• Title/Summary/Keyword: 플리커현상

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A Study on the Outages Due to Voltage Expanding in Closing High Voltage Capacitor (고압 커패시터 투입시 전압확대에 따른 사고 사례 연구)

  • Cho, Nam-Hoon;Jung, Jum-Soo;Park, Yong-Woo;Ha, Bok-Nam;Lee, Hyung-Ho
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.9
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    • pp.94-102
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    • 2008
  • Capacitor switching is essential for the economic operation and proper voltage control of KOREA electric utility distribution system. Voltage transients produced by capacitor switching (around 2.0 per unit at substation and 2.5 or less per unit at customer site, and lasting less then 1[ms]) do not have the magnitude or duration to interfere with the operation of computers, but they do disrupt the operation of adjustable speed drivers. The result of our research, ASD manufacturers should learn from the computer industry and design products that will operate satisfactory In the electrical envelopment in which they will be placed. In this case history, the inductors on the input to ADSs in order to prevent nuisance tripping from capacitor switching(and other causes within the apartment) proved to be an effective, low-cost solution.

A Study on the Driving of Ballast for 35W Class (T5 Class) Fluorescent Lamp using a Piezoelectric Transformer Characteristic (압전 변압기 특성을 이용한 35W급(T5급) 형광등용 안정기 구동에 관한 연구)

  • Hwang, Lark-Hoon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.3
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    • pp.638-644
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    • 2008
  • It is required small size electronic ballast to fullfill the design philosophy of miniaturizing in the application of slim lamps. However, the traditional magnetic ballasts operated at 50-60Hz have been suffered from noticeable flicker, high loss, large crest factor and heavy weight. In this study, in order to solve these problems, It was proposed for driving 35W Class fluorescent lamp in the new type of electronic ballast, which is composed of rectifier, active power factor corrector, series resonant half bridge inverter and piezoelectric transformer. A 35W class(T5 class) fluorescent lamp is driven to successful by the fabricated ballast with piezoelectric transformer. Experimental results, It is proposed to driving the lamp using a electronic ballast at operating frequency of $75{\sim}79kHz$ approximatively. It is operated after for 25 min that were obtained good results of the input power factor of 0.95 and efficiency of 86%, respectively.

Comparison of Main Circuit Type Characteristics of LED Driver for Output Ripple Reduction (출력 리플 저감을 위한 LED 드라이버의 주회로 방식 특성 비교)

  • Park, Dae-Su;Kim, Tae-Kyung;Oh, Sung-Chul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.3
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    • pp.491-499
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    • 2019
  • Recently, there has been increasing demand for power quality in power supply devices. The IEC 61000-3-2 standard requires that the AC / DC power supply for lighting meet the specifications for the power factor (PF) and total waveform distortion (THD). In addition, advanced countries in Europe are regulating the ripple rate as 15 ~ 30% for the flicker phenomenon caused by the change in the amount of foot energy due to the change in current of the output terminal. Therefore, domestic standards and regulations are being updated. This study adopted the Flyback converter to satisfy the PFC standard, and has the circuit first and second insulation function. To reduce the low frequency ripple of the LED current, Flyback, Coupled Inductor, LC parallel resonance filter, LLC resonance filter, and Cuk were simulated by PSIM to mimic each LED driving circuit. A coupled LC resonant circuit with a coupled inductor on the primary side and LC resonance on the secondary side was also proposed for output side ripple reduction.