Comparative Evaluation of Harmonic Extraction Techniques for Three-Phase Three-Wire Active Power Filter
01 Nov 2007-pp 1700-1706
TL;DR: In this article, the performance of four harmonic extraction algorithms for active power filters are evaluated based on their steady state and dynamic performance, and it is shown through simulation results that the dynamic behaviour of the harmonic extraction approach has an effect on the active power filter ratings.
Abstract: In this paper the performance of four harmonic extraction algorithms for active power filters are evaluated based on their steady state and dynamic performance The techniques which are considered for comparative study are (i) filtering approach using the conventional low pass filter, (ii) instantaneous real and imaginary power (pq) theory, (iii) instantaneous active and reactive currents method (dq), and (iv) nonlinear least squares (NLS) estimation method Comparison is based on simulation studies carried out in SABER It is shown through simulation results that the dynamic behaviour of the harmonic extraction approach has an effect on the active power filter ratings The simulation study reveals the superiority of the nonlinear least squares approach This method provides good dynamic response and also extracts the load current harmonics explicitly
Citations
More filters
TL;DR: In this article, a nonlinear least squares method for measuring the power system frequency is presented, wherein the voltage at the measurement point is modeled by using the Fourier series. But the robustness of this algorithm with respect to change in various parameters is studied through simulation and the results are validated by hardware implementation using a Virtex IV field-programmable gate array.
Abstract: This paper presents a nonlinear least squares method for measuring the power system frequency, wherein the voltage at the measurement point is modeled by using the Fourier series. The estimation of the fundamental frequency is a nonlinear problem in this formulation and is solved by performing a 1-D search over the range of allowed frequency variation. The voltage signal is used for frequency estimation because it is typically less distorted than the line current, resulting in computational efficiency. The robustness of this algorithm with respect to change in various parameters is studied through simulation and the results are validated by hardware implementation using a Virtex IV field-programmable gate array. An application of this algorithm to a shunt active power filter is also presented.
100 citations
13 Jul 2003
TL;DR: In this paper, a unified power signal processor (PSPPSP) is proposed for use in various applications in power systems, which is capable of providing a large number of signals and pieces of information which are frequently required for control, protection, status evaluation and power quality monitoring of power systems.
Abstract: This paper presents a unified power signal processor (PSP) for use in various applications in power systems. The introduced PSP is capable of providing a large number of signals and pieces of information which are frequently required for control, protection, status evaluation, and power quality monitoring of power systems. The PSP receives a set of locally measured three-phase voltage and current signals and provides their fundamental components, amplitudes, phase angles, frequency, harmonics, instantaneous and stationary symmetrical components, active and reactive currents and powers, power factor, and the total harmonic distortion. Simplicity and integrity of its structure as well as its robustness with respect to internal parameters and external disturbances and noise render the proposed scheme very attractive for practical implementations.
17 citations
06 Jun 2012
TL;DR: In this paper, a comparative study of five signal generation methods used in instantaneous theory is presented, i.e., p-q method, modified p-Q method, d-q, q-r method and vectorial with three types of signal generation namely, carrier current control, hysteresis current control and space vector modulation control.
Abstract: Instantaneous reactive power theory was the most popular control theory used when dealing with harmonics compensations. In conjunction with the instantaneous theory, switching signal generation techniques plays an important role to ensure the correct compensation signal injected in the system. Therefore, this paper discussed on comparative study of five (5) methods used in instantaneous theory namely; p-q method, modified p-q, d-q method, p-q-r method and vectorial with three (3) types of signal generation namely; carrier current control, hysteresis current control and space vector modulation control. Continuous reductions of the total harmonics distortion (THD) are expected at the supply current when applied different types of switching technique. The comparison was examining using MATLAB/Simulink (MLS) environment.
9 citations
01 Mar 2019
TL;DR: A dual Self-Tuning Filter based controller is proposed to overcome limitations in SAPF and the hardware cosimulation using ZedBoard Zynq-7000 Development Board is carried out to validate the simulation results.
Abstract: The use of power electronic devices injects harmonics into the grid causing serious power quality problems. To limit the current harmonics in accordance with IEEE Std 519, Shunt Active Power Filter (SAPF) may be used. Instantaneous power theory (pq theory) is widely used for current harmonic mitigation in SAPF. The Low Pass Filter (LPF) is used in pq theory based controllers for fundamental component extraction. The drawbacks of LPF are additional phase delay at the fundamental frequency and presence of lower frequency oscillations. A dual Self-Tuning Filter based controller is proposed to overcome these limitations. The simulation studies under different system conditions are carried out using MATLAB/SIMULINK to verify the effectiveness of the proposed method. The hardware cosimulation using ZedBoard Zynq-7000 Development Board is carried out to validate the simulation results.
5 citations
Cites methods from "Comparative Evaluation of Harmonic ..."
...From literature, it is observed that the pq method uses a low pass filter (LPF) [9] for fundamental component extraction....
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...Fig 3 shows the frequency response of LPF for fundamental frequency of 50Hz....
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...The limitations of LPF are phase delay at fundamental frequency and presence of lower frequency oscillations....
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TL;DR: In this paper, a shunt-connected harmonic current compensator is proposed to reduce the total harmonic distortion of input current of three-phase diode and SCR phase-controlled rectifiers operating with inductive loads, by matching them to the specific converter as a combined package.
Abstract: Three-phase converters using diode or silicon-controlled rectifier (SCR) are widely employed to convert the commercial AC supply to DC. Such converters inject harmonics into the power supply system and thereby distort supply system voltage waveform. A simple input current wave-shape improvement technique using a shunt-connected harmonic current compensator is presented in this work, intended to reduce the total harmonic distortion (THD) of input current of three-phase diode and SCR phase-controlled rectifiers operating with inductive loads, by matching them to the specific converter as a combined package. The compensator proposed here comprises of a three-limb voltage source converter using insulated-gate bipolar transistor, working on instantaneous current and voltage measurements of the compensator only and not of the load. The technique uses a simple feedforward control for AC source current harmonic compensation of rectifiers without monitoring the AC line currents, i.e. use of online computat...
1 citations
References
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TL;DR: The Fundamentals of Statistical Signal Processing: Estimation Theory as mentioned in this paper is a seminal work in the field of statistical signal processing, and it has been used extensively in many applications.
Abstract: (1995). Fundamentals of Statistical Signal Processing: Estimation Theory. Technometrics: Vol. 37, No. 4, pp. 465-466.
14,342 citations
TL;DR: In this paper, a new instantaneous reactive power compensator comprising switching devices is proposed, which requires practically no energy storage components, and is based on the instantaneous value concept for arbitrary voltage and current waveforms.
Abstract: The conventional reactive power in single-phase or three- phase circuits has been defined on the basis of the average value concept for sinusoidal voltage and current waveforms in steady states. The instantaneous reactive power in three-phase circuits is defined on the basis of the instantaneous value concept for arbitrary voltage and current waveforms, including transient states. A new instantaneous reactive power compensator comprising switching devices is proposed which requires practically no energy storage components.
3,331 citations
"Comparative Evaluation of Harmonic ..." refers methods in this paper
...In this method the cancellation references ia*, ib*, and ic are obtained from the instantaneous active power p and reactive power q [2]....
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...The algorithms that are considered for comparative study are (i) filtering approach using the conventional low pass filter [1], (ii) instantaneous real and imaginary power (pq) theory [2], (iii) instantaneous active and reactive currents theory (dq method) [3], and (iv) the NLS method [9]....
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...In [2] the harmonics are extracted based on the instantaneous real and reactive power (pq) theory....
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TL;DR: Experimental results obtained from a 5 kVA prototype confirm the feasibility and the features of the proposed active power filter, which can compensate the reactive power and the current harmonic components of nonlinear loads.
Abstract: The performance and dynamic characteristics of a three-phase active power filter operating with fixed switching frequency is presented and analyzed in this paper. The proposed scheme employs a PWM voltage-source inverter and has two important characteristics. First, it operates with fixed switching frequency, and second, it can compensate the reactive power and the current harmonic components of nonlinear loads. Reactive power compensation is achieved without sensing and computing the reactive component of the load current, thus simplifying the control system. Current harmonic compensation is done in time domain. The principles of operation of the proposed active power filter along with the design criteria of the power and control circuit components are discussed in detail. Finally, experimental results obtained from a 5 kVA prototype confirm the feasibility and the features of the proposed system. >
302 citations
"Comparative Evaluation of Harmonic ..." refers background or methods in this paper
...The algorithms that are considered for comparative study are (i) filtering approach using the conventional low pass filter [1], (ii) instantaneous real and imaginary power (pq) theory [2], (iii) instantaneous active and reactive currents theory (dq method) [3], and (iv) the NLS method [9]....
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...In [1] the authors use a low pass filter to obtain the harmonics....
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...Several methods have been proposed for extracting the harmonic content [1]-[9]....
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...When this fundamental component is subtracted from the original current waveform, the harmonic part of the current is obtained [1]....
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TL;DR: In this article, a Hopfield type feedback neural network is proposed for real-time monitoring and analysis of harmonic variations in the power system, where the supply-frequency variation is handled separately from the amplitude/phase variations, thus ensuring high computational speed and high convergence rate.
Abstract: With increasing harmonic pollution in the power system, real-time monitoring and analysis of harmonic variations have become important. Because of limitations associated with conventional algorithms, particularly under supply-frequency drift and transient situations, a new approach based on nonlinear least-squares parameter estimation has been proposed as an alternative solution for high-accuracy evaluation. However, the computational demand of the algorithm is very high and it is more appropriate to use Hopfield type feedback neural networks for real-time harmonic evaluation. The proposed neural network implementation determines simultaneously the supply-frequency variation, the fundamental-amplitude/phase variation as well as the harmonics-amplitude/phase variation. The distinctive feature is that the supply-frequency variation is handled separately from the amplitude/phase variations, thus ensuring high computational speed and high convergence rate. Examples by computer simulation are used to demonstrate the effectiveness of the implementation. A set of data taken on site was used as a real application of the system.
254 citations
"Comparative Evaluation of Harmonic ..." refers background in this paper
...The neural network approach [4]-[6] tracks the references currents without delay, but it requires large number of data for training....
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IBM1
TL;DR: A salient analog phase-locked loop (PLL) that adaptively controls the loop bandwidth according to the locking status and the phase error amount that achieves fast locking and minimizes output jitters.
Abstract: This paper presents a salient analog phase-locked loop (PLL) that adaptively controls the loop bandwidth according to the locking status and the phase error amount. When the phase error is large, such as in the locking mode, the PLL increases the loop bandwidth and achieves fast locking. On the other hand, when the phase error is small, this PLL decreases the loop bandwidth and minimizes output jitters. Based on an analog recursive bandwidth control algorithm, the PLL achieves the phase and frequency lock in less than 30 clock cycles without pre-training, and maintains the cycle-to-cycle jitter within 20 ps (peak-to-peak) in the tracking mode. A feed forward-type duty-cycle corrector is designed to keep the 50% duty cycle ratio over all operating frequency range.
253 citations