• Title/Summary/Keyword: distorted power

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Computation of Distortion Power Using Complex THD (THD의 복소 성분을 이용한 고조파 왜곡 환경에서의 전력 계산)

  • 최종욱;장길수
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.53 no.7
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    • pp.389-396
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    • 2004
  • This paper introduces a new algorithm to calculate distortion power using complex THD(Total Harmonic Distortion) index. The proposed algorithm involves FFT(Fast Fourier Transform) to compute real and imaginary THDs of voltage and current. Case studies are presented to show the availability of the proposed method.

Control Algorithm of Single Phase Active Series Voltage Compensator Considering Distorted Power Conditions (왜형된 전원조건을 고려한 단상 능동 직렬형 전압 보상기의 제어 알고리즘)

  • Kim, Jung-Kun;Jung, Young-Gook;Kim, Young-Cheol;Lim, Young-Cheol
    • Proceedings of the KIEE Conference
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    • pp.259-262
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    • 2001
  • 본 연구에서는 과도상태와 정상상태에서 고조파 보상특성이 우수한 순시전력이론을 단상에 적합하게 수정한 후 순시전압강하 보상 기능을 갖는 단상하이브리드형 직렬 능동전력필터의 제어에 적용하였다. 제안된 알고리즘은 전원전압이 순간적으로 왜형 및 강하되더라도 비선형 부하에 인가되는 전압은 항상 일정치를 갖는 정현파로 제어 가능하며 동시에 전원전류의 고조파와 기본파 무효전류도 보상 가능하다. 정상상태와 과도상태에서 전력전자전용 시뮬레이터인 PSIM에 의해 제안된 이론의 타당성을 입증하였다.

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Instantaneous Power Theory Considering Three Phase Unbalanced/Distorted Power Conditions (3상 불평형 및 왜형 전원조건을 고려한 순시전력이론)

  • Jung, Kwang-Sik;Jung, Young-Gook;Cho, Jae-Yun;Lim, Young-Cheol
    • Proceedings of the KIEE Conference
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    • pp.267-270
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    • 2001
  • 본 연구에서는 3상 비 대칭이며 왜형된 전원 시스템하에도 탁월한 고조파 및 무효전력 보상 특성을 갖는 순시전력이론을 다루고 있다. 제안된 알고리즘은 불평형 전원전압의 정상분을 검출하고 이를 바탕으로 순시보상전력을 계산한다. 전원전압이 왜형되고 블평형인 정상상태와 과도상태에서 전력전자전용 시뮬레이터인 PSIM에 의해 정상분 전압 검출이 없는 종전의 순시전력이론과 제안된 이론을 비교하였으며 그 타당성을 검토하였다.

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Instantaneous Amplitude and Frequency Estimator Using the Symmetric Higher Order Differential Energy Operator (대칭구조를 갖는 고차의 미분 에너지함수를 이용한 순간진폭 및 순간주파수 추정기)

  • Iem, Byeong-Gwan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.8
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    • pp.1193-1198
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    • 2012
  • An instantaneous amplitude (IA) estimator using the symmetric higher order differential energy operator is proposed. The amplitude estimator and the instantaneous frequency (IF) estimator based on the symmetric higher order differential energy operator coincide with the analyzed signal in time, and they show better estimation results than the IA and IF based on the higher order differential energy operator. Various IF and IA estimators are applied to AM-FM signals for the performance comparison. Among the IF and IA estimators, the IF and IA estimators based on the symmetric higher order energy operator show the best estimation accuracy. Then, the IA and IF estimators are applied to the distorted power line signal to show their usefulness as power disturbance detectors.

A Rejection of Harmonic Ripples for d-q Transformation (d-q 변환에서의 고조파 맥동 제거)

  • Choi, Nam-Yerl;Lee, Chi-Hwan
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.12
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    • pp.83-87
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    • 2015
  • This paper presents a simple notch filter, which is so suitable for three-phase unbalanced and distorted power line. In the d-q synchronous transformation, three-phase unbalanced and distorted voltages generate lots of ripple voltages on d-q axes. The ripples make disturbances on controllers such as PLL of phase tracking. Unbalanced state makes ripple of double the frequency of power line. Odd harmonics 5th and 7th on the line make even 4th and 6th ripples on d-q axes due to the rotating reference frame, respectively. Cascaded two comb filters, delay lines 1/4T and 1/8T, are adopted for the ripple rejection. The filter rejects harmonics 2nd, 4th, 6th, 10th and so on. They are very effective to remove the ripples of both unbalance and distortion. The filter, implemented by two FIFOs on an experimental system, is adopted on a PLL controller of power line phase tracking. Through the simulation and experimental results, performance of the proposed comb filter has been validated.

Graphical Representation of the Instantaneous Compensation Power Flow for Single-Phase Active Power Filters

  • Jung, Young-Gook
    • Journal of Electrical Engineering and Technology
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    • v.8 no.6
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    • pp.1380-1388
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    • 2013
  • The conventional graphical representation of the instantaneous compensation power flow for single-phase active power filters(APFs) simply represents the active power flow and the reactive power flow which flowing between the power source and the active filter / the load. But, this method does not provide the information about the rectification mode and the compensation mode of APFs, especially, the loss for each mode was not considered at all. This is very important to understand the compensation operation characteristics of APFs. Therefore, this paper proposes the graphical representation of the instantaneous compensation power flow for single-phase APFs considering the instantaneous rectification mode and the instantaneous inversion mode. Three cases are verified in this paper - without compensation, with compensation of the active power 'p' and the fundamental reactive power 'q', and with compensation of only the distorted power 'h'. To ensure the validity of the proposed approach, PSIM simulation is achieved. As a result, we could confirm that the proposed approach was easy to explain the instantaneous compensation power flow considering the instantaneous rectification mode and the instantaneous inversion mode of APFs, also, Total Harmonic Distortion(THD)/Power Factor (P.F) and Fast Fourier Transform(FFT) analysis were compared for each case.