• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1664-1665
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• 2011

This paper presents a derivation of the capacitance of a shielded microstrip line using the Finite Element Method (FEM). The first approach adopts a 2-D version of Gauss's theorem and an approximation of integral to finite differencing. In this case, the choice of a contour and the size of a mesh affects the validity of the capacitance. Next, the method for deriving the capacitance by using of energy relation is shown. Finally, the simulation results are compared to those of the commercial tool (COMSOL) adopted FEM.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 A
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• pp.179-182
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• 2003

A simulation on bootstrapping circuit has been performed by modelling a coaxial cable as a transmission line. It is shown that the bootstrapping circuit could be unstable due to the transmission line effect though an ideal amplifier is used. While the conventional bootstrapping circuit does not cancel the input capacitance of the input buffer, a new bootstrapping circuit that cancels input capacitance of the input buffer has been proposed. The proposed bootstrapping circuit consists of the input buffer of which gam is larger than 1 and a feedback resistor to control the loop gain. The proposed bootstrapping circuit has higher input impedance than that of the conventional circuit.

• 대한전자공학회논문지SD
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• 제41권11호
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• pp.53-59
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• 2004

본 논문은 3차원 연결선 모형을 이용하여 효율적으로 회로 연결선에 기생하는 커패시턴스 성분을 추출하는 방법을 제안한다. 제안한 방법은 경험식에 의한 방법 중 2차원 연결선 모형의 커패시턴스를 추출하는 알고리즘을 이용하여 수행시간을 개선하였고, 정확도의 오차를 줄이기 위하여 3차원 커패시턴스 추출에서 이용되는 모형화 방법을 적용하였다. 이 방법은 FastCap을 이용하여 실험한 결과와 비교하면 1.8%의 오차 범위에서 952배의 시간 이득을 얻을 수 있다. 제안한 방법은 VLSI 시스템의 칩 내 외부 연결선의 전기적 변수 추출에 효과적으로 이용될 수 있을 것이다.

• International Journal of Air-Conditioning and Refrigeration
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• 제6권
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• pp.1-13
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• 1998

The basic heat transfer process that occurs in a building can best be illustrated by an electrical circuit network. Present paper reports the dynamic simulation of annual energy consumption in an office building by the thermal resistance capacitance network method. Unsteady thermal behaviors and annual energy consumption in an office building were examined in detail by solving the simultaneous circuit equations of thermal network. The results are used to evaluate the accuracy of the modified BIN method for the energy consumption analysis of a large building. Present thermal resistance-capacitance method predicts annual energy consumption of an office building with the same accuracy as that of response factor method. However, the modified BIN method gives 15% lower annual heating load and 25% lower cooling load than those from the present method. Equipment annual energy consumptions for fan, boiler and chiller in the HVAC system are also calculated for various control systems as CAV, VAV, FCU+VAV and FCU+CAV. FCU+CAV system appears to consume minimum annual energy among them.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2010-2012
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• 2005

Activated carbon was activated with chemical treatment to attain high surface area with porous structure. We have been considered activated carbon is the ideal material for high voltage electric double layer capacitor due to their high specific surface area, good conductivity and chemical stability. In this study we found that increase in electrochemical capacitance due to activated carbon. Also chemically activated carbon and water treatment have resulted larger capacitance and also exhibits better electrochemical behavior, and is about 15% more than in untreated state. The structural change in activated carbon through chemical treatment activation was investigated by using SEM and XRD. In this study, the dependence of the activation behavior with KOH in the micro structure of host materials will be discussed. Furthermore, the relation to the electric double layer capacitance, especially the specific capacitance per unit area, is also discussed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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• pp.97-99
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• 1998

This paper presents a numerical study of the behavior of the transformer winding, when stressed by the standard impulse voltage. The mathematical model of the transformer takes several points into the account. Capacitance of not adjacent winding as well as adjacent winding, eddy current loss caused by self and mutual inductance given as the functions of frequency. Not like the previous approach where calculation of capacitance is performed, in average sense. In this paper, capacitance of both adjacent and not adjacent winding is calculated using the numerical approach(B.E.M.), so they can get the more accurate value of capacitance. Because of frequency dependency of inductance, numerical-laplace-transform technique is required. Finally, to validate this approach, a simple test winding is simulated.

• 전기학회논문지
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• 제57권6호
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• pp.1012-1016
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• 2008

[ $TiO_2-V_2O_5$ ] sol was fabricated using sol-gel method and $TiO_2-V_2O_5$ thin films were fabricated using dip-coating method. $V_2O_5$ sol was added 0.01mole, 0.03mole, 0.05mole into $TiO_2$ sol. As a results of crystalline properties, $V_2O_5$ peaks were not found in spite of $V_2O_5$ additive. Thickness of thin films increased $0.1{\sim}0.25{\mu}m$ every a dipping. Capacitance of thin films increased with increasing heat treatment temperature and it increased largest at $700^{\circ}C$. Capacitance of thin films decreased with increasing $V_2O_5$ additive and it increased largest at 0.01mole. Because adsorption time and desorption time of thin films was about 2 minutes 40 seconds and about 3 minutes 40 seconds respectively, adsorption time was faster about 1 minutes than desorption time.

• Journal of Power Electronics
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• 제12권1호
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• pp.40-48
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• 2012

This paper proposes the State-of-charge (SOC) estimator of a LiPB Battery using the Extended Kalman Filter (EKF). EKF can work properly only with an accurate model. Therefore, the high accuracy electrical battery model for EKF state is discussed in this paper, which is focused on high-capacity LiPB batteries. The battery model is extracted from a single cell of LiPB 40Ah, 3.7V. The dynamic behavior of single cell battery is modeled using a bulk capacitance, two series RC networks, and a series resistance. The bulk capacitance voltage represents the Open Circuit Voltage (OCV) of battery and other components represent the transient response of battery voltage. The experimental results show the strong relationship between OCV and SOC without any dependency on the current rates. Therefore, EKF is proposed to work by estimating OCV, and then is converted it to SOC. EKF is tested with the experimental data. To increase the estimation accuracy, EKF is improved with a single dominant varying parameter of bulk capacitance which follows the SOC value. Full region of SOC test is done to verify the effectiveness of EKF algorithm. The test results show the error of estimation can be reduced up to max 5%SOC.

• 전기전자학회논문지
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• 제22권1호
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• pp.209-212
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• 2018

본 논문에서는 P(VDF-TrFE)유기물 강유전체 기반 metal-ferroelectric-metal (MFM) capacitor 와 차세대 반도체 물질인 질화갈륨 반도체를 활용한 네거티브 커패시턴스 전계효과 트랜지스터를 제작 및 분석 하였다. 27 nm의 두께의 P(VDF-TrFE) MFM 커패시터의 분극지수는 4 MV/cm에서 $6{\mu}C/cm^2$ 값을 나타내었으며 약 65 ~ 95 pF의 커패시턴스 값을 나타내었다. 강유전체의 커패시턴스와 전계효과 트랜지스터의 커패시턴스 매칭을 분석하기 위해 제작된 P(VDF-TrFE) MFM 커패시터는 GaN 전계효과 트랜지스터의 게이트 전극에 집적화 되었으며 집적화되기 전 104 mV/dec 의 문턱전압 이하 기울기에서 82 mV/dec 값으로 개선된 효과를 보였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.179-179
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• 2009

This is for the electrical characterization by IDC pattern using BST$(Ba_{0.5}Sr_{0.5}TiO_3)$ thin film. BST materials had been chosen for high frequency applications due to it's high permitivity and tunability. The BST thin films have been deposited on $Al_2O_3$ Substrates by Nd-YAG pulsed laser deposition with a 355nm wavelength at $700\;^{\circ}C$. The post deposition annealing at $750^{\circ}C$ in flowing $O_2$ atmosphere for 1 hours. The capacitance of IDC patterns have been measured from 1 to 10 GHz as a function of electric field ($\pm40$ KV/cm) at room temperature using inter-digital Au electrodes deposited on top of BST. The IDC patterns have three type of fingers number. For the 10 pairs finger was the best capacitance onto $Al_2O_3$ substrate. The capacitance was 0.9pF. Also Dielectric constant was been 351 at 100 mTorr and annealing temperature $750^{\circ}C$ for 1 hour. The loss tangent was been 0.00531.