Multilevel inverter and total harmonic distortion (THD)

Top PDF Multilevel inverter and total harmonic distortion (THD):

Index Terms– Hybrid multilevel inverter, Space vector pulse width modulation (SVPWM), Total harmonic distortion (THD).

Index Terms– Hybrid multilevel inverter, Space vector pulse width modulation (SVPWM), Total harmonic distortion (THD).

Multilevel inverters have been widely used in medium and high voltage applications. Different modulation techniques have been proposed to control the multilevel inverter. This paper presents a switching strategy for cascaded multilevel inverters, based on space vector modulation. The SVPWM can be applied practically in hybrid multilevel inverters with different voltage steps; it can be applied to most multilevel topologies. This paper proposes a new algorithm for hybrid multilevel inverters with unequal voltage steps under the space vector pulse width modulation (SVPWM). The proposed algorithm offers an intuitive method for minimizing the total harmonic distortion (THD) of the output voltage of the inverter and uses simple arithmetic for determining the sector and does not require lookup tables. The proposed techniques lead to a significant reduction in THD. Finally, the algorithm was implemented on a Digital Signal Processor (DSP) and the scheme is explained for a seven level inverter, and experimental results are presented for a seven level inverter.
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Reduction of Total harmonic distortion in new Cascaded H-Bridge Multilevel Inverter topology using artificial neural network technique

Reduction of Total harmonic distortion in new Cascaded H-Bridge Multilevel Inverter topology using artificial neural network technique

Abstract - This paper deals with reduction of total harmonic distortion in new Cascaded H-bridge multilevel inverter topology with artificial neural network technique. This topology consists of lower blocking voltage on switches and it requires less number of dc voltage sources, power switches which results in decrease the complexity and total cost of the inverter. Moreover, a new algorithm is used to determine the magnitude of dc voltage sources for generation of all voltage levels. Artificial Neural Network (ANN) is trained by the back-propagation algorithm of the Mean Square Error (MSE) between the output and the desired value. The performance and functional accuracy of the proposed topology using ANN technique in generating all voltage levels for 31-level inverter are simulated using MATLAB simulink.
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Grid Connected Third Harmonic Injection PWM in a Multilevel Inverter Control with Proportional Resonant Controller

Grid Connected Third Harmonic Injection PWM in a Multilevel Inverter Control with Proportional Resonant Controller

According to the different types of major reference signals, PWM techniques can be divided into different categories Such as sine PWM, third harmonic injected PWM, sixty degree PWM, trapezoidal PWM etc. These techniques reduce the number of switching which reduces the switching loss [4]. Based on the total harmonic distortion (THD) analysis, third harmonic injected PWM (THPWM) is better among them [5]. THD is the measurement of harmonic distortion present in the output signal of the inverter. THD should be kept as low as possible because higher THD has unfavorable effect on power supply
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A Comparative Survey On Harmonic Optimization Of Multilevel Inverter

A Comparative Survey On Harmonic Optimization Of Multilevel Inverter

consisting of low cost, right performance and a few application which include PV panels and gas cells. Cascaded H-bridge MLI is one kind of these MLIs. Unlike the traditional inverter, the MLI's output voltage has a reduced THD with higher harmonic profile. Mathematical techniques for harmonic elimination are offered in some of the literatures however solving a non-linear transcendental equation set describing the SHE problem using these methods are not suitable for multi level inverters. A hybrid optimization set of rules to locate the most reliable switching angles in a Multilevel Inverter (MLI) is proposed in this paper. The switching angles are optimized to reduce low frequency harmonics. Total Harmonic Distortion (THD) method are implemented in order to lessen the switching losses. This paper summarizes different hybrid optimization techniques, which included the mechanisms of particle swarm optimization (PSO), genetic algorithm (GA), fuzzy logic controller and biography based algorithm which will optimize parameters. A comparative study of different algorithm has been studied.
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Reducing Total Harmonic Content of 9-Level Inverter by Use of Cuckoo Algorithm

Reducing Total Harmonic Content of 9-Level Inverter by Use of Cuckoo Algorithm

Abstract: In this paper, a novel procedure to find the firing angles of the multilevel inverters of supply voltage and, consequently, to decline the total harmonic distortion (THD), has been presented. In order to eliminate more harmonics in the multilevel inverters, its number of levels can be lessened or pulse width modulation waveform, in which more than one switching occur in each level, be used. Both cases complicate the non-algebraic equations and their solution cannot be performed by the conventional methods for the numerical solution of nonlinear equations such as Newton- Raphson method. In this paper, Cuckoo algorithm is used to compute the optimal firing angle of the pulse width modulation voltage waveform in the multilevel inverter. These angles should be calculated in such a way that the voltage amplitude of the fundamental frequency be generated while the total harmonic distortion of the output voltage be small. The simulation and theoretical results for the 9-levels inverter offer the high applicability of the proposed algorithm to identify the suitable firing angles for declining the low order harmonics and generate a waveform whose total harmonic distortion is very small and it is almost a sinusoidal waveform.
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A Study Of The Cascaded H-Bridge Multilevel Inverter Based On Supercapacitor For Harmonic Reduction

A Study Of The Cascaded H-Bridge Multilevel Inverter Based On Supercapacitor For Harmonic Reduction

Based on previous work that has been done, most researchers focus on the harmonic that occur on load and less concerned about the harmonics that occur at the power source. Power sources such as batteries, solar and other sources of DC supply which has a high Total Harmonic Distortion (THD) in term of voltage. Thus, this study is to change the power source from DC supply to supercapacitor and monitor it performance for harmonic reduction in output of cascaded H-Bridge multilevel inverter by using MATLAB/SIMULINK.
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Harmonic Elimination in Multilevel Inverter for Induction Motors using Modified Human Opinion Dynamics

Harmonic Elimination in Multilevel Inverter for Induction Motors using Modified Human Opinion Dynamics

This Section deals with the problem formulation of induction motor performance enhancement and the various challenges faced by the existing and proposed techniques. Evolutionary algorithms can be applied on various applications but it needs to be modified according to applications. Harmonic Elimination method provides an efficient method to remove lower order harmonics in various configurations of inverters. The selection of the type of inverter and the topology of the inverter plays an important role in the performance. This leads to a critical design requirement in terms of pulse wave design to be fed at the gate terminals of the various power electronics switches. The problem can also be visualized as an optimization problem with the pulse widths being the tuning parameters which needs to be optimized in terms of minimal Total Harmonic Distortion of the output. As mentioned above the pulse gate design can be visualized as an optimization problem which can be solved using various optimization algorithms. The research problem which we are targeting here is the design of multilevel inverters and their optimal selection of pulse width in order to reduce the total harmonics distortion to a minimal value, thereby improving the performance of the induction machine. Many models have been proposed for representing harmonic sources as well as linear components. Various network harmonic solution algorithms have also been published. In the following sections, we briefly summarize the well-accepted methods for harmonic modelling and simulations. Other chapters in this tutorial will expand upon these ideas and illustrate how to set up studies in typical situations. The most commonly used index for measuring the harmonic content of a waveform is the total harmonic distortion (THD). It is a measure of the effective value of a waveform and may be applied to either voltage or current. Total harmonic distortion is the contribution of all the harmonic frequency currents to the fundamental. Just as waveforms can be added to produce distorted waves, distorted waves may be decomposed into fundamental and harmonic components.
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Performance Analysis of Different Soft Techniques Applied in Multilevel Inverter for Harmonic Elimination

Performance Analysis of Different Soft Techniques Applied in Multilevel Inverter for Harmonic Elimination

As a result, continuous enhancements are desperately required on the potency front altogether industrial and client applications. Inverters play an important role in conversion of DC current obtained from these renewable sources of energy into AC current. once this process is done there'll be some loss in power due to the presence of harmonics and total harmonic distortion .So so as to achieve maximum power conversion and to prevent the device from getting damaged it is desirable to remove these harmonics and to attenuate the THD[7].

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Harmonic Minimization Of A Single Phase Cascaded H-Bridge Multilevel Inverter

Harmonic Minimization Of A Single Phase Cascaded H-Bridge Multilevel Inverter

This project represent the research of harmonic minimization of a single phase cascaded H-bridge multilevel inverter (CHB-MLI). Multilevel inverter is used to combine a desired single or three-phase voltage waveform and also to minimize the harmonics in the electrical system. This project use cascaded H-bridge (CHB) topology due to least number of components use, output voltage level are doubled, and easy to controllled compared with diode clamp (DC) and flying capacitor (FC) topology. This research use three and five levels cascaded H-bridge multilevel inverter based on Newton-Raphson technique controller by using MATLAB/SIMULINK in order to reduce the harmonic in electrical system. The value of total harmonic distortion (THD) has been obtained based on the simulation design of three and five levels CHB-MLI.
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Harmonic Reduction In Multilevel Inverter Using Particle Swarm Optimization

Harmonic Reduction In Multilevel Inverter Using Particle Swarm Optimization

(2.2) To minimize harmonic distortion and to achieve adjustable amplitude of the fundamental component, up to m-1 harmonic contents can be removed from the voltage waveform. In general, the most significant low-frequency harmonics are chosen for elimination by properly selecting angles among different level inverters [9] [10], and high-frequency harmonic components can be readily removed by using additional filter circuits. According to equation (2.12), to keep the number of eliminated harmonics at a constant level, all switching angles must be less than π / 2. However, if the switching angles do not satisfy the condition, this scheme no longer exists. As a result, this modulation strategy basically provides a narrow range of modulation index, which is its main disadvantage. For example, in a seven-level equally stepped waveform, its modulation index is only available from 0.5 to 1.05. At modulation indexes lower than 0.5, if this scheme is still applied, the allowable harmonic components to be eliminated will reduce from 2 to 1. The total harmonic distortion (THD) increases correspondingly.
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Reduction of Harmonic in a Multilevel Inverter Using Optimized Selective Harmonic Elimination Approach

Reduction of Harmonic in a Multilevel Inverter Using Optimized Selective Harmonic Elimination Approach

Genetic Algorithm (GA) has been proposed to solve the transcendental equations, [8]-[12]. Therefore in this proposed work by using an optimizing method like GA, an attempt is made to solve SHE equation whole range of modulation index and Total Harmonic Distortion (THD). In this proposed work single phase cascaded H-bridge five level inverter is chosen for analysis.

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Harmonic Reduction In Multilevel Inverter Based On GA Optimization

Harmonic Reduction In Multilevel Inverter Based On GA Optimization

Multilevel converters have drawn tremendous interest in recent years and have been studied for several high- voltage and high-power applications. Switching losses in these high-power high-voltage converters represent an issue and any switching transitions that can be eliminated without compromising the harmonic content of the final waveform is considered advantageous. The term multilevel starts with the introduction of the three-level converter. By increasing the number of levels in a given topology, the output voltages have more steps generation a staircase waveform, which approaches closely the desired sinusoidal waveform and also offers reduced harmonic distortion. One promising technology to interface battery packs in electric and hybrid electric vehicles are multilevel converters because of the possibility of high VA rating and low harmonic distortion without the use of a transformer. Harmonic Reduction-pulse-width modulation (HR-PWM) has been mainly developed for two- and three- level converters in order to achieve lower total harmonic distortion (THD) in the voltage output waveform. The main challenge associated with HR-PWM techniques is to obtain the analytical solution of the system for nonlinear transcendental equations that contain trigonometric terms which in turn provide multiple sets of solutions. Genetic algorithm has been recently introduced to optimize the sequence of the carrier waveform of the PWM as to minimize the THD and the distortion factor (DF) of output line voltage. An optimization technique assisted with a hybrid genetic algorithm was successfully applied to find the switching transitions (i.e. ., switching angles) of the HR- PWM ac/ac converter. More recently, a general genetic algorithm using Matlab GA optimization Toolbox was applied to solve the same problem of HR-PWM.
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Total Harmonic Distortion Minimization of Multilevel Converters Using Genetic Algorithms

Total Harmonic Distortion Minimization of Multilevel Converters Using Genetic Algorithms

This paper presents a genetic algorithm (GA) optimization technique to find the optimum switching angles of 11-level inverter with minimum number of dc sources and switches in comparison with the cascade multilevel inverter in order to minimize the total harmonic distortion (THD) of their output voltage waveform. Theoretical and simulation results for an 11-level converter show the efficiency of the proposed algorithm to determine the optimum angles in order to decrease the undesired harmonics and produce very high quality output voltage waveform.

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Reducing Total Harmonic Content of 7-Level Inverter by Use of Cuckoo Algorithm

Reducing Total Harmonic Content of 7-Level Inverter by Use of Cuckoo Algorithm

Abstract: In this paper, a novel procedure to find the firing angles of the multilevel inverters of supply voltage and, consequently, to decline the total harmonic distortion (THD), has been presented. In order to eliminate more harmonics in the multilevel inverters, its number of levels can be lessened or pulse width modulation waveform, in which more than one switching occur in each level, be used. Both cases complicate the non-algebraic equations and their solution cannot be performed by the conventional methods for the numerical solution of nonlinear equations such as Newton- Raphson method. In this paper, Cuckoo algorithm is used to compute the optimal firing angle of the pulse width modulation voltage waveform in the multilevel inverter. These angles should be calculated in such a way that the voltage amplitude of the fundamental frequency be generated while the total harmonic distortion of the output voltage be small. The simulation and theoretical results for the 7-levels inverter offer the high applicability of the proposed algorithm to identify the suitable firing angles for declining the low order harmonics and generate a waveform whose total harmonic distortion is very small and it is almost a sinusoidal waveform.
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Harmonic Optimization of Multilevel Inverter

Harmonic Optimization of Multilevel Inverter

Abstract:-In present work, optimization techniques genetic algorithm (GA) and particle swarm optimization (PSO) are used to compute switching angles for the cascaded multilevel inverter for selective harmonic elimination and the results are compared. Switching angles obtained from PSO produced better output with less harmonic content. Due to better performance PSO results are used further to obtain training set for Artificial Neural Network (ANN). Hence implementation of ANN for the elimination of low order harmonics is presented. Output voltage for nine level inverter is obtained for both single phase and three phase Cascaded Multilevel Inverter (CMLI). Switching angles are calculated through GA and PSO for various modulation indices and for minimum Total Harmonic Distortion (THD). Simulation results are presented using MATLAB and m file program. Through ANN real time implementation is possible with significantly reduced lower harmonics and improved performance.
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Comparison between Cascaded Multilevel inverter and reduced switch multilevel inverter

Comparison between Cascaded Multilevel inverter and reduced switch multilevel inverter

Abstract- This paper proposes a comparison between cascaded seven level inverter and nine level inverter using Phase opposition and disposition Pulse Width Modulation control scheme. The number of switches used in the cascaded seven and nine level inverter is identified and the Total Harmonic Distortion (THD) between them is compared. As the level gets increased the number of switches gets increased so the reduced switch topology is used with Pulse Width Modulation control scheme. The number of switches used in the reduced switch seven level and nine level inverter topology will be less when compared to the cascaded seven level and nine level inverter. The Total Harmonic Distortion (THD) between cascaded multilevel inverter and the reduced switch multilevel inverter is compared. The results are observed by MATLAB/SIMULINK software.
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Harmonic Distortion Elimination for STATCOM Application Using SHE PWM Cascaded Multilevel Inverter

Harmonic Distortion Elimination for STATCOM Application Using SHE PWM Cascaded Multilevel Inverter

©IJRASET 2013: All Rights are Reserved 105 There are three well-known disposition methods, specifically alternative phase disposition, in phase disposition (IPD), and phase opposite disposition (POD).Comparative evaluations of these methods based on total harmonic distortion (THD) for multilevel inverter topologies with number of levels, switching frequencies, and modulation indices have been reported in several articles. Zero sequence injected IPD CB-PWM, or else known as the switch frequency optimal PWM technique, with marginal THD enhancement is presented to further enhance the THD performance in lower modulation with extra switching instants. Despite its simplicity, the CB-PWM technique does not offer any direct manipulation over the harmonic contents and also exhibits high- switching losses due to high switching frequencies; making its service into high-power applications is a big problem where high- losses are intolerable. SVM, on the other hand, can be used to manipulate harmonics at low-modulation indices and maintain desired performance characteristics of multilevel inverter in low-switching frequencies. Though efforts have been made to extend the operation of multilevel inverters under SVM into the over modulation region, however, as the number of levels increases, the number of inverter’s states also severely increases resulting in difficulty to compute the duty cycles, selecting the proper switching states, and to determine the sector in which the reference vector lies in.
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An Effective Technique to reduce Total Harmonic Distortion in Distribution Network by using Neural Network

An Effective Technique to reduce Total Harmonic Distortion in Distribution Network by using Neural Network

Multilevel inverter have been attracting increasing interest recently due to the increased Quality Power to bring into being good quality results and for accurate evaluation, improving harmonic performance, In this project, an attempt has been made to improve the quality of power. A three level cascaded multi level inverter with identical dc supply is designed . Multilevel inverters continue to receive more and more attention because it avoid the use of extra clamping diodes and voltage balancing capacitors and thus it requires least number of components with compare to diode- clamped and flying capacitors type multilevel inverters topologies and thus it has modular structure with simple switching strategy and occupies less space and thus switching devices losses and stress is reduced, the output voltage amplitude is increased and improved overall harmonic profile can be achieved. high voltage operation capability, low switching losses, high efficiency. With its modularity and flexibility, the cascaded multilevel inverter shows superiority in high-power applications, because by connecting the H-bridge in series one can get required output voltage as well as power. In cascaded H-bridge multilevel inverter separate DC sources configuration is used to avoid short circuit of DC source. Here in this proposed project consists of three series H-bridge inverter units, each bridge module comprises of four Gate turn-offs Thyristor (GTO).
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Simulation with Experimental Measurement of Voltage Total Harmonic Distortion and Harmonic Frequency in Three-Phase Induction Motor fed from Inverter

Simulation with Experimental Measurement of Voltage Total Harmonic Distortion and Harmonic Frequency in Three-Phase Induction Motor fed from Inverter

Abstract- In general the Induction Motor is known to be a constant speed motor. In most of the industries the induction motor is mainly used for Drive Systems. But due to the advances in computer technology the speed of the induction motor can be controlled under certain conditions. There are many ways to control the speed of the Induction Motor for variable speed applications. The basic method is 2-level inverter controlled by microcontroller using space vector modulation. In this method the output of the inverter may not be exactly sinusoidal and hence at the star point of the Induction Motor winding, causing a Voltage Harmonic Distortion in the output of the inverter. To minimize the voltage harmonic distortion a multilevel inverter can be used. In addition, the harmonic frequencies will not produce usable torque but causes heating the Induction motor windings, which are harmful to the insulation. In this paper two level and three level inverter fed induction motor driven at various frequencies are reported. Simulation, experimentation and the measurement of voltage total harmonic distortion have also been reported. In the experiment the Arduino microcontroller, Line Impedance Stabilization Network, opto- isolator, Hall Effect sensor, H-bridge inverter and other necessary electronic circuits are used. The measurements are recorded using Agilent make Mixed signal Oscilloscope. The Fast Fourier transform has been carried out for the experimental result, using signal analysis software. Simulation has been implemented using the MATLAB/Simulink. The results of simulation and experimentation are compared and tabulated.
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Harmonic Minimization in Seven Level Cascaded Multilevel Inverter Using Selective Harmonic Elimination PWM Techniques

Harmonic Minimization in Seven Level Cascaded Multilevel Inverter Using Selective Harmonic Elimination PWM Techniques

This paper concentrates on enhancing the productivity of the multilevel in- verter and nature of yield voltage waveform. Seven level lessened switches to- pology has been actualized with just seven switches. Essential Switching plan and Selective Harmonics Elimination were executed to diminish the Total Harmonics Distortion (THD) esteem. Selective Harmonics Elimination Stepped Waveform (SHESW) strategy is executed to dispense with the lower order harmonics. Fundamental switching plan is utilized to control the switches in the inverter. The proposed topology is reasonable for any number of levels. The harmonic lessening is accomplished by selecting fitting switching angles. It indicates would like to decrease starting expense and unpredictability con- sequently it is able for modern applications. In this paper, third and fifth level harmonics have been disposed of. Simulation work is done utilizing the MATLAB/Simulink programming results have been displayed to accept the hypothesis.
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