• 제목/요약/키워드: current

검색결과 77,033건 처리시간 0.078초

아크의 방전에 따른 전기안전에 미치는 영향 (Interruption Controller Design of Arc current With Custom Electric Source)

  • 반기종;임승하;원영진
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2005년도 추계종합학술대회
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    • pp.1283-1286
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    • 2005
  • Arc Fault Current is an electric discharge which is occurred in two opposite electrode. In this paper, arc current control algorithm is designed for the interruption of arc fault current which is occurred in the local electric network. This arc is one of the main causes of electric fire. Arc fault in electrical network has the characteristics of low current, high impedance and high frequency. Conventional arc current controller does not have the arc current interrupt function. Hence, Controller of arc current is designed for the interruption of arc fault current which has the modified arc characteristics.

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실리콘 산화막 전류의 두께 의존성 (Thickness dependence of silicon oxide currents)

  • 강창수
    • 한국결정성장학회지
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    • 제8권3호
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    • pp.411-418
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    • 1998
  • LPCVD 방법으로 실리콘 산화막 두께 10nm에서 80nm인 MOS를 제작하였다. 그리고 스트레스 전계 산화막 전류의 두께 의존성을 조사하였다. 산화막 전류는 스트레스 전류와 전이전류로 구성되어 있음을 보여 주었다. 스트레스 전류는 스트레스 유기 누설전류와 직류전류로 이루어졌으며 산화막을 통하는 트립 어시스트 터널링으로 행해진다. 전이전류는 계면에서 트랩의 터널링 충전과 방전에 의해 이루어진다. 스트레스 전류는 산화막 전류의 두계 한계를 평가하는데 이용되고 전이전류는 기억소자에서 데이터 유지에 사용된다.

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공극형 고온초전도한류기의 특성실험 (Tests of Inductive High-Tc Superconducting Fault Current Limiter with an Air-Gap)

  • 주민석;이찬주;추용;고태국
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1996년도 하계학술대회 논문집 A
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    • pp.181-183
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    • 1996
  • A novel model of an inductive superconducting fault current limiter with an inductive superconducting fault current limiter with the air-gap core was fabricated and tested. If its impedance is not high enough to limit the fault current, then destructive damage occurs in the power system. We attained a magnetic saturation under higher current by an effective air gap introduced in the core. The fault current was successfully limited to two times as much as the nominal current at a 60 Hz source having an effective voltage of 70 V. The fault current flowing under such conditions can be limited to a desired value without any fault current peak within 1/4 cycles.

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Current Memory의 성능 개선을 위한 Dummy Switch의 Width에 관한 연구 (A Study on Width of Dummy Switch for performance improvement in Current Memory)

  • 조하나;홍순양;전성용;김성권
    • 한국지능시스템학회:학술대회논문집
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    • 한국퍼지및지능시스템학회 2007년도 춘계학술대회 학술발표 논문집 제17권 제1호
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    • pp.485-488
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    • 2007
  • 최근 Analog Sampled-Data 신호처리를 위하여 주목되고 있는 SI(Switched-Current) circuit은 저전력 동작을 하는 장점이 있지만, 반면에 SI circuit에서의 기본 회로인 Current Memory는 Charge Injection에 의한 Clock Feedthrough이라는 치명적인 단점을 갖고 있다. 따라서 본 논문에서는 Current Memory의 문제점인 Clock Feedthrough의 일반적인 해결방안으로 Dummy Switch의 연결을 검토하였고, Austria Mikro Systeme(AMS)에서 $0.35{\mu}m$ CMOS process BSIM3 Model로 제작하기 위하여 Current Memory의 Switch MOS와 Dummy Switch MOS의 적절한 Width을 정의하여야 하므로, 그 값을 도출하였다. Simulation 결과, Switch의 Width는 $2{\mu}m$, Dummy Switch의 Width는 $2.35{\mu}m$로 정의될 수 있음을 확인하였다.

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Compensation Strategy to Eliminate the Effect of Current Measurement Offsets in Grid-Connected Inverters

  • Lee, Chang-Hee;Choi, Jong-Woo
    • Journal of Power Electronics
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    • 제14권2호
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    • pp.383-391
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    • 2014
  • For the digital control of systems such as grid-connected inverters, measuring inverter output currents accurately is essential. However, current measurement offsets are inevitably generated by current measurement paths and cause DC current components in real inverter output currents. Real inverter output currents with DC components cause the DC-link capacitor voltage to oscillate at the frequency of a utility voltage. For these reasons, current measurement offsets deteriorate the overall system performance. A compensation strategy to eliminate the effect of current measurement offsets in grid-connected inverters is proposed in this study. The validity of the proposed compensation strategy is verified through simulations and experiments. Results show that the proposed compensation strategy improves the performance of grid-connected inverters.

전류변성기 두 대와 절대 평가 기술을 이용한 2차 전류 범위 확장 (Secondary Current Range Extension of Current Transformers by Using Two Different Current Transformers and Absolute Evaluation Technique)

  • 김윤형;한상길;정재갑;한상옥
    • 전기학회논문지P
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    • 제58권1호
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    • pp.72-78
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    • 2009
  • We have developed a current range extension method to obtain the ratio error and phase displacement of a current transformer (CT) by using absolute evaluation method and two different CTs. The method was applied to CTs under test with the current ratios in the range of 5,000 A / 1 A - 20,000 A / 1 A. The ratio error and phase displacement of the CT under test obtained in this study are consistent with those measured at the national institute in Germany using the same CT under test within an expanded uncertainty (k = 2) in the overall current ratios.

EEG Current Source Imaging using VEP Data Recorded inside a 3.0T MRI Magnet

  • Han Jae Y.;Choi Young H.;Im Chang H.;Kim Tae-S.;Lee Soo Y.
    • 대한의용생체공학회:의공학회지
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    • 제26권2호
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    • pp.95-99
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    • 2005
  • We have performed EEG current source imaging on the cortical surface using visual evoked potentials (VEPs) recorded inside a 3.0 T MRI magnet. In order to remove ballistocardiogram (BCG) artifacts in the VEPs, an improved BCG template subtraction technique is devised. Using the cortically constrained current source imaging technique and pattern-reversal visual stimulations, we have obtained current source maps from 10 subjects. To validate the EEG current source imaging inside the magnet, we have compared the current source maps to the ones obtained outside the magnet. The experimental results demonstrate that there is a strong correspondence between the current source maps, proving that current source imaging is feasible with the evoked potentials recorded inside a 3.0 T MRI magnet.

Analysis on Current Limiting Characteristics According to the Influence of the Magnetic Flux for SFCL with Two Magnetic Paths

  • Ko, Seok-Cheol;Han, Tae-Hee;Lim, Sung-Hun
    • Journal of Electrical Engineering and Technology
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    • 제9권6호
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    • pp.1909-1913
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    • 2014
  • In this study, a superconducting fault current limiter (SFCL) having two magnetic paths was proposed, and its current limiting characteristics were analyzed. For the SFCL to effectively perform the current limiting operation, it must be designed considering the magnetic saturation of the E-I core. Further, the influence of the magnetic flux on its peak current limiting characteristics was investigated. In addition, the magnetic flux curves of the SFCL obtained from the fault current limiting experiments were analyzed, and the subtractive polarity winding case was observed to not only further reduce the saturation potential of the core but also perform the peak current limiting functions well when compared with the additive polarity winding case.

펄스형 방전플라스마 장치에서 current sheath의 속력 (Speed of Current Sheath in Pulsed Discharge Plasma Device)

  • 최운상;최호성
    • 한국안광학회지
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    • 제12권1호
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    • pp.69-74
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    • 2007
  • 펄스형 방전플라스마장치에서 축방향 플라스마 curren sheath의 속력을 측정하였고, snowplow 모델과 비교하였다. Current sheath의 속력은 $10^6cm/s$로 측정되었다. 측정된 속력 중에서 가벼운 기체인 수소와 헬륨은 모델의 이론과 비슷한 결과가 나왔으나 무거운 기체인 아르곤은 이론과 조금 벗어났다. 그 이유는 current sheath의 불안정성 때문으로 추정된다.

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New Driving Method of High Brightness LED Backlight Using Active Current Source

  • Hwang, S.;LEE, J.;Lim, S.;Oh, M.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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    • pp.1642-1645
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    • 2007
  • The brightness of LED changes according to the current flowing through LEDs. The current mirror was used to drive LEDs effectively. The reference current of the current mirror was usually controlled by the resistor but the size of this resistor is very large and this resistor consumes too much power for high power LED backlight driving. The reference current of the current mirror LED driver was controlled by using flyback converter at small size with low power consumption in this paper. The concept of active current source was presented.

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