• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.767-769
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• 1993

A multilevel PWM voltage source inverter, especially five-level one, is introduced to obtain a static var compensator(SVC) as a large scale power, source. In this paper, the three phase SVC is modeled using circuit DQ transformation and completely analyzed. Finally, through the experimental results from 5-kVA SVC, the validity of the analyses and the feasibility of the SVC system are shown for high power applications.

• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.93-94
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• 2015

본 논문에서는 전기자동차 응용을 위한 양방향 전류원 인버터를 제안한다. 본 논문에서는 회로 DQ변환에 의하여 얻어진 DC 등가회로를 바탕으로 3상 시스템의 DC 특성을 보이고 직류측 전류, 전압과 같은 변수에 대한 식을 유도한다. 본 논문에서는 시뮬레이션을 통하여 제안된 양방향 전류원 인버터가 전기자동차 응용에 적합하게 사용될 수 있음을 확인한다.

• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.111-112
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• 2015

MMC HVDC(Multi-level Modular Converter High Voltage Direct Current)는 현재 차세대 전력망으로써 각광을 받고 있고 그에 대한 연구가 활발하게 진행 중이다. 본 논문에서는 모듈형 멀티레벨 컨버터를 이용한 전압형 HVDC 시스템의 AC 전류제어기에 대하여 기술하고자 한다. 일반적으로 사용되는 회전변환을 통한 DQ전류제어와 PR제어를 사용하여 응답특성을 PSCAD/EMTDC를 통하여 비교 검증하고자 한다.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.419-420
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• 2020

본 논문에서는 전자기 교반 시스템용 2 상 직교하는 전원 공급 장치의 출력 전류 정상상태 오차를 줄일 수 있는 제어 기법을 제안하다. 2 상 직교하는 전원 공급 장치는 단상 풀브리지 인버터 2 대 대신 3 상 전압원 인버터 1 대를 사용하여 인버터의 레그 숫자가 줄어들고 인버터 스위치의 도통 손실이 감소한다. 본 논문에서는 회전 좌표계로의 변환(dq 변환)을 통해 출력전류 정상상태 오차를 0 으로 제어하는 기법을 제안한다. 본 논문에서는 제안하는 제어 기법의 유효성은 시뮬레이션을 통해 검증하였다.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.411-412
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• 2020

본 논문은 단상 영구자석 동기 전동기의 센서리스 제어방법을 제안한다. 단상 전류와 그에 직교하는 가상의 전류성분을 이용하여 dq 회전 좌표계에서 전류제어를 하고, d축 전류제어기의 출력을 이용하여 회전각을 추정한다. 제안된 방법은 구현이 매우 간단하다는 장점이 있다. 실험을 통해 제안된 방법의 성능을 확인하였다.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.4
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• pp.433-445
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• 2014

Single phase voltage source converter (VSC) is an important power electronic converter (PEC), including single-phase voltage source inverter (VSI), single-phase voltage source rectifier (VSR), single-phase active power filter (APF) and single-phase grid-connection inverter (GCI). As the fundamental part of large scale PECs, single-phase VSC has a wide range of applications. In the paper, as first, on the basis of the concept of the discontinuous pulse-width modulation (DPWM) for three-phase VSC, a new DPWM of single-phase VSR is presented by means of zero-sequence component injection. Then, the transformation from stationary frame (abc) to rotating frame (dq) is designed after reconstructing the other orthogonal current by means of one order all-pass filter. Finally, the presented DPWM based single-phase VSR is established analyzed and simulated by means of MATLAB/SIMULINK. In addition, the DPWMs presented by D. Grahame Holmes and Thomas Lipo are discussed and simulated in brief. Obviously, the presented DPWM can also be used for single-phase VSI, GCI and APF. The simulation results show the validation of the above modulation algorithm, and the DPWM based single-phase VSR has reduced power loss and increased efficiency.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.4
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• pp.548-554
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• 1997

The single crystal of $Mg_{0.16}Zn_{0.84}$Te:Co(Co:0.01 mole%) was grown by vertical Bridgman method. The crystal structure of $Mg_{0.16}Zn$_{0.84}$Te:Co and optical absorption properties of this compound were studied. The grown single crystal has a cubic structure and a lattice constant a=6.1422 $\AA$ were determined by X-ray diffraction. As a result of the optical absorption spectra of $Mg_{0.16}Zn_{0.84}$Te:Co, the intracenter transitions due to $Co^{2+}$ ions were detected for $A-band:^4A_2(^4F){\to}^4T_2(^4F),\; B-band:^4A_2(^4F){\to}^4T_1(^4F), C- band:^4A_2(^4F){\to}^4T_1(^4P)$.The charge transfer transition near the absorption edge was observed in the wavelength range of 550 to 770 nm. According to the crystal field theory, the crystal field parameter(Dq) and the Racah parameter(B) were determined.

• Journal of Korean Neurosurgical Society
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• v.46 no.6
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• pp.558-563
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• 2009

Objective : Moyamoya disease (MMD) is an uncommon cerebrovascular disorder, characterized by progressive occlusion at the terminal portion of the internal carotid artery. Incidence of the disease is high in East Asia and familial MMD accounts for about 15% of the disease. Although the pathogenesis is unknown, association of HLA class I or II alleles with MMD has been reported with conflicting results. We investigated whether there is a difference in HLA class II association between familial and non-familial forms of the disease. Methods : A total of 70 Korean children with MMD, including 16 familial cases (10 probands), and 207 healthy controls were studied. Among familial cases, only 10 probands were used for the HLA frequency analysis. High resolution HLA-DRB1 and DQB1 genotyping was performed using polymerase chain reaction (PCR)-sequence specific oligonucleotide hybridization and PCR-single strand conformation polymorphism methods. Results : The phenotype frequencies of HLA-DRB1*1302 (70.0%) and DQB1*0609 (40.0%) were significantly increased in familial MMD compared to both controls [vs. 15.5%, corrected p ($p_c$) = 0.008, odds ratio (OR) = 12.76; vs. 4.3%, $p_c\;=\;0.02$, OR = 14.67] and non-familial MMD patients (vs. 14.8%, $p_c\;=\;0.02$, OR = 13.42; vs. 1.9%, $p_c\;=\;0.02$, OR = 35.33). The frequencies of DRB1 and DQB1 alleles in non-familial MMD patients were not significantly different from those in controls. Conclusion : Our findings suggest that the genetic polymorphism of HLA class II genes or other closely linked disease relevant gene(s) could be a genetic predisposing factor for familial MMD.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.2
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• pp.152-161
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• 2011

An interior permanent magnet synchronous motor(IPMSM) has been applied to the electric vehicle due to its high efficiency, compact volume, and wide operating speed ranges. This paper presents the analysis of the flux weakening operating regions at high speeds for the IPMSM that has back emf harmonics. The effect of the back emf harmonics on the motor speed and the maximum torque is analyzed. Also the dq currents for maximum torque operation under the voltage and the current limit conditions are analyzed. The conventional analysis and the presented analysis for the flux weakening operating regions are compared and the maximum torque - speeds characteristics for both analysis are verified through the experiment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.3
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• pp.476-482
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• 2006

The aim of this work was to perform the screening and identification of the bacterium, MK-15 having the activity of fibrinolytic enzyme for the commercial use. Initially, strain MK-15 was enriched and isolated from naturally fermented soybean. Morphological and various physiological characteristics of the strain MK-15 was examined. The activity of fibrinolytic enzyme derived from supernatants of test culture MK-15 was performed by fibrin plate method for solid fibrinolytic activity. As the result, the fibrinolytic activity of MK-15 grown on the soybean media was about 2.7 times greater than that of plasmin used as stardard. 16S rRNA analyses revealed that strain MK-15 was 99.9% similar to Bacillus subtilis species cluster, and the bacterium was designated as Bacillus sp. MK-15. Strain MK-15 was registered in GenBank as [DQ163021].