• Title/Summary/Keyword: Harmonics and reactive power

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A novel control strategy of active power filter type bidirectional UPS (능동필터형 쌍방향 UPS의 새로운 제어기법)

  • Kim, Je-Hong;Yeom, Sang-Ku;Choi, Jae-Ho
    • Proceedings of the KIEE Conference
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    • 1997.07f
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    • pp.2082-2084
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    • 1997
  • This paper proposes a new control strategy of bidirectional uninterruptible power supply(UPS) with the performance of active power filter which compensate the harmonics and reactive power. To improve the transient response for the effective compensation in active power filter mode, it is considered that a simple and precise calculation method of the compensation reference current for the harmonics and reactive power compensation. So a novel closed-loop control strategy is used to calculate the reference current. And the current regulated instantaneous voltage control scheme is used in back-up power mode. The system model and control algorithm are described and analyzed, and the system Performance is verified by the simulation and experimental results.

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Multifunctional Uninterruptible Power Supply (UPS) System

  • Kim, Je-Hong;Choi, Yong-Joon;Choi, Jae-Ho
    • Proceedings of the KIPE Conference
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    • 1998.10a
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    • pp.813-817
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    • 1998
  • This paper proposes a new control strategy of bidirectional uninterruptible power supply(UPS) with the performance of active power filter which compensate the harmonics and reactive power. To improve the transient response for the effective compensation in active power filter mode. It is considered that a simple and precise calculation method of the compensation reference current for the harmonics and reactive power compensation. So a novel closed-loop control strategy is used to calculate the reference current. The system model and control algorithm are described and the system performance is verified by the simulation and experimental results.

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A Simplified Control Algorithm for Three-Phase, Four-Wire Unified Power Quality Conditioner

  • Singh, Bhim;Venkateswarlu, P.
    • Journal of Power Electronics
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    • v.10 no.1
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    • pp.91-96
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    • 2010
  • In this paper, a simplified control algorithm for a three-phase, four-wire unified power quality conditioner (UPQC) is presented to compensate for supply voltage distortions/unbalance, supply current harmonics, the supply neutral current, the reactive power and the load unbalance as well as to maintain zero voltage regulation (ZVR) at the point of common coupling (PCC). The UPQC is realized by the integration of series and shunt active filters (AFs) sharing a common dc bus capacitor. The shunt AF is realized using a three-phase, four leg voltage source inverter (VSI) and the series AF is realized using a three-phase, three leg VSI. A dynamic model of the UPQC is developed in the MATLAB/SIMULINK environment and the simulation results demonstrating the power quality improvement in the system are presented for different supply and load conditions.

Multifunctional UPS with Mode Transfer Method (모드절환식 다기능 무정전 전원장치)

  • Kim, Je-Hong
    • Proceedings of the KIEE Conference
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    • 2001.07b
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    • pp.1049-1051
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    • 2001
  • This paper proposes a new control strategy of multifunctional uninterruptible power supply(UPS) with the performance of active power filter which compensate the harmonics and reactive power. To improve the transient response for the effective compensation in active power filter mode, it is considered that a simple and precise calculation method of the compensation reference current for the harmonics and reactive power compensation. So a novel closed-loop control strategy is used to calculate the reference current. And the current regulated instantaneous voltage control scheme is used in back-up power mode. The system model and control algorithm are described and analyzed, and the system performance is verified by the simulation results.

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The Harmonics and Reactive Power Compensation with Series Active Power filter in 3-phase 4-wire System (3상 4선식 전력시스템에서 직렬형 능동필터에 의한 고조파전류와 무효전력 보상에 관한 연구)

  • Kim, Jin-Sun;Kim, Young-Jo;Kim, Young-Seok
    • Proceedings of the KIEE Conference
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    • 2003.07b
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    • pp.1072-1074
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    • 2003
  • In this paper, a new control strategy of a series active power filter using direct compensating voltage extraction method is proposed. This control algorithm compensates harmonics, reactive power and neutral line currents which are generated by balanced or unbalanced nonlinear loads. The advantage of this method is that the compensating voltage of the series active power filter can be extracted without phase transformation. Therefore, calculation time is shorten and the control method is simple compared with conventional method as the p-q theory In addition, this control strategy was applied for the series active power filter in 3-phase 4-wire system which is widely employed in distributing electric energy to several office building and manufacturing plants. Some results obtained from the experimental model using the proposed method are presented to demonstrate and confirm its validity.

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The Expanded Current Synchronous Detection for Active Power Filters (능동전력필터를 위한 확장된 전류 동기 검출법)

  • 정영국;김우용;임영철
    • The Transactions of the Korean Institute of Power Electronics
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    • v.6 no.4
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    • pp.341-347
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    • 2001
  • Harmonics and fundamental reactive current of nonlinear loads in serious unbalanced power condition, are compensated by current synchronous detection(CSD) theory which is also acceptable for single phase power system. But, the CSD theory is not suitable any more, in case of controlled independently harmonics and reactive component. Therefore, a new algorithm, the expanded current synchronous detection(ECSD) theory for a three phase active power filter based on decomposition of fundamental reactive, distorted components, is proposed in this paper. The proposed ECSD theory is experimented and tested comparison with a few power theories under asymmetrical condition in power system.

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The Anti-Islanding Method with Compensation of Load Reactive Power for Grid-connected Photovoltaic Generation System (계통 연계형 태양광 발전 시스템의 부하 무효전력 보상이 적용된 단독운전 인지법)

  • Jeong, Jin-Beom;Shin, Dong-Hyun;Kim, Hee-Jun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.1
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    • pp.58-64
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    • 2008
  • In this paper, we present an active anti-islanding method with a load monitoring system using reactive power control. The proposed method, which is based on reactive power control, has fewer harmonics components than those in conventional methods, and it can minimize the reactive power component of the grid because it compensates the reactive power component with the load monitoring. The proposed quick islanding detection method was confirmed from the experimental results with an inverter for a 3kW photovoltaic system.

PI and Fuzzy Logic Controller Based 3-Phase 4-Wire Shunt Active Filters for the Mitigation of Current Harmonics with the Id-Iq Control Strategy

  • Mikkili, Suresh;Panda, Anup Kumar
    • Journal of Power Electronics
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    • v.11 no.6
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    • pp.914-921
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    • 2011
  • Commencing with incandescent light bulbs, every load today creates harmonics. Unfortunately, these loads vary with respect to their amount of harmonic content and their response to problems caused by harmonics. The prevalent difficulties with harmonics are voltage and current waveform distortions. In addition, Electronic equipment like computers, battery chargers, electronic ballasts, variable frequency drives, and switching mode power supplies generate perilous amounts of harmonics. Issues related to harmonics are of a greater concern to engineers and building designers because they do more than just distort voltage waveforms, they can overheat the building wiring, cause nuisance tripping, overheat transformer units, and cause random end-user equipment failures. Thus power quality is becoming more and more serious with each passing day. As a result, active power filters (APFs) have gained a lot of attention due to their excellent harmonic compensation. However, the performance of the active filters seems to have contradictions with different control techniques. The main objective of this paper is to analyze shunt active filters with fuzzy and pi controllers. To carry out this analysis, active and reactive current methods ($i_d-i_q$) are considered. Extensive simulations were carried out. The simulations were performed under balance, unbalanced and non sinusoidal conditions. The results validate the dynamic behavior of fuzzy logic controllers over PI controllers.

Simplified Control Scheme of Unified Power Quality Conditioner based on Three-phase Three-level (NPC) inverter to Mitigate Current Source Harmonics and Compensate All Voltage Disturbances

  • Salim, Chennai;Toufik, Benchouia Mohamed
    • Journal of Electrical Engineering and Technology
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    • v.8 no.3
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    • pp.544-558
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    • 2013
  • This paper proposes a simplified and efficient control scheme for Unified Power Quality Conditioner (UPQC) based on three-level (NPC) inverter capable to mitigate source current harmonics and compensate all voltage disturbances perturbations such us, voltage sags, swells, unbalances and harmonics. The UPQC is designed by the integration of series and shunt active filters (AFs) sharing a common dc bus capacitor. The dc voltage is maintained constant using proportional integral voltage controller. The shunt and series AF are designed using a three-phase three-level (NPC) inverter. The synchronous reference frame (SRF) theory is used to get the reference signals for shunt and the power reactive theory (PQ) for a series APFs. The reference signals for the shunt and series APF are derived from the control algorithm and sensed signals are injected in tow controllers to generate switching signals for series and shunt APFs. The performance of proposed UPQC system is evaluated in terms of power factor correction and mitigation of voltage, current harmonics and all voltage disturbances compensation in three-phase, three-wire power system using MATLAB-Simulink software and SimPowerSystem Toolbox. The simulation results demonstrate that the proposed UPQC system can improve the power quality at the common connection point of the non-linear load.

High Power Factor Control of High-speed Single-phase BLDC Motor (초고속 단상 BLDC 전동기의 고역률 전력 제어 방법)

  • Lee, Wook-Jin;Jung, Bumun
    • The Transactions of the Korean Institute of Power Electronics
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    • v.21 no.2
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    • pp.144-149
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    • 2016
  • This paper presents a power control method of high-speed single-phase BLDC motor. Most electric appliances require a power factor corrector (PFC) to mitigate grid current harmonics. However, the reactive components and power semiconductors in the PFC increase system cost and dimension. In this paper, a new motor drive system for a high-speed single-phase BLDC motor is proposed, which can decrease grid current harmonics without PFC by directly manipulating motor power and eliminating bulky electrolytic dc-link capacitor. Given that the proposed motor power control method does not require motor current controller, no current sensor is necessary. Moreover, the proposed algorithms can be easily implemented using a low-cost micro-controller. The effectiveness of the proposed power control method is verified by experiments.