Shunt Active Power Filter Research Articles

Discussions on the Instantaneous Reactive Power Theory Terms in the General Case Based on the Symmetric Components

This paper deals with the presentation of different terms of the powers presented in the Instantaneous Reactive Power Theory (IRPT) in the general case of a generic power system voltage. This presentation is based on the use of the symmetric components in the E. Clarke stationary frame, where the instantaneous real active power, the instantaneous imaginary reactive power and the instantaneous zero sequence power are divided into their DC components and AC components function of the symmetric components. The contributions of these terms in the transfer of the energy from the power supply to the load in four wire system are explained, hence, a good choice of the power to be compensated using shunt active power filter can be obtained. Finally, simulation results are presented under unbalanced and distorted generic power system voltages, where different terms of the instantaneous reactive power theory are clarified and presented based on symmetrical components.

Comparison of Multi-Resonant- and Hysteresis Band Controllers used in Current Control Loop of Shunt Active Power Filter

In the paper the advantages and disadvantages of both current control loops with hysteresis and resonant types are presented by simulation analyses and experimental results. The result of comparison defines some recommendations for the fields of use of shunt active power filter controlled by these regulators.

Neural-Networks and Synchronous Reference Frame Applied in the Harmonic Compensation with a Three-Phase Parallel Active Power Filter

This paper presents an alternative method based on artificial neural network, which is used to obtain the reference currents for harmonic current suppression and reactive power compensation in a shunt active power filter applied to three-phase four-wire system. The neural network consists of a multilayer perceptron, which is trained to estimate the peak amplitude of the load fundamental component currents. The performance of the proposed artificial neural network is evaluated by computer simulation, and it is compared with the method based on synchronous reference frame

A New Design of UPQC-Based Hybrid Multi-Carrier Modulation for Transformer Less Grid Connected PV-Based Active Power Filter

In recent times, there has been a growing concern over the augmented power consumption, leading to a pressing need for compensating devices to maintain power quality in grid-connected systems. One extensively employed solution is the Unified Power Quality Conditioner (UPQC), which incorporates both shunt and series active power filters (APFs) connected through a DC-link capacitor. However, traditional systems using compensating devices can be costly and cumbersome, often relying on transformers to interface with the grid. To address these drawbacks, this report proposes a transformer-less networking approach using a multi-level inverter (MLI) that reduces the number of switches in the shunt and series APF. To enable the efficient operation of the MLI in UPQC, the report utilizes Synchronous Reference Frame Theory and Hybrid Multi-Carrier Pulse Width Modulation (H-MCPWM) techniques for reference signal generation and gate control, respectively. MATLAB/Simulink simulation version 2019a is employed to validate the performance of the proposed system, along with a hardware prototype featuring a motor load. A key aspect of the investigation involves conducting harmonic analysis for various modulation indices with a non-linear load. The resulting data is then compared to the outcomes of the conventional model. By exploring this approach, the report aims to showcase the viability of the transformer-less networking of MLI in UPQC, thereby paving the way for more cost-effective and efficient grid-connected systems with improved power quality.

Robust Voltage Vector-Controlled Three-Phase SAPF-based BPMVF and SVM for Power Quality Improvement

The multiplication of nonlinear loads leads to significant degradation of the energy quality, thus the interconnection network is subject to being polluted by the generation of harmonic components and reactive power, which causes a weakening efficiency, especially for the power factor. In three-phase systems, they can cause imbalances by causing excessive currents at the neutral. This research treats the operation of robust voltage-oriented control (VOC) for a shunt active power filter (SAPF). The main benefit of this technique is to guarantee a decoupled control of the active and reactive input currents, as well as the input reference voltage. To sustain the DC voltage, a robust PI-structure-based antiwindup is inserted to ensure active power control. Besides, a robust phase-locked loop (PLL)-based bandpass multivariable filter (BPMVF) is used to improve the network voltage quality. Furthermore, a space vector modulation (SVM) is designed to replace the conventional one. A sinusoidal network current and unitary power factor are achieved with fewer harmonics. The harmonics have been reduced from 27.98% to 1.55% which respects the IEEE 519-1992 standard. Expanded simulation results obtained from the transient and steady-state have demonstrated the high performance of the suggested control scheme.

Connection of Shunt Active Power Filters in Multibus Industrial Power Systems for Harmonic Voltage Mitigation.

The bus voltage and branch current detection control strategies of the active power filters used in multibus power systems for harmonic voltage mitigation are analysed in terms of the harmonic bus voltage mitigation and of the demanded current spectrum injected by the active power filters.

Control of a Active Filter Using Dynamic Neural Networks

At this paper the “dynamic multilayer perceptron” (MLP) neural network has been applied to the control of an active power filter (APF). The objective is developing a new suitable control technique by APF’s for compensation of harmonic distortion present in nonlinear loads current by electric power circuits. The strategy has been extracting the instantaneous value of the fundamental harmonic from the load current by means of this artificial neural network (ANN) topology. A previous training with waveforms distorted by harmonics up to the 29th order showed to be enough for a high accuracy, working with typical nonlinear loads. By using this fundamental harmonic, the shunt APF reference distortion signal is obtained. This has been applied, at simulation, to a practical case of a power circuit containing an AC regulator and a series RL load. The results show the ability of this type of ANN to supply the APF with the reference signal necessary for its control.

Advanced Nonlinear Control of Shunt Active Power Filter Connected to PV System via DC/DC Converter

We address the challenge of controlling a single-phase shunt active power filter in the presence of nonlinear loads. The active power filter is linked to a photovoltaic (PV) system, which supplies active power to the load. The main control objectives are: (i) mitigation of harmonics current and reactive power induced by the non-linear load; (ii) regulation the PV generator output voltage to follow its reference provided by the Maximum Power Point Tracking (MPPT) block, (iii) regulation the DC bus voltage to a constant value that must be greater than the amplitude of the grid voltage in order to guarantee full power injection to the non-linear load. To solve this problem, we use a nonlinear multi-loop controller. The inner loop is designed using the Backstepping method to cope with compensation problems. The external loop is responsible for regulating the dc bus voltage. The DC-DC boost control loop is designed to achieve the MPPT objective. The efficiency of the proposed controller is validated by simulation in MATLAB/Simulink.

A developed DQ control method for shunt active power filter to improve power quality in transformers.

Power transformers are the most important component in power system. Exposing these transformers to the harmonic distortions causes additional heat losses, insulation stress, decrease in lifetime of insulation, and reduced power factor with decrease in efficiency of the system. The lifespan of distribution transformers is influenced by the fragility of power quality in power networks. Harmonic mitigation filters with robust control technique are required to reduce the harmonic effects on power transformer. Traditionally, synchronous reference frame (DQ) is employed to control the shunt active power filter (APF) for mitigation of harmonics in power transformers. DQ control of Shunt APF lacks merits of fast response, delayed operation due to phased lock loop under abnormal grid conditions leading to insufficient harmonic elimination. A developed DQ method based on detecting the positive and negative sequence components is proposed to precisely control the shunt APF for reliable operation of power transformer. This detection technique improves the response time, mitigate the harmonics effecting the operation of transformer and overall power factor. The proposed control system is evaluated under different abnormal operating scenarios and compared with traditional DQ method. The results and analysis confirm the efficacy of the developed DQ method in improving the power transformer performance.

Mitigation of Power Quality Issue in Hybrid Renewable Energy Source by UPQC with Optimization Techniques

This paper presents a comprehensive approach to mitigate power quality issues in hybrid renewable energy systems through the utilization of Unified Power Quality Conditioner (UPQC) integrated with optimization techniques. As renewable energy sources like wind and solar play an increasingly significant role in power generation, ensuring high-quality power supply becomes imperative. The UPQC, comprising series and shunt active power filters, is strategically deployed to address voltage fluctuations, harmonics, and other disturbances. To enhance its efficacy, advanced optimization techniques such as control algorithm optimization and parameter tuning are employed. These techniques enable the UPQC to adapt to varying operating conditions and optimize its performance in real-time. Integration with hybrid renewable energy sources is seamless, facilitating coordinated operation for optimal power quality enhancement. The proposed approach emphasizes real-time monitoring and control, enabling proactive response to power quality fluctuations and ensuring stable and reliable electricity supply. Through rigorous testing, validation, and maintenance protocols, the effectiveness and reliability of the integrated system are demonstrated. This holistic approach contribute to the stability and sustainability of modern power grids, fostering the widespread adoption of hybrid renewable energy systems.

A robust PQ-controlled three-phase SAPF-based SVM and PI anti-windup for power quality improvement

The use of power electronics devices in electrical energy conversion installations has significantly contributed to improving the performance and efficiency of these systems. On the other hand, static converters have contributed to the deterioration of the quality of current and voltage in distribution networks. These converters consume non-sinusoidal currents, and they behave like harmonic current generators. The power factor and overall system efficiency are weakened by these injected harmonics, reactive power, and other issues. Meanwhile, those loads’ harmonic difficulties must be resolved. The research presented in this paper particularly concerns the study of a shunt active power filter (SAPF) intended to compensate for the harmonic currents generated by nonlinear loads and the compensation of reactive energy. The theory of PQ control is the subject of this research. A robust structure is proposed for that purpose. To sustain the DC-link voltage at the desired interval, a robust PI-regulator-based antiwindup is inserted to ensure active power control. Besides, space vector modulation (SVM) is designed to replace classical pulse width modulation (PWM). The principal benefits of this technique are that it supplies a unitary power factor and sinusoidal network current with no requirement for a PWM generator and fewer harmonics. A comparison between the conventional and the proposed control is established to demonstrate the superiority of the PQ-SVM scheme. The comparison mainly concerns the bus voltage as it is the responsible for the whole system stability Expanded simulation results obtained from the transient and steady-state have demonstrated high performance and have confirmed the robustness and effectiveness of the suggested method.

A Robust Backstepping Controller Based on Nonlinear Observer for Shunt Active Filters to Improve Power Quality in Four-Wire Distribution Systems

This article introduces a novel approach to enhance the performance of LCL based active power filters (APFs) in four-wire distribution systems by employing a nonlinear current control strategy. The strategy combines backstepping control (BSC) and a nonlinear disturbance observer (NDOB) to effectively manage harmonic and interharmonic grid currents. By situating the shunt active power filter (SAPF) at the point of common coupling (PCC) via the LCL filter, the technique ensures that grid connected currents remain balanced and purely sinusoidal. The integration of NDOB with BSC aims to fortify the resilience of BSC against disturbances. Consequently, any disturbances occurring within the system are precisely estimated by the NDOB and subsequently mitigated through the BSC mechanism. Notably, this approach showcases robust adaptability across diverse scenarios, encompassing external disturbances, variations in filter parameters, nonlinear loads laden with harmonics and interharmonics, load imbalances, and non-ideal grid voltages. Its performance remains robust and stable even when disturbances are present. Comparative analysis with linear-based methodologies underscores the advantages of this approach, revealing quicker and smoother transient responses. The efficacy of the proposed technique is demonstrated through comprehensive simulation studies, substantiating its potential for significantly advancing power quality in complex distribution systems.

Observation and Backstepping Control of Single-Phase Shunt Active Power Filter Connected to photovoltaic System.

The present paper concentrates on the improvement of power quality using a single-phase active power filter (APF) connected to the photovoltaic (PV) array operating in the presence of a non-linear load. A novel controller design, based on the energy stored in the half-bridge shunt APF is proposed to ensure two main objectives at the same time: (i) the transfer of active power to the electrical network by extracting the maximum of active power from the PV panels and regulating the PV voltage to a reference value provided by the MPPT; (ii) the improvement of power factor correction (PFC) by compensating for the harmonic current and reactive power produced by the non-linear load using the backstepping technique and Lyapunov tools. The nonlinear controller is developed in two loops. An inner loop is constituted of a PFC regulator based on the energy stored in the APF to minimize the total harmonic distortion (THD). An outer loop uses a linear PI regulator to regulate PV array voltage. The controller also comprised an observer to estimate the voltage network, which is not accessible to measurements. The performance of the proposed controller is validated by simulation using MATLAB/Simulink.

Robust PQ-Controlled 3-Phase SAPF-based PI Anti-windup and BPMVF

This research concerns the study of a shunt active power filter intended to compensate for the harmonic currents generated by nonlinear loads. These injected harmonics significantly degrade the power factor. The PQ theory is the central point of this study. A robust phase-locked loop-based bandpass multivariable filter is developed to enhance the grid voltage. To sustain the DC-bus voltage, a PI anti-windup is placed to guarantee active power regulation. The essential purpose of this solution is to ensure a sinusoidal current with fewer harmonics and a unitary power factor. The efficiency of the proposed solution has been confirmed by the obtained results in transient and steady-state.

PV System based on Active Power Filters for Energy Quality Improvement in EV Charging Station

The rapid expansion of electric vehicle (EV) charging stations leads to significant power quality issues and an increased demand for real power. Photovoltaic (PV) generators combined with active power filters (APF) can provide a solution to these problems and support the electricity grid to meet the needs of electrical loads. In this paper, a shunt APF powered by photovoltaic panels is designed to solve both the problems of the produced electrical energy quality and the preservation of the environment, while supplying charging stations for electric vehicles. The control objectives are: to make up for the harmonics and the reactive currents absorbed by the charging stations; to cancel the neutral current; and to regulate the voltage across the PV generator to extract the maximum power. To meet this purpose, a non linear controller based on the system model is developed, using a sliding-mode technique. Furthermore, a feedforward Artificial Neural Network (ANN) technique is designed to reach the PV optimum voltage to extract the maximum power. It combines the Particle Swarm Optimisation (PSO) algorithm to compute the optimum ANN’s initial weights for improving the accuracy search of this maximum. This theoretical result is confirmed by simulations involving wide range variations of solar irradiation. The simulation results show that with the SAPF, the grid current harmonic distortion is about 0.35% while the neutral current is practically zero. However, in the absence of this filter, the THD increases to 37.85% and the neutral current takes on an amplitude of 50 A.

Impact of Converter Topology on the Shunt Active Power Filter Systems Efficiency

This paper presents the performance of shunt active power filters (Shunt APFs) which can compensate harmonic currents generated by no-linear load based on five and seven-level neural point clamped (NPC) inverters. Multilevel inverters are currently being investigated and used in several industrial applications. Their advantages include the capability to reduce the harmonic content and decrease the voltage or current ratings of the semiconductors. On the other side, fuzzy techniques are successfully employed in various industrial applications; they represent a good alternative to traditional control systems. To benefit of all these advantages an efficient control scheme for five and seven-level Shunt APF based on multi-carrier pulse width modulation (MC-PWM) and fuzzy control approaches are adopted in this work. The fuzzy controller is designed to improve compensation capability of shunt APF by adjusting the error using a fuzzy rule. The control strategy to identify the current reference uses synchronous detection method (SMD), this technique is easy to implement and achieves good performances. The numerical simulation results carried with MATLAB-Simulink and SimPowerSystems Toolbox show the effectiveness of the proposed systems and confirm the superiority of the seven-level shunt APF compared to five-level configuration system.

Shunt Active Parallel Filter, Grid Photovoltaic System

This paper introduces a study focused on managing a photovoltaic system connected to the electrical grid. The primary components of this system include solar arrays linked via a DC bus to an inverter situated on the grid side. Fluctuations in solar irradiance and temperature are swift, prompting the integration of maximum power point tracking (MPPT) within the inverter’s control mechanism. The energy produced by the photovoltaic system is fed into the grid. This transfer is achieved through a proficient DC/AC conversion process, wherein the MPPT is integrated into the inverter’s operation to regulate the levels of active and reactive power injected into the grid. The paper also delves into the employment of the Space Vector Modulation (SVM) control technique for the DC-AC inverter. It covers the implementation of a Shunt Active Power Filter (SAPF) with a three-phase four-wire configuration, consisting of four legs and adopting a split capacitor topology. Furthermore, the paper includes an exploration of the instantaneous power theory and the utilization of hysteresis block control for the SAPF. The findings of this study are demonstrated and analyzed using Matlab/Simulink software.

An optimized proportional resonant current controller based genetic algorithm for enhancing shunt active power filter performance

Current harmonics produced by nonlinear loads have destructive effects that affect the power quality of the power system and cause serious problems throughout the network. Active Power Filter (APF) is one of the best and most common solutions to reduce or eliminate harmonic disturbances; But due to the complexity and sensitivity of these filters, the accurate and fast performance of the control technologies used in it is the important and basic requirement. Therefore, by performing accurate and optimal adjustments for APF control, system performance and power quality level can be improved significantly. In this article, the design principles of Shunt Active Power Filter (SAPF) are introduced and the optimal control method of this system is explained by providing appropriate modeling. Also, as a suitable structure for the current control of the SAPF system, a Proportional-Resonant (PR) controller optimized by Genetic Algorithm (GA) is proposed. The PR controller with the capability of accurate tracking of harmonic currents and fast dynamic response is highly compatible with the SAPF system. In general, the goal is to achieve better and more appropriate performance to reduce harmonic disturbances and create a robust, faster, more accurate, flexible, stable, and optimal performance of these systems in detecting and generating compensation signals. The simulations have been done in MATLAB/SIMULINK, and also the experimental tests of this device have been done and validated in a real DSP-based SAPF. Finally, according to the results obtained under steady-state conditions with a favorable dynamic response, the Total Harmonic Distortion (THD) of the grid current has been significantly reduced from 20.2 % to 4.2 % for the R-L load and from 56.1 % to 4.5 % for the R-C load with a power factor of almost unity. These results confirm the optimal and standard performance of the proposed method.

An Advanced Control Approach for a Shunt Active Power Filter.

This paper deals with the design, analysis and simulation of a three phase three wire shunt active power filter. It compensates harmonic currents, and reactive power under balanced and unbalanced supply network. An advanced control theory based on a self tuning filter is adopted. The novelty with the control approach developed in this paper is to use a self tuning filter, which can extract directly the fundamental currents in the αβ axis with high performance. It will be proved that the new approach has a good dynamic and without any delay. Moreover, we are going to propose a PLL with a high performances when the voltages of the main are strongly unbalanced and contain harmonics. The simulation results will illustrate the good performance of this new approach, specially a better dynamic characteristics in comparison with classical extraction methods will be obtained. Finally an experimental branch for testing practically this new control approach is undergoing now and hopefully the experimental results will be presented during the conference.

State-Space Averaged Model of Three-Phase Four-Wire Shunt Active Power Filter Based on Current-Controlled VSI

This work presents a universal state-space average model of three-phase four-wire shunt active power filter based on current-controlled voltage-source inverters. In this type of inverters two topologies are commonly used, namely the Four-Leg Full-Bridge (FLFB) topology, and the Three-Leg Split-Capacitor (TLSC) topology. Combining these topologies, a third topology can be obtained, namely the Four-Leg Split-Capacitor (FLSC) topology. This last topology exhibits very interesting characteristics for active filter applications. By means study of FLSC topology a state-space average model can be obtained, which will allow long-time simulations with a low cost of computation time. The behaviour of FLFB and TLSC converters can be obtained as particular cases of this universal model. Likewise, a generic technique for injected current control is proposed, offering as main advantage a decoupled control of the different legs, so full-bridge converters can be implemented without using space-vector based current control techniques.