• Title, Summary, Keyword: fluctuating waveform

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A Method to improve the input current waveform in a single phase Rectifier (단상 정류회로의 입력 파형 개선 방법)

  • Yu, Chul-Ro;Han, Woo-Yong;Lee, Su-Weon
    • Proceedings of the KIEE Conference
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    • pp.1005-1008
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    • 1992
  • This paper deals with a method to Improve the input current waveform in a single phase Rectifier. This method is based on the sophisiticated utilization of the auxiliary circuit consisting of two SCRs and a interphase reacter and the condenser necessary for reducing the fluctuating voltage in output side. The basic theories of the proposed system is treated, and its validity is verified with simulation.

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Adaptive Harmonic Control for DC Input Voltage Fluctuation of PWM Inverter (PWM인버터의 DC입력전달 맥동에 대한 고조파 적응제어)

  • 이윤종;임남혁
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.38 no.11
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    • pp.896-904
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    • 1989
  • PWM techniques which eliminate and reduce harmonics of output voltage in PWM Inverter driving System with fluctuating input volotage are described. First, harmonic factors are analyzed from harmonic equation of general PWM waveform and by examination of control possiblity of each factor, controllable factor is selected. Applying controllable factor to NPWM, PWM techniques using reference wave and carrier wave modulation are introduced. Actually, by the experiment applied with this strategy, the reduction of harmonics of output voltage is confirmed.

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Development of devices and methods for simulation of hurricane winds in a full-scale testing facility

  • Huang, Peng;Chowdhury, Arindam Gan;Bitsuamlak, Girma;Liu, Roy
    • Wind and Structures
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    • v.12 no.2
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    • pp.151-177
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    • 2009
  • The International Hurricane Research Center (IHRC) at Florida International University (FIU) is pursuing research to better understand hurricane-induced effects on residential buildings and other structures through full-scale aerodynamic and destructive testing. The full-scale 6-fan Wall of Wind (WoW) testing apparatus, measuring 4.9 m tall by 7.3 m wide, is capable of generating hurricane-force winds. To achieve windstorm simulation capabilities it is necessary to reproduce mean and turbulence characteristics of hurricane wind flows. Without devices and methods developed to achieve target wind flows, the full-scale WoW simulations were found to be unsatisfactory. To develop such devices and methods efficiently, a small-scale (1:8) model of the WoW was built, for which simulation devices were easier and faster to install and change, and running costs were greatly reduced. The application of such devices, and the use of quasiperiodic fluctuating waveforms to run the WoW fan engines, were found to greatly influence and improve the turbulence characteristics of the 1:8 scale WoW flow. Reasonable reproductions of wind flows with specified characteristics were then achieved by applying to the full-scale WoW the devices and methods found to be effective for the 1:8 scale WoW model.

Design of Double Digital Controller to Improve Performance for the Silent Discharging Ozonizer (무성방전 오조나이저의 성능개선을 위한 2중 디지털 제어기의 설계)

  • Park, Jee-Ho;Kim, Dong-Wan;Woo, Sung-Hoon;Roh, In-Bae;Woo, Jung-In
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.55 no.1
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    • pp.13-20
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    • 2006
  • In this paper, a control method of ozone generator for a tiny deodorizer is proposed, and also a cooling technique is described which is cooling down the flowing air gap into a silent discharger to $2[^{\circ}C]$ to generate ozone of high density and diffusing power. As the digital control system for this method, a double feedback loop is designed which detects the voltage and current of equivalent capacitor of the discharger and compensates for the poor power waveform caused by the noise at high discharging frequency. During the plant modeling of this system, computing time factor is considered as a unique parameter of the power system to improve the respond characteristics with regard to fluctuating load and to replenish the computing time delay of the controller. Through the experiment, sinusoidal input current for discharger can be acquired and all the effectiveness of this accurate control system over unstable ozone discharger are proved.

A Study on Cooling Effect and Power Control of a Mini Ozonizer (소형 오존발생장치의 전력제어와 냉각효과에 관한 연구)

  • Woo, Sung-Hoon;Park, Seung-Cho;Yoon, Sung-Yoon;Park, Jee-Ho;Woo, Jung-In
    • Journal of Korean Society of Environmental Engineers
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    • v.28 no.1
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    • pp.97-103
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    • 2006
  • In this paper, a control method of a mini ozone generator is proposed, and also a cooling technique is described which is cooling down the flowing air gap into a silent discharger to $2^{\circ}C$ to generate ozone of high density and diffusing power. As the digital control system for this method, a double feedback loop is designed which detects the voltage and current of equivalent capacitor of the discharger and compensates for the poor power waveform caused by the noise at high discharging frequency. During the plant modeling of this system, computing time factor is considered as a unique parameter of the power system to improve the transient responses with regard to fluctuating load and to replenish the computing time delay of the controller. Through the experiment, sinusoidal input current for discharger can be acquired and all the effectiveness of this accurate control system over unstable ozone discharger are proved.