Total Harmonic Distortion Level Research Articles

Simultaneous allocation of soft open points and tie switches in harmonic polluted distribution networks

The growing power quality issues stemming from the higher presence of converter-based appliances in the distribution network increases the harmonic risks. Given the importance of tackling these issues to deliver high-quality power to customers, this investigation provides a promising approach focused on effectively designating soft open points (SOPs) and tie switches in the distribution networks. The objectives of this investigation include the reduction of total harmonic distortion (THD), power loss per various harmonic frequencies and the number of SOPs. To evaluate the performance of the proposed approach, the study is carried out on two well-known networks, 33-bus, and 69-bus. Through these analyses, it was shown how effectively THD, power loss, and voltage profiles are improved when SOPs and tie switches are allocated together. The outcomes of thorough analyses provide credence to the assertion that the suggested approach is very promising for mitigating power quality issues by handling uncertainties in loads by Monte Carlo Simulation (MCS). In more detail, the obtained solutions assure that the suggested method has superior power quality across the networks by maintaining the THD levels within the standard margins. Additionally, the developed model offers advantages including reduced power loss and enhanced voltage profiles, which increase the overall network efficiency, while reducing the total investment cost by reducing the number of SOPs and power loss in power distribution networks.

Mitigation of Harmonics Due to Electric Vehicle Charging

The increasing adoption of electric vehicles (EVs) has led to an increase in demand for charging infrastructure. However, EV charging can introduce harmonic distortion into the electrical distribution network, causing power losses, reduced efficiency, and equipment damage. This project developed an EV charging system with harmonic reduction to ensure a stable and efficient charging process. The research methodology allowed the team to develop an EV charging system with harmonic reduction that was effective in reducing the total harmonic distortion (THD) level from 56.3% to 1%. The system was also found to be stable and efficient during charging. The findings of this project have the potential to make a significant contribution to the development of EV charging infrastructure. The proposed system can help to mitigate the negative impacts of EV charging on the electrical distribution network, while also ensuring a stable and efficient charging process.

Improve the voltage profile of the grid-integrated induction motor with a fuzzy-based voltage source converter

This article suggests installing a series compensator on grid-connected induction motors that allows for the ride-through of unbalanced voltage sag. Fuzzy logic controls the motor voltages in a standard three-phase voltage source inverter or voltage source inverter (VSI). An open-ended three-phase machine and the grid form a series connection for the VSI. The proposed system is well suited for uses where frequency variation is unnecessary, such as with large pumps or fans. There is no requirement for a direct current (DC) source or injection transformer when conducting an electric mutual coupling The severity of the sag in the grid voltage that will prevent EMC from shutting down is proportional to the load on the motors. An increase in the voltage of the DC link may be necessary if the voltage is not balanced. A 1.5 hp four-pole induction motor was used alongside grid voltage disturbances to test the proposed compensator's ride-through capability. Grid's current analysis demonstrates that the proposed system does not require the addition of a passive filter to achieve low levels of total harmonic distortion (THD). Additionally, the control strategy, component ratings, and analysis of the converter's output voltage operating principle and pulse width modulation technique are covered. The system's viability is shown via simulation and experimental results.

Comparative Analysis of Bipolar and Unipolar SPWM Techniques in PIC-Based Pure Sine Wave Single-Phase Inverters

This paper provides a comparative analysis of bipolar versus unipolar Sinusoidal Pulse Width Modulation (SPWM) in DC-AC inverters, focusing on Total Harmonic Distortion (THD) across modulation indices and the latter’s effects on the R-L loads. Using the PIC18F2431 microcontroller for its efficiency, a single-phase inverter accomplished to deliver a high-fidelity sine wave. This study discovered that while both SPWM methods reduce harmonics, the unipolar approach yields more uniform THD reduction and superior performance, particularly noticeable in RL load conditions, where minimal harmonic distortion is crucial. The bipolar inverter, despite a higher initial THD, shows a considerable improvement at higher indices, significantly enhanced by an LC low-pass filter. This filter is a key component in achieving sub-1% THD levels at full modulation, ensuring optimal sine wave quality. The findings highlight the operational differences between the SPWM techniques and the importance of the LC filters in ameliorating the inverter output for various power applications.

The Implementation of Space Vector PWM in 36-Pulse D-STATCOM for Power Quality Improvement

Introduction: This paper addresses the ongoing challenge of harmonics reduction in power systems, particularly focusing on Flexible AC Transmission Systems (FACTS) devices. Instead of employing a conventional multilevel converter, an alternative configuration is proposed: a 36-pulse gate turn-off thyristor-based converter (GTO-VSC). This converter comprises three 12-pulse Voltage Source Converters (VSCs) as fundamental units, operating collectively on the frequency mode of GTO switching control within a Distribution Static Synchronous Compensator (D-STATCOM). The D-STATCOM dynamically compensates reactive power in the system. The 36-pulse configuration results in AC output voltage waveforms containing harmonics such as the 35th, 37th, 71st, 73rd, etc., leading to higher total harmonic distortion (THD) levels. background: Reduced number of switches in flexible AC transmission. Method: In response, the paper presents a new model featuring a 3-level, 36-pulse, 25kV, ±3MVAr STATCOM configured with 12-pulse GTO-VSCs. This model incorporates PWM gate switching and employs a PI-control methodology to optimize harmonics in simulation, specifically targeting harmonics at the 35th, 37th, 71st, 73rd, etc., orders using Sim Power Systems toolbox in Math Works software. Result: The compensator's operational performance is controlled through switching angle optimization, which minimizes harmonics, regulates voltage, and manages reactive power in the electrical transmission system. Conclusion: The simulation results demonstrate that the proposed model is acceptable for enhancing the flexibility and performance of the FACTS device in mitigating harmonics in power systems.

Robust adaptive backstepping control of H‐bridge inverter based on type‐2 fuzzy optimization of parameters

AbstractA type‐2 fuzzy logic‐based adaptive backstepping control (T2FABSC) approach is designed for an H‐bridge inverter. This inverter has an LC filter to decrease the level of total harmonic distortion (THD) that can affect the efficiency of the system. Reduction of THD and stability insurance of the filter are challenging trade‐offs, tackled here by a controller design. The performance, however, is not suitable for actual applications under a wider range of disturbances, and the parameters need to be adjusted once more for more dependable operations. Backstepping control is given a Lyapunov definition‐based adaptive mechanism that can improve this scheme's stability and robustness in the face of numerous disturbances. Additionally, the system is viewed as a “Black box” without the need for a precise mathematical model, which might lead to a lighter computing burden and simpler implementation. Moreover, a fuzzy type‐2 structure is adopted that can optimize the gains of the adaptive Backstepping controller (ABSC) in challenging conditions. The antlion optimization algorithm is employed to optimize the parameters of the membership functions in the fuzzy system, hence improving the performance of the controller. In addition, compared with different optimization algorithms, it can more quickly and accurately locate the best solutions. Finally, the findings of both the simulations and the experimental outputs are examined, proving the T2FABSC's significant robustness and faster dynamics in a variety of challenging circumstances.

Evaluation of LVRT capability and stability analysis of VSC based advanced control approach for grid connected PV system under grid fault conditions

Short circuit faults are a prevalent issue in power systems, causing disruptions to the grid's normal operation. Dynamic behaviours of the conventional power systems during short circuit faults have been extensively studied and understood. The bulk of ongoing research and development are focusing on the dynamic performance of grid-connected renewable energy systems under these fault conditions, due to changes in the grid code and a decrease in system inertia. The development of effective control strategies to enhance the system's reliability during fault conditions is of paramount importance. In this paper, a two-stages grid-connected photovoltaic system (GCPV) having a rated power of 2 MW was created in the MATLAB/Simulink environment. The dynamic behaviour of the presented system was evaluated in two scenarios: steady state conditions and short circuit faults. A line-to-ground short circuit fault was created at the grid side, and its effect on the PV system's operation was observed. An advanced control system was designed to maintain stability during fault conditions. The results demonstrated the efficiency of the designated control system in minimizing the effects of short circuit faults on the GCPV system's function, and restoring the system promptly after the fault was cleared. Furthermore, considering modifications in grid regulations, the low voltage ride through (LVRT) capability of the designed system was analysed and validated according to the UK standards. The Total Harmonic Distortion (THD) level at the common coupling point was also analysed for voltage and current, remaining below the acceptable level of 5% as specified in the IEEE Std. 519.

Comparative Study of THD Characteristics in Different Cascaded H-Bridge Configurations for Multilevel Multicarrier Modulation

This paper presents a comprehensive comparative study investigating the Total Harmonic Distortion (THD) characteristics of various Cascaded H-Bridge (CHB) configurations utilized in Multilevel Multicarrier Modulation (MMCM) systems. The research examines different CHB topologies, focusing on their impact on THD performance in MMCM applications. Through theoretical analysis and simulation, this study evaluates THD levels under varying operating conditions, including different modulation schemes and switching strategies. A discussion on main topologies of multilevel inverter namely H-bridge, NCP(neutral point clamped),NCP- H and flying capacitor is carried out utilizing carrier based PWM methods. Comparison is done on basis of harmonic component, THD and nu of component used by 3, 5 and7 level cascaded H-bridge topology respectively. To support the result a detailed study is carried out using MATLAB Simulink software. Keywords- Multilevel inverter, PWM, THD, NCP, NCP-H.

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.

SIMULATION MODEL OF AN ADARTIVE DIGITAL FILTER BASED ON THE LEAST SQUARES METHOD

In accordance with contemporary requirements in the fields of mobile and embedded telecommunications and electronics, there is a growing need for faster, smaller, and energy-efficient digital electronic devices (DEDs). These devices include microcontrollers, digital signal processors, and programmable logic integrated circuits (FPGAs).
 Utilizing DEDs involves the hardware execution of advanced digital signal processing (DSP) algorithms tailored to the specific architecture of the electronic device. To expedite the design process when directly implementing DSP algorithms in hardware, simulation models are generated to facilitate optimizing the design during the creation of the programming component for FPGAs.
 The paper discusses the outcomes of an investigation into an adaptive filter (AF) model that relies on the recursive least squares method (RLS). During the simulation, an analysis of the time and frequency parameters of the AF model was conducted. It was determined that the quality of the filtering process reaches a plateau at the 28th order, and further increasing the AF order does not lead to a significant improvement in signal filtering. Instead, it results in an increased demand for hardware resources. Furthermore, during the verification of the proposed simulation model, an AF-based noise reduction system was simulated. The total harmonic distortion (THD) level for the built-in AF unit was found to be 1.05 % that serves as confirmation of the effectiveness of the developed AF unit.
 Therefore, through this investigation, the most suitable order for the AF has been identified. This choice will enable a more effective utilization of FPGA resources when implementing the AF in hardware. The study results validate the accuracy and effectiveness of the hardware-centric simulation model developed, while also demonstrating the hardware-oriented architecture of the adaptive RLS filter for its forthcoming implementation on FPGA.

To Study Impact Of Electric Vehicle Charging On Power Quality On Various Loads

Electric Vehicles (EVs) are a clean energy alternative to gas and energy powered vehicles. They form a crucial part of the present and future automotive. Electric vehicles being non-linear loads could affect the power quality of the grid. In this paper, we present a view of the fluctuations in power factor and Total Harmonic Distortion (THD) levels when varying number of electric vehicles (two wheeler and four wheeler) are connected to the power system .The system was simulated and studied in Simulink. Here, a captive power plant that is supplying power under base load and peak load conditions is considered.

Unified variable regularization factor based static compensator for power quality enhancement in distribution grid

A unified variable regularization factor based strategy for harmonic filtering at the supply side of the distribution system is presented in this paper. For this purpose, a three-phase distribution grid along with a distribution static compensator and a rectifier based nonlinear load is considered. A combined regularization affine projection sign algorithm-based control technique is used to calculate the weight values that denote the active power and reactive power segments of the load current. The proposed algorithm contains a variable mixing factor of two adaptive filters with different regularization parameters. The variable mixing factor enhances the tracking performance of the algorithm and hence it offers quick convergence and less steady-state error when compared with other affine projection-based filtering schemes. The control algorithm is evaluated under varying load patterns to derive its robustness and stability. Empirical assessment is carried out through real time simulation analysis aided by dSPACE-1202 controller. The performance of the applied control technique is found good-enough in mitigating the supply side harmonics and the total harmonic distortion levels rendered by the experimentation are in-line with the IEEE-519 standard.

A Comparative Study of Smart THD-Based Fault Protection Techniques for Distribution Networks

The integration of Distributed Generators (DGs) into distribution systems (DSs) leads to more reliable and efficient power delivery for customers. However, the possibility of bi-directional power flow creates new technical problems for protection schemes. This poses a threat to conventional strategies because the relay settings have to be adjusted depending on the network topology and operational mode. As a solution, it is important to develop novel fault protection techniques to ensure reliable protection and avoid unnecessary tripping. In this regard, Total Harmonic Distortion (THD) can be used as a key parameter for evaluating the grid’s waveform quality during fault events. This paper presents a comparison between two DS protection strategies that employ THD levels, estimated amplitude voltages, and zero-sequence components as instantaneous indicators during the faults that function as a kind of fault sensor to detect, identify, and isolate faults. The first method uses a Multiple Second Order Generalized Integrator (MSOGI) to obtain the estimated variables, whereas the second method uses a single SOGI for the same purpose (SOGI-THD). Both methods rely on communication lines between protective devices (PDs) to facilitate coordinated protection. The effectiveness of these methods is assessed by using simulations in MATLAB/Simulink considering various factors such as different types of faults and DG penetrations, different fault resistances and fault locations in the proposed network. Moreover, the performance of these methods is compared with conventional overcurrent and differential protections. The results show that the SOGI-THD method is highly effective in detecting and isolating faults with a time interval of 6–8.5 ms using only three SOGIs while requiring only 447 processor cycles for execution. In comparison to other protection methods, the SOGI-THD method exhibits a faster response time and a lower computational burden. Furthermore, the SOGI-THD method is robust to harmonic distortion, as it considers pre-existing harmonic content before the fault and avoids interference with the fault detection process.

Neutral-point-clamped inverter based synchronous reluctance motor drive for solar pump application

PurposeIndustrial drives require appropriate control systems for reliable and efficient performance. With synchronous reluctance machines (SynRMs) slowly replacing the most commonly used induction, switched reluctance and permanent magnet machines, it is essential that the drive and its control be properly selected for enhanced performance. But the major drawback of synchronous reluctance motor is the presence of high torque ripple as its design is characterized by large number of variables. The solutions to reduce torque ripple include design modifications, choice of proper power electronic inverter and PWM strategy. But little has been explored about the power electronic inverters suited for synchronous reluctance motor drive to minimize torque ripple inherently by obtaining a more sinusoidal voltage. The purpose of this paper is to elaborate on the potential multilevel inverter topologies applicable to SynRM drives used in solar pumping applications.Design/methodology/approachThe most significant field-oriented control using maximum torque per ampere algorithm for maximizing the torque production is used for the control of SynRM. Simulation results carried out using Matlab/Simulink are presented to justify the choice of inverter and its control technique for SynRM.FindingsThe five-level inverter drive gives lesser core or iron losses in the SynRMin comparison to the three- and two-level inverters due to lower Id current ripple. The five-level inverter reduces the torque ripple of the SynRM significantly in comparison to the three- and two-level inverter fed SynRM drives. The phase disposition-PWM control method used for the inverter shows the least total harmonic distortion (THD) levels in output voltage compared with the other level shifted PWM techniques.Originality/valueAmong the available topologies, a fitting topology is proposed for use for the SynRM drive to have minimal THD, minimal current and torque ripple. Additionally, this paper presents various modulation techniques available for the selected drive system and reports on a suitable technique based on minimal THD of output voltage and hence minimal torque ripple.

Design, implementation and performance evaluation of multi-function boost converter

This paper introduces a single-phase multi-function converter (MFC) circuit that can perform the power electronics functions of a DC–DC, a DC–AC, an AC–AC, and an AC–DC boost converter. The power circuit of the proposed converter contains only four bi-directional switches, which is sufficient side by side with a switched logic-based control system to execute converter functions. The proposed converter can implement the boosting converter function, which is a drawback of the conventional single-phase matrix converter, which is limited to performing the buck converter functions. The mathematical analysis of each converter function is presented. A state space averaging technique is employed to obtain the time-invariant state space model for a better understanding of the converter characteristics. The frequency response approach is used to demonstrate the effect of circuit parameters on converter stability using the time-invariant state-space model. Moreover, the performance analysis of the system is checked through the building of a simulation model of the proposed converter via MATLAB/Simulink and MATLAB/Simscape toolbox integration. Additionally, the actual performance of the proposed converter is verified through a laboratory prototype experimental study. The experimental results confirm those obtained by computer simulation, clearly demonstrating the successful operation of the proposed circuit as a multi-function converter with acceptable levels of total harmonic distortion (THD).

A Fifteen Levels Inverter with A Lower Number of Devices and Higher Performance

Multi-level inverters, as a result of the significant contributions they have made to the fields of high voltage and renewable energy applications, MLI has earned a prestigious place in the field of industrial electronics applications. The use of MLI makes it possible to generate an alternating voltage from a DC voltage or from voltages that are continuously applied thanks to this capability. The quality of the produced wave depends on minimizing the level of total harmonic distortion (THD) in the ensuing output voltage. Increasing the total number of levels is required in order to bring down the THD. The bigger the number of layers, the lower the THD. On the other hand, this necessitates an increase in the number of power switches that are utilized, in addition to an increase in the number of DC sources for certain types. A greater number of levels are achieved in this work with a reduced number of switches, and the DC source necessitates the use of specialized control over the switches as well as the grading of the DC source values. In order to demonstrate that the suggested converter achieves the needed outcomes, the MATLAB simulator is utilized.

A Fifteen Levels Inverter with A Lower Number of Devices and Higher Performance

Multi-level inverters, as a result of the significant contributions they have made to the fields of high voltage and renewable energy applications, MLI has earned a prestigious place in the field of industrial electronics applications. The use of MLI makes it possible to generate an alternating voltage from a DC voltage or from voltages that are continuously applied thanks to this capability. The quality of the produced wave depends on minimizing the level of total harmonic distortion (THD) in the ensuing output voltage. Increasing the total number of levels is required in order to bring down the THD. The bigger the number of layers, the lower the THD. On the other hand, this necessitates an increase in the number of power switches that are utilized, in addition to an increase in the number of DC sources for certain types. A greater number of levels are achieved in this work with a reduced number of switches, and the DC source necessitates the use of specialized control over the switches as well as the grading of the DC source values. In order to demonstrate that the suggested converter achieves the needed outcomes, the MATLAB simulator is utilized.

Analysis of total harmonic distortion in single-phase single-stage grid-connected photovoltaic system

<p>This study presents the power quality issue mainly focus the effect of total harmonic distortion (THD) on a grid-connected PV system. Firstly, a grid-connected PV system with a single-phase single-stage has been developed to monitor the output values of voltage and current and also its harmonic distortion behaviours. Maximum power point tracking (MPPT) was implemented since it is proven as the first step for THD reduction because MPPT will extract maximum output power, voltage, and current of the PV system without fluctuation which leads to a low THD level. Furthermore, the employment of a good filter also reduces the THD level in a PV system. Thus, this study will focus on the THD analysis to resolve the power quality problems in the grid-connected PV system. The result shows that the THD value for current, <em>I<sub>THD</sub></em> analysis is more significant than the THD value for voltage, <em>V<sub>THD</sub></em> analysis in the case of grid-connected PV systems operating under different solar irradiances. In a conclusion, the increase in solar irradiance will increase the rated values of generated power and current thus, increasing the performance of THD values.</p>

Implementation of an anti-windup control under partial shading for a photovoltaic grid interfaced system

Owing to the growing technological advancements in control startgies for addressing the various power quality issues in distributed generation systems, an anti-windup control strategy for reducing the impact of partial shading is proposed in this present work. The performance of a Solar Photovoltaic (SPV) grid interfaced system is evaluated during the presence of a single phase to ground fault. Majorly, the SPV array is also operated under partial shading conditions by changing levels of solar radiation and ambient temperature conditions. The performance of a Proportional Integral (PI) anti-windup controller is justified by demonstrating the flow of active-reactive power with minimum levels of harmonics. This controller has ably demonstrates its effectiveness in mitigating the impact of partial shading. The validated data sheet SPR-305-WHT is used to validate the obtained results. Total Harmonic Distortion (THD) levels are estimated at various coipling points. It is revelaed that the THD levels of grid current at Point of Common Coupling (PCC) are less than 5%. According to IEEE-519 standard, the level of harmonics must be less than 5%. Overall, the proposed scheme can be helpful for future research engineers and professionals working on improving various power quality aspects.

Comparative Exploration of 19-level and 21-level Cascaded H- Bridge MLI with Cross H-Bridge MLI

Present days renewable energy sources based grids are developing which needs inverters to convert power from DC to AC. 2-level inverters were used for this purpose to overcome the drawbacks of 2-level inverters multilevel inverters are developed. Because of the combination of numerous devices in a series structure, multilevel inverters provide outstanding solutions to high voltage, high power applications. With the use of suitable simulations and mathematical analysis, this paper compares the performance of 19 and 21-level cascaded H-Bridges with cross H-Bridge MLI. Total Harmonic Distortion levels, switching device count, and inverter output voltage and current are all compared. The primary issues brought up in this study are limitations of a number of switching devices that can support high voltage in the inverter. The benefit of this research is that it identifies the right inverter that can be utilised for real-time applications by taking the variables into account. The count of switching devices, output voltage, current, and harmonic distortion, among other factors. The Matlab/Simulink Platform is used to validate the analysis.