This paper proposes a set of design techniques to build a DC-DC converter for the interconnection of different sources of renewable energy with storage elements and flexible load profiles. This type of multifunctional DC-DC converter is essential to provide the dispatch of energy generation to storage connected to the DC bus or allow energy exchange with the AC network, with different decision modes as a function of the state of charge of batteries, with the forecast of the consumption of a house with renewable production. This work emphasizes the application of a method to design switched mode flyback converters with current control capabilities on the output side.
SRF CONTROLLED DVR FOR COMPENSATION OF BALANCED AND UNBALANCED VOLTAGE DISTUR...IAEME Publication
The growth of power electronictechnology in the field of electric power sector has caused a greater awarenesson the power quality of distribution systems. With the re-structuring of powersystems and with shifting trend towards distributed and dispersed generation,the issue of power quality is going to take newer dimensions. The presentresearch is to identify the prominent concerns in this area and hence themeasures that can enhance the quality of power. This paper investigates theproblems of voltage sag, swell and its severe impact on nonlinear loads,sensitive loads.
NON-ISOLATED SOFT SWITCHING DC-DC CONVERTER AND LOAD AT FULL RANGE OF ZVS IAEME Publication
A non isolated soft switching DC–DC converter and load at full range of zero-voltage
switching (ZVS) characteristic is proposed. The proposed converter consists of an auxiliary circuit,
an inductor, two switches, and 2 diodes to achieving high efficiency at full range of load. At low
and heavy loads, ZVS of switching device is achieved by energy storing component. The inductor
energy stored varies with load and hence results in minimizes conduction loss. This leads to
switching of device for full range of load. The proposed DC - DC converter achieves high
efficiency as switching loss is reduced due to soft switching and ZVS operation which severe to
reduce conduction loss. The efficiency is improved about 4% in boost mode (2.5% in buck mode) at
full range of load. To verify the performance of the proposed converter, experimental results
prototype are presented.
Brushless DC motor is a synchronous machine that makes use of electronic commutation instead of mechanical commutator. Brushless DC motors makes use of inverter encompassing static switches for its operation. A simple bridge converter when used for BLDC drive as front end converter makes input source power factor to get reduced which is unacceptable in the power system. To avoid the distortions in the source voltage and source currents, Buck converter which was used as power factor correction (PFC) converter in this paper to improve the power factor. Presence of power electronic converters deteriorates system power factor effecting overall system performance. This paper presents buck converter for power factor correction in brushless DC motor drive system. Buck converter is operated with current control strategy rather to conventional voltage follower control. Simulation model was obtained using MATLAB/SIMULINK software and the brushless DC motor performance characteristics were shown for conditions with different DC link voltages and step variation in DC link voltage. Total harmonic distortion in source current was also presented.
One of the preferred choices of electronic power conversion for high power applications are multilevel inverters topologies finding increased attention in industry. Cascaded H-Bridge multilevel inverter is one of these topologies reaching the higher output voltage, power level and higher reliability due to its modular topology. Level Shifted Carrier Pulse Width Modulation (LSCPWM) and Phase Shifted Carrier Pulse Width Modulation are used generally for switching cascaded H-bridge (CHB) multilevel inverters. This paper compares LSCPWM and PSCPWM in terms of total harmonics distortion (THD) and output voltage among inverter cells. Simulation for 21-level CHB inverter is carried out in MATLAB/SIMULINK and simulation results are presented.
SRF CONTROLLED DVR FOR COMPENSATION OF BALANCED AND UNBALANCED VOLTAGE DISTUR...IAEME Publication
The growth of power electronictechnology in the field of electric power sector has caused a greater awarenesson the power quality of distribution systems. With the re-structuring of powersystems and with shifting trend towards distributed and dispersed generation,the issue of power quality is going to take newer dimensions. The presentresearch is to identify the prominent concerns in this area and hence themeasures that can enhance the quality of power. This paper investigates theproblems of voltage sag, swell and its severe impact on nonlinear loads,sensitive loads.
NON-ISOLATED SOFT SWITCHING DC-DC CONVERTER AND LOAD AT FULL RANGE OF ZVS IAEME Publication
A non isolated soft switching DC–DC converter and load at full range of zero-voltage
switching (ZVS) characteristic is proposed. The proposed converter consists of an auxiliary circuit,
an inductor, two switches, and 2 diodes to achieving high efficiency at full range of load. At low
and heavy loads, ZVS of switching device is achieved by energy storing component. The inductor
energy stored varies with load and hence results in minimizes conduction loss. This leads to
switching of device for full range of load. The proposed DC - DC converter achieves high
efficiency as switching loss is reduced due to soft switching and ZVS operation which severe to
reduce conduction loss. The efficiency is improved about 4% in boost mode (2.5% in buck mode) at
full range of load. To verify the performance of the proposed converter, experimental results
prototype are presented.
Brushless DC motor is a synchronous machine that makes use of electronic commutation instead of mechanical commutator. Brushless DC motors makes use of inverter encompassing static switches for its operation. A simple bridge converter when used for BLDC drive as front end converter makes input source power factor to get reduced which is unacceptable in the power system. To avoid the distortions in the source voltage and source currents, Buck converter which was used as power factor correction (PFC) converter in this paper to improve the power factor. Presence of power electronic converters deteriorates system power factor effecting overall system performance. This paper presents buck converter for power factor correction in brushless DC motor drive system. Buck converter is operated with current control strategy rather to conventional voltage follower control. Simulation model was obtained using MATLAB/SIMULINK software and the brushless DC motor performance characteristics were shown for conditions with different DC link voltages and step variation in DC link voltage. Total harmonic distortion in source current was also presented.
One of the preferred choices of electronic power conversion for high power applications are multilevel inverters topologies finding increased attention in industry. Cascaded H-Bridge multilevel inverter is one of these topologies reaching the higher output voltage, power level and higher reliability due to its modular topology. Level Shifted Carrier Pulse Width Modulation (LSCPWM) and Phase Shifted Carrier Pulse Width Modulation are used generally for switching cascaded H-bridge (CHB) multilevel inverters. This paper compares LSCPWM and PSCPWM in terms of total harmonics distortion (THD) and output voltage among inverter cells. Simulation for 21-level CHB inverter is carried out in MATLAB/SIMULINK and simulation results are presented.
Nowadays power electronics circuits are embedded to most of electrical application areas. This approached offers a great control mechanism with simple and easy circuit configuration. Switched Reluctance Motor (SRM) is one of the most recent apparatus which draws a great number of researchers’ interests. Previously several attempts are made to use the power converters as driver for SRM such as Voltage Source Inverter (VSI) and bridge converters. This paper presents an analysis study of three level inverter to control the SRM. The inverter is controlled using space vector modulation SVM. The aim of this paper is to report the use the multilevel inverter to be fed into the SRM. The implementation of the multilevel inverter is abl to reduce the Total Harmonics Distortion (THD). Performance comparison are made between the multilevel and previous power electronics circuits that applied to the SRM. The simulation results have been conducted by MATLAB/SIMULINK software.
Fuzzy based control of Transformer less Coupled inductor based DC-DC converterIJERA Editor
Most of the industrial applications use any one of the basic DC-DC converter configurations namely buck,
boost, buck–boost, and Cuk converters. These converters are non-isolating converters. Buck-boost converters
use inductors for storing energy from the source and release the same to load or output. This results in high
stress across magnetic components. This drawback restricts usage of buck-boost converters to low power
applications. Flyback converters popularly have known as buck-boost converters uses transformers for
achieving wide range of step down and step up voltages. Coupled inductor based converters or tapped inductor
based converters are used for achieving wide input – wide output conversion ratios. Coherent transition between
step-down and step-up modes is achieved by a proper control scheme. This paper proposes fuzzy logic based
closed loop control scheme for control of converter switches. Theoretical derivations of control parameters with
their membership values, mamdani based rules for development of fuzzy rules and simulation results of a
coupled inductor based DC-DC converter using MATLAB / SIMULINK are concluded.
Single Phase Matrix Converter for Input Power Factor Improvementiosrjce
IOSR Journal of Electrical and Electronics Engineering(IOSR-JEEE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of electrical and electronics engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electrical and electronics engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Pi controller based of multi level upqc using dq0 transformation to improve 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.
Close Loop Control of Induction Motor Using Z-Source InverterIJSRD
In this paper a new closed loop control of induction motor fed by a Z – source inverter based on the vector control or field oriented control strategy is presented. Induction motor is supplied by Z – source inverter, in the Z – source inverter the term Z denotes impedance which means a combination of L & C element which are cross connected. The Z-source inverter consists of a unique impedance network (or circuit) to couple the inverter main circuit to the power supply, hence providing great features that cannot be observed in the conventional voltage-source inverter and current-source inverters in which capacitor and inductor are used, respectively.In the field oriented control method or vector control method speed of the induction motor, torque & 3 phase stator current is given to the field oriented controller and gate pulses for the inverter is generated to obtain the desired operation of the induction motor.
FIRING ANGLE SVC MODEL FOR ANALYZING THE PERFORMANCE OF TRANSMISSION NETWORK ...IAEME Publication
This paper deals with Power flow, which is necessary for any power system solution and carry
out a comprehensive study of the Newton- Raphson method of power flow analysis with and without
SVC. Voltage stability analysis is the major concern in order to operate any power system as
secured. This paper presents the investigation on N-R power flow enhancement of voltage stability
and power loss minimization with & without FACTS controllers such as Static Var Compensator
(SVC) device. The Static Var Compensator (SVC) provides a promising means to control power
flow in modern power systems. In this paper the Newton-Raphson is used to investigate its effect on
voltage profile and power system lossess with and without SVC in power system.. Simulations
investigate the effect of voltage magnitude and angle with and without SVC on the power flow of
the system. This survey article will be very much useful to the researchers for finding out the
relevant references in the field of Newton-Raphson power flow control with SVC in power systems.
In order to reach the above goals, these devices must be located optimally. In this paper the
Optimal placement of SVC is carried out by Voltage collapse Prediction Index (VCPI).The size of
the SVC is determined by suitable firing angle which reduces the losses in the system. Simulations
have been implemented in MATLAB Software and the IEEE 14 and IEEE 57-bus systems have been
used as case studies.
This paper presents the design and the implementation of a new microcontroller-based solar
Power inverter. The aim of this paper is to design single phase inverter which can convert DC voltage
to AC voltage at high efficiency and low cost. Solar and wind powered electricity generation are
being favored nowadays as the world increasingly focuses on environmental concerns. Power
inverters, which convert solar-cell DC into domestic-use AC, are one of the key technologies for
delivering efficient AC power The hardware and software design are oriented towards a single-chip
microcontroller-based system, hence minimizing the size and cost. With this new approach the
modularization of the conversion from solar power to electric power at its maximum power point can
be made more compact and more reliable.
Application of single phase matrix converter topology to an uninterruptible 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
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.
Analysis and Simulation of Solar PV Connected with Grid Accomplished with Boo...YogeshIJTSRD
This paper deals with a solar PV array connected with grid system. This system consists of PV cells with 30 KW system, Boost converter, three phase inverter with suitable control system and three phase load. This paper gives analysis of each components of the system. The output voltage from the solar PV cells are variable according to radiation intensity and temperature so in order to connect with grid the output voltage should be fixed and converted to AC voltage and this job will be done by an inverter. A very effective control system has been developed for the inverter based on pulse width modulation. This paper presents an intensive performance and dynamic behavior of a grid related PV energy conversion system. The PV system is developed and simulated with the help of MATLAB Simulink software environment. Abhishek Verma | Dr. Anup Mishra | Brahma Nand Thakur "Analysis and Simulation of Solar PV Connected with Grid Accomplished with Boost Converter and PWM Based Inverter" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-3 , April 2021, URL: https://www.ijtsrd.com/papers/ijtsrd40056.pdf Paper URL: https://www.ijtsrd.com/engineering/electrical-engineering/40056/analysis-and-simulation-of-solar-pv-connected-with-grid-accomplished-with-boost-converter-and-pwm-based-inverter/abhishek-verma
Performance and Analysis of Hybrid Multilevel Inverter fed Induction Motor Drivernvsubbarao koppineni
This paper presents the Five level inverter with single DC source which is used to generate a five level output with two bridges and six switches and performance of three phase induction motor is analyzed when connected to PV array For this two identical dc sources of 50V each for two bridges in five levels using Multi level inverter and five level output is obtained by using a single DC source of 100V with six switches. A virtual DC source (charged capacitor acts as virtual DC source) is used for getting the output. The same technique is implemented for three-phase circuit i.e. by using single DC source. An asynchronous motor (three-phase) is connected as load and its performance characteristics are analyzed. And further the DC source is replaced by a renewable resource such as solar panels, fuel cell etc. and DC voltage is obtained. Performance characteristics of three-phase asynchronous motor are analyzed with PV array connected. The method can be easily extended to an m-level inverter.
LOW VOLTAGE RIDE - THROUGH CAPABILITY OF WIND FARMSEditor IJMTER
Nowadays wind turbines are generally required to offer ancillary services similar to those
provided by conventional generators. One of the most important services wind turbines must offer is
to stay connected to the grid in fault situations delivering the reactive current specified in the recent
grid codes. In this paper, FACTS solutions for fixed speed wind farms such as DVR (Dynamic
Voltage Restorer) are presented as well as classic control and crowbar solutions for variable speed
wind turbines.
Improvement In Pre-Regulation For Power Factor Using CUK ConverterIJRES Journal
Cuk converters, operating in Discontinuous Capacitor Voltage Mode can achieve unity power factor when used as rectifiers with no need of duty-cycle modulation. This operating mode causes high voltage stresses across the semiconductors, calling for high-voltage switches like IGBT's. However, zero-voltage turn-off is achieved, resulting in limited power loss even at high frequency. Both current- and voltage-fed approaches as well as constant- and variable-frequency control are analyzed in the paper. Simulation and experimental results are Explained, which demonstrate actual converter performance. Most of the power factor regulator topologies in continuous conduction mode result in bulky magnetic, and in discontinuous conduction mode result in high harmonic content. To solve these problems a Cuk topology is presented in discontinuous conduction mode with coupled inductors for power factor regulation, the unique feature exhibited by the converter that makes the converter better than the other converter in operation for power factor regulation. Inductive coupling is used to transfer the ripple from the input to the output side thereby reducing the switching harmonics in the line current. Experimental results obtained on a some Watt prototype are also presented.
A brief introduction on the principles of particle swarm optimizaton by Rajorshi Mukherjee. This presentation has been compiled from various sources (not my own work) and proper references have been made in the bibliography section for further reading. This presentation was made as a presentation for submission for our college subject Soft Computing.
Nowadays power electronics circuits are embedded to most of electrical application areas. This approached offers a great control mechanism with simple and easy circuit configuration. Switched Reluctance Motor (SRM) is one of the most recent apparatus which draws a great number of researchers’ interests. Previously several attempts are made to use the power converters as driver for SRM such as Voltage Source Inverter (VSI) and bridge converters. This paper presents an analysis study of three level inverter to control the SRM. The inverter is controlled using space vector modulation SVM. The aim of this paper is to report the use the multilevel inverter to be fed into the SRM. The implementation of the multilevel inverter is abl to reduce the Total Harmonics Distortion (THD). Performance comparison are made between the multilevel and previous power electronics circuits that applied to the SRM. The simulation results have been conducted by MATLAB/SIMULINK software.
Fuzzy based control of Transformer less Coupled inductor based DC-DC converterIJERA Editor
Most of the industrial applications use any one of the basic DC-DC converter configurations namely buck,
boost, buck–boost, and Cuk converters. These converters are non-isolating converters. Buck-boost converters
use inductors for storing energy from the source and release the same to load or output. This results in high
stress across magnetic components. This drawback restricts usage of buck-boost converters to low power
applications. Flyback converters popularly have known as buck-boost converters uses transformers for
achieving wide range of step down and step up voltages. Coupled inductor based converters or tapped inductor
based converters are used for achieving wide input – wide output conversion ratios. Coherent transition between
step-down and step-up modes is achieved by a proper control scheme. This paper proposes fuzzy logic based
closed loop control scheme for control of converter switches. Theoretical derivations of control parameters with
their membership values, mamdani based rules for development of fuzzy rules and simulation results of a
coupled inductor based DC-DC converter using MATLAB / SIMULINK are concluded.
Single Phase Matrix Converter for Input Power Factor Improvementiosrjce
IOSR Journal of Electrical and Electronics Engineering(IOSR-JEEE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of electrical and electronics engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electrical and electronics engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Pi controller based of multi level upqc using dq0 transformation to improve 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.
Close Loop Control of Induction Motor Using Z-Source InverterIJSRD
In this paper a new closed loop control of induction motor fed by a Z – source inverter based on the vector control or field oriented control strategy is presented. Induction motor is supplied by Z – source inverter, in the Z – source inverter the term Z denotes impedance which means a combination of L & C element which are cross connected. The Z-source inverter consists of a unique impedance network (or circuit) to couple the inverter main circuit to the power supply, hence providing great features that cannot be observed in the conventional voltage-source inverter and current-source inverters in which capacitor and inductor are used, respectively.In the field oriented control method or vector control method speed of the induction motor, torque & 3 phase stator current is given to the field oriented controller and gate pulses for the inverter is generated to obtain the desired operation of the induction motor.
FIRING ANGLE SVC MODEL FOR ANALYZING THE PERFORMANCE OF TRANSMISSION NETWORK ...IAEME Publication
This paper deals with Power flow, which is necessary for any power system solution and carry
out a comprehensive study of the Newton- Raphson method of power flow analysis with and without
SVC. Voltage stability analysis is the major concern in order to operate any power system as
secured. This paper presents the investigation on N-R power flow enhancement of voltage stability
and power loss minimization with & without FACTS controllers such as Static Var Compensator
(SVC) device. The Static Var Compensator (SVC) provides a promising means to control power
flow in modern power systems. In this paper the Newton-Raphson is used to investigate its effect on
voltage profile and power system lossess with and without SVC in power system.. Simulations
investigate the effect of voltage magnitude and angle with and without SVC on the power flow of
the system. This survey article will be very much useful to the researchers for finding out the
relevant references in the field of Newton-Raphson power flow control with SVC in power systems.
In order to reach the above goals, these devices must be located optimally. In this paper the
Optimal placement of SVC is carried out by Voltage collapse Prediction Index (VCPI).The size of
the SVC is determined by suitable firing angle which reduces the losses in the system. Simulations
have been implemented in MATLAB Software and the IEEE 14 and IEEE 57-bus systems have been
used as case studies.
This paper presents the design and the implementation of a new microcontroller-based solar
Power inverter. The aim of this paper is to design single phase inverter which can convert DC voltage
to AC voltage at high efficiency and low cost. Solar and wind powered electricity generation are
being favored nowadays as the world increasingly focuses on environmental concerns. Power
inverters, which convert solar-cell DC into domestic-use AC, are one of the key technologies for
delivering efficient AC power The hardware and software design are oriented towards a single-chip
microcontroller-based system, hence minimizing the size and cost. With this new approach the
modularization of the conversion from solar power to electric power at its maximum power point can
be made more compact and more reliable.
Application of single phase matrix converter topology to an uninterruptible 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
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.
Analysis and Simulation of Solar PV Connected with Grid Accomplished with Boo...YogeshIJTSRD
This paper deals with a solar PV array connected with grid system. This system consists of PV cells with 30 KW system, Boost converter, three phase inverter with suitable control system and three phase load. This paper gives analysis of each components of the system. The output voltage from the solar PV cells are variable according to radiation intensity and temperature so in order to connect with grid the output voltage should be fixed and converted to AC voltage and this job will be done by an inverter. A very effective control system has been developed for the inverter based on pulse width modulation. This paper presents an intensive performance and dynamic behavior of a grid related PV energy conversion system. The PV system is developed and simulated with the help of MATLAB Simulink software environment. Abhishek Verma | Dr. Anup Mishra | Brahma Nand Thakur "Analysis and Simulation of Solar PV Connected with Grid Accomplished with Boost Converter and PWM Based Inverter" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-3 , April 2021, URL: https://www.ijtsrd.com/papers/ijtsrd40056.pdf Paper URL: https://www.ijtsrd.com/engineering/electrical-engineering/40056/analysis-and-simulation-of-solar-pv-connected-with-grid-accomplished-with-boost-converter-and-pwm-based-inverter/abhishek-verma
Performance and Analysis of Hybrid Multilevel Inverter fed Induction Motor Drivernvsubbarao koppineni
This paper presents the Five level inverter with single DC source which is used to generate a five level output with two bridges and six switches and performance of three phase induction motor is analyzed when connected to PV array For this two identical dc sources of 50V each for two bridges in five levels using Multi level inverter and five level output is obtained by using a single DC source of 100V with six switches. A virtual DC source (charged capacitor acts as virtual DC source) is used for getting the output. The same technique is implemented for three-phase circuit i.e. by using single DC source. An asynchronous motor (three-phase) is connected as load and its performance characteristics are analyzed. And further the DC source is replaced by a renewable resource such as solar panels, fuel cell etc. and DC voltage is obtained. Performance characteristics of three-phase asynchronous motor are analyzed with PV array connected. The method can be easily extended to an m-level inverter.
LOW VOLTAGE RIDE - THROUGH CAPABILITY OF WIND FARMSEditor IJMTER
Nowadays wind turbines are generally required to offer ancillary services similar to those
provided by conventional generators. One of the most important services wind turbines must offer is
to stay connected to the grid in fault situations delivering the reactive current specified in the recent
grid codes. In this paper, FACTS solutions for fixed speed wind farms such as DVR (Dynamic
Voltage Restorer) are presented as well as classic control and crowbar solutions for variable speed
wind turbines.
Improvement In Pre-Regulation For Power Factor Using CUK ConverterIJRES Journal
Cuk converters, operating in Discontinuous Capacitor Voltage Mode can achieve unity power factor when used as rectifiers with no need of duty-cycle modulation. This operating mode causes high voltage stresses across the semiconductors, calling for high-voltage switches like IGBT's. However, zero-voltage turn-off is achieved, resulting in limited power loss even at high frequency. Both current- and voltage-fed approaches as well as constant- and variable-frequency control are analyzed in the paper. Simulation and experimental results are Explained, which demonstrate actual converter performance. Most of the power factor regulator topologies in continuous conduction mode result in bulky magnetic, and in discontinuous conduction mode result in high harmonic content. To solve these problems a Cuk topology is presented in discontinuous conduction mode with coupled inductors for power factor regulation, the unique feature exhibited by the converter that makes the converter better than the other converter in operation for power factor regulation. Inductive coupling is used to transfer the ripple from the input to the output side thereby reducing the switching harmonics in the line current. Experimental results obtained on a some Watt prototype are also presented.
A brief introduction on the principles of particle swarm optimizaton by Rajorshi Mukherjee. This presentation has been compiled from various sources (not my own work) and proper references have been made in the bibliography section for further reading. This presentation was made as a presentation for submission for our college subject Soft Computing.
A Integrated Technique of SIDO PFC Fly back Converter in power systemIJMTST Journal
Energy saving is the major international efforts to control down the global warming .Power electronics based devices has being improving day by day for saving the electrical energy in the power grids. The govt. of India is also contributing several projects based on energy conservation. The Designing of a single-inductor dual output (SIDO) fly-back power factor correction (PFC) converter is proposed, in which the PFC and power conversion are done at the same time, multiplexing of a single-inductor is implemented through which each output can be regulated independently. The converter will be operating under in critical conduction mode (CRM). A SIDO PFC converter is a system of dual efficient DC output obtained from the AC source, it can also be replaced by solar panel and our system is capable of running a dc motor also, fly back converter can be used in both ac-dc and dc-dc conversion process. The efficiency along with power factor, total harmonic distortion (THD), settling time and output accuracy of this converter will be improved by implementing the neural network as controllers in the system
This paper presents the detail circuitry modeling of single phase off-grid inverter for small standalone system applications. The entire model is developed in MATLAB/Simulink platform using circuitry model. This off grid inverter consists of a high frequency DC-DC step up converter cascaded with a full bridge PI control voltage source inverter using SPWM modulation with LC filter to produce sine wave output. This is a common design used in many small commercial off-grid inverter. This off-grid inverter model is capable to produce AC sinewave output voltage at 230 V 50 Hz up to 1 kW power from a 48 V DC lead acid battery source. The AC sine wave output waveform achieved a voltage Total Harmonic Distortion (THD) of less than 1 % which is almost a pure sine wave. The conversion efficiency performance of the off-grid inverter achieved more than 94 %. The performance of the model is validated by real commercial off-grid inverter. The performance validation experiment shows that the off-grid inverter Simulink model conversion efficiency and THD performance are comparable to the commercial off-grid inverter. This model contributes to assist small to medium standalone system load and battery sizing design with greater accuracy.
Analysis of Fuel Cell Based Multilevel DC-DC Boost Converter for Induction MotorIJMTST Journal
In this paper new topologies and interleaving modulation concepts for multilevel DC-DC boost converter
enabling a significantly less loss and a reduced chip size of the power semiconductors are proposed. The
distributed generation (DG) systems based on the renewable energy sources have rapidly developed in
recent years. These DG systems are powered by micro sources such as fuel cells, photovoltaic (PV) systems,
and batteries. Fuel cells are considered to be one of the most promising sources of distributed energy because
of their high efficiency, low environmental impact and scalability. Non-isolated high step-up DC-DC
converters are required in the industrial applications. Many of these conventional DC–DC converters have the
disadvantages of operating at high duty-cycle, high switch voltage stress and high diode peak current. A
three-level step up converter is implemented to boost the fuel cell stack voltage of 96V to 340V. The proposed
converter consists a system of fuel cell based Multilevel DC-DC converter with PI controller is modeled and
simulated by using Matlab/Simulink.
A new closed loop AC to DC ĈUK converter is presented in this paper. The conventional ĈUK AC to DC converter has no feedback circuit. Thereby, the output voltage of the converter changes while changing the load. The proposed closed loop converter can regulate voltage with the variation of load over a wide range. Moreover, the power factor and Total Harmonic Distortion (THD) of the supply side current found quite satisfactory from this closed loop ĈUK converter. The converter operates in four steps with a different combination of voltage polarities and switching states. The feedback path consists of a voltage control loop and a current control loop. The closed loop ĈUK converter in this study is compared with the open loop version. Additionally, the comparison is made with the conventional converter of the same topology. The effectiveness in terms of power factor and THD of the proposed converter is verified using simulation results.
A Novel High Gain SEPIC Converter with the Tapped Inductor Model Operating in...IJPEDS-IAES
Power factor correction (PFC) has become one of the most active research
areas in the field of power electronics due to the surplus power required for
various industrial applications around the world. In this work, a novel SEPIC
converter with the tapped inductor model operating in discontinuous
conduction mode (TI-SEPIC- DCM) is proposed for PFC. The proposed TISEPIC-
DCM improves the voltage gain through voltage multiplier cell and
charge pump circuit. The voltage multiplier cell also helps in attaining the
zero-voltage switching (ZVS) and zero-current switching (ZCS), which
results in higher switching frequency and size reduction. Moreover, a third
order harmonic reduction control loop has been proposed for better harmonic
mitigation. The proposed work has been simulated in MATLAB and the
results are obtained to validate the significance of the proposed TI-SEPICDCM
with near unity power factor and reduced harmonics.
A non-isolated tri-port converter is a fully compact and functional system by the integration of basic converters. This can be used for renewable energy applications. This converter is capable of achieving different switching patterns of power flow between the source and load, interfaced sources of various voltage and current levels with the dc grid. This tri-port converter has to be used for continuous power distribution of rechargeable battery, photovoltaic panels and load. Due to the implementation of this dc-dc converter some operations like buck, boost and buck-boost operations became easy. Use of this converter helps in easy implementation of the system. The solar PV panel implementation boosts the system to a high level and bidirectional flow became easy from source to load and vice versa.
This paper presents parameters analysis of 4-level capacitor-clamped boost converter with hard-switching and soft-switching implementation. Principally, by considering the selected circuit structure of the 4-level capacitor-clamped boost converter and appropriate pulse width modulation (PWM) switching strategy, the overall converter volume able to be reduced. Specifically, phase-shifted of 120° of each switching signal is applied in the 4-level capacitor-clamped boost converter in order to increase the inductor current ripple frequency, thus the charging and discharging times of the inductor is reduced. Besides, volume of converters is greatly reduced if very high switching frequency is considered. However, it causes increasing of semiconductor losses and consequently the converter efficiency is affected. The results show that the efficiency of 2-level conventional boost converter and 4-level capacitor-clamped boost converter are 98.59% and 97.67%, respectively in hard-switching technique, and 99.31% and 98.15%, respectively in soft-switching technique. Therefore, by applying soft-switching technique, switching loss of the semiconductor devices is greatly minimized although high switching frequency is applied. In this study, passive lossless snubber circuit is selected for the soft-switching implementation in the 4-level capacitor-clamped boost converter. Based on the simulation results, the switching loss is approximately eliminated by applying soft-switching technique compared to the hard-switching technique implementation.
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.
Cascaded H-BRIDGE Converter for Domestic ApplicationsIJTET Journal
Multilevel inverters have recently found its way in to the high power applications in both domestic and industrial fields with its ability of low switching frequency. Out of all the topologies of a multilevel inverter, the cascaded H-bridge inverter is most commonly used due to its modular topology. This paper presents a five level cascaded multilevel inverter whose dc voltage source is charged by a solar panel. The switching is done by PIC microcontroller. The programming of the microcontroller is done using MPLAB programmer. Topology is designed with minimum size, weight & reduced power losses. The simulation work is done using MATLAB and experimental results have been presented to validate the theory.
Renewable Energy Based on Current Fed Switched Inverter for Smart Grid Applic...MangaiK4
Abstract - Renewable energy is used in the current fed switched inverter for high power production. High voltage support, wide yield ranges of operation, shoot-through resistance are a portion of the desired properties of an inverter for a reliable, versatile and less ripple AC inversion. This paper proposes a single stage, high boost inverter with buck-boost capacity which has a few particular advantages over traditional voltage source inverters (VSI) like better EMI noise, wide input and output voltage range of operation, and so on. The proposed inverter is named as Current-Fed Switched Inverter (CFSI). A renewable energy based converter structure of CFSI has been created which supplies both AC and DC loads, at the same time, from a single DC supply which makes it reasonable for DC smart grid application. This paper proposes the operation and control of a CFSI based converter which directs the AC and DC conversion voltages at their reference. The advancement of the proposed converter from essential current fed DC/DC topology is explained. The closed loop controller is verified by using the MATLAB/ Simulink environment.
High gain dc-dc step up converters have been used in renewable energy systems, for example, photovoltaic grid connected system and fuel cell power plant to step up the low level dc voltage to a high level dc bus voltage. If the conventional boost converter is to meet this demand, it should be operated at an extreme duty cycle (duty cycle closes to unity), which will cause electromagnetic interference, reverse recovery problem and conduction loss at the power switches. This paper proposes a class of non-isolated dc-dc step up converters which provide very high voltage gain at a small duty cycle (duty cycle < 0.5). Firstly, the converter topologies are derived based on active switched inductor network and combination of active and passive switched inductor networks; secondly, the modes of operation of proposed active switched inductor converter and combined active and passive switched inductor converter are illustrated; thirdly, the performance of the proposed converters are analyzed mathematically in details and compared with conventional boost converter. Finally, the analysis is verified by simulation results.
Similar to DESIGN OF A MULTIFUNCTIONAL FLYBACK DC-DC CONVERTER WITH CURRENT CONTROL (20)
Submission Deadline: 30th September 2022
Acceptance Notification: Within Three Days’ time period
Online Publication: Within 24 Hrs. time Period
Expected Date of Dispatch of Printed Journal: 5th October 2022
MODELING AND ANALYSIS OF SURFACE ROUGHNESS AND WHITE LATER THICKNESS IN WIRE-...IAEME Publication
White layer thickness (WLT) formed and surface roughness in wire electric discharge turning (WEDT) of tungsten carbide composite has been made to model through response surface methodology (RSM). A Taguchi’s standard Design of experiments involving five input variables with three levels has been employed to establish a mathematical model between input parameters and responses. Percentage of cobalt content, spindle speed, Pulse on-time, wire feed and pulse off-time were changed during the experimental tests based on the Taguchi’s orthogonal array L27 (3^13). Analysis of variance (ANOVA) revealed that the mathematical models obtained can adequately describe performance within the parameters of the factors considered. There was a good agreement between the experimental and predicted values in this study.
A STUDY ON THE REASONS FOR TRANSGENDER TO BECOME ENTREPRENEURSIAEME Publication
The study explores the reasons for a transgender to become entrepreneurs. In this study transgender entrepreneur was taken as independent variable and reasons to become as dependent variable. Data were collected through a structured questionnaire containing a five point Likert Scale. The study examined the data of 30 transgender entrepreneurs in Salem Municipal Corporation of Tamil Nadu State, India. Simple Random sampling technique was used. Garrett Ranking Technique (Percentile Position, Mean Scores) was used as the analysis for the present study to identify the top 13 stimulus factors for establishment of trans entrepreneurial venture. Economic advancement of a nation is governed upon the upshot of a resolute entrepreneurial doings. The conception of entrepreneurship has stretched and materialized to the socially deflated uncharted sections of transgender community. Presently transgenders have smashed their stereotypes and are making recent headlines of achievements in various fields of our Indian society. The trans-community is gradually being observed in a new light and has been trying to achieve prospective growth in entrepreneurship. The findings of the research revealed that the optimistic changes are taking place to change affirmative societal outlook of the transgender for entrepreneurial ventureship. It also laid emphasis on other transgenders to renovate their traditional living. The paper also highlights that legislators, supervisory body should endorse an impartial canons and reforms in Tamil Nadu Transgender Welfare Board Association.
BROAD UNEXPOSED SKILLS OF TRANSGENDER ENTREPRENEURSIAEME Publication
Since ages gender difference is always a debatable theme whether caused by nature, evolution or environment. The birth of a transgender is dreadful not only for the child but also for their parents. The pain of living in the wrong physique and treated as second class victimized citizen is outrageous and fully harboured with vicious baseless negative scruples. For so long, social exclusion had perpetuated inequality and deprivation experiencing ingrained malign stigma and besieged victims of crime or violence across their life spans. They are pushed into the murky way of life with a source of eternal disgust, bereft sexual potency and perennial fear. Although they are highly visible but very little is known about them. The common public needs to comprehend the ravaged arrogance on these insensitive souls and assist in integrating them into the mainstream by offering equal opportunity, treat with humanity and respect their dignity. Entrepreneurship in the current age is endorsing the gender fairness movement. Unstable careers and economic inadequacy had inclined one of the gender variant people called Transgender to become entrepreneurs. These tiny budding entrepreneurs resulted in economic transition by means of employment, free from the clutches of stereotype jobs, raised standard of living and handful of financial empowerment. Besides all these inhibitions, they were able to witness a platform for skill set development that ignited them to enter into entrepreneurial domain. This paper epitomizes skill sets involved in trans-entrepreneurs of Thoothukudi Municipal Corporation of Tamil Nadu State and is a groundbreaking determination to sightsee various skills incorporated and the impact on entrepreneurship.
DETERMINANTS AFFECTING THE USER'S INTENTION TO USE MOBILE BANKING APPLICATIONSIAEME Publication
The banking and financial services industries are experiencing increased technology penetration. Among them, the banking industry has made technological advancements to better serve the general populace. The economy focused on transforming the banking sector's system into a cashless, paperless, and faceless one. The researcher wants to evaluate the user's intention for utilising a mobile banking application. The study also examines the variables affecting the user's behaviour intention when selecting specific applications for financial transactions. The researcher employed a well-structured questionnaire and a descriptive study methodology to gather the respondents' primary data utilising the snowball sampling technique. The study includes variables like performance expectations, effort expectations, social impact, enabling circumstances, and perceived risk. Each of the aforementioned variables has a major impact on how users utilise mobile banking applications. The outcome will assist the service provider in comprehending the user's history with mobile banking applications.
ANALYSE THE USER PREDILECTION ON GPAY AND PHONEPE FOR DIGITAL TRANSACTIONSIAEME Publication
Technology upgradation in banking sector took the economy to view that payment mode towards online transactions using mobile applications. This system enabled connectivity between banks, Merchant and user in a convenient mode. there are various applications used for online transactions such as Google pay, Paytm, freecharge, mobikiwi, oxygen, phonepe and so on and it also includes mobile banking applications. The study aimed at evaluating the predilection of the user in adopting digital transaction. The study is descriptive in nature. The researcher used random sample techniques to collect the data. The findings reveal that mobile applications differ with the quality of service rendered by Gpay and Phonepe. The researcher suggest the Phonepe application should focus on implementing the application should be user friendly interface and Gpay on motivating the users to feel the importance of request for money and modes of payments in the application.
VOICE BASED ATM FOR VISUALLY IMPAIRED USING ARDUINOIAEME Publication
The prototype of a voice-based ATM for visually impaired using Arduino is to help people who are blind. This uses RFID cards which contain users fingerprint encrypted on it and interacts with the users through voice commands. ATM operates when sensor detects the presence of one person in the cabin. After scanning the RFID card, it will ask to select the mode like –normal or blind. User can select the respective mode through voice input, if blind mode is selected the balance check or cash withdraw can be done through voice input. Normal mode procedure is same as the existing ATM.
IMPACT OF EMOTIONAL INTELLIGENCE ON HUMAN RESOURCE MANAGEMENT PRACTICES AMONG...IAEME Publication
There is increasing acceptability of emotional intelligence as a major factor in personality assessment and effective human resource management. Emotional intelligence as the ability to build capacity, empathize, co-operate, motivate and develop others cannot be divorced from both effective performance and human resource management systems. The human person is crucial in defining organizational leadership and fortunes in terms of challenges and opportunities and walking across both multinational and bilateral relationships. The growing complexity of the business world requires a great deal of self-confidence, integrity, communication, conflict and diversity management to keep the global enterprise within the paths of productivity and sustainability. Using the exploratory research design and 255 participants the result of this original study indicates strong positive correlation between emotional intelligence and effective human resource management. The paper offers suggestions on further studies between emotional intelligence and human capital development and recommends for conflict management as an integral part of effective human resource management.
VISUALISING AGING PARENTS & THEIR CLOSE CARERS LIFE JOURNEY IN AGING ECONOMYIAEME Publication
Our life journey, in general, is closely defined by the way we understand the meaning of why we coexist and deal with its challenges. As we develop the "inspiration economy", we could say that nearly all of the challenges we have faced are opportunities that help us to discover the rest of our journey. In this note paper, we explore how being faced with the opportunity of being a close carer for an aging parent with dementia brought intangible discoveries that changed our insight of the meaning of the rest of our life journey.
A STUDY ON THE IMPACT OF ORGANIZATIONAL CULTURE ON THE EFFECTIVENESS OF PERFO...IAEME Publication
The main objective of this study is to analyze the impact of aspects of Organizational Culture on the Effectiveness of the Performance Management System (PMS) in the Health Care Organization at Thanjavur. Organizational Culture and PMS play a crucial role in present-day organizations in achieving their objectives. PMS needs employees’ cooperation to achieve its intended objectives. Employees' cooperation depends upon the organization’s culture. The present study uses exploratory research to examine the relationship between the Organization's culture and the Effectiveness of the Performance Management System. The study uses a Structured Questionnaire to collect the primary data. For this study, Thirty-six non-clinical employees were selected from twelve randomly selected Health Care organizations at Thanjavur. Thirty-two fully completed questionnaires were received.
Living in 21st century in itself reminds all of us the necessity of police and its administration. As more and more we are entering into the modern society and culture, the more we require the services of the so called ‘Khaki Worthy’ men i.e., the police personnel. Whether we talk of Indian police or the other nation’s police, they all have the same recognition as they have in India. But as already mentioned, their services and requirements are different after the like 26th November, 2008 incidents, where they without saving their own lives has sacrificed themselves without any hitch and without caring about their respective family members and wards. In other words, they are like our heroes and mentors who can guide us from the darkness of fear, militancy, corruption and other dark sides of life and so on. Now the question arises, if Gandhi would have been alive today, what would have been his reaction/opinion to the police and its functioning? Would he have some thing different in his mind now what he had been in his mind before the partition or would he be going to start some Satyagraha in the form of some improvement in the functioning of the police administration? Really these questions or rather night mares can come to any one’s mind, when there is too much confusion is prevailing in our minds, when there is too much corruption in the society and when the polices working is also in the questioning because of one or the other case throughout the India. It is matter of great concern that we have to thing over our administration and our practical approach because the police personals are also like us, they are part and parcel of our society and among one of us, so why we all are pin pointing towards them.
A STUDY ON TALENT MANAGEMENT AND ITS IMPACT ON EMPLOYEE RETENTION IN SELECTED...IAEME Publication
The goal of this study was to see how talent management affected employee retention in the selected IT organizations in Chennai. The fundamental issue was the difficulty to attract, hire, and retain talented personnel who perform well and the gap between supply and demand of talent acquisition and retaining them within the firms. The study's main goals were to determine the impact of talent management on employee retention in IT companies in Chennai, investigate talent management strategies that IT companies could use to improve talent acquisition, performance management, career planning and formulate retention strategies that the IT firms could use. The respondents were given a structured close-ended questionnaire with the 5 Point Likert Scale as part of the study's quantitative research design. The target population consisted of 289 IT professionals. The questionnaires were distributed and collected by the researcher directly. The Statistical Package for Social Sciences (SPSS) was used to collect and analyse the questionnaire responses. Hypotheses that were formulated for the various areas of the study were tested using a variety of statistical tests. The key findings of the study suggested that talent management had an impact on employee retention. The studies also found that there is a clear link between the implementation of talent management and retention measures. Management should provide enough training and development for employees, clarify job responsibilities, provide adequate remuneration packages, and recognise employees for exceptional performance.
ATTRITION IN THE IT INDUSTRY DURING COVID-19 PANDEMIC: LINKING EMOTIONAL INTE...IAEME Publication
Globally, Millions of dollars were spent by the organizations for employing skilled Information Technology (IT) professionals. It is costly to replace unskilled employees with IT professionals possessing technical skills and competencies that aid in interconnecting the business processes. The organization’s employment tactics were forced to alter by globalization along with technological innovations as they consistently diminish to remain lean, outsource to concentrate on core competencies along with restructuring/reallocate personnel to gather efficiency. As other jobs, organizations or professions have become reasonably more appropriate in a shifting employment landscape, the above alterations trigger both involuntary as well as voluntary turnover. The employee view on jobs is also afflicted by the COVID-19 pandemic along with the employee-driven labour market. So, having effective strategies is necessary to tackle the withdrawal rate of employees. By associating Emotional Intelligence (EI) along with Talent Management (TM) in the IT industry, the rise in attrition rate was analyzed in this study. Only 303 respondents were collected out of 350 participants to whom questionnaires were distributed. From the employees of IT organizations located in Bangalore (India), the data were congregated. A simple random sampling methodology was employed to congregate data as of the respondents. Generating the hypothesis along with testing is eventuated. The effect of EI and TM along with regression analysis between TM and EI was analyzed. The outcomes indicated that employee and Organizational Performance (OP) were elevated by effective EI along with TM.
INFLUENCE OF TALENT MANAGEMENT PRACTICES ON ORGANIZATIONAL PERFORMANCE A STUD...IAEME Publication
By implementing talent management strategy, organizations would have the option to retain their skilled professionals while additionally working on their overall performance. It is the course of appropriately utilizing the ideal individuals, setting them up for future top positions, exploring and dealing with their performance, and holding them back from leaving the organization. It is employee performance that determines the success of every organization. The firm quickly obtains an upper hand over its rivals in the event that its employees having particular skills that cannot be duplicated by the competitors. Thus, firms are centred on creating successful talent management practices and processes to deal with the unique human resources. Firms are additionally endeavouring to keep their top/key staff since on the off chance that they leave; the whole store of information leaves the firm's hands. The study's objective was to determine the impact of talent management on organizational performance among the selected IT organizations in Chennai. The study recommends that talent management limitedly affects performance. On the off chance that this talent is appropriately management and implemented properly, organizations might benefit as much as possible from their maintained assets to support development and productivity, both monetarily and non-monetarily.
A STUDY OF VARIOUS TYPES OF LOANS OF SELECTED PUBLIC AND PRIVATE SECTOR BANKS...IAEME Publication
Banking regulations act of India, 1949 defines banking as “acceptance of deposits for the purpose of lending or investment from the public, repayment on demand or otherwise and withdrawable through cheques, drafts order or otherwise”, the major participants of the Indian financial system are commercial banks, the financial institution encompassing term lending institutions. Investments institutions, specialized financial institution and the state level development banks, non banking financial companies (NBFC) and other market intermediaries such has the stock brokers and money lenders are among the oldest of the certain variants of NBFC and the oldest market participants. The asset quality of banks is one of the most important indicators of their financial health. The Indian banking sector has been facing severe problems of increasing Non- Performing Assets (NPAs). The NPAs growth directly and indirectly affects the quality of assets and profitability of banks. It also shows the efficiency of banks credit risk management and the recovery effectiveness. NPA do not generate any income, whereas, the bank is required to make provisions for such as assets that why is a double edge weapon. This paper outlines the concept of quality of bank loans of different types like Housing, Agriculture and MSME loans in state Haryana of selected public and private sector banks. This study is highlighting problems associated with the role of commercial bank in financing Small and Medium Scale Enterprises (SME). The overall objective of the research was to assess the effect of the financing provisions existing for the setting up and operations of MSMEs in the country and to generate recommendations for more robust financing mechanisms for successful operation of the MSMEs, in turn understanding the impact of MSME loans on financial institutions due to NPA. There are many research conducted on the topic of Non- Performing Assets (NPA) Management, concerning particular bank, comparative study of public and private banks etc. In this paper the researcher is considering the aggregate data of selected public sector and private sector banks and attempts to compare the NPA of Housing, Agriculture and MSME loans in state Haryana of public and private sector banks. The tools used in the study are average and Anova test and variance. The findings reveal that NPA is common problem for both public and private sector banks and is associated with all types of loans either that is housing loans, agriculture loans and loans to SMES. NPAs of both public and private sector banks show the increasing trend. In 2010-11 GNPA of public and private sector were at same level it was 2% but after 2010-11 it increased in many fold and at present there is GNPA in some more than 15%. It shows the dark area of Indian banking sector.
EXPERIMENTAL STUDY OF MECHANICAL AND TRIBOLOGICAL RELATION OF NYLON/BaSO4 POL...IAEME Publication
An experiment conducted in this study found that BaSO4 changed Nylon 6's mechanical properties. By changing the weight ratios, BaSO4 was used to make Nylon 6. This Researcher looked into how hard Nylon-6/BaSO4 composites are and how well they wear. Experiments were done based on Taguchi design L9. Nylon-6/BaSO4 composites can be tested for their hardness number using a Rockwell hardness testing apparatus. On Nylon/BaSO4, the wear behavior was measured by a wear monitor, pinon-disc friction by varying reinforcement, sliding speed, and sliding distance, and the microstructure of the crack surfaces was observed by SEM. This study provides significant contributions to ultimate strength by increasing BaSO4 content up to 16% in the composites, and sliding speed contributes 72.45% to the wear rate
ROLE OF SOCIAL ENTREPRENEURSHIP IN RURAL DEVELOPMENT OF INDIA - PROBLEMS AND ...IAEME Publication
The majority of the population in India lives in villages. The village is the back bone of the country. Village or rural industries play an important role in the national economy, particularly in the rural development. Developing the rural economy is one of the key indicators towards a country’s success. Whether it be the need to look after the welfare of the farmers or invest in rural infrastructure, Governments have to ensure that rural development isn’t compromised. The economic development of our country largely depends on the progress of rural areas and the standard of living of rural masses. Village or rural industries play an important role in the national economy, particularly in the rural development. Rural entrepreneurship is based on stimulating local entrepreneurial talent and the subsequent growth of indigenous enterprises. It recognizes opportunity in the rural areas and accelerates a unique blend of resources either inside or outside of agriculture. Rural entrepreneurship brings an economic value to the rural sector by creating new methods of production, new markets, new products and generate employment opportunities thereby ensuring continuous rural development. Social Entrepreneurship has the direct and primary objective of serving the society along with the earning profits. So, social entrepreneurship is different from the economic entrepreneurship as its basic objective is not to earn profits but for providing innovative solutions to meet the society needs which are not taken care by majority of the entrepreneurs as they are in the business for profit making as a sole objective. So, the Social Entrepreneurs have the huge growth potential particularly in the developing countries like India where we have huge societal disparities in terms of the financial positions of the population. Still 22 percent of the Indian population is below the poverty line and also there is disparity among the rural & urban population in terms of families living under BPL. 25.7 percent of the rural population & 13.7 percent of the urban population is under BPL which clearly shows the disparity of the poor people in the rural and urban areas. The need to develop social entrepreneurship in agriculture is dictated by a large number of social problems. Such problems include low living standards, unemployment, and social tension. The reasons that led to the emergence of the practice of social entrepreneurship are the above factors. The research problem lays upon disclosing the importance of role of social entrepreneurship in rural development of India. The paper the tendencies of social entrepreneurship in India, to present successful examples of such business for providing recommendations how to improve situation in rural areas in terms of social entrepreneurship development. Indian government has made some steps towards development of social enterprises, social entrepreneurship, and social in- novation, but a lot remains to be improved.
OPTIMAL RECONFIGURATION OF POWER DISTRIBUTION RADIAL NETWORK USING HYBRID MET...IAEME Publication
Distribution system is a critical link between the electric power distributor and the consumers. Most of the distribution networks commonly used by the electric utility is the radial distribution network. However in this type of network, it has technical issues such as enormous power losses which affect the quality of the supply. Nowadays, the introduction of Distributed Generation (DG) units in the system help improve and support the voltage profile of the network as well as the performance of the system components through power loss mitigation. In this study network reconfiguration was done using two meta-heuristic algorithms Particle Swarm Optimization and Gravitational Search Algorithm (PSO-GSA) to enhance power quality and voltage profile in the system when simultaneously applied with the DG units. Backward/Forward Sweep Method was used in the load flow analysis and simulated using the MATLAB program. Five cases were considered in the Reconfiguration based on the contribution of DG units. The proposed method was tested using IEEE 33 bus system. Based on the results, there was a voltage profile improvement in the system from 0.9038 p.u. to 0.9594 p.u.. The integration of DG in the network also reduced power losses from 210.98 kW to 69.3963 kW. Simulated results are drawn to show the performance of each case.
APPLICATION OF FRUGAL APPROACH FOR PRODUCTIVITY IMPROVEMENT - A CASE STUDY OF...IAEME Publication
Manufacturing industries have witnessed an outburst in productivity. For productivity improvement manufacturing industries are taking various initiatives by using lean tools and techniques. However, in different manufacturing industries, frugal approach is applied in product design and services as a tool for improvement. Frugal approach contributed to prove less is more and seems indirectly contributing to improve productivity. Hence, there is need to understand status of frugal approach application in manufacturing industries. All manufacturing industries are trying hard and putting continuous efforts for competitive existence. For productivity improvements, manufacturing industries are coming up with different effective and efficient solutions in manufacturing processes and operations. To overcome current challenges, manufacturing industries have started using frugal approach in product design and services. For this study, methodology adopted with both primary and secondary sources of data. For primary source interview and observation technique is used and for secondary source review has done based on available literatures in website, printed magazines, manual etc. An attempt has made for understanding application of frugal approach with the study of manufacturing industry project. Manufacturing industry selected for this project study is Mahindra and Mahindra Ltd. This paper will help researcher to find the connections between the two concepts productivity improvement and frugal approach. This paper will help to understand significance of frugal approach for productivity improvement in manufacturing industry. This will also help to understand current scenario of frugal approach in manufacturing industry. In manufacturing industries various process are involved to deliver the final product. In the process of converting input in to output through manufacturing process productivity plays very critical role. Hence this study will help to evolve status of frugal approach in productivity improvement programme. The notion of frugal can be viewed as an approach towards productivity improvement in manufacturing industries.
A MULTIPLE – CHANNEL QUEUING MODELS ON FUZZY ENVIRONMENTIAEME Publication
In this paper, we investigated a queuing model of fuzzy environment-based a multiple channel queuing model (M/M/C) ( /FCFS) and study its performance under realistic conditions. It applies a nonagonal fuzzy number to analyse the relevant performance of a multiple channel queuing model (M/M/C) ( /FCFS). Based on the sub interval average ranking method for nonagonal fuzzy number, we convert fuzzy number to crisp one. Numerical results reveal that the efficiency of this method. Intuitively, the fuzzy environment adapts well to a multiple channel queuing models (M/M/C) ( /FCFS) are very well.
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.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
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.
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.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
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2. Fernando Santos, Humberto Jorge and Sérgio Cruz
http://www.iaeme.com/IJEET/index.asp 58 editor@iaeme.com
Cite this Article: Fernando Santos, Humberto Jorge and Sérgio Cruz, Design
of A Multifunctional Flyback Dc–Dc Converter with Current Control.
International Journal of Electrical Engineering & Technology, 7(3), 2016, pp.
57–72.
http://www.iaeme.com/ijeet/issues.asp?JType=IJEET&VType=7&IType=3
1. INTRODUCTION
The two main methods to reduce consumer energy costs in a house are improving
energy efficiency and increasing the use of renewable energy sources. In the last case,
there is a problem related to the fact that most of the energy produced by these
sources do not match the home energy consumption. The solution to this problem may
reside in the use of energy storage devices in order to adjust the energy generation to
the consumption demand.
On the other hand, to promote efficiency in distribution networks, it is convenient
to locate the energy storage devices closer to the consumer loads, thus reducing losses
in the distribution of electricity as well as increasing the voltage stability [1].
Another positive aspect of locating the energy storage near the loads is to give
consumers the ability to be energy suppliers as well, making them an active element
of the investment needed to shift from a carbon-based to a renewable energy-based
economy. In this context, there is a need to develop energy storage modules for low
voltage end-users. These modules can then be integrated and linked with generation
modules of different technologies and different manufacturers [2].
The work reported in this paper is part of a broader work, whose main goal is to
develop a multifunctional DC/AC power supply system for a home with renewable
energy generation, in the context of a liberalized energy market. Fig. 1 shows the
power system built with the multifunctional DC/AC system. The different renewable
energy sources, as well as the energy storage devices - batteries and supercapacitors -
are interconnected through different DC-DC converters. The DC bus supplies a DC
load and is interconnected to the grid through an inverter and an autotransformer for
adapting the voltage level. This allows the bidirectional exchange of energy between
the DC bus and the AC network. The inverter is responsible for the regulation of the
voltage in the 24 V DC bus. This voltage value was selected because it eases the
association of storage and production devices and is sufficient to supply the load
without leading to excessive current values.
3. Design of A Multifunctional Flyback Dc–Dc Converter with Current Control
http://www.iaeme.com/IJEET/index.asp 59 editor@iaeme.com
AC load
AC network (230V/400V, 50 Hz)
Inverter
SEMIKRON
132GD120-3DUL
DC load
DC-DC
converter
Batteries
Supercapacitors
Renewable
source I 24V
27V
Ib1
Ib2
ISC1
ISC2
IE
IPV1
ICDC
24V
ICAC
Autotransformer
Renewable
source II
DC-DC
converter
DC-DC
converter
DC-DC
converter
DC-DC
converter
DC-DC
converter
Figure 1 Developed multifunctional DC/AC power supply system.
A dispatch algorithm, in conjunction with the controlled DC-DC converters,
regulates the current value that each storage element or renewable source supplies to
the DC bus.
2. COMMON DC-DC CONVERTER TOPOLOGIES
Different topologies can be used in DC-DC converters, which generally are grouped
into two main categories: non-isolated and isolated converters.
Table I shows a comparison of the most common types of DC-DC converters [3-
6].
TABLE I Common Types of DC-DC Converters
Topology Isolated Cost Magnetic Components
Universal
input?
Vout < Vin
range
Vout > Vin
range
Buck No 1 Inductor No Yes No
Boost No 1 Inductor No No Yes
Buck –Boost No 1 Inductor No Yes Yes
Sepic No 1.2 Two Inductors No Yes Yes
Cuk No 1.2 Two Inductors No Yes Yes
Flyback Yes 1.5 Transformer Yes Yes Yes
Forward Yes 1.8 Transformer and Inductor Yes Yes Yes
Push-Pull Yes 1.8 Transformer and Inductor No Yes Yes
Half Bridge Yes 2 Transformer and Inductor Yes Yes Yes
Resonant LLC Yes 2 Transformer Yes Yes Yes
Among the configurations mentioned in Table I, the flyback and the resonant LLC
converters are the isolated converters with the smallest number of magnetic
components [3]. In addition, the flyback converter is the one that presents less
electronic components [7].
4. Fernando Santos, Humberto Jorge and Sérgio Cruz
http://www.iaeme.com/IJEET/index.asp 60 editor@iaeme.com
Flyback converters have been an attractive solution in various power conversion
applications due to their topological advantages such as simple structure, low cost,
and galvanic isolation between the input and output sides [8, 9].
Given these advantages, the flyback converter was the adopted topology for all
DC-DC converters shown in Fig. 1.
3. OPERATING PRINCIPLE OF FLYBACK CONVERTERS
A. Topology
Fig. 2 shows the topology of a flyback converter [10]. Initially, the power switch is
closed to allow the circulation of current in the primary circuit of the transformer,
being the energy stored in its magnetic circuit. Next, the power switch is opened and
the energy stored in the core is transferred to the secondary circuit of the transformer,
feeding the load [11].
VOUT Load
VIN
+
-
+
IIN IOUT
T1
Driver
circuit
C1
-
D1
MOS1
Figure 2 Topology of a flyback converter
B. Operation mode
There are two distinct operation modes for flyback converters: the continuous mode
and the discontinuous mode [10], [12]. Fig. 3 shows the typical waveforms for these
two operation modes.
The discontinuous mode happens when all energy stored in the transformer during
an energy storage period (“on” period) is transferred to the output during the flyback
period (“off” period) while in a continuous mode, part of the energy stored in the
transformer during the “on” period remains in the transformer at the beginning of the
next switching period [5], [12], [13].
Figure 3 Current waveforms for the two operation modes of a flyback converter.
As can be seen in Fig. 3, in the continuous mode the current in the primary side of
the transformer has a higher initial value. This higher current leads to higher
switching losses in the converter, and requires s transformer with a higher inductance,
thus increasing its size and cost [14], [15].
5. Design of A Multifunctional Flyback Dc–Dc Converter with Current Control
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Hence, the DC-DC converter designed in this paper is to be operated in a
discontinuous mode, in order to have lower losses in transformer and a higher
converter efficiency, but still being able to maintain a high voltage level at the output
side.
4. PROPOSED CONVERTER
A. Design
The Flyback transformer used in the converter is the ETD49 type for high
frequencies, with four windings in the primary side and six windings in secondary
side.
The power switch adopted for the converter is the MOSFET IRFB4332PBF
because it has a high repetitive avalanche voltage (300 V), a low static drain-to-source
on-resistance (29 mΩ at 10 V), a high repetitive peak current capability for reliable
operation and short fall and rise times for fast switching.
T1
DC
18 to 75V
C2
C3
Load
Control
system
M1
Auxiliar
power
supply
C1
D1
MOS1
D2
R1
R2
Figure 4 DC-DC flyback converter
The gate-emitter voltage applied to the MOSFET is produced by pulse width
modulation (PWM) from the output of the integrated circuit (IC) 555 CN. As the
output of this IC cannot be connected directly to the MOSFET gate, an interface
between the control signal and the power module is used, consisting in a bipolar
transistor 2N2222A (Fig. 5).
1N4148
1N4148
8.06 k
25
1 k
2N2222A
IRFB4332PBF
4.7 nF
PWM
OUT IC 555 CN
1.4 k
VCC1
GND1
Figure 5 Interface between the control signal and the power MOSFET.
The diode 1N4148 connected between the emitter of the transistor and the PWM
control signal allows to impose a zero voltage level to the MOSFET gate, thus
blocking the MOSFET whenever the PWM signal goes low. When the PWM signal
goes high, the other 1N4148 diode polarizes the base of the transistor, putting it in a
conducting state, appearing in this way a high voltage signal at the emitter terminal.
6. Fernando Santos, Humberto Jorge and Sérgio Cruz
http://www.iaeme.com/IJEET/index.asp 62 editor@iaeme.com
This high voltage level will also appear at the gate of the MOSFET, putting it in a
conducting state.
The 25 Ω resistor, connected between the emitter of the transistor and the gate of
the MOSFET, mitigates the fluctuations due to the parasitic capacitance of the
MOSFET gate, facilitating the switching operation. The 4.7 nF capacitor connected
between the gate and the source of the MOSFET ensures the stabilization of the gate
voltage.
B. Pulse width modulation
For the production of the pulse width modulated control signal, two oscillators 555
are used, as shown in Fig. 6. The first, of P-type, can operate up to a maximum
frequency of 500 kHz, and is configured as a stable oscillator. It will oscillate without
any external trigger, in order to produce an intermediate PWM signal, with an
adjustable duty-cycle with the aid of the 2.2 kΩ potentiometer.
To maintain a constant switching frequency, a special assembly was made, where
the output of the PWM intermediate PWM signal is taken from the discharge pin of
the IC 555P instead from its output pin. When the circuit in Fig. 6 is turned on, the
trigger pin of the IC 555P is in a low voltage state, as the capacitor of 3.3 nF is
discharged. This begins the oscillator cycle, causing the output pin to go into a high
state.
2.2 kΩ
680 kΩ
510 kΩ
10 kΩ
P
CS Signal
D1N5818 D1N5818
3.3 nF
0.1 µF 10 nF
VCC1
GND1
555GND VCC
TRI DIS
OUT THR
RES CON
P P
555GND VCC
TRI DIS
OUT THR
RES CON
CN
Figure 6 Generation of the PWM control signal
As soon as the output goes high, the capacitor of 3.3 nF begins to charge through
the left side of potentiometer 2.2 kΩ and the left diode D1N5818.
When the voltage at the capacitor of 3.3 nF reaches 2/3 of 12 V (VCC1=12 V), the
threshold pin is active, which in turn causes the output and discharge pins to go to a
low voltage level. In the next step, the capacitor of 3.3 nF starts to discharge through
the right side of potentiometer 2.2 kΩ and the right diode D1N5818. When the
voltage at the capacitor of 3.3 nF drops below 1/3 of 12 V, the output and discharge
pins go to a high voltage level and the cycle repeats.
The value of the charge and discharge resistor, set by the position of the
potentiometer, influences the duty cycle of the intermediate PWM signal, but the
period of this signal is always constant, as it is determined by the sum of the two
resistors, which in Fig. 6 corresponds to the value of the potentiometer resistance.
Thus, in the proposed circuit, the PWM frequency is maintained constant, whatever
the duty cycle requested. The theoretical frequency of this intermediate PWM signal
is given by [16]:
7. Design of A Multifunctional Flyback Dc–Dc Converter with Current Control
http://www.iaeme.com/IJEET/index.asp 63 editor@iaeme.com
Frequency = 1.44/ (Output resistance*Capacity in the trigger and threshold pin).
The discharge pin of IC 555P is connected to a resistor of 10 kΩ, and provides the
intermediate PWM signal to drive the second oscillator, being connected to its trigger
and reset pins.
The second 555 is of CN-type, and can oscillate up to a maximum frequency of
2.1 MHz. The output signal of this IC 555 CN is identical to its input (the
intermediate PWM signal) if the control pin has a voltage greater than 5.1 V and a
voltage near 0 V otherwise. The value of this threshold voltage (5.1 V in this design)
is set by the voltage divider connected to the threshold pin, taking into account the
following relations:
2
1 2+
OUT in
R
V V
R R
(1)
Considering R1=680 kΩ, R2 =510 kΩ and Vin=12V, one obtains VOUT=5.1 V.
C. DC-DC converter control
Two main methods can be used for controlling the duty cycle of the DC-DC converter
while keeping the output voltage within the desired range: the voltage control mode
and the current control mode.
In the voltage control mode, the output voltage is measured and compared with
the desired output voltage. An error is generated and amplified by a differential
amplifier and then it may be used in a comparison with a ramp signal to produce the
PWM signal [17].
The current control mode is implemented with the use of a sensing resistor or
current sensor in the secondary side of the transformer, in series with the load (see
Fig. 4). The current is measured and converted into a voltage signal being then
compared with a reference voltage. The reference voltage corresponds to a previously
converted current value (desired output current) [18]. An error signal is generated, and
after being suitably conditioned by a differential amplifier, a hysteretic control signal
is obtained producing the appropriate duty cycle [19].
The current control mode has greater flexibility with regard to limiting the output
current, a faster response to load variations, and offers the possibility of connecting
different DC-DC converters in parallel, with an easy management of the load sharing
[20]. Having this in mind, it was decided to use a current control mode in the DC-DC
converter here proposed.
The basic scheme of the designed current control system is shown in Fig. 7, where
a proportional controller is used to accelerate the response of the system to variations
in the reference (desired) output current.
CS Signal
LM6171 ISO124
3.3 nF
15 Ω
Output of
DSPACE
2.4 kΩ
2.4 KΩ
39 KΩ
39 KΩ
22 KΩ
22 KΩ
20 nF
VCC2
-VCC2
-
+
VCC2
-VCC2
VCC3
-VCC3
GND2
GND3
Figure 7 Diagram of the current control system
8. Fernando Santos, Humberto Jorge and Sérgio Cruz
http://www.iaeme.com/IJEET/index.asp 64 editor@iaeme.com
The current supplied to the load by the DC-DC converter is measured with a
CMS3005 Hall effect sensor that ensures the isolation between the secondary side of
the flyback transformer and the control circuitry. This sensor has a very high
bandwidth (2 MHz) and was connected in a serial configuration, allowing it to
measure currents ranging from -5 A to 5 A. When this sensor is powered with ±15 V
it provides an output voltage in the range of -10 V to 10 V. To reduce noise effects, a
low pass-filter with a cut-off frequency of 3 MHz is connected at the output terminals
of this current sensor.
A dSPACE platform generates a reference voltage signal between 0 V and 10 V,
corresponding to the reference (desired) load current delivered by the DC-DC
converter to the DC bus. The difference between the output voltage of the current
sensor and the reference voltage given by dSPACE is detected by a differential
amplifier LM6171 with a slew rate of 3600 V/μs and a bandwidth of 100 MHz, which
also performs the amplification of the error signal. Considering an offset error of 1
mV (0.02% error) introduced by the output channels of dSPACE, and an error of
2.47% (247 mV) introduced by the current sensor (in extreme conditions), plus some
safety margin, a maximum error of 250 mV was considered, which corresponds to an
error of 250 mV/10000 mV=2.5%.
Knowing that the IC 555 CN, with a voltage lower than 5.1 V in the voltage
control input does not generate any PWM signal in its output pin, one can draw the
diagram shown in Fig. 8.
Does not allow the
output of the
modulation
Allows the output of the modulation
0 V 5V 5,1V x=200V
2,5% 97,5%
Figure 8 Modeling a function for the voltage at the control input.
In practical terms, the LM6171 output voltage can never reach 15 V due to
saturation. Considering, for the differential amplifier, an input resistance Re of 2.4 kΩ,
and the relation
2 1-f
O
e
R
V V V
R
, (2)
Where OV is the voltage in the output (200 V), 2V is the maximum voltage that
may be applied at the inputs (10 V) and 1V is the minimum voltage value at the inputs
(0 V), one obtains a value of 48 kfR for the two output resistors of the differential
amplifier.
The signal obtained at the output of LM6771 is then isolated with an ISO124
precision isolation amplifier configured with a unit gain, thus obtaining the control
signal (CS signal) for the IC 555 CN.
D. Auxiliary power supplies
An aspect that cannot be neglected is the power supply of all electronics needed for
the generation of the control signals of the entire DC-DC converter. The three
auxiliary voltages needed, VCC1, VCC2 and VCC3, are obtained with the aid of auxiliary
DC-DC converters, as shown in Fig. 9. The entire supply system may be fed from a
variable input voltage in the range of 18-75 V.
9. Design of A Multifunctional Flyback Dc–Dc Converter with Current Control
http://www.iaeme.com/IJEET/index.asp 65 editor@iaeme.com
DC
18 to 75 V
VCC1
VCC2
GND2
-VCC2
VCC3
GND3
-VCC3
0.1 µF
30CTH03 30CTH03 30CTH03
10 µF 10 µF 10 µF 10 µF
GND1
Figure 9 Auxiliary power supply
In Fig. 9, the diodes 30CTH03 prevent the current flow in reverse direction and
the 10 μF capacitors on the left side of the auxiliary DC-DC converters ensure
protection and voltage stabilization. The capacitor of 10 μF on the output side of TEN
WI-4812, allows the stabilization of its output voltage around 12 V. This is important
for the proper generation of the PWM signal by the two oscillators with a frequency
of 200 kHz, whose value depends on the charge time and discharge time of the
capacitor of 3.3 nF.
The current sensor CCMS3005, the differential amplifier LM61171 and the input
stage of ISO124 are supplied with symmetrical voltages of Vcc2=±15 V, obtained with
the converter TEM 6-4823 WIN. It should be pointed out that this converter provides
full isolation between the input and output sides.
The output stage of ISO124 is fed by a third auxiliary symmetrical voltage of
Vcc3=±15 V.
E. RC Snubber for the MOSFET
DC-DC converters with PWM have not an ideal behavior, leading to voltage and
current waveforms with some oscillations that are primarily caused by the circuit
parasitic capacitances. These oscillations must be adequately suppressed, as they can
cause malfunctions or even the failure of the semiconductors (namely the MOSFET),
if they reach high levels [21].
In the following, a set of theoretical methods and practical techniques for the
design of a RC snubber circuit for the MOSFET are presented.
In a first step, the circuit was assembled without any snubber in parallel with the
MOSFET and without the limiting RCD network for the transformer, whose design
will be described in the next subsection.
The purpose of this test was to analyze the behavior of the voltage between the
drain and the source of the MOSFET (VDF). In this test, the DC-DC converter was
supplied with 18 V, with a resistive load of 1 kΩ connected to its output. The voltage
waveform corresponding to VDF was recorded with a Tektronix DPO 2014
oscilloscope, as shown in Fig. 10.
Figure 10 MOSFET Drain-to-source Voltage (VDF) without snubbers
10. Fernando Santos, Humberto Jorge and Sérgio Cruz
http://www.iaeme.com/IJEET/index.asp 66 editor@iaeme.com
The large high-frequency oscillations visible in the waveform shown above occur
due to the resonance between the inductance of the transformer and the parasitic
capacitances of the circuit. The goal now is to eliminate these oscillations in order to
prevent damages to the MOSFET, or even power oscillations on the transformer
secondary side.
A RC snubber is connected between the drain and the source of the MOSFET,
consisting in a series connection of a resistance, whose value must be chosen correctly
to dissipate the energy associated with the ripple, and a capacitor to ensure that the
power dissipated in the resistance is not excessive.
The sizing of the snubber components involves the measurement of inductance of
the transformer. For this purpose, a BK PRECISION 889A LCR meter was used, with
a short circuit is applied across the secondary of the transformer, and the impedance
being measured from the primary side. A value of -9
= 93 10 HL was obtained.
The ringing oscillation frequency was measured based on the VDF waveform (see
Fig. 10), being obtained a value of fr=12.5 MHz. The characteristic impedance of the
resonant circuit, given by Z=2πfrL, is 7.5 Ω. The ringing will be well damped if the
snubber resistance is set equal to the impedance of the resonant circuit R=Z. The
resistance used in practice was 6.8 Ω (5 W), value available on the market.
The impedance of the capacitor at the ringing frequency should be set equal to the
snubber resistance (C=1/(2πfrR)) [22]. Thus, the snubber capacitor C is chosen with
the value 1.74 nF. In practice, a value of 1.8 nF was used, which is available on the
market.
The power dissipated in the snubber can be calculated by [22]:
Psn=CV2
fs (3)
Considering that a drain-to-source voltage of the MOSFET, in normal operation,
less than 100 V, a capacitance C=1.8 nF and the switching frequency fs=200 kHz, a
power of Psn=3.6 W is calculated. In practice, a value of 5 W was chosen for the
power of the snubber resistor.
Fig. 11 shows the obtained results regarding the operation of the DC-DC
converter with the designed RC snubber. Comparing these results with the ones
shown in Fig. 10, it can be seen the effectiveness of this snubber, as the ringing is
almost absent.
Figure 11 MOSFET drain-to-source voltage with RC snubber.
11. Design of A Multifunctional Flyback Dc–Dc Converter with Current Control
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F. Primary RCD Clamp for Flyback Converter
An RCD clamp circuit is needed to absorb the energy stored in the transformer
leakage inductance once the MOSFET drain voltage exceeds the clamp capacitor
voltage.
Even with a very light load level in the converter, the capacitor will always be
charged up to the voltage reflected from the secondary side of the converter, Vf. As
the load level increases, more energy will flow into the capacitor, and the voltage will
rise by an additional amount, Vx, above the ideal square wave flyback voltage (Fig.
12).
The primary inductance of the transformer Lp@200 kHz is 42.855 μH. Since Ts
=1/(200x103
) s, in order to avoid the converter to leave the discontinuous mode, one
considered TON=0.48Ts=3.43×10-5
s.
Figure 12 Voltage in capacitor of the RCD limiter
The DC-DC converter to be designed is intended to have an output voltage Vdc=24
V. Hence, the peak primary current will be given by [22]
( -1)
1.29 Adc ON
p
P
V T
I
L
(4)
Considering a minimum input voltage Vin (min)=24 V, 50 VxV and 250 Vmáx
xV ,
where máx
xV is the maximum avalanche voltage VDS of the MOSFET, one obtains
(min)- - =176 Vmáx
f x x inV V V V (5)
The resistance can now be given by [20]:
max
2
2 (
876.3 k
)x s f x
sn
p
V T V V
R
LI
(6)
In practice, a value of 860 kΩ was adopted.
The snubber capacitor must be able to maintain the voltage constant while
absorbing energy, and may be calculated using the relation [23]:
,sn
sn
sn sn s
V
C
V R f
(7)
Where snV is the maximum allowed voltage variation, being normally set
between 5% and 10%. In this design, a value of 5% was considered.
The voltage snV can be seen from the secondary to the primary as 2.5×Vdc, where n
is the transformation ratio of the transformer. A value of CSn=1.03 μF is obtained, so
any value with higher capacity can be used. In the present design, a value of 75 μF
was adopted.
12. Fernando Santos, Humberto Jorge and Sérgio Cruz
http://www.iaeme.com/IJEET/index.asp 68 editor@iaeme.com
The power dissipated in the RCD clamp circuit is given by
2
( )x f
sn
V V
P
R
, (8)
thus obtaining a value of 58.28 mW.
G. Output filter capacitor
An output filter should be used in the DC-DC converter in order to obtain a stabilized
load voltage. In the flyback topology, the minimum output filter capacitor C0, is given
by [15]:
0
0
( - )s off
C
I T T
C
V
, (9)
where 0I is the maximum output current (considered as 2 A), offt is the blocking
time and CV is the allowed voltage variation in the capacitor, here considered as 5 mV.
The value obtained for 0C is 960 μF. In the present design, a value of 2000 μF was
used in practice.
5. EXPERIMENTAL VALIDATION
A. Laboratory prototype
Following the design rules presented in the previous section, a prototype of the
designed flyback DC-DC converter was constructed, as shown in Fig. 13.
Figure 13 Prototype of the flyback DC-DC converter.
This DC-DC converter was then tested, according to the test setup shown in Fig.
14.
24 V
DC-DC
CONVERTER
Voltage source
EA-PS 2084-10 B
Voltage source
Topward 6302 D18 - 75 V RC
IF1 IDC IF2
IC
Control of IDC through voltage
VDSP
Figure 14 Experimental setup for testing the DC-DC converter
13. Design of A Multifunctional Flyback Dc–Dc Converter with Current Control
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The input side of the DC-DC converter was connected to a voltage source of 24 V.
To emulate the real working conditions of each DC-DC converter when integrated
into the system shown in Fig. 1, a second voltage source of 24 V is connected to the
output side of the DC-DC converter under test. The role of this voltage source is to
impose a constant voltage to the common DC bus. Moreover, the output is also
connected to a resistive load Rc =16 Ω. The reference value of the DC-DC converter
output current (IDC in Fig. 14) is controlled with the aid of an adjustable voltage
source, whose output signal will serve as the basis for controlling IDC.
B. Experimental results
For each value of the adjustable voltage, different quantities were recorded, being
presented in Table II.
As can be seen, the current IDC is almost proportional to the control voltage VDSP,
which is what could be anticipated from the design stage of the DC-DC converter.
TABLE II Behavior of the DC-DC Converter for Different Values of the Controlled Output
Current
Control VDSP
(V)
IF1
(A)
IF2 (A)
IDC
(A)
DC-DC converter
efficiency (%)
0 0.08 1.49 0 0
0.1 0.09 1.48 0.01 11
0.2 0.09 1.47 0.02 23
0.3 0.18 1.42 0.07 39
0.4 0.42 1.25 0.23 57
0.5 0.59 1.12 0.37 62
0.6 0.82 0.96 0.53 65
0.7 1.15 0.74 0.72 63
0.8 1.47 0.63 0.84 57
0.9 1.78 0.49 0.98 55
1 2.21 0.27 1.15 52
The efficiency of this converter was also evaluated for different values of the
output current, and it is shown in the last column of Table II.
Considering the operation of the DC-DC converter between 0 A and 1 A, its
maximum efficiency is obtained typically in the range of 50-70 % of rated load.
Fig. 15 shows the input current and voltage waveforms obtained with the
converter operating at 40 % of rated load. One can see that while the voltage remains
approximately constant (it is imposed by the voltage source), the input current
waveform resembles a sawtooth due to the operation of the converter in discontinuous
mode.
Figure 15 Voltage and current at the converter input at 40% of rated load.
14. Fernando Santos, Humberto Jorge and Sérgio Cruz
http://www.iaeme.com/IJEET/index.asp 70 editor@iaeme.com
Fig. 16 and Fig. 17 show the output voltage and current waveforms for two
different DC-DC converter load levels. As can be seen, both waveforms are very
stable and follow the expected values.
Figure 16 Output voltage and current waveforms for an output reference current of 0.5 A.
Figure 17 Output voltage and current waveforms for an output reference current of 1 A.
Having validated the good steady-state behavior of the constructed DC-DC
converter, it is also important to test its dynamic behavior, namely its ability to track
quickly the reference value of the output current. With this purpose, the reference
voltage signal (which is proportional to the output reference current) is generated with
the dSPACE platform and a current step with an amplitude of 1 A is imposed at t=0 s.
The obtained results are shown in Fig. 18, and demonstrate that the converter only
needs a few tens of milliseconds to reach the desired output current. Given the needs
of the target application of this DC-DC converter, the response can be considered
almost instantaneous.
Figure 18 Dynamic response time of the DC-DC converter for a reference current step of 1
A.
6. CONCLUSION
This paper presents a set of design criteria for building flyback DC-DC converters for
the interconnection of different sources of renewable energy with energy storage
elements and flexible load profiles to a common DC bus. This power system requires
-0.1 -0.05 0 0.05 0.1 0.15 0.2 0.25 0.3
0
0.2
0.4
0.6
0.8
1
1.2
Time (S)
Current(A)
15. Design of A Multifunctional Flyback Dc–Dc Converter with Current Control
http://www.iaeme.com/IJEET/index.asp 71 editor@iaeme.com
the use of DC-DC converters with the ability to regulate the output power injected
into the DC bus through the regulation of their output currents.
For this purpose, a prototype of the designed DC-DC converter was built and
tested in the laboratory. The obtained results demonstrate a fast and accurate
regulation capability of the output current through the use of a voltage control signal
which, in practice, may be generated by an energy management system according to
some specific algorithms.
The proposed DC-DC converter exhibits a very good dynamic behavior and a
stable steady-state response, while ensuring isolation between its input side, output
side and control circuitry.
The presented design methodology was validated experimentally and can be easily
used in the design of flyback DC-DC converters for different purposes.
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