relatively large amount of the attached microbes. Under the $V_{oc}$condition the COD removal efficiency of Type B was found to be low for a long time, but those of Type A and C were found to be high for a short period of time. Therefore, the suspended microbes could decrease the coulombic efficiency. It was concluded that the high $V_{oc}$ was caused by low COD and the $V_{oc}$ became low after the COD removal. The COD reduction resulted in an unstable and low working voltage. From the polarization characteristics Type A was found to show the highest power density of $193\;mW/m^2$ with a fill factor of 0.127 due to the relatively high remaining COD even after the MFC reaction.

• 한국정보전자통신기술학회논문지
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• 제11권6호
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• pp.664-670
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• 2018

현대 사회는 감시의 눈이라 하는 CCTV가 일상생활 속에서 다양한 방법으로 영상데이터를 수집하기 위해 사용되고 있다. 치안 및 감시, 방범용으로 CCTV를 활용할 뿐만 아니라 자동차에 블랙박스 등 많은 분야에서 활용되고 있다. 본 논문에서는 STM32F407 ARM 칩을 기반으로 다양한 분야에 응용할 수 있는 카메라 시스템을 개발하기 위해 연구를 진행하였다. 카메라 시스템 개발을 위해 솔리드 웍스 환경에서 전체적인 구조를 3D를 기반으로 카메라 시스템을 모델링을 진행하였다. PCB 보드 설계는 카메라 시스템 모델링 파일에서 PCB 부품을 iges 파일로 추출하여 Altium Designer 툴에서 3D와 2D 보드로 변환하여 PCB 설계 진행함으로써 완성도 높은 조립성을 가질 수 있도록 진행하였다. 카메라 시스템 회로 및 PCB를 설계한 후, TRM(Thermal Risk Management) 툴을 활용해서 보드에서 발생하는 발열 시뮬레이션을 진행을 통해 대처할 수 있도록 함으로써 안정적인 시스템 구현에 관한 연구를 진행하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1716-1721
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• 2011

The Public Address and Passenger Information System of Rolling Stock should be able to perform automatic announcements in connection with TCMS(Train Control and Monitoring System), common announcements and emergency announcements for safe operation and the passengers. CCTV(Closed Circuit Television) System also should be able to watch passenger compartment for safety. Those equipments are very important thing for train service and safety. but the installation of equipment is restricted by space, weight, modulation. therefore, Passenger Information Intergrated System(PIIS) is required to consider economical efficiency, technical trend, expansion and space insufficiency. and system based on IP network has to be considered as new PIIS. so PIIS could meet economical efficiency and expansion. and it could go further and share network with TCMS and others.

• Journal of Power Electronics
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• 제14권1호
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• pp.40-47
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• 2014

An average current mode control scheme that consistently offers good dynamic performance for LLC series resonant DC-to-DC converters irrespective of the changes in the operational conditions is presented in this paper. The proposed control scheme employs current feedback from the resonant tank circuit through an integrator-type compensation amplifier to improve the dynamic performance and enhance the noise immunity and reliability of the feedback controller. Design guidelines are provided for both current feedback and voltage feedback compensation. The performance of the new control scheme is demonstrated through an experimental 150 W converter operating with 340 V to 390 V input voltage to provide a 24 V output voltage.