• 제목/요약/키워드: Fundamental Circuit

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Concept Design for the Intelligent Surveillance System for Urban Transit (도시철도 지능형 종합감시시스템 개념설계)

  • An, Tae-Ki;Shin, Jeong-Ryol;Lee, Woo-Dong;Han, Seok-Yoon
    • Proceedings of the KSR Conference
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    • 2008.06a
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    • pp.653-658
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    • 2008
  • Service areas in the urban transit need to construct the intelligent integrated surveillance system, because they are the public places that many people get together at one time. In past, analogue, closed-circuit televisions and analogue video recorders are used to construct the surveillance system. Now, a lot parts of the analogue systems that depend on the images have been changed to the complicated system, which consists of sensors and images and also, to be digitalized. In past, the surveillance system was used as an inspection devices to examine the spots after happening some events. But, with a high level of the computer and communication technologies, it is possible that the digitalized data leads the intelligence systems to prevent some accidents by using the various analysis techniques. And the data could be used to decide surveillance policies and provide some information on the safety and management policies as well as surveillance policies. In this paper, we define the intelligent surveillance system and suggest the major functions of the system. Also, we suggest the fundamental functions that every part should get and describe the way to develop the system.

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Design and fabrication of an optimized Rogowski coil for plasma current sensing and the operation confidence of Alvand tokamak

  • Eydan, Anna;Shirani, Babak;Sadeghi, Yahya;Asgarian, Mohammad Ali;Noori, Ehsanollah
    • Nuclear Engineering and Technology
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    • v.52 no.11
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    • pp.2535-2542
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    • 2020
  • To understand the fundamental parameters of Alvand tokamak, A Rogowski coil with an active integrator was designed and constructed. Considering the characteristics of the Alvand tokamak, the structural and electrical parameters affecting the sensor function, were designed. Calibration was performed directly in the presence of plasma. The sensor has a high resistance against interference of external magnetic fields. Plasma current was measured in various experiments. Based on the plasma current profile and loop voltage signal, the time evolution of plasma discharge was investigated and plasma behavior was analyzed. Alvand tokamak discharge was divided into several regions that represents different physical phenomena in the plasma. During the plasma discharge time, plasma had significant changes and its characteristic was not uniform. To understand the plasma behavior in each of the phases, the Rogowski sensor should have sufficient time resolution. The Rogowski sensor with a frequency up to 15 kHz was appropriate for this purpose.

Analisys about the Earth Fault Characteristics in the Wireless Power Transmission System of the Electric Vehicle (무선충전 전기자동차 전력공급장치에서의 지락사고 특성 분석)

  • Jung, Jin-Soo;Han, Woon-Ki;Park, Chan-Um;Song, Young-Sang;Lim, Hyun-Sung;Cho, Min-Ho;Lyu, Ji-Yun
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.28 no.12
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    • pp.13-17
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    • 2014
  • In this paper, the risk of electric shock is analyzed through analysis for characterization of potential distribution analysis and ground fault current analysis near the area where there are occurred a ground fault at electric vehicle wireless charging system using 20kHz. Studies for electric vehicle wireless charging system are in the works for development of efficiency increase, pickup shape design and communication module as a fundamental research step. But the research related to electrical safety and is still scarce state so that more studies are necessary to commercialize. As a result of analysis, it is verified that induced voltage is arisen more up to 45V near the a area of accident during ground fault and fault current has been maintained continuously without clearing fault condition by operating characteristics for circuit breaker and inverter.

Design of 60 ㎓ Millimeter-Wave Frequency Doubler using Distributed Structure

  • Park, Won;Lee, Kang-Ho;Kim, Sam-Dong;Park, Hyung-Moo;Rhee, Jin-Koo;Koo, Kyung-Heon
    • Journal of electromagnetic engineering and science
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    • v.4 no.2
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    • pp.87-92
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    • 2004
  • A millimeter-wave distributed frequency doubler has been designed with distributed block and frequency tunable output reflectors. The simulated conversion loss of 9.5 ㏈ to 7.7 ㏈ from 54.6 ㎓ to 62.4 ㎓ output frequencies is achieved with fundamental and third harmonic signal rejections of more than 10 ㏈c. The fabricated chip has the size of 1.2 mm${\times}$1.0 mm. Some measured results of frequency and bias dependent characteristics are presented for the fabricated PHEMT MMIC frequency doubler. The designed doubler has two transistors, and if one of the transistors fails the doubler unit still operates with reduced gain. The failure effect of the PHEMT has been simulated, and compared to the measured data of which one PHEMT is not operating properly.

A Study on Optimization of Electric Power Facilities Applied Matrix System at 25.8kV GIS (25.8kV급 GIS에 Matrix System을 적용한 전력설비 최적화 연구)

  • Lee, Yang-Mi;Nam, Jae-Woo;Kim, Chul-Hwan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.3
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    • pp.507-512
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    • 2017
  • Recently, more electric power facilities have been miniaturized and it is noted that the facilities maintenance will be essential through operation optimization. In this paper we applied and examined the operation optimization of electric power facilities by applying Matrix system which can improve reliability to minimize outage and recover failure rapidly when blackouts happen at 25.8kV Gas Insulated Switchgear(GIS). The fundamental problem for facilities maintenance of GIS can happen due to indeterminable internal state in real time. Matrix optimization organizes action states in all containers which contain pressurized $SF_6$ Gas such as circuit breaker, disconnector switch, bus for utilizing them each area. Then, we connect it with power system to monitor and control internal state remotely in real time, and we can minimize blackout zone or outage. Considering above process, we improved stability of overall facilities.

A Study on the Application Method of Steinberg Fatigue Limit Equation for Electronic Part Life Assessment of Fighter Aircraft Radar (전투기 레이다용 전자부품 수명평가를 위한 Steinberg 피로한계식 적용방안 연구)

  • Kim, Deokjoo;Hah, Seung Ryong;Kang, Minsung;Heo, Jaehun
    • Journal of the Korea Institute of Military Science and Technology
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    • v.23 no.4
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    • pp.319-327
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    • 2020
  • In this study a methodology to evaluate fatigue life of the electronic parts for the fighter radar unit under random vibration loading is presented. To do this, one parameter for the 3-σ RMS quation of Steinberg fatigue model is modified to come up with a printed circuit board(PCB) with multiple electronic parts, while fundamental frequency and dynamic deflection of the PCB are calculated from a MATLAB based finite element computer code. For the RIFA structure selected in this study, the 3-σ RMS fatigue limit displacement is reduced to 0.741 times as much as the Steinberg model. This investigation allows to assess the life of multiple electronic parts mounted on the PCB with reinforced metal cover/body showing non-sinusoidal deflection patterns.

Push-Push Voltage Controlled Dielectric Resonator Oscillator Using a Broadside Coupler

  • Ryu, Keun-Kwan;Kim, Sung-Chan
    • Journal of information and communication convergence engineering
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    • v.13 no.2
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    • pp.139-143
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    • 2015
  • A push-push voltage controlled dielectric resonator oscillator (VCDRO) with a modified frequency tuning structure using broadside couplers is investigated. The push-push VCDRO designed at 16 GHz is manufactured using a low temperature co-fired ceramic (LTCC) technology to reduce the circuit size. The frequency tuning structure using a broadside coupler is embedded in a layer of the A6 substrate by using the LTCC process. Experimental results show that the fundamental and third harmonics are suppressed above 15 dBc and 30 dBc, respectively, and the phase noise of push-push VCDRO is -97.5 dBc/Hz at an offset frequency of 100 kHz from the carrier. The proposed frequency tuning structure has a tuning range of 4.46 MHz over a control voltage of 1-11 V. This push-push VCDRO has a miniature size of 15 mm×15 mm. The proposed design and fabrication techniques for a push-push oscillator seem to be applicable in many space and commercial VCDRO products.

Hybrid Fuzzy PI-Control Scheme for Quasi Multi-Pulse Interline Power Flow Controllers Including the P-Q Decoupling Feature

  • Vural, Ahmet Mete;Bayindir, Kamil Cagatay
    • Journal of Power Electronics
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    • v.12 no.5
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    • pp.787-799
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    • 2012
  • Real and reactive power flows on a transmission line interact inherently. This situation degrades power flow controller performance when independent real and reactive power flow regulation is required. In this study, a quasi multi-pulse interline power flow controller (IPFC), consisting of eight six-pulse voltage source converters (VSC) switched at the fundamental frequency is proposed to control real and reactive power flows dynamically on a transmission line in response to a sequence of set-point changes formed by unit-step reference values. It is shown that the proposed hybrid fuzzy-PI commanded IPFC shows better decoupling performance than the parameter optimized PI controllers with analytically calculated feed-forward gains for decoupling. Comparative simulation studies are carried out on a 4-machine 4-bus test power system through a number of case studies. While only the fuzzy inference of the proposed control scheme has been modeled in MATLAB, the power system, converter power circuit, control and calculation blocks have been simulated in PSCAD/EMTDC by interfacing these two packages on-line.

Isolated Multi-level Inverter Using 3-Phase Transformers (3상 변압기를 이용한 절연형 멀티레벨 인버터)

  • Kim, Tae-Jin;Park, Sung-Jun;Kim, Cheul-U;Song, Sung-Geun
    • The Transactions of the Korean Institute of Power Electronics
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    • v.12 no.2
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    • pp.139-148
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    • 2007
  • In this paper, we proposed the isolated multi-level inverter using 3-phase transformers. It makes possible to use a single DC power source due to employing low frequency transformers. In this inverter, the number of transformer could be reduced comparing with an exiting 3-phase multi-level inverter using single phase transformer. Also, using phase angle control method with switching frequency equal to output fundamental frequency, harmonics component of output voltage and switching losses can be reduced. Finally, we made a prototype inverter to clarify the proposed electric circuit and reasonableness of control signal.

3-Phase Transformer Isolated Multi-level Inverter Using Common Arm (공통암을 이용한 3상 변압기 절연 멀티레벨 인버터)

  • Song, Sung-Geun;Park, Sung-Jun;Kim, Dong-Ok;Lim, Young-Cheol;Kim, Kwang-Heon
    • The Transactions of the Korean Institute of Power Electronics
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    • v.12 no.2
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    • pp.149-156
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    • 2007
  • The number of transformer and the size of transformer in inverter using 3-phase transformer could be reduced compare with a multi-level inverter using single phase transformer. but still the 3-phase transformer inverter needs many switches. In this study, we proposed the isolated multi-level inverter using 3-phase transformers and common arm, in this paper. Also, using phase angle control method with switching frequency equal to output fundamental frequency, harmonics component of output voltage and switching loss can be reduced. Finally, We tested multi-level inverter to clarify electric circuit md reasonableness through Matlab simulation and experiment by using prototype inverter.