Voltage Distortion Research Articles

Different LC power filter topologies - effectiveness of reducing voltage distortion

This Paper aims to present a comparative study of different passive filter configurations. Five topologies of passive RLC filters for the purpose of the mitigation of harmonics voltage distortion are considered. Basis for evaluating the effectiveness of different filter topologies are simulation and laboratory studies.

ANFIS controlled fuel cell powered series active filter for voltage waveform augmentation in the distribution grid

The high penetration of nonlinear and unstable loads into the grid network severely impacts the quality of power delivered by the grid system. Furthermore, it leads to a disruptive situation of maintaining good quality power in the distribution sectors. Consequently, maintaining a good quality of power is very difficult on the power distribution grid. In this proposed work, the Proton exchange membrane Fuel Cell sustained by a three-phase Series Active Filter (PFC-SAF) is employed to enhance the quality of sensitive load voltage in the distribution grid. The generalized bell-shaped membership function based on the Adaptive Neuro-Fuzzy Inference System (ANFIS) is used to generate the reference voltage signals of the PFC-SAF. The proposed system is modelled and analyzed in a Matlab/Simulink environment. The performance of the PFC-SAF is investigated based on various fault conditions and voltage harmonics. From the obtained results, it has been found that the PFC-SAF effectively regulates the voltage in the distribution grid. Also, the total harmonic distortion of the sensitive load voltage is reduced from 20.86 % to 0.55 %.

A Comprehensive Survey on Harmonic Elimination in Multilevel Inverters Using Optimization Techniques for Power Quality Improvement

Background: Renewable energy sources offer sustainable solutions, but the conversion of DC energy into AC energy, commonly used in electrical devices necessitates inverters. Multilevel inverters have gained favor over conventional two-level inverters in high-power, mediumvoltage industrial and renewable energy applications due to their high switching frequency capabilities and ability to produce low-harmonic distortion voltage, ensuring superior power quality. Aims: This study focuses on addressing the adverse effects of harmonics in electrical systems and investigates methods to eliminate them in multilevel inverters. Methods: This study summarized current research works on traditional and advanced harmonic removal optimization strategies in multilevel inverters to highlight the limitations, objectives, THD%, and summary of existing works. Moreover, this study applies selective harmonic elimination techniques in 7-level and 15-level inverters using PSO and IPSO optimization algorithms to minimize THD and enhance inverter performance. Results: The study summarizes current research on harmonic removal strategies in multilevel inverters, revealing the prevalent use of MATLAB/Simulink in research endeavors. Various modulation and optimization techniques have been explored to achieve low THD in the output waveform, aligning with IEEE 519 standards for power system harmonic distortion. Furthermore, the comparative analysis part highlights increasing THD improvement with higher inverter levels. The 15-level inverter stands out, achieving 6.75% THD with PSO and 4.12% with improved PSO, meeting IEEE 519's THD limit. Conclusion: The study underscores the importance of ongoing research in this field to advance harmonic reduction strategies, making multilevel inverters even more attractive for a wide range of applications.

Total harmonic distortion analysis of inverter fed induction motor drive using neuro fuzzy type-1 and neuro fuzzy type-2 controllers

Introduction. When the working point of the indirect vector control is constant, the conventional speed and current controllers operate effectively. The operating point, however, is always shifting. In a closed-system situation, the inverter measured reference voltages show higher harmonics. As a result, the provided pulse is uneven and contains more harmonics, which enables the inverter to create an output voltage that is higher. Aim. A space vector modulation (SVM) technique is presented in this paper for type-2 neuro fuzzy systems. The inverter’s performance is compared to that of a neuro fuzzy type-1 system, a neuro fuzzy type-2 system, and classical SVM using MATLAB simulation and experimental validation. Methodology. It trains the input-output data pattern using a hybrid-learning algorithm that combines back-propagation and least squares techniques. Input and output data for the proposed technique include information on the rotation angle and change of rotation angle as input and output of produced duty ratios. A neuro fuzzy-controlled induction motor drive’s dynamic and steady-state performance is compared to that of the conventional SVM when using neuro fuzzy type-2 SVM the induction motor, performance metrics for current, torque, and speed are compared to those of neuro fuzzy type-1 and conventional SVM. Practical value. The performance of an induction motor created by simulation results are examined using the experimental validation of a dSPACE DS-1104. For various switching frequencies, the total harmonic distortion of line-line voltage using neuro fuzzy type-2, neuro fuzzy type-1, and conventional based SVMs are provided. The 3 hp induction motor in the lab is taken into consideration in the experimental validations.

Simulation-based probabilistic-harmonic load flow for the study of DERs integration in a low-voltage distribution network

<abstract><p>The integration of distributed energy resources (DERs) and, therefore, power electronic devices into distribution networks leads to harmonic distortion injection. However, studying harmonic distortion solely through deterministic approaches presents challenges due to the inherent random behavior of DERs. This study introduced a strategy that leverages PowerFactory's harmonic load flow tool. By combining it with Python co-simulation, probabilistic load flows can be developed. These load flows utilize current sources to represent harmonic distortion emitters with predefined harmonic spectra. The proposed strategy was implemented on a real network, where two different capacities of DERs were integrated at various locations within the network. The distributions for the total harmonic distortion of voltage ($ THD_{v} $) and the total harmonic distortion of current ($ THD_{i} $) were obtained 24 hours a day in nodes and lines of the network. The procedure allowed considering the uncertainty associated to the DERs integration in distribution networks in the study of harmonic distortion, which, speaking from a simulation approach, is scarce in the literature.</p></abstract>

An Improved Method for Reduction of Voltage Distortion in IPM EV Motors for a Better Flux Weakening Capability

An Improved Method for Reduction of Voltage Distortion in IPM EV Motors for a Better Flux Weakening Capability

Harmonics Distortion in Distribution Systems: A Review of Non–Linear Load Effects and Solutions

Alinear load shows current corresponding to the applied voltage, while a "non-linear" load has varying impedance with voltage, prompting non-sinusoidal current in any event when associated with sinusoidal voltage. Harmonic current in non-sinusoidal current blends in with power distribution framework impedance, causing voltage distortion affecting both the framework and associated loads. Expanded utilization of power electronics and time-changing nonlinear loads in industry prompts serious electrical cable contamination, corrupting power supply quality, and effectiveness, and causing overheating. Therefore, the incorporation of harmonic mitigation units is essential to minimize the effects of harmonic distortions and ensure the steady & reliable operation of the distribution network. As harmonic-creating loads rise, their effect becomes vital for framework changes. The paper frames harmonics, its effects and sources and various methods to mitigate it and talks about non-linear loads.

A Case Study: An Approach to Decrease Voltage Distortion and Enhance Field Weakening Capability in BMW i3 Traction Motor

A Case Study: An Approach to Decrease Voltage Distortion and Enhance Field Weakening Capability in BMW i3 Traction Motor

Simulations of electric multiple unit series 413/417 drives on the electrified tracks of "Serbian Railways"

In the paper, the Matlab-Simulink model of simulation of operation of the ŽS 413/417 series electric multiple unit (EMU) in traction and braking mode is exposed where changes are observed: stator currents of three-phase traction motors, traction electric motor speeds and electric multiple unit, electromagnetic torque on the rotor shaft of the traction electric motor and DC bus voltage. The model allowed review of the listed parameters for: different allowed values of contact network voltage and total voltage distortion at the place of connection of the electric multiple unit to the contact network, different mechanical loads of electric multiple unit and traction electric motor and different train speeds and rotation of traction electric motors. Appropriate conclusions were made through the analysis of the simulation results obtained.

Sideband Harmonic Suppression Analysis Based on Vector Diagrams for CHB Inverters Under Unbalanced Operation

Unexpected sideband harmonics of the cascaded H-bridge (CHB) inverters will appear in unbalanced conditions among cells and may result in harmonic pollution and even harmonic resonance. The linear controller to suppress the output voltage distortion is destined to be ineffective due to the non-linear characteristic of sideband harmonics. Focus on this problem, this article proposes a closed-loop harmonic suppression method by adjusting the phase-shift angles for the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> -cells CHB inverter. The harmonics suppression mechanism is revealed from a vector synthesis point of view. No complicated trigonometric function calculations and optimization algorithms are required. This method can achieve the suppression of the harmonic distortion around any multiplicative switching frequency. Phase-shift angles are adjusted continuously in real-time. The superior harmonic performance achieved by the proposed method is verified by the simulation and experiment results.

Minimizing Total Harmonic Distortion of 7-Level Packed U-Cell Multilevel Inverter Using Whale Optimization Algorithm

This paper presents an innovative study introducing a novel design for a single-phase, 7-level inverter. The design combines the modified pulse width modulation (MPWM) technique with the compact packed U-cell (PUC) topology. We evaluate this inverter's performance through comprehensive simulations in the MATLAB Simulink software. Multi-level inverter (MLI) technology is crucial for high-power, medium-voltage energy control. However, using numerous semiconductor switches in traditional MLI setups poses challenges at higher voltage levels, including increased size, costs, and losses. To address these issues, our study proposes a transformative approach, emphasizing reducing active switches within the multi-level inverter architecture. Consequently, we introduce an innovative 7-level PUC-MLI design. This configuration not only reduces harmonic distortion but also addresses cost concerns. Strategically manipulating semiconductor switch sequences significantly enhances the inverter's operational efficiency. A notable contribution is our inventive method to reduce total harmonic distortion (THD) in the inverter's output voltage, achieved through a whale optimization algorithm (WOA). Implementing this algorithm substantially lowers THD levels. Importantly, this approach's effectiveness extends to various inverter topologies and levels, offering a substantial THD reduction without additional expenses.

Разработка и исследование усовершенствованных алгоритмов ШИМ активных выпрямителей с целью улучшения качества электроэнергии во внутризаводских электрических сетях 6–35 кВ

Currently, application of frequency converters with active front end rectifiers (FC-AFE) has become a standard solution for powerful adjustable AC drives with frequent dynamic modes. The advantages of these converters include the possibility of recuperation of braking energy to the supply network, as well as the best electromagnetic compatibility of electromagnetic capability (EMC) with the supply network as stated by the manufacturers of converter technology. This statement is only partly true, since FC-AFE manufacturers do not consider possible resonant phenomena in the 6–35 kV intra-factory distribution network caused by the interaction of reactive elements of the power supply system. When significant harmonics of the FC-AFE current are superimposed on the resonant region, dangerous voltage distortions of 6–35 kV may occur. Traditional methods of providing electromagnetic capability of FC-AFE in this case may not have the desired effect. Therefore, it is relevant to develop alternative technical solutions to ensure an acceptable level of electromagnetic capability of FC-AFE. One such solution is the use of advanced PWM algorithms in the FC-AFE adapting to resonant phenomena in the 6–35 kV intra-factory network. The materials for the study are the oscillograms of the currents and voltages at the input of the FC-AFE obtained experimentally and using mathematical modeling. Experimental data have been obtained on operating equipment with FC-AFE and on a special laboratory setup. When developing improved PWM algorithm of AFE, a well-known mathematical apparatus is used. It describes the dependence of individual harmonics on the number of switching and switching angles. The results obtained show the effectiveness of improved PWM algorithms in terms of reducing the effect of FC-AFE on the supply network and improving the quality of electricity in intra-factory networks of 6–35 kV. The results of the study are implemented at a number of metallurgical enterprises, thanks to which it is possible to reduce voltage distortions of 6–35 kV and increase the stability of the operation of sensitive electrical receivers. The developed improved PWM algorithm of FC-AFE can significantly improve the quality of electricity in the in-house electrical networks of 6–35 kV without additional capital costs and installation of additional equipment. Based on the results obtained, it is recommended to use the developed PWM algorithms on the operating equipment with FC-AFE of industrial enterprises.

Optimization of the Voltage Total Harmonic Distortion in Multilevel Inverters by Using the Taguchi Method

A critical reduction in the total harmonic distortion in the output voltage of multilevel inverters can be obtained with an appropriate selection of the angles to switch the power semiconductors at low frequency. Among the methods used to obtain the required sequence of angles, it is possible to recognize both standard and optimized methods, like the Newton–Raphson method or the genetic algorithm, to mention a few. However, implementing the genetic algorithm implies using several configuration parameters, so it is difficult to know if the best option was chosen. This paper implements the Taguchi design of experiments, the Taguchi method, to obtain the appropriate switching angles for an multilevel inverter producing an output voltage of five and seven levels. Experimental results obtained from a laboratory prototype using the computed angles in the MATLAB GA solver demonstrate the superiority of the proposed method.

Unit vector template control strategy‐based harmonic mitigation and charging with three phase–three level–three switch Vienna rectifier for Level 3 electric vehicle charging applications

SummaryFast battery charging units act as non‐linear loads, which induce a more harmonic effect in the utility grid. Hence, maintaining the stable voltage, current ripple, and total harmonic distortions within the permissible IEEE std level during the charging time of grid to electric vehicle (G2V) has become an important task for researchers in the future. In order to mitigate power fluctuations during every charging cycle, it will enhance the battery life cycle in electric vehicles (EVs). Three phase–three level–three switch Vienna rectifier with fuzzy logic controller tuned PID controller is used here for AC/DC conversion with minimum switching loss. A fuzzy intelligent control strategy has been employed with the DC link voltage regulator in order to sustain the DC link voltage as constant and progress the voltage/current profile by injecting active power at the point of common coupling. Unit vector template (UVT)‐based control strategy is employed here to identify the fundamental components from the load side and also estimate the reference phase current. This scheme enhances the performance and reduces the mathematical system complexity to diminish the harmonics in the distribution grid. The adaptability and feasibility of this proposed control method have been verified by the MATLAB simulation tool. To validate the response of the Vienna Rectifier with UVT controller are simulated with different unbalanced load conditions and also verified with 30 kW laboratory prototype experimental results using dsPIC30F4011 controller and the switch is IRFP260 with power diode RHRG30120.

Detailed Controller Synthesis and Laboratory Verification of a Matching-Controlled Grid-Forming Inverter for Microgrid Applications

Grid-forming inverters are the essential components in the effort to integrate renewable energy resources into stand-alone power systems and microgrids. Performance of these inverters directly depends on their control parameters embodied in the controller. Even the most conscientiously designed controller will exhibit suboptimal performance upon implementation due to the presence of parasitic elements in the existing hardware. Hence, the controller has to be tuned and optimized. In the present article, the process of implementation, laboratory verification, and tuning of a matching-controlled grid-forming inverter is presented. In order to assess the efficiency of the grid-forming controller, its operation has been tested and analyzed in blackstart, steady state, and transient operation. For this purpose, a systematic sensitivity analysis has been conducted and the control parameters have been tuned in laboratory tests. The laboratory results verify proper operation of a 7 kW grid-forming inverter in all three test scenarios. After applying the proposed method on the tested grid-forming inverter in steady state operation, total harmonic distortion (THD) of the output voltage is less than 0.5% for its practical loading range (maximum THD is less than 1% in no-load condition). The system is able to blackstart and supply the loads. Finally, the studied grid-forming inverter is stable in the presence of severe step load changes and disturbances, i.e., voltage overshoot is managed well and compensated for with a low settling time using this approach.

Analysis of the Impact of Electric Vehicle Charging Station on Power Quality Issues

The sector of transport is being electrified because to rising worries about pollution and energy consumption, as well as technological breakthroughs in batteries. As a new technology, electric cars are still trying to find their niche. Its many benefits include less pollutant that contributes to climate change, less fuel use, and simplicity of use. Since chargers function as electric-electronic converters, power quality issues may arise while charging electric vehicles (EVs). More and more people are driving electric vehicles, which brings up concerns about how these vehicles may affect the electricity system and its quality. Power balancing and the effect of charging an electric car on voltage, current, and total harmonic distortion are the primary topics covered in this article. This research presents and analyses power quality concerns in EV charging stations based on monitoring data. Various chargers' harmonic current emissions are studied. The purpose of this study is to examine how the loads placed on the distribution network by electric vehicle charging stations affect reliability indices, power losses, voltage stability, and economic losses. This article uses MATLAB simulations to examine the effects of EVs on the electricity distribution network.

CONCEPTUAL MODEL OF A MICRONЕTWОRK WITH DISTRIBUTED ENERGY RESOURCES

Mіcrоnеtwоrk configurations are considered regarding the form of electricity transmission and distribution. The structures of connected units of dіstrіbutеd еnеrgy rеsоurcеs under different operating modes are described, in which special attention is paid to the primary control elements of dіstrіbutеd еnеrgy rеsоurcеs units for the instantaneous balance of active and reactive power, as well as to dispatch control architectures for long-term energy management. The characteristics of static and dynamic load are studied, the simulation of which is carried out by building physical models of typical loads. The parameters of the system of instantaneous balances of active and reactive power in mіcrоnеtwоrks determined by instantaneous load tracking and load distribution between blocks of distributed energy resources are obtained. The circuit of resistive active filtering of blocks of distributed energy resources for active compensation of distorted loads is given. The presented method effectively suppresses harmonic voltage distortions at the output of blocks of dіstrіbutеd еnеrgy rеsоurcеs. Ref. 10, fig. 2. Keywords: mіcrоnеtwоrk, еlеctrіcіty cоnvеrtеr, dіstrіbutеd еnеrgy rеsоurcе, lоаd dіstrіbutіоn, cоntrоl systеm.

Evaluation of three consumers' contribution to the current and voltage distortions at the point of common coupling

The article presents the method to evaluate share responsibility for the generation of harmonic currents between utility and consumer that are connected to the same point of common coupling (PCC). For these purposes, an indicator that evaluates the consumer's contribution to the distortion of current and voltage at the PCC is proposed, based on the previously carried out mathematical modeling of the power supply system (PSS) with two consumers. An evaluation of the distortion caused by three different non-linear loads on the consumers’ side is carried out in this study. The approbation of the proposed method was carried out on a laboratory bench, where various operation modes of linear and nonlinear loads were studied. Thus, the results proved that the proposed method could quantify the contribution of voltage and current distortion caused by three and more non-linear loads at the PCC of the consumer’s side. Besides, this proposed method can also be used to draw up recommendations for the mitigation of the harmonic currents compensation.

A Fast Dielectric Response Measurement Instrument With Dynamic Power Supply Tracking and Active Suppression of Temperature Fluctuations

This paper proposes a fast frequency domain dielectric spectroscopy (FDS) test scheme for diagnosing oil-paper insulation. The high-voltage output section introduces dynamic power supply tracking (DPST) and cascading techniques to generate high-voltage excitation signals. The DPST can increase the amplifier's voltage slew rate (SR) from 13 V per microsecond to 36.3 V per microsecond without crossover distortion. In the micro-current measurement section, the error active suppression structure of bias current and bias current under time-varying temperature conditions is proposed to improve the temperature stability of the measurement circuit. The fast testing technology shortens the test period by 65% in the low-frequency band by using the method of multi-frequency signal synthesis and partial cycle waveform fitting. The experimental results show that the total harmonic distortion and noise (THD+N) of the output voltage of the instrument are less than or equal to 0.078%. The voltage range is 780 Vpp. The standard deviation of current is less than 1.5%, and the standard deviation of tan δ is less than 1.7%, which verifies the stability of the designed instrument.

Simulation design and analysis 9-level H-bridge single phase stepdown cyclo inverter

This DC-to-AC voltage converter is designed for output frequency controlled by a 9-level cascade H-bridge cyclo inverter with pulse width adjustment. The aim of the study was to determine the pattern and format of the voltage, output frequency, and Total Harmonic Distortion index of a 9-level IGBT cyclo inverter. The method used is to build a unidirectional power converter design modeling into 9 alternating levels with cyclo converter-controlled frequency settings using the Simulink MATLAB tool. The cyclo converter section is constructed with two P and N converters in a parallel arrangement. The frequency and trigger pulse width of both converters control the output voltage and frequency format of the cyclo inverter. The test results show a series of ladder waves with an output frequency, of (1/2f, 1/3f, 1/4f, 1/5f, 1/6f, 1/7f, 1/8f, 1/9f, and 1/10f). The simulation results show that the nth input frequency divider waveform is characterized by the emergence of a number of step pulses of n positive half cycles and negative half cycles. The Total Harmonic Distortion Index gets bigger when the system circuit is designed at a low frequency. This modeling can be implemented into a prototype that is used for variable-speed DC motor drivers.