• 제목/요약/키워드: 오봉환

검색결과 77건 처리시간 0.033초

디지틀 셀룰러 이동통신 시스팀의 기능에 관한 연구

  • 오봉환;노경호;이혁재
    • 전자통신동향분석
    • /
    • 제3권3호
    • /
    • pp.37-46
    • /
    • 1988
  • 이동 통신 수요의 급증에 따른 용량 부족 및 Roaming 서비스의 확대 필요성, 향후 ISDN 서비스 요구등에 부응하여 선진 각국에서는 이미 디지틀 셀룰러 이동 통신 시스팀을 개발해 오고 있다. 본 고에서는 특히 유럽 시스팀을 중심으로 디지틀 셀룰러 시스팀의 요건, 서비스, 통신망 등을 분석하여 향후 국내 시스팀 설계에 도움을 주고자 하였다.

0.7MJ SMES의 개념설계 (Conceptual design of 0.7MJ superconducting magnetic energy storage)

  • 오봉환;진홍범;류강식;류경우
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 1996년도 하계학술대회 논문집 A
    • /
    • pp.202-204
    • /
    • 1996
  • A superconducting magnetic energy storage device(SSD) system has being developed to provide power to industrial electric loads subjected to short term voltage disturbances. In this paper, the results of the conceptual design of SSD system are described.

  • PDF

견인시스템에 대한 점착특성 시험장치 (Wheel-Railway Adhesion Characteristics Experiment Machine on Traction System)

  • 이사영;오봉환;이복구;김봉희;전지용;김길동;박현준
    • 전력전자학회:학술대회논문집
    • /
    • 전력전자학회 1999년도 전력전자학술대회 논문집
    • /
    • pp.130-133
    • /
    • 1999
  • It is one of the most effective methods for improving the performance of electric railway vehicles to make better the wheel-railway adhesion characteristics. The purpose of this paper is to develop the equivalent reduction machine to experiment on the adhesion system. The experiment system makes it possible to change the wheel-rail adhesion force with various adhesion parameters, and therewith to test the adhesion control system with the reduction machine in a laboratory.

  • PDF

변조율이 큰 전압형 컨버터의 PWM 변조방법 (PWM Method of Voltage Type Converters with Large Modulation Ratio)

  • 이사영;오봉환;김봉희;박현준;김길동;이승학;이미영
    • 전력전자학회:학술대회논문집
    • /
    • 전력전자학회 1998년도 전력전자학술대회 논문집
    • /
    • pp.287-290
    • /
    • 1998
  • This paper presents PWM method which modulates two third period only during one cycle of power converter. This method is compared with the conventionl sinusoidal modulation method applying to the power converter with large capacity necessitating low switching frequency. The presented modulation method enables to reduce power semiconductor rating, minimize switching loss, and improve the current wave form.

  • PDF

태양전지 전류에 의한 계통연계형 태양광발전시스템의 최대출력 제어법 (Maximum Power Point Tracking Control of Photovoltaic System by using Current Solar Cell)

  • 박인덕;성낙규;김대균;이승환;오봉환;김성남;한경희
    • 전력전자학회:학술대회논문집
    • /
    • 전력전자학회 1998년도 전력전자학술대회 논문집
    • /
    • pp.109-112
    • /
    • 1998
  • A step down chopper and PWM current source inverter is used for the connection between the PV array and the utility. This paper proposes chopper is controlled for the dc reactor decrease and PWM current source inverter is controlled to keep the output power at the maximum point for the PV. The PV current only is measured and employed for the power calculation combining the control parameter of the PWM current source inverter.

  • PDF