• Title/Summary/Keyword: Impedance Parameter

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Equivalent Grid Impedance Estimation Method Using Negative Sequence Current Injection in Three-Phase Grid-connected Inverter (3상 계통 연계형 인버터의 역상분 전류 주입을 이용한 계통 등가 임피던스 추정 기법)

  • Park, Chan-Sol;Song, Seung-Ho;Im, Ji-Hoon
    • The Transactions of the Korean Institute of Power Electronics
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    • v.20 no.6
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    • pp.526-533
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    • 2015
  • A new algorithm is proposed for the estimation of equivalent grid impedance at the point of common coupling of a grid-tie inverter output. The estimated impedance parameter can be used for the improvement of the performance and the stability of the distributed generation system. The estimation error is inevitable in the conventional estimation method because of the axis rotation due to PLL. In the conventional estimation error, the d-q voltage and current are used for the calculation of the impedance with active and reactive current injections. Conversely, in the proposed algorithm, the negative sequence current is injected, and then the negative sequence voltage is measured for the impedance estimation. As the positive and negative sequence current controller is independent and the PLL is based on the positive sequence component only, the estimation of the equivalent impedance can be achieved with high accuracy. Simulation and experimental results are compared to validate the proposed algorithm.

Analysis of the Grounding Impedance of a Ground Rod Considering the Frequency-Dependent Resistivity and Relative Permittivity of Soil (토양의 저항률 및 비유전율의 주파수의존성을 고려한 접지봉의 접지임피던스의 해석)

  • Ahn, Chang-Hwan;Choi, Jong-Hyuk;Lee, Bok-Hee
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.26 no.1
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    • pp.54-60
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    • 2012
  • When the transient current with high frequency components such as lightning surges are injected the grounding electrodes, the performance of grounding electrodes should be evaluated as grounding impedance. It is restricted to analyze the grounding impedance by measurement approach since the grounding impedance is very different with the shape and size of grounding electrodes, resistivity and relative permittivity of soil and the frequency component of the injected current. So a variety of simulation approaches have been developed. Typically, the soil resistivity measured with low frequency and relative permittivity between 1 and 80 are used for simulation of the grounding impedance. However, the resistivity and relative permittivity of soil are changed with frequency of injected current. In this paper, the frequency-dependent resistivity and relative permittivity of soil are measured and these parameters are reflected in the simulation of the grounding impedance of a ground rod. The simulated results are compared with the measured results. As a result, the simulated results with frequency-dependent soil parameters show capacitive aspect like measured results in the frequency of lower than 100[kHz] and they are more consistent with the measured results in wide frequency range.

Method for Adjusting Single Matching Network for High-Power Transfer Efficiency of Wireless Power Transfer System

  • Seo, Dong-Wook;Lee, Jae-Ho;Lee, Hyungsoo
    • ETRI Journal
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    • v.38 no.5
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    • pp.962-971
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    • 2016
  • A wireless power transfer (WPT) system is generally designed with the optimum source and load impedance in order to achieve the maximum power transfer efficiency (PTE) at a specific coupling coefficient. Empirically or intuitively, however, it is well known that a high PTE can be attained by adjusting either the source or load impedance. In this paper, we estimate the maximum achievable PTE of WPT systems with the given load impedance, and propose the condition of source impedance for the maximum PTE. This condition can be reciprocally applied to the load impedance of a WPT system with the given source impedance. First, we review the transducer power gain of a two-port network as the PTE of the WPT system. Next, we derive two candidate conditions, the critical coupling and the optimum conditions, from the transducer power gain. Finally, we compare the two conditions carefully, and the results therefore indicate that the optimum condition is more suitable for a highly efficient WPT system with a given load impedance.

Computation of the Critical Lengths of the Vertical Grounding Electrode in Multi-Layered Soil Structures (다층 대지구조에서 수직 접지전극의 임계길이 산정)

  • Kim, Ki-Bok;Joe, Jeong-Hyeon;Lee, Bok-Hee
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.4
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    • pp.73-80
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    • 2010
  • The grounding impedance is not lowered by expanding the dimension of the grounding electrode, and the length of grounding electrode which shows the minimum value of the grounding impedance for each condition of frequency and soil characteristics is existent, and it is defined as Critical Length. In this paper, a new distributed parameter circuit model considering the condition of the multi-layered soil structures was proposed, and the grounding impedance and critical length of the vertical grounding electrode were analyzed by using the newly proposed simulation model and the MATLAB program. As a consequence, it was found that the effect of the soil structure on the frequency-dependent grounding impedance and critical length of the vertical grounding electrode is significant. It is desirable to consider the soil structure in optimal design of the grounding system.

Impedance Control for Haptic Interface using Parameter Estimation Algorithm

  • Park, Heon;Lee, Sang-Chul;Lee, Soo-Sung;Lee, Jang-Myung
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.119.1-119
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    • 2001
  • Teleoperation enables an operator to manipulate remote objects. One of the main goals in teleoperation researches is to provide the operator with the feeling of the telepresence, being present at the remote site. For these purposes, a master robot must be designed as a bilateral control system that can transmit position/force information to a slave robot and feedback the interaction force. A newly proposed impedance algorithm is applied for the control of a haptic interface that was developed as a master robot. With the movements of the haptic interface for position/for co commands, impedance parameters are varying always. When the impedance parameters between an operator and ...

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RF Loss Minimization Method Using High Impedance Filter for Research (High Impedance Filter를 이용한 RF Loss 최소화 방법에 대한 연구)

  • Wang, Hyun-Chul;Seo, Hwa-Il
    • Journal of the Semiconductor & Display Technology
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    • v.19 no.1
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    • pp.55-60
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    • 2020
  • This study designed High impedance filter to reduce RF loss to heater heating wire and increase RF current flowing to heater ground wire. Effects such as D / R improvement and process reproducibility could be seen. In addition, RF parameter distribution optimization was possible by understanding the RF path of PE-CVD equipment using Plasma and designing filter.

A Study on the Impedance Calculation by using Equivalent Model in Catenary System

  • Kim, Min-Kyu;Kim, Min-Seok;Kim, Dae-Hwan;Lee, Jong-Woo
    • International Journal of Railway
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    • v.3 no.2
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    • pp.46-53
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    • 2010
  • Electric railroad systems consist of rolling stock, track, signal and catenary system. In the catenary system, one of the most important factors is the impedance according to the design and characteristic. Before the catenary system is designed, the impedance should be precedently researched. The railroad catenary system is complex system which is composed by five conductors. The five conductors classify up and down feeders, up and down contact wire group, rail group. Therefore, we should compose the catenary system of the equivalent five-conductors model. In this paper, we suggest a geometrical model and a equivalent conductor model by using geometric mean radius of five conductors in the catenary system. Also, we calculate demanded parameter values in the model. By using those, line constants of five conductors are analyzed by applying the equivalent method called as the condensed joint matrix.

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Optimal Realization of Constnat-Argumet Driving-Point Impedance Using a Nonuiform Distributed RC Element (불균일분포 RC소자에 의한 정편각구동점 임피이던스의 최적실현)

  • 박송배
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.12 no.5
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    • pp.19-24
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    • 1975
  • The problem of realizing a driving-Point impedance, the argument, $\theta$o, of which is as constant as possible over a given frequency reange was considered. An optimal design technique was applied by varying systematically the shape of the distributed element and the parameter values of the lumped elements. As a result it was possible to make the argument over two decades of frequencies within-2.5$^{\circ}$ for $\theta$o=- 30$^{\circ}$ and -60$^{\circ}$ and very flat above a certain frequency for $\theta$o=-45$^{\circ}$.

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Impedance Evaluation Method of UHF RFID Tag Chip for Maximum Read Range (UHF RFID 태그의 최대 인식 거리를 얻기 위한 태그 칩의 임피던스 산출 방법)

  • Sim, Yong-Seog;Yang, Jeen-Mo
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.24 no.12
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    • pp.1148-1157
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    • 2013
  • In a passive UHF RFID system, the impedance matching between tag antenna and chip as well as the protocol parameter settings in a reader plays important role in determination of the maximum read-range. Almost no paper, however, has dealt with the above issues in relation with the maximum read range. In this paper, two known methods (of using the value from data sheets and proprietary RFID tester) and our proposing method in chip impedance evaluation are compared in terms of maximum read range. The read range of tags whose antenna impedance is conjugate matched with the chip impedance obtained from the proposed method is improved maximum 73 % more than that of tags from the other methods.

Power Factor Compensation for Wideband Acoustic Projector Using Measurement Data and ABCD matrix (ABCD 전송 파라메터를 사용한 광대역 음향 발신기의 역률 개선 연구)

  • Lim, Jun-Seok;Pyeon, Yong-Guk
    • 전자공학회논문지 IE
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    • v.48 no.3
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    • pp.10-15
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    • 2011
  • In the case of designing an acoustic transducer for high power application, we usually aim to transfer the source electric energy to the output acoustic energy as large as possible. For this purpose, we should match the impedance of the power amplifier to the impedance combined with the acoustic transducer impedance and the radiation impedance. Especially if we have electrical source with almost zero impedance, we need improve the power factor of the acoustic transducer in the load. In this paper, we propose a broad band impedance matching method by the improvement of power factor, which applies ABCD matrix.