• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.11
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• pp.440-444
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• 1985

Voltage equations of a synchronous machine are derived from the electromagnetic field theory in order to develop a new equivalent circuit model considering core loss. The result from the new equivalent circuit model is superior to that of the conventional one in the analysis of machine performance and characteristics on optimal efficiency control of a synchronous motor.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.2043-2045
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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.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.1
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• pp.109-112
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• 2013

It is well known that the maximum torque of a 3-phase induction motor does not vary as the resistance of rotor varies by proportional shifting. However, proportional shifting is derived using simplified equivalent circuit of induction motor. Therefore, there are some errors in the torque characteristics shown in the text book. This paper presents the torque characteristics using not simplified equivalent circuit but equivalent circuit. Errors produced by simplified equivalent circuit are presented.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.6
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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.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.983-984
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• 2011

An effective estimation method of equivalent circuit parameters of three-phase induction motor by using FEM is presented in this paper. Arbitrary three torque-speed points at asynchronous speed on the torque-speed curve are required by using time-stepping FEM, then the equivalent circuit parameters of IM can be calculated rapidly with presented method. After obtaining the equivalent circuit parameters, the general analysis method based on equivalent circuit can be used to get entire torque-speed curve very quickly. Although the purely numerical method such as FEM also can estimate torque-speed curve directly and accurately, however, usually this process is time consuming.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.60 no.4
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• pp.220-226
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• 2011

This paper proposes a straightforward method of analyzing the operation characteristics for the capacitor run single-phase induction motor from the traditional equivalent circuit based on the revolving field theory. The proposed method consists of five procedures as follows: mechanical loss segregation, iron loss segregation and calculation of the equivalent circuit parameters, recalculation of parameters of the main winding side, calculation of the auxiliary winding magnetizing reactance and effective turn ratio, and analyzing the operation characteristics for this motor. When the characteristics are analyzed, the segregated mechanical and iron losses are considered as a loss resistance across input terminals of the equivalent circuit for the analysis. The validity of the proposed method is verified from the comparison between the computed results and the experimental ones for the operation characteristics.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.27-30
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• 2007

This paper deals with an equivalent circuit model for RF passive components. Rational functions are obtained from the frequency responses of EM simulation by using Foster canonical partial fraction expressions. The Vector Fitting(VF) and the Adaptive Frequency Sampling(AFS) scheme are also implemented to obtain the rational functions. A passivity enforcement algorithm is applied to ensure the stability of the equivalent circuit model. In order to verify the schemes, S parameters of the equivalent circuit model is compared to those of EM simulation in case of the microstrip line structure with 3 slots in ground.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.890-895
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• 2002

The equivalent electroacoustic circuit approach has been conventionally used for estimating the absorption coefficient of a single layer perforated plate system. When the single layer system is extended to the multiple layer ones, however, it is found that an analogy error has been involved in the equivalent electroacoustic parallel circuit approach proposed by previous investigators. The analogy error is demonstrated by the corrected equivalent electroacoustic circuit approach in this study.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.8 no.1
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• pp.1-5
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• 2009

In this paper, we propose a method that applies Vector Fitting (VF) technique to the equivalent circuit model for RF passive components. These days wireless communication system is getting smaller and smaller. So EMI/EMC is an issue in RF. We can solve PI/SI (Power Integrity/Signal Integrity) that one of EMI/EMC problem apply IFFT for 3D EM simulation multiple with input signal. That is time consuming task. Therefore equivalent circuit model using RF passive component is important. VF schemes are implemented to obtain the rational functions. S parameters of the equivalent circuit model is compared to those of EM simulation in case of the microstrip line structure.

• 한국정보통신설비학회:학술대회논문집
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• 2004.08a
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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.