• 한국전기전자재료학회논문지
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• 제33권3호
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• pp.225-230
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• 2020

Recently, with the miniaturization of GIS, there is a need for the miniaturization of spacers as accessories. Miniaturized spacers make it difficult to secure adequate insulation distances, resulting in a more concentrated electric field at the triple junction of high-voltage (HV) conductor-insulator (spacer)-insulation gas (SF₆), which is a weakness in GIS. Therefore, by introducing a new concept design technology, functionally graded material (FGM), which is recently applied to various materials and parts industries, three-dimensional control of the dielectric constant distribution in a spacer can be expected to alleviate triple-junction electric field occupancy and improve insulation performance. In this study, we propose an optimized model using NSGA-II to optimize the permittivity distribution of FGM applied spacer.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.31-33
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• 2002

This paper is presents dynamic analysis of slotless PM linear synchronous motor using 3-D analytical method and improvement of controllability using PI control system. In oredr to calculate dynamic characteristic, back-EMF waveform and inductance are caculated by PM's magnetic field and winding's magnetic filed respectively. PMLSM simulated by PI control system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.612-615
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• 1996

In the continuous casting process, molten metal contacts the mold wall and the molten metal surface is subject to the mold oscillation. The mold oscillation results in the oscillation marks on the surface of solidified steel, which has undesirable effects on the quality of slabs. In order to reduce the oscillation marks by achieving soft contact of molten metal with the mold surface, alternating magnetic field is applied to the surface of molten metal. However, if the magnetic field strength becomes too strong, the melt flow induced by the magnetic field. causes the instability of the molten metal surface, which has also the bad influence on the slab quality. Therefore, it is very important to choose the optimal position of the inductor coil and the optimal level of electric power to minimize the surface defects. In the present work, as a first step toward the optimization problem of the process, numerical studies are performed to investigate the effects of coil position and the electric power level on the meniscus shape and the flow field. As numerical tools, the boundary integral equation method(BIEM) is used for the magnetic field analysis and the finite difference method (FDM) with orthogonal grid generation is used for the flow analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.140-142
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• 2008

Thrust ripples in Permanent Magnet Linear Motor(PMLSM) are mainly generated by cogging force. Cogging force caused by the interaction between the iron core and the Permanent Magnet(PM), and end effect. This paper has proposed a control method for thrust ripples suppression and design of one-chip proceeding digital controller using TMS320LF2407. This control method is realized by Field Oriented Control(FOC) adding to current compensation. The effectiveness of proposed control method is verified by experimentation comparing between the compensation and non-compensation.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.141-142
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• 2008

According as USN's application field is magnified, various results are appearing. Efforts to apply this results in life are progressing. In car field, is used in control that level of significance is less. In home network, is used in a household electric appli-ance control and electric lamp control, security etc.. In factory, is used in process control, and is used in various application because is involved with RFID leader recently. In this paper, patient's status monitoring, USN use wish to. Because USN can utilize existent network, it is system that can transmit various data as that change passed information.Wish to send information that get in health-care board. Information that can get in health-care board is blood pressure, blood sugar, stroke, SPO2, ECG, the activity amount, position. Also, wish to forecast use possibility to involved various service, silver industry with database.

• Current Applied Physics
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• 제18권11호
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• pp.1201-1204
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• 2018

The effect of electric current pulses on a sub-100 nm magnetic bubble state in a symmetric Pt/Co multilayer was directly observed using a full-field transmission soft X-ray microscope (MTXM). Field-induced evolution of the magnetic stripe domains into isolated bubbles with their sizes down to 100 nm was imaged under varying external magnetic fields. Electric current pulses were then applied to the created magnetic bubbles, and it was observed that the bubbles could be either created or annihilated by the current pulse depending on the strength of applied magnetic field. The results suggest that the Joule heating plays a critical role in the formation and/or elimination of the bubbles and skyrmions. Finally, the schematic phase diagram for the creation and annihilation of bubbles is presented, suggesting an optimized scheme with the combination of magnetic field and electric current necessary to utilize skyrmions in the practical devices.

• Journal of Power Electronics
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• 제11권2호
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• pp.120-131
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• 2011

This paper proposes two control strategies for the bidirectional Z-source inverters (BZSI) supplied by batteries for electric vehicle applications. The first control strategy utilizes the indirect field-oriented control (IFOC) method to control the induction motor speed. The proposed speed control strategy is able to control the motor speed from zero to the rated speed with the rated load torque in both motoring and regenerative braking modes. The IFOC is based on PWM voltage modulation with voltage decoupling compensation to insert the shoot-through state into the switching signals using the simple boost shoot-through control method. The parameters of the four PI controllers in the IFOC technique are designed based on the required dynamic specifications. The second control strategy uses a proportional plus resonance (PR) controller in the synchronous reference frame to control the AC current for connecting the BZSI to the grid during the battery charging/discharging mode. In both control strategies, a dual loop controller is proposed to control the capacitor voltage of the BZSI. This controller is designed based on a small signal model of the BZSI using a bode diagram. MATLAB simulations and experimental results verify the validity of the proposed control strategies during motoring, regenerative braking and grid connection operations.

• 한국전자통신학회논문지
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• 제16권5호
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• pp.845-850
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• 2021

본 연구에서는 전기 자동차(EV : Electric Vehicle) 파워트레인의 에너지 변환 특성과 설계를 수행하였다. 그리고 EV 파워트레인의 동력원으로서 영구자석 매입형 동기 모터(IPMSM : Interior Permanent Magnet Synchronous Motor)를 대상으로 하였으며 제어를 수행하였다. IPMSM을 구동하기 위해서는 두 가지 영역인 일정한 토크와 일정한 출력(약계자) 영역이 사용되며, IPMSM을 위한 제어 시스템의 설계는 d-q 레퍼런스 프레임(벡터 제어)을 바탕으로 구성하였다. IPMSM의 두 영역에서 나타나는 모터 토크의 정적 특성을 결정하기 위해 IPMSM의 토크제어 시스템과 d축 전류 제어 시스템을 제안 및 구현하였다. 특성해석을 위해서 Matlab-Simulink 소프트웨어를 사용하였다. 최종적으로 실제 차량 사양을 기준으로 EV 차량 레벨 조건으로 변경하여 파워트레인 모델에 IPMSM을 적용하였으며 제안된 제어 시스템의 시뮬레이션 결과를 수행했고 특성을 분석하였다.

• 한국전자파학회논문지
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• 제8권1호
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• pp.83-93
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• 1997

본 논문은 고전압 실험실에서 시변성 전자계의 측정 및 평가에 관한 것으로 전자적 외란은 주로 전력장비의 지락고장 및 개폐조작에 의해 기인되며, 전자회로와 제어장비틀은 전자방해작용에 매우 민감하다. 주어진 전자환 경에 대한 전자방해작용의 레벨을 평가하는 것은 필수적이다. 전계는 40 Hz-2oo MHz 범위의 대역폭을 갖는 전계센서로 관측되었으며, 시변성 자계는 출력이 입사신호에 직접적으로 비례하는 루프형 센서로 측정되었다. 또한 진동성 과도전류와 차단파 임펄스전압에 의해 유도된 전자방해작용의 레벨파 전자 차폐의 외함설계에 관한 정보를 주는 사변성 전자계의 주파수 성분을 고속프리에변환으로 분석하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전력기술부문
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• pp.122-124
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• 2008

Korea Electric Power Research Institute has being carried out an IEC 61580 communication service test on IED trial products developed related to power IT project "The verification of Performance of the Substation Automation System and Its Field Test". This paper describes control testing, one of the IEC 61850 conformance testing items, which consists of DO, enhanced DO, SBO and enhanced SBO with a number of test cases.