This paper proposes different types of modulation methods for the Diode Clamped Multi Level Inverter
(DCMLI). In this paper, a DCMLI is controlled with Sinusoidal PWM technique (SPWM), Third Harmonic
Injection PWM technique, Sixty degree PWM technique and Stepped wave technique with Sub harmonic
(SHPWM), Carrier Overlapping (CO), Phase shift (PS) , Variable frequency (VF) and the variation of
Total Harmonic Distortion (THD) in their outputs are observed and also chosen inverter is controlled by
SPWM technique, THI PWM technique, Sixty degree PWM and Stepped wave technique by varying the
modulation index. Simulation are performed using MATLAB-SIMULINK. It is observed that SHPWM
strategy provide output with relatively low distortion. It is observed that COPWM strategy provides higher
Vrms compared to other modulation strategies
Analysis and Implementation of Unipolar PWM Strategies for Three Phase Cascad...IJAAS Team
This paper presents unipolar pulse width modulation technique with sinusoidal sampling pulse width modulation are analyzed for three-phase five-level, seven-level, nine-level and eleven-level cascaded multi-level inverter. The unipolar PWM method offers a good opportunity for the realization of the Three-phase inverter control, it is better to use the unipolar PWM method with single carrier wave compared to two reference waves. In such case the motor harmonic losses will be considerably lower.The necessary calculations for generation of unipolar pulse width modulation strategies have presented in detail. The unipolar SPWM voltage switching scheme is selected in this paper because this method offers the advantages of effectively doubling the switching frequency of the inverter voltage. The cascaded multi level inverter fed induction motor is simulated and compared the total harmonic distroction for all level (five-level, seven-level, nine-level and elevel-level)of the inverter. Theoretical investigations were confirmed by the digital simulations using MATLAB/SIMULINK software.
This paper presents new modified space vector pulse width modulation techniques (Phase disposition-Space vector pulse width modulation, Alternative Phase Opposition disposition- Space vector pulse width modulation and Phase Opposition disposition-Space vector pulse width modulation) are analyzed for three-phase cascaded multi-level inverter fed induction motor from the point of view of the Phase voltages, line voltage, stator current,speed,torque and Total harmonic distortion.in the proposed modified technique the reference signals are generated by adding offset voltage to the reference phase voltages.This modified SVPWM technique does not involve region indentification,sector identification for switching vector determination as are required in the conventional multi level SVPWM technique,it is also reduces the computation time compared to the conventional space vector PWM technique.The necessary calculations for generation of new modified SVPWM for the modulation strategies have presented in detail. It is observed that the modified SVPWM modulation ensures excellent, close to optimized pulse distribution results and THD is compared to for five-level, seven-level, nine-level and eleven-level Cascaded H-Bride Multi-level Inverter fed to Induction motor. Theoretical investigations were confirmed by the digital simulations using MATLAB/SIMULINK software.
Performance Evaluation of a Three Phase Nine Level Inverter with Reduced Swit...Scientific Review
This paper presents a three phase nine level cascaded H-bridge (CHB) multilevel inverter with RL load. A sinusoidal and trapezoidal PWM method is used to achieve minimum total harmonics distortion (THD) in the output current of multilevel inverters. The analysis of the output current harmonics is carried out and compared with the seven level conventional cascaded H-bridge inverters. The proposed inverter is verified through simulation and the simulation results are compared with the conventional multilevel inverter. From the result the proposed inverter offers much less total harmonic distortion.
Performance Evaluation of a Three Phase Nine Level Inverter with Reduced Sw...Scientific Review SR
This paper presents a three phase nine level cascaded H-bridge (CHB) multilevel inverter with RL load. A sinusoidal and trapezoidal PWM method is used to achieve minimum total harmonics distortion (THD) in the output current of multilevel inverters. The analysis of the output current harmonics is carried out and compared with the seven level conventional cascaded H-bridge inverters. The proposed inverter is verified through
simulation and the simulation results are compared with the conventional multilevel inverter. From the result the
proposed inverter offers much less total harmonic distortion
This is collection of First Dozen of papers published by Mohd Esa
Mohd Esa, completed M.E. (Power Electronics systems) from Muffakham Jah College of Engineering and Technology, Banjarahills, Hyderabad in 2018. He received his B.E degree from Osmania University, Hyderabad. He was awarded gold medal twice for standing first in B.E. III/IV and B.E. IV/IV from Matrusri Engineering College, Sayeedabad, Hyderabad. He has published 12 research papers in various journals and conferences. He is Member of International Association of Engineers (IAENG), Hong Kong. His research of interests includes Multi level inverters and Multipliers. He is currently working as Junior Research Fellow.
Analysis and Implementation of Unipolar PWM Strategies for Three Phase Cascad...IJAAS Team
This paper presents unipolar pulse width modulation technique with sinusoidal sampling pulse width modulation are analyzed for three-phase five-level, seven-level, nine-level and eleven-level cascaded multi-level inverter. The unipolar PWM method offers a good opportunity for the realization of the Three-phase inverter control, it is better to use the unipolar PWM method with single carrier wave compared to two reference waves. In such case the motor harmonic losses will be considerably lower.The necessary calculations for generation of unipolar pulse width modulation strategies have presented in detail. The unipolar SPWM voltage switching scheme is selected in this paper because this method offers the advantages of effectively doubling the switching frequency of the inverter voltage. The cascaded multi level inverter fed induction motor is simulated and compared the total harmonic distroction for all level (five-level, seven-level, nine-level and elevel-level)of the inverter. Theoretical investigations were confirmed by the digital simulations using MATLAB/SIMULINK software.
This paper presents new modified space vector pulse width modulation techniques (Phase disposition-Space vector pulse width modulation, Alternative Phase Opposition disposition- Space vector pulse width modulation and Phase Opposition disposition-Space vector pulse width modulation) are analyzed for three-phase cascaded multi-level inverter fed induction motor from the point of view of the Phase voltages, line voltage, stator current,speed,torque and Total harmonic distortion.in the proposed modified technique the reference signals are generated by adding offset voltage to the reference phase voltages.This modified SVPWM technique does not involve region indentification,sector identification for switching vector determination as are required in the conventional multi level SVPWM technique,it is also reduces the computation time compared to the conventional space vector PWM technique.The necessary calculations for generation of new modified SVPWM for the modulation strategies have presented in detail. It is observed that the modified SVPWM modulation ensures excellent, close to optimized pulse distribution results and THD is compared to for five-level, seven-level, nine-level and eleven-level Cascaded H-Bride Multi-level Inverter fed to Induction motor. Theoretical investigations were confirmed by the digital simulations using MATLAB/SIMULINK software.
Performance Evaluation of a Three Phase Nine Level Inverter with Reduced Swit...Scientific Review
This paper presents a three phase nine level cascaded H-bridge (CHB) multilevel inverter with RL load. A sinusoidal and trapezoidal PWM method is used to achieve minimum total harmonics distortion (THD) in the output current of multilevel inverters. The analysis of the output current harmonics is carried out and compared with the seven level conventional cascaded H-bridge inverters. The proposed inverter is verified through simulation and the simulation results are compared with the conventional multilevel inverter. From the result the proposed inverter offers much less total harmonic distortion.
Performance Evaluation of a Three Phase Nine Level Inverter with Reduced Sw...Scientific Review SR
This paper presents a three phase nine level cascaded H-bridge (CHB) multilevel inverter with RL load. A sinusoidal and trapezoidal PWM method is used to achieve minimum total harmonics distortion (THD) in the output current of multilevel inverters. The analysis of the output current harmonics is carried out and compared with the seven level conventional cascaded H-bridge inverters. The proposed inverter is verified through
simulation and the simulation results are compared with the conventional multilevel inverter. From the result the
proposed inverter offers much less total harmonic distortion
This is collection of First Dozen of papers published by Mohd Esa
Mohd Esa, completed M.E. (Power Electronics systems) from Muffakham Jah College of Engineering and Technology, Banjarahills, Hyderabad in 2018. He received his B.E degree from Osmania University, Hyderabad. He was awarded gold medal twice for standing first in B.E. III/IV and B.E. IV/IV from Matrusri Engineering College, Sayeedabad, Hyderabad. He has published 12 research papers in various journals and conferences. He is Member of International Association of Engineers (IAENG), Hong Kong. His research of interests includes Multi level inverters and Multipliers. He is currently working as Junior Research Fellow.
ANALYSIS AND IMPLEMENTATION OF FPGA CONTROL OF ASYMMETRIC MULTILEVEL INVERTER...IJAMSE Journal
This paper presents an Asymmetric Multilevel Inverter (AMLI) with reduced number of switches for fuel
cells and suitable for high voltage and high power applications. Among the several types of multilevel
inverter, AMLI is a suitable choice to generate the higher number of output voltage levels with fewer
switches and sources. A novel hybrid modulation strategy based on Variable Amplitude Phase Opposition
and Disposition (VAPOD) is implemented using FPGA for AMLI which is powered by Proton Exchange
Membrane Fuel Cell (PEMFC). The operation of the proposed AMLI is verified with simulation and
experimental results.
Analysis of Binary DC Source Reduced Switch 7-level InverterIAES-IJPEDS
This paper proposes a binary DC source reduced switch 7-level inverter. Binary DC source reduced switch inverter is triggered by the Unipolar PWM strategy having sinusoidal and trapezoidal reference with triangular carriers. These pulse width modulating (PWM) strategies include phase disposition (PD), alternate phase opposition disposition (APOD), carrier overlapping (CO). Performance factors like total harmonic distortion (THD), VRMS (fundamental) and crest factor are evaluated for various modulation indices. Simulations were performed using MATLAB-SIMULINK. It is observed that UPDPWM strategy with trapezoidal reference provides output with relatively low distortion and UCOPWM strategy with trapezoidal reference provides relatively higher fundamental RMS output voltage.
THD analysis of SPWM & THPWM Controlled Three phase Voltage Source InverterMOHD ABDUL MUQEEM NAWAZ
The aim of this paper is to determine the Total harmonic distortion (THD) of three phase voltage source inverter (VSI) fed R-L load. The modulation Techniques used is Sinusoidal pulse width modulation (SPWM) and third harmonic pulse width modulation (THPWM). The Carrier frequency is varied to analyze its effect on Current THD and Voltage THD.This paper also presents the comparison of SPWM and THPWM controlled Inverter in terms of THD. The simulation result shows THPWM has better performance when compared to SPWM. The simulation of circuit is done by using MATLAB/Simulink.
THD analysis of SPWM & THPWM Controlled Three phase Voltage Source InverterMohd Esa
The aim of this paper is to determine the Total harmonic distortion (THD) of three phase voltage source inverter (VSI) fed R-L load. The modulation Techniques used is Sinusoidal pulse width modulation (SPWM) and third harmonic pulse width modulation (THPWM). The Carrier frequency is varied to analyze its effect on Current THD and Voltage THD.This paper also presents the comparison of SPWM and THPWM controlled Inverter in terms of THD. The simulation result shows THPWM has better performance when compared to SPWM. The simulation of circuit is done by using MATLAB/Simulink.
A Novel Hybrid Negative Half Cycle Biased Modulation Scheme for Cascaded Mult...IJPEDS-IAES
This paper proposes a new Modified hybrid modulation scheme for cascaded multilevel inverter. The proposed method employs novel single carrier sinusoidal pulse width modulation with its negative cycle biased (HNHCBM) for reducing switching losses when compared to other sinusoidal modulation methods using a hybrid scheme. This scheme is a derivative of various single carrier sinusoidal pulse width modulation scheme and main advantages are reduced harmonics, enhanced output voltage, reduced power loss in the series cells and ease of implementation. The simulation results are analysed with matlab/simulink and compared with experimental results obtained using 5-level inverter and the results are summarized.
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.
Harmonic Analysis of Three level Flying Capacitor InverterMohd Esa
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.
The Operating Improvement of the Supply Source and the Optimization of PWM Co...IJPEDS-IAES
In this paper the operating improvement of the supply source and the
optimization of PWM control are proposed. A comparison (based on the
better operating in terms of input voltage) between the multilevel inverters
(NPC multilevel inverter and H bridge inverter) is studied. Then two control
strategies (the SPWM and the suboptimal PWM) are applied to the multilevel
inverter which has the better voltage performance. At last a comparison
between these two control techniques based on two essential points, the THD
and the output voltage value. A comparison between our results and results
taken from literature is also presented in this paper. Simulations are carried
out using PSIM environment.
Common Mode Voltage reduction in Diode Clamped MLI using Alternative Phase Op...Mohd Esa
The main objective of this paper is to reduce the Common Mode Voltage (CMV) in the Diode Clamped Multilevel Inverter (DCMLI).Three phase Y-connected RL load is connected to DCMLI. The common mode voltage exists between neutral point of Y-connected load and system ground.CMV causes premature failure of bearings of induction motor and is essential to reduce. In this paper, Alternative Phase Opposition Disposition SPWM technique is used to reduce common mode voltage. Two level, five level, seven level and nine level DCMLI are compared in terms of THD and CMV.The effect of a passive LC filter on THD was studied. The simulation of circuit is carried out by using MATLAB/Simulink. Simulation result portrays reduction in THD and CMV by using APOD-SPWM controlled higher level Inverters.
Simulation Investigation of SPWM, THIPWM and SVPWM Techniques for Three Phase...IJPEDS-IAES
Pulse width modulation (PWM) technique is one of the vital issues for power electronic circuit control. A number of Pulse width modulation (PWM) techniques are increasingly applied in many new industrial applications that require superior performance. The most widely applied PWM technique for three-phase voltage source inverters are Sine Pulse Width Modulation (SPWM), Third Harmonic Injection Pulse Width Modulation (THIPWM) and Space Vector Pulse Width Modulation (SVPWM). SPWM is the most simple modulation technique that can realize easily in analog circuit. However, it has some drawbacks such as higher total harmonic distortion (THD), lower switching frequency and not capable in over modulation region. THIPWM and SVPWM both provide better THD compared to SPWM. SVPWM shows lower THD in over modulation region and in high frequency application compared to THIPWM. These three techniques are discussed, analyzed and compared in terms of modulation index, switching frequency and inverter input voltage in this paper. The modeling and simulation for all PWM techniques have been done by using MATLAB/SIMULINK and Origin 6.1. From the simulation results, SVPWM shows the best performance and meet IEEE 519 standard of current harmonics level.
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
Alternating current (AC) electrical drives mainly require smaller current (or torque) ripples and lower total harmonic distortion (THD) of voltage for excellent drive performances. Normally, in practice, to achieve these requirements, the inverter needs to be operated at high switching frequency. By operating at high switching frequency, the size of filter can be reduced. However, the inverter which oftenly employs insulated gate bipolar transistor (IGBT) for high power applications cannot be operated at high switching frequency. This is because, the IGBT switching frequency cannot be operated above 50 kHz due to its thermal restrictions. This paper proposes an alternate switching strategy to enable the use of IGBT for operating the inverter at high switching frequency to improve THD performances. In this strategy, each IGBT in a group of switches in the modified inverter circuit will operate the switching frequency at one-fourth of the inverter switching frequency. The alternate switching is implemented using simple analog and digital integrated circuits.
Multilevel Inverter using SPWM Technique for AC Power SupplyIJERA Editor
This paper presents two multilevel inverter for AC power supply. The cascaded H bridge topology of multilevel inverter is implemented .The control strategy has been design using SPWM technique. The operation of multilevel inverter is analyzed. The output has controlled and reduction in harmonic and THD. The simulation model has been built in matlab simulink and results are observed.
Constant Frequency Torque Controller for DTC with Multilevel Inverter of Indu...IJPEDS-IAES
Direct Torque Control using multilevel inverter (DTC-MLI) with hysteresis
controller suffers from high torque and flux ripple and variable switching
frequency. In this paper, a constant frequency torque controller is proposed to
enhance the DTC-MLI performance. The operational concepts of the
constant switching frequency torque controller of a DTC-MLI system
followed by the simulation results and analysis are presented. The proposed
system significantly improves the DTC drive in terms of dynamic
performance, smaller torque and flux ripple, and retains a constant switching
frequency.
CMV analysis of 5-level Cascaded H-Bridge MLI with equal and unequal DC sourc...Mohd Esa
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.
CMV analysis of 5 level Cascaded H Bridge MLI with equal and unequal DC sourc...MOHD ABDUL MUQEEM NAWAZ
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.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
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ANALYSIS AND IMPLEMENTATION OF FPGA CONTROL OF ASYMMETRIC MULTILEVEL INVERTER...IJAMSE Journal
This paper presents an Asymmetric Multilevel Inverter (AMLI) with reduced number of switches for fuel
cells and suitable for high voltage and high power applications. Among the several types of multilevel
inverter, AMLI is a suitable choice to generate the higher number of output voltage levels with fewer
switches and sources. A novel hybrid modulation strategy based on Variable Amplitude Phase Opposition
and Disposition (VAPOD) is implemented using FPGA for AMLI which is powered by Proton Exchange
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Analysis of Binary DC Source Reduced Switch 7-level InverterIAES-IJPEDS
This paper proposes a binary DC source reduced switch 7-level inverter. Binary DC source reduced switch inverter is triggered by the Unipolar PWM strategy having sinusoidal and trapezoidal reference with triangular carriers. These pulse width modulating (PWM) strategies include phase disposition (PD), alternate phase opposition disposition (APOD), carrier overlapping (CO). Performance factors like total harmonic distortion (THD), VRMS (fundamental) and crest factor are evaluated for various modulation indices. Simulations were performed using MATLAB-SIMULINK. It is observed that UPDPWM strategy with trapezoidal reference provides output with relatively low distortion and UCOPWM strategy with trapezoidal reference provides relatively higher fundamental RMS output voltage.
THD analysis of SPWM & THPWM Controlled Three phase Voltage Source InverterMOHD ABDUL MUQEEM NAWAZ
The aim of this paper is to determine the Total harmonic distortion (THD) of three phase voltage source inverter (VSI) fed R-L load. The modulation Techniques used is Sinusoidal pulse width modulation (SPWM) and third harmonic pulse width modulation (THPWM). The Carrier frequency is varied to analyze its effect on Current THD and Voltage THD.This paper also presents the comparison of SPWM and THPWM controlled Inverter in terms of THD. The simulation result shows THPWM has better performance when compared to SPWM. The simulation of circuit is done by using MATLAB/Simulink.
THD analysis of SPWM & THPWM Controlled Three phase Voltage Source InverterMohd Esa
The aim of this paper is to determine the Total harmonic distortion (THD) of three phase voltage source inverter (VSI) fed R-L load. The modulation Techniques used is Sinusoidal pulse width modulation (SPWM) and third harmonic pulse width modulation (THPWM). The Carrier frequency is varied to analyze its effect on Current THD and Voltage THD.This paper also presents the comparison of SPWM and THPWM controlled Inverter in terms of THD. The simulation result shows THPWM has better performance when compared to SPWM. The simulation of circuit is done by using MATLAB/Simulink.
A Novel Hybrid Negative Half Cycle Biased Modulation Scheme for Cascaded Mult...IJPEDS-IAES
This paper proposes a new Modified hybrid modulation scheme for cascaded multilevel inverter. The proposed method employs novel single carrier sinusoidal pulse width modulation with its negative cycle biased (HNHCBM) for reducing switching losses when compared to other sinusoidal modulation methods using a hybrid scheme. This scheme is a derivative of various single carrier sinusoidal pulse width modulation scheme and main advantages are reduced harmonics, enhanced output voltage, reduced power loss in the series cells and ease of implementation. The simulation results are analysed with matlab/simulink and compared with experimental results obtained using 5-level inverter and the results are summarized.
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.
Harmonic Analysis of Three level Flying Capacitor InverterMohd Esa
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.
The Operating Improvement of the Supply Source and the Optimization of PWM Co...IJPEDS-IAES
In this paper the operating improvement of the supply source and the
optimization of PWM control are proposed. A comparison (based on the
better operating in terms of input voltage) between the multilevel inverters
(NPC multilevel inverter and H bridge inverter) is studied. Then two control
strategies (the SPWM and the suboptimal PWM) are applied to the multilevel
inverter which has the better voltage performance. At last a comparison
between these two control techniques based on two essential points, the THD
and the output voltage value. A comparison between our results and results
taken from literature is also presented in this paper. Simulations are carried
out using PSIM environment.
Common Mode Voltage reduction in Diode Clamped MLI using Alternative Phase Op...Mohd Esa
The main objective of this paper is to reduce the Common Mode Voltage (CMV) in the Diode Clamped Multilevel Inverter (DCMLI).Three phase Y-connected RL load is connected to DCMLI. The common mode voltage exists between neutral point of Y-connected load and system ground.CMV causes premature failure of bearings of induction motor and is essential to reduce. In this paper, Alternative Phase Opposition Disposition SPWM technique is used to reduce common mode voltage. Two level, five level, seven level and nine level DCMLI are compared in terms of THD and CMV.The effect of a passive LC filter on THD was studied. The simulation of circuit is carried out by using MATLAB/Simulink. Simulation result portrays reduction in THD and CMV by using APOD-SPWM controlled higher level Inverters.
Simulation Investigation of SPWM, THIPWM and SVPWM Techniques for Three Phase...IJPEDS-IAES
Pulse width modulation (PWM) technique is one of the vital issues for power electronic circuit control. A number of Pulse width modulation (PWM) techniques are increasingly applied in many new industrial applications that require superior performance. The most widely applied PWM technique for three-phase voltage source inverters are Sine Pulse Width Modulation (SPWM), Third Harmonic Injection Pulse Width Modulation (THIPWM) and Space Vector Pulse Width Modulation (SVPWM). SPWM is the most simple modulation technique that can realize easily in analog circuit. However, it has some drawbacks such as higher total harmonic distortion (THD), lower switching frequency and not capable in over modulation region. THIPWM and SVPWM both provide better THD compared to SPWM. SVPWM shows lower THD in over modulation region and in high frequency application compared to THIPWM. These three techniques are discussed, analyzed and compared in terms of modulation index, switching frequency and inverter input voltage in this paper. The modeling and simulation for all PWM techniques have been done by using MATLAB/SIMULINK and Origin 6.1. From the simulation results, SVPWM shows the best performance and meet IEEE 519 standard of current harmonics level.
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
Alternating current (AC) electrical drives mainly require smaller current (or torque) ripples and lower total harmonic distortion (THD) of voltage for excellent drive performances. Normally, in practice, to achieve these requirements, the inverter needs to be operated at high switching frequency. By operating at high switching frequency, the size of filter can be reduced. However, the inverter which oftenly employs insulated gate bipolar transistor (IGBT) for high power applications cannot be operated at high switching frequency. This is because, the IGBT switching frequency cannot be operated above 50 kHz due to its thermal restrictions. This paper proposes an alternate switching strategy to enable the use of IGBT for operating the inverter at high switching frequency to improve THD performances. In this strategy, each IGBT in a group of switches in the modified inverter circuit will operate the switching frequency at one-fourth of the inverter switching frequency. The alternate switching is implemented using simple analog and digital integrated circuits.
Multilevel Inverter using SPWM Technique for AC Power SupplyIJERA Editor
This paper presents two multilevel inverter for AC power supply. The cascaded H bridge topology of multilevel inverter is implemented .The control strategy has been design using SPWM technique. The operation of multilevel inverter is analyzed. The output has controlled and reduction in harmonic and THD. The simulation model has been built in matlab simulink and results are observed.
Constant Frequency Torque Controller for DTC with Multilevel Inverter of Indu...IJPEDS-IAES
Direct Torque Control using multilevel inverter (DTC-MLI) with hysteresis
controller suffers from high torque and flux ripple and variable switching
frequency. In this paper, a constant frequency torque controller is proposed to
enhance the DTC-MLI performance. The operational concepts of the
constant switching frequency torque controller of a DTC-MLI system
followed by the simulation results and analysis are presented. The proposed
system significantly improves the DTC drive in terms of dynamic
performance, smaller torque and flux ripple, and retains a constant switching
frequency.
CMV analysis of 5-level Cascaded H-Bridge MLI with equal and unequal DC sourc...Mohd Esa
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.
CMV analysis of 5 level Cascaded H Bridge MLI with equal and unequal DC sourc...MOHD ABDUL MUQEEM NAWAZ
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.
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PERFORMANCE EVALUATION ON UNIPOLAR PWM STRATEGIES FOR THREE PHASE DIODE CLAMPED MULTILEVEL INVERTER
1. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
DOI : 10.14810/ijscmc.2015.4202 11
PERFORMANCE EVALUATION ON UNIPOLAR PWM
STRATEGIES FOR THREE PHASE DIODE CLAMPED
MULTILEVEL INVERTER
C.R.Balamurugan1
S.P.Natarajan2
R.Bensraj3
and T.S.Anandhi4
1
Department of EEE, Arunai Engineering College, Tiruvannamalai
2,3,4
Annamalai University, Chidambaram, Tamilnadu
ABSTRACT
This paper proposes different types of modulation methods for the Diode Clamped Multi Level Inverter
(DCMLI). In this paper, a DCMLI is controlled with Sinusoidal PWM technique (SPWM), Third Harmonic
Injection PWM technique, Sixty degree PWM technique and Stepped wave technique with Sub harmonic
(SHPWM), Carrier Overlapping (CO), Phase shift (PS) , Variable frequency (VF) and the variation of
Total Harmonic Distortion (THD) in their outputs are observed and also chosen inverter is controlled by
SPWM technique, THI PWM technique, Sixty degree PWM and Stepped wave technique by varying the
modulation index. Simulation are performed using MATLAB-SIMULINK. It is observed that SHPWM
strategy provide output with relatively low distortion. It is observed that COPWM strategy provides higher
Vrms compared to other modulation strategies.
KEYWORDS
THD, Stepped, THIPWM, 60 degree PWM, unipolar.
1.INTRODUCTION
MLIs easily produce high-power, high-voltage output with the multilevel structure because of the
way the device voltage stresses are controlled in the structure. Babaei et al [1] proposed
a inverter contained of a series connection of the proposed basic unit and is able to only generate
positive levels at the output. Selvamuthukumaran et al[2] also proposed a H-MCPWM strategy
ensures low leakage current in the transformer less PV inverter system with simplicity in
implementation of the modulation strategy using lesser number of carriers. Edpuganti et al [3]
suggested to operate a multilevel inverter for motor drive using SOP strategy. Kai-Ming Tsang et
al [4] proposed a topology approach enables multilevel output to be realized by a few cascaded
H-bridges and a three-leg inverter using lower number of power switches. Babaei et al [5]
suggested a topology which requires lesser number of power switches and dc voltage sources.
Odeh et al [6] developed a multicarrier, phase disposition PWM technique is applied to generate
the gating signals for the power switches. Young et al. [7] discusses a combination of batteries
can be controlled according to the batteries' voltages to implement the battery-balancing function.
Gupta et al [8] made a synthesis of multilevel waveform using minimum number of power
switches as compared to the classical topologies. Cougo et al [9] suggest pulse width modulation
technique based on carriers' disposition and on zero sequence injection is analyzed for parallel
multilevel inverters. Zixin et al. [10] discuses level of the output voltage is only half of the dc-link
voltage in all conditions, leading to much reduced dv/dt. Palanivel et al [11] observed this
topologies of multilevel inverter have several advantages such as high output voltage, lower
2. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
12
electromagnetic interference, lower THD. Khoucha et al [12] developed a symmetrical and
asymmetrical arrangements of five- and seven-level H-bridge inverters are compared in order to
determine optimum arrangement with lower switching losses and optimized output voltage
quality. Jing zhao et al [13] suggested minimum number of devices switching on or off within
broad modulation index range, accordingly reducing switching losses and reduce the amplitude of
lower harmonics. Naumanem et al [14] proposed pulsed inverter voltage and the impedance
mismatch between the cable and the motor cause an oscillating overvoltage in the motor
terminals.
2. MULTILEVEL INVERTER
The MLIs synthesize a near sinusoidal voltage from several DC voltage sources. A diode clamped
multilevel (m-level) inverter typically consists of (m-1) capacitors on the bus and produces m
levels on the phase voltage. Fig.1 shows three phase five level diode clamped multilevel inverter.
The numbering order of the switches for R-phase is Sa1, Sa2, Sa3, Sa4, Sa1’, Sa2’,Sa3’ and Sa4’.
Figure. 1 Power Circuit for 3Φ DCMLI
The gate signals for chosen five level diode clamped inverter are simulated using MATLAB-
SIMULINK. The control gate signals are developed and checked. Fig. 2 shows a sample
SIMULINK model.
Figure. 2 Sample control signal generation SIMULINK
3. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
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3. UNIPOLAR MULTICARRIER PWM STRATEGIES
This paper presents four types of unipolar PWM strategies.
3.1. Unipolar Sub Harmonic PWM Strategies
The principle of the USHPWM strategy is similar to bipolar PDPWM strategy.
ma=Am/n *Ac
Figure. 3 Sample modulating and Carrier signal for USHPWM technique ( ma=0.8 , mf=40 )
3.2. Unipolar Phase Shift (PSPWM) Strategy
The UPSPWM is same as bipolar PSPWM strategy.
ma=Am/Ac
Figure. 4 Sample modulating and Carrier signal for UPSPWM strategy ( ma=0.8 , mf=40 )
3.3. Unipolar Carrier Overlapping (COPWM) Strategy
The UCOPWM is same as bipolar COPWM.
4. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
14
Figure. 5 Sample modulating and carrier signals for UCOPWM strategy ( ma=0.8 , mf=40 )
3.4. Unipolar Variable Frequency (VFPWM) Strategy
The UVFPWM is same as bipolar VFPWM.
Figure. 6 Sample modulating and carrier signals for UVFPWM strategy ( ma=0.8 , mf=40 )
4. THIRD HARMONIC INJECTION METHOD
The third-harmonic is a advanced modulation technique. By using this signal as reference the root
mean square value of voltage will increase by 15.5 %. But the THD will be increased compared
to sinusoidal signal. THIPWM technique is shown in Figs. 7 to 10.
Figure. 7 Modulating and Carrier signal for UTHIPWM strategy ( ma=0.8 , mf=40 )
5. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
15
Figure. 8 Modulating and Carrier signal for UPSPWM strategy ( ma=0.8 , mf=40 )
Figure. 9 Modulating and Carrier signal for UCOPWM strategy ( ma=0.8 , mf=40 )
Figure. 10 Modulating and Carrier signal for UVFPWM strategy( ma=0.8 , mf=40 )
5. 60 DEGREE PWM METHOD
This method is a advanced modulation technique. This type of reference is also called as
trapezoidal reference. This type of reference also increase the fundamental voltage. 60 degree
PWM technique is shown in Figs. 11 to 14.
6. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
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Figure. 11 Modulating and Carrier signal for USHPWM strategy ( ma=0.8 , mf=40 )
Figure. 12 Modulating and Carrier signal for UPSPWM strategy ( ma=0.8 , mf=40 )
Figure. 13 Modulating and Carrier signal for UCOPWM strategy ( ma=0.8 , mf=40 )
Figure. 14 Modulating and Carrier signal for UVFPWM strategy ( ma=0.8 , mf=40 )
7. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
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6. STEPPED MODULATION
The stepped wave is a advanced modulation reference. This reference is used to increase the
fundamental RMS voltage. Stepped wave PWM techniques is as shown in Figs. 15 to 18.
Figure. 15 Modulating and Carrier signal for USHPWM strategy ( ma=0.8 , mf=40 )
Figure. 16 Modulating and Carrier signal for UPSPWM strategy ( ma=0.8 , mf=40 )
Figure. 17 Modulating and Carrier signal for UCOPWM strategy ( ma=0.8 , mf=40 )
8. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
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Figure. 18 Modulating and Carrier signal for UVFPWM strategy ( ma=0.8 , mf=40 )
7. SIMULATION RESULT
Switching signals for DCMLI are developed using unipolar PWM techniques discussed
previously. Simulation and hardware results are taken for different values of ma ranging from 0.6
– 1. The Hardware and simulation parameters are : VDC =880V, mf =40, fc = 2000Hz, fm = 50Hz
and R (load) = 100 ohms.
Figure. 19 Output voltage generated by USHPWM strategy for sine. Reference
Figure. 20 FFT plot for output voltage of USHPWM strategy for sine. reference
9. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
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Figure. 21 Output voltage generated by UCOPWM strategy for sine. reference
Figure. 22 FFT plot for output voltage of UCOPWM strategy for sine. reference
Figure. 23 Output voltage generated by UPSPWM strategy for sine. reference
Figure. 24 FFT plot for output voltage of UPSPWM strategy for sine. reference
10. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
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Figure. 25 Output voltage generated by UVFPWM strategy for sine. reference
Figure. 26 FFT plot for output voltage of UVFPWM strategy for sine. reference
Figure. 27 Output voltage generated by USHPWM strategy for THI reference
Figure. 28 FFT plot for output voltage of USHPWM strategy for THI reference
11. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
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Figure. 29 Output voltage generated by UCOPWM strategy for THI reference
Figure. 30 FFT plot for output voltage of UCOPWM strategy for THI reference
Figure. 31 Output voltage generated by UPSPWM strategy for THI reference
Figure. 32 FFT plot for output voltage of UPSPWM strategy for THI reference
12. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
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Figure. 33 Output voltage generated by UVFPWM strategy for THI reference
Figure. 34 FFT plot for output voltage of UVFPWM strategy for THI reference
Figure. 35 Output voltage generated by USHPWM strategy for 60 degree reference
Figure. 36 FFT plot for output voltage of USHPWM strategy for 60 degree reference
13. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
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Figure. 37 Output voltage generated by UCOPWM strategy for 60 degree reference
Figure. 38 FFT plot for output voltage of UCOPWM strategy for 60 degree reference
Figure. 39 Output voltage generated by UPSPWM strategy for 60 degree reference
Figure. 40 FFT plot for output voltage of UPSPWM strategy for 60 degree reference
14. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
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Figure. 41 Output voltage generated by UVFPWM strategy for 60 degree reference
Figure. 42 FFT plot for output voltage of UVFPWM strategy for 60 degree reference
Figure. 43 Output voltage generated by USHPWM strategy for stepped reference
Figure. 44 FFT plot for output voltage of USHPWM strategy for stepped reference
15. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
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Figure. 45 Output voltage generated by UCOPWM strategy for stepped reference
Figure. 46 FFT plot for output voltage of UCOPWM strategy for stepped reference
Figure. 47 Output voltage generated by UPSPWM strategy for stepped reference
Figure. 48 FFT plot for output voltage of UPSPWM strategy for stepped reference
16. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
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Figure. 49 Output voltage generated by UVFPWM strategy for stepped reference
Figure. 50 FFT plot for output voltage of UVFPWM strategy for stepped reference
Table 1. % THD for different modulation indices for sinusoidal reference
ma USHPWM UCOPWM UPSPWM UVFPWM
1 28.08 39.08 34.34 28.19
0.9 35.35 46.58 44.24 35.33
0.8 40.46 56.48 52.60 40.48
0.7 44.28 71.91 58.48 44.63
0.6 46.10 88.32 60.22 45.89
Table.2 VRMS (fundamental) for different modulation indices with sinusoidal reference
ma USHPWM UCOPWM UPSPWM UVFPWM
1 305.3 315.9 291.2 305.4
0.9 272.4 290 252.4 272.3
0.8 240 258.4 212.9 239.8
0.7 206.2 218.4 176.1 206
0.6 173.8 181.6 141.6 246.8
Table.3 % THD for different modulation indices for THI PWM reference
17. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
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ma USHPWM UCOPWM UPSPWM UVFPWM
1 28.79 33.36 31.14 28.89
0.9 36.60 39.05 42.56 36.74
0.8 43.15 47.80 52.61 43.42
0.7 46.69 64.71 59.23 46.90
0.6 44.93 81.49 60.36 45.02
Table.4 VRMS (fundamental) for different modulation indices with THI PWM reference
ma USHPWM UCOPWM UPSPWM UVFPWM
1 357.2 364.3 349.4 357.1
0.9 319.3 337.9 305.4 319.4
0.8 281.3 306.3 259.5 281.4
0.7 242.4 260.6 215.1 242.6
0.6 203.5 217.1 168.2 203.6
Table.5 % THD for different modulation indices with 60 degree PWM reference
ma USHPWM UCOPWM UPSPWM UVFPWM
1 24.72 30.99 24.94 37.31
0.9 34.13 37.41 38.88 34.22
0.8 41.38 42.30 49.60 41.55
0.7 46.24 61.03 58.34 46.44
0.6 46.10 78.05 61.86 46.04
Table.6 VRMS (fundamental) for different modulation indices with 60 degree PWM reference
ma USHPWM UCOPWM UPSPWM UVFPWM
1 372.6 374.8 369.6 373.1
0.9 332.4 345.9 321.8 332.5
0.8 292.9 319.7 274.6 293.1
0.7 253.3 271.5 227.4 253.1
0.6 212.5 226.3 180.1 212.5
Table.7 % THD for different modulation indices with Stepped wave reference
ma USHPWM UCOPWM UPSPWM UVFPWM
1 26.22 38.38 31.09 26.01
0.9 34.84 46.35 42.77 34.69
0.8 40.58 55.94 51.94 41.22
0.7 43.66 72.29 58.16 44.92
0.6 48.84 88.16 61.42 48.32
18. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
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Table.8 VRMS (fundamental) for different modulation indices with Stepped wave reference
ma USHPWM UCOPWM UPSPWM UVFPWM
1 305.4 318.9 295.5 304.9
0.9 273.7 286 256.1 272.9
0.8 244.5 257.7 219.2 242.6
0.7 215 218.3 182.3 212.4
0.6 180.6 182.3 145.2 179.6
Table.9 Crest Factor for different modulation indices with sinusoidal reference
ma USHPWM UCOPWM UPSPWM UVFPWM
1 1.4140 1.4140 1.4144 1.4142
0.9 1.4141 1.4144 1.4144 1.4142
0.8 1.4142 1.4144 1.4142 1.4140
0.7 1.4146 1.4139 1.4145 1.4140
0.6 1.4143 1.4140 1.4145 1.4143
Table.10 Crest Factor for different modulation indices with THI PWM reference
ma USHPWM UCOPWM UPSPWM UVFPWM
1 1.4140 1.4139 1.4141 1.4141
0.9 1.4140 1.4143 1.4142 1.4139
0.8 1.4141 1.4142 1.4142 1.4140
0.7 1.4141 1.4144 1.4142 1.4142
0.6 1.4147 1.4140 1.4137 1.4145
Table.11 Crest Factor for different modulation indices with 60 degree PWM reference
ma USHPWM UCOPWM UPSPWM UVFPWM
1 1.4143 1.4143 1.4142 1.4143
0.9 1.4139 1.4142 1.4142 1.4141
0.8 1.4141 1.4141 1.4140 1.4141
0.7 1.4141 1.4143 1.4142 1.4144
0.6 1.4141 1.4140 1.4142 1.4145
Table.12 Crest Factor for different modulation indices with Stepped wave reference
ma USHPWM UCOPWM UPSPWM UVFPWM
1 1.4142 1.4142 1.4142 1.4142
0.9 1.4143 1.4188 1.4139 1.4144
0.8 1.4143 1.4140 1.4142 1.4142
0.7 1.4139 1.4141 1.4141 1.4138
0.6 1.4141 1.4147 1.4146 1.4136
19. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
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Table.13 Form Factor for different modulation indices with sinusoidal reference
ma USHPWM UCOPWM UPSPWM UVFPWM
1 15265 15795 14560 15270
0.9 13620 14500 12620 13615
0.8 12000 12920 10645 11990
0.7 20620 10920 8805 10300
0.6 17380 9080 7080 17450
Table.14 Form Factor for different modulation indices with THI PWM reference
ma USHPWM UCOPWM UPSPWM UVFPWM
1 17860 18215 17470 17855
0.9 15965 16895 15270 15970
0.8 14065 15315 12975 14070
0.7 12120 13030 10755 12130
0.6 10175 10855 8410 10180
Table.15 Form Factor for different modulation indices with 60 degree PWM reference
ma USHPWM UCOPWM UPSPWM UVFPWM
1 18630 18740 18480 18655
0.9 16620 17295 16090 16625
0.8 14645 15985 13730 14655
0.7 12665 13575 11370 12655
0.6 10625 11315 9005 10625
Table.16 Form Factor for different modulation indices with Stepped wave reference
ma USHPWM UCOPWM UPSPWM UVFPWM
1 15270 15945 14775 15245
0.9 13685 14300 12805 13645
0.8 12225 12885 10960 12130
0.7 10750 10915 9115 10620
0.6 18060 9115 7260 17960
Table.17 Distortion Factor for different modulation indices with Sinusoidal reference
ma USHPWM UCOPWM UPSPWM UVFPWM
1 0.1906 0.2210 0.9087 0.174
0.9 0.1615 0.4138 0.9493 0.182
0.8 0.1627 0.692 0.8822 0.189
0.7 0.201 0.834 0.897 0.221
0.6 0.079 0.911 0.328 0.028
20. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
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Table.18 Distortion Factor for different modulation indices with THI PWM reference
ma USHPWM UCOPWM UPSPWM UVFPWM
1 2.226 2.308 1.944 2.2180
0.9 2.192 2.199 2.007 2.2
0.8 2.269 2.072 2.007 2.280
0.7 2.22 2.09 1.947 2.243
0.6 2.217 2.015 2.079 2.227
Table.19 Distortion Factor for different modulation indices with 60 degree PWM reference
ma USHPWM UCOPWM UPSPWM UVFPWM
1 2.148 2.282 1.940 2.185
0.9 2.131 2.221 1.914 2.141
0.8 2.176 2.061 1.929 2.195
0.7 2.228 2.044 1.97 2.206
0.6 2.156 1.969 2.012 2.155
Table.20 Distortion Factor for different modulation indices with Stepped wave reference
ma USHPWM UCOPWM UPSPWM UVFPWM
1 0.429 0.184 0.191 0.472
0.9 0.395 0.419 1.206 0.459
0.8 0.293 0.818 1.138 0.442
0.7 0.187 0.97 0.972 0.4
0.6 0.089 1.034 0.685 0.268
8. CONCLUSIONS
From the Tables-1, 3, 5 and 7 is shown that USHPWM method produce lesser total harmonic
distortion compared to other strategies developed. UCOPWM with Sine, THI, 60 degree and
Stepped wave reference found to perform better since it provides more VRMS (Tables - 2, 4, 6 and
8). (Tables - 9, 10, 11 and 12) provide crest factor, (Tables - 13, 14, 15 and 16) provide FF for all
modulating indices and (Tables 17,18,19 and 20) provide DF.
21. International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
31
REFERENCES
[1] Babaei, E. ; Laali, S. ; Bayat, Z. (2015). “A Single-Phase Cascaded Multilevel Inverter Based on a
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[2] Selvamuthukumaran, R. ; Garg, A. ; Gupta, R. (2015). “Hybrid Multicarrier Modulation to Reduce
Leakage Current in a Transformerless Cascaded Multilevel Inverter for Photovoltaic Systems,” IEEE
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[4] Kai-Ming Tsang ; Wai-Lok Chan, (2014). “Single DC source three-phase multilevel inverter using
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[7] Chung-Ming Young ; Neng-Yi Chu ; Liang-Rui Chen ; Yu-Chih Hsiao ; Chia-Zer Li., (2013) “A
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![International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
DOI : 10.14810/ijscmc.2015.4202 11
PERFORMANCE EVALUATION ON UNIPOLAR PWM
STRATEGIES FOR THREE PHASE DIODE CLAMPED
MULTILEVEL INVERTER
C.R.Balamurugan1
S.P.Natarajan2
R.Bensraj3
and T.S.Anandhi4
1
Department of EEE, Arunai Engineering College, Tiruvannamalai
2,3,4
Annamalai University, Chidambaram, Tamilnadu
ABSTRACT
This paper proposes different types of modulation methods for the Diode Clamped Multi Level Inverter
(DCMLI). In this paper, a DCMLI is controlled with Sinusoidal PWM technique (SPWM), Third Harmonic
Injection PWM technique, Sixty degree PWM technique and Stepped wave technique with Sub harmonic
(SHPWM), Carrier Overlapping (CO), Phase shift (PS) , Variable frequency (VF) and the variation of
Total Harmonic Distortion (THD) in their outputs are observed and also chosen inverter is controlled by
SPWM technique, THI PWM technique, Sixty degree PWM and Stepped wave technique by varying the
modulation index. Simulation are performed using MATLAB-SIMULINK. It is observed that SHPWM
strategy provide output with relatively low distortion. It is observed that COPWM strategy provides higher
Vrms compared to other modulation strategies.
KEYWORDS
THD, Stepped, THIPWM, 60 degree PWM, unipolar.
1.INTRODUCTION
MLIs easily produce high-power, high-voltage output with the multilevel structure because of the
way the device voltage stresses are controlled in the structure. Babaei et al [1] proposed
a inverter contained of a series connection of the proposed basic unit and is able to only generate
positive levels at the output. Selvamuthukumaran et al[2] also proposed a H-MCPWM strategy
ensures low leakage current in the transformer less PV inverter system with simplicity in
implementation of the modulation strategy using lesser number of carriers. Edpuganti et al [3]
suggested to operate a multilevel inverter for motor drive using SOP strategy. Kai-Ming Tsang et
al [4] proposed a topology approach enables multilevel output to be realized by a few cascaded
H-bridges and a three-leg inverter using lower number of power switches. Babaei et al [5]
suggested a topology which requires lesser number of power switches and dc voltage sources.
Odeh et al [6] developed a multicarrier, phase disposition PWM technique is applied to generate
the gating signals for the power switches. Young et al. [7] discusses a combination of batteries
can be controlled according to the batteries' voltages to implement the battery-balancing function.
Gupta et al [8] made a synthesis of multilevel waveform using minimum number of power
switches as compared to the classical topologies. Cougo et al [9] suggest pulse width modulation
technique based on carriers' disposition and on zero sequence injection is analyzed for parallel
multilevel inverters. Zixin et al. [10] discuses level of the output voltage is only half of the dc-link
voltage in all conditions, leading to much reduced dv/dt. Palanivel et al [11] observed this
topologies of multilevel inverter have several advantages such as high output voltage, lower](https://image.slidesharecdn.com/4215ijscmc02-220714084349-5774ee90/85/PERFORMANCE-EVALUATION-ON-UNIPOLAR-PWM-STRATEGIES-FOR-THREE-PHASE-DIODE-CLAMPED-MULTILEVEL-INVERTER-1-320.jpg)
![International Journal of Soft Computing, Mathematics and Control (IJSCMC),Vol. 4, No. 2, May 2015
12
electromagnetic interference, lower THD. Khoucha et al [12] developed a symmetrical and
asymmetrical arrangements of five- and seven-level H-bridge inverters are compared in order to
determine optimum arrangement with lower switching losses and optimized output voltage
quality. Jing zhao et al [13] suggested minimum number of devices switching on or off within
broad modulation index range, accordingly reducing switching losses and reduce the amplitude of
lower harmonics. Naumanem et al [14] proposed pulsed inverter voltage and the impedance
mismatch between the cable and the motor cause an oscillating overvoltage in the motor
terminals.
2. MULTILEVEL INVERTER
The MLIs synthesize a near sinusoidal voltage from several DC voltage sources. A diode clamped
multilevel (m-level) inverter typically consists of (m-1) capacitors on the bus and produces m
levels on the phase voltage. Fig.1 shows three phase five level diode clamped multilevel inverter.
The numbering order of the switches for R-phase is Sa1, Sa2, Sa3, Sa4, Sa1’, Sa2’,Sa3’ and Sa4’.
Figure. 1 Power Circuit for 3Φ DCMLI
The gate signals for chosen five level diode clamped inverter are simulated using MATLAB-
SIMULINK. The control gate signals are developed and checked. Fig. 2 shows a sample
SIMULINK model.
Figure. 2 Sample control signal generation SIMULINK](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)