This document summarizes a research paper that investigates using a cascade multilevel inverter to control an induction motor via direct torque control (DTC). It begins by introducing multilevel inverters and their benefits for high power applications. It then describes the cascade H-bridge topology and symmetrical vs asymmetrical configurations. The document outlines DTC for controlling induction motors and discusses extending this technique to multilevel inverters. It presents the torque and flux estimation methods used in DTC as well as the voltage vector selection process. The research aims to optimize DTC for induction motors powered by a cascade multilevel inverter.
One of the preferred choices of electronic power conversion for high power applications are multilevel inverters topologies finding increased attention in industry. Cascaded H-Bridge multilevel inverter is one of these topologies reaching the higher output voltage, power level and higher reliability due to its modular topology. Level Shifted Carrier Pulse Width Modulation (LSCPWM) and Phase Shifted Carrier Pulse Width Modulation are used generally for switching cascaded H-bridge (CHB) multilevel inverters. This paper compares LSCPWM and PSCPWM in terms of total harmonics distortion (THD) and output voltage among inverter cells. Simulation for 21-level CHB inverter is carried out in MATLAB/SIMULINK and simulation results are presented.
A Single Phase Eleven Level Cascaded H-Bridge Multilevel Inverter for Photovo...IJMER
Abstract: A Cascaded H-Bridge Multilevel Inverter is a power electronic converter built to synthesize a desired ac voltage
from several levels of dc voltages with better harmonic spectrum. Such inverters are suitable for high voltage and high
power applications and have been an important development in recent years. This paper presents the performance of a
eleven level cascaded H-Bridge multilevel inverter topology with multicarrier pulse width modulation technique for
photovoltaic cell. This inverter is capable of producing eleven levels of output voltage from the dc supply voltage. This
topology magnifies the fundamental output voltage with reduction in total harmonic distortion . The output is drawn near the
sine wave because of more levels. It can also be easily extended to an m-level inverter. The performance of the proposed
PWM strategy in terms of output voltage and THD is shown using MATLAB/Simulink.
Keywords: Multilevel inverter, Cascaded H-Bridge multilevel inverter, Multicarrier pulse width modulation, PV cell, Total
harmonic distortion.
A novel single phase cascaded h-bridge inverter with new cell configuration a...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
6.[36 45]seven level modified cascaded inverter for induction motor drive app...Alexander Decker
1) The document presents a modified cascaded multilevel inverter topology for induction motor drive applications that reduces the number of switches compared to conventional designs.
2) The proposed topology uses 7 switches and 3 diodes to generate 7 voltage levels, whereas conventional designs require 12 switches. This reduces switching losses, cost, and complexity.
3) Simulation and experimental results show the proposed design can generate 7 voltage levels to drive an induction motor. FFT analysis shows lower total harmonic distortion compared to conventional designs.
This document describes an 11-level cascaded H-bridge grid-tied inverter interface with solar panels. It uses three H-bridge inverters connected to 200W solar panels each. MATLAB is used for maximum power point tracking and phase locking to optimize inverter output when connected to the power grid. The proposed system has 11% harmonic distortion, lower than the IEEE standard of 15%. It provides benefits over traditional three-level inverters which have 46% total harmonic distortion. Block diagrams and the hardware and software requirements are presented. Applications include industrial equipment and high power inverters.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Modified cascaded multilevel inverter with ga to reduce line to line voltage thdIAEME Publication
This document summarizes a research paper on a modified cascaded multilevel inverter with genetic algorithm optimization to reduce line-to-line voltage total harmonic distortion. The proposed inverter uses an H-bridge topology with a multi-conversion cell consisting of three voltage sources and switches to produce a seven-level output with reduced switch count compared to a conventional cascaded multilevel inverter. Genetic algorithm is used to determine optimal switching angles to minimize the line voltage THD while maintaining the desired fundamental output voltage. Simulation results show the modified inverter achieves lower THD than the conventional design using fewer switches.
A comparative study of cascaded h bridge and reversing voltage multilevel inv...IAEME Publication
This document compares a cascaded H-bridge multilevel inverter topology to a proposed reversing voltage multilevel inverter topology. The cascaded H-bridge requires more components as the number of levels increases, making it less reliable. The proposed reversing voltage topology separates output voltage generation into level generation and polarity generation parts, requiring fewer switches. Specifically, a 7-level example of each topology is compared in terms of total harmonic distortion and number of components. The proposed topology is shown to require fewer components and produce lower THD than the cascaded H-bridge topology.
One of the preferred choices of electronic power conversion for high power applications are multilevel inverters topologies finding increased attention in industry. Cascaded H-Bridge multilevel inverter is one of these topologies reaching the higher output voltage, power level and higher reliability due to its modular topology. Level Shifted Carrier Pulse Width Modulation (LSCPWM) and Phase Shifted Carrier Pulse Width Modulation are used generally for switching cascaded H-bridge (CHB) multilevel inverters. This paper compares LSCPWM and PSCPWM in terms of total harmonics distortion (THD) and output voltage among inverter cells. Simulation for 21-level CHB inverter is carried out in MATLAB/SIMULINK and simulation results are presented.
A Single Phase Eleven Level Cascaded H-Bridge Multilevel Inverter for Photovo...IJMER
Abstract: A Cascaded H-Bridge Multilevel Inverter is a power electronic converter built to synthesize a desired ac voltage
from several levels of dc voltages with better harmonic spectrum. Such inverters are suitable for high voltage and high
power applications and have been an important development in recent years. This paper presents the performance of a
eleven level cascaded H-Bridge multilevel inverter topology with multicarrier pulse width modulation technique for
photovoltaic cell. This inverter is capable of producing eleven levels of output voltage from the dc supply voltage. This
topology magnifies the fundamental output voltage with reduction in total harmonic distortion . The output is drawn near the
sine wave because of more levels. It can also be easily extended to an m-level inverter. The performance of the proposed
PWM strategy in terms of output voltage and THD is shown using MATLAB/Simulink.
Keywords: Multilevel inverter, Cascaded H-Bridge multilevel inverter, Multicarrier pulse width modulation, PV cell, Total
harmonic distortion.
A novel single phase cascaded h-bridge inverter with new cell configuration a...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
6.[36 45]seven level modified cascaded inverter for induction motor drive app...Alexander Decker
1) The document presents a modified cascaded multilevel inverter topology for induction motor drive applications that reduces the number of switches compared to conventional designs.
2) The proposed topology uses 7 switches and 3 diodes to generate 7 voltage levels, whereas conventional designs require 12 switches. This reduces switching losses, cost, and complexity.
3) Simulation and experimental results show the proposed design can generate 7 voltage levels to drive an induction motor. FFT analysis shows lower total harmonic distortion compared to conventional designs.
This document describes an 11-level cascaded H-bridge grid-tied inverter interface with solar panels. It uses three H-bridge inverters connected to 200W solar panels each. MATLAB is used for maximum power point tracking and phase locking to optimize inverter output when connected to the power grid. The proposed system has 11% harmonic distortion, lower than the IEEE standard of 15%. It provides benefits over traditional three-level inverters which have 46% total harmonic distortion. Block diagrams and the hardware and software requirements are presented. Applications include industrial equipment and high power inverters.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Modified cascaded multilevel inverter with ga to reduce line to line voltage thdIAEME Publication
This document summarizes a research paper on a modified cascaded multilevel inverter with genetic algorithm optimization to reduce line-to-line voltage total harmonic distortion. The proposed inverter uses an H-bridge topology with a multi-conversion cell consisting of three voltage sources and switches to produce a seven-level output with reduced switch count compared to a conventional cascaded multilevel inverter. Genetic algorithm is used to determine optimal switching angles to minimize the line voltage THD while maintaining the desired fundamental output voltage. Simulation results show the modified inverter achieves lower THD than the conventional design using fewer switches.
A comparative study of cascaded h bridge and reversing voltage multilevel inv...IAEME Publication
This document compares a cascaded H-bridge multilevel inverter topology to a proposed reversing voltage multilevel inverter topology. The cascaded H-bridge requires more components as the number of levels increases, making it less reliable. The proposed reversing voltage topology separates output voltage generation into level generation and polarity generation parts, requiring fewer switches. Specifically, a 7-level example of each topology is compared in terms of total harmonic distortion and number of components. The proposed topology is shown to require fewer components and produce lower THD than the cascaded H-bridge topology.
This document provides a list of 57 technical papers published between 2010-2013 related to electrical engineering topics like power electronics, renewable energy, and control systems. It includes the paper titles and their respective years of publication. Contact information is also provided to inquire about further details.
This paper presented single DC bus single phase seven level cascaded H-bridge (CHB) inverter for multi-panel photovoltaic grid-connected applications. A single DC bus supplying flyback converters to produce DC link voltages for CHB cells is suggested. A balanced operation of CHB inverter cells is obtained irrespective to power unbalance occurred by individual maximum power point tracking boost converter of photovoltaic (PV) panels due to the non-uniform irradiation and partial shading. A DC bus voltage control system with addition of estimated DC bus ripple voltage to the reference is proposed to eliminate the second order harmonic contained in the feedback voltage of DC bus enabling to design high bandwidth of DC voltage control loop. This produces fast dynamic response, low total harmonic distortion (THD) of grid current and smaller DC bus capacitance. Mathematical modeling of bus voltage control system is presented. PSIM simulation program is used and the simulation results are obtained to validate the proposed control system.
Power conditioning circuits are required for the fuel cell systems due to its nature in energetic state. This paper proposed the small signal average modelling of a duel active bridge (DAB) DC-DC converter with LC filter, to generate the single phase AC power by using the H1000 fuel cell system. The controller is designed for the stable operation of the system. Implemented the controller, which gives the constant output voltage to DC-bus from the DAB DC-DC converter, this DC-bus voltage fed to the inverter, which inverts the DC-bus voltage to single Phase AC power with the LC-filter. The proposed system simulated in the MATLAB/Simulink.
This document presents a new topology for a cascaded multilevel inverter powered by a photovoltaic system. The proposed system uses a high frequency transformer to generate the DC bus voltage for an auxiliary inverter from the main inverter's DC bus. This reduces the number of isolated DC sources needed by half, lowering costs. A natural balancing of voltages between the main and auxiliary inverters is achieved through the transformer turns ratio, simplifying control. The system was simulated using static loads to validate the control scheme.
A New Configuration of Asymmetric Multilevel Converter to Maximize the Number...IJMTST Journal
The multilevel converters are increasingly becoming popular because of its high power applications. This research paper describes about the new structure that can produce increased number of output voltage waveform using a single source and reduced number of power electronic components. In designing a multilevel converter, the power electronic switches play a very imperative role as it describes the installation area, cost, configuration complexity and may more things that play a significant role while designing. The prime function of multilevel converter is to abolish total harmonic distortion and to incorporate desired ac voltage from several separate dc sources. Each level consists of H-Bridge converter units. High efficiency, high voltage capability, lower switching losses are its prime advantages. A multilevel power converter structure can be introduced as an alternative in medium voltage and high power situations. This structure not only achieves high power ratings but also empower the use of renewable energy sources. It finds its basic application in adjustable speed drives, Static Compensator (STATCOM).
Cascaded H-BRIDGE Converter for Domestic ApplicationsIJTET Journal
1) The document presents a five-level cascaded H-bridge multilevel inverter that uses separate DC sources from solar panels for each level.
2) The inverter is simulated using MATLAB and produces a five-level stepped voltage waveform as the output.
3) The cascaded H-bridge topology has advantages of modular structure, low component count per level, and potential for soft switching. It can be used for applications such as UPS, battery charging, and electric vehicles.
A hybrid cascaded multilevel converter for battery 2Ki Tu
This document describes a hybrid cascaded multilevel converter proposed for use in electric vehicle battery energy management systems. The converter consists of half-bridge converters connected to each individual battery cell that can control whether the cell is connected to or bypassed from the circuit. All the half-bridges are cascaded to output a multi-level staircase voltage. An H-bridge converter then changes the direction of the DC bus voltages to generate AC voltages for driving the motor. The converter allows for independent control and balancing of each battery cell's state of charge while generating cleaner multilevel output voltages suitable for motor drives.
An Improved Single Phase Transformer less Inverter Topology for Cost Effecti...IJMER
In grid connected PV systems, the elimination of isolation transformer introduces common
mode leakage current due to the parasitic capacitance between PV panels and the ground. The common
mode leakage current reduces the efficiency of power conversion stage, affects the quality of grid
current, deteriorate the electric magnetic compatibility and give rise to various safety threats. In order
to eliminate the leakage current, an improved transformer less topology with virtual DC bus concept is
proposed here. By connecting the grid neutral line directly to the negative pole of the DC bus, the stray
capacitance between the PV panels and the ground is bypassed. The topology consists of only five power
switches, two capacitors and the filter section. Therefore, the power electronics cost can be curtailed.
This advanced topology can be modulated with the sinusoidal pulse width modulation (SPWM) to reduce
the output current ripple. The simulation result of the proposed topology using MATLAB/SIMULINK is
presented.
In this paper the multicarrier pulse width modulation (MCPWM) with multi value DC voltage source multilevel inverter is presented. These MLI’s are suitable in high voltage & high power application due to their ability to synthesize waveforms with better harmonic spectrum. Seven level inverter is simulated using MATLAB/Simulink. The use of Photovoltaic Cell as a DC source for the multilevel Inverter is proposed here.
Performance and Analysis of Hybrid Multilevel Inverter fed Induction Motor Drivernvsubbarao koppineni
This paper presents the Five level inverter with single DC source which is used to generate a five level output with two bridges and six switches and performance of three phase induction motor is analyzed when connected to PV array For this two identical dc sources of 50V each for two bridges in five levels using Multi level inverter and five level output is obtained by using a single DC source of 100V with six switches. A virtual DC source (charged capacitor acts as virtual DC source) is used for getting the output. The same technique is implemented for three-phase circuit i.e. by using single DC source. An asynchronous motor (three-phase) is connected as load and its performance characteristics are analyzed. And further the DC source is replaced by a renewable resource such as solar panels, fuel cell etc. and DC voltage is obtained. Performance characteristics of three-phase asynchronous motor are analyzed with PV array connected. The method can be easily extended to an m-level inverter.
This paper presents the detail circuitry modeling of single phase off-grid inverter for small standalone system applications. The entire model is developed in MATLAB/Simulink platform using circuitry model. This off grid inverter consists of a high frequency DC-DC step up converter cascaded with a full bridge PI control voltage source inverter using SPWM modulation with LC filter to produce sine wave output. This is a common design used in many small commercial off-grid inverter. This off-grid inverter model is capable to produce AC sinewave output voltage at 230 V 50 Hz up to 1 kW power from a 48 V DC lead acid battery source. The AC sine wave output waveform achieved a voltage Total Harmonic Distortion (THD) of less than 1 % which is almost a pure sine wave. The conversion efficiency performance of the off-grid inverter achieved more than 94 %. The performance of the model is validated by real commercial off-grid inverter. The performance validation experiment shows that the off-grid inverter Simulink model conversion efficiency and THD performance are comparable to the commercial off-grid inverter. This model contributes to assist small to medium standalone system load and battery sizing design with greater accuracy.
Here are the key characteristics of a good inverter:
- Sinusoidal output voltage waveform
- High gain
- Controllable output voltage and frequency
- Low power requirement for control circuitry
- Low cost
- Long working life
- Semiconductor devices with minimal switching and conduction losses
This document presents a comparison of different carrier-based pulse width modulation (PWM) strategies for controlling a five-level Z-source diode-clamped inverter. It first provides background on multilevel inverters and Z-source inverters. It then describes the operating principles of the Z-source inverter and equations for its output voltage. Simple boost control is presented as the control method. Three carrier-based PWM strategies - alternative phase opposition disposition, phase opposition disposition, and phase disposition - are described and their performance is evaluated through MATLAB simulations. The results show that alternative phase opposition disposition provides the highest output voltage boost but also the highest total harmonic distortion, while phase disposition has the lowest boost but also the lowest harmonic
IRJET- Comparative Analysis for Power Quality Improvenment of Cascaded an...IRJET Journal
This document compares the performance of cascaded and capacitor-clamped multilevel inverters. It analyzes the output voltage waveforms and total harmonic distortion of 3-level and 5-level configurations of each inverter topology. The cascaded inverter uses H-bridge cells with separate DC sources, while the capacitor-clamped inverter uses capacitors to transfer voltage between stages. Simulation results in MATLAB/Simulink show the voltage waveforms and fast Fourier transform analysis for each configuration. The cascaded inverter requires fewer components but separate DC sources, while the capacitor-clamped inverter requires voltage balancing of capacitors.
This paper proposes maximum boost control for 7-level z-source cascaded h-bridge inverter and their affiliation between voltage boost gain and modulation index. Z-source network avoids the usage of external dc-dc boost converter and improves output voltage with minimised harmonic content. Z-source network utilises distinctive LC impedance combination with 7-level cascaded inverter and it conquers the conventional voltage source inverter. The maximum boost controller furnishes voltage boost and maintain constant voltage stress across power switches, which provides better output voltage with variation of duty cycles. Single phase 7-level z-source cascaded inverter simulated using matlab/simulink.
A Novel Three Phase Multilevel Inverter with Single DC Link for Induction Mot...IJECEIAES
1) The document presents two configurations of a novel three-phase eleven-level multilevel inverter with a reduced number of switches for induction motor drive applications.
2) Configuration 1 uses separate DC sources for each phase, requiring 24 switches total. Configuration 2 uses a single common DC source for all three phases, also requiring 24 switches.
3) Both configurations are simulated in Matlab/Simulink. Results show the inverter produces a three-phase voltage of 600V peak-to-peak and supplies 50A to an induction motor, driving it at 1400rpm with 10N-m of torque.
This document describes the modeling and design of a five-level cascaded H-bridge multilevel inverter with a DC/DC boost converter. It begins with an introduction to multilevel inverters and their advantages over traditional two-level inverters. It then discusses the specific topology of a five-level cascaded H-bridge inverter and describes the operation and components of a DC/DC boost converter. Simulation results in MATLAB/Simulink are presented, showing the output voltage waveform both with and without filtering. The total harmonic distortion of the output is analyzed, showing less than 5% distortion. The conclusion is that this five-level inverter topology with boost converter provides high efficiency of 95% and improved power
Harmonic Analysis of Seven and Nine Level Cascade Multilevel Inverter using M...IAES-IJPEDS
The use of multilevel inverters has become popular in recent years for high- power applications. Multilevel Inverters are power converter systems composed by an array of power semiconductor sources that when properly connected and controlled can generate a multistep voltage waveform with variable and controllable frequency, phase and amplitude. This study deals with the comparison of a 7-level inverter with a 9-level inverter system; the voltage source inverters (VSI) are modelled and simulated using MATLAB Simulink and the results are presented. The test results verify the effectiveness of the proposed strategy in terms of computational efficiency as well as the capability of the inverter to produce very low distorted voltage with low-switching losses. This research aims to extend the knowledge about the performance of different clamped multilevel inverter through harmonic analysis. Simulations results validate up to the mark performance of the mentioned topologies.
BE-EEE-8th sem project report for the project titled "Asymmetrical Multilevel...MOHAMMED SAQIB
This document discusses asymmetrical multilevel inverters for producing higher output voltage levels. It introduces multilevel inverters and their advantages over traditional two-level inverters. The cascaded H-bridge topology requires fewer components and is suitable for high power applications. Asymmetric cascaded H-bridge topologies can produce more voltage levels using different DC source voltages. The document proposes a new asymmetric bidirectional converter topology that uses contradictory ratios of DC voltages to generate a higher number of output voltage levels using fewer switches. Simulation results will validate that this topology can achieve a seven-level output from two H-bridges with reduced total harmonic distortion.
Concept Kit 3-Phase AC Motor Drive Simulation (PSpice Version)Tsuyoshi Horigome
This document provides an overview of modeling a 3-phase AC motor for electric drive system simulation in PSpice. It includes the motor specifications, modeling of torque and back-EMF, a simplified 3-phase AC motor model, the equivalent circuit model, and appendices describing simulation settings and evaluation. The modeling aims to simulate phase current, back-EMF, speed, torque, power output and efficiency characteristics of the 3-phase AC motor under different load conditions.
This document provides a list of 57 technical papers published between 2010-2013 related to electrical engineering topics like power electronics, renewable energy, and control systems. It includes the paper titles and their respective years of publication. Contact information is also provided to inquire about further details.
This paper presented single DC bus single phase seven level cascaded H-bridge (CHB) inverter for multi-panel photovoltaic grid-connected applications. A single DC bus supplying flyback converters to produce DC link voltages for CHB cells is suggested. A balanced operation of CHB inverter cells is obtained irrespective to power unbalance occurred by individual maximum power point tracking boost converter of photovoltaic (PV) panels due to the non-uniform irradiation and partial shading. A DC bus voltage control system with addition of estimated DC bus ripple voltage to the reference is proposed to eliminate the second order harmonic contained in the feedback voltage of DC bus enabling to design high bandwidth of DC voltage control loop. This produces fast dynamic response, low total harmonic distortion (THD) of grid current and smaller DC bus capacitance. Mathematical modeling of bus voltage control system is presented. PSIM simulation program is used and the simulation results are obtained to validate the proposed control system.
Power conditioning circuits are required for the fuel cell systems due to its nature in energetic state. This paper proposed the small signal average modelling of a duel active bridge (DAB) DC-DC converter with LC filter, to generate the single phase AC power by using the H1000 fuel cell system. The controller is designed for the stable operation of the system. Implemented the controller, which gives the constant output voltage to DC-bus from the DAB DC-DC converter, this DC-bus voltage fed to the inverter, which inverts the DC-bus voltage to single Phase AC power with the LC-filter. The proposed system simulated in the MATLAB/Simulink.
This document presents a new topology for a cascaded multilevel inverter powered by a photovoltaic system. The proposed system uses a high frequency transformer to generate the DC bus voltage for an auxiliary inverter from the main inverter's DC bus. This reduces the number of isolated DC sources needed by half, lowering costs. A natural balancing of voltages between the main and auxiliary inverters is achieved through the transformer turns ratio, simplifying control. The system was simulated using static loads to validate the control scheme.
A New Configuration of Asymmetric Multilevel Converter to Maximize the Number...IJMTST Journal
The multilevel converters are increasingly becoming popular because of its high power applications. This research paper describes about the new structure that can produce increased number of output voltage waveform using a single source and reduced number of power electronic components. In designing a multilevel converter, the power electronic switches play a very imperative role as it describes the installation area, cost, configuration complexity and may more things that play a significant role while designing. The prime function of multilevel converter is to abolish total harmonic distortion and to incorporate desired ac voltage from several separate dc sources. Each level consists of H-Bridge converter units. High efficiency, high voltage capability, lower switching losses are its prime advantages. A multilevel power converter structure can be introduced as an alternative in medium voltage and high power situations. This structure not only achieves high power ratings but also empower the use of renewable energy sources. It finds its basic application in adjustable speed drives, Static Compensator (STATCOM).
Cascaded H-BRIDGE Converter for Domestic ApplicationsIJTET Journal
1) The document presents a five-level cascaded H-bridge multilevel inverter that uses separate DC sources from solar panels for each level.
2) The inverter is simulated using MATLAB and produces a five-level stepped voltage waveform as the output.
3) The cascaded H-bridge topology has advantages of modular structure, low component count per level, and potential for soft switching. It can be used for applications such as UPS, battery charging, and electric vehicles.
A hybrid cascaded multilevel converter for battery 2Ki Tu
This document describes a hybrid cascaded multilevel converter proposed for use in electric vehicle battery energy management systems. The converter consists of half-bridge converters connected to each individual battery cell that can control whether the cell is connected to or bypassed from the circuit. All the half-bridges are cascaded to output a multi-level staircase voltage. An H-bridge converter then changes the direction of the DC bus voltages to generate AC voltages for driving the motor. The converter allows for independent control and balancing of each battery cell's state of charge while generating cleaner multilevel output voltages suitable for motor drives.
An Improved Single Phase Transformer less Inverter Topology for Cost Effecti...IJMER
In grid connected PV systems, the elimination of isolation transformer introduces common
mode leakage current due to the parasitic capacitance between PV panels and the ground. The common
mode leakage current reduces the efficiency of power conversion stage, affects the quality of grid
current, deteriorate the electric magnetic compatibility and give rise to various safety threats. In order
to eliminate the leakage current, an improved transformer less topology with virtual DC bus concept is
proposed here. By connecting the grid neutral line directly to the negative pole of the DC bus, the stray
capacitance between the PV panels and the ground is bypassed. The topology consists of only five power
switches, two capacitors and the filter section. Therefore, the power electronics cost can be curtailed.
This advanced topology can be modulated with the sinusoidal pulse width modulation (SPWM) to reduce
the output current ripple. The simulation result of the proposed topology using MATLAB/SIMULINK is
presented.
In this paper the multicarrier pulse width modulation (MCPWM) with multi value DC voltage source multilevel inverter is presented. These MLI’s are suitable in high voltage & high power application due to their ability to synthesize waveforms with better harmonic spectrum. Seven level inverter is simulated using MATLAB/Simulink. The use of Photovoltaic Cell as a DC source for the multilevel Inverter is proposed here.
Performance and Analysis of Hybrid Multilevel Inverter fed Induction Motor Drivernvsubbarao koppineni
This paper presents the Five level inverter with single DC source which is used to generate a five level output with two bridges and six switches and performance of three phase induction motor is analyzed when connected to PV array For this two identical dc sources of 50V each for two bridges in five levels using Multi level inverter and five level output is obtained by using a single DC source of 100V with six switches. A virtual DC source (charged capacitor acts as virtual DC source) is used for getting the output. The same technique is implemented for three-phase circuit i.e. by using single DC source. An asynchronous motor (three-phase) is connected as load and its performance characteristics are analyzed. And further the DC source is replaced by a renewable resource such as solar panels, fuel cell etc. and DC voltage is obtained. Performance characteristics of three-phase asynchronous motor are analyzed with PV array connected. The method can be easily extended to an m-level inverter.
This paper presents the detail circuitry modeling of single phase off-grid inverter for small standalone system applications. The entire model is developed in MATLAB/Simulink platform using circuitry model. This off grid inverter consists of a high frequency DC-DC step up converter cascaded with a full bridge PI control voltage source inverter using SPWM modulation with LC filter to produce sine wave output. This is a common design used in many small commercial off-grid inverter. This off-grid inverter model is capable to produce AC sinewave output voltage at 230 V 50 Hz up to 1 kW power from a 48 V DC lead acid battery source. The AC sine wave output waveform achieved a voltage Total Harmonic Distortion (THD) of less than 1 % which is almost a pure sine wave. The conversion efficiency performance of the off-grid inverter achieved more than 94 %. The performance of the model is validated by real commercial off-grid inverter. The performance validation experiment shows that the off-grid inverter Simulink model conversion efficiency and THD performance are comparable to the commercial off-grid inverter. This model contributes to assist small to medium standalone system load and battery sizing design with greater accuracy.
Here are the key characteristics of a good inverter:
- Sinusoidal output voltage waveform
- High gain
- Controllable output voltage and frequency
- Low power requirement for control circuitry
- Low cost
- Long working life
- Semiconductor devices with minimal switching and conduction losses
This document presents a comparison of different carrier-based pulse width modulation (PWM) strategies for controlling a five-level Z-source diode-clamped inverter. It first provides background on multilevel inverters and Z-source inverters. It then describes the operating principles of the Z-source inverter and equations for its output voltage. Simple boost control is presented as the control method. Three carrier-based PWM strategies - alternative phase opposition disposition, phase opposition disposition, and phase disposition - are described and their performance is evaluated through MATLAB simulations. The results show that alternative phase opposition disposition provides the highest output voltage boost but also the highest total harmonic distortion, while phase disposition has the lowest boost but also the lowest harmonic
IRJET- Comparative Analysis for Power Quality Improvenment of Cascaded an...IRJET Journal
This document compares the performance of cascaded and capacitor-clamped multilevel inverters. It analyzes the output voltage waveforms and total harmonic distortion of 3-level and 5-level configurations of each inverter topology. The cascaded inverter uses H-bridge cells with separate DC sources, while the capacitor-clamped inverter uses capacitors to transfer voltage between stages. Simulation results in MATLAB/Simulink show the voltage waveforms and fast Fourier transform analysis for each configuration. The cascaded inverter requires fewer components but separate DC sources, while the capacitor-clamped inverter requires voltage balancing of capacitors.
This paper proposes maximum boost control for 7-level z-source cascaded h-bridge inverter and their affiliation between voltage boost gain and modulation index. Z-source network avoids the usage of external dc-dc boost converter and improves output voltage with minimised harmonic content. Z-source network utilises distinctive LC impedance combination with 7-level cascaded inverter and it conquers the conventional voltage source inverter. The maximum boost controller furnishes voltage boost and maintain constant voltage stress across power switches, which provides better output voltage with variation of duty cycles. Single phase 7-level z-source cascaded inverter simulated using matlab/simulink.
A Novel Three Phase Multilevel Inverter with Single DC Link for Induction Mot...IJECEIAES
1) The document presents two configurations of a novel three-phase eleven-level multilevel inverter with a reduced number of switches for induction motor drive applications.
2) Configuration 1 uses separate DC sources for each phase, requiring 24 switches total. Configuration 2 uses a single common DC source for all three phases, also requiring 24 switches.
3) Both configurations are simulated in Matlab/Simulink. Results show the inverter produces a three-phase voltage of 600V peak-to-peak and supplies 50A to an induction motor, driving it at 1400rpm with 10N-m of torque.
This document describes the modeling and design of a five-level cascaded H-bridge multilevel inverter with a DC/DC boost converter. It begins with an introduction to multilevel inverters and their advantages over traditional two-level inverters. It then discusses the specific topology of a five-level cascaded H-bridge inverter and describes the operation and components of a DC/DC boost converter. Simulation results in MATLAB/Simulink are presented, showing the output voltage waveform both with and without filtering. The total harmonic distortion of the output is analyzed, showing less than 5% distortion. The conclusion is that this five-level inverter topology with boost converter provides high efficiency of 95% and improved power
Harmonic Analysis of Seven and Nine Level Cascade Multilevel Inverter using M...IAES-IJPEDS
The use of multilevel inverters has become popular in recent years for high- power applications. Multilevel Inverters are power converter systems composed by an array of power semiconductor sources that when properly connected and controlled can generate a multistep voltage waveform with variable and controllable frequency, phase and amplitude. This study deals with the comparison of a 7-level inverter with a 9-level inverter system; the voltage source inverters (VSI) are modelled and simulated using MATLAB Simulink and the results are presented. The test results verify the effectiveness of the proposed strategy in terms of computational efficiency as well as the capability of the inverter to produce very low distorted voltage with low-switching losses. This research aims to extend the knowledge about the performance of different clamped multilevel inverter through harmonic analysis. Simulations results validate up to the mark performance of the mentioned topologies.
BE-EEE-8th sem project report for the project titled "Asymmetrical Multilevel...MOHAMMED SAQIB
This document discusses asymmetrical multilevel inverters for producing higher output voltage levels. It introduces multilevel inverters and their advantages over traditional two-level inverters. The cascaded H-bridge topology requires fewer components and is suitable for high power applications. Asymmetric cascaded H-bridge topologies can produce more voltage levels using different DC source voltages. The document proposes a new asymmetric bidirectional converter topology that uses contradictory ratios of DC voltages to generate a higher number of output voltage levels using fewer switches. Simulation results will validate that this topology can achieve a seven-level output from two H-bridges with reduced total harmonic distortion.
Concept Kit 3-Phase AC Motor Drive Simulation (PSpice Version)Tsuyoshi Horigome
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The document describes the construction and operating principles of induction motors. It discusses:
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- The two main types of rotors: squirrel cage and wound rotor. Squirrel cage rotors are simpler and more rugged while wound rotors can be used to adjust torque-speed characteristics.
- Concepts like synchronous speed, slip, and rotor frequency. Slip is defined as the difference between synchronous and actual rotor speed.
- The per-phase equivalent circuit model of induction motors and how it is used to analyze power flow and calculate performance parameters like torque.
- DC generators and motors operate using the principle of electromagnetic induction. When a conductor moves through a magnetic field, an electromotive force (emf) is induced in the conductor.
- The basic components of a DC generator are a magnetic field (produced by poles and field windings) and a conductor (armature) that rotates within the magnetic field. This motion induces an emf in the armature.
- A commutator is used to convert the alternating current from the armature into direct current that can be supplied to a load. Brushes make contact with the commutator segments to carry the output current.
The document provides an overview of induction motors, including:
1. It describes the basic operating principle of induction motors, which induce a current in the rotor via electromagnetic induction from a rotating magnetic field in the stator.
2. It discusses different types of induction motors including single phase, three phase, squirrel cage, and slip ring rotors.
3. It provides some key formulas for induction motors relating supply frequency, pole pairs, synchronous speed, rotor speed, and slip.
1) Single phase induction motors use a split phase winding or capacitor start method to generate a rotating magnetic field for starting.
2) Synchronous motors operate at a constant synchronous speed and use a damper winding, pony motor, or DC motor method to reach synchronous speed before loading.
3) V curves show the relationship between armature current, field current, and excitation voltage in synchronous motors.
The induction motor operates on the principle of electromagnetic induction. It consists of two main parts - the stator and the rotor. The stator contains windings that generate a rotating magnetic field, acting as the primary. This rotating field induces currents in the rotor windings, which acts as the secondary. The rotor is then pushed to rotate at a slightly lower speed than the rotating field due to "slip."
This document outlines and describes the key components and operating principles of three-phase induction motors, which are widely used in industrial applications due to their continuous operation. It discusses the main types of electrical machines and induction motors, including squirrel cage and slip ring induction motors. The document explains the basic working principle of three-phase induction motors, involving the generation of a rotating magnetic field in the stator that induces current in the rotor. It also describes the main components of three-phase induction motors such as the frame, stator, rotor, and windings.
Analysis and hardware implementation of five level cascaded H Bridge inverterIJERA Editor
The cascaded multilevel inverter (CMLI) has gained much attention in recent years due to its advantages in high
voltage and high power with low harmonics applications. A standard cascaded multilevel inverter requires n DC
sources for 2n+1levels at the output, where n is the number of inverter stages. This paper presents a topology to
control cascaded multilevel inverter that is implemented with multiple DC sources to get 2"+1_ 1 levels. Without
using Pulse Width Modulation (PWM) technique, the firing circuit can be implemented using Microcontroller
which greatly reduces the Total Harmonic Distortion (THD) and switching losses. To develop the model of a
cascaded hybrid multilevel inverter, a simulation is done based on MATLAB/SIMULINK software and
hardware implementation was also done. Their integration makes the design and analysis of a hybrid multilevel
inverter more complete and detailed.
Multilevel DC Link Inverter with Reduced Switches and BatteriesIJPEDS-IAES
Multilevel inverters are the best solution for medium and high voltage power electronic drives. Because of its unique characteristic of synthesizing sinusoidal voltage with less harmonic contents using several DC sources. In a three phase multilevel inverter, each phase of a cascaded H-bridge inverter requires ‘n’ DC sources to obtain 2n + 1 output voltage levels. One particular disadvantage is that, it increases number of power semiconductor switches. To overcome this disadvantage a multilevel DC link inverter (MLDCLI) with reduced number of switches and batteries is proposed.
This document describes a fifteen-level inverter developed to transmit photovoltaic power from a solar array to the electric grid. The fifteen-level inverter uses a cascaded H-bridge configuration with low voltage MOSFET switches to reduce switching losses and harmonic distortion. It consists of a dual-buck converter to generate two DC voltages as inputs, and a full-bridge inverter to convert the output to a fifteen-level AC voltage synchronized to the grid. Simulation results show the fifteen-level output waveform is close to sinusoidal, reducing harmonic distortion below 0.5% compared to conventional two-level inverters. A controller regulates the current injected into the grid to be in phase. The system aims to provide
Analysis of 7-Level Cascaded & MLDCLI with Sinusoidal PWM & Modified Referenc...IJMTST Journal
This document compares the performance of a 7-level cascaded multilevel inverter and a 7-level multilevel DC link inverter (MLDCLI) using sinusoidal PWM and modified reference PWM control techniques. Simulation results show that the 7-level MLDCLI with modified reference PWM produces the highest fundamental output voltage with the lowest total harmonic distortion. The MLDCLI topology requires fewer switches and components than other multilevel inverter topologies as the number of voltage levels increases, making it advantageous for higher level designs.
Asymmetrical Cascaded Multi Level Inverter using Control Freedom Pulse width ...IAES-IJPEDS
In this paper, the suggested topologies are gained by cascading a full bridge inverter with dissimilar DC sources. This topology has several new patterns adopting the fixed switching frequency, multicarrier control freedom degree with mixture conceptions are established and simulated for the preferred three-phase cascaded multilevel inverter. In outstanding switching arrangement terminations, there are convinced degrees of freedom to produce the nine level AC output voltages with terminated switching positions for producing altered output voltages. These investigations focus on asymmetrical cascaded multilevel inverter engaging with carrier overlapping pulse width modulation (PWM) topologies. These topologies offer less amount of harmonics present in the output voltage and superior root mean square (RMS) values of the output voltages associated with the traditional sinusoidal pulse width modulation. This research studies carries with it MATLAB/SIMULINK based simulation and experimental results obtained using appropriated prototype to prove the validity of the proposed concept.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Comparative Analysis of Various Z-source Based Five Level Cascaded H-bridge M...journalBEEI
Z-source based multilevel inverters are the recent topologies as they have boosting ability and near sinusoidal output waveforms. This paper proposes different inverter topologies such as Z-source multilevel inverter and quasi Z-source multilevel inverter. This paper also deals with switched inductor and improved switched inductor topologies with quasi Z-network. The proposed switched inductor system reduces the voltage stresses caused by capacitors, power devices and diodes. In addition to multilevel inverter advantages, the proposed configuration employs Z-source inverter advantages. The Z-source inverter as compared to the traditional inverter is less costly, less complex, more efficient and more reliable. The performance of the proposed configurations is analysed by varying passive elements in impedance network and is simulated in MATLAB/SIMULINK. Phase disposition (PD) pulse width modulation (PWM) technique is applied on the proposed configurations and performance parameters are measured by the fast Fourier transform FFT analysis. The object of this paper is to develop an inverter which is used for variable speed drives with increase in output voltage by eliminating transformer and filter circuit. The performance is checked with standared parameter of the inverter.
With the purpose of rein in the high voltage of flexible power systems, renovation and
amendment of multi-level structures aimed at acquisition of high quality voltage is certainly required. In this
regard, robust topology must be occupied that encompass the maximum output voltage levels along with
minimum of switch number, of course, with taking into account of Peak Inverse Voltage (PIV). In this
paper, a neoteric high-performance multilevel cascaded inverter is suggested up to the problem of
repetitive output levels to be unraveled and also number of output voltage levels to be maximized. It has
been constructed by series-connected multilevel inverters blocks and three-level inverter. The simulation
results along with experimental results extracted by manufactured prototype have transparently approved
high efficiency of proposed inverter as well as its feasibility. Apart from above, new mathematical approach
has been presented to calculate and define the DC voltage sources magnitudes in asymmetric converter.
This document summarizes three topologies of cascaded H-bridge multilevel inverters: the existing topology, proposed topology I, and proposed topology II. The existing topology uses two DC sources per phase. Proposed topology I uses one DC source for all three phases and transformers. Proposed topology II also uses one DC source for all phases and reduces the number of switches compared to the other topologies. MATLAB simulations were performed and results were compared in terms of voltage THD and equipment requirements. The existing topology had the best performance based on FFT analysis, but proposed topology II is best in terms of cost and switching losses when considering single DC source topologies.
An Isolated 3 Phase Multilevel Inverter for PV Cell ApplicationsIJMTST Journal
This study presents a novel topology for multilevel inverters so called cascaded transformer inverter
(CTRSI). This topology consists of one DC source and several single-phase transformers. Each single-phase
transformers generates three levels with four semiconductor switches and only two switches for all
transformers alter the direction of single DC source. Whereas each single-phase transformers in conventional
cascaded transformer multilevel inverter includes more switches. Hence, CTRSI has the advantage of a
reduced number of components compared with conventional cascaded transformer multilevel inverter.
Simulation results carried out by MATLAB/SIMULINK. The results show that the proposed inverter topology
is able to reach high-quality output voltages. THD of output voltage is verified using FFT analysis tool
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This paper introduces a new topology of multilevel inverter, which is able to operate at high performance. This proposed circuit achieves requirements of reduced number of switches, gate-drive circuits, and high design flexibility. In most cases fifteen-level inverters need at least twelve switches. The proposed topology has only ten switches. The inverter has a quasi-sine output voltage, which is formed by level generator and polarity changer to produce the desired voltage and current waveforms. The detailed operation of the proposed inverter is explained. The theoretical analysis and design procedure are given. Simulation results are presented to confirm the analytical approach of the proposed circuit. A 15-level and 31-level multilevel inverters were designed and tested at 50 Hz.
The power electronics device which converts DC power to AC power at required output voltage and frequency level is known as inverter. Multilevel inverter is to synthesize a near sinusoidal voltage from several levels of dc voltages. In order to maintain the different voltage levels at appropriate intervals, the conduction time intervals of MOSFETS have been maintained by controlling the pulse width of gating pulses. In this paper single phase to three phase power conversion using PWM technique. The simulation is carried out in MATLAB/Simulink environment which demonstrate the feasibility of proposed scheme.
Performance Evaluation of Nine Level Modified CHB Multilevel Inverter for Var...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
Performance Analysis of Higher Order Cascaded H-Bridge Multilevel Invertersijtsrd
Cascade H-Bridge Multilevel Inverters are very popular and have many applications in electric utilities and for industrial drives. When these inverters are used for industrial drives directly, the Total Harmonic Distortion (THD) in the output voltage of inverters is very significant as the performance of drive depends very much on the quality of voltage applied to drive. A Multilevel Inverter in high power ratings improves the performance of the system by reducing Harmonics. This paper presents the simulation of single phase nine level and eleven level inverters. Detailed analysis of these inverters has been carried out and compared with different loads. PWM control strategy is applied to the switches at appropriate conducting angles with suitable delays. These different level inverters are realized by cascade H-Bridge in MATLAB/SIMULINK. The inverters with a large number of steps can generate high quality voltage waveforms. The THD depends on the switching angles for different units of Multilevel Inverters. Ms. Komal Shende | Dr. HariKumar Naidu | Prof. Vaishali Pawade"Performance Analysis of Higher Order Cascaded H-Bridge Multilevel Inverters" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-4 , June 2018, URL: http://www.ijtsrd.com/papers/ijtsrd14456.pdf http://www.ijtsrd.com/engineering/electrical-engineering/14456/performance-analysis-of-higher-order-cascaded-h-bridge-multilevel-inverters/ms-komal-shende
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
Simulation and analysis of multilevel inverter with reduced number of switchesIAEME Publication
This document summarizes a research paper that proposes a new multilevel inverter topology with reduced number of switches compared to conventional cascaded H-bridge multilevel inverters. The proposed topology is a five-level inverter that requires only six switches compared to eight switches in a conventional design. Simulation results show the performance of the new topology is validated using MATLAB/Simulink software. The paper also describes the operating modes and switching techniques used in the new multilevel inverter design, including phase disposition, alternative phase opposition disposition, and phase opposition disposition pulse width modulation strategies.
A Novel Three Phase Multi-string Multilevel Inverter with High DC-DC Closed o...rnvsubbarao koppineni
This document proposes and analyzes a novel three-phase multi-string multilevel inverter for photovoltaic systems. The inverter uses a high step-up DC-DC converter to boost and stabilize the output DC voltage from multiple renewable energy sources. It then uses a simplified multilevel inverter topology with only six switches instead of the eight switches used in conventional cascaded H-bridge multilevel inverters, reducing losses. Simulation and experimental results show the inverter provides improved output waveforms, lower harmonics, reduced size and cost compared to other topologies.
Total Harmonic Distortion Alleviation by using Shunt Active FilterIJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
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Design and Optimum Arrangement Of 3-phase Cascade Multilevel Inverter for Control of DTC Induction Motor
1. IOSR Journal of Electrical and Electronics Engineering (IOSR-JEEE)
e-ISSN: 2278-1676,p-ISSN: 2320-3331, Volume 6, Issue 6 (Jul. - Aug. 2013), PP 45-53
www.iosrjournals.org
www.iosrjournals.org 45 | Page
Design and Optimum Arrangement Of 3-phase Cascade
Multilevel Inverter for Control of DTC Induction Motor
V. Sharath Babu1
, M.Sriramulu2
, Md.Asif3
(EEE, Vardhaman College of Engineering (Autonomous), JNTU, Hyderabad, India)
Abstract : In present days the Multi level inverter increasing popularly especial in high power and high
voltage applications. The Multi level inverter having new set of features. When the level is increasing and
output become nearly sinusoidal. When the sinusoidal means the output voltage having less losses the more
levels of output voltage produces different methods is there the cascade H bridge is the most efficient method .In
my project cascade H bridge used to producing more levels of output voltages in cascade H bridge. In this
cascade H bridge two types of arrangement they are symmetrical and asymmetrical .In this cascade H bridge I
find out experimentally that the asymmetrical Multi level inverter is most efficient method than the symmetrical
method by using DTC technique. The DTC technique provides ripple losses and friction losses reduce. So the
induction motor having the most efficient .Here we are using IGBT switching and for the controlling purpose
uses the state vector modulation.
The cascade out experiment show that an asymmetrical configuration provides nearly sinusoidal voltages with
low distortion using less switching devices moreover torque ripples are reduced.
Keywords: State Vector Modulation (SVM),Direct Torque Control(DTC),Induction Motor(IM),Multi Level
Inveter (MLI)
I. Introduction
Multilevel voltage-source inverters are intensively studied for high-power applications and standard
drives for medium-voltage industrial applications have become available Solutions with a higher number of
output voltage levels have the capability to synthesize waveforms with a better harmonic spectrum and to limit
the motor winding insulation stress. However, their increasing number of devices tends to reduce the power
converter overall reliability and efficiency. On the other hand, solutions with a low number of levels either need
a rather large and expensive LC output filter to limit the motor winding insulation stress, or can only be used
with motors that do withstand such stress. The various voltage stages have been chosen after considering the
real-power contribution of the highest voltage stage. The maximum power supplied by highest voltage stage is
maintained below the load power.
One of the methods that have been used by a major multilevel inverter manufacturer is direct torque
control (DTC), which is recognized today as a high-performance control strategy for ac drives. Several authors
have addressed the problem of improving the behaviour of DTC ac motors, especially by reducing the torque
ripple. Different approaches have been proposed. Although these approaches are well suitable for the classical
two-levels inverter, their extension to a greater number of levels is not easy. Throughout this paper, a theoretical
background is used to design a strategy compatible with hybrid cascaded H-bridge multilevel inverter;
symmetrical and asymmetrical configuration are implemented and compared. Experimental results obtained for
an asymmetrical inverter-fed induction motor confirm the high dynamic performance of the used method,
presenting good performances and very low torque ripples. Multilevel power conversion has been receiving
increased attention recently, especially for high-power, high-voltage applications. To date, many inverter
topologies have been reported in the literature with particular interest focused on cascaded topology. The
conventional cascaded topology has many inherent benefits with one particular advantage being its modular
structure, which enables higher-level inverters to be easily implemented through the series connection of
identical H-bridges. This flexibility has resulted in its applications in medium-voltage industrial drives , electric
vehicles and the grid connection of photovoltaic-cell generation systems. A modified form of cascaded inverter
is the hybrid (binary,quasilinear or tri-nary) inverter . The hybrid inverter is basically a cascaded inverter in
which each of the cascaded H-bridges utilises different power devices and is supplied from an isolated DC
source of a different potential.The design intention of the hybrid inverter is to attain an optimal trade-off in the
selection of power devices in terms of switching frequency and voltage-sustaining capability, since the trends in
power semiconductor technology are that the voltage-blocking capability of fast-switching devices (e.g.
insulated-gate bipolar transistors) and the switching speed of high-voltage thyristor-based devices (e.g.
integrated- gate commutated thyristors) are limited. An optimized hybrid inverter is therefore more efficient as it
can generate the same number of output voltage levels using fewer power devices and DC sources as compared
with conventional cascaded inverter.
2. Design and Optimum Arrangement Of 3-phase Cascade Multilevel Inverter For Control of DTC
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II. Cascade H Bridge Operation
A single-phase structure of an m-level cascaded inverter is illustrated in. Each separate dc source
(SDCS) is connected to a single-phase full-bridge, or H-bridge, inverter. Each inverter level can generate three
different voltage outputs, +Vdc
, 0, and –Vdc
by connecting the dc source to the ac output by different
combinations of the four switches, S1
, S2
, S3
, and S4
. To obtain +Vdc
, switches S1
and S4
are turned on, whereas –
Vdc
can be obtained by turning on switches S2
and S3
. By turning on S1
and S2
or S3
and S4
, the output voltage is
0. The ac outputs of each of the different full-bridge inverter levels are connected in series such that the
synthesized voltage waveform is the sum of the inverter outputs. The number of output phase voltage levels m
in a cascade inverter is defined by m = 2s+1, where s is the number of separate dc sources. An example phase
voltage waveform for an 11-level cascaded H-bridge inverter with 5 SDCSs and 5 full bridges The phase
voltage
van
= va1
+ va2
+ va3
+ va4
+ va5
The cascaded H-bridge inverter consists of power conversion cells, each supplied by an isolated dc
source on the dc side, which can be obtained from batteries, fuel cells, or ultra capacitors and series-connected
on the ac side. The advantage of this topology is that the modulation, control, and protection requirements of
each bridge are modular. It should be pointed out that, unlike the diode-clamped and flying-capacitor topologies,
isolated dc sources are required for each cell in each phase.
Figure :- 3-phase three cells cascade H bridge
Figure : Symmetric multilevel inverter with seven-levels output voltage synthesis.
.
3. Design and Optimum Arrangement Of 3-phase Cascade Multilevel Inverter For Control of DTC
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The cascaded H-bridge inverter consists of power conversion cells, each supplied by an isolated dc
source on the dc side, which can be obtained from batteries, fuel cells, or ultracapacitors and series-connected
on the ac side. The advantage of this topology I that the modulation, control, and protection requirements of
each bridge are modular.
.
Figure:- Asymmetric multilevel inverter with eleven-levels output voltage synthesis.
It should be pointed out that, unlike the diode-clamped and flying-capacitor topologies, isolated dc
sources are required for each cell in each phase. Fig. 1 shows a three-phase topology of a cascade inverter with
isolated dc-voltage sources. An output phase-voltage waveform is obtained by summing the bridges output
voltages
vo (t) = vo,1 (t) + vo,2 (t) + · · · + vo,N (t) (1)
where N is the number of cascaded bridges. The inverter output voltage vo (t) may be determined from the
individual cells switching states
vo (t) =_N j=1(μj − 1) Vdc,j, μj = 0, 1, . . . . (2)
If all dc voltage sources in are equal to Vdc, the inverter is then known as a symmetric multilevel one.
The effective number of output voltage levels n in symmetric multilevel inverter is related to the cells number
by
n = 1+2 N (3)
For example, Fig. 2 illustrated typical waveforms of Fig. 1
multilevel inverter with two dc sources (five-levels output). The maximum output voltage Vo,Max is then
Vo,MAX = NVdc. (4)
To provide a large number of output levels without increasing the number of inverters, asymmetric
multilevel inverters can be used.
In it is proposed to chose the dc-voltages sources according to a geometric progression with a factor of
2 or 3. For N of such cascade inverters, one can achieve the The insulated-gate bipolar transistor or IGBT is a
three-terminal power semiconductor device, noted for high efficiency and fast switching. It switches electric
power in many modern appliances: electric cars, variable speed refrigerators, air-conditioners, and even stereo
systems with digital amplifiers. Since it is designed to rapidly turn on and off, amplifiers that use it often
synthesize complex waveforms with pulse width modulation and low-pass filters. The IGBT combines the
simple gate-drive characteristics of the MOSFETs with the high-current and low–saturation-voltage capability
of bipolar transistors by combining an isolated-gate FET for the control input, and a bipolar power transistor as a
switch, in a single device. The IGBT is used in medium- to high-power applications such as switched-mode
power supply, traction motor control and induction heating. Large IGBT modules typically consist of many
4. Design and Optimum Arrangement Of 3-phase Cascade Multilevel Inverter For Control of DTC
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devices in parallel and can have very high current handling capabilities in the order of hundreds of amps with
blocking voltages of 6,000 V. The IGBT is a fairly recent invention. The first-generation devices of the 1980s
and early 1990s were relatively slow in switching, and prone to failure through such modes as latch up and
secondary breakdown.
III. Direct Torque Control Of Multilevel Inverterfed Induction Machine:-
Direct Torque Control with Multilevel Inverter (DTC-MLI) has emerged recently in high dynamics AC
drives fields for induction machines or permanent magnet machines application. In this paper, a review on a
variety of techniques and concepts of direct torque control of multilevel inverter-fed induction machines is
presented. The techniques and concept involved are classified as follows: Look-up table hysteresis based DTC-
MLI, DTC-MLI with space vector modulation, predictive control strategy of DTC-MLI, hybrid modulation and
hybrid inverter strategy of DTC-MLI and DTC-MLI with fuzzy logic controller. From this review, the
properties of the discussed controller techniques together with advantages and disadvantages are presented.
Induction Machines (IMs) have been widely used in the industry due to the fact that it is maintenance
free, simple in terms of construction, reliable and rugged. In contrast to the commutation DC motors,induction
machines can be used in an explosive, corrosive or any harsh environment. This is because the latter has no
problem with spark and corrosion which is due to the commutator and the brushes as in the former. Despite
these advantages IM however, suffers from control problems when used in high performance Adjustable Speed
Drive (ASD) applications. Based on the commonly adopted space phasor dynamics model equations related to
the dynamics model
When a multilevel inverter is used in the DTC configuration to feed the IM, the number of available
voltage space vectors is increased proportionally to the voltage levels of the inverter. having this extra
flexibility in selecting the optimum voltage vector, a more precise control both torque and flux can be obtained.
To feed a three-phase IM, a three-phase multilevel inverter is required. The three-phase multilevel
inverter is composed of three multilevel inverter legs.There are three prominent multilevel inverter topologies:
Diode-clamped multilevel
Torque and Flux Estimation:
The stator flux vector an induction motor is related to the stator voltage and current vectors by
Maintaining vs constant over a sample time interval and neglecting the stator resistance, the integration
of (10) yields
Above Equation reveals that the stator flux vector is directly affected by variations on the stator voltage
vector. On the contrary, the influence of vs over the rotor flux is filtered by the rotor and stator leakage
inductance, and is, therefore, not relevant over a short-time horizon. Since the stator flux can be changed quickly
while the rotor flux rotates slower, the angle between both vectors θsr can be controlled directly by vs .
A graphical representation of the stator and rotor flux dynamic behavior is illustrated in Fig. The exact
relationship between stator and rotor flux shows that keeping the amplitude of φs constant will produce a
constant flux φr
5. Design and Optimum Arrangement Of 3-phase Cascade Multilevel Inverter For Control of DTC
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Fig. Influence of vs over φs during a simple interval Δt.
Voltage Vector Selection:
Fig. Possible voltage changes Δvks that can be applied from certain vks
Above Fig.illustrates one of the 127 voltage vectors generated by the inverter at instant t=k, denoted by
vks (central dot). The next voltage vector, to be applied to the load v(k+1)s , can be expressed by
v(k+1)s = vks +Δvks
where Δvks = {vi |i = 1, . . . , 6}. Each vector vi corresponds to one corner of the elemental hexagon
illustrated in gray and by the dashed line in above Fig. The task is to determine which v(k+1)s will correct the
torque and flux responses, knowing the actual voltage vector vks , the torque and flux errors ekφ and ekT , and
the stator flux vector position (sector determined by angle θs ). Note that the next voltage vector v(k+1)s applied
to the load will always be one of the six closest vectors to the previous vks ; this will soften the actuation effort
and reduce high dynamics in torque response due to possible large changes in the reference.
Table II summarizes vector selections for the different sectors and comparators output (desired φs and Te
corrections). To implement the DTC of the induction motor fed by a hybrid H-bridge multilevel inverter, one
should determine at each sampling period, the inverter switch logic states as a function of the torque and flux
instantaneous values for the selection of the space vector in the α–β frame. The proposed control algorithm was
divided into two major tasks, which are independent and executed in cascade.
Table II Voltage-Vector-Selection Lookup Table
1) First task: It aims at the control of the electromagnetic state of the induction motor. The torque and flux
instantaneous values, and their variations will be taken into account for the space vector selection in the α–β.
Once the space is chosen, the phase levels sequence can be selected. To ensure this task, one should detect the
space vector position in the α–β frame (Qk at sampling time k). The algorithm must then select the next position
Q(k+1) to be achieved before next sampling instant k + 1 (see Fig. 8) in order to reduce voltage steps
magnitude. Only one step displacement
6. Design and Optimum Arrangement Of 3-phase Cascade Multilevel Inverter For Control of DTC
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In the α–β frame is authorized per sampling period Ts . Hence, in the absence of inverter saturation,
Qk+1 must coincide with one of the six corners of the elementary hexagon centered at Qk . The same procedure
will be carried out at the next period in order to determine the next trajectory direction, yielding Qk+2, which in
turn will coincide with one of the six corners of the new elementary hexagon centered at Qk+1. In case of
inverter saturation (if Qk gives an unreachable point for Q(k+1), a trajectory correction is necessary (see Fig. 8).
In cases (2) and (3), the closest displacement direction is selected. Case (1) illustrates a particular
situation in which no switching should be performed, since the nearest reachable trajectory goesroughly toward
the opposite sense of the favored one given by the lookup table (see Table II).
2) Second task:
It exploits the degree of freedom related to the multilevel topology to choose the phase levels
sequence that synthesizes the voltage vector selected previously. There are several phase levels sequences that
are able to generate the same vector illustrated in Fig. 9; this degree of freedom can, therefore, be exploited to
reduce voltage steps magnitude according to one of the following criteria: a) minimize the commutation number
per period; b) distribute commutations for the three-phases per period; or c) choose a vector which minimizes
the homopolar voltage. This task allows losses and torque ripple minimization
.
Fig. Space vector and sequences of a seven-levels cascaded H-bridge inverter.
`Simulation circuites designs
Fig:- 3-phase power supply bridge circuite
2
2
1
1
A
B
C
Three-Phase Source
gm
CE
gm
CE
gm
CE
gm
CE
1
In1
7. Design and Optimum Arrangement Of 3-phase Cascade Multilevel Inverter For Control of DTC
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Fig:-3-phase 3-cell bridge circuites
Fig:- Block diagram Project outputs
Fig seven level cascade H Bridge symmetrical output waveform
3
c
2
b
1
a
In1
1
2
Subsystem8
In1
1
2
Subsystem7
In1
1
2
Subsystem6
In1
1
2
Subsystem5
In1
1
2
Subsystem4
In1
1
2
Subsystem3
In1
1
2
Subsystem2
In1
1
2
Subsystem1
In1
1
2
Subsystem
pulses
From24
Discrete,
Ts = 5e-005 s.
flux Table
Timer1
Timer
A
B
C
a
b
c
H Te
H Phi
Sector
Gates
Switching table
a
b
c
Subsystem9
Scope7
Scope5
Scope4
Scope3
Scope1
Scope
Relay2
Relay1
mod
Math
Function Lookup Table
1
s
Integrator
pulses
Goto8
isq
Goto7
isd
Goto6
phir_d
Goto5
phir_q
Goto4
phis_d
Goto3
Te
Goto2
phis_q
Goto1
Wr
Goto
-K-
Gain1
-K-
Gain
Wr
From9
Te
From6
Wr
From5
phis_q
From3
phis_d
From2
phis_d
From12
phis_q
From11
Te
From10
Iabcs
From1
Vabcs
From
In1Out1
Flux Hysteresisf(u)
Fcn1
f(u)
Fcn
PI
Discrete
PI Controller
2*pi
Constant
Tm
m
A
B
C
Add
<Rotor speed (wm)>
<Electromagnetic torque Te (N*m)><Electromagnetic torque Te (N*m)>
<Stator f lux phis_q (V s)><Stator f lux phis_q (V s)>
<Stator f lux phis_d (V s)>
<Rotor f lux phir_q (V s)>
<Rotor f lux phir_d (V s)>
<Stator current is_q (A)>
<Stator current is_d (A)>
8. Design and Optimum Arrangement Of 3-phase Cascade Multilevel Inverter For Control of DTC
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Fig eleven level cascade h bridge inverter torque waveform
Figure 1eleven level cascade h bridge inverter current waveform
Fig seven level cascade h bridge inverter current waveform
Fig Seven level cascade h bridge inverter stator flux wave form
Fig eleven level cascade h bridge inverter stator flux wave form
9. Design and Optimum Arrangement Of 3-phase Cascade Multilevel Inverter For Control of DTC
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IV. Conclusion
The paper dealt with a optimum arrangement for a cascade H bridge multi level inverter DTC
Induction motor. indeed symmetrical and asymmetrical arrangement of seven and eleven levels H bridge
inverters have been optimum arrangement in order to find with lower switching losses and optimized output
voltage quality the carried out experiments shows that an asymmetrical configuration provides nearly sinusoidal
voltages ith very low distortion using less switching devices. in addition torque ripples are greatly reduced
asymmetrical multi level inverter enables a DTC solution for high power induction motor drives not only due to
the higher voltage capability provided by multilevel inverter but mainly due to the reduced switching losses and
improved output voltage quality which provides sinusoidal current without filter
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