• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.525-528
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• 2000

This paper presents a circuit analysis and cotnrol example of favored configuration 6/4 SRM. SRM modeling and analysis are necessary for experiment. Thus this paper proposes a SRM modeling with PI controller (of driving converter) input voltage chopping and inductance profile when rotor position transformed. Through this simulation the designer can predict operating states of systems over a broad range of operating conditions.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2019년도 전력전자학술대회
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• pp.483-484
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• 2019

This paper proposes a harmonic state space (HSS) modeling of DC microgrid. In the HSS model, nonlinear equations for the switched circuit model are transformed into multiple linear equations. The simulation results have shown the HSS modeling is comparable with PSIM simulation.

• Journal of electromagnetic engineering and science
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• 제12권4호
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• pp.240-246
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• 2012

This paper presents a novel modeling technique for traces that cross a defected ground structure. A simple and accurate equivalent circuit model provides clear insight into the coupling mechanism between a microstrip line and a slot or split. The circuit models consist of a transformer as the coupling mechanism and LC resonators as the ground with a slot or split structure. Resistors, capacitors, and inductors are added to the model to increase accuracy and equivalence at high frequency. Simulated and measured S-parameters are presented for defected ground structures. The accuracy and validity of the proposed equivalent circuit model is verified by evaluation of the S-parameter characteristics of the defected ground structures and comparison with measured results.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권12호
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• pp.589-595
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• 2004

The ESD protection characteristic of chip varistors on a circuit board can not be analyzed by using a conventional circuit simulator due to its microwave characteristic. Thus, by employing Agilent's microwave circuit simulator ADS, we showed that the ESD Protection characteristic or chip varistors can be investigated. order to got more precise simulation results, a chip varistor model was extracted from the electrical characteristic of a TDK's chip varistor and the distributed circuit based pattern was designed as the ESD propagation path. The simulation results showed that the ESD protection characteristic of a chip varistors can be improved drastically by reducing the ESD propagation path.

• 전기학회논문지
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• 제56권6호
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• pp.1105-1110
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• 2007

This paper describes an equivalent circuit modeling of 4-port connector system. A coupled transmission line was designed and fabricated, mimicking a 4-port connector system, and then S-parameters were measured using 4 port VNA (Vector Network Analyzer). The S-parameters from measurement and from Full-wave simulator coincided quite nice. By using these S parameters, an equivalent circuit parameters for a 4-port system was obtained. The time domain response from the equivalent circuit model matched to the signals, which was measured using TDR(Time Domain Reflectometry) meter. We were also convinced that there should be enough bandwidth to get a meaningful time domain result from Fourier inverse transformation of the S parameters. In addition, we applied the conversion algorithm to the 4-port connector system, which calculates the S-parameters of a 4 port system using the data from a 2-port VNA with the other ports open. Comparison of the two data, one from measurement and the other one from the conversion algorithm, was made in this manuscript.

• 전기학회논문지
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• 제56권6호
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• pp.1087-1091
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• 2007

Exact impedance modeling of the electrode/electrolyte interface is important in bio-signal sensing electrode development. Therefore, the investigation of the equivalent circuit models for the interface has been pursued for a long time by several researchers. Previous circuit models fit the experimental results in limited conditions such as frequency range, type of electrode, or electrolyte. This paper describes a new electrical circuit model and its capability of fitting the experimental results. The proposed model consists of three resistors and two constant phase elements. Electrochemical impedance spectroscopy was used to characterize the interface for Au, Pt, and stainless steel electrode in 0.9% NaCl solution. Both the proposed model and the previous model were applied to fit the measured impedance results for comparison. The proposed model fits the experimental data more accurately than other models especially at the low frequency range, and it enables us to predict the impedance at very low frequency range, including DC, using the proposed model.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.11-16
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• 2001

Recent publications showed that a pair of neighboring printed circuit board (PCB) windings can be used as a contactless energy transfer device. As a continued study on this area, the current paper presents the modeling, analysis, and application of the neighboring PCB windings with an emphasis on their circuit properties and device characteristics as a contactless energy transfer device. Theoretical results of the paper are confirmed with experiments on a prototype contactless energy transfer circuit that delivers 24W output power at $68\%$ efficiency through two 35mm-diameter PCB windings separated each other by 2.4mm.

• 한국정보통신학회논문지
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• 제6권3호
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• pp.421-426
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• 2002

Hybrid cascade multilevel PWM inverter has advantages of hybrid structure which enhances the better utilization of power semiconductor switches, that is, both hi호 power-low frequency switch, GTO and low power-high frequency switch, IGBT can be used in the same circuit. In this paper, a static var compensator using hybrid cascade 5-level PWM inverter is presented for high voltage/high power applications. The proposed system is modelled by circuit DQ transformation, and thus an equivalent circuit is obtained which reveals the important characteristics of the system and lead to the related equations. Finally, circuit structure and characteristics is presented and the validity of the characteristics analysis is shown through PSIM simulation.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2004년도 하계학술대회
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• pp.386-389
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• 2004

This thesis complemented the weak points that the existing theses did not represented a phase characteristic as the equivalent circuit by applying 4-port simulation to DGS (Defected Ground Structure) characteristic and an equivalent circuit, which are the transmission line structure that has the defect made in the ground surface. We used a distribute device and a lumped device, obtained the equivalent circuit by applying the structure of balun to a discontinuous part. An indicated DGS (Defected Ground structure) is a dumbbells-shaped single defect, we indicated satisfying a magnitude and phase characteristics by applying this equivalent circuit.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.688-692
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• 2000

This study proposed design parameters of opening spring of circuit breaker that cut off the over-current in order to protect the electric device about opening speed using the energy method. We simulated the opening kinetic energy, the potential energy of opening spring and the design parameters of opening spring with respect to opening speed of VCB (Vacuum Circuit Breaker)'s moving contactor which has 24kV 25kA break capacity. From the result of simulation the initial tensional force and the final tensional force of the opening spring chose 107kgf and 282kgf respectively. Through the dynamic analysis using ADAMS, We verified that the opening speed of moving contactor satisfied break capacity of VCB and analyzed opening dynamic characteristics of VCB such as the opening displacement, the opening velocity and the opening acceleration of moving contactor in time domain.