Abstract
A Three phase bidirectional AC to AC buck converter circuit using power MOSFET operating in high frequency chopping mode is simulated and analyzed for electrical parameters such as output phase voltage, input line current, input power factor, harmonic profile and efficiency using MATLAB/simulink software package. The various PWM techniques such as symmetrical ramp-DC PWM (SRDPWM), asymmetrical ramp-triangular PWM (ARTPWM), asymmetrical sinusoidal PWM type-1 [ASPWM1] and asymmetrical sinusoidal PWM type-2 [ASPWM2] techniques are adopted to analyze the harmonic profile, input power factor and efficiency of the converter. The rms value of the output phase voltage, output line current and source current can be significantly increased by varying the duty ratio K in case of symmetrical PWM control strategy and modulation index MI in case of asymmetrical PWM control strategies independent of variation in switching frequency. It is observed from the simulation results that the ASPWM1 switching strategy gives more output phase voltage, input power factor, efficiency by increasing modulation index MI and reduced low order harmonics of output voltage and source current by increasing the number of pulses per half cycle P compared to other PWM techniques rendering easy and economical filteration.
Keywords: Three phase AC chopper, symmetrical ramp-DC PWM, asymmetrical ramp-triangular PWM, asymmetrical sinusoidal PWM technique, harmonic profile, power factor, efficiency
The study made in this paper concerns the use of the voltage-oriented control (VOC) of three-phase pulse width modulation (PWM) rectifier with constant switching frequency. This control method, called voltage-oriented controlwith space vector modulation (VOC-SVM). The proposed control scheme has been founded on the transformation between stationary (α-β) and and synchronously rotating (d-q) coordinate system, it is based on two cascaded control loops so that a fast inner loop controls the grid current and an external loop DC-link voltage, while the DC-bus voltage is maintained at the desired level and ansured the unity power factor operation. So, the stable state performance and robustness against the load’s disturbance of PWM rectifiers are boths improved. The proposed scheme has been implemented and simulated in MATLAB/Simulink environment. The control system of the VOC-SVM strategy has been built based on dSPACE system with DS1104 controller board. The results obtained show the validity of the model and its control method. Compared with the conventional SPWM method, the VOC-SVM ensures high performance and fast transient response.
Optimal Location of Statcom for Power Flow ControlIJMER
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.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
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.
Power flow control in parallel transmission lines based on UPFCjournalBEEI
The power flow controlled in the electric power network is one of the main factors that affected the modern power systems development. The unified power flow controller (UPFC) is a FACTS powerful device that can control both active and reactive power flow of parallel transmission lines branches. In this paper, modelling and simulation of active and reactive power flow control in parallel transmission lines using UPFC with adaptive neuro-fuzzy logic is proposed. The mathematical model of UPFC in power flow is also proposed. The results show the ability of UPFC to control the flow of powers components "active and reactive power" in the controlled line and thus the overall power regulated between lines.
Small Signal Modeling Of Controller For Statcom Used In Distribution System F...IJERA Editor
In this paper non-linear model of the STATCOM is linearized and the following strategies have been adopted .
Hence, a small signal model is adopted here. Here, the grid voltage lags the fundamental component of the
STATCOM converter terminal voltage with a phase angle difference
' '
. Small signal modeling of the phase
angle
' '
and modulation index
' m '
is also done. A single PI-controller for the reactive component current of
the STATCOM has been designed. In this model, the DC-link capacitor voltage is held constant without using a
separate controller. The STATCOM are designed using SVPWM technique. Through adjustment of the
modulation index, fast modulation of the STATCOM reactive power output can be achieved due to high
sensitivity of the same with respect to the output voltage of the STATCOM VSC. The model, with PI controllers
has been simulated in MATLAB/SIMULINK environment with variation of the pre-charge voltage on the DClink
capacitor with linear loads (inductive). Improvement of the power factor of the grid current is achieved for
linear loads.
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.
A Novel Control Strategy of Indirect Matrix Converter Using Space Vector Modu...IJPEDS-IAES
This paper introduces a control scheme of Indirect Matrix Converter which includes space vector modulation to stabilize the frequency variations. The terminal voltage and frequency of any synchronous machine can be controlled easily with this scheme. Further the control strategy is proposed and implemented in Matlab/Simulink Embedded system which gives significant better performance compared to conventional control technique like better Total Harmonic Distortion (THD), more output voltage with same Modulation Index, less switching stress and less switching loss. This method might prove effective for wind energy conversion system using DFIG as the DFIG speed is close to synchronous speed. The complete control strategy is verified using MATLAB/Simulink.
The study made in this paper concerns the use of the voltage-oriented control (VOC) of three-phase pulse width modulation (PWM) rectifier with constant switching frequency. This control method, called voltage-oriented controlwith space vector modulation (VOC-SVM). The proposed control scheme has been founded on the transformation between stationary (α-β) and and synchronously rotating (d-q) coordinate system, it is based on two cascaded control loops so that a fast inner loop controls the grid current and an external loop DC-link voltage, while the DC-bus voltage is maintained at the desired level and ansured the unity power factor operation. So, the stable state performance and robustness against the load’s disturbance of PWM rectifiers are boths improved. The proposed scheme has been implemented and simulated in MATLAB/Simulink environment. The control system of the VOC-SVM strategy has been built based on dSPACE system with DS1104 controller board. The results obtained show the validity of the model and its control method. Compared with the conventional SPWM method, the VOC-SVM ensures high performance and fast transient response.
Optimal Location of Statcom for Power Flow ControlIJMER
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.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
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.
Power flow control in parallel transmission lines based on UPFCjournalBEEI
The power flow controlled in the electric power network is one of the main factors that affected the modern power systems development. The unified power flow controller (UPFC) is a FACTS powerful device that can control both active and reactive power flow of parallel transmission lines branches. In this paper, modelling and simulation of active and reactive power flow control in parallel transmission lines using UPFC with adaptive neuro-fuzzy logic is proposed. The mathematical model of UPFC in power flow is also proposed. The results show the ability of UPFC to control the flow of powers components "active and reactive power" in the controlled line and thus the overall power regulated between lines.
Small Signal Modeling Of Controller For Statcom Used In Distribution System F...IJERA Editor
In this paper non-linear model of the STATCOM is linearized and the following strategies have been adopted .
Hence, a small signal model is adopted here. Here, the grid voltage lags the fundamental component of the
STATCOM converter terminal voltage with a phase angle difference
' '
. Small signal modeling of the phase
angle
' '
and modulation index
' m '
is also done. A single PI-controller for the reactive component current of
the STATCOM has been designed. In this model, the DC-link capacitor voltage is held constant without using a
separate controller. The STATCOM are designed using SVPWM technique. Through adjustment of the
modulation index, fast modulation of the STATCOM reactive power output can be achieved due to high
sensitivity of the same with respect to the output voltage of the STATCOM VSC. The model, with PI controllers
has been simulated in MATLAB/SIMULINK environment with variation of the pre-charge voltage on the DClink
capacitor with linear loads (inductive). Improvement of the power factor of the grid current is achieved for
linear loads.
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.
A Novel Control Strategy of Indirect Matrix Converter Using Space Vector Modu...IJPEDS-IAES
This paper introduces a control scheme of Indirect Matrix Converter which includes space vector modulation to stabilize the frequency variations. The terminal voltage and frequency of any synchronous machine can be controlled easily with this scheme. Further the control strategy is proposed and implemented in Matlab/Simulink Embedded system which gives significant better performance compared to conventional control technique like better Total Harmonic Distortion (THD), more output voltage with same Modulation Index, less switching stress and less switching loss. This method might prove effective for wind energy conversion system using DFIG as the DFIG speed is close to synchronous speed. The complete control strategy is verified using MATLAB/Simulink.
Three Phase Twelve Pulse Controlled Rectifier with Reduced Output Current Har...paperpublications3
Abstract: The power conversion from AC to DC and vice versa is basic need for several industrial applications, single phase or three phase controlled or uncontrolled convertor is used for this purpose. In these types of convertors large lower order harmonics are present. A twelve pulse three phase rectifier is used for reducing harmonics in high power applications, but the (12m±1) order harmonics are still present in the system. For further reduction of harmonics this paper proposes a PI controller based synchronous twelve pulse generator used for gate triggering of controlled twelve pulse rectifier with DC motor as a load.
This paper introduces the modelling of a novel three phase AC-AC converter with indirect use of a capacitor as DC voltage link. The proposed converter has high efficiency because it uses Space Vector PWM (SVPWM) technique at both rectificier and inverter stages to operate the pulse width modulation in IGBT switches. The novel converter is equipped with a power factor control to shape the rectifier input current waveform to be sinusoidal and to be in phase with the input voltage. To keep the DC voltage stable, the converter utilizes PI controllers. Simulations are conducted for output voltage from 120 to 300 Volts with output frequency ranging from 30 Hz to 60 Hz. The simulation results show that the converter is able to maintain stable the DC voltage and current. Furthermore, the model demonstrates the benefits of proposed converter in terms of acquiring high input power factor and sinusoidal current waveform at the output side of the inverter.
Analysis of dc capacitor voltage balance method for h bridge inverter based p...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
A Three Phase AC-AC ZCS Resonant Converter for Induction HeatingIJMTST Journal
Generally, domestic induction-heating technology requires a high output power levels with less number of
components in a compact size. To satisfy these requirements, the basic circuit configurations are considered
based on the combination of a rectifier and a inverter. The main disadvantage of this method has low-efficient
and economic problems. This paper proposes a new concept unlike previous method, i.e the direct conversion
of ac–ac converter for reducing the component count, reduce cost, improve reliability, and also efficiency.
Generally, the proposed converter is a voltage-source based series-resonant converter used for controlling
output power, and minimizing the control complexity. This paper also proposes a concept of AC-AC converter
based three phase Induction Heating applications.
Torque Ripple Minimization of a BLDC Motor Drive by Using Electronic Commutat...AI Publications
Brushless DC motors are having a major problem with harmonics in torque. The variations in speed and production of noise should be minimized by using proper topologies. BLDC motors have been gaining attention from different Industrial and domestic appliance manufacturers, because of their high efficiency, high power density and easy maintenance and low cost. This paper presents a three phase BLDC motor with low cost drive to be driven without DC link capacitor. The proposed technique uses an electronic commutation and operates the machine exclusive of the intermediate DC link capacitor. The designing of Brushless DC motor drive system along with control system for torque ripple minimization, speed controller and current controllers are presented using MATLAB / SIMULINK and results are evaluated.
Engineering Research Publication
Best International Journals, High Impact Journals,
International Journal of Engineering & Technical Research
ISSN : 2321-0869 (O) 2454-4698 (P)
www.erpublication.org
Enhancement of Power System Dynamics Using a Novel Series Compensation SchemeIJMER
Phase imbalanced capacitive compensation is a “hybrid” series compensation scheme, where the
series capacitive compensation in one phase is created using a single-phase TCSC in series with a fixed capacitor
(Cc), and the other two phases are compensated by fixed series capacitors (C). The TCSC control is initially set
such that its equivalent compensations at the power frequency combined with the fixed capacitor yield a
resultant compensation equal to the other two phases. Thus, the phase balance is maintained at the power
frequency while at any other frequency, a phase imbalance is created. The effectiveness of the scheme in damping
power system oscillations for various network conditions, namely different system faults and tie-line power flows is
evaluated using the MATLAB/SIMULINK Software
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.
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.
Development of a Novel Three Phase Grid-Tied Multilevel Inverter TopologyIAES-IJPEDS
The conventional line-commutated ac-to-dc converters/ inverters have square-shaped line current. It contains higher-order harmonics which generates EMI and it causes more heating of the core of distribution or power transformers. PWM based inverters using MOSFET/IGBT have higher switching losses, and the power handling capability and reliability are quite low in comparison to thyristors/ SCR. A thyristor based forced commutated inverters are not suitable for PWM applications due to the problems of commutation circuits. A pure sinusoidal voltage output or waveform with low harmonic contents is most desirable for ac load using dc to ac conversion. This paper presents a new multilevel inverter topology in which three phase ac- to-dc converter circuits are used in inversion mode by controlling the switching angle. Due to natural commutation, no separate circuit is required for synchronization. In this paper simulation and analysis are done for grid-tied three-phase 6-pulse, Two three-phase, 3-pulse and 12-pulse converter. These converters are analysed for different battery voltage and different switching angle combinations in order to reduce the total harmonic distortion (THD). Three-phase harmonic filters are further added to the grid side to reduce the harmonic content in the line current. A comparative study of these converters is also presented in this paper.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
H6 Transformer less Topology and Its Modulation Strategy for Mitigating Cm Cu...IJERA Editor
MATLABbasedsingle-phase three-level topology for a transformer less photovoltaic system is presented in this paper. Compared with the conventional H-bridge topology, it only needs two additional asymmetrically distributed switches, and the system common-mode voltage can be kept constant with a simple modulation scheme. Family of H6 transformer less inverter topologies with low leakage currents is proposed and highly efficient and reliable inverter concept (HERIC) topology is also presented in this paper. The proposed inverter can also operate with high frequency by retaining high efficiency which enables reduced cooling system. Finally, the proposed new topology is simulated by MATLAB/Simulink software to validate the accuracy of the theoretical explanation.
Three Phase Twelve Pulse Controlled Rectifier with Reduced Output Current Har...paperpublications3
Abstract: The power conversion from AC to DC and vice versa is basic need for several industrial applications, single phase or three phase controlled or uncontrolled convertor is used for this purpose. In these types of convertors large lower order harmonics are present. A twelve pulse three phase rectifier is used for reducing harmonics in high power applications, but the (12m±1) order harmonics are still present in the system. For further reduction of harmonics this paper proposes a PI controller based synchronous twelve pulse generator used for gate triggering of controlled twelve pulse rectifier with DC motor as a load.
This paper introduces the modelling of a novel three phase AC-AC converter with indirect use of a capacitor as DC voltage link. The proposed converter has high efficiency because it uses Space Vector PWM (SVPWM) technique at both rectificier and inverter stages to operate the pulse width modulation in IGBT switches. The novel converter is equipped with a power factor control to shape the rectifier input current waveform to be sinusoidal and to be in phase with the input voltage. To keep the DC voltage stable, the converter utilizes PI controllers. Simulations are conducted for output voltage from 120 to 300 Volts with output frequency ranging from 30 Hz to 60 Hz. The simulation results show that the converter is able to maintain stable the DC voltage and current. Furthermore, the model demonstrates the benefits of proposed converter in terms of acquiring high input power factor and sinusoidal current waveform at the output side of the inverter.
Analysis of dc capacitor voltage balance method for h bridge inverter based p...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
A Three Phase AC-AC ZCS Resonant Converter for Induction HeatingIJMTST Journal
Generally, domestic induction-heating technology requires a high output power levels with less number of
components in a compact size. To satisfy these requirements, the basic circuit configurations are considered
based on the combination of a rectifier and a inverter. The main disadvantage of this method has low-efficient
and economic problems. This paper proposes a new concept unlike previous method, i.e the direct conversion
of ac–ac converter for reducing the component count, reduce cost, improve reliability, and also efficiency.
Generally, the proposed converter is a voltage-source based series-resonant converter used for controlling
output power, and minimizing the control complexity. This paper also proposes a concept of AC-AC converter
based three phase Induction Heating applications.
Torque Ripple Minimization of a BLDC Motor Drive by Using Electronic Commutat...AI Publications
Brushless DC motors are having a major problem with harmonics in torque. The variations in speed and production of noise should be minimized by using proper topologies. BLDC motors have been gaining attention from different Industrial and domestic appliance manufacturers, because of their high efficiency, high power density and easy maintenance and low cost. This paper presents a three phase BLDC motor with low cost drive to be driven without DC link capacitor. The proposed technique uses an electronic commutation and operates the machine exclusive of the intermediate DC link capacitor. The designing of Brushless DC motor drive system along with control system for torque ripple minimization, speed controller and current controllers are presented using MATLAB / SIMULINK and results are evaluated.
Engineering Research Publication
Best International Journals, High Impact Journals,
International Journal of Engineering & Technical Research
ISSN : 2321-0869 (O) 2454-4698 (P)
www.erpublication.org
Enhancement of Power System Dynamics Using a Novel Series Compensation SchemeIJMER
Phase imbalanced capacitive compensation is a “hybrid” series compensation scheme, where the
series capacitive compensation in one phase is created using a single-phase TCSC in series with a fixed capacitor
(Cc), and the other two phases are compensated by fixed series capacitors (C). The TCSC control is initially set
such that its equivalent compensations at the power frequency combined with the fixed capacitor yield a
resultant compensation equal to the other two phases. Thus, the phase balance is maintained at the power
frequency while at any other frequency, a phase imbalance is created. The effectiveness of the scheme in damping
power system oscillations for various network conditions, namely different system faults and tie-line power flows is
evaluated using the MATLAB/SIMULINK Software
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.
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.
Development of a Novel Three Phase Grid-Tied Multilevel Inverter TopologyIAES-IJPEDS
The conventional line-commutated ac-to-dc converters/ inverters have square-shaped line current. It contains higher-order harmonics which generates EMI and it causes more heating of the core of distribution or power transformers. PWM based inverters using MOSFET/IGBT have higher switching losses, and the power handling capability and reliability are quite low in comparison to thyristors/ SCR. A thyristor based forced commutated inverters are not suitable for PWM applications due to the problems of commutation circuits. A pure sinusoidal voltage output or waveform with low harmonic contents is most desirable for ac load using dc to ac conversion. This paper presents a new multilevel inverter topology in which three phase ac- to-dc converter circuits are used in inversion mode by controlling the switching angle. Due to natural commutation, no separate circuit is required for synchronization. In this paper simulation and analysis are done for grid-tied three-phase 6-pulse, Two three-phase, 3-pulse and 12-pulse converter. These converters are analysed for different battery voltage and different switching angle combinations in order to reduce the total harmonic distortion (THD). Three-phase harmonic filters are further added to the grid side to reduce the harmonic content in the line current. A comparative study of these converters is also presented in this paper.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
H6 Transformer less Topology and Its Modulation Strategy for Mitigating Cm Cu...IJERA Editor
MATLABbasedsingle-phase three-level topology for a transformer less photovoltaic system is presented in this paper. Compared with the conventional H-bridge topology, it only needs two additional asymmetrically distributed switches, and the system common-mode voltage can be kept constant with a simple modulation scheme. Family of H6 transformer less inverter topologies with low leakage currents is proposed and highly efficient and reliable inverter concept (HERIC) topology is also presented in this paper. The proposed inverter can also operate with high frequency by retaining high efficiency which enables reduced cooling system. Finally, the proposed new topology is simulated by MATLAB/Simulink software to validate the accuracy of the theoretical explanation.
Performance Web côté client - Daspet / Sullivan - Paris Web 2008Association Paris-Web
80% des problèmes de performance Web se situe au niveau des échanges avec le navigateur et sur le navigateur lui-même : échanges réseau, rendu dans le navigateur, organisation des composants dans une page etc.
Nous aborderons les principales problématiques et les solutions à mettre en œuvre. Forts de l'expérience de l'équipe performance de Yahoo!, à la fin de cette session vous saurez aborder la question des performances Web du point de vue du visiteur et mettre en œuvre les actions correctrices sur vos sites Web.
Etude sur l'hygiène nasale des FrançaisIpsos France
Etude Ipsos pour le Groupe Batteur
Si les troubles nasaux concernent et gênent la quasi-totalité des Français, l’hygiène nasale est encore loin d’être généralisée, en dehors du traitement des jeunes enfants.
Pourtant, les bénéfices d’une telle pratique pour la santé et le confort sont unanimement reconnus par les utilisateurs de solutions pharmaceutiques, aussi bien en termes de traitement que de prévention.
A tutorial history of the development of liquid fuel nuclear reactors -- aqueous, metal, and molten salt, which has the potential to provide safe, carbon free, affordable energy that can address global warming and foster prosperous lifestyles in the developing nations that include population stabilizqtion.
Advantages of Soft Start Motor ControlDesign World
Soft starters for AC motors offer many benefits, with the most significant being a reduction of mechanical stresses on the motor and shaft as well as other components in a system, thereby extending equipment life. They also contribute to smarter use of power and less inrush current, which can minimize penalties from utility companies. An industry expert from Eaton explains these and other benefits of soft starters as well as some of the advantages of soft starters over traditional motor starters.
Viewers will also learn about:
• How to monitor and protect your equipment and reduce overall system costs
• How to select soft starters for unique applications
• Reducing or eliminating water hammer effect and check valve slamming
• Considerations for heavy-duty applications
Further, specific attention will be given how to select soft start controllers for unique application requirements.
Synodiance > 10 régles pour un site web bien référencé - Webikeo - 09/02/2016Search Foresight
Loin de se limiter à des recettes toutes faites, le métier de SEO se complexifie constamment. Retour en ce début 2016 sur les pratiques SEO à privilégier en 2016 : l’organisation d’un site en silo, l’importance de la sémantique, le poids du linking, l’UX mobile, …
Report On diode clamp three level inverterVinay Singh
three level diode clamp inverter. that converts any type of DC ( rectified, PV cell, battery etc.) to AC supply. we made by mosfet and ardiuno . in this ppt we present the Simulink model of a three-level inverter and the hardware reort of the inverter.
also discuss about other level inverter and there THD analysis, simulink model and detail. compression between another inverter.
A novel three phase bidirectional AC buck converter circuit using power
MOSFET is analyzed for input power factor, harmonic profile and efficiency of the
converter for power quality improvement. The equal PWM (EPWM) technique is a used to
increase number of pulses per half cycle (P) in order to vary these parameters. The rms
value of the fundamental component of the output voltage can be increased by varying the
duty ratio (K) of the pulses. It is observed from the simulation results obtained using
MATLAB/simulink that the proposed scheme using EPWM technique significantly reduces
low order harmonics, eliminates certain harmonics for certain values of P, improves input
power factor and hence significantly reduces the filter size of the converter.
Computer Science
Active and Programmable Networks
Active safety systems
Ad Hoc & Sensor Network
Ad hoc networks for pervasive communications
Adaptive, autonomic and context-aware computing
Advance Computing technology and their application
Advanced Computing Architectures and New Programming Models
Advanced control and measurement
Aeronautical Engineering,
Agent-based middleware
Alert applications
Automotive, marine and aero-space control and all other control applications
Autonomic and self-managing middleware
Autonomous vehicle
Biochemistry
Bioinformatics
BioTechnology(Chemistry, Mathematics, Statistics, Geology)
Broadband and intelligent networks
Broadband wireless technologies
CAD/CAM/CAT/CIM
Call admission and flow/congestion control
Capacity planning and dimensioning
Changing Access to Patient Information
Channel capacity modelling and analysis
Civil Engineering,
Cloud Computing and Applications
Collaborative applications
Communication application
Communication architectures for pervasive computing
Communication systems
Computational intelligence
Computer and microprocessor-based control
Computer Architecture and Embedded Systems
Computer Business
Computer Sciences and Applications
Computer Vision
Computer-based information systems in health care
Computing Ethics
Computing Practices & Applications
Congestion and/or Flow Control
Content Distribution
Context-awareness and middleware
Creativity in Internet management and retailing
Cross-layer design and Physical layer based issue
Cryptography
Data Base Management
Data fusion
Data Mining
Data retrieval
Data Storage Management
Decision analysis methods
Decision making
Digital Economy and Digital Divide
Digital signal processing theory
Distributed Sensor Networks
Drives automation
Drug Design,
Drug Development
DSP implementation
E-Business
E-Commerce
E-Government
Electronic transceiver device for Retail Marketing Industries
Electronics Engineering,
Embeded Computer System
Emerging advances in business and its applications
Emerging signal processing areas
Enabling technologies for pervasive systems
Energy-efficient and green pervasive computing
Environmental Engineering,
Estimation and identification techniques
Evaluation techniques for middleware solutions
Event-based, publish/subscribe, and message-oriented middleware
Evolutionary computing and intelligent systems
Expert approaches
Facilities planning and management
Flexible manufacturing systems
Formal methods and tools for designing
Fuzzy algorithms
Fuzzy logics
GPS and location-based app
Simulation of 3-phase matrix converter using space vector modulationIJECEIAES
This paper illustrates the simulation of 3-phase matrix converter using Space Vector Modulation (SVM). Variable AC output voltage engendered using matrix converter with bidirectional power switches controlled by appropriate switching pulse. The conventional PWM converter engenders switching common mode voltage across the load system terminals, which cause to common mode current and its leads to bearing failure in load drive. These problems can be rectified using SVM and which minimize the effect on the harmonic fluctuation in AC output voltage and stress on the power switch is reduced using bidirectional switch for proposed 3-phase matrix converter. The simulation results have been presented to validate the proposed system using matlab / simulink.
AC - AC power conversions were traditionally done by using thyristor power controllers, phase angle control or by
integral cycle control, but had low PF and other disadvantages. Variable voltage, variable frequency high power conversions
are nowadays use DC link and Matrix converters, with higher efficiency and better regulation. But in situations where only
voltage regulation is required and the circuit need to be simple and less complicated, directed PWM AC-AC converters are
more preferred, due to reduced size and components. This project presents the design and simulation of a new type of AC-AC
converter which can operate as traditional non-inverting buck and boost converters, and inverting buck-boost converter as
well. This converter uses six unidirectional current flowing and bidirectional voltage blocking switches, implemented by six
reverse blocking IGBTs or series MOSFET-diode pairs, two input and output filter capacitors, and one inductor. It has no
shoot-through problem of voltage source (or capacitor) even when all switches are turned-on and therefore; PWM dead times
are not needed resulting in high quality waveforms, and solves the commutation problem without using bulky and lossy RC
snubbers or dedicated soft-commutation strategies. It has smaller switching losses because; only two switches out of six are
switched at high frequency during each half cycle of input voltage, and it can use power MOSFETs as body diode never
conducts, making it immune from MOSFET failure risk..
A Novel Power Factor Correction Rectifier for Enhancing Power QualityIJPEDS-IAES
In this paper, the disturbances in power system due to low quality of power
are discussed and a current injection method to maintain the sinusoidal input
current which will reduce the total current harmonic distortion (THD) as well
as improve the power factor nearer to unity is proposed. The proposed
method makes use of a novel controlled diode rectifier which involves the
use of bidirectional switches across the front-end rectifier and the operation
of the converter is fully analyzed. The main feature of the topology is low
cost, small size, high efficiency and simplicity, and is excellent for
retrofitting front-end rectifier of existing ac drives, UPS etc. A novel strategy
implementing reference compensation current depending on the load
harmonics and a control algorithm for three-phase three-level unity PF
rectifier which draws high quality sinusoidal supply currents and maintains
good dc link- voltage regulation under wide load variation. The proposed
technique can be applied as a retrofit to a variety of existing thyristor
converters which uses three bidirectional switches operating at low frequency
and a half-bridge inverter operating at high frequency .The total power
delivered to the load is processed by the injection network, the proposed
converter offers high efficiency and not only high power factor but also the
Total Harmonic Distortion is reduced. Theoretical analysis is verified by
digital simulation and a hardware proto type module is implemented in order
to confirm the feasibility of the proposed system. This scheme in general is
suitable for the common variable medium-to high-power level DC load
applications.
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.
Simulation of 3 Phase to 3 Phase Power Conversion Using Matrix Converter with...IJERA Editor
This paper proposes a new approach of design and implementation of 3 phase to 3 phase conversion using
matrix converter. It includes the design, modeling and implementation. The entire matrix converter circuits are
developed by mathematical model so as to reduce computational time and performances of the converter are
evaluated using MATLAB/SIMULINK for RL Load. The mathematical expressions relating the input and
output of the three phase matrix converter are implemented by using simulink block set. The duty cycles of the
matrix converter bidirectional switches are calculated using modified venturini algorithm for maximum (0.866)
and minimum (0.5) voltage transfer ratio.
In the proposed approach,instead of a conventional 3- Phase inverter a component minimized single pha se inverter is utilized which reduces the cost of the inverter,th e switching losses,and the complexity of interface circuits to generate logic signals. A performance comparison of the prop osed inverter fed drive with a conventional 3Phase inverter fed drive is also mode in terms of speed response and t otal harmonic distortion (THD) of the stator curren t. The proposed inverter fed IM drive is found acceptable consideri ng its cost reduction and other advantageous featur es. A general pulse width modulation (PWM) method for c ontrol of 1-phase inverters is presented. The vecto r PWM offers a simple method to select three or four vectors tha t effectively synthesize the desired output voltage,even in presence of voltage oscillations across the two dc-link capacit ors. The influence of different switching patterns on output voltage symmetry,current waveform,switching frequency and common mode voltage can be examined. The paper als o discusses how the use of the wye and delta connecti ons of the motor windings affects the implementatio n of the pulse width modulator.
Bridgeless CUK Power Factor Corrector with Regulated Output Voltagepaperpublications3
Abstract:A single-phase, bridgeless Cuk AC/DC power factor correction (PFC) rectifier with regulated positive output voltage is proposed in this work. For low output voltage product applications, the rectifier is designed to convert high input voltage to low output voltage. This work presents bridgeless single-phase AC-DC power factor correction (PFC) rectifier based on Cuk topology. The topology does not possess input diode bridge and have only single semiconductor switches in the current owing path during each interval of the switching cycle, which resulting in less conduction losses and better thermal management. This topology is designed to work in discontinuous conduction mode (DCM). The advantages of Cuk converter are also available when bridgeless circuit topology is introduced. The operation is symmetrical in two half-line cycles of input voltage. In conventional, output voltage varies according to input voltage. A closed loop control technique is designed to regulate the output voltage in the desired level. Performance and applicability of this converter is presented on the basis of simulation in MATLAB/SIMULINK.
Performance of PWM Rectifier with Different Types of Loadijsrd.com
The paper presents the decoupled vector control of the PWM rectifier with the nonlinear DC-link voltage regulation and the load compensating feed forward. The concept of the proposed control system is based on Voltage Oriented Control with Space-Vector Pulse Width Modulation (SV-PWM). For the high-performance operation of the PWM rectifier and the satisfactory current tracing the decoupled current control has been introduced. The performance of the linear PI controller of the DC-link voltage is strictly dependent on its settings and it may introduce a disadvantageous voltage overshoot under a heavy load impact. In order to improve the transient response of the DC-link voltage control loop a load compensation has been proposed. The different approach to the control of the DC-link voltage based on the regulation of the square power of the DC voltage has been introduced.
Mechanical properties of hybrid fiber reinforced concrete for pavementseSAT Journals
Abstract
The effect of addition of mono fibers and hybrid fibers on the mechanical properties of concrete mixture is studied in the present
investigation. Steel fibers of 1% and polypropylene fibers 0.036% were added individually to the concrete mixture as mono fibers and
then they were added together to form a hybrid fiber reinforced concrete. Mechanical properties such as compressive, split tensile and
flexural strength were determined. The results show that hybrid fibers improve the compressive strength marginally as compared to
mono fibers. Whereas, hybridization improves split tensile strength and flexural strength noticeably.
Keywords:-Hybridization, mono fibers, steel fiber, polypropylene fiber, Improvement in mechanical properties.
Material management in construction – a case studyeSAT Journals
Abstract
The objective of the present study is to understand about all the problems occurring in the company because of improper application
of material management. In construction project operation, often there is a project cost variance in terms of the material, equipments,
manpower, subcontractor, overhead cost, and general condition. Material is the main component in construction projects. Therefore,
if the material management is not properly managed it will create a project cost variance. Project cost can be controlled by taking
corrective actions towards the cost variance. Therefore a methodology is used to diagnose and evaluate the procurement process
involved in material management and launch a continuous improvement was developed and applied. A thorough study was carried
out along with study of cases, surveys and interviews to professionals involved in this area. As a result, a methodology for diagnosis
and improvement was proposed and tested in selected projects. The results obtained show that the main problem of procurement is
related to schedule delays and lack of specified quality for the project. To prevent this situation it is often necessary to dedicate
important resources like money, personnel, time, etc. To monitor and control the process. A great potential for improvement was
detected if state of the art technologies such as, electronic mail, electronic data interchange (EDI), and analysis were applied to the
procurement process. These helped to eliminate the root causes for many types of problems that were detected.
Managing drought short term strategies in semi arid regions a case studyeSAT Journals
Abstract
Drought management needs multidisciplinary action. Interdisciplinary efforts among the experts in various fields of the droughts
prone areas are helpful to achieve tangible and permanent solution for this recurring problem. The Gulbarga district having the total
area around 16, 240 sq.km, and accounts 8.45 per cent of the Karnataka state area. The district has been situated with latitude 17º 19'
60" North and longitude of 76 º 49' 60" east. The district is situated entirely on the Deccan plateau positioned at a height of 300 to
750 m above MSL. Sub-tropical, semi-arid type is one among the drought prone districts of Karnataka State. The drought
management is very important for a district like Gulbarga. In this paper various short term strategies are discussed to mitigate the
drought condition in the district.
Keywords: Drought, South-West monsoon, Semi-Arid, Rainfall, Strategies etc.
Life cycle cost analysis of overlay for an urban road in bangaloreeSAT Journals
Abstract
Pavements are subjected to severe condition of stresses and weathering effects from the day they are constructed and opened to traffic
mainly due to its fatigue behavior and environmental effects. Therefore, pavement rehabilitation is one of the most important
components of entire road systems. This paper highlights the design of concrete pavement with added mono fibers like polypropylene,
steel and hybrid fibres for a widened portion of existing concrete pavement and various overlay alternatives for an existing
bituminous pavement in an urban road in Bangalore. Along with this, Life cycle cost analyses at these sections are done by Net
Present Value (NPV) method to identify the most feasible option. The results show that though the initial cost of construction of
concrete overlay is high, over a period of time it prove to be better than the bituminous overlay considering the whole life cycle cost.
The economic analysis also indicates that, out of the three fibre options, hybrid reinforced concrete would be economical without
compromising the performance of the pavement.
Keywords: - Fatigue, Life cycle cost analysis, Net Present Value method, Overlay, Rehabilitation
Laboratory studies of dense bituminous mixes ii with reclaimed asphalt materialseSAT Journals
Abstract
The issue of growing demand on our nation’s roadways over that past couple of decades, decreasing budgetary funds, and the need to
provide a safe, efficient, and cost effective roadway system has led to a dramatic increase in the need to rehabilitate our existing
pavements and the issue of building sustainable road infrastructure in India. With these emergency of the mentioned needs and this
are today’s burning issue and has become the purpose of the study.
In the present study, the samples of existing bituminous layer materials were collected from NH-48(Devahalli to Hassan) site.The
mixtures were designed by Marshall Method as per Asphalt institute (MS-II) at 20% and 30% Reclaimed Asphalt Pavement (RAP).
RAP material was blended with virgin aggregate such that all specimens tested for the, Dense Bituminous Macadam-II (DBM-II)
gradation as per Ministry of Roads, Transport, and Highways (MoRT&H) and cost analysis were carried out to know the economics.
Laboratory results and analysis showed the use of recycled materials showed significant variability in Marshall Stability, and the
variability increased with the increase in RAP content. The saving can be realized from utilization of recycled materials as per the
methodology, the reduction in the total cost is 19%, 30%, comparing with the virgin mixes.
Keywords: Reclaimed Asphalt Pavement, Marshall Stability, MS-II, Dense Bituminous Macadam-II
Laboratory investigation of expansive soil stabilized with natural inorganic ...eSAT Journals
Abstract
Soil stabilization has proven to be one of the oldest techniques to improve the soil properties. Literature review conducted revealed
that uses of natural inorganic stabilizers are found to be one of the best options for soil stabilization. In this regard an attempt has
been made to evaluate the influence of RBI-81 stabilizer on properties of black cotton soil through laboratory investigations. Black
cotton soil with varying percentages of RBI-81 viz., 0, 0.5, 1, 1.5, 2, and 2.5 percent were studied for moisture density relationships
and strength behaviour of soils. Also the effect of curing period was evaluated as literature review clearly emphasized the strength
gain of soils stabilized with RBI-81 over a period of time. The results obtained shows that the unconfined compressive strength of
specimens treated with RBI-81 increased approximately by 250% for a curing period of 28 days as compared to virgin soil. Further
the CBR value improved approximately by 400%. The studies indicated an increasing trend for soil strength behaviour with
increasing percentage of RBI-81 suggesting its potential applications in soil stabilization.
Influence of reinforcement on the behavior of hollow concrete block masonry p...eSAT Journals
Abstract
Reinforced masonry was developed to exploit the strength potential of masonry and to solve its lack of tensile strength. Experimental
and analytical studies have been carried out to investigate the effect of reinforcement on the behavior of hollow concrete block
masonry prisms under compression and to predict ultimate failure compressive strength. In the numerical program, three dimensional
non-linear finite elements (FE) model based on the micro-modeling approach is developed for both unreinforced and reinforced
masonry prisms using ANSYS (14.5). The proposed FE model uses multi-linear stress-strain relationships to model the non-linear
behavior of hollow concrete block, mortar, and grout. Willam-Warnke’s five parameter failure theory has been adopted to model the
failure of masonry materials. The comparison of the numerical and experimental results indicates that the FE models can successfully
capture the highly nonlinear behavior of the physical specimens and accurately predict their strength and failure mechanisms.
Keywords: Structural masonry, Hollow concrete block prism, grout, Compression failure, Finite element method,
Numerical modeling.
Influence of compaction energy on soil stabilized with chemical stabilizereSAT Journals
Abstract
Increase in traffic along with heavier magnitude of wheel loads cause rapid deterioration in pavements. There is a need to improve
density, strength of soil subgrade and other pavement layers. In this study an attempt is made to improve the properties of locally
available loamy soil using twin approaches viz., i) increasing the compaction of soil and ii) treating the soil with chemical stabilizer.
Laboratory studies are carried out on both untreated and treated soil samples compacted by different compaction efforts. Studies
show that increase in compaction effort results in increase in density of soil. However in soil treated with chemical stabilizer, rate of
increase in density is not significant. The soil treated with chemical stabilizer exhibits improvement in both strength and performance
properties.
Keywords: compaction, density, subgradestabilization, resilient modulus
Geographical information system (gis) for water resources managementeSAT Journals
Abstract
Water resources projects are inherited with overlapping and at times conflicting objectives. These projects are often of varied sizes
ranging from major projects with command areas of millions of hectares to very small projects implemented at the local level. Thus,
in all these projects there is seldom proper coordination which is essential for ensuring collective sustainability.
Integrated watershed development and management is the accepted answer but in turn requires a comprehensive framework that can
enable planning process involving all the stakeholders at different levels and scales is compulsory. Such a unified hydrological
framework is essential to evaluate the cause and effect of all the proposed actions within the drainage basins.
The present paper describes a hydrological framework developed in the form of a Hydrologic Information System (HIS) which is
intended to meet the specific information needs of the various line departments of a typical State connected with water related aspects.
The HIS consist of a hydrologic information database coupled with tools for collating primary and secondary data and tools for
analyzing and visualizing the data and information. The HIS also incorporates hydrological model base for indirect assessment of
various entities of water balance in space and time. The framework would be maintained and updated to reflect fully the most
accurate ground truth data and the infrastructure requirements for planning and management.
Keywords: Hydrological Information System (HIS); WebGIS; Data Model; Web Mapping Services
Forest type mapping of bidar forest division, karnataka using geoinformatics ...eSAT Journals
Abstract
The study demonstrate the potentiality of satellite remote sensing technique for the generation of baseline information on forest types
including tree plantation details in Bidar forest division, Karnataka covering an area of 5814.60Sq.Kms. The Total Area of Bidar
forest division is 5814Sq.Kms analysis of the satellite data in the study area reveals that about 84% of the total area is Covered by
crop land, 1.778% of the area is covered by dry deciduous forest, 1.38 % of mixed plantation, which is very threatening to the
environmental stability of the forest, future plantation site has been mapped. With the use of latest Geo-informatics technology proper
and exact condition of the trees can be observed and necessary precautions can be taken for future plantation works in an appropriate
manner
Keywords:-RS, GIS, GPS, Forest Type, Tree Plantation
Factors influencing compressive strength of geopolymer concreteeSAT Journals
Abstract
To study effects of several factors on the properties of fly ash based geopolymer concrete on the compressive strength and also the
cost comparison with the normal concrete. The test variables were molarities of sodium hydroxide(NaOH) 8M,14M and 16M, ratio of
NaOH to sodium silicate (Na2SiO3) 1, 1.5, 2 and 2.5, alkaline liquid to fly ash ratio 0.35 and 0.40 and replacement of water in
Na2SiO3 solution by 10%, 20% and 30% were used in the present study. The test results indicated that the highest compressive
strength 54 MPa was observed for 16M of NaOH, ratio of NaOH to Na2SiO3 2.5 and alkaline liquid to fly ash ratio of 0.35. Lowest
compressive strength of 27 MPa was observed for 8M of NaOH, ratio of NaOH to Na2SiO3 is 1 and alkaline liquid to fly ash ratio of
0.40. Alkaline liquid to fly ash ratio of 0.35, water replacement of 10% and 30% for 8 and 16 molarity of NaOH and has resulted in
compressive strength of 36 MPa and 20 MPa respectively. Superplasticiser dosage of 2 % by weight of fly ash has given higher
strength in all cases.
Keywords: compressive strength, alkaline liquid, fly ash
Experimental investigation on circular hollow steel columns in filled with li...eSAT Journals
Abstract
Composite Circular hollow Steel tubes with and without GFRP infill for three different grades of Light weight concrete are tested for
ultimate load capacity and axial shortening , under Cyclic loading. Steel tubes are compared for different lengths, cross sections and
thickness. Specimens were tested separately after adopting Taguchi’s L9 (Latin Squares) Orthogonal array in order to save the initial
experimental cost on number of specimens and experimental duration. Analysis was carried out using ANN (Artificial Neural
Network) technique with the assistance of Mini Tab- a statistical soft tool. Comparison for predicted, experimental & ANN output is
obtained from linear regression plots. From this research study, it can be concluded that *Cross sectional area of steel tube has most
significant effect on ultimate load carrying capacity, *as length of steel tube increased- load carrying capacity decreased & *ANN
modeling predicted acceptable results. Thus ANN tool can be utilized for predicting ultimate load carrying capacity for composite
columns.
Keywords: Light weight concrete, GFRP, Artificial Neural Network, Linear Regression, Back propagation, orthogonal
Array, Latin Squares
Experimental behavior of circular hsscfrc filled steel tubular columns under ...eSAT Journals
Abstract
This paper presents an outlook on experimental behavior and a comparison with predicted formula on the behaviour of circular
concentrically loaded self-consolidating fibre reinforced concrete filled steel tube columns (HSSCFRC). Forty-five specimens were
tested. The main parameters varied in the tests are: (1) percentage of fiber (2) tube diameter or width to wall thickness ratio (D/t
from 15 to 25) (3) L/d ratio from 2.97 to 7.04 the results from these predictions were compared with the experimental data. The
experimental results) were also validated in this study.
Keywords: Self-compacting concrete; Concrete-filled steel tube; axial load behavior; Ultimate capacity.
Evaluation of punching shear in flat slabseSAT Journals
Abstract
Flat-slab construction has been widely used in construction today because of many advantages that it offers. The basic philosophy in
the design of flat slab is to consider only gravity forces; this method ignores the effect of punching shear due to unbalanced moments
at the slab column junction which is critical. An attempt has been made to generate generalized design sheets which accounts both
punching shear due to gravity loads and unbalanced moments for cases (a) interior column; (b) edge column (bending perpendicular
to shorter edge); (c) edge column (bending parallel to shorter edge); (d) corner column. These design sheets are prepared as per
codal provisions of IS 456-2000. These design sheets will be helpful in calculating the shear reinforcement to be provided at the
critical section which is ignored in many design offices. Apart from its usefulness in evaluating punching shear and the necessary
shear reinforcement, the design sheets developed will enable the designer to fix the depth of flat slab during the initial phase of the
design.
Keywords: Flat slabs, punching shear, unbalanced moment.
Evaluation of performance of intake tower dam for recent earthquake in indiaeSAT Journals
Abstract
Intake towers are typically tall, hollow, reinforced concrete structures and form entrance to reservoir outlet works. A parametric
study on dynamic behavior of circular cylindrical towers can be carried out to study the effect of depth of submergence, wall thickness
and slenderness ratio, and also effect on tower considering dynamic analysis for time history function of different soil condition and
by Goyal and Chopra accounting interaction effects of added hydrodynamic mass of surrounding and inside water in intake tower of
dam
Key words: Hydrodynamic mass, Depth of submergence, Reservoir, Time history analysis,
Evaluation of operational efficiency of urban road network using travel time ...eSAT Journals
Abstract
Efficiency of the road network system is analyzed by travel time reliability measures. The study overlooks on an important measure of
travel time reliability and prioritizing Tiruchirappalli road network. Traffic volume and travel time were collected using license plate
matching method. Travel time measures were estimated from average travel time and 95th travel time. Effect of non-motorized vehicle
on efficiency of road system was evaluated. Relation between buffer time index and traffic volume was created. Travel time model has
been developed and travel time measure was validated. Then service quality of road sections in network were graded based on
travel time reliability measures.
Keywords: Buffer Time Index (BTI); Average Travel Time (ATT); Travel Time Reliability (TTR); Buffer Time (BT).
Estimation of surface runoff in nallur amanikere watershed using scs cn methodeSAT Journals
Abstract
The development of watershed aims at productive utilization of all the available natural resources in the entire area extending from
ridge line to stream outlet. The per capita availability of land for cultivation has been decreasing over the years. Therefore, water and
the related land resources must be developed, utilized and managed in an integrated and comprehensive manner. Remote sensing and
GIS techniques are being increasingly used for planning, management and development of natural resources. The study area, Nallur
Amanikere watershed geographically lies between 110 38’ and 110 52’ N latitude and 760 30’ and 760 50’ E longitude with an area of
415.68 Sq. km. The thematic layers such as land use/land cover and soil maps were derived from remotely sensed data and overlayed
through ArcGIS software to assign the curve number on polygon wise. The daily rainfall data of six rain gauge stations in and around
the watershed (2001-2011) was used to estimate the daily runoff from the watershed using Soil Conservation Service - Curve Number
(SCS-CN) method. The runoff estimated from the SCS-CN model was then used to know the variation of runoff potential with different
land use/land cover and with different soil conditions.
Keywords: Watershed, Nallur watershed, Surface runoff, Rainfall-Runoff, SCS-CN, Remote Sensing, GIS.
Estimation of morphometric parameters and runoff using rs & gis techniqueseSAT Journals
Abstract
Land and water are the two vital natural resources, the optimal management of these resources with minimum adverse environmental
impact are essential not only for sustainable development but also for human survival. Satellite remote sensing with geographic
information system has a pragmatic approach to map and generate spatial input layers of predicting response behavior and yield of
watershed. Hence, in the present study an attempt has been made to understand the hydrological process of the catchment at the
watershed level by drawing the inferences from moprhometric analysis and runoff. The study area chosen for the present study is
Yagachi catchment situated in Chickamaglur and Hassan district lies geographically at a longitude 75⁰52’08.77”E and
13⁰10’50.77”N latitude. It covers an area of 559.493 Sq.km. Morphometric analysis is carried out to estimate morphometric
parameters at Micro-watershed to understand the hydrological response of the catchment at the Micro-watershed level. Daily runoff
is estimated using USDA SCS curve number model for a period of 10 years from 2001 to 2010. The rainfall runoff relationship of the
study shows there is a positive correlation.
Keywords: morphometric analysis, runoff, remote sensing and GIS, SCS - method
-
Effect of variation of plastic hinge length on the results of non linear anal...eSAT Journals
Abstract The nonlinear Static procedure also well known as pushover analysis is method where in monotonically increasing loads are applied to the structure till the structure is unable to resist any further load. It is a popular tool for seismic performance evaluation of existing and new structures. In literature lot of research has been carried out on conventional pushover analysis and after knowing deficiency efforts have been made to improve it. But actual test results to verify the analytically obtained pushover results are rarely available. It has been found that some amount of variation is always expected to exist in seismic demand prediction of pushover analysis. Initial study is carried out by considering user defined hinge properties and default hinge length. Attempt is being made to assess the variation of pushover analysis results by considering user defined hinge properties and various hinge length formulations available in literature and results compared with experimentally obtained results based on test carried out on a G+2 storied RCC framed structure. For the present study two geometric models viz bare frame and rigid frame model is considered and it is found that the results of pushover analysis are very sensitive to geometric model and hinge length adopted. Keywords: Pushover analysis, Base shear, Displacement, hinge length, moment curvature analysis
Effect of use of recycled materials on indirect tensile strength of asphalt c...eSAT Journals
Abstract
Depletion of natural resources and aggregate quarries for the road construction is a serious problem to procure materials. Hence
recycling or reuse of material is beneficial. On emphasizing development in sustainable construction in the present era, recycling of
asphalt pavements is one of the effective and proven rehabilitation processes. For the laboratory investigations reclaimed asphalt
pavement (RAP) from NH-4 and crumb rubber modified binder (CRMB-55) was used. Foundry waste was used as a replacement to
conventional filler. Laboratory tests were conducted on asphalt concrete mixes with 30, 40, 50, and 60 percent replacement with RAP.
These test results were compared with conventional mixes and asphalt concrete mixes with complete binder extracted RAP
aggregates. Mix design was carried out by Marshall Method. The Marshall Tests indicated highest stability values for asphalt
concrete (AC) mixes with 60% RAP. The optimum binder content (OBC) decreased with increased in RAP in AC mixes. The Indirect
Tensile Strength (ITS) for AC mixes with RAP also was found to be higher when compared to conventional AC mixes at 300C.
Keywords: Reclaimed asphalt pavement, Foundry waste, Recycling, Marshall Stability, Indirect tensile strength.
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About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
AKS UNIVERSITY Satna Final Year Project By OM Hardaha.pdf
Analysis of symmetrical & asymmetrical pwm based three phase ac to ac converter for power quality improvement
1. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
_______________________________________________________________________________________________
Volume: 05 Issue: 08 | Aug-2016, Available @ http://ijret.esatjournals.org 332
ANALYSIS OF SYMMETRICAL & ASYMMETRICAL PWM BASED
THREE PHASE AC TO AC CONVERTER FOR POWER QUALITY
IMPROVEMENT
Venkatesha K1, Vidya H A2
1
Associate Professor, Dept. of Electrical & Electronics Engineering, BNM Institute of Technology, Karnataka,
Bangalore, India
2
Professor & HOD, Dept. of Electrical & Electronics Engineering, Global Academy of Technology, Karnataka,
Bangalore, India
Abstract
A Three phase bidirectional AC to AC buck convertercircuit using power MOSFET operating in high frequency chopping mode is
simulated and analyzed for electrical parameters such as output phase voltage, input line current, input power factor, harmonic
profile and efficiency using MATLAB/simulink software package. The various PWM techniques such as symmetrical ramp-DC
PWM (SRDPWM), asymmetrical ramp-triangular PWM (ARTPWM), asymmetrical sinusoidal PWM type-1 [ASPWM1] and
asymmetrical sinusoidal PWM type-2 [ASPWM2] techniques are adopted to analyze the harmonic profile, input power factor and
efficiency of the converter. The rms value of the output phase voltage, output line current and source current can be significantly
increased by varying the duty ratio K in case of symmetrical PWM control strategy and modulation index MI in case of
asymmetrical PWM control strategies independent of variation in switching frequency. It is observed from the simulation resu lts
that the ASPWM1 switching strategy gives more output phase voltage, input power factor, efficiency by increasing modulation
index MI and reduced low order harmonics of output voltage and source current by increasing the number of pulses per half
cycle P compared to other PWM techniques rendering easy and economical filteration.
Keywords: Three phase AC chopper, symmetrical ramp-DC PWM, asymmetrical ramp-triangular PWM,
asymmetrical sinusoidal PWM technique, harmonic profile, power factor, efficiency
---------------------------------------------------------------------***---------------------------------------------------------------------
1. INTRODUCTION
Industrial loads such as heaters, illumination control,
furnaces, AC motor speed control and also theatre dimmers
uses AC voltage controllers. Such voltage regulators,
however, have slow response, poor input power factor, and
high magnitude of low order harmonic at both input and
output sides.These converters need large input-output filters
to reduce low order harmonics in the line current. These
drawbacks have been overcome by designing various
topologies of AC chopper [1-8]. In most standard AC
choppers, the commutation causes high voltage spikes and
an alternative current path has to be provided when current
paths are changed. This alternative current path is
implemented using additional bidirectional switches [3].
Such topologies are difficult and expensive to realize and
the voltage stress of the switch is also high, resulting in
reduced reliability.
The harmonic analysis and power factor improvement are
the two important parameters to be considered in AC to AC
converter circuits [9]. It is required to select the modern
PWM technique which gives best performance of the
converter with respect to improved input power factor and
reduced harmonic content in both input current & output
voltages. In this paper, a three phase bidirectional AC buck
converter is proposed and analyzed for three phase star
connected RL load using symmetrical ramp-DC PWM
(SRDPWM), asymmetrical ramp-triangular PWM
(ARTPWM), asymmetrical sinusoidal PWM type-1
[ASPWM1] and asymmetrical sinusoidal PWM type-2
[ASPWM2] techniques. In case of SRDPWM technique,
duty ratio K is varied in order to vary the power flow, better
harmonic profile and efficiency of the three phase converter.
Whereas in case of ARTPWM, ASPWM1 and ASPWM2
technique, the modulation index MI is varied in order to
change the power flow, harmonic profile, power factor and
efficiency of the three phase convert. But the number of
pulses per half cycle (P) is increased in both symmetrical
and asymmetrical PWM techniques in order to change the
entire harmonic profile of the output phase voltage and input
source current. The change in switching frequency has no
effect on output phase voltage, output line current and
source current variation in both symmetrical and
asymmetrical control strategies.
2. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 05 Issue: 08 | Aug-2016, Available @ http://ijret.esatjournals.org 333
2. OPERATION OF THE CONVERTER
TOPOLOGY
Fig. 1 Block diagram of three phase AC to AC converter
Fig.1 shows the block diagram of three phase AC to AC
buck converter with control circuit to generate pulses to
power MOSFET embedded four quadrant switches
operating in high frequency chopping mode. The control
circuit comprises of comparator that compares carrier
signals such as ramp or triangular signal with control or
reference signals such as DC, negative ramp and sine wave
signals. The carrier wave remains same for all the three
phases. But three reference waves which are 120o apart are
taken to compare with common carrier waveform in order to
generate the PWM pulses. The logical operation takes place
between PWM pulses and zero crossing detector pulses
which are tapped from three phase supply in order to
generate switching pulses to trigger the particular switching
set during positive and negative half cycles respectively.
The duty ratio K can be increased in order to vary all the
electrical parameters including harmonic profile. Whereas P
can be varied in order to vary the harmonic profile of the
converter. The technique continues to evoke interest with
respect to variation of P and K [8]. The chopped output
voltage waveform is analyzed for harmonic content for
various values of P & K. This technique can be adopted for
the harmonic content reduction at the high frequency
chopping mode facilitating easy filtration at lower cost.
Fig. 2 shows the three phase Buck AC chopper that uses
four quadrant bidirectional switches. The combination of
switches M1 with series diode D1 and M4 with series diode
D4 forms one set of four quadrant switch for modulating
purpose. Similarly the switch combination M8 with series
diode D8 and M7 with series diode D7 forms another four
quadrant switch set for freewheeling operation across RL
loads of phase ‘A’.
The control of the switches is based on the different modern
PWM techniques. In practical realizations of the converter,
stray inductances increase the voltage stress of the
bidirectional switches and may destroy the switches. This
situation requires the converter using AC snubber
comprising RC combination (Rs and Cs).
The configuration of the three phase buck ac chopper
feeding star connected RL load involves regeneration,
power absorption by the load and freewheeling. Each switch
conducts for 180 degrees. At any instant of time, three
switches are modulated and three switches are additionally
turned on for regeneration or freewheeling operation. The
commutation policy is that the switches M2, M3 and M4 for
Vs > 0 are additionally turned on for 60 degrees during
which switch M1 is modulated. The modulating signal
changes for every 60 degrees so that at any instant three
switches will conduct. The switching pattern is 5-6-1, 6-1-2,
1-2-3, 2-3-4, 3-4-5, 4-5-6 and back to 5-6-1 after one cycle.
The other switches are additionally turned on for giving path
for an inductor current. If the load inductor current iL is
positive, the inductor current is bypassed or freewheeled
through freewheeling switches available in parallel to the
load. If the load inductor current is negative, then it
bypasses to the source through the input side switches. The
enhancement type MOFSETs are used in converters as
switching devices due to their high switching frequency
greater than 1MHz, and is available with forward blocking
voltage and current of 1000V and 40A respectively. The
operation of power switching devices at higher frequencies
results in decreased size of inductors and filter capacitors
that facilitates compact and economical power electronic
systems. Fig. 3 shows the switching pattern for the four
forced commutated switches of the three phase buck AC
chopper. The dead-time is requisite to avoid current spikes
of practical non-ideal switches and at the same time a
current path of the inductive load has to be provided to
avoid voltage spikes. The modulating pulses can be
symmetrical or asymmetrical which depends on the type of
PWM technique. But the logical operation remains same for
all the PWM techniques.
3. MERITS OF AC TO AC CONVERTER
CIRCUITS
The merits of AC to AC converter circuit are the reduced
lower order harmonics at both input and output side.
Sinusoidal input currents with nearly unity input power
factor can be achieved with the help of input filters.
Sinusoidal output currents with RL loads without filters. The
higher switching frequency selection results in reduction of
filter size. AC chopper does not require gating signals
synchronous with the line voltage. Faster dynamic response
with respect to sag and swell correction and high efficiency
of the converter can be achieved.
3. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 05 Issue: 08 | Aug-2016, Available @ http://ijret.esatjournals.org 334
Fig. 2 Three phase buck converter circuit diagram for three phase star connected RL load
Fig. 3a Switching pattern for the line MOSFET switches M1 to M6 of three phase buck converter
4. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 05 Issue: 08 | Aug-2016, Available @ http://ijret.esatjournals.org 335
Fig. 3b Switching pattern for load side MOSFET switches M7 to M12 of three phase star connected load.
4. VARIOUS PWM SWITCHING PATTERNS
The various PWM switching techniques selected for AC
chopper are analyzed for input power factor, harmonic
profile and efficiency of the converter circuit.
4.1 Symmetrical Ramp-DC PWM (SRDPWM)
In the SRDPWM control strategy as shown in Fig.4, the
switching pulses are generated by comparing ramp with DC
voltage. The carrier signal ramp having peak value of 10Vis
varied for different switching frequencies like 4.2 KHz,
4.8 KHz, 5.4 KHZ and 6 KHz. The DC reference or control
signal is varied from 4V to 9V in order to get duty ratio
from 0.4 to 0.9. The control circuit comprises of ramp pulse
generator of desired frequency which is compared with the
variable DC voltage Vcontrol to generate switching pulses.
The ZCD pulses are obtained by stepping down the three
phase voltages and then passed through the zero crossing
detectors. The PWM pulses and ZCD pulses of phases A, B
& C are ORed to generate switching pulses for six switches
of the three phase converter as shown in Fig. 3a. The ZCD
and inverted ZCD pulses are fed to the freewheeling
switches connected across the RL load as shown in Fig. 3b.
The number of pulses per half cycle P can be calculated as
𝑃 =
𝐹𝑠
2𝐹
(1)
The duty ratio is defined as
𝐾 =
𝑡 𝑜𝑛
𝑇 𝑠
(2)
Where
Fs : Switching frequency in Hz.
F : Fundamental or supply frequency n Hz
ton: On time of switching pulses in secs.
Ts : Total Switching time in secs.
Fig.4 SRDPWM technique and the corresponding switching
pulses
5. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 05 Issue: 08 | Aug-2016, Available @ http://ijret.esatjournals.org 336
4.2 Asymmetrical Ramp-Triangular PWM
(ARTPWM)
In the ARTPWM control strategy of a three phase ac
chopper, the switching pulses are generated by comparing
three different negative slope ramps which are electrically
displace by 120o with common triangular carrier signal in
order to generate the pulses. The peak to peak value of
triangular waveform is 20V. The ZCD pulses are obtained
by stepping down the three phase voltages and then passed
through the zero crossing detectors. The PWM pulses and
ZCD pulses are ORed to generate switching pulses for six
switches of the three phase converter. The ZCD and inverted
ZCD pulses are fed to the freewheeling diodes that are
connected across the RL load. The triangular waveform is
varied for different switching frequencies like 4.2 KHz, 4.8
KHz, 5.4 KHZ and 6 KHz. The negative ramp signal peak
value is varied from 4V to 9V with different slopes in order
to vary the MI in linear region from 0.4 to 0.9. The ratio of
peak value of ramp to the peak value of triangular signal is
named as modulation index MI. The definition of
modulation index is
MI =
Vramp−peak
Vtri−peak
(3)
Fig.5 ARTPWM technique and the corresponding switching
pulses
4.3 Asymmetrical Sinusoidal PWM type-1
[ASPWM1]
In the ASPWM1 control strategy of a three phase ac
chopper, the switching pulses are generated by comparing
three different unidirectional AC signal [displaced by 120o]
with triangular signal as shown in Fig.6. The peak to peak
value of triangular waveform is 20V. The ZCD pulses are
obtained by stepping down the three phase voltages and then
passed through the zero crossing detectors.The PWM pulses
and ZCD pulses are ORed to generate switching pulses for
six switches of the three phase converter. The ZCD and
inverted ZCD pulses are fed to the freewheeling switches
connected across the RL load as shown in Fig. 3b. The
triangular waveform is varied for different switching
frequencies like 4.2 KHz, 4.8 KHz, 5.4 KHZ and 6 KHz.
The control signal sine wave peak value is varied from 4V
to 9V in order to vary the MI in linear region from 0.4 to
0.9. The ratio of peak value of sine wave to the peak value
of triangular signal is named as modulation index MI. The
definition of modulation index is
𝑀𝐼 =
𝑉 𝑠𝑖𝑛𝑒−𝑝𝑒𝑎𝑘
𝑉 𝑡𝑟𝑖−𝑝𝑒𝑎𝑘
(4)
Fig.6
ASPWM1 technique and the corresponding switching pulses
4.4 Asymmetrical Sinusoidal PWM type2
[ASPWM2]
In the ASPWM2 control strategy of a three phase ac
chopper, the switching pulses are generated by comparing
unidirectional AC signal with positive triangular signal
whose peak value is 10V as shown in Fig.7. The peak value
of control signal which is unidirectional sine wave is varied
from 4V to 9V in order to vary MI in linear region from 0.4
to 0.9. The ZCD pulses are obtained by stepping down the
three phase voltages and then passed through the zero
crossing detectors. The PWM pulses and ZCD pulses are
ORed to generate switching pulses for six switches of the
three phase converter. The ZCD and inverted ZCD pulses
are fed to freewheeling switches that are connected across
RL load as shown in Fig. 3b. The ratio of peak value of sine
wave to the triangular signal is named as modulation index
MI. The definition of modulation index is
𝑀𝐼 =
𝑉 𝑠𝑖𝑛𝑒−𝑝𝑒𝑎𝑘
𝑉 𝑡𝑟𝑖−𝑝𝑒𝑎𝑘
(5)
Fig.7 ASPWM2 technique and the corresponding switching
pulses
6. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 05 Issue: 08 | Aug-2016, Available @ http://ijret.esatjournals.org 337
5. SIMULATION OF AC TO AC CONVERTER CIRCUIT
Fig. 8 Simulation circuit of three phase AC to AC converter built using MATLAB/simulink software package.
The Harmonic profile, input power factor and efficiency of
the three phase converter is investigated using
MATLAB/simulink. The three phase buck AC chopper with
AC snubber simulation model is as shown in Fig. 8. The
system characteristics are input line voltage VL= 400 V,
50Hz supply, semiconductor element MOSFET IRFPE40,
snubber elements Rs=5.4K & Cs=3nF, load parameters are
Ro=529 Lo=0.9H. The Switching frequency Fs is varied
from 4.2 KHz to 6 KHz and corresponding P is varied from
42 to 60 pulses per half cycle which is related as given in
equation (1). The harmonic order up to 100th order is
considered in the analysis. The harmonic components
present in the source current and output phase voltage are
dependent on P as nP 1. Where n is an even number. For
instance, if P=42 [Fs=4.2HZ], then the order of the
harmonics present are 2P 1, 4P 1 etc [harmonic order 83,
85, 167, 169]. In this way selective harmonic elimination
can be done by selecting the proper value of P. Therefore for
P=42, harmonic order up to 82nd order can be eliminated in
the output phase voltage and source current.
The input side parameters like input phase voltage, source
current are sensed to calculate input side rms values, input
power factor and input power using sub models. Similarly
output side parameters like output phase voltage and current
are sensed to calculate their rms values, output power and
power factor by using sub models. Hence, the power factor
PF is modeled using the general definition as given in
equation (6).
Using all these parameters, the efficiency of the three phase
balanced converter can be calculated as per equation (7)
using sub models and displayed using numeric displays.
𝑃𝐹 =
𝑃s
s
=
𝑃s
𝑉𝑟𝑚s 𝐼 𝑟𝑚s
=
1
T
∫ vs
(t)is
(t)dt
T
0
√
1
T
∫ v2
s
(t)dt
T
0
√
1
T
∫ i2
s
(t)dt
T
0
(6)
The efficiency can be calculated as
7. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 05 Issue: 08 | Aug-2016, Available @ http://ijret.esatjournals.org 338
=
Po
Ps
=
1
T
∫ vo
(t)io
(t)dt
T
0
1
T
∫ vs
(t)is
(t)dt
T
0
(7)
Fig.9 Waveforms of three phase output voltage for duty
ratio K=0.5 and P=60 [Fs=6 KHz]
Fig.9 shows the waveforms of output phase voltages Van,
Vbn and Vcn using SRDPWM switching pattern. The output
line currents IA, IB and IC are sinusoidal in nature for
inductive load as shown in Fig. 10. In this case freewheeling
operation is considered and proper path is provided for
inductive load current irrespective of positive or negative
value by turning on the additional switches. The output
current is almost a sine wave without ripple content due to
freewheeling operation of inductive load. For Vs >0, the
positive inductive load current passes through freewheeling
bidirectional switches and negative inductive load current
passes through the source.
Fig.10 Waveforms of three phase output currents for P=60
[Fs=6 KHz]
Fig.11 Plot of output phase voltage Van versus duty ratio for
different switching frequency using SRDPWM technique
Fig.12 Plot of THD(Van) output phase voltage versus duty
ratio K for different switching frequency using SRDPWM
technique
Fig.11 indicates the plot of output phase voltage Van with
respect to the variation of duty ratio K. It is observed that
the output phase voltage Van remains same irrespective of
the switching frequency variation. The harmonic profile
changes with the increase in duty ratio as shown in Fig. 12.
The THD(Van) predominantly reduces with respect to
increase in number of pulses per half cycle P or switching
frequency Fs. For instance, selecting P=60 or Fs=6 KHz in
SRDPWM technique, up to 119th harmonic order are
eliminated and hence the THD(Vo) at K=0.9 is 2.57%. But
as the switching frequency is increased, the efficiency of the
converter decreases due to switching losses as shown in
Fig.13. The characteristics of these plots are similar in all
the PWM techniques.
Fig.13 Plot of efficiency versus duty ratio K for different
switching frequency using SRDPWM technique
c
8. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Fig.14 & Fig.15 indicates the harmonic profile of various
PWM switching patterns at switching frequency Fs=6KHz.
The THD of the output phase voltage is maximumin case of
ASPMW2 type [THD(Vo)=20.5% for K=0.4 to 18.5% for
K=0.9] and minimum in case of SRDPWM technique
[THD(Vo)=11.11% for K=0.4 to 2.57% for K=0.9].
Similarly The THD of the source current is maximum in
case of ASPMW2 type [THD(Is)=26.73% for K=0.4 to
29.08% for K=0.9] and minimum in case of SRDPWM
technique [THD(Is)=13.52% for K=0.4 to 5.24% for K=0.9].
The ARTPWM and ASPMW1 techniques are better than the
ASPMW2 technique with respect to THD of output voltage
and source current variation. These techniques have better
harmonic profile from K=0.4 to 0.6. But there is almost
constant or slight increase in THD values with respect to
variation of MI in these cases. Hence SRDPWM technique
is better with respect to harmonic profile than other
techniques with respect to variation of duty cycle K=0.6
onwards.
Fig.14 Plot of THD(Van) versus duty ratio for different
PWM technique with constant switching frequency of 6KHz
Fig.15 Plot of THD(Is) input line current versus duty ratio K
for different PWM technique with constant switching
frequency of 6KHz
Table-1 Analysis of power factor and efficiency with respect to duty ratio/MI for different PWM techniques
Table-1 indicates that the input power factor of the three
phase converter is more in case of ASPMW1 technique
[PF=0.76 to 0.86] for the variation of MI from 0.4 to 0.9.
Even though harmonic profile is better in case of SRDPWM
technique, since the input power factor is more in case of
ASPMW1 technique, the overall efficiency of the converter
is better using this technique. Therefore it is required to
consider both harmonic profile and power factor in order to
observe the overall efficiency of the three phase converter.
Hence ASPWM1 technique is being recommended for this
converter for better input power factor and efficiency of the
converter.
6. CONCLUSION
A three phase bidirectional AC to AC buck converter is
simulated and analyzed for electrical parameters such as
output phase voltage, input current, input power factor,
harmonic profile and efficiency using MATLAB/simulink
software package. The various PWM techniques such as
SRDPWM, ARTPWM, ASPWM1 and ASPWM2
techniques are adopted to analyze the three phase buck
converter behavior. The rms value of the output phase
voltage, output current and source current can be
significantly increased by varying the duty ratio Kin case of
symmetrical PWM control strategy and modulation index
MI in case of asymmetrical PWM control strategies
independent of variation in switching frequency. It is
observed from the simulation results that the ASPWM1
switching strategy gives more output phase voltage, input
power factor, efficiency by increasing MI and reduced low
order harmonics of output phase voltage and source current
by increasing the number of pulses per half cycle P or
switching frequency compared to other PWM techniques
rendering easy and economical filteration.
9. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 05 Issue: 08 | Aug-2016, Available @ http://ijret.esatjournals.org 340
ACKNOWLEDGEMENT
The authors wish to thank the BNM Institute of Technology
& its R&D centre in Electrical & Electronics Department for
providing lab facility in simulating and analyzing proposed
three phase bidirectional Buck AC converter for power
quality improvement.
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BIOGRAPHIES
Venkatesha. K received his B.E.
degree in Electrical and Electronics
Engineering and the M.E. in Power
electronics from Bangalore University,
Bangalore in 1997 and 2005
respectively. He has secured First rank
in M.E from Bangalore University. He worked as a Lecturer
for Golden Valley College of engineering, Kolar Gold
Fields from 2000 to 2004. He is currently working as an
Associate Professor in BNM institute of Technology,
Bengaluru. He is pursuing PhD in BNMIT R&D centre
under Visvesvaraya Technological University, Belgaum. His
research interests are in the areas of Power Electronics and
Power Quality.
Vidya H.A received her B.E. degree in
Electrical and Electronics Engineering
from Mysore University, Mysore and
the M.Tech. in Computer Application in
Industrial Drives from Visvesvaraya
Technological University, Belgaum in
1996 and 2001 respectively. She has
secured First rank in M.Tech from
Visvesvaraya Technological University. She has completed
her PhD in electrical sciences in 2008 from M.S. Ramaiah
R&D centre under VTU. From 1997 to 2003, she worked as
a Lecturer in KVG College of Engineering, Sullia. She
worked at various capacities in BNM Institute of
Technology, Bengaluru from 2003 to 2015. Currently she is
heading the Department of Electrical & Electronics
Engineering, Global academy of technology, Bengaluru. Her
research interests are in the areas of Signal Processing, High
Voltage and Power Quality.