• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.50 no.3
• /
• pp.146-152
• /
• 2001

This paper describes an accurate fault location algorithm based on sequence current distribution factors for a double-circuit transmission system. The proposed method uses the voltage and current collected at only the local end of a single-circuit. This method is virtually independent of the fault resistance and the mutual coupling effect caused by the zero-sequence current of the adjacent parallel circuit and insensitive to the variation of source impedance. The fault distance is determined by solving the forth-order KVL(Kirchhoff's Voltage Law) based distance equation. The zero-sequence current of adjacent circuit is estimated by using a zero-sequence current distribution factor and the zero-sequence current of the self-circuit. Thousands of fault simulation by EMTP have proved the accuracy and effectiveness of the proposed algorithm.

• ETRI Journal
• /
• v.20 no.1
• /
• pp.37-45
• /
• 1998

Reduced surface field lateral double-diffused MOS transistor for the driving circuits of plasma display panel and field emission display in the 120V region have been integrated for the first time into a low-voltage $1.2{\mu}m$ analog CMOS process using p-type bulk silicon. This method of integration provides an excellent way of achieving both high power and low voltage functions on the same chip; it reduces the number of mask layers double-diffused MOS transistor with a drift length of $6.0{\mu}m$ and a breakdown voltage greater than 150V was self-isolated to the low voltage CMOS ICs. The measured specific on-resistance of the lateral double-diffused MOS in $4.8m{\Omega}{\cdot}cm^2$ at a gate voltage of 5V.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.23 no.6
• /
• pp.773-779
• /
• 1986

In this paper, we discuss fabrication and characteristics of the Vertical Double diffused MOS(VDMOS) transistor. The epi layers of starting wafers are 18~22\ulcorner in thickness and 8~12\ulcornercm in resistivity. The channel regions are defined through the self-aligned double diffusion process. The characteristics of the fabricated VDMOS are breakdown voltage of 240V, threshold voltage of 2V, on-resistance of 226\ulcornerand transconductance of 3x10**-3 mho.

• Proceedings of the KIEE Conference
• /
• 2005.07b
• /
• pp.1002-1004
• /
• 2005

This paper describes the performance analysis and design of single-phase self-excited induction generators. In this study, it is proposed to design the proper capacitance for self-excitation and voltage regulation, also. This methods are based on the induced MMF equations between main and the auxiliary winding. For the least influence between the two capacitors, the self-excited capacitor is selected under no load condition, while the series capacitor is designed under loaded condition. For the steady state analysis, the equivalent circuit of single-phase induction generators is used as circuit modeling using the double-revolving field theory. The validity of proposal methods and designed generator system will be confirmed by experimental and computed results.

• International Journal of Advanced Culture Technology
• /
• v.10 no.4
• /
• pp.245-254
• /
• 2022

This study is a study to empirically verify the mediating effect on college life adaptation and career preparation behavior of college students. The purpose of this study is to empirically analyze the multi-mediated effects of major satisfaction, job stress, and self-directed learning. For this study, 216 university students were enrolled. For the collected data, SPSS Process macro was used. The result is as follows. First, there were multiple parallel mediating effects and multiple serial mediating effects on major satisfaction, job stress, and self-directed learning between college life adaptability and career preparation behavior. Second, the path of simple mediation and double mediation effect was found between college life adaptation and career preparation behavior. Based on the research, the necessity of revitalizing the program for revitalization of teaching activities and industry-academic cooperation activities in the major field and improvement of career preparation behavior and university life adaptation ability and follow-up research were suggested.

• Journal of Power Electronics
• /
• v.15 no.5
• /
• pp.1409-1420
• /
• 2015

In this paper, an algorithm using two bi-quad filters to suppress the wide-band resonance for PMSM servo systems is proposed. This algorithm is based on the double bi-quad filters structure, so it is named, "double bi-quad filter." The conventional single bi-quad filter method cannot suppress unexpected mechanical terms, which may lead to oscillations on the load side. A double bi-quad filter structure, which can cancel the effects of compliant coupling and suppress wide-band resonance, is realized by inserting a virtual filter after the motor speed output. In practical implementation, the proposed control structure is composed of two bi-quad filters on both the forward and feedback paths of the speed control loop. Both of them collectively complete the wide-band resonance suppression, and the filter on the feedback path can solve the oscillation on the load side. Meanwhile, with this approach, in certain cases, the servo system can be more robust than with the single bi-quad filter method. A step by step design procedure is provided for the proposed algorithm. Finally, its advantages are verified by theoretical analysis and experimental results.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.50 no.2
• /
• pp.65-72
• /
• 2001

This paper presents the design and test results of a 10kVA single phase HTS transformer which is operating at 77K. Double pancake windings with BSCCO -2223 HTS tape and GFRP cryostat with room temperature bore are used in the transformer. Four double pan cake windings were used in pancake windings are connected in parallel to conduct the secondary current of 45.4A. the rated voltages of each winding are 440/220V. Numerical calculation using Finite Element Method was used to evaluated the performance of each arrangement. Considering the magnetizing reactance, leakage reactance, electrical insulation and the circulating current in low voltage winding which had two windings in parallel, HLLH arrangement was finally chosen. Estimation of the AC loss, magnetizing loss and self field loss, in the design stage, where effects of perpendicular field and parallel field are considered. Room temperature bore type cryostat has been constructed and its heat loss was measured.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.15 no.5
• /
• pp.315-320
• /
• 2022

In the case of a general spiral inductor, the orientation of the port is affected as it has an asymmetric structure. In this paper, double-layer spiral inductor that can have a symmetrical structure is proposed, and the simulation and frequency characteristics are analyzed. Compared to the conventional single-layer symmetrical inductor having an inductance of 3.9~4.2nH, the proposed double-layer symmetric spiral inductor has an inductance of 11~12nH in 0.3~1.2GHz frequency range, a quality factor of about 4.4 in 800MHz, and a self-resonant frequency of about 2.7~2.8GHz without changing the port. Compared to the general spiral inductor having a large difference depending on the port, it was confirmed that the influence on the port direction was small.

• Progress in Superconductivity and Cryogenics
• /
• v.20 no.4
• /
• pp.36-40
• /
• 2018

In this study, the electromechanical properties in Sn-Cu double layer stabilized GdBCO coated conductor (CC) tapes with and without external lamination under uniaxial tension were examined at 77 K and self-field. Their irreversible stress and strain limits were determined using a loading-unloading scheme based on different critical current ($I_c$) recovery criteria. The repeated tests were performed and statistical estimation was done to check the reproducibility depending on the criterion adopted in evaluating the electromechanical properties. From the results, it showed that the Sn-Cu double-layer stabilized CC tapes have the higher irreversible stress limit, but lower irreversible strain limit as compared to brass laminated ones. Through the repeated tests, it can be found that a small scattering of irreversible limits existed in both CC tape samples. Finally, similar strain sensitivity of $I_c$ in both CC tapes was obtained.

• The Journal of the Korea Contents Association
• /
• v.19 no.11
• /
• pp.482-498
• /
• 2019

The purpose of this study is to examine between the social isolation and smart phone addiction in elderly. Under this relationship, we investigated the double-mediation effects of self-regulation and social support. Research data were collected from 404 elderly in DaeJeon, South Korea. The final sample were 404 who fully responded. As a result of structural equation modeling, the social isolation of elderly significantly effected directly in smart phone addiction. Furthermore, self-regulation and social support effected the smart phone addiction indirectly through the double-mediation path. Based on the results of this study, the implications and future studies of the smart phone addiction of elderly are suggested.