• 제목/요약/키워드: engineering technique

검색결과 22,362건 처리시간 0.056초

공진형 직류 링크단을 이용한 유도전동기의 예측형 전류 제어 (A Novel Predictive Current Control of Induction Motor Using Resonant DC Link Inverter)

  • 오인환;문건우;김성권;윤명중
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 1996년도 하계학술대회 논문집 A
    • /
    • pp.567-570
    • /
    • 1996
  • A predictive current control technique for an induction motor employing a resonant DC link inverter is proposed to overcome the disadvantage of the current regulated delta modulation(CRDM) which was employed to control the resonant DC link inverter. The discrete model of an induction motor and estimation of back EMF are investigated and a novel predictive current control technique is newly developed based on this discrete model and estimated back EMF. Using the proposed control technique, the minimized current ripple with reduced offset can be obtained. The usefulness of the proposed technique is verified through the computer simulation.

  • PDF

복합동반쓰기를 사용하는 디스크 시스템의 성능 평가 (Performance Evaluations of Hybrid Write-Piggybacking Technique for Disk System)

  • 장윤석;김홍일;김국보
    • 한국정보처리학회논문지
    • /
    • 제3권4호
    • /
    • pp.983-991
    • /
    • 1996
  • 본 논문에서는 디스크캐쉬 관리 기법의 하나인 동반쓰기 기법을 개선한 복합동반 쓰기 기법을 제안하고 그 성능을 평가하였다. 제안된 기법의 성능 평가를 위하여 디스 크 시스템을 모델화 하여 실제 디스크시스템에 근접한 시뮬레이션 모델을 구현하고 trace-driven 시뮬레이션을 수행하였다. 시뮬레이션의 결과 본 연구에서 제안된 복합 동반쓰기 기법이 기존의 동반쓰기 기법에 비하여 우수한 성능을 나타냄을 증명하였다.

  • PDF

Digital Control of a Power Factor Correction Boost Rectifier Using Diode Current Sensing Technique

  • Shin, Jong-Won;Hyeon, Byeong-Cheol;Cho, Bo-Hyung
    • Journal of Power Electronics
    • /
    • 제9권6호
    • /
    • pp.903-910
    • /
    • 2009
  • In this paper, a digital average current mode control using diode current sensing technique is proposed. Although the conventional inductor current sensing technique is widely used, the sensed signal of the current is negative. As a result, it requires an additional circuit to be applied to general digital controller ICs. The proposed diode current sensing method not only minimizes the peripheral circuit around the digital IC but also consumes less power to sense current information than the inductor current sensing method. The feasibility of the proposed technique is verified by experiments using a 500W power factor correction (PFC) boost rectifier.

전자 스페클 패턴 간섭계를 이용한 형상 측정 (Surface contouring using Electronic Speckle Pattern Interferometry)

  • 김계성;유원재;강영준
    • 한국정밀공학회:학술대회논문집
    • /
    • 한국정밀공학회 1995년도 추계학술대회 논문집
    • /
    • pp.397-401
    • /
    • 1995
  • ESPI(Electronic Speckle Pattern Interfermetry) is an optical technique to measure surface deforamtion of engineering components and materials in industrial ares. This optical method is capable of providing full-field results with high spatial resolution, high speed and is the non-contact technique. One of important application aspects using electronic speckle pattern interferometry is to generate contours of a diffuse object in order to provide data for 3-D shape analysis and topography measurement. The contouring method by modified dual-beam speckle pattern interferometry is proposed. We introduce a shift of the illumination beams through optical fiber in order to obtain the contour fringe patterns. The speckle pattern correlation technique is suitable for providing measurement range from millimeters to several centimeters. The complete geometric analysis of the contoretical and experimental results are obtained.

  • PDF

Compensation of Power Fluctuations of PV Generation System by SMES Based on Interleaving Technique

  • Kim, Seung-Tak;Park, Jung-Wook
    • Journal of Electrical Engineering and Technology
    • /
    • 제10권5호
    • /
    • pp.1983-1988
    • /
    • 2015
  • This paper proposes the enhanced application of superconducting magnetic energy storage (SMES) for the effective compensation of power fluctuations based on the interleaving technique. With increases in demand for renewable energy based photovoltaic (PV) generation system, the output power fluctuations from PV generation system due to sudden changes in environmental conditions can cause serious problems such as grid voltage and frequency variations. To solve this problem, the SMES system is applied with its superior characteristics with respect to high power density, fast response for charge and discharge operations, system efficiency, etc. In particular, the compensation capability is effectively improved by the proposed interleaving technique based on its parallel structure. The dynamic performance of the system designed using the proposed method is evaluated with several case studies through time-domain simulations.

4M 위험성평가 기법을 이용한 앗차사고의 효과적인 발굴기법 (Effective Detection Technique of Near Miss using 4M Risk Assesment Methodology)

  • 서성화;원종일;우흥식
    • 한국안전학회지
    • /
    • 제27권5호
    • /
    • pp.164-170
    • /
    • 2012
  • In this study, a new technique for detecting near miss using 4M risk assessment method is suggested. Until now, the safety education with instances of near miss has just been progressed in most industrial settings, without any systematic guideline. By menas of appling 4M risk assessment method, the organized technique, which could effectively manage the fundamental prevention of industrial accident in advance, is developed. The organized technique of near miss-management suggested in this study will take an effective role in basically expanding the application of risk assessment method, as well as in contributing the activity of zero-accident as a safety guideline in hazardous workshops.

부분적 경사자계를 이용한 국부자기공명 영상촬영기법 (Localized MR Imaging Technique by Using Locally-Linear Gradient Field)

  • 양윤정;이종권;정성택;조장희;오창현
    • 대한의용생체공학회:학술대회논문집
    • /
    • 대한의용생체공학회 1995년도 추계학술대회
    • /
    • pp.247-249
    • /
    • 1995
  • A new localized imaging technique of reduced imaging time using a locally-linear gradient is proposed. Since most fast MR imaging methods need the whole k-space data corresponding to the whole imaging area, there are limitations in reducing the minimum imaging time. The imaging method proposed in this paper uses a specially-made gradient coil generating a local ramp-shape field and uniform field outside of the imaging area. Conventional imaging sequences can be used without any RF/gradient pulse sequence modifications. The proposed localized imaging technique has been implemented on a 2.0 Tesla whole-body system at KAIST and the imaging results show the utility of the proposed technique.

  • PDF

라프셋 이론이 적용에 의한 ID3의 개선 (Improvement of ID3 Using Rough Sets)

  • 정홍;김두완;정환묵
    • 한국지능시스템학회:학술대회논문집
    • /
    • 한국퍼지및지능시스템학회 1997년도 추계학술대회 학술발표 논문집
    • /
    • pp.170-174
    • /
    • 1997
  • This paper studies a method for making more efficient classification rules in the ID3 using the rough set theory. Decision tree technique of the ID3 always uses all the attributes in a table of examples for making a new decision tree, but rough set technique can in advance eleminate dispensable attributes. And the former generates only one type of classification rules, but the latter generates all the possibles types of them. The rules generated by the rough set technique are the simplist from as proved by the rough set theory. Therefore, ID3, applying the rough set technique, can reduct the size of the table of examples, generate the simplist form of the classification rules, and also implement an effectie classification system.

  • PDF

NEW METHODS OF THE GROWING COMPLICATED SHAPED SAPPHIRE PRODUCTS: VARIABLE SHAPING TECHNIQUE AND LOCAL DYNAMIC SHAPING TECHNIQUE

  • Borodin, V.A.;Sidorov, V.V.;Steriopolo, T.A.
    • 한국결정성장학회:학술대회논문집
    • /
    • 한국결정성장학회 1999년도 PROCEEDINGS OF 99 INTERNATIONAL CONFERENCE OF THE KACG AND 6TH KOREA·JAPAN EMG SYMPOSIUM (ELECTRONIC MATERIALS GROWTH SYMPOSIUM), HANYANG UNIVERSITY, SEOUL, 06월 09일 JUNE 1999
    • /
    • pp.209-225
    • /
    • 1999
  • Detailed description of the crystal growth methods permitting one to obtain complicated shape crystals from the melt is given. The variable shaping technique provides the growth of crystals with a discrete altering cross-section configuration during crystallization. The dynamic local shaping technique enables one to grow items with a continuous alteration of the side surface profile by a preset program.

  • PDF

A New COG Technique Using Solder Bumps for Flat Panel Display

  • Lee, Min-Seok;Kang, Un-Byoung;Kim, Young-Ho
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 한국정보디스플레이학회 2003년도 International Meeting on Information Display
    • /
    • pp.1005-1008
    • /
    • 2003
  • We report a new FCOG (flip chip on glass) technique using solder bumps for display packaging applications. The In and Sn solder bumps of 40 ${\mu}m$ pitches were formed on Si and glass substrate. The In and Sn bumps were bonded at 125 at the pressure of 3 mN/bump. The metallurgical bonding was confirmed using cross-sectional SEM. The contact resistance of the solder joint was 65 $m{\Omega}$ which was much lower than that of the joint made using the conventional ACF bonding technique. We demonstrate that the new COG technique using solder bump to bump direct bonding can be applied to advanced LCDs that lead to require higher quality, better resolution, and lower power consumption.

  • PDF