• 제목/요약/키워드: Current distortion

검색결과 804건 처리시간 0.028초

3상 양방향 인버터의 계통전압 불평형 및 왜곡에 의한 계통전류 보상 (The Compensation of the Grid Current Distortion caused by the Grid Voltage Unbalance and Distortion for 3-Phase Bi-Directional DC to AC Inverter)

  • 양승대;김승민;최주엽;최익;송승호;이상철;이동하
    • 한국태양에너지학회 논문집
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    • 제32권spc3호
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    • pp.228-234
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    • 2012
  • This paper presents the algorithm of the compensation of the grid current distortion caused by the grid voltage unbalance and distortion in 3-phase bi-directional DC to AC inverter. Usually 3-phase grid system has unbalance and distortion because of connecting 1-phase and non-linear load with 3-phase load using same input node. Controlling 3-phase inverter by general method under the unbalanced and distorted grid voltage, the grid current has distortion. This distortion of the grid current cause the grid voltage distortion again. So, it need to control the grid current balanced and non-distorted, even the grid voltage gets unbalanced and distorted. There are some complex method to compensate the gird current distortion. it sugest simple method to solve the problem. PSIM simulation is used to validate the proposed algorithm.

듀얼벅 인버터의 무효전력 보상 시 전류 왜곡 저감 (Alleviate Current Distortion of Dual-buck Inverter During Reactive Power Support)

  • 한상훈;조영훈
    • 전력전자학회논문지
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    • 제27권2호
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    • pp.134-141
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    • 2022
  • This study presents a method for reducing current distortion that occurs when a dual-buck inverter generates reactive power. Dual-buck inverters, which are only capable of unity power factor operation, can generate reactive power capabilities by modifying a modulation technique. However, under non-unity power factor conditions, current distortion occurs at zero-crossing points of grid voltage and output current. This distortion is caused by parasitic capacitors, dead-time, and discontinuous conduction mode operation. This study proposes a modified modulation method to alleviate the current distortion at zero-crossing point of the grid voltage. A repetitive controller is applied to reduce this distortion of the output current. A 1 kVA prototype is built and tested. Simulation and experimental results demonstrate the effectiveness of the proposed method.

Suppression of Leakage Current and Distortion in Variable Capacitance Devices and their Application to AC Power Regulators

  • Katsuki, Akihiko;Oki, Takuya
    • Journal of Power Electronics
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    • 제16권1호
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    • pp.66-73
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    • 2016
  • The quantity of alternating current (AC) leakage and the value of distortion factor in capacitor currents are discussed with regard to a new power component called variable capacitance device (VCD). This component has terminals for controlling its capacitance. Nonlinear dielectric characteristics are utilized in this device to vary the capacitance. When VCD operates in an AC circuit, the AC leakage from this device through direct current (DC) control voltage source increases according to the conditions of DC control voltage and so on. To solve this problem, we propose techniques for suppressing AC leakage. Although VCD has strong nonlinear characteristics, the current through the capacitor is not distorted significantly. The relations between AC leakage and the distortion in current waveforms are investigated. An application example for an AC power regulator is also introduced to evaluate the distortion in waveforms.

Scheme to Improve the Line Current Distortion of PFC Using a Predictive Control Algorithm

  • Kim, Dae Joong;Park, Jin-Hyuk;Lee, Kyo-Beum
    • Journal of Power Electronics
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    • 제15권5호
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    • pp.1168-1177
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    • 2015
  • This paper presents a scheme to improve the line current distortion of power factor corrector (PFC) topology at the zero crossing point using a predictive control algorithm in both the continuous conduction mode (CCM) and discontinuous conduction mode (DCM). The line current in single-phase PFC topology is distorted at the zero crossing point of the input AC voltage because of the characteristic of the general proportional integral (PI) current controller. This distortion degrades the line current quality, such as the total harmonic distortion (THD) and the power factor (PF). Given the optimal duty cycle calculated by estimating the next state current in both the CCM and DCM, the proposed predictive control algorithm has a fast dynamic response and accuracy unlike the conventional PI current control method. These advantages of the proposed algorithm lower the line current distortion of PFC topology. The proposed method is verified through PSIM simulations and experimental results with 1.5 kW bridgeless PFC (BLPFC) topology.

3상 양방향 인버터의 계통전압 불평형 및 왜곡에 의한 계통전류 불평형 및 왜곡 보상 (A Compensation of the Grid Current Unbalance and Distortion caused by the Grid Voltage Unbalance and Distortion in 3-Phase Bi-Directional DC to AC Inverter)

  • 양승대;김승민;최주엽;최익;송승호;이상철;이동하
    • 전력전자학회논문지
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    • 제18권2호
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    • pp.161-168
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    • 2013
  • This paper presents an algorithm of a compensation of the grid current distortion caused by the grid voltage unbalance and distortion in 3-phase bi-directional DC to AC inverter. Usually 3-phase grid system has unbalance and distortion because of connecting 1-phase and non-linear load with 3-phase load using same input node. Controlling 3-phase inverter by general method under the unbalanced and distorted grid voltage, the grid current has distortion. This distortion of the grid current cause the grid voltage distortion again. So, it need to control the grid current balanced and non-distorted, even the grid voltage gets unbalanced and distorted. There are some complex method to compensate the gird current distortion. it suggest simple method to solve the problem. Simulation and experiment is used to validate the proposed algorithm.

DH Laser Diode의 Threshold Current에 대한 2차 고조파 왜곡의 이론적 해석 (Theoretical Analysis of Second Harmonic Distortion for Threshold Current in DH Laser Diode)

  • 김성일;박한규
    • 대한전자공학회논문지
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    • 제17권2호
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    • pp.10-14
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    • 1980
  • 본 논문에서는 DH-laser diode의 threshold current를 계산하기 위하여 2차고조파 왜곡 (se cond harmonic distortion)에 대해 Rate 방정식 (Rate-equation)을 동적상태와 정적상태 방정식으로 연릴하여 계산하였다. 특히 고조파 왜곡 ( )을 계산하는데 바이어스 전류 에 대하여 변조 전류 을 변조계수 m으로 놓고 (Jm=mJo)계산하여 주입전류 J가 Jth에서 2차 고조파 왜곡이 최대치를 가짐을 보여 ,이제까지 알려진 Jth조사 방법보다 간편하고 정확하게 조사할 수 있음을 제시하였다.

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높은 스위칭 주파수를 가지는 비엔나 정류기의 전류 품질 개선 (Letters Current Quality Improvement for a Vienna Rectifier with High-Switching Frequency)

  • 양송희;박진혁;이교범
    • 전력전자학회논문지
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    • 제22권2호
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    • pp.181-184
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    • 2017
  • This study analyzes the turn-on and turn-off transients of a metal-oxide-semiconductor field-effect transistor (MOSFET) with high-switching frequency systems. In these systems, the voltage distortion becomes serious at the output terminal of a Vienna rectifier by the turn-off delay of the MOSFET. The current has low-order harmonics through this voltage distortion. This paper describes the transient of the turn-off that causes the voltage distortion. The algorithm for reducing the sixth harmonic using a proportional-resonance controller is proposed to improve the current distortion without complex calculation for compensation. The reduction of the current distortion by high-switching frequency is verified by experiment with the 2.5-kW prototype Vienna rectifier.

전류 스위칭 시스템의 CFT 오차 감소에 관한 연구 (A study on the CFT error reduction of switched-current system)

  • 최경진;이해길;신홍규
    • 한국통신학회논문지
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    • 제21권5호
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    • pp.1325-1331
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    • 1996
  • 본 논문에서는 전류 스위칭(switched-current:SI) 시스템에서 THD(total harmonic distortion) 증가 원인인 클럭피드스루(clock feedthrough:CFT) 오차 전압을 감소시키는 새로운 전류 메모리(current-memory) 회로를 제안하였다. 제안한 전류 메모리는 CMOS 상보형의 PMOS 트랜지스터를 이용하여 CFT 오차 전압에 의한 출력 왜곡 전류를 감소시킨다. 제안한 전류 메모리 회로를 $1.2{\mu}{\textrm{m}}$ CMOS 공정을 사용하여 설계하고, 입력으로 전류 크기 $68{\mu}{\textrm{m}}$인 1MHz 정현파 신호를 인가하였다.(샘플링 주파수:20MHz) 모의 실험 결과, 기존의 전류 메모리보다 CFT 오차 전압에 의한 출력 왜곡 전류가 10배 정도 감소를 나타내었으며 신호 대 바이어스 전류비가 0.5(peak signal-to-bias current ratio:i/J)인 1KHz 신호를 인가할 경우 THD는 -57dB이다.

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EPDM 고분자 애자에 대한 표면방전 및 누설전류파형의 고조파분석 (Harmonics Analysis of Leakage Current Waveforms and Surface Discharge for EPDM Polymer Insulator)

  • 박재준;양태규
    • 한국전기전자재료학회논문지
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    • 제17권9호
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    • pp.1013-1021
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    • 2004
  • This paper presents the results of spectrum analysis of leakage current waveforms on contaminated polymer insulators under fog conditions. This is a basic study on development of a monitoring for aging degree and surface pollution state using distortion rate(%) of 3rd and 5th harmonics according fundamental frequency[60Hz] under environment conditions. Arcing on the surface was always associated with distortion in the leakage current ; hence the low frequency components of the leakage current can be used as a means to evaluate the surface degradation. The results indicate that the distortion rate by spectrum analysis is available for the monitoring of contamination condition of EPDM Polymer insulators.

Reducing Current Distortion in Indirect Matrix Converters Operating in Boost Mode under Unbalanced Input Conditions

  • Choi, Dongho;Bak, Yeongsu;Lee, Kyo-Beum
    • Journal of Power Electronics
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    • 제19권5호
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    • pp.1142-1152
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    • 2019
  • This paper presents a control method for reducing the current distortion in an indirect matrix converter (IMC) operating in boost mode under unbalanced input conditions. IMCs operating in boost mode are useful in distributed generation (DG) systems. They are connected with renewable energy systems (RESs) and the grid to transmit the power generated by the RES. However, under unbalanced voltage conditions of the RES, which is connected with the input stage of the IMC operating in boost mode, the input-output currents are distorted. In particular, the output current distortions cause a ripple of the power, which is transferred to the grid. This aggravates the reliability and stability of the DG system. Therefore, in this paper, a control method using positive/negative sequence voltages and currents is proposed for reducing the current distortion of both side in IMCs operating in boost mode. Simulation and experimental results have been presented to validate effectiveness of the proposed control method.