• Journal of Power Electronics
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• v.14 no.6
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• pp.1303-1313
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• 2014

Dynamic behavior of the harmonic detection part of an active power filter (APF) has an essential role in filter compensation performances during transient conditions. Instantaneous power (p-q) theory is extensively used to design harmonic detectors for active filters. Large overshoot of p-q theory method deteriorates filter response at a large and rapid load change. In this study the harmonic estimation of an APF during transient conditions for balanced three-phase nonlinear loads is conducted. A novel fuzzy instantaneous power (FIP) theory is proposed to improve conventional p-q theory dynamic performances during transient conditions to adapt automatically to any random and rapid nonlinear load change. Adding fuzzy rules in p-q theory improves the decomposition of the alternating current components of active and reactive power signals and develops correct reference during rapid and random current variation. Modifying p-q theory internal high-pass filter performance using fuzzy rules without any drawback is a prospect. In the simulated system using MATLAB/SIMULINK, the shunt active filter is connected to a rapidly time-varying nonlinear load. The harmonic detection parts of the shunt active filter are developed for FIP theory-based and p-q theory-based algorithms. The harmonic detector hardware is also developed using the TMS320F28335 digital signal processor and connected to a laboratory nonlinear load. The software is developed for FIP theory-based and p-q theory-based algorithms. The simulation and experimental tests results verify the ability of the new technique in harmonic detection of rapid changing nonlinear loads.

• Journal of Power Electronics
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• v.12 no.3
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• pp.458-467
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• 2012

Single phase converters suffer from ripple power pulsating at twice the line frequency. The ripple power is usually absorbed by a bulky capacitor bank and/or a dedicative LC resonant link, resulting in a low power density and a high cost. An alternative solution is using a dc link active power filter (APF) to direct the pulsating power into another energy-storage component. The main dc link filter capacitor can then be reduced substantially. Based on a mainstream dc APF topology, this paper proposed a new control strategy incorporating both dual-loop control and repetitive control. The circuit parameter design is also re-examined from a control point of view. The proposed APF scheme has better control performance, and is more suited for high power applications since it works in CCM and with a low switching frequency.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.4
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• pp.342-348
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• 1999

This paper describes a low-cost single-phase active power filter, which consists of a half-bridge P\A미1 inverter with a s simple control circuit. In order to verify the performance of proposed active power filter, many computer simulations w with EMTP codes and experimental works with a hardware prototype were done. Both results confirm that the p proposed active power filter shows excellent performance to eliminate the harmonics generated in the single-phase non l linear‘ load. The active power filter has advantage of low implementation cost and compact size. using a half-bridge i inverter and a simple control circuit with only one current sensor. So. it can be fabricated as a plug-in type.

• Journal of Power Electronics
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• v.10 no.4
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• pp.412-418
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• 2010

This paper proposes a new algorithm to generate a reference signal for an active power filter using a sliding-window FFT operation to improve the steady-state performance of the active power filter. In the proposed algorithm the sliding-window FFT operation is applied to the load current to generate the reference value for the compensating current. The magnitude and phase-angle for each order of harmonics are respectively averaged for 14 periods. Furthermore, the phase-angle delay for each order of harmonics passing through the controller is corrected in advance to improve the compensation performance. The steady-state and transient performance of the proposed algorithm was verified through computer simulations and experimental work with a hardware prototype. A single-phase active power filter with the proposed algorithm can offer a reduction in THD from 75% to 4% when it is applied to a non-linear load composed of a diode bridge and a RC circuit. The active power filter with the proposed reference generation method shows accurate harmonic compensation performance compared with previously developed methods, in which the THD of source current is higher than 5%.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.2
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• pp.162-168
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• 2014

Use of nonlinear loads, such as power converters, fluorescent lamps and adjustable speed motor drives, is expected to grow rapidly. All of these loads inject harmonic currents. This paper presents the active filtering of the harmonic distortion generated by the compact fluorescent lamps (CFL). The Instantaneous active and reactive power theory (the p-q Theory) is used to design the control of parallel active filter. The control scheme has been verified using Matlab/Simulink with SimPower Systems through a set of simulation tests under different load conditions. Also, the tuning of the active power filter is performed to improve the quality of the electrical power supply.

• Journal of Power Electronics
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• v.1 no.1
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• pp.9-18
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• 2001

The performance analysis of a three-phase parallel active power filter that compensates PCC voltage and the unbalanced loads is presented in this paper. The proposed scheme in this paper employs a PWM voltage-source inverter and has two operation modes. Firstly, it operates as a conventional active filter with reactive power compensation when PCC voltage is within the 15% voltage drop range. Secondly, it operates as a voltage compensator when PCC voltage is not within the 15% voltage drop range. And both APF and voltage compensator compensate asymmetries caused by nonlinear loads. Finally, two methods of detecting the negative sequence are reviewed, and the validity of this scheme is investigated through analysis of simulation and experimental results for a prototype active power filter system rate at 10KVA.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.504-506
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• 2005

This paper proposes a new neutral current reduction method using PQR instantaneous power theory on the active power filter, unbalanced nonlinear load condition in three-phase four-wire systems. For reduction of neutral line current, the single phase active power filter is used and its performance is same with the three-phase four-wire active power filter. For fully-digital implementation, ramp comparison PWM method was adopted. Simulation results verify good performance of the proposed current control strategy on the shunt APFs.

• 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.

• Journal of Power Electronics
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• v.16 no.4
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• pp.1541-1550
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• 2016

This paper presents a theoretical analysis and comparisons of active power filter (APF) and hybrid power filter (HPF) systems, given terminal constraints of harmonic compensations in nonlinear loads. Despite numerous publications for the two types of filters, the features and differences between them have not been clearly explained. This paper presents a detailed analysis of the operations of a HPF inverter along with those of passive power filters (PPFs). It also includes their effects on the power factor at the grid. In addition, a theoretical analysis and a systematic comparison between the APF and HPF systems are addressed based on system parameters such as the source voltage, output power, reactive component size, and power factor at the grid terminals. The converter kVA ratings and dc-link voltage requirements for both topologies are considered in the presented comparisons

• Proceedings of the KIEE Conference
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• 2001.04a
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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.