• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2000.02a
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• pp.29-32
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• 2000

Superconducting transmission cable is one of interesting part in power application using high temperature super-conducting wire as transformance. One important parameter in HTS cable design is transport current distribution because it is related with current transmission capacity and loss. In this paper, we present the calculation theory of current distribution for multi-layer cable using the electric circuit model and in example, calculation results of current distribution and AC loss in each layer of 4-layer HTS transmission cable.

• JSTS:Journal of Semiconductor Technology and Science
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• v.10 no.1
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• pp.11-19
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• 2010

Register transfer level power macromodeling is well known as a promising technique for accurate and efficient power estimation. This paper proposes effective approaches based on the tablebased method for the RTL power macro-modeling. The new parameter SD, which characterizes the distribution of switching activities for each gate in the circuit, is one of the contributions. The new parameter SD has strong correlation with power consumption. We also propose an accurate table reference method considering the circuit characteristics. The table reference method is applicable for every table-based method and outputs more accurate power value. The experimental results show that the combination of the proposed methods reduces max error 30.36% in the best case, comparing conventional methods. The RMS error is also improved 1.70% in the best case.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.810-812
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• 2000

Superconducting transmission cable is one of interesting part in power application using high temperature superconducting wire as transformer. One important parameter in HTS cable design is transport current distribution because it is related with current transmission capacity and loss. In this paper, we calculate inductance and current distribution for 4-layer cable using the electric circuit model and compare calculation results of transport current losses by monoblock model and Norris equation

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1989.06a
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• pp.63-65
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• 1989

Piezoelectric BaTiO$_3$-polymer composite were investigated for dielectric and piezoelectric properties with the barium titanate active particle size. Under the condition of the same density and ceramic volume ratio of composite, the dielectric and piezoelectric constant of composite are increasing as the ceramic particle size in composite are increasing. The surface layer model was quoted to explain these phenomena in our system and experimentally confirmed. The connectivity parameter of modified cube model of composite was calculated from the dielectric constant variation as their particle size. The connectivity parameter X and Y were 77.8% and 98.9% respectively. It means that the barium titanate particle distribution in composite nearly approach to the parallel mode. It was experimentally confirmed that the surface layer has low dielectric and nonferroelectric properties. Dielectric constant and thickness of surface layer were calculated from the equivalent circuit of composite.

• Journal of Electrical Engineering and Technology
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• v.6 no.1
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• pp.1-7
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• 2011

This paper proposes an enhanced noise robust algorithm for fault location on double-circuit transmission line for the case of single line-to-ground (SLG) fault, which uses distributed parameter line model that also considers the mutual coupling effect. The proposed algorithm requires the voltages and currents from single-terminal data only and does not require adjacent circuit current data. The fault distance can be simply determined by solving a second-order polynomial equation, which is achieved directly through the analysis of the circuit. The algorithm, which employs the faulted phase network and zero-sequence network with source impedance involved, effectively eliminates the effect of load flow and fault resistance on the accuracy of fault location. The proposed algorithm is tested using MATLAB/Simulink under different fault locations and shows high accuracy. The uncertainty of source impedance and the measurement errors are also included in the simulation and shows that the algorithm has high robustness.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1151-1153
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• 2003

In this paper, switching surge voltage distribution in stator windings of induction motor driven by IGBT PWM inverter is studied. To analyze the irregular voltage of stator winding, equivalent circuit model of inverter-cable-motor was proposed and high frequency parameter is computed by using finite element method (FEM). Electromagnetic transient program (EMTP) analysis of the whole system for induction motor and PWM inverter is proposed. In order to experiment, an induction motor, 380 [V], 50 [HP], with taps from one phase and a switching surge generator was built to consider the voltage distribution.

• Proceedings of the KIPE Conference
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• 2002.11a
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• pp.17-20
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• 2002

In this paper voltage distribution in stator windings of induction motor driven by IGBT PWM inverter is studied. To analyze the irregular voltage of stator winding, equivalent circuit model of inverter-cable-motor was proposed and high frequency parameter is computed by using finite element method (FEM). Electro-magnetic transient program (EMTP) analysis of the whole system for induction motor and PWM inverter is proposed. Induction motor, 50[HP], and a switching surge generator was built to consider the voltage distribution. The results of EMTP analysis compared with experimental results.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.700_701
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• 2009

In comparison with conventional motors, Superconducting Homopolar Synchronous Motors (SHSMs) have advantages that it generates high magnetic field by superconducting winding. Therefore, superconducting coil used in SHSM can reduce the motor size and enhance the motor efficiency for high torque applications under the space constraints for propulsion system. During the design process of SHSM, it is required to evaluate the performance of initial design model, that is accurately analyzed using 3D magnetic field modeling large air-gap and flux distribution of axial direction is properly taken into account. In this paper, we analyze magnetic field of a homopolar motor with a 4-pole homopolar rotor and a stator of 3 phase windings. The field analysis is done using 3D finite element analysis which can reflect the end effect and overhang winding. And we extract mutual inductances between a rotor wind and the 3 stator windings. The extracted inductances are used for evaluation of overall motor performances that are calculated with generalized circuit theory of electrical machines.

• ETRI Journal
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• v.31 no.2
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• pp.225-227
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• 2009

A new planar metamaterial (MTM) with simultaneous negative values of permittivity (${\varepsilon}$) and permeability (${\mu}$) is proposed. Our MTM is composed of two identical copper patterns etched on both sides of dielectric laminate, which is very thin and easy to fabricate. Unlike conventional MTMs, the proposed structure shows a negative refractive index (NRI) behavior with respect to a normally incident wave. To explain the underlying principle of the NRI characteristics, an equivalent resonant circuit model based on surface current density distribution is investigated. An eigenmode analysis and a three-dimensional wave simulation for the stacked MTM prism are also performed to verify the existence of negative refraction. The experimental results from the transmission and reflection measurement ensure the validity of our design approach and show good agreement with the theoretically predicted effective medium parameters.

• Proceedings of the KIEE Conference
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• summer
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• pp.1046-1048
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• 2004

Inductance is an important parameter determining the characteristics of current waveform in electric motors. There are many kinds of inductances, however, self and mutual inductances are the major components. These inductances are changed under the variation of the magnetic circuit, current, frequency etc., even in the same winding distribution. Therefore this paper deals with the characteristics of inductance according to the shape of stator tooth. The analysis model is newly developed motor made of SMC(Soft Magnetic Composite) to reduce the core loss in high speed. the result of this paper gives the basic understandings of inductance to extend the applications of the motors.