• Title/Summary/Keyword: harmonic current compensation

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Unified Active Power Filter Compensating For Source Voltage Unbalance/Current Harmonics and Power Factor Simultaneously (전원 전압의 불평형과 고조파 전류 및 역률을 동시에 보상하는 통합형 능동 전력필터)

  • Lee, Jong-Kun;Seok, Jul-Ki;Lee, Dong-Choon
    • Proceedings of the KIEE Conference
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    • 2004.04a
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    • pp.103-105
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    • 2004
  • In this paper, a novel control scheme compensating for source voltage unbalance and current harmonics and power factor simultaneously in unified active power filter systems combined with shunt passive filters is proposed, where no low/high-pass filter are used in deriving the reference voltage for compensation. Using digital all-pass filters, the phase angle and the reference voltages compensating for harmonic current and unbalanced voltage are derived from the positive sequence component of the unbalanced voltage. The amplitude of d-axis current in a series filter is controlled as zero for power factor correction. The validity of the proposed control scheme has been verified by experimental results.

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

  • Yang, Songhee;Park, Jin-Hyuk;Lee, Kyo-Beum
    • The Transactions of the Korean Institute of Power Electronics
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    • v.22 no.2
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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.

An Active Power Filter For A Compensation Of Power Factor and Harmonic Currents (역률개선 및 고조파 보상을 위한 능동전력필터)

  • Kim, Yong-Ho;Ahn, Bok-Shin
    • Proceedings of the KIEE Conference
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    • 1991.07a
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    • pp.447-450
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    • 1991
  • A novel effective calculation method of the compensation current commands of active power filter using voltage source PWM converter is proposed on the basis of the instantaneous reactive power theory. The load currents and the phase of the source voltages are used for the simplification of the calculations and the reduction of the its time. And the calculation of the currents is performed by DSP 32014 within 50 uSEC. For reducing the DC voltage and saving the costs, a passive power filters are used. The simulation results of the effects of the active power filter with a passive filter are presented.

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Modular Multilevel Converter Based STATCOM Topology Suitable for Medium-Voltage Unbalanced Systems

  • Pirouz, Hassan Mohammadi;Bina, Mohammad Tavakoli
    • Journal of Power Electronics
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    • v.10 no.5
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    • pp.572-578
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    • 2010
  • This paper discusses a transformerless shunt static compensator (STATCOM) based on a modular multilevel converter (MMC). It introduces a new time-discrete appropriate current control algorithm and a phase-shifted carrier modulation strategy for fast compensation of the reactive power and harmonics, and also for the balancing of the three-phase source side currents. Analytical formulas are derived to demonstrate the accurate mechanism of the stored energy balancing inside the MMC. Various simulated waveforms verify that the MMC based STATCOM is capable of reactive power compensation, harmonic cancellation, and simultaneous load balancing, while controlling and balancing all of the DC mean voltages even during the transient states.

Stand-Alone Type Single-Phase Fuel Cells Micro-Source with ac Voltage Compensation Capability (교류전압 보상 기능을 갖는 독립형 단상 연료전지 마이크로 소스)

  • Jung, Young-Gook
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.1
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    • pp.35-41
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    • 2009
  • This paper proposes a stand alone type single-phase fuel cells micro-source with a voltage sag compensator for compensating the ac output voltage variations (sag or swell) of micro-source. The proposed micro-source is consist of a PEM(polymer electrolyte membrane) fuel cells simulator, a full bridge de converter, a 60Hz PWM(pulse width modulation) VSI(voltage source inverter), and a voltage sag compensator. Voltage sag compensator is similar to the configuration of hybrid series active power filter, and it is directly connected to micro-source through the injection transformer. Compensation algorithm of a voltage sag compensator adopts a single phase p-q theory. Effectiveness of the proposed the system is verified by the PSIM(power electronics simulation tool) simulation in the steady state and transient state which the proposed system is able to simultaneously compensate the harmonic current and source voltage sag or swell.

Digital Control of Single Phase UPS for Input Power Factor Compensation (입력역률 보정을 위한 단상 UPS의 디지털제어)

  • Kim, D.G.;Lee, S.H.;Park, H.A.;Lee, K.Y.;Han, E.Y.;Baek, H.L.
    • Proceedings of the KIEE Conference
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    • 1998.07f
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    • pp.2054-2056
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    • 1998
  • A conventional UPS can supply the clean power to the load. However, it may generate input current harmonics and the input power factor can be very poor. Therefore, the UPS itself may be a power interruption. This paper provides multifunctional converter of using single phase UPS. The proposed UPS can supply the clean power to the load without polluting the mains power system. The multi-functional converter provides battery charging, var compensation and harmonic suppression simultaneously. It was simulated to verify this work.

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Performance Improvement of Model Predictive Control Using Control Error Compensation for Power Electronic Converters Based on the Lyapunov Function

  • Du, Guiping;Liu, Zhifei;Du, Fada;Li, Jiajian
    • Journal of Power Electronics
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    • v.17 no.4
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    • pp.983-990
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    • 2017
  • This paper proposes a model predictive control based on the discrete Lyapunov function to improve the performance of power electronic converters. The proposed control technique, based on the finite control set model predictive control (FCS-MPC), defines a cost function for the control law which is determined under the Lyapunov stability theorem with a control error compensation. The steady state and dynamic performance of the proposed control strategy has been tested under a single phase AC/DC voltage source rectifier (S-VSR). Experimental results demonstrate that the proposed control strategy not only offers global stability and good robustness but also leads to a high quality sinusoidal current with a reasonably low total harmonic distortion (THD) and a fast dynamic response under linear loads.

An Enhanced Instantaneous Circulating Current Control for Reactive Power and Harmonic Load Sharing in Islanded Microgrids

  • Lorzadeh, Iman;Abyaneh, Hossein Askarian;Savaghebi, Mehdi;Lorzadeh, Omid;Bakhshai, Alireza;Guerrero, Josep M.
    • Journal of Power Electronics
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    • v.17 no.6
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    • pp.1658-1671
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    • 2017
  • To address the inaccurate load demand sharing problems among parallel inverter-interfaced voltage-controlled distributed generation (DG) units in islanded microgrids (MGs) with different DG power ratings and mismatched feeder impedances, an enhanced voltage control scheme based on the active compensation of circulating voltage drops is proposed in this paper. Using the proposed strategy, reactive power and harmonic currents are shared accurately and proportionally without knowledge of the feeder impedances. Since the proposed local controller consists of two well-separated fundamental and harmonic voltage control branches, the reactive power and harmonic currents can be independently shared without having a remarkable effect on the amplitude or quality of the DGs voltage, even if nonlinear (harmonic) loads are directly connected at the output terminals of the units. In addition, accurate load sharing can also be attained when the plug-and-play performance of DGs and various loading conditions are applied to MGs. The effects of communication failures and latency on the performance of the proposed strategy are also explored. The design process of the proposed control system is presented in detail and comprehensive simulation studies on a three-phase MG are provided to validate the effectiveness of the proposed control method.

A study on proportional multiple-resonance controller for harmonic distortion compensation of single phase VSIs (단상 전압 소스 인버터의 고조파 왜곡 보상을 위한 비례 다중 공진 제어기에 관한 연구)

  • Bongwoo Kwak
    • Journal of IKEEE
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    • v.27 no.3
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    • pp.319-326
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    • 2023
  • In this paper, simulation and experimental results are presented, including the implementation of a digital controller for robust output voltage control of a single-phase voltage source inverters (VSIs) and total harmonic distortion (T.H.D.v) analysis. Typically, the VSIs uses a proportional integral (PI) controller for the current controller on the inner loop and a proportional resonant (PR) controller for the voltage controller on the outer loop to control the output voltage. However, non-linear loads still produce high-order odd harmonic distortion. Therefore, in this paper, a proportional multiple resonance (PMR) controller with a resonance controller for odd harmonic frequencies is proposed to suppress harmonic distortion. Analyze the frequency response of controllers for VSI plants and design PMR controllers. Through simulation, the total harmonic distortion characteristics of the output voltage are compared and verified when PI and PMR are used as voltage controllers. Both linear and non-linear loading conditions were considered. Finally, the effectiveness of the PMR controller was demonstrated by applying it to a 3kW VSIs prototype.

A Solid State Controller for Self-Excited Induction Generator for Voltage Regulation, Harmonic Compensation and Load Balancing

  • Singh Bhim;Murthy S. S.;Gupta Sushma
    • Journal of Power Electronics
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    • v.5 no.2
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    • pp.109-119
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    • 2005
  • This paper deals with the performance analysis of static compensator (STATCOM) based voltage regulator for self­excited induction generators (SEIGs) supplying balanced/unbalanced and linear/ non-linear loads. In practice, most of the loads are linear. But the presence of non-linear loads in some applications injects harmonics into the generating system. Because an SEIG is a weak isolated system, these harmonics have a great effect on its performance. Additionally, SEIG's offer poor voltage regulation and require an adjustable reactive power source to maintain a constant terminal voltage under a varying load. A three-phase insulated gate bipolar transistor (IGBT) based current controlled voltage source inverter (CC- VSI) known as STATCOM is used for harmonic elimination. It also provides the required reactive power an SEIG needs to maintain a constant terminal voltage under varying loads. A dynamic model of an SEIG-STATCOM system with the ability to simulate varying loads has been developed using a stationary d-q axes reference frame. This enables us to predict the behavior of the system under transient conditions. The simulated results show that by using a STATCOM based voltage regulator the SEIG terminal voltage can be maintained constant and free from harmonics under linear/non linear and balanced/unbalanced loads.