• 제목/요약/키워드: Harmonic Distortion

검색결과 735건 처리시간 0.027초

온라인 고조파 해석 지수의 개발 (On-line Harmonic Distortion Index for Power Quality Assessment)

  • 장길수;송화창;이병준
    • 대한전기학회논문지:전력기술부문A
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    • 제50권8호
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    • pp.373-378
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    • 2001
  • This paper introduces a new online index to quantify the harmonic distortion. The proposed index based on VI product can represent the harmonic distortion of both voltage and current, and it includes the effect of interharmonic distortion. Also, the new index is suitable to online harmonic distortion evaluation since it only requires the r.m.s. (root mean square) value and fundamental frequency value of the signals. Case studies are presented to show the availability of the proposed index using the comparison with the THD (Total Harmonic Distortion).

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전기 추진선을 위한 고조파 제어 사례 연구 (Harmonic Distortion Control for Electric Propulsion)

  • 김주완;이충열;서근경
    • 대한조선학회 특별논문집
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    • 대한조선학회 2008년도 특별논문집
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    • pp.38-45
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    • 2008
  • The application of the electric propulsion system to the vessels has recently become common due to the latest technology for controlling the electric motors with variable speed. However it has been found that harmonic distortion exists in the electric propulsion system, which consists of an electric motor, a converter and an inverter, and this harmonic distortion has a harmful effect on the system. In this paper, the definition of the harmonic distortion and problems caused by the harmonic distortion in the electric propulsion of the vessels are introduced and the practical solutions for the problems are investigated.

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회귀 최소 자승법을 이용한 고조파 발생원 추정 연구 (Estimation of Harmonic Sources in a Power System using Recursive Least-Squares Technique)

  • 한종훈;이계병;박창현;장길수
    • 전기학회논문지
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    • 제60권9호
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    • pp.1639-1645
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    • 2011
  • A technique to allocate responsibilities among the interested parties in electric power system with harmonic voltage distortion at the point of common coupling (PCC) has been presented. The recursive least-squares technique has been used to estimate the parameters of the Thevenin equivalent load model. The validity of the technique has been verified using a simulation which considered the voltage waveform distortion at the PCC between the utility and two industrial consumers. With the estimated data from the measured voltage and current waveform at the PCC, the individual contributions to the distortion of voltage waveform at an interested harmonic frequency have been calculated and could provide a flexible solution to identify the source of harmonic pollution in distribution systems.

직접 방사형 스피커의 비선형 고조파 왜곡 보상 제어기의 설계 (Controller design for compensation of nonlinear harmonic distortion in direct-radiator loudspeakers)

  • 김윤선;박영진
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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    • pp.399-402
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    • 1996
  • The electrodynamic loudspeakers should have a wide dynamic range to reproduce various sound levels. When the input signal is small, the radiated sound from the loudspeaker is not so much distorted. However, for large input signal with low frequency component the radiated sound is significantly distorted due to the nonlinearities of the loudspeaker. The suspension, damping, and magnetic flux of loudspeaker are the main sources of the nonlinearity. Such electromechanical parameters related to harmonic distortion have been represented by a polynomial model for diaphragm displacement, while each of the polynomial coefficient is evaluated by using the principle of harmonic balance experimentally. Based on the polynomial model, we designed a compensator for nonlinear harmonic distortion of direct radiator loudspeaker. Than observer is used to estimate the displacement of the loudspeaker diaphragm, which is rather difficult to measure directly in the conventional setting. The usefulness of the designed compensator is demonstrated by numerical simulations. Simulation results show about 30db decrease at the second and third higher harmonic distortions. We carry out an experiment on speaker to verify designed controller and nonlinear observer.

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특수수용가의 고조파전압 왜형현황과 고조파 관리 방안 (Harmonic Distortion Level of Special loads and Method of Harmonic Distortion Management)

  • 황치우;성기철
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1997년도 하계학술대회 논문집 D
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    • pp.875-877
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    • 1997
  • Due to the development of electric energy conversion technology and need for energy saving most of the electric machinery and equipments are using power semiconductor switching elements, On the contrary semiconductor switching device is more sensitive to the voltage instability and voltage distortion. In order to manage the voltage distortion following foundation should be settled down in advance. First, reasonable and objective technical guidelines should be established. Second, monitoring network for power quality should be operated. In this paper measurement results of the harmonic distortion of the special loads are given and method for harmonic pollution management is discussed.

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Comparison of the harmonic reduction by using harmonic passive fitters and technique of intervene firing method at the pulse of the 6-pulse phase controlled converter.

  • Wongtongdee, Surached W.;Laohasongkram, Pipat
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2005년도 ICCAS
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    • pp.782-785
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    • 2005
  • This article introduces technique to reduce harmonic by using the $5^{th}$ and $7^{th}$ harmonic tune filter and line reactor in the comparison to the technique of intervening firing method at the pulse of the 6-pulse phase-controlled converter in every 1/6 period. The design of the technique introduced in this article is to reduce the harmonic distortion of the current and the voltage resulted from three-phase thyristor phase-controlled converter. The waveform obtained from the experiment was analyzed on the spectrum of the current, voltage and the total harmonic distortion. The double firing method causes zero vectors of output voltage and input current. Designing the mechanism of the converter based on the idea of Park Vector Theory, the number of harmonic distortion in the intervening firing method were compared to those in normal firing method.

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종합 고조파 왜율 일정 제어를 위한 삼상 NPC PWM 인버어터의 제어 기법 (The Control Technique of 3 Phase NPC PWM Inverter to control fixed Total Harmonic Distortion)

  • 송언빈
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1994년도 하계학술대회 논문집 A
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    • pp.565-567
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    • 1994
  • This paper presents a software based NPC PWM inverter control technique to eliminate the harmonics in the output waveforms of inverter. The proposed control technique is able to keep down total harmonic distortion and significantly improve the performance of the inverter. In the control node where the frequency ratio is 36 and the modulation index is $1.2\sim2.0$, the proposed inverter has been operated wi thin 5% Total Harmonic Distortion.

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선택적 주파수 변환방식에 의한 단상 역률보상회로의 캐패시터전압 및 입력전류 고조파왜곡의 감소 (REDUCTION OF VOLTAGE STRESS AND INPUT CURRENT HARMONIC DISTORTION IN SINGLE STAGE PFC CONVERTER BY SELECTIVE VARIABLE FREQUENCY CONTROL)

  • 최항석;이규찬;조보형
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1997년도 하계학술대회 논문집 F
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    • pp.1999-2001
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    • 1997
  • The main two drawbacks of the Sin91e Stage PFC (SS-PFC) converters employing a DCM Boost PFC cell are relatively high voltage stress on the bulk capacitor and the input current harmonic distortion. The high voltage stress on bulk capacitor makes the SS-PFC converter impractical in a universal input application and the input current harmonic distortion lowers power factor. In this paper a selective variable frequency control that reduces the voltage stress on the bulk capacitor and the input current harmonic distortion is proposed. Computer simulation results of the proposed control method are presented.

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연성 효과를 고려한 마이크로스피커 왜율분석 (Analysis of Total Harmonic Distortion in Microspeaker Considering Coupling Effect)

  • 권중학;김광석;방기창;황상문
    • 한국소음진동공학회논문집
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    • 제18권4호
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    • pp.473-479
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    • 2008
  • With the advent of mobile phone, digital multimedia broadcasting(DMB) service is to be realized for multimedia data communication. For an acoustic part, a smaller and lighter microspeaker is also soon to be realized as an MP3 song player and a speakerphone. Sound quality in the microspeaker is becoming more important in mobile phones. It is evaluated by total harmonic distortion(THD). THD is the proportion of higher order frequencies output response to sinusoidal input signal. It is affected by uneven magnetic distribution and nonlinear response of diaphragm. In this paper, harmonic distortion is analyzed by considering magnetic and mechanical coupling effects. Simulated results of THD are compared with experimental data. Results show that THD in lower frequency range is higher due to high displace on voice coil and high mechanical response of high order frequency.

연성 효과를 고려한 마이크로스피커 왜율분석 (Analysis of total harmonic distortion in microspeaker considering coupling effect)

  • 권중학;김광석;방기창;황상문
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2008년도 춘계학술대회논문집
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    • pp.236-241
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    • 2008
  • With the advent of mobile phone, Digital multimedia broadcasting (DMB) service is to be realized for multimedia data communication. For an acoustic part, a smaller and lighter microspeaker is also soon to be realized as an MP3 song player and a speakerphone. Sound quality in the microspeaker is becoming more important in mobile phones. It is evaluated by total harmonic distortion (THD). THD is the proportion of higher order frequencies output response to sinusoidal input signal. It is affected by uneven magnetic distribution and nonlinear response of diaphragm. In this paper, harmonic distortion is analyzed by considering magnetic and mechanical coupling effects. Simulated results of THD are compared with experimental data. Results show that THD in lower frequency range is higher due to high displace on voice coil and high mechanical response of high order frequency.

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