Multi Level Inverters Research Papers (original) (raw)

Estimation of optimum switching angles for
multilevel converters so as to produce the required fundamental
voltage while at the same time eliminate specified lower order
harmonics through Artificial Neural Networks (ANNs) is
presented. The proposed technique uses the best performance
solutions (lowest THD solutions) as the training data set for
proposed ANN system. This technique can be applied to
multilevel inverters with any number of levels. As an example, in
this paper estimation results of optimum switching angles are
given for seven levels inverter to eliminate the 5th and 7th
harmonics. After training the proposed ANN system, a large and
memory-demanding look-up table replaced with trained neural
network to generate the optimum switching angles with lowest
THD for a given modulation index. The simulation results are
presented in PSCAD/EMTDC software package to validate the
accuracy of estimation results by proposed ANN system.

- by
- •
- Artificial Neural Networks, Multilevel Inverter, Multi Level Inverters

Inverter is an important topology in modern power electronic system which provides a solution to convert the average power flow from DC power to AC power. Inverter employs different soft switching techniques to solve the problems faced in industrial applications such as harmonic reduction , stress reduction and switching power loss minimization. This paper presents the detailed study and comparative analysis of inverter and multilevel inverter.

- by Arsalan Usmani
- •
- Power Electronics, Power Quality, Matlab, Matlab/Simulink

—This paper presents two types of multilevel inverters, known as symmetrical and asymmetrical multilevel inverter. Both types are very effective and efficient for improving the quality of the inverter output voltage. Firstly, we describe briefly the structural parts of the inverter then switching strategy and operational principles of the proposed inverter are explained and operational topologies are given. The proposed topology reduces the number of switches, losses, installation area and converter cost. Finally, the simulation results are provided to validate the proposed theory.

- by sai ram
- •
- Multi Level Inverters

The photovoltaic panel not only generates low DC voltage but also DC voltage which varies with time and environmental condition. Therefore design of electrical energy system with constant output voltage is a big challenge to designer. This project deals with the development of electrical energy system which consists of Z-source based high step up chopper. The chopper is basically based on coupled inductor which provides high voltage gain and physical isolation between input and output with small turn ratio. It also provides a low voltage stress on active components and small conduction losses due to low duty cycle. Due to the usage of a single switch, the control circuitry is less complex. The proposed chopper recycles the energy of leakage inductance hence enhancing system efficiency. This report consists of mathematical modelling and designing of proposed chopper circuit. The MATLAB simulation of proposed chopper circuit is to convert 25 volts dc to 400 volts dc with 300 watts power. The simulation results validate the theoretical results. The H-Bridge inverter circuit is used at the end of proposed chopper for converting DC voltage into AC voltage.

Multi-level inverters (MLIs) are gaining popularity due to their inherent advantages like better harmonic distortion, ability of producing higher magnitudes of AC voltages. As these converters uses many cascaded connection of many small units the switches used in devices are subjected to less voltage stresses. H-bridge based multilevel inverter can increase the number of output voltage levels by adding switch components and DC input voltage sources. If it employs seven switches and three DC sources, the number of output voltage levels becomes seven. Although its THD characteristics are improved, it needs output filter to meet general output voltage THD requirement, i.e., 5 % below. By adding PWM switching schemes to the operation of the prior H-bridge switches, it can synthesize more sinusoidal waveform. By this simple alteration in the switching scheme, it can improve the output voltage THD requirement. To verify the high performance of the proposed switching scheme, Unipolar, Bipolar, Third harmonic based Pulse width modulation schemes are considered for analysis and computer-aided simulations are conducted using MATLAB.

- by International Journal of Research in Science & Technology (IJRST) and +1
- •
- Multi Level Inverters

In recent years, multilevel inverters (MLIs) have emerged to be the most empowered power transformation technology for numerous operations such as renewable energy resources (RERs), flexible AC transmission systems (FACTS), electric motor drives, etc. MLI has gained popularity in medium- to high-power operations because of numerous merits such as minimum harmonic contents,
less dissipation of power from power electronic switches, and less electromagnetic interference (EMI) at the receiving end. The MLI possesses many essential advantages in comparison to a conventional two-level inverter, such as voltage profile enhancement, increased efficiency of the overall system,
the capability of high-quality output generation with the reduced switching frequency, decreased total harmonic distortions (THD) without reducing the power of the inverter and use of very low ratings of the device. Although classical MLIs find their use in various vital key areas, newer MLI configurations have an expanding concern to the limited count of power electronic devices, gate
drivers, and isolated DC sources. In this review article, an attempt has been made to focus on various aspects of MLIs such as different configurations, modulation techniques, the concept of new reduced switch count MLI topologies, applications regarding interface with renewable energy, motor drives, and FACTS controller. Further, deep insights for future prospective towards hassle-free addition of
MLI technology towards more enhanced application for various fields of the power system have also been discussed. This article is believed to be extremely helpful for academics, researchers, and industrialists working in the direction of MLI technology.

- by Mohit Bajaj
- •
- Power Electronics, Multi Level Inverters

This paper investigates and analyses the phase disposition pulse width modulation (PDPWM) based Reduced Switch Reverse Voltage (RSRV) multi level inverter. This inverter has been designed with lesser number of components. Enhancement of output power quality using PDPWM is discussed with respect to the amplitude and frequency modulation index values. This PDPWM based 9-level inverter with reduced components and odd valued frequency modulation index value, produces better harmonic spectrum. All the lower order harmonics are well within the limit defined by the IEEE-519 standard. The simulation model of PDPWM based asymmetrical 9-level inverter with reduced number of components is built to validate its operation and the results are presented.

This dissertation gives the investigation in
the area of AC/AC power conversion and
DC/DC with solid state transformer. The
proposed single phase solid state
transformer with bidirectional flow
capability may find application in compact
isolated PWM AC drives. This topology
along with the proposed control has the
following advantages. A)input power factor
correction b) Common mode voltage
suppression at the load end , c) high quality
output voltage waveform (compared to the
conventional space vector PWM) and
d)minimizing output voltage losses, And
lossless commutation for soft switching .

The application and research interest over modular multilevel converters (MMCs) has grown significantly over the last couple of years. The term MMC has been expanded to include all converters built on the series connection of sub-modules (SMs)
as a basic building block forming converter arms and phase-legs. A review of the current literature reveals an abundance of SM configurations ranging from SMs derived from the well-knownmultilevel converter topologies to novel configurations targeted to niche MMC applications. This paper provides a comprehensive review of the current SM configuration state and a comparative evaluation based on complexity of configuration, voltage balancing and component count. It also provides an evaluation of switching and conduction losses for the devices within each SM, identifying those SMs that are more suitable to general MMC applications.

For application of PV systems, a major deterrent factor in their use is high initial investment. A focus has therefore been placed on new, cheap and innovative inverter solutions. As a result of this, a single stage inverter topology and a new configuration are proposed. In two stage circuit, the first stage takes care of MPPT and boosting the PV voltage while second stage inverts the first stage output into the required AC form. A two stage configuration has drawbacks such as high part count, lower efficiency, lower reliability, high cost and large size. These drawbacks are overcome by the circuit proposed in this paper. The new inverter circuit proposed in this paper is designed and simulated in a simulation environment. The improved topology increases the voltage, reduces the power loss and enhances the various electrical parameters. This enhancement and improvement of electrical quantities is explained with the help of different formulae and figures. With the use of this improve circuitry; the efficiency of the PV Array can be increased. The proposed inverter design and its implementation are given with operational results. Keywords — Inverters, Boost inverter, DC-AC Converter, power semiconductor switches. I. INTRODUCTION Due to the increase in industrial revolution, the world energy demand has also increased. Photovoltaic (PV) system has taken a great attention since it appears to be one of the most promising renewable energy sources. the PV solar generation is preferred over the other renewable energy sources due to the advantages such as absence of fuel cost, cleanliness, pollution free and little maintenance. Solar inverter is a critical component in a solar energy system. It converts DC power output into AC that can be fed into the grid and directly influences the efficiency and reliability of solar energy system. Grid connected PV systems have become very popular because they do not need battery backups to ensure MPPT. The grid can absorb any amount of power and so the maximum utilization of the available solar power is ensured. In this grid connected PV system, the inverter is the heart of the system which is responsible for converting DC power into the required AC power.

In this paper, a Binary Coded Decimal (BCD) topology of modular multilevel inverter with reduced component count is proposed. For the control of this inverter, hybrid control strategy is used. The proposed modular multilevel inverter uses asymmetrical dc sources and reduced number of switches topology. This hybrid modulation technique uses the multicarrier based Pulse Width Modulation (PWM) and the fundamental frequency modulation strategy. The hybrid modulation algorithm is implemented with "NUC140" micro-controller. In comparison with the conventional and some of the recently reported inverter topologies, the proposed inverter topology is able to generate high number of voltage levels in the output by using minimum number of components such as dc sources, power switches and driver circuits. This inverter offers significant performance with less number of components. The feasibility of the proposed topology is confirmed by simulation and experimental results.

- by KARTHIKEYAN VASUDEVAN and +1
- •
- Multi Level Inverters, Hybrid PWM

Nowadays power converters play an important
role in power system and industrial centers. One of the most
important and widely used types of conversion is DC to AC
conversion that is also called inverters. Generally inverters are
divided to voltage source inverter (VSI) and current source
inverter (CSI). From another view the inverters are divided to
two-level and multilevel types. The multilevel inverters are
attractive because of their good output waveform quality.
However, there has been less attention to multilevel current
source inverter (MLCSI) when compared with multilevel VSI.
In this paper, a new topology for MLCSI is proposed. The
proposed topology employs reduced number of switches to
generate desired multilevel output current. The proposed
MLCSI is capable of balancing the currents of the inductors
that are used in the MLCSI structure. A multicarrier PWM
based switching strategy is also proposed for the MLCSI. The
simulation results using PSCAD/EMTDC as well as the
experimental results from a single-phase 5-level CSI laboratory
prototype demonstrate its validity.

- by Abdolhamid Moallemi Khiavi and +1
- •
- Power Electronics, Microprocessors and Microcontrollers, PWM Modulation Converters, Multi Level Inverters

One of the issues of grid-connected photovoltaic systems is the effect of the partial shading on the key parameters and performance of the system. In practice, a share of the entire PV panel may shadded because of the various reasons, inevitably. In this case, the key parameters of the system output are affected with respect to the shading extent and paradigm. In this paper, the effects of the various partial shading patterns on the ouput of the system are examined. This is performed by deriving relevant equations and appropriate modeling of the system and defining different scenarios. The analysis on the system performance is carried out on the dominant output parameters including panel voltage, panel power, and total harmonic distortion (THD) of the inverter. Also, the study considers the effect of using bypass diodes in the panels or not. Addintionally, to compare derived conclusions, the study is implementd on a practical system. The set up is made up of a 7-level multi-level inverter, a Z-source converter, and 1 kW lateral circuitry. The real world test results of the study demonstrate a negligible deviation compared to the simulation results.

The goal of this paper is to compute odometry of vehicle using low-level controls combined with inertial measurement unit. The Low-Level control includes design of Drive-by-Wire mechanisms for steering, brake and accelerator systems with appropriate motors and encoder. Experimentation with encoders and DC motors of steering and brake has been carried out first with various embedded modules to choose best suitable module. The experimentation has led to choosing BeagleBone Black (BBB), A low-cost, open-source community-supported development platform for real-time analysis provided by the TI Sitara AM3358 ARM Cortex-A8 processor with Linux-based operating system. Using BBB dedicated hardware module for high CPR (Counts per Revolution) encoders, the vehicle position is evaluated. Using BBB serial cape, it is interfaced to Roboteq motor controller (used for steering and brake motor) and steering encoder for steering wheel position control. The major task of the paper is the evaluation of odometry from using vehicle rear wheel encoders combined with inertial measurement unit. The paper is carried out on a dune buggy; petrol powered motor vehicle with Ackermann drive platform type and mobility. Initially, Drive-by-wire mechanism for steering, brake and accelerator is designed. Autonomous steering control of vehicle is carried out with feedback from steering motor encoder and steering hand wheel encoder connected to axle of steering system. Using IMU (Inertial Measurement Unit) yaw angle and rear wheel axle encoder position value, the odometry of vehicle are computed. Combined with inertial measurement units, they have proven to be a precise and low-cost sensor for vehicle odometry evaluation.

- by GRD JOURNALS
- •
- MPPT, Multi Level Inverters, PV-BCS
- by Editor IJRET
- •
- Electrical Engineering, Multi Level Inverters

The paper proposes the multilevel current waveform generation with a new configuration H-bridge Current Source Inverter (CSI) from a single DC power source. In this new topology, the H-bridge inverter acts as main circuit and the inductor cells acts as an auxiliary circuit in the generation of multilevel current waveform. This paper describes five level current waveform generation & the sinusoidal pulse width modulation (SPWM) technique is associated with three level shifted multicarrier is introduced in these topology to control the intermediate levels of multilevel current waveform. The main and auxiliary circuits are connected in parallel to generate a multilevel current waveform. The design and performance is evaluated by using MATLAB Simulation.

In a multi-level inverter (MLI), the switching component number effect on volume and reliability is a major concern in on-grid and off-grid applications. The recent trend in MLI, reduced component number of power switches, and capacitors in multi-level inverter topologies have been driven for power conversion. The concept of fault tolerance is not considered in many such configurations; due to this the reliability of the MLI is very low. So now it is a major research concern, to develop a strong fault resilient ability power electronic converter. In this work, a novel configuration of a multilevel inverter with a lower switch count is proposed and analyzed with fault tolerance operation for improvement of reliability. Generally, the fault-tolerant operation is analyzed in only any one of the switches in MLI. But the proposed topology is concerned with multiple switch fault tolerance. Further, the phase disposition pulse width modulation (PDPWM) control scheme is utilized for the operation of the proposed inverter topology. The proposed inverter topology is simulated in MATLAB/Simulink environment under normal and faulty condition; the results are obtained and validated.

- by KARTHIKEYAN VASUDEVAN
- •
- Multi Level Inverters

The multilevel multi-string inverter has gained much attention in recent years due to its advantages in lower switching loss, better electromagnetic compatibility, higher voltage capability, and lower harmonic distortion. Solar Energy is one of the favorable renewable energy resources and the multilevel inverter has been proven to be one of the important enabling technologies in photovoltaic (PV) utilization. As the number of levels increases, it is important to control more switches in parallel with their concurrent processing capability. This paper proposes an IGBT clamped three phase nine levels photovoltaic inverter topology with a multicarrier dual reference pulse-width modulated (PWM) control scheme. Four carrier waves of the fundamental frequency and different amplitudes are compared with two references (a sine wave and its opposite) for generating the control signals of the switches. Some DC/DC boost converters are used to amplify the voltage produced by the photovoltaic generators. Each of these converters is controlled by an MPPT algorithm in order to track the maximum power point of the GPV. Results of simulation in Matlab environment are given and discussed. Keywords— Photovoltaic (PV) system, multilevel three phase multi-string inverter, IGBT clamped inverter, multicarrier PWM.

- by Sabir ouchen
- •
- Multi Level Inverters, Grid connected PV system

Renewable energy sources (RES) gain an importance in recent decades because they are pollution free, easily erectable, and limitless. Among RES, Photovoltaic systems are mostly used as they are light, clean and easily installable. Normally PV cells converts sunlight into electricity in the form of dc. A suitable converter is usually needed to convert the dc power into ac power, which is then injecting into the power grid. The Multilevel Inverters [MLI] can be used to convert the dc into ac for integration of renewable energy sources into the conventional grids. But the conventional MLIs such as Diode Clamped MLIs requires extra diodes in conjunction with the active switches, Flying capacitor MLIs requires extra Capacitors and control also difficult if the levels increases and the Cascaded H-bridge MLIs requires separate dc sources which limits its use. This paper proposes a new type of multi level Inverter which converts the dc into ac using less number of switches when compared to conventional multilevel Inverters. The proposed Inverter can be used to integrate the Photovoltaic system into Grid, with satisfying the grid requirements such as phase angle, frequency and amplitude of the Grid voltage. Seven level and thirteen level proposed MLI is simulated using Matlab/Simulink environment and the corresponding results are presented in this paper. Renewable energy sources are alternatives to our conventional energy sources such as fossil fuels e.g. oil, coal, gas that are not renewable. The conventional energy sources are limited and can be exhausted. Many renewable energy sources are existing such as solar, wind, biomass, hydro, geothermal and ocean power .Among PV has the advantage of clean and no pollution, and etc. So, PV systems are attracting attention in the world [ 1].The basic element of a PV system is the solar cell .A solar cell directly converts the energy of sunlight directly into electricity in the form of dc. Grid interconnection of PV system requires [2-3] an efficient converter to converter the low voltage dc into ac. The conventional H-bridge inverter produces a square output, which contains infinite number of odd harmonics and dvldt stress is also high. Normal PWM inverter can reduces the THD, but switching losses are high and also this inverter is restricted to low power applications. The importance of multilevel inverters [MLI] has been increased since last few decades[4], [5]. These new types of inverters are suitable for high voltage and high power application due to their ability to synthesize waveforms with better harmonic spectrum and with less THD. Generally MUs are classified into three types: they are I.Diode Clamped MUs 2.Flying capacitor MUs 3.Cascaded H-bridge MUs. Diode clamped MUs require large number of clamping diodes as the level increases .In flying capacitor MUs, Switching utilization and efficiency are poor and also it requires large number of capacitors as the level increases and cost is also high. Cascaded H-bridge MUs are mostly preferred [6] for high power applications as the regulation of the DC bus is simple. But it requires separate dc sources and also the complexity of the structure is increases as the level predominantly increase. In order to address the above concerns, this paper proposes a new type of multilevel inverter which requires less number of DC sources and switches compared to Cascaded H-bridge MUs. THD of the output voltage is also less when compared to the conventional MUs. By using this inverter we can efficiently integrate the PV into the existing conventional power grid.

- by IJCRSET JOURNAL
- •
- Multi Level Inverters

Multilevel inverters have
become more popular over the years in
high power electric applications without
use of a transformer and with promise
of less disturbance and reduced
harmonic distortion. This work
proposes three phase Seven level Diode
Clamped Multilevel Inverter (DCMLI)
to simulate various modulating
techniques for induction motor load.
These Pulse Width Modulation (PWM)
techniques include Carrier Overlapping
(CO) strategy, Variable Frequency (VF)
strategy, Phase Shift (PSPWM) strategy
and Sub-Harmonic Pulse Width
Modulation (SHPWM) i.e. Phase
Disposition (PD) strategy, Phase
Opposition Disposition (POD) strategy
and Alternate Phase Opposition
Disposition (APOD) strategy. The Total
Harmonic Distortion (THD), VRMS
(fundamental), crest factor, form factor
and distortion factor are evaluated for
various modulation indices. Simulation
is performed using MATLABSIMULINK.

- by swarupa kunsoth
- •
- Electrical Engineering, Matlab, PWM, Simulink

This paper presents the design and FPGA embedded
implementation of robust controller design to
speed tracking problem for a Permanent Magnet Synchronous
Motor (PMSM). Then, a linear controller
based on the exact static error dynamics passive output
feedback (ESEDPOF) is proposed, where the uncertainty
estimation is taken into account. The technique
of passivity requires knowing the load torque,
this is estimated with a traditional reduced-order observer.
PMSM is driven by a five levels Three-Phase
Cascaded Cell Multi-Level Inverter (3-CCMLI). The
medium-scale field-programmable gate array (FPGA)
Spartan-6 XC6SLX9 is used for implementing the
ESEDPOF controller, the reduced-order observer,
and the multilevel pulse width modulator. The parallel
processing provided by these devices allowed to
obtain a sampling time of 10us. Simulation and Experimental
validation shows an excellent dynamical
performance.

The first generation of multi-machine systems is limited on two .the first configuration consists of a continuous floor which feeds several three-phase inverters connected in parallel, or each inverter supplies a three-phase machine .the control of each machine is independent via its inverter and its algorithm control .the second configuration consists of a single inverter, which also feeds in parallel three phase machines .for this structure, the machines must have the same speed and suffer the same torque load .these two conditions make the use of this system in a limited scope .It is impossible to connect in series several three-phase machines powered by a single-phase power converter and that each machine in the group have an independent speed control .but, the use of multi-phase converters associated with polyphase machine. generate additional degrees of freedom .With these, several polyphase machines can be connected in series in an appropriate transposition phases. The objective of this work is to order, model and characterize the behavior of a training system multimachines composed of two five phase synchronous permanent magnet motors connected in series and powered by a five phase matrix converter applied to the rail traction.

Many industries used multilevel inverter in high-voltage applications, this transformer attains many merits such power factor rectification, product voltage arranging from power transmission and reduction of overall harmonic distortions with a two-level inverter installed. As the numeral of planes growing, producing waveform which has more steps, resulting in a sine wave that oncoming very closely to the in-demand wave, so the waveforms with higher quality as THD approaches zero (reducing harmonics her the harmonic deformation rate of single-phase from three-thirteen (three, five, seven, nine, eleven and thirteen) level AC-DC converter will be presented.

- by Othman Anssari
- •
- total harmonic distortion (THD), Multi Level Inverters

This paper, investigates the Common Mode Voltage (CMV)between neutral point of the star connected RL load and system ground.CMV also known as zero sequence voltage results in adverse effects like bearing currents, shaft voltages and electromagnetic interference.CMV also causes premature failure of bearings of induction motor and is necessary to reduce. In this paper, Variable Frequency Sinusoidal Pulse Width Modulation (VFSPWM) techniques are used to investigate CMV in Cascaded H-Bridge Multilevel Inverter (CHB-MLI). Comparison of 5-level CHB-MLI with equal and unequal DC sources in terms of CMV is also presented. Simulation of circuit is carried out in MATLAB environment.

- by Mohd Esa
- •
- Multi Level Inverters

The aim of this paper is to determine the Total harmonic distortion (THD) of three phase three level flying capacitor inverter fed star connected R-L load. The modulation Techniques used is Phase Disposition Sinusoidal pulse width modulation (PD-SPWM) and Phase Opposition Disposition Sinusoidal pulse width modulation (POD-SPWM).The Modulation index is varied to analyze its effect on Current THD and Voltage THD.This paper also presents the comparison of PD-SPWM and POD-SPWM controlled Flying capacitor Inverter in terms of THD. The simulation result shows that PD-SPWM has better performance when compared to POD-SPWM. The simulation of circuit is done by using MATLAB/Simulink.

- by Mohd Esa
- •
- Multi Level Inverters, Harmonics, Dc-Ac Inverter Using Spwm

— The paper discusses a detailed study of unified power quality conditioner (UPQC) which is a combination of series active filter and shunt active filter. It performs simultaneous series and shunt compensation in the power distribution system. In series compensation , the device makes the distribution bus voltage si-nusoidal irrespective of voltage unbalance. In shunt compensation, the device offers the load compensation which results into sinusoidal current drawn by the non-linear load irrespective of current harmonics and current imbalance at distribution system bus. We shall discuss the structure and control strategy for UPQC device. A control strategy is based upon unit vector template generation and hysteresis controller. Effective Simulations are presented to validate the proposed structure and control.

- by Prasad Wankhade and +1
- •
- Digital Control System, Multi Level Inverters, Power electronic DC-DC converters, LLC resonant converters

This paper presents the novel particle swarm
optimization technique to determine the optimum switching
angles of multilevel converters so as to produce the required
fundamental voltage while at the same time not generate lower
order harmonics. This optimization method is applied to
transcendental equations characterizing the harmonic content to
minimize low order harmonics. All set of solutions are found for
seven and eleven levels inverters to show the simplicity and
effectiveness of proposed method.

- by Mehrdad Tarafdar Hagh
- •
- Artifical Intelligence, Multi Level Inverters

In this paper, new types of pulse width modulation techniques are proposed to improve the performance of multi-level inverter. The effort is taken for this performance improvement without making any changes in the material of the multi-level inverter. Multi-level inverter performance depends on pulse width modulation technique adopted in it. The proposed techniques have the characteristics of exhibiting less total harmonic distortion. The output voltage is also improved. In this paper, these proposed techniques are applied to multi-level inverter and the performances are evaluated. It is simulated in MATLAB/Simulink and the results are obtained. The results are compared with the conventional method to look into its validity.

- by Y.V.Siva Reddy
- •
- Computer Science, total harmonic distortion (THD), Inverter, Spwm

- by Boubekeur Azoui
- •
- Computer Science, Multi Level Inverters, Grid connected PV system

Multilevel Inverters are generally utilized for medium voltage and high power applications. Invented in 1975, MLIs have brought huge change in the field of Electrical and Electronics. It contains distinctive topologies. This paper proposes a photovoltaic aided multilevel inverter with Reverse Voltage topology with diminished number of switches. In comparison to other existing topologies this topology utilizes minimum number of switches and less number of carrier signals which in turns diminishes the complexity of the system as well as cost. The proposed framework contains five MOSFETs, five diodes to create eleven levels. In this topology the SPWM strategy has been utilized. This topology utilizes one sine wave and five triangular waves, which is half in comparison to the existing topologies. As sustainable power sources can be utilized for multilevel inverter, photovoltaic cell has been utilized. The MATLAB recreation for both solar powered module and Multilevel inverter has been appeared alongside the equipment approach.

This paper aims to study the multi-level inverter (MLI) fed the widely used doubly-fed induction generators (DFIG). The new DFIG generator connected to the electrical grid is evaluated during single-pole autoreclosure operation to continue the generator support to the system. The effect of using MLI on the performance of the DFIG system during the dynamic operation of the autoreclosure is studied for the first time and integrating a new MLI during the fault and clearing periods. A dynamic arc model is represented depending on Kizilcay model. Furthermore, the dynamics performance of the DFIG during integration with MLI to improve the performance is studied. The MLI is preferred because of processing high power with high resolution of the voltage waveforms and lower stresses on switches. The MLI enhances the performance of DFIG-based generating system associated with electrical grid system in case of single-pole autoreclosure. The proposed cases of studies are simulated using Matlab/Simulink to evaluate the proposed system performance during the autoreclosure operation for faults in double-circuit transmission systems.

Estimation of optimum switching angles for multilevel converters so as to produce the required fundamental voltage while at the same time eliminate specified lower order harmonics through Artificial Neural Networks (ANNs) is presented. The proposed technique uses the best performance solutions (lowest THD solutions) as the training data set for proposed ANN system. This technique can be applied to multilevel inverters with any number of levels. As an example, in this paper estimation results of optimum switching angles are given for seven levels inverter to eliminate the 5th and 7th harmonics. After training the proposed ANN system, a large and memory-demanding look-up table replaced with trained neural network to generate the optimum switching angles with lowest THD for a given modulation index. The simulation results are presented in PSCAD/EMTDC software package to validate the accuracy of estimation results by proposed ANN system.

This paper presents a novel shunt active power filter (SAPF). The power converter that is used in this SAPF is constructed from a four-leg asymmetric multi-level cascaded H-bridge (CHB) inverter that is fed from a photovoltaic source. A three-dimensional space vector modulation (3D-SVPWM) technique is adopted in this work. The multi-level inverter can generate 27level output with harmonic content is almost zero. In addition to the capability to inject reactive power and mitigating the harmonics, the proposed SAPF has also, the ability to inject real power as it is fed from a PV source. Moreover, it has a fault-tolerant capability that makes the SAPF maintaining its operation under a loss of one leg of the multi-level inverter due to an open-circuit fault without any degradation in the performance. The proposed SAPF is designed and simulated in MATLAB SIMULINK using a single nonlinear load and the results have shown a significant reduction in total harmonics distortion (THD) of the source current under the normal operating condition and post a failure in one phase of the SAPF. Also, similar results are obtained when IEEE 15 bus network is used.

- by Mohd Esa
- •
- Electrical Engineering, Multilevel Inverter, Multi Level Inverters

Recently, Re-boost seven-level inverter has been developed as an alternative between Photovoltaic system and single-phase load. DC level is increased using a re-boost regulator and its output is rehabilitated into single-phase AC utilizing a seven-level inverter. The re-boost converter is utilized to escalate the voltage gain. The objective of the suggested closed loop Re-boost Seven Level Inverter fed Induction Motor (RBSLIIM) system is to enhance the dynamic response of RBSLIIM using FO-P-I-D controller. Simulink models are developed for P-I and FO-P-I-D controlled RBSLIIM systems. The results of P-I and FO-P-I-D based RBSLIIM systems indicate that the voltage response with FO-P-I-D is superior to P-I controlled RBSLIIM system.

DPFC is proposed in the present work to improve voltage stability of fourteen bus system during line interruption. The voltage across the load decreases due to the interruption of the line. State space method is used to calculate Line currents and bus voltages. The ability of DPFC to bring voltage, real power and reactive power to normal level is presented in this paper. The simulation results for healthy system, line interrupted system without DPFC and with DPFC are presented. The results of comparative study are presented to show the improvement in power quality. The simulation studies indicate that the power flow with DPFC during line outage is almost equal to the power during healthy condition.

In this paper, analysis and modelling of a single-phase cascaded full-bridge resonance inverter are considered. The control of proposed inverter by full-wave phase method at high frequency is implemented. In the first step, MATLAB/Simulink environments are used to simulate the model and show obtained results of waveforms. The second step is the experimental validation of simulation results by a realization of the inverter and generated signals. The Root-Mean-Squared voltage of a capacitor waveform between 3 and 7 kHz frequency with simulation and realization are presented, comparatively, for a comparison. The results obtained are satisfactory and show the efficiencies of analysis and the proposed model of the full-bridge resonance inverter.

- by Fayçal CHABNI
- •
- Power Electronics, Electronics, Genetic Algorithms, Optimization techniques

Estimation of optimum switching angles for multilevel converters so as to produce the required fundamental voltage while at the same time eliminate specified lower order harmonics through Artificial Neural Networks (ANNs) is presented. The proposed technique uses the best performance solutions (lowest THD solutions) as the training data set for proposed ANN system. This technique can be applied to multilevel inverters with any number of levels. As an example, in this paper estimation results of optimum switching angles are given for seven levels inverter to eliminate the 5th and 7th harmonics. After training the proposed ANN system, a large and memory-demanding look-up table replaced with trained neural network to generate the optimum switching angles with lowest THD for a given modulation index. The simulation results are presented in PSCAD/EMTDC software package to validate the accuracy of estimation results by proposed ANN system.

In this paper, the elimination of harmonics in a cascade multilevel inverter by considering the nonequality of
separated dc sources by using particle swarm optimization is
presented. Solving a nonlinear transcendental equation set
describing the harmonic-elimination problem with nonequal dc
sources reaches the limitation of contemporary computer algebra software tools using the resultant method. The proposed approach in this paper can be applied to solve the problem in a simpler manner, even when the number of switching angles is increased and the determination of these angles using the resultant theory approach is not possible. Theoretical results are verified by experiments and simulations for an 11-level H-bridge inverter. Results show that the proposed method does effectively eliminate a great number of specific harmonics, and the output voltage is resulted in low total harmonic distortion.