• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.1053-1056
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• 1998

Package strutures for RF circuit design are characterized and their equivalent circuitsare developed. The circuit parameters are extracted by using the commercial 3-dimensional field solver. The circuit models are verified by using the full-wave analysis in the RF region. It is demonstarted with the developed circuit models that the packages have substantial effects on the RF circuit performances.

• Journal of Electrical Engineering and Technology
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• 제13권4호
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• pp.1759-1768
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• 2018

The energy density, power density and ohm resistance of battery change significantly as results of battery aging, which lead to decrease in the accuracy of the equivalent model. A parameter identification method of the equivale6nt circuit model with 3 R-C branches based on the test database of battery life cycle is proposed in this paper. This database is built on the basis of experiments such as updating of available capacity, charging and discharging tests at different rates and relaxation characteristics tests. It can realize regular update and calibration of key parameters like SOH, so as to ensure the reliability of parameters identified. Taking SOH, SOC and T as independent variables, lookup table method is adopted to set initial value for the parameter matrix. Meanwhile, in order to ensure the validity of the model, the least square method based on variable forgetting factor is adopted for optimizing to complete the identification of equivalent model parameters. By comparing the simulation data with measured data for charging and discharging experiments of Li-ion battery, the effectiveness of the full life cycle database and the model are verified.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.613-619
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• 2000

This paper presents a mettled to reduce the number of conductors of catenary system for estimating line constants. Conductors of a catenary system are grouped and reduced. For example, the model representing the contact and the messenger conductors with a single equivalent conductor is. probably more realistic than assuming the two conductors completely separated, since they are generally connected by droppers every few meters. Therefore, this paper shows the method to reduce the number of conductors using electric circuit theory. To verify the results, we compared the equivalent line constants obtained by proposed method with those obtained by measurement.

• 지구물리와물리탐사
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• 제17권4호
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• pp.242-246
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• 2014

지층의 전기화학적인 물성을 이용한 광대역유도분극(SIP) 탐사는 황화광물을 포함한 금속광물탐사에 유용한 기술이다. 탐사자료로부터 IP 물성을 계산하기 위해서는 등가회로 분석을 수행한다. 분석에 사용되는 암석의 SIP 반응을 고려한 등가회로 모델은 해의 비유일성이라는 문제를 가지기 때문에 정확한 분석을 위해 적절한 모델을 설정하는 것이 매우 중요하다. 따라서 이 연구는 SIP 이상반응을 나타내는 광석의 분석에 적합한 새로운 모델을 제안하고자 하였다. 이 모델은 기존의 Dias model과 Cole-Cole model의 비교를 통하여 적합성을 검증하였다. 그 결과, Dias model과 Cole-Cole model을 이용한 분석 결과의 NRMSE 오차는 각각 10.05%와 17.03%를 보였다. 하지만 제안한 새로운 모델의 NRMSE 오차는 0.87%로 상당히 낮았기 때문에 다른 모델보다 SIP 이상 자료의 등가회로 분석에 유용하고 판단하였다.

• 전기학회논문지
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• 제66권4호
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• pp.629-635
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• 2017

Free-Flooded Ring (FFR) transducer array for use in Sonar system can be driven with large amplitude in a wide frequency band due to its structural characteristics, in which two resonances of a ring mode (1st radial mode) and an inner cavity vibration mode occur in a low frequency band. Since its sound wave generation characteristics are not influenced by the water pressure, the FFR transducer array is widely used in the deep sea. So FFR has been recognized as a low-frequency active sound source and has received much attention ever since. In order to utilize the FFR transducer array for SONAR systems in military and industrial applications, its equivalent electric circuit model is necessary especially to design the matching circuit between the driving power amplifier and the FFR transducer array. Thus this paper proposes the equivalent electric circuit model of FFR transducer array by using measured values of parameter, and suggest the improved method of parameter identification. Finally it verifies the effectiveness of the proposed circuit model of FFR transducer array by experimental measurements.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권8호
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• pp.449-456
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• 2002

3D Equivalent magnetic Circuit Network Method (EMCNM) is comparatively the easy way that analyzes 3D models of Electric Machine by using permeance as a distributive magnetic circuit parameter under the existing magnetic equivalent circuit method and Numerical Method. The existing 3D EMCNM could not correctly describe the shape of an analysis target when using rectangular shape element or fan shape element, so it made errors when calculating permeance. Therefore, this paper proposes the trapezoidal element contained rectangular element, fan-shape element, and quadrilateral element to express a shape. The proposed method in this research was confirmed as a useful and an accurate method through comparing with the analysis result of SRM model that is sufficiently guaranteed by 2D-Analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.96-98
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• 2001

In this paper, the equivalent magnetic circuit and FEM are used to calculate force density of linear BLDC motor. The equivalent magnetic circuit is hard to exact compose for analysis model and it is just applied to linear system. To flexible design and reducing the calculated and analyzed time, magnetic circuit has to be used for designing the linear BLDC motor and deducing equation of force density. Force density as parameter of permanent magnet and coil-side width that are important to determined force density can be estimated using equation of force density. FEM is used to prove reliability of equation of force density and to consider the nonlinear system. Equivalent magnetic circuit and result of FEM are similar, but it is little different by friction loss at the experiment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.22-24
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• 1997

The 4-pole LHSM was composed of the figure-of-eight shaped 3-phase armature windings. DC field windings, and the segmented secondary with the transverse bar track. The motor was designed on the base of the performance characteristic equations and the equivalent circuit model, with the coefficients of the magnetic shape. These coefficients were computed from the analytical expressions and examined from FEM analysis. The magnetic equivalent circuit of 3-D model of LHSM was obtained. and this concept provided the equivalent models for 2-D FEM analysis. Therefore, the airgap field, the lift and thrust force were calculated and compared with the results of magnetic equivalent circuit method.

• Journal of Advanced Marine Engineering and Technology
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• 제30권8호
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• pp.907-918
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• 2006

In this study capacitance and dielectric loss factor were measured with low-voltage signal and the simulation of equivalent circuits for the data was conducted. As the result it was shown that the equivalent circuit model considered the grain-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 characteristics of varistor. It also seems that the proposed equivalent circuit model will be adopted for other BL type varistors.

• 한국음향학회지
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• 제15권4호
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• pp.77-82
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• 1996

본 연구에서는 샌드위치형 압전 트랜스듀서의 등가 회로 모델을 규명하는 방법을 제시하였다. 공기중에서 실험적으로 측정한 트랜스듀서의 전기적 어드미턴스와 이론적으로 계산된 어드미턴스의 오차가 최소가 되도록 하는 비선형 최적화 문제를 풀어 등가 회로에 관련된 미지 상수를 규명하였다. 예제 트랜스듀서에 대해 제안된 방법을 적용하여 등가회로를 모델링하고, 수중에서의 송신 음압 감도(TVR) 및 수신 읍압 감도(RVS)을 예측하고 실험치와 비교하여 규명된 등가 회로 모델의 타당성을 검증하였다.