• Title/Summary/Keyword: 전류계

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Basin analysis using high-resolution magnetotelluric data (고해상 자기지전류 자료를 이용한 분지해석)

  • Ryang Woo Hun
    • The Korean Journal of Petroleum Geology
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    • v.7 no.1_2 s.8
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    • pp.7-12
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    • 1999
  • A new high-resolution rnagnetotelluric (MT) survey was conducted for pull-apart basin analysis (Cretaceous Eumsung Basin), combined with surface sedimentological results. Two cross-basinal MT profiles represent an asymmetric form with a subbasin in the southeastern part. These basinal architectures are well compatible with paleoflow directions and facies transitions of surface sedimentology. The results also suggest that the basin fills reflect pull-apart opening with rapid subsidence of the central blocks. Combined with the surface sedimentological data on asymmetric lithofacies distribution, facies transitions, and paleoflow directions of the alluvio-lacustrine systems, the MT data help explain basin-fill processes during the basin formation. For petroleum exploration and basin analysis, the high-frequency MT technique can be a useful substitute for the costly burden of a seismic-reflection survey on land.

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Correction on Current Measurement Errors for Accurate Flux Estimation of AC Drives at Low Stator Frequency (저속영역에서 교류전동기의 정확한 자속추정을 위한 전류측정오차 보상)

  • Cho, Kyung-Rae;Seok, Jul-Ki
    • The Transactions of the Korean Institute of Power Electronics
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    • v.12 no.1
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    • pp.65-73
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    • 2007
  • This paper presents an on-line correction method of current measurement errors for a pure-integration-based flux estimation down to 1-Hz stator frequency. An observer-based approach is taken as one possible solution of eliminating the dc offset and the negative sequence component of unbalanced gains in the synchronous coordinate. At the same time, the positive sequence component estimation is performed by creating an error signal between a motor model reference and an estimated q-axis rotor flux established by a permanent magnet (PM) in the synchronous coordinate. The compensator utilizes a PI controller that controls the error signal to zero. The proposed technique further contains a residual error compensator to completely eliminate miscellaneous disturbances in the estimated flux. The developed algorithm has been implemented on a 1.1-kW permanent magnet synchronous motor (PMSM) drive to confirm the effectiveness of the proposed scheme.

복합센서를 이용한 공구이상검출

  • 이재종;송준엽;박화영
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.10a
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    • pp.239-243
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    • 2001
  • 본 연구에서는 절삭중 공구파손을 실시간으로 검출할 수있는 시스템을 구성하기 위한 일환으로 일차로 AE(acoustic emission)센서를 사용하여 mechanism의 특성과 공구파손에 따른 주파수 특성을 해석했고, 차후 연구로서 AE센서가 아닌 가속도센서와 전류센서 및 공작기계의 절삭동력계를 이용한 복합계측시 스템을 구성하여 절삭특성 및 공구파손이 발생할 때의 신호특성을 해석했다.

현대제어이론을 이용한 유도전동기 제어

  • 이동춘;지준근
    • 전기의세계
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    • v.43 no.2
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    • pp.20-29
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    • 1994
  • 본고에서는 다변수 상태궤환을 이용한 유도전동기의 전류제어, 확장칼만필터(Extened Kalman filter)를 이용한 유도전동기의 속도추정, 칼만필터와 최적제어를 이용한 2관성계 유도전동기 시스템의 축진동 억제를 위한 속도제어 등 현대제어이론을 산업용 유도전동기 제어에 적용한 예에 대해 기술한다.

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A Design of Fire-Command Synchronous Satellite Pyrotechnic Circuit (점화 명령에 동조된 인공위성 파이로테크닉 회로 설계)

  • Koo, Ja Chun;Ra, Sung Woong
    • Journal of Korea Society of Industrial Information Systems
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    • v.18 no.5
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    • pp.81-92
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    • 2013
  • The satellite includes many release mechanisms such as solar array deployment, antenna deployment, cover to protect contamination in scientific equipment, pyro value of the propulsion subsytem, and bypass device in Li-Ion cell module. A drive the initiators is a critical to the successful mission because the initiators of release mechanism driving by the pyrotechnic circuit is operated in single short. The pyrotechnic circuit has to provide switching network for safety. A typical switching network has defect consisting of high current rating fire switch to handle switching transient current during fire the initiator. The pyrotechnic circuit is required some form of power conditioning to reduce the peak power demanded from the bus if the initiators are to be fired from the main bus. This paper design a pyrotechnic circuit synchronized to the fire-command to activate the fire switch to overcome use high current rating fire switch to handle switching transient current during fire the initiator. The pyrotechnic circuit provides a current limited widow pulse for fire current synchronized to the fire-command to insure that fire switch will only carry the current but never switch it. The current limited widow pulse for fire current can be possible to use low current rating and light mass switch in switching network. The current limit function in the pyrotechnic circuit reduces supply voltage to initiator and provides the effect of power conditioning function to reduce peak bus power. The pyrotechnic circuit to apply satellite development on geostationary orbit is verified the function by test in development model.

Properties and Performance of Electroactive Acrylic Copolymer-Platinum Composite Modified with Sodium Montrnorillonite (Sodium Montrnorillonite로 개질한 아크릴계 IPMC의 물성과 전기 구동 특성)

  • Jeong, Han-Mo;Kim, Byung-Chon;La, Young-Soo
    • Polymer(Korea)
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    • v.29 no.4
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    • pp.380-384
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    • 2005
  • Fluoroalkyl methacrylate and acrylic acid were bulk radical copolymerized in the presence of pure sodium montmorillonite or macromer intercalated sodium montmorilonite to get a fluorinated acrylic ionomer/sodium montmorillonite composite, and their physical properties, such as X-ray diffraction pattern, tensile properties, and water uptake, were examined. These composites were used to preparean ionic acrylic polymer-platinum composite (IPMC). The current and deformation responses of these IPMCs by external voltage applied across the platinum electrodes deposited on both sides of IPMC showed that the cation migration from anode to cathode was suppressed in the presence of sodium montmorillonite, causing reduced current and deformation.

Scaling theory to minimize the roll-off of threshold voltage for nano scale MOSFET (나노 구조 MOSFET의 문턱전압 변화를 최소화하기 위한 스케일링 이론)

  • 김영동;김재홍;정학기
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2002.11a
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    • pp.494-497
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    • 2002
  • In this paper, we have presented the simulation results about threshold voltage of nano scale lightly doped drain (LDD) MOSFET with halo doping profile. Device size is scaled down from 100nm to 40nm using generalized scaling. We have investigated the threshold voltage for constant field scaling and constant voltage scaling using the Van Dort Quantum Correction Model(QM) and direct tunneling current for each gate oxide thickness. We know that threshold voltage is decreasing in the constant field scaling and increasing in the constant voltage scaling when gate length is reducing, and direct tunneling current is increasing when gate oxide thickness is reducing. To minimize the roll-off characteristics for threshold voltage of MOSFET with decreasing channel length, we know u value must be nearly 1 in the generalized scaling.

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