Research

Jump to: Review

Open AccessArticle

Harmonics and Interharmonics Detection Based on Synchrosqueezing Adaptive S-Transform

by

,

,

and

Energies 2022, 15(13), 4539; https://doi.org/10.3390/en15134539 - 21 Jun 2022

Viewed by 194

Abstract

The integration of renewable energy generation and nonlinear power electronic equipment into the grid brings about complex harmonics and interharmonics problems. The amplitude and frequency of harmonics and interharmonics should be detected by high time-frequency (T-F) resolution methods owing to their time-varying transient [...] Read more.

The integration of renewable energy generation and nonlinear power electronic equipment into the grid brings about complex harmonics and interharmonics problems. The amplitude and frequency of harmonics and interharmonics should be detected by high time-frequency (T-F) resolution methods owing to their time-varying transient features. In this paper, a synchrosqueezing adaptive S-transform (SAST) method is proposed to detect the parameters of harmonics. Firstly, the time-frequency spectrum (TFS) of the harmonic signals is acquired by an adaptive S-transform (AST) algorithm. The TFS results are then subjected to synchronous compression, so as to achieve higher time-frequency representation precision. The detection results of the simulation signals show that SAST can achieve a better time-frequency resolution than the S-transform (ST) and synchrosqueezing short-time Fourier transform (SSTFT). In addition, the application of SAST to the analysis of experimental signals also suggests its superiority in the parameter detection of harmonics, especially for the time-varying interharmonics. Full article

(This article belongs to the Special Issue Active Power Filters and Power Quality)

► Show Figures

Figure 1

Open AccessArticle

A New Optimal Current Controller for a Three-Phase Shunt Active Power Filter Based on Karush–Kuhn–Tucker Conditions

by

Krzysztof Kołek

and

Andrzej Firlit

Energies 2021, 14(19), 6381; https://doi.org/10.3390/en14196381 - 06 Oct 2021

Viewed by 485

Abstract

This paper presents an algorithm for finding the optimal control for a current controller that operates as a part of a control system of a shunt active power filter. The algorithm is based upon the Karush–Kuhn–Tucker conditions for finding an optimal value where [...] Read more.

This paper presents an algorithm for finding the optimal control for a current controller that operates as a part of a control system of a shunt active power filter. The algorithm is based upon the Karush–Kuhn–Tucker conditions for finding an optimal value where control signal is limited and constraints create a cube. The explicit solution of the Karush–Kuhn–Tucker problem is presented and simplified calculations are given to lower calculation complexity. The presented Karush–Kuhn–Tucker algorithm is compared with a classical PI controller. It is given the algorithm for finding the optimal parameters of the PI controller and the behavior of the PI controller is compared with the presented algorithm. Attention has been paid to the saturation of controllers in commutation states of load currents, which has a negative impact on the final performance of the controllers and the controlled shunt active power filter. The paper also presents the software and hardware platforms applied to run the presented algorithms in real-time. For both controllers, the shunt active power filter response is shown using real experimental results. The results of the experiments prove better behavior regarding the presented algorithm, especially in the case of commutative load currents, where the output signals from other controllers become saturated. Full article

(This article belongs to the Special Issue Active Power Filters and Power Quality)

► Show Figures

Figure 1

Open AccessArticle

Stability Analysis of Shunt Active Power Filter with Predictive Closed-Loop Control of Supply Current

by

Agata Bielecka

and

Daniel Wojciechowski

Energies 2021, 14(8), 2208; https://doi.org/10.3390/en14082208 - 15 Apr 2021

Cited by 4 | Viewed by 630

Abstract

This paper presents a shunt active power filter connected to the grid via an LCL coupling circuit with implemented closed-loop control. The proposed control system allows selective harmonic currents compensation up to the 50th harmonic with the utilization of a model-based predictive current [...] Read more.

This paper presents a shunt active power filter connected to the grid via an LCL coupling circuit with implemented closed-loop control. The proposed control system allows selective harmonic currents compensation up to the 50th harmonic with the utilization of a model-based predictive current controller. As the system is fully predictive, it provides high effectiveness of the harmonic reduction, which is proved by waveforms achieved in performed tests. On the other hand, the control system is prone to loss of stability. Therefore, the paper is focused on the stability analysis of the discussed control system with the additional outer control loop of the supply current with predictive control of this current. The conducted stability analysis encompasses the assessment of system stability as a function of the coupling circuit parameter identification accuracy, whose values are implemented in the current controller, as well as parameters such as the sampling frequency and proportional-integral (PI) controller coefficients. The obtained results show that the ranges of the LCL circuit parameter identification accuracy for which the system remains stable are relatively wide. However, the most effective compensation of the supply current distortion is achieved for the parameters identified correctly, and the greatest impact on the compensation quality has the value of L₁ inductance. Full article

(This article belongs to the Special Issue Active Power Filters and Power Quality)

► Show Figures

Graphical abstract

Open AccessArticle

On Adaptive Moving Average Algorithms for the Application of the Conservative Power Theory in Systems with Variable Frequency

by

Daniel dos Santos Mota

and

Elisabetta Tedeschi

Energies 2021, 14(4), 1201; https://doi.org/10.3390/en14041201 - 23 Feb 2021

Cited by 1 | Viewed by 732

Abstract

The Conservative Power Theory (CPT) emerged in recent decades as a theoretical framework for coping with harmonically distorted and unbalanced electric networks of ac power systems with a high participation of converter interfaced loads and generation. The CPT measurements are intrinsically linked to [...] Read more.

The Conservative Power Theory (CPT) emerged in recent decades as a theoretical framework for coping with harmonically distorted and unbalanced electric networks of ac power systems with a high participation of converter interfaced loads and generation. The CPT measurements are intrinsically linked to moving averages (MA) over one period of the grid. If the CPT is to be used in a low-inertia isolated-grid scenario, which is subjected to frequency variations, adaptive moving averages (AMA) are necessary. This paper reviews an efficient way of computing MAs and turns it into an adaptive one. It shows that an easily available variable time delay block, from MATLAB, causes steady-state errors in the measurements when the grid frequency varies. A new variable time delay block is, thus, proposed. Nonetheless, natural pulsations in the instantaneous power slip through MAs when the discrete moving average window does not fit perfectly the continuously varying period of the grid. A method consisting of weighing two MAs is reviewed and a new and effective hybrid AMA is proposed. The CPT transducers with the different choices of AMAs are compared via computer simulations of a single-phase voltage source feeding either a linear or a nonlinear load. Full article

(This article belongs to the Special Issue Active Power Filters and Power Quality)

► Show Figures

Figure 1

Open AccessArticle

Active Filter Reference Calculations Based on Customers’ Current Harmonic Emissions

by

,

,

and

Energies 2021, 14(1), 220; https://doi.org/10.3390/en14010220 - 04 Jan 2021

Cited by 1 | Viewed by 783

Abstract

This paper deals with harmonics compensation in industrial and distribution networks using an active filter (AcF). When defining the AcF’s reference current, it is important to properly consider the network background harmonic distortion. Within this paper, we propose an AcF reference current calculation [...] Read more.

This paper deals with harmonics compensation in industrial and distribution networks using an active filter (AcF). When defining the AcF’s reference current, it is important to properly consider the network background harmonic distortion. Within this paper, we propose an AcF reference current calculation method, based on customers’ current harmonic emissions. The main novelty of the paper is the AcF reference current calculation method that considers only the customer’s contributions to the harmonic distortion at the point of common coupling (PCC). By separating the harmonic current at the PCC into components that can be attributed to the customer and to the network, it is possible to limit the required AcF power. To determine the customer’s emission, the customer’s harmonic impedance must be known. As the actual harmonic impedance cannot be determined in a real environment, a reference harmonic impedance can be used instead. To test the proposed AcF reference current calculation method, we developed a control algorithm of an AcF in the PSCAD software and tested this on a medium-voltage benchmark simulation model. Full article

(This article belongs to the Special Issue Active Power Filters and Power Quality)

► Show Figures

Figure 1

Open AccessArticle

Software Solution for Modeling, Sizing, and Allocation of Active Power Filters in Distribution Networks

by

,

,

,

and

Energies 2021, 14(1), 133; https://doi.org/10.3390/en14010133 - 29 Dec 2020

Cited by 5 | Viewed by 728

Abstract

The paper is related to the problem of modeling and optimizing power systems supplying, among others, nonlinear loads. A software solution that allows the modeling and simulation of power systems in the frequency domain as well as the sizing and allocation of active [...] Read more.

The paper is related to the problem of modeling and optimizing power systems supplying, among others, nonlinear loads. A software solution that allows the modeling and simulation of power systems in the frequency domain as well as the sizing and allocation of active power filters has been developed and presented. The basic assumptions for the software development followed by the models of power system components and the optimization assumptions have been described in the paper. On the basis of an example of a low-voltage network, an analysis of the selection of the number and allocation of active power filters was carried out in terms of minimizing losses and investment costs under the assumed conditions for voltage total harmonic distortion (THD) coefficients in the network nodes. The presented examples show that the appropriate software allows for an in-depth analysis of possible solutions and, furthermore, the selection of the optimal one for a specific case, depending on the adopted limitations, expected effects, and investment costs. In addition, a very high computational efficiency of the adopted approach to modeling and simulation has been demonstrated, despite the use of (i) element models for which parameters depend on the operating point (named iterative elements), (ii) active filter models taking into account real harmonics reduction efficiency and power losses, and (iii) a brute force algorithm for optimization. Full article

(This article belongs to the Special Issue Active Power Filters and Power Quality)

► Show Figures

Figure 1

Review

Jump to: Research

Open AccessReview

A Review on Optimization of Active Power Filter Placement and Sizing Methods

by

Dawid Buła

,

Dariusz Grabowski

and

Marcin Maciążek

Energies 2022, 15(3), 1175; https://doi.org/10.3390/en15031175 - 05 Feb 2022

Cited by 2 | Viewed by 414

Abstract

Distortions of current and voltage waveforms from a sinusoidal shape are, not only a source of technical problems, but also have serious economic effects. Their occurrence is related to the common use of loads with nonlinear current-voltage characteristics. These are both high-power loads [...] Read more.

Distortions of current and voltage waveforms from a sinusoidal shape are, not only a source of technical problems, but also have serious economic effects. Their occurrence is related to the common use of loads with nonlinear current-voltage characteristics. These are both high-power loads (most often power electronic switching devices supplying high-power drives), but also widely used low-power loads (power supplies, chargers, energy-saving light sources). The best way to eliminate these distortions is to use active power filters. The cost of these devices is relatively high. Therefore, scientists all over the world are conducting research aimed at developing techniques for the proper placement of these devices, in order to minimize their investment costs. The best solution to this problem is to use optimization techniques. This paper compares the methods and criteria used by the authors of publications dealing with this topic. The summary also indicates a possible direction for further work. Full article

(This article belongs to the Special Issue Active Power Filters and Power Quality)

► Show Figures

Figure 1

Open AccessReview

A Review on Power Electronics Technologies for Power Quality Improvement

by

Joao L. Afonso

,

Mohamed Tanta

,

José Gabriel Oliveira Pinto

,

,

,

and

Energies 2021, 14(24), 8585; https://doi.org/10.3390/en14248585 - 20 Dec 2021

Cited by 1 | Viewed by 723

Abstract

Nowadays, new challenges arise relating to the compensation of power quality problems, where the introduction of innovative solutions based on power electronics is of paramount importance. The evolution from conventional electrical power grids to smart grids requires the use of a large number [...] Read more.

Nowadays, new challenges arise relating to the compensation of power quality problems, where the introduction of innovative solutions based on power electronics is of paramount importance. The evolution from conventional electrical power grids to smart grids requires the use of a large number of power electronics converters, indispensable for the integration of key technologies, such as renewable energies, electric mobility and energy storage systems, which adds importance to power quality issues. Addressing these topics, this paper presents an extensive review on power electronics technologies applied to power quality improvement, highlighting, and explaining the main phenomena associated with the occurrence of power quality problems in smart grids, their cause and effects for different activity sectors, and the main power electronics topologies for each technological solution. More specifically, the paper presents a review and classification of the main power quality problems and the respective context with the standards, a review of power quality problems related to the power production from renewables, the contextualization with solid-state transformers, electric mobility and electrical railway systems, a review of power electronics solutions to compensate the main power quality problems, as well as power electronics solutions to guarantee high levels of power quality. Relevant experimental results and exemplificative developed power electronics prototypes are also presented throughout the paper. Full article

(This article belongs to the Special Issue Active Power Filters and Power Quality)

► Show Figures

Figure 1

Open AccessReview

A Comprehensive Survey on Different Control Strategies and Applications of Active Power Filters for Power Quality Improvement

by

Soumya Ranjan Das

,

Prakash Kumar Ray

,

Arun Kumar Sahoo

,

Somula Ramasubbareddy

,

Thanikanti Sudhakar Babu

,

Nallapaneni Manoj Kumar

,

Rajvikram Madurai Elavarasan

and

Lucian Mihet-Popa

Energies 2021, 14(15), 4589; https://doi.org/10.3390/en14154589 - 29 Jul 2021

Cited by 6 | Viewed by 767

Abstract

Power quality (PQ) has become an important topic in today’s power system scenario. PQ issues are raised not only in normal three-phase systems but also with the incorporation of different distributed generations (DGs), including renewable energy sources, storage systems, and other systems like [...] Read more.

Power quality (PQ) has become an important topic in today’s power system scenario. PQ issues are raised not only in normal three-phase systems but also with the incorporation of different distributed generations (DGs), including renewable energy sources, storage systems, and other systems like diesel generators, fuel cells, etc. The prevalence of these issues comes from the non-linear features and rapid changing of power electronics devices, such as switch-mode converters for adjustable speed drives and diode or thyristor rectifiers. The wide use of these fast switching devices in the utility system leads to an increase in disturbances associated with harmonics and reactive power. The occurrence of PQ disturbances in turn creates several unwanted effects on the utility system. Therefore, many researchers are working on the enhancement of PQ using different custom power devices (CPDs). In this work, the authors highlight the significance of the PQ in the utility network, its effect, and its solution, using different CPDs, such as passive, active, and hybrid filters. Further, the authors point out several compensation strategies, including reference signal generation and gating signal strategies. In addition, this paper also presents the role of the active power filter (APF) in different DG systems. Some technical and economic considerations and future developments are also discussed in this literature. For easy reference, a volume of journals of more than 140 publications on this particular subject is reported. The effectiveness of this research work will boost researchers’ ability to select proper control methodology and compensation strategy for various applications of APFs for improving PQ. Full article

(This article belongs to the Special Issue Active Power Filters and Power Quality)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Special Issue "Active Power Filters and Power Quality"

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Published Papers (9 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI