• Title, Summary, Keyword: Harmonic compensation

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A Robust Harmonic Compensation Technique using Digital Lock-in Amplifier under the Non-Sinusoidal Grid Voltage Conditions for the Single Phase Grid Connected Inverters (디지털 록인 앰프를 이용한 비정현 계통 전압 하에서 강인한 단상계통 연계 인 버터용 고조파 보상법)

  • Khan, Reyyan Ahmad;Ashraf, Muhammad Noman;Choi, Woojin
    • Proceedings of the KIPE Conference
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    • pp.95-97
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    • 2018
  • The power quality of Single Phase Grid-Connected Inverters (GCIs) has received much attention with the increasing number of Distributed Generation (DG) systems. However, the performance of single phase GCIs get degraded due to several factors such as the grid voltage harmonics, the dead time effect, and the turn ON/OFF of the switches, which causes the harmonics at the output of GCIs. Therefore, it is not easy to satisfy the harmonic standards such as IEEE 519 and P1547 without the help of harmonic compensator. To meet the harmonic standards a certain kind of harmonic controller needs to be added to the current control loop to effectively mitigate the low order harmonics. In this paper, the harmonic compensation is performed using a novel robust harmonic compensation method based on Digital Lock-in Amplifier (DLA). In the proposed technique, DLAs are used to extract the amplitude and phase information of the harmonics from the output current and compensate it by using a simple PI controller in the feedforward manner. In order to show the superior performance of the proposed harmonic compensation technique, it is compared with those of conventional harmonic compensation methods in terms of the effectiveness of harmonic elimination, complexity, and implementation. The validity of the proposed harmonic compensation techniques for the single phase GCIs is verified through the experimental results with a 5kW single phase GCI. Index Terms -Single Phase Grid Connected Inverter (SPGCI), Harmonic Compensation Method, Total Harmonic Distortion (THD) and Harmonic Standard.

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AC harmonic elimination and reactive power compensation by voltage-type active filter (전압형 능동필터에 의한 교류고조파제거와 무효전력보상)

  • 김한성;최규하;신우석;이제필
    • 제어로봇시스템학회:학술대회논문집
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    • pp.688-692
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    • 1988
  • The active filter system for harmonic current compensation is presented in this paper. The active filter, composed of a three-phase voltage-type PWM inverter and the capacitor, compensates both the harmonic currents and the reactive power by injecting the PWM current to the ac line. This paper describes the principle of harmonic current compensation, the calculation circuits for the harmonic currents to be injected, the several compensation characteristics. Also the experimental results are shown to verify the theory proposed in this paper.

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Intelligent Coordination Method of Multiple Distributed Resources for Harmonic Current Compensation in a Microgrid

  • Kang, Hyun-Koo;Yoo, Choel-Hee;Chung, Il-Yop;Won, Dong-Jun;Moon, Seung-Il
    • Journal of Electrical Engineering and Technology
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    • v.7 no.6
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    • pp.834-844
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    • 2012
  • Nonlinear electronic loads draw harmonic currents from the power grids that can cause energy loss, miss-operation of power equipment, and other serious problems in the power grids. This paper proposes a harmonic compensation method using multiple distributed resources (DRs) such as small distributed generators (DGs) and battery energy storage systems (BESSs) that are integrated to the power grids through power inverters. For harmonic compensation, DRs should inject additional apparent power to the grids so that certain DRs, especially operated in proximity to their rated power, may possibly reach their maximum current limits. Therefore, intelligent coordination methods of multiple DRs are required for efficient harmonic current compensation considering the power margins of DRs, energy cost, and the battery state-of-charge. The proposed method is based on fuzzy multi-objective optimization so that DRs can cooperate with other DRs to eliminate harmonic currents with optimizing mutually conflicting multi-objectives.

Harmonic Current Compensation Method Using Inverter-Interfaced Distributed Generators (인버터 연계형 분산전원을 이용한 배전계통 고조파 전류 보상원리)

  • Chung, Il-Yop;Kang, Hyun-Koo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.2
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    • pp.279-284
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    • 2011
  • Harmonic distortions in current waveform may cause significant problems in electric power system facility and operation. This paper presents an adaptive parameter estimation method to detect harmonic current components caused by nonlinear loads. In addition, a coordination strategy for multiple inverter-interfaced distributed generators to compensate the harmonic currents is discussed. The coordination strategy is realized by distributing the harmonic compensation participation index to individual distributed generators. The harmonic compensation participation index can be determined by the amount of remaining power generation capacity of each distributed generator. Simulation results based on switching-level inverter models show that the proposed harmonic detection method has good performance and the coordination strategy can improve harmonic problems efficiently.

Control Strategy and Characteristic Analysis of Hybrid Active Power Filters with the Resonant Impedance Principle

  • Fang, Lu;Xu, Xian-Yong;Luo, An;Li, Yan;Tu, Chun-Ming;Fang, Hou-Hui
    • Journal of Power Electronics
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    • v.12 no.6
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    • pp.935-946
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    • 2012
  • A new kind of resonant impedance type hybrid active filter (RITHAF) is proposed for dynamic harmonic current suppression and high capacity reactive compensation in medium and high voltage systems. This paper analyzed the different performance of the RITHAF when the active part of the RITHAF is controlled as a current source and as a voltage source, respectively. The harmonic suppression function is defined in this paper. The influences of the changes caused by the grid impedance and the detuning of the passive power filter on the compensating characteristics of the RITHAF are studied by analyzing the suppression function. Simulation and industrial application results show that the RITHAF has excellent performances in harmonic suppression and reactive compensation, which is suitable for medium and high voltage systems.

A Novel Multi-Function PV Micro-Inverter with an Optimized Harmonic Compensation Strategy

  • Zhu, Guofeng;Mu, Longhua;Yan, Junhua
    • Journal of Power Electronics
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    • v.16 no.6
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    • pp.2284-2293
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    • 2016
  • With the rapid development of clean energy, photovoltaic (PV) generation has been utilized in the harmonic compensation of power systems. This paper presents a novel multi-function PV micro-inverter with three stages (pseudo-two-stage). It can inject active power and compensate harmonic currents in the power grid at the same time. In order to keep the micro-inverter working under the maximum allowable output power, an optimized capacity limitation strategy is presented. Moreover, the harmonic compensation can be adjusted according to the customized requirements of power quality. Additionally, a phase shedding strategy in the DC/DC stage is introduced to improve the efficiency of parallel Boost converters in a wide range. Compared with existing capacity limitation methods, the proposed strategy shows better performance and energy efficiency. Simulations and experiments verify the feasibility of the micro-inverter and the effectiveness of the strategy.

Torque Ripple Reduction Algorithm of PM Synchronous Motor at High Speed Operation (영구자석 동기 전동기의 고속운전 시 토크리플 저감 알고리즘)

  • Kim, Jong-Hyun;Cho, Kwan-Yuhl;Kim, Hag-Wone
    • The Transactions of the Korean Institute of Power Electronics
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    • v.20 no.5
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    • pp.429-436
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    • 2015
  • Torque ripples generate mechanical vibration at low speed and acoustic noise at high speed. The back emf harmonics of a PM synchronous motor is one of the main sources of torque ripples. To reduce torque ripples resulting from back emf harmonics, dq-axis harmonic currents that reduce the torque ripples are generally compensated to the current controller. Harmonic current compensation is effective at low speed, but it is not applicable at high speed because of the limited bandwidth of the current controller. In this study, dq-axis harmonic voltage compensation that can reduce torque ripples at high speed is proposed. The dq-axis harmonic voltages are calculated from the motor speed and the dq-axis harmonic currents. The effectiveness of the proposed method in reducing torque ripple is verified by a simulation and experiments.

A 2nd Order Harmonic Compensation Method for Wind Power System Using a PR Controller

  • Jeong, Hae-Gwang;Lee, Jong-Hyun;Lee, Kyo-Beum
    • Journal of Electrical Engineering and Technology
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    • v.8 no.3
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    • pp.507-515
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    • 2013
  • This paper proposes a compensation method for the $2^{nd}$-order harmonic of single-phase grid-connected wind power generation systems. Theoretically, a single-phase grid-connected inverter system has no choice but to cause the $2^{nd}$-order harmonic to DC-link voltage. The reference active current is affected by the DC-link voltage. The output current from the reference active current is distorted by the $1^{st}$ and $3^{rd}$-order harmonic. The proposed method can compensate, conveniently, the reference active current with the $2^{nd}$-order harmonic. To reduce the $2^{nd}$-order ripple in the reference active current, proposed method takes a PR controller as a feed-forward compensator. PR controllers can implement selective harmonic compensation without excessive computational requirements; the use of these controllers simplifies the method. Both the simulation and experimental results agree well with the theoretical analysis.

New series Active power filtering system to reduce the harmonic in 3-Phase 3-Wire system (3상 3선식 전력계통의 고조파 저감을 위한 새로운 직렬형 능동 필터 시스템)

  • 한윤석
    • Proceedings of the KIPE Conference
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    • pp.119-122
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    • 2000
  • This paper presents a new compensation method of series active power filter. The proposed method applied in the three-phase three-wire system can generate harmonic compensation voltage in front of the harmonic source. Futhermore it is also expended to three-phase four-wire system considering zero-sequence voltage. The compensation principle is described in detail. Experimental result show the validity of the proposed method in the three-phase three-wire system

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A Study on the Series Active Power Filter for Harmonic Reduction and Unbalanced Source Voltage Compensation (전류 고조파와 불평형 전원 전압 보상을 위한 직렬형 능동전력필터에 관한 연구)

  • Oh, Jae-Hoon;Han, Yoon-Seok;Kim, Young-Seok;Won, Chung-Yuen;Choi, Se-Wan
    • Proceedings of the KIEE Conference
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    • pp.191-194
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    • 2001
  • In this paper, we propose a series active power filter control method to compensate current harmonics and unbalanced source voltage. The system is composed of series active power filter and shunt passive filer that are tuned 5th and 7th harmonics. In this conventional system, series active power filter complements drawbacks of the shunt passive filter, namely improves harmonic compensation characteristics, and compensates unbalanced source voltage. In the proposed algorithm, compensation voltage for harmonic reduction is calculated by performance function, and compensation voltage for unbalanced source voltage is calculated in based on a synchronous reference frame. So, ultimate compensation voltage is sum of those two compensation voltages. By computer simulation, we verify the excellency of proposed method.

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