Mitigation Of Current Harmonics Research Articles

Synthetic Vectors-Based Predictive Control of Dual Three-Phase PMSMs for Current Harmonics Mitigation Considering Average Deception Effect

Synthetic Vectors-Based Predictive Control of Dual Three-Phase PMSMs for Current Harmonics Mitigation Considering Average Deception Effect

Design and Implementation of Single-Phase Grid-Connected Low-Voltage Battery Inverter for Residential Applications

Integrating residential energy storage and solar photovoltaic power generation into low-voltage distribution networks is a pathway to energy self-sufficiency. This paper elaborates on designing and implementing a 3 kW single-phase grid-connected battery inverter to integrate a 51.2-V lithium iron phosphate battery pack with a 220 V 50 Hz grid. The prototyped inverter consists of an LCL-filtered voltage source converter (VSC) and a dual active bridge (DAB) DC-DC converter, both operated at a switching frequency of 20 kHz. The VSC adopted a fast DC bus voltage control strategy with a unified current harmonic mitigation. Meanwhile, the DAB DC-DC converter employed a proportional-integral regulator to control the average battery current with a dynamic DC offset mitigation of the medium-frequency transformer’s currents embedded in the single-phase shift modulation scheme. The control schemes of the two converters were implemented on a 32-bit TMS320F280049C microcontroller in the same interrupt service routine. This work presents a synchronization technique between the switching signal generation of the two converters and the sampling of analog signals for the control system. The prototyped inverter had an efficiency better than 90% and a total harmonic distortion in the grid current smaller than 1.5% at the battery power of ±1.5 kW.

Comparison of APF and STATCOM for Current Harmonic Mitigation

The application of solid-state electronic devices has recorded a geometric increase in the last decade. Devices such as battery charging systems, inverters, switch mode power supplies and a host of electronic-based devices referred to as non-linear loads distort the source signal (particularly the current). Harmonics distortion imposes a severe impact on the well-being of the power system. They cause excessive device heating, reduced performance efficiency, early insulation failure, decreased dynamic torque in rotating systems, etc. This paper bases a study on Active Power Filter (APF) and Static Synchronous Compensator (STATCOM) for mitigation of these distortive harmonics in a system of 3-phase 11kV/400V, 400kVA feeding a system of non-linear loads. The study is based on the IEEE519 standard limits for current harmonics measured at the PCC. Therefore, the system short circuit ratio (SCR) is first determined. Using synchronous reference frame and instantaneous reactive power theories, the APF and STATCOM are respectively designed and run using MATLAB/Simulink software. The result analysis is obtained from the FFT signal processing toolbox of the software, and the device’s performances are evaluated based on the set standard. Results from the FFT spectra showed that the model system contains a considerable number of harmonics before filtering. However, when these devices are connected to the system, all higher-order harmonics have been minimized to the least fractions with respect to the standard, with STATCOM giving a comparatively better performance.

Mitigation of PQ issues in EV charging station connected distribution system using novel RSMLI-based shunt APF

<span>In the present scenario, the significant use of electric vehicles (EVs) is growing rapidly in the automotive industry due to cheaper transportation, no fossil fuel required, low maintenance, no fuel cost, and low impacts on the environment over the formal internal combustion engine (ICE) vehicles. In actuality, these EVs are powered by batteries that are charged by a utility-grid-based charging facility. A power-electronic conversion-based charging device is used in this charging station to charge the battery packs in the EV system. The problem statement of this work is identified, these conversion devices in charging units proliferate the power quality of the utility grid. To overcome these problems, a classical square-wave inverter-based active power filter (APF) is employed. The major problems in classical inverters are high common-mode voltage, more harmonic profile, high dV/dt stress, high switching stress, and low efficiency. The contribution of this work is proposing the multilevel inverter (MLI) based APF for better compensation over classical inverters. In this approach, a novel reduced-switch MLI-based APF has been proposed for the mitigation of harmonic currents and also enhances the power factor in utility-grid-connected distribution systems. The effectiveness of the proposed reduced-switch multilevel inverter (RSMLI)-APF is validated by integrating the number of charging units with the MATLAB/Simulink tool, and simulation outcomes are shown along with comparisons.</span>

A modified hysteresis current controller with DFCEA for current harmonic mitigation using PV-SHAPF

ABSTRACT A Modified Hysteresis Current Controller (MHCC) with Dual Fundamental Component Extraction Algorithm (DFCEA) is presented in this paper. Its purpose is to improve the current harmonics mitigation performance of a three-level T-type inverter-based Shunt Active Power Filter (SHAPF) while operating under non-sinusoidal voltage conditions. The DFCEA is responsible for isolating the fundamental voltage and current components that are necessary for synchronizing each phase and producing the reference current. The existing dual fundamental component extraction technique is updated in order to create the optimized reference currents that are required by the proposed PV-linked T-Type inverter-based Shunt Active Power Filter (PV-SHAPF). This was done in order to meet the requirements of the PV-SHAPF. It is also anticipated that it is excellent at extracting reference currents even under situations of voltage that are not optimum. To maintain the dc-link capacitor voltage at 600 V, a control algorithm of the dc-link capacitor known as the ‘DC link voltage controller’ is used. Both control algorithms are tested in a three-phase T-Type inverter-based PV-SHAPF by simulating them in a MATLAB/Simulink environment. The performance of the MHCC-DFCEA that was designed to mitigate current harmonics was proven by the findings that were gathered.

TLBO-trained ANN-based Shunt Active Power Filter for Mitigation of Current Harmonics

The increased utilization of nonlinear devices is resulting in damage to power distribution infrastructure by introducing harmonics into power system networks, which in turn causes distortion in voltage and current signals. A novel solution called Shunt Active Power Filter (SAPF) has been developed to address this issue using power electronics. This study aims to provide a method that is efficient and cost-effective for lowering harmonics and improving power quality in distribution infrastructure. The proposed method combines the Teaching learning-based optimization (TLBO) technique with an Artificial Neural Network Controller (TLBO-ANN) in conjunction with SAPF. The primary objective of the TLBO-ANN algorithms in SAPF is to minimise total harmonic distortion (THD) for maximum system efficiency. Initially, Gain values (Ki, Kp) for a regular Proportional-Integral controller are optimised with the Particle Swarm Optimisation (PSO) technique. Those optimized parameters obtained from the PSO-tuned PI controller serve as input and target datasets for training the ANN controller. Subsequently, the TLBO algorithm is utilized to further refine the ANN controller by finding the optimal weight and bias values. Using MATLAB/SIMULINK software, we compare the performance of the proposed algorithm to that of the PSO-tuned PI controller and traditional PI controller. The findings from the simulation suggest that a SAPF utilizing a TLBO-trained ANN controller could improve THD in the supplying current while maintaining harmonics within IEEE-519 accepting levels.

Mitigation of Grid Current Harmonics by ABC- ANN based Shunt Active Power Filter

Harmonics are being introduced into power system networks as a result of the increasing use of nonlinear devices. These harmonics cause distortion of current and voltage signals, which in turn causes damage to power distribution systems. As a result, the suppression of harmonics is of extreme significance in power systems. This paper proposes Shunt Active Power Filters (SAPF) based on neural network algorithms like Artificial Neural Network (ANN) as a feasible approach to mitigating harmonic distortion and raising power quality in electrical distribution systems. This research shows that using shunt active power filters (SAPF), which use the Artificial Bee Colony Optimized Artificial Neural Network Controller (ABC-ANN), is an efficient method for enhancing power quality and minimizing harmonic distortion in distribution systems. The ABC-ANN algorithms have been produced for SAPF with the goal of improving system performance by reducing Grid current Harmonics .In the first stage of this work, PSO Technique is used to tune a standard PI controller to its optimum gain values (Ki ,Kp). Then, these target and input data of PSO tuned PI controller will be supplying inputs to the ANN controller. To find the optimal weight and bias values, this ANN controller has been tuned with the help of the ABC algorithm. Using MATLAB/SIMULINK software, we compare the performance of the proposed algorithm to that of other optimization algorithm like Differential Evaluation (DE) algorithm, as well as the PSO tuned PI controller and traditional PI controller. The findings from the simulation suggest that a SAPF utilizing an ABC trained ANN controller could improve THD in the supplying current while maintaining harmonics within IEEE-519 accepting levels.

Current Harmonic Mitigation Using D-STATCOM

Increase of rectifiers for converting AC current to DC current can increase current harmonic in grids. These rectifiers can be Diode rectifiers or Thyristor based rectifiers used for variable speed drives or other applications. Then, a filter should be used to reduce these harmonic components. In this project, a Voltage Source Converter (VSC) is used as distributed static var compensation (D-STATCOM) to mitigate current harmonic produced by rectifiers. This Power quality issue is introduced, and its IEEE standard is discussed. Then its source and effect on grid is studied and simulation results are shown. Finally, a VSC D-STATCOM is used for mitigation of current harmonic in power systems.

Adaptive Interval Type II Fuzzy Logic Controller with Interface Inductor Bank Pulse Generator Based Three-Phase Four-Wire DSTATCOM Device for Power Quality Improvement

It goes without saying that the electrical distribution system is facing many power-quality issues these days. The main cause of these issues is the wide spread of nonlinear load integrated with the electrical distribution system. Moreover, the DSTATCOM device with interface inductor has different control algorithms. These encompass proportional integral controller, Interval type I fuzzy logic and interval type II fuzzy logic along used for improving the power quality issues. Before integration with the electrical distribution grid, these controllers need the tune processing. The combination of DSTATCOM with the load, which is different from the tuned one, and the wrong selection of the interface inductor leads to the failure of DSTATCOM device in the mitigation of source current harmonics. This study suggests that the use of adaptive interval type II fuzzy logic with the interface bank pulse generator based DSTATCOM device with self-tunning process and self-selection of the interface inductor would be suitable for all load types integrated into the distribution system within the rated power of DSTATCOM device. The adaptive interval type II fuzzy logic with the interface bank pulse generator based DSTATCOM device mitigates the source current harmonics and gives fast DC capacitor bus voltage response. Employing the suggested control algorithm based DSATCOM device makes the DC capacitor voltage signal settling time at almost 50 ms and total harmonic distortion of the source current at almost 4% for all cases of the load connected with the distribution system within the rated power of DSTATCOM device.

A Multiobjective Control Strategy for Harmonic Current Mitigation With Enhanced LVRT Operation of a Grid-Tied PV System Without PLL Under Abnormal Grid Conditions

This article proposes a novel multiobjective control strategy (MOCS) for improving the performance of grid-tied photovoltaic (GTPV) system without phase-locked loop (PLL) operating under abnormal grid voltage conditions such as harmonically distorted voltages, grid faults, and weak grid. The proposed control strategy effectively mitigates the harmonics in grid injected current, eliminates the oscillations in grid injected power, and enhances the low-voltage ride-through (LVRT) capability simultaneously during abnormal grid conditions. The LVRT capability of the GTPV system is enhanced by incorporating an active power regulator (APR) with dynamic reactive power support (DRPS) controller in the proposed control strategy. The proposed MOCS is designed in the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\alpha \beta $ </tex-math></inline-formula> stationary reference frame. Furthermore, the proposed MOCS consists of an advanced phase compensated multiresonant (APCMR) current controller and a phase-shifted reference current generator (PSRCG) integrated with the APR with DRPS controller. The APCMR suppresses the grid current harmonics under weak and distorted grid voltages and the PSRCG eliminates active and reactive power oscillations at the grid side caused by grid faults. The synchronization mechanism of the GTPV system is included in the PSRCG, and therefore, the requirement of PLL is avoided. Consequently, the associated computational burden on the digital controller is reduced. The effectiveness of the proposed control strategy is validated using the OPAL-RT digital simulator and offers superior performance compared to the conventional control strategy (COCS).

Power quality performance enhancement by PV-based distribution static compensator under incremental conductance maximum power point tracking algorithm

In this work, a PV-based Distribution Static Compensator (DSTATCOM) system has been integrated into the three-phase grid having linear/non-linear loading conditions. The complete DSTATCOM system has two stage converters i.e., DC-DC converter and voltage source converter (VSC). DC-DC converter has been controlled by the Incremental Conductance based MPPT algorithm while the voltage source converter has been controlled by the power balance theory (PBT)/ unit vector template (UVT) technique. These two converters are coupled with a DC link and connected at the common intersection point of the grid. The complete PV-based DSTATCOM system along with the grid has been developed and executed in the MATLAB/Simulink platform. The power quality performances have been observed in terms of DC voltage regulation and grid current harmonics mitigation for linear/non-linear loading conditions. Moreover, the THD regulation for the grid current has been verified by the IEEE 519–2014 and IEC 6100–3–2 standard.

Mitigation of supply current harmonics in fuzzy-logic based 3-phase induction motor

&lt;span lang="EN-US"&gt;A parallel active power filter is employed to enrich the quality of power in the power grid with non-linear loads. The induction motor drive requires better performance in many applications. The overall performance enhancement is performed by mitigating the delivery of current harmonics and related warmness losses in an induction motor. In this paper, comprehensive performance evaluation of a 3-phase induction motor is mentioned with fuzzy logic controller-based shunt active filter (SAF), and the outcomes are compared with proportional integral (PI) and proportional derivative controller (PID) controller. In this work, a new scheme of shunt active filters is connected at the supply side of the vertical speed indicator VSI fed induction motor. The simulation was performed by a fuzzy logic controller (FLC) based 3-&lt;/span&gt;&lt;span lang="EN-US"&gt;f&lt;/span&gt;&lt;span lang="EN-US"&gt; induction motor drive (IMD) using parallel SAF. Simulation result from MATLAB/Simulink software has been presented to understand the reduction in harmonics by introducing an active filter near the supply side. A fuzzy suitable judgment controller is brought on this work to develop the induction motor dynamic response. Analysis of the simulation outcomes, the usage of MATLAB/Simulink software program for the proposed FLC managed induction motor had been demonstrated and overall performance enhancement of induction motor was discussed.&lt;/span&gt;

Coupling Effect Analysis and Design Principle of Repetitive Control Based Hybrid Controller for SVG With Enhanced Harmonic Current Mitigation

Static var generator (SVG) is mostly utilized under polluted grid conditions with certain power quality problems, of which the grid disturbance will lead to the distortion of grid-side current. Hybrid repetitive controller (RC), as an effective method to suppress periodic distortion of grid-connected converters and to improve the dynamic response of conventional RC, has been adopted in existing approaches. However, the physical meaning of existing modeling based on the small gain theorem is not clear. Besides, the conventional design method is difficult to reveal the stability domain and to obtain an optimized repetitive gain, which influences the anti-disturbance performance. In this article, the coupling effect among the controllers of hybrid RC is revealed, showing clear physical meaning, thus the mechanism resulting in the instability problem and delay effect is addressed clearly. Different from existing methods, a simpler design principle is proposed, and a universal stability domain analysis for hybrid RC can be directly obtained and ensure a maximized repetitive gain. A proportional, resonant, and RC (PR-RC) is given as an example to improve the dynamic response of the SVG under <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$a$ </tex-math></inline-formula> – <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$b$ </tex-math></inline-formula> – <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$c$ </tex-math></inline-formula> coordinate. Experimental results demonstrate the correctness and effectiveness of the coupling analysis and parameter design.

Enhanced Power Quality PV Inverter With Leakage Current Suppression for Three-Phase SECS

This article presents an enhanced power quality solar photovoltaic (PV) inverter enabling common-mode leakage current elimination. A three-phase transformerless solar energy conversion system is considered here, which, along with peak active-power production from PV array, ensures different power quality improvement capabilities such as grid current harmonics mitigation, grid currents balancing while also offering the grid reactive power support. Unlike conventional power quality inverters, this strategy is robust with respect to abnormalities in grid voltages at far radial ends, and does not compromise with the leakage currents caused by parasitic capacitance of PV array with ground. Common practice in the PV inverter power quality control is to neglect the PV leakage currents; however, they considerably affect the system performance by deteriorating the power quality and causing the safety issues of operating personnel. The standards VDE-00126 and NB/T-32004, therefore, compel the transformerless PV systems to operate with leakage current under 300 mA range. Various simulation and test results show the satisfactory performance of the presented strategy, even under various grid-side abnormalities. The comparative analysis with the state-of-the-art techniques shows the effectiveness of the strategy. Under all test conditions, the harmonics in grid currents are observed within limits as per the IEEE-519 and IEC-61727 standards, whereas the PV leakage currents are maintained well within the range recommended by VDE-00126 standard.

Reduction of power conversion losses in AC-DC coupled hybrid micro-grid under grid distorted voltage scenario

As the power consumption rate is high, the supply from fossil fuels is not enough to meet consumer demand. Further, the depletion of fossil fuels and environmental concern forces the extraction of power from low carbon fuels causes generation problems due to its uncertainty and intermittent in nature. So, low carbon fuels such as wind, solar, etc. can therefore, be incorporated into a more efficient hybrid micro-grid system. In the current dominated AC coupled hybrid micro-grid system, a significant amount of power conversion losses is increased due to more power conversion stages. Therefore, this research paper proposes an appropriate loss calculation method (i) to validate AC-DC coupled hybrid micro-grid system has minimum power conversion losses than the AC coupled hybrid micro-grid system, (ii) appropriate power sharing between AC and DC bus and (iii) grid current harmonics mitigation. To validate this method, different case studies are performed in MATLAB simulation by considering undistorted and distorted grid conditions with variation in renewable energy sources. The observed results demonstrate that the merits of the AC-DC coupled hybrid micro-grid system has been validated over AC coupled hybrid micro-grid system.

Evaluation of the VLSS-LMS Method Parameters’ Influence on the Effective Estimation of Power System Current and Voltage Harmonics Content

Nowadays, power quality is considered as a major concern that is faced by electrical energy producer, consumers, industries and researchers. Whereas one among the main issues in such concern is the current and voltage harmonics detection, mitigation and compensation. Indeed, the proliferation of harmonics in power system can create serious problems within all levels and their impacts along the whole power system from the production to the end users can lead to critical technical and economic situations. Therefore, their accurate detection in real time is of great importance and interest where many techniques have been proposed for solving such major problem. The work presented in this paper deals with the evaluation of a technique that has been proposed for the estimation of harmonic content in a signal based on iterative computing technique. This technique is based on several keystone parameters, which have major influences on the accuracy of the identification of the different harmonics without the need of a costly computation, and that can be easily implemented and performed in real-time. It is worthy to clarify that the technique under investigation in this paper is the based on the idea of adaptive filtering process called the Variable length Step Size- Least mean squares method (VLSS-LMS), it is basically very sensitive to three main parameters such as the sampling frequency, the step size value and the measurement window. The evaluation of the effects of these parameters have been assessed based on simulation testes of a specific original signal containing harmonics components. The obtained simulation results clearly prove the optimal choices of the aforementioned parameters in ensuring precise estimation of the harmonics content and the reconstruction of the estimated signal with high precision and minimized average error.

DC Component Extraction of Notch Filter Algorithm for Active Power Filters

This work presents a way to handle the DC component of input signals for PLL and notch filter applications, which are utilized for filtering and synchronization. The input signal of a DC component may be due to some sort of malfunction, or it may be the result of the structure and restrictions of the measurement/conversion procedures. This part makes the system's loop oscillate at low frequencies and no filter can fully filter them out because that would significantly harm the system's dynamic response. The proposal involves augmenting the PLL structure with a new loop. It is basic architecturally and in contrast to a currently presented method and it does not detract from the algorithm's high-frequency filtering level. This Orthogonal Signal Generators (OSG) control algorithm is used for active power filter to maintain unity power factor, neutral current compensation using star/three single transformer &amp; current harmonics mitigation. The MATLAB/Simulink results are demonstrated for the above stated Power Quality (PQ) problems.

Mitigation of current harmonics in multi-drive system

Most of the fully automated industries are mainly depending on the single and multi-drive system based on their requirements. In this paper, to investigate the power quality problems in a distributed multi drive system connected to the common uncontrolled rectifier is considered. Uncontrolled rectifier is mainly used as a front-end converter to feed direct current (DC) supply to the same rating of two voltage source inverters with induction motors as a multi-drive system. To analyse the effectiveness of the system the two drive systems are operated in different time period. Then, both are operated simultaneously to monitor the power quality issues, due to the front-end converter present in the system. In both the cases the harmonics in source current is not within the limits of IEEE recommended practices. Therefore, to reduce the harmonic content present in the current at source, a shunt active power filter is implemented. The effect of two drive systems operated at the same time is analysed first. Then, active filter is injected in between the source and the multi-drive system in parallel to improve the power quality of the grid system. The individual and multi-drive drive systems are analysed with the simulation results.

Unit Partition Resonance Analysis Strategy for Impedance Network in Modular Power Converters

In modular power converters, the dc-link capacitor has the highest failure rate due to thermal stress, reducing system performance and reliability. Current harmonics are one of the prominent causes of thermal stress on the dc-link capacitor that may get instigated by the resonance between the dc-link capacitor and stray inductance of the busbar. The dc-link capacitor current harmonics mitigation through busbar design optimization has not been reported. The challenge lies in analyzing the profound resonance characteristics of high order dc-link busbar impedance network as no insightful information can be obtained from impedance analyzers. This paper features a new strategy for high power modular converters that splits the high order dc-link busbar impedance network into corresponding lower-order sub-units. Then, the required relationship between resonating components and corresponding resonance frequencies is attained by exploiting the structural symmetry of the standard modular power unit as well as the inheritance relationship between sub-circuit units and the combined network. Finally, leveraging the derived resonant frequencies expressions, busbar structure is optimized, and up to 23% reduction in capacitor RMS current is achieved. Simulation and experimental results are provided to validate the efficacy of the proposed analysis method. The in-depth theoretical study featured in this paper can dictate not only the busbar design optimization but also a key to improve capacitor lifetime and reliability of the system.

THE UNIFIED POWER QUALITY CONDITIONER: A REVIEW

This thesis addresses the Unified Power Quality Conditioner (UPQC) which is a major custom power solutions capable for load balancing, power factor-correction, voltage regulation, voltage and current harmonics mitigation in a three-phase three-wire distribution system for different combinations of linear, non-linear and dynamic loads. The unit template technique (UTT) is used to get the reference signals for series active power filter and shunt active power filter which utilizes two closed loop PI controllers. The design of three- phase three-wire UPQC includes the design of shunt controller (SHUC) and series controller (SERC).