• 한국초전도ㆍ저온공학회논문지
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• 제25권3호
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• pp.38-42
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• 2023

The evaluation of no-insulation (NI) high-temperature superconducting (HTS) typically uses the lumped equivalent circuit (LEC) model. Constant parameters in the NI HTS LEC model accurately predict voltage and central magnetic field at currents below the critical current. However, it is difficult to find constant circuit parameters that simultaneously satisfy the measured voltage and magnetic field under overcurrent conditions. Recent research highlights changes in contact resistance during transient conditions, which may impact power loss estimation in NI HTS coils. Therefore, we confirm the influence of contact resistance changes on loss calculation in the transient state for NI HTS coil. To achieve this, we introduce a measurement data analysis method based on the LEC model and compare it with the LEC model using constant circuit parameters.

• 조명전기설비학회논문지
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• 제18권4호
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• pp.60-67
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• 2004

비선형 부하의 증가로 3상 4선식 배전계통을 채용하는 중성선에는 많은 중성선 고조파 전류가 관측되고 있다. 또한 접지 임피던스는 고주파가 있는 중성선 전류에 영향 끼친다고 알려져 있다. 현장에서 실측한 고조파 전압과 전류, 그리고 대지 고유 저항률과 접지 저항을 토대로 고조파 해석용 등가 회로를 구성하였다. MATLAB과 CDEGS 프로그램으로 시뮬레이션 하여 수치와 파형으로 적절한 결과를 도출하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.103-106
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• 2004

We have studied a conduction mechanism and equivalent circuit analysis in $Alq_3$ based Organic Light Emitting Diode. The conduction mechanism in organic light emitting diode can be classified into three regions; ohmic region, space-charge-limited current (SCLC) region and trap-charge-limited current (TCLC) region depending on the region of applied voltage. Equivalent circuit model of organic light emitting diode can be established using a parallel combination of resistance $R_p$ and capacitance $C_p$ with a small series resistance $R_s$.

• 대한전자공학회논문지SD
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• 제41권3호
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• pp.45-54
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• 2004

릿지 형태 CPW 진행파형 전계 흡수 광 변조기와 광 검출기의 구조에 있어서 마이크로파의 특성은 도파관을 형성하는 진성 영역의 폭, 두께, 신호전극과 접지 전극사이의 거리의 영향을 받게 된다. 이러한 요소들은 소자에 존재하는 캐패시턴스(C)와 인덕턴스(L)의 크기를 변화시키게 되며 마이크로파의 유효 굴절률과 특성 임피던스를 결정하게 된다. 하지만 기존의 논문들은 전계와 자계의 분포에 따라 마이크로스트립과 CPW로 각각 근사화하여 해석했다. 본 논문에서는 FDTD를 이용해 릿지형태 CPW 진행파형 구조의 마이크로파 특성을 분석하고 C와 L의 정량적인 값을 구했으며 이를 등가회로의 회로 소자로써 적용 시켰다. 등가회로에서 구해진 마이크로파의 특성은 FDTD 결과와 거의 일치함을 보였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1471-1473
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• 2000

In this study capacitance and dielectric loss factor were measured with low-voltage signal and the simulation of equivalent circuits for the data were conducted. As the result it was showed that the equivalent circuit model considered the gram-boundary structure with semiconducting layer, dielectric layer and depletion layer was well approximated with the observed data. Various parameters were determined by a optimum curve-fitting method and could be used to analyze the varistor-voltages and the nonlinear coefficient of varistors. It also seems that the proposed equivalent circuit model will be adopted for other BL type varistors.

• ETRI Journal
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• 제27권5호
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• pp.628-634
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• 2005

From AC analysis results utilizing a 2-dimensional device simulator, we extracted an AC-equivalent circuit of a grounded-gate NMOS (ggNMOS) electrostatic discharge (ESD) protection device. The extracted equivalent circuit is utilized to analyze the effects of the parasitics in a ggNMOS protection device on the characteristics of a low noise amplifier (LNA). We have shown that the effects of the parasitics can appear exaggerated for an impedance matching aspect and that the noise contribution of the parasitic resistances cannot be counted if the ggNMOS protection device is modeled by a single capacitor, as in prior publications. We have confirmed that the major changes in the characteristics of an LNA when connecting an NMOS protection device at the input are reduction of the power gain and degradation of the noise performance. We have also shown that the performance degradation worsens as the substrate resistance is reduced, which could not be detected if a single capacitor model is used.

• Journal of Power Electronics
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• 제17권2호
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• pp.422-431
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• 2017

The equivalent circuit of a three-leg, four-wire voltage source converter (VSC) is derived using switching functions. Simulations and experiments are conducted (i) to investigate the effects of the zero sequence on VSCs when a three-phase imbalance exists and (ii) to use the consistency of simulations and laboratory experiments to validate the equivalent circuit. The impact of a three-phase imbalance on the VSC has yet to be fully investigated because of the lack of an equivalent circuit to show rigorously how the zero sequence currents flow through the VSC.

• 한국정밀공학회지
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• 제22권4호
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• pp.99-106
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• 2005

In this study, the electromagnetic characteristics of a flat-type two-dimensional proportional solenoid were analyzed by the magnetic reluctance method. The equivalent magnetic circuit equation for the solenoid was derived by modeling the reluctance of air gaps and magnetic structural components such as pole core, armature and yoke. It was solved iteratively because of the nonlinear magnetization properties of the iron parts. The solutions showed good agreement with experimental data. Based on the equivalent magnetic circuit equation, the influence of design parameters on the force-to-armature displacement curves was mathematically derived and experimentally verified. In this way, dominant design parameters could be analytically determined.

• International Journal of Precision Engineering and Manufacturing
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• 제7권2호
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• pp.46-51
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• 2006

In this study, the electromagnetic characteristic of a flat-type two-dimensional proportional solenoid were analyzed by the magnetic reluctance method. The magnetic equivalent circuit equation for the solenoid was derived by modeling the reluctance of air gaps and magnetic structural components such as pole core, armature and yoke. It was solved iteratively because of the nonlinear magnetization properties of iron parts. The solutions showed good agreement with experimental data. Based on the magnetic equivalent circuit equation, the influence of design parameters on force-to-armature displacement curves was mathematically derived and experimentally verified. In this way, dominant design parameters could be analytically determined.

• Journal of Electrical Engineering and Technology
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• 제12권3호
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• pp.1219-1226
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• 2017

This paper presents the hybrid stepping machine for linear oscillating generators. The focus of the work is the suggestion of the improved model through the comparison of proposed models ; new flux concentrating PMs mover of the hybrid stepping generator is proposed based on the symmetrical and non-symmetrical stator cores of the surface mounted PMs mover, and non-slanted PMs and slanted PMs of the flux concentrating PMs mover. It is achieved using equivalent magnetic circuit considering leakage elements. Finally, this study suggests new hybrid stepping structure of linear oscillating generator.