• Journal of Advanced Navigation Technology
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• v.21 no.4
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• pp.371-376
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• 2017

In this paper, we propose a magnetic resonant WPT(wireless power transfer) scenario using a large coil resonating at 6.78 MHz, and compare the characteristics through a three-dimensional electromagnetic field simulation and a magnetic resonant WPT equivalent circuit. The magnetic resonant WPT equivalent circuit proposed in this paper considers the parasitic capacitance generated between the coils in addition to the conventional equivalent circuit. Based on this analysis, we fabricated the magnetic resonant WPT coil and compared it with simulation prediction. As a result of comparison, the transfer characteristics and the resonance frequency shift can be predicted. Error proposed characteristics of equivalent circuit for the magnetic resonant WPT and the measured values are estimated to be ${\Delta}{\mid}S11{\mid}=1.31dB$ and ${\Delta}{\mid}S21{\mid}=1.21dB$, respectively.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.932-939
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• 2012

This paper presents an equivalent circuit model of a LIPB (Li-Ion Polymer battery) for Hybrid Electric Vehicles (HEVs). The proposed equivalent circuit can be used to predict the charging/discharging characteristics in time domain as well as the impedance characteristic analysis in frequency domain. Based on these features, a one-cell model is established as a function of Depth of Discharge (DoD), and a 48-cell model for a battery pack was also established. It was confirmed by experiment that the proposed model predict the discharging and impedance (AC) characteristics quite accurately at different constant current levels. To check the usefulness of the proposed circuit, the model was used to simulate a motor driving circuit with an Insulated Gate Bipolar Transistor (IGBT) inverter and Brushless DC (BLDC) motor, and it is confirmed that the model can calculate the battery voltage fluctuation in time domain at different DoDs.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.55-57
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• 2005

This paper deals with the analysis of bearing current in H-bridge seven level multilevel inverter fed induction motor. In the previous researches utilized electromagnetic equations to derive the parasitic capacitance or measured capacitance parameters, but we used FEM to derive parasitic capacitances and defined the equivalent circuit parameters in our strategy. Then we compared suggested method with conventional method in 60 [Hz] no load condition.

• Geophysics and Geophysical Exploration
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• v.17 no.4
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• pp.242-246
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• 2014

Spectral induced polarization (SIP) is a useful technique, which uses electrochemical properties, for exploration of metallic sulfide minerals. Equivalent circuit analysis is commonly conducted to calculate IP parameters from SIP data. An equivalent circuit model, which indicates the SIP response of rock, has a non-uniqueness problem. For this reason, it is very important to select the proper model for accurate analysis. Thus, this study focused on suggesting a new model, which suitable for the analysis of an anomalous SIP response, such as ore. A suitability of the new model was verified by comparing it with the existing Dias model and Cole-Cole models. Analysis errors were represented as a normalized root mean square error (NRMSE). The analysis result using the Dias model was the NRMSE of 10.50% and was the NRMSE using the Cole-Cole model of 17.03%. Howerver, because the NRMSE of the new model is 0.87%, it is considered that the new model is more useful for analyzing the anomalous SIP data than other models.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.1960-1966
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• 2014

The rotor overhang is used to enhance the air-gap flux and improve the power density. Due to the asymmetry in the axial direction caused by the overhang, a time consuming 3D analysis is necessary when designing a motor with overhang. To solve this problem, this paper proposes an equivalent magnetic circuit model (EMCM) which takes account overhang effects without a 3D analysis by using effective air-gap length. The analysis time can be reduced significantly via the proposed EMCM. A reduction in the analysis time is essential for a preliminary design of a motor. In order to verify the proposed model, a 3-D finite-element method (FEM) analysis is adopted. 3-D FEM results confirm the validity of the proposed EMCM.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.155-158
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• 1997

In design of current transformer, equivalent circuit parameters is obtained by electromagnetic analysis and used circuit simulation. Precise core secton area and turns of coil can be determined by circuit analysis. Therefore exact design of current transformer is possible by field and circuit analysis.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.7
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• pp.11-19
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• 1998

A signal line potential variation due to the delta-I noise was physically investigated in CMOS integrated circuits. An equivalent circuit for the noise analysis was presented. The signal line was modeled as segmented RC-lumped circuits with the ground noise. Then the equivalent circuit was mathematically analyzed. Therebvy a new signal line potential variation model due to the switching mosie was developed. Th emodel was verified with 0.35.mu.m CMOS deivce model parameters. The model has an excellent agreement with HSPICE simulation. Thus the proposed model can be dirctly employed in the industry to design the high-performance integrted circuit design as well as integrated circuit package design.

• 전기의세계
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• v.24 no.1
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• pp.29-42
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• 1975

In this paper, the electrical angle between two winding axes in the stator of the capacitor motor is put optional angle, deviding the space harmonics in its magnetic field of two windings and the leakage flux into the forward revolving field and the backward one by the revolving-field theory, its equivalent circuit which consider mutual induction between two windings is depicted. In the depicted equivalent circuit, the rotor resistance for the fundamental flux is devided into the resistance for the rotor bar and endring, and the rotor leakage reactance for the fundamental is devided into the skew leadage reactance and the other, and each circuit constants for each harmonics is expressed in terms of the circuit constants for the fundamental, so it mades easy to determine the characteristics for the capacitor motor. As the circuit constant ratios to the magnetizing reactance of the fundamental are used, motors which have same circuit constant ratios should be resembled in their characteristics.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.3
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• pp.45-54
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• 2004

Microwave characteristics of ridge type CPW traveling-wave(TW) electroabsorption modulator and photodetector are affected by the thickness of intrinsic layer, width of guiding layer, and the separation of signal and ground electrodes. These factors are determined effective index of microwave and characteristic impedance due to changing of capacitance(C) and inductance(L) of device. However, conventional equivalent circuit of TW-structure is approximated to microstrip and CPW transmission line by distribution of electric and magnetic fields, respectively. In this paper, we analyzed microwave characteristics of TW-structure and found more accurate value of C and L by using finite difference time domain (FDTD) method. These values are adopted circuit element of equivalent circuit. Microwave characteristics obtained by the FDTD and equivalent circuit model show good agreement.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.1
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• pp.82-89
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• 2001

This paper proposes several methods to analyze dynamic and static characteristics of HVDC inverter system. The characteristic analysis is essential of the controller and filter design of the HVDC inverter system. Dynamic characteristic can be analyzed with EMTP simulation and static characteristic can be obtained by solving newly proposed load flow equation which includes the filter and load characteristic. New simple per-phase-equivalent circuit is also proposed. In this circuit, HVDC inverter is considered as a current source depending on the on-off status of switch. Dynamic and static characteristic can be analyzed by the proposed per-phase-equivalent circuit. For the optimal filter design, various performance criteria are proposed. The performance index, based on the per-phase-equivalent circuit, is calculated. Voltage harmonics and filter power loss are selected as criteria. Optimization procedure is explained to find optimal passive filter parameters.