• 제목/요약/키워드: impedance

검색결과 6,452건 처리시간 0.039초

Impedance Matching Characteristic Research Utilizing L-type Matching Network

  • Jun Gyu Ha;Bo Keun Kim;Dae Sik Junn
    • 반도체디스플레이기술학회지
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    • 제22권2호
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    • pp.64-71
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    • 2023
  • If an impedance mismatch occurs between the source and load in a Radio Frequency transmission system, reflected power is generated. This results in incomplete power transmission and the generation of Reflected Power, which returns to the Radio Frequency generator. To minimize this Reflected Power, Impedance matching is performed. Fast and efficient Impedance matching, along with converging reflected power towards zero, is advantageous for achieving desired plasma characteristics in semiconductor processes. This paper explores Impedance matching by adjusting the Vacuum Variable Capacitor of an L-type Matching Module based on the trends observed in the voltage of the Phase Sensor and Electromotive Force voltage. After assessing the impedance matching characteristics, the findings are described.

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Hybrid vibration-impedance monitoring in prestressed concrete structure with local strand breakage

  • Dang, Ngoc-Loi;Pham, Quang-Quang;Kim, Jeong-Tae
    • Smart Structures and Systems
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    • 제30권5호
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    • pp.463-477
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    • 2022
  • In this paper, a hybrid vibration-impedance-based damage monitoring approach is experimentally evaluated for prestressed concrete (PSC) structures with local strand breakage. Firstly, the hybrid monitoring scheme is designed to alert damage occurrence from changes in vibration characteristics and to localize strand breakage from changes in impedance signatures. Secondly, a full-scale PSC anchorage is experimented to measure global vibration responses and local impedance responses under a sequence of simulated strand-breakage events. Finally, the measured data are analyzed using the hybrid monitoring framework. The change of structural condition (i.e., damage extent) induced by the local strand breakage is estimated by changes in a few natural frequencies obtained from a few accelerometers in the structure. The damaged strand is locally identified by tomography analysis of impedance features measured via an array of PZT (lead-zirconate-titanate) sensors mounted on the anchorage. Experimental results demonstrate that the strand breakage in the PSC structure can be accurately assessed by using the combined vibration and impedance features.

An Islanding Microgrid Power Sharing Approach Using Adaptive Virtual Impedance control scheme

  • Hoang, Van-Tuan;Lee, Hong-Hee
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2016년도 전력전자학술대회 논문집
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    • pp.315-316
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    • 2016
  • This paper proposes an enhanced distributed generation (DG) unit with an adaptive virtual impedance control approachin order to address the inaccurate reactive power sharing problems. The proposed method can adaptively regulate the DG unit thanks to the equivalent impedance, andthe effect of the mismatch in feeder impedance is compensatedto share the reactive power accurately.The proposed control strategy can be implemented directly without any requirement of pre-knowledge of the feeder impedances. Simulations are performed to validate the effectiveness of the proposed control approach.

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국내환경을 고려한 loop impedance 특성 분석 (Analysis of loop impedance characteristic based on korea internal electrical environment)

  • 정진수;한운기;김오환;안재민;이승재
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2009년도 제40회 하계학술대회
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    • pp.2174_2175
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    • 2009
  • This Paper present about loop impedance characteristic based on korea internal electrical environment. Analysis parameters were touch voltage, electrical shock current and human body resistance. Result, For protect of electrical shock must measuring of loop impedance. And current capacity & loop impedance are must important parameters.

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지수선로의 도식해법

  • 박송배
    • 전기의세계
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    • 제9권
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    • pp.18-22
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    • 1962
  • 지수선로는 특히 microwave공학에서 Impedance 변환용으로 널리 사용되고 있으나 그 Impedance 함수 또는 반사계수의 표시식의 복잡성으로 인하여 이 선로의 특성연구, 설계에 있어서 적지 않은 계산의 곤란이 따른다. 따라서 이의 도식해법이 환영된다. 본논문에서 우리는 지수선로의 Impedance함수를 일차변환하면 보통의 균일선로에 대한 것과 유사한 표시식이 얻어짐에 착안하여 복소수의 일차변환을 대표하는 W-평면과 Smith chart 또는 직교 Impedance diagram을 병용하던지 W-평면을 직교 Impedance diagram에 중첩시키던지 또는 Smith chart의 constant-r constant-x도의 label를 고쳐서 사용하던지 하여 지수선로의 문제를 도식으로 해결하는 방법을 모색하였다. 또 같은 착안으로부터 지수선로의 집중정수 등가회로가 흥미있게 구해짐을 부수적으로 지적하였다.

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Impedance Characteristics of Oxide Layers on Aluminium

  • 오한준;장경욱;치충수
    • Bulletin of the Korean Chemical Society
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    • 제20권11호
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    • pp.1340-1344
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    • 1999
  • The electrochemical behavior of oxide layers on aluminium was studied using electrochemical impedance spectroscopy. Impedance spectra were taken at a compact and a porous oxide layer of Al. The anodic films on Al have a variable stoichiometry with gradual reduction of oxygen deficiency towards the oxide-electrolyte interface. Thus, the interpretation of impedance spectra for oxide layers is complicated, with the impedance of surface layers differing from those of ideal capacitors. This layer behavior with conductance gradients was caused by an inhomogeneous dielectric. The frequency response cannot be described by a single RC element. The oxide layers of Al are properly described by the Young model of dielectric constant with a vertical decay of conductivity.

병렬로 시공된 수직 접지전극의 합성접지임피던스의 주파수의존성 분석 (An Analysis of the Frequency-Dependent Resultant Ground Impedance of Vertical Ground Electrodes Installed in Parallel)

  • 이복희;조성철;성창훈
    • 조명전기설비학회논문지
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    • 제26권2호
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    • pp.99-105
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    • 2012
  • This paper deals with the experimental results of the frequency-dependent resultant ground impedance of vertical ground electrodes installed with a regular n-polygon. In order to propose an effective method of installing the vertically-driven multiple ground electrodes used to obtain the low ground impedance, the resultant ground impedance of ground electrodes installed with a regular n-polygon were measured as functions of the number of ground electrodes and the frequency of test currents and the results were discussed based on the potential interferences among ground electrodes. As a consequence, the effect of potential interference on the resultant ground impedance of vertical ground electrodes is frequency-dependent and it is significant in the low frequency of a few hundreds [Hz]. The resultant ground impedance of multiple vertical ground electrodes is not decreased in linearly proportion to the number of ground electrodes due to the overlapped potential interferences. Also the distributed-parameter circuit model considering the potential interference, the frequency-dependent relative permittivity and resistivity of soil was proposed. The simulated results of the frequency-dependent resultant ground impedance of multiple vertical ground electrodes are in good agreement with the measured data.

트란지스터 발진기의 발진영역과 부저항의 변화에 관한 연구 (A Study on the Oscillation Region and the Variation of Negative Resistance in Transistor Oscillators)

  • 이종각
    • 대한전자공학회논문지
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    • 제8권3호
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    • pp.15-26
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    • 1971
  • 본논문은 트란지스터발진기의 발진영역과 부저항의 변화에 대하여 하나의 새로운 방법을 써서 고찰한 것이다. 트란지스터귀환발진기의 발진영역을, 귀환소자임피이던스의 복소평면상에 나타내면 원이 된다. 그리고, 귀환소자임퍼이던스의 저항분을 일정하게 하고, 리액턴스분을 변화시키거나, 혹은 이와 반대로 리액틴스분을 일정하게하고, 저항분을 변화시킬 때, 출력콘덕턴스가 극소로 되는 점의 궤적은 쌍곡선이 된다. 트란지스터수정발진기에서는, 발진영역은 부하임퍼이던스의 복소평면상에서, 입력임피이던스의 실수부 및 허수부를 0이 되게 하는, 두개의 원에 의하여 정해진다. 그리고, 부하임피이던스의 저항분을 일정하게 하고 리액턴스분을 변화시키거나, 혹은 반대로 리액턴스분을 일정하게 하고 저항분을 변화시킬 때, 입력저항을 극대 또는 극소로 되게 한는 점의 궤적은, 네 개의 직선이 된다.

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인식거리 향상을 위한 UHF 대역 RFID 태그 임피던스 정합 설계 (Impedance Tuning and Matching Characteristics of UHF RFID Tag for Increased Reading Range)

  • 이종욱;권홍일;이범선
    • 한국전자파학회:학술대회논문집
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    • 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
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    • pp.279-284
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    • 2005
  • We investigated the impedance matching characteristics of UHF-band RFID tag antenna and tag chip for increased reading range. A voltage multiplier designed using 0.4 $\mu$m zero-$V_T$ MOSFET showed that DC output voltage of about 2 V can be obtained using standard CMOS process. The input impedance of the voltage multiplier was examined to achieve impedance matching to the RFID tag antenna using analytical and numerical approaches. The input impedance of the voltage multiplier could be varied in a wide range by selecting the size of MOSFET and the number of multiplying stages, and thus can be impedance matched to a tag antenna in presence of other tag circuit blocks. A meander line inductively-coupled RFID tag antenna operating at UHF band also shows the feasibility of impedance matching to tile RFID tag chip.

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Novel State-of-Charge Estimation Method for Lithium Polymer Batteries Using Electrochemical Impedance Spectroscopy

  • Lee, Jong-Hak;Choi, Woo-Jin
    • Journal of Power Electronics
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    • 제11권2호
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    • pp.237-243
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    • 2011
  • Lithium batteries are widely used in mobile electronic devices due to their higher voltage and energy density, lighter weight and longer life cycle when compared to other secondary batteries. In particular, a high demand for lithium batteries is expected for electric cars. In the case of the lithium batteries used in electric cars, driving distance must be calculated accurately and discharging should not be done below a level that makes it impossible to crank. Therefore, accurate information on the state-of-charge (SOC) becomes an essential element for reliable driving. In this paper, a novel method for estimating the SOC of lithium polymer batteries using AC impedance is proposed. In the proposed method, the parameters are extracted by fitting the measured impedance spectrum on an equivalent impedance model and the variation in the parameter values at each SOC is used to estimate the SOC. Also to shorten the long length of time required for the measurement of the impedance spectrum, a novel method is proposed that can extract the equivalent impedance model parameters of lithium polymer batteries with the impedance measured at only two specific frequencies. Experiments are conducted on lithium polymer batteries, with similar capacities, made by different manufacturers to prove the validity of the proposed method.