• Transactions on Electrical and Electronic Materials
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• v.14 no.2
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• pp.105-109
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• 2013

In order to develop high voltage (HV) insulation materials, epoxy/spherical alumina composites with two different particle sizes (in ${\mu}m$) were prepared and a dynamic mechanical analysis (DMA) and electrical insulation breakdown strength test were carried out in sphere-sphere electrodes and the data were estimated using Weibull statistical analysis. Alumina content varied from 50 to 70 wt%. The electrical insulation breakdown strength for epoxy/alumina (50 wt%) was 44.0 kV/1 mm and this value decreased with increasing alumina content. The effects of insulation thickness and alumina particle size on the insulation breakdown strength were also studied. The insulation thickness varied from 1 mm to 3 mm, and the particle sizes were 7.3 or $40.3{\mu}m$.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.5
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• pp.675-683
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• 2018

In this paper, we have proposed a design and verification methods of electrical system and power loads for unmaned aeriel vehicles(UAVs) through electrical load analysis. In order to meet a UAV system requirement and electrical system specifications, we have designed an electrical power system for efficient power supply and distribution and have theoretically analyzed the power loads according to the power consumption and power bus design of UAV. Using electrical system rig, the designed electrical power system has been experimentally verified. Also, we have performed several flight tests to verify the UAV electrical system and power loads. It is concluded that the proposed design and verification method of electrical system for UAV system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.223-224
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• 2005

In this paper, multiple regression analysis of the electrical characteristics for $HfO_2$ thin films grown by metal organic molecular beam epitaxy (MOMBE) was investigated. The electrical properties, such as, the accumulation capacitance and the hysteresis index, are the main factors to determine the characteristics of $HfO_2$ thin films. The input factors on the process are the substrate temperature, Ar gas flow, and $O_2$ gas flow. For statistical analysis, the design of experiments was carried out and the effect plots were used to analyze the manufacturing process. This methodology can predict the electrical characteristics of the thin film growth mechanism related to the process conditions.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.926-931
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• 2014

This paper presents the torque calculation and parametric analysis of synchronous permanent magnet couplings (SPMCs). Based on a magnetic vector potential, we obtained the analytical magnetic field solutions produced by permanent magnets (PMs). Then, the analytical solutions for a magnetic torque were obtained. All analytical results were extensively validated with the non-linear a two-dimensional (2D) finite element analysis (FEA). In particular, test results such as torque measurements are presented that confirm the analysis. Finally, using the derived analytical magnetic torque solutions, we carried out a parametric analysis to determine the influence of the design parameters on the SPMC's behavior.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.987-989
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• 2005

Axi-periodic analysis using magnetic vector potential is formulated in time harmonic field and applied to the field analysis for the end region of large turbo generator in this paper. By using axi-periodic analysis, the effect of flux shield, one of the structure placed in the end region of large turbo generator to prevent stator end from thermal damage, is studied, and eddy current loss in the flux shield is estimated for operation conditions. 3D FEA is used for the verification of presented analysis method. Because 3D flux distribution can be calculated with 2D modeling, magnetic field showing 3D distribution can be effectively calculated by axi-periodic analysis comparing with 3D FEA.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.4
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• pp.163-168
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• 2017

This paper presented an evaluation method for the efficiency uncertainty of a three-phase induction motor using finite element analysis. The motor efficiency in the finite element analysis is calculated by the loss separation method as in the actual test. In the process of evaluating the efficiency uncertainty, the difference between the finite element analysis and the actual test is the method of calculating the type-A / B standard uncertainty of the input quantity to estimate the efficiency and each losses. For the input quantities which can confirm the instantaneous values with respect to time, the type-A standard uncertainty in the finite element analysis is calculated from the RMS values or average values having separate periods in the steady state. And, the type-B standard uncertainty in the finite element analysis is assumed to be zero. Also, this paper compared and analyzed the efficiency uncertainty evaluated by the proposed method and the efficiency uncertainty through the actual test.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.288-294
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• 2015

Recently, the module-integrated converter has shown an interest in the photovoltaic generation system. In this system, the high frequency transformer should be compact and efficient. The proposed method is based on the correlation characteristic between the copper and core loss to minimize the loss of transformer. By sizing an effective cross-sectional area and window area of core, the amount of loss is minimized. This paper presents the design and analysis of high frequency transformer by using the 3D finite element model coupled with DC-DC converter circuit for more accurate analysis by considering the nonlinear voltage and current waveforms in converter circuit. The current waveform in each winding is realized by using the ideal DC voltage source and switching component. And, the thermal analysis is performed to satisfy the electrical and thermal design criteria.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.3
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• pp.362-368
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• 2009

Electrical fires have been occurred continuously in spite of installing ELB. Therefore the concern with the electrical arc-fault that cause the fire has growing. This paper measured series arc fault currents by the method of arc generator test in UL standard 1699. The used analysis methods in this paper are three different ways using DWT(discrete wavelet transform) those are frequently used for the arc fault current signal analysis. The arc fault detection probability is 100 % by method using noise-energy/shoulder-duration ratio of approximation coefficient. As these results, the variation of noise-energy and shoulder-duration ratio of approximation coefficient are founded important factors for the analysis of arc fault.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.322-324
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• 2000

This paper introduces the concepts of UML(Unified Modeling Language) and the applying this technique for implementing voltage stability analysis program. Conventional function-oriented software development methodologies are inadequate to support further maintenance and enhancement. To overcome drawbacks of these methodologies, this paper proposes applying object-oriented technology for voltage stability evaluation software development. In this paper, a modal analysis approach, a steady-state voltage stability evaluation method, is used and UML is applied to the analysis and design for software development.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.4B no.1
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• pp.1-5
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• 2004

This paper deals with the design and analysis of a 2-phase Switched Reluctance Motor (SRM) used for the cooling fan motor of a refrigerator. To reduce the dead zone and improve the efficiency, the snail-earn type rotor pole and the asymmetric stator pole are investigated. For the optimal shape design, the performances of each model are obtained from numerical calculation results by 2D time-stepping finite element method (FEM) coupled with circuit equations. The accuracy of analysis is verified by comparing the analysis results with experimental data. According to the investigation results, improved shapes of stator and rotor poles are proposed.