Abstract
This paper aims at the study of DIGITAL EXCITATION SYSTEM [Micro Controller based automatic voltage regulator] employed for
synchronous generators .The main component of the digital excitation system is the Automatic Voltage Regulator. This maintains the
machine terminal voltage in desired reference, which can be varied in order to accomplish different power system requirements .The
digital excitation system is developed from the digital signal processor whichwill capture of variables, performs mathematical
operations and control algorithms and sends the control signals to the actuator. Automatic Voltage regulator (automatic/manual
control), over excitation limiter, Under excitation limité and volts/hertz limiter are included in this digital excitation system. The
exciter is controlled three phase SCR’s bridge
Index Terms: DIGITAL EXCITATION SYSTEM, Automatic Voltage Regulator, SCR Bridge, synchronous
generator,dsPIC30F4012.
Modeling control of automatic voltage regulator with proportional integral de...eSAT Journals
This document summarizes a study that models the control of an Automatic Voltage Regulator (AVR) system using a Proportional Integral Derivative (PID) controller. The study creates a simulation model of an AVR controller using MATLAB/Simulink software. The simulation shows that adding a PID controller to the AVR results in a faster response time when loads change compared to using just the AVR with a proportional controller. With optimized PID constants, the voltage is restored to a stable level much quicker while experiencing less oscillation when loads fluctuate. Therefore, the study concludes that a PID controller is better suited than a proportional controller alone for controlling generator voltage with changing loads.
V/F Control of Squirrel Cage Induction Motor Drives Without Flux or Torque Me...Waqas Tariq
Based on the popular constant volts per hertz principle, two improvement techniques are presented: keeping maximum torque constant or keeping magnetic flux constant. An open-loop inverter-three-phase squirrel-cage induction motor drive system that provides constant maximum torque or increased maximum torque and reduced slip speed at frequencies below the nominal frequency has been modeled, simulated and tested. Load performance analysis of the proposed system under different operation conditions was provided. These principles of operation are extended to the case of operation from variable frequency or variable voltage control method. Finally, the effects of the non-sinusoidal voltage and/or current wave shapes are covered. The results show that both suggested improvement techniques (constant torque or constant flux) improve the steady-state performance A.C. drive system with squirrel cage induction motors. The slip speed has been decreased and the starting torque and maximum torque have been increased, which means that the suggested control techniques can be used in drive systems with short time operating mode under light loads.
This document proposes a direct torque control strategy for doubly fed induction machine-based wind turbines that can operate under voltage dips without crowbar protection. The control strategy generates a rotor flux amplitude reference to control the torque of the wind turbine and reduce stator and rotor overcurrents during faults. It also provides fast dynamic response. While the control does not eliminate the need for crowbar protection entirely, it can prevent the crowbar from activating during low-depth voltage dips. The direct torque control approach maintains machine connection to the grid and reduces torque oscillations during faults.
Implementation of ac induction motor control using constant vhz principle and...eSAT Journals
Abstract
This paper presents the hardware implementation of V/f control of induction motor using sine wave PWM method. Because of its
simplicity, the V/F control also called as the scalar control, is the most widely used speed control method in the industrial
applications. In this method the ratio between stator voltage to frequency is maintained constant so that the stator flux is
maintained constant. As the stator flux is maintained constant, the torque developed by the motor depends only on the slip speed
and is independent of the supply frequency. Thus we can control the speed and torque of induction motor by simply controlling the
slip speed of induction motor. The complete control is achieved with the help of TMS320F28027 Development Board. One of the
basic requirements of this scheme is the PWM inverter. The gating signals are generated using sine wave PWM technique.
Implementation issues such as PWM signal generation, ramp control, v/f control, inverter design are discussed. The results are
discussed based on the various waveforms.
KeyWords: v/f control, Induction motor, PWM, and Scalar control
Review of Improved Direct Torque Control Methodologies for Induction Motor Dr...AM Publications
ecoupled control of induction motor drives is possible using Direct Torque Control (DTC) method which
is very simple control strategy compared to field oriented control. In this method direct torque control is achieved by
selecting suitable inverter switching voltage vector from a lookup table. But drawback of this method is that it
produces toque ripples. Also the switching frequency of inverter switches is not constant. Many methods have been
proposed to address these issues of DTC. This paper reviews various methodologies which are suggested to improve
performance of basic DTC induction motor drive.
Single phasing of three phase induction motorJUNAID SK
This document is a lab report on experimentally studying the behavior of a three phase induction motor under normal and single phasing conditions. It includes an introduction to induction motors, three phase induction motors, and single phasing. The experimental setup section describes the aim, apparatus, theory, circuit diagram, procedure, observations, and conclusions from testing a three phase induction motor under normal and single phasing supply conditions. The report is submitted to fulfill requirements for a Bachelor of Technology degree.
PLC and Sensors Based Protection and Fault Detection of Induction MotorsMathankumar S
This document presents a new programmable logic controller (PLC)-based protection method for induction motors. The classical and computer-based protection methods have limitations like high cost, reduced accuracy, and lack of visualization. The proposed PLC-based method monitors motor parameters like voltage, current, speed, and temperature without the need for contactors, timers, or analog-to-digital conversion cards. It provides accurate, cost-effective protection with a visual interface to show warnings. The method uses components like current transformers, voltage transformers, sensors, and encoders to monitor the motor and send signals to the PLC.
Matrix Converter based Direct Torque Control of Induction MotorNeehar NLN
This topic falls under the area of speed control of induction motor. The using of advanced power electronic converters provides better response. In this case, a AC/AC converter is used to control the induction motor.
Modeling control of automatic voltage regulator with proportional integral de...eSAT Journals
This document summarizes a study that models the control of an Automatic Voltage Regulator (AVR) system using a Proportional Integral Derivative (PID) controller. The study creates a simulation model of an AVR controller using MATLAB/Simulink software. The simulation shows that adding a PID controller to the AVR results in a faster response time when loads change compared to using just the AVR with a proportional controller. With optimized PID constants, the voltage is restored to a stable level much quicker while experiencing less oscillation when loads fluctuate. Therefore, the study concludes that a PID controller is better suited than a proportional controller alone for controlling generator voltage with changing loads.
V/F Control of Squirrel Cage Induction Motor Drives Without Flux or Torque Me...Waqas Tariq
Based on the popular constant volts per hertz principle, two improvement techniques are presented: keeping maximum torque constant or keeping magnetic flux constant. An open-loop inverter-three-phase squirrel-cage induction motor drive system that provides constant maximum torque or increased maximum torque and reduced slip speed at frequencies below the nominal frequency has been modeled, simulated and tested. Load performance analysis of the proposed system under different operation conditions was provided. These principles of operation are extended to the case of operation from variable frequency or variable voltage control method. Finally, the effects of the non-sinusoidal voltage and/or current wave shapes are covered. The results show that both suggested improvement techniques (constant torque or constant flux) improve the steady-state performance A.C. drive system with squirrel cage induction motors. The slip speed has been decreased and the starting torque and maximum torque have been increased, which means that the suggested control techniques can be used in drive systems with short time operating mode under light loads.
This document proposes a direct torque control strategy for doubly fed induction machine-based wind turbines that can operate under voltage dips without crowbar protection. The control strategy generates a rotor flux amplitude reference to control the torque of the wind turbine and reduce stator and rotor overcurrents during faults. It also provides fast dynamic response. While the control does not eliminate the need for crowbar protection entirely, it can prevent the crowbar from activating during low-depth voltage dips. The direct torque control approach maintains machine connection to the grid and reduces torque oscillations during faults.
Implementation of ac induction motor control using constant vhz principle and...eSAT Journals
Abstract
This paper presents the hardware implementation of V/f control of induction motor using sine wave PWM method. Because of its
simplicity, the V/F control also called as the scalar control, is the most widely used speed control method in the industrial
applications. In this method the ratio between stator voltage to frequency is maintained constant so that the stator flux is
maintained constant. As the stator flux is maintained constant, the torque developed by the motor depends only on the slip speed
and is independent of the supply frequency. Thus we can control the speed and torque of induction motor by simply controlling the
slip speed of induction motor. The complete control is achieved with the help of TMS320F28027 Development Board. One of the
basic requirements of this scheme is the PWM inverter. The gating signals are generated using sine wave PWM technique.
Implementation issues such as PWM signal generation, ramp control, v/f control, inverter design are discussed. The results are
discussed based on the various waveforms.
KeyWords: v/f control, Induction motor, PWM, and Scalar control
Review of Improved Direct Torque Control Methodologies for Induction Motor Dr...AM Publications
ecoupled control of induction motor drives is possible using Direct Torque Control (DTC) method which
is very simple control strategy compared to field oriented control. In this method direct torque control is achieved by
selecting suitable inverter switching voltage vector from a lookup table. But drawback of this method is that it
produces toque ripples. Also the switching frequency of inverter switches is not constant. Many methods have been
proposed to address these issues of DTC. This paper reviews various methodologies which are suggested to improve
performance of basic DTC induction motor drive.
Single phasing of three phase induction motorJUNAID SK
This document is a lab report on experimentally studying the behavior of a three phase induction motor under normal and single phasing conditions. It includes an introduction to induction motors, three phase induction motors, and single phasing. The experimental setup section describes the aim, apparatus, theory, circuit diagram, procedure, observations, and conclusions from testing a three phase induction motor under normal and single phasing supply conditions. The report is submitted to fulfill requirements for a Bachelor of Technology degree.
PLC and Sensors Based Protection and Fault Detection of Induction MotorsMathankumar S
This document presents a new programmable logic controller (PLC)-based protection method for induction motors. The classical and computer-based protection methods have limitations like high cost, reduced accuracy, and lack of visualization. The proposed PLC-based method monitors motor parameters like voltage, current, speed, and temperature without the need for contactors, timers, or analog-to-digital conversion cards. It provides accurate, cost-effective protection with a visual interface to show warnings. The method uses components like current transformers, voltage transformers, sensors, and encoders to monitor the motor and send signals to the PLC.
Matrix Converter based Direct Torque Control of Induction MotorNeehar NLN
This topic falls under the area of speed control of induction motor. The using of advanced power electronic converters provides better response. In this case, a AC/AC converter is used to control the induction motor.
Analysis and Simulation of Asynchronous Machine Connected with Load Accomplis...YogeshIJTSRD
This paper presents the simulation analysis of pulse width modulation based induction motor drive. The main objective of this paper is analysis of asynchronous machine with PWM fed inverter and harmonic analysis of active and reactive power as well as voltage and current. Space vector pulse width modulation technique is used in various industrial applications. Variation in voltage and frequency supply to ac drives is produced from a voltage source inverter and space vector PWM is used frequently now a day due to their easy understanding. This work is based on a SVPWM based induction motor based on space vector theory. The simulation is done on MATLAB software and the simulation results obtained and analyzed. Ms. Neetu Khunte | Mr. Abhijeet Lal | Mr. Abhishek Agrawal "Analysis and Simulation of Asynchronous Machine Connected with Load Accomplished with Chopper Control and PWM Based Inverter" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-4 , June 2021, URL: https://www.ijtsrd.compapers/ijtsrd41190.pdf Paper URL: https://www.ijtsrd.comengineering/electronics-and-communication-engineering/41190/analysis-and-simulation-of-asynchronous-machine-connected-with-load-accomplished-with-chopper-control-and-pwm-based-inverter/ms-neetu-khunte
Direct torque control of induction motor using space vector modulationIAEME Publication
This document discusses direct torque control of an induction motor using space vector modulation. It begins with introducing direct torque control as an alternative to field oriented control for controlling torque and flux directly and independently. It then provides details on the principles of vector control and direct torque control in stator reference frames. The document describes the modeling of an induction motor and simulations performed in MATLAB to validate the direct torque control approach. The simulations demonstrate control of speed, torque, and flux under different gain settings of the PI controller.
Controlling power flow losses in upfc system using adaptive neuro fuzzy contr...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.
induction motor protection system seminar reportdipali karangale
The document describes an induction motor protection system that protects the motor from single phasing, overheating, over voltage, and under voltage. It uses current transformers connected to a microcontroller to monitor the motor's current on each phase. If one phase is missing or the temperature exceeds a threshold, the microcontroller cuts power to the motor. It also uses voltage comparators and a variable resistor to protect against over and under voltage by disconnecting power if the supply voltage is too high or low.
speed control of three phase induction motor using IOTswaroop009
This project controls and monitors the speed of a three-phase induction motor using an Arduino and Node MCU controller. The Arduino implements PWM to control the motor speed using a three-phase driver circuit. Node MCU is used to increase and decrease the speed and establishes feedback of the speed to the Node MCU, which transmits the signal over Wi-Fi. This allows remote control of the motor speed through an IP address. The hardware components include a power supply, transformer, rectifier, inverter, driver circuit, Node MCU, Arduino and connecting wires. MATLAB is used to simulate the three-phase inverter and hardware results are obtained.
Induction motor fault diagnosis by motor current signature analysis and neura...Editor Jacotech
This paper presents steps in designing dimensions of antenna and feed in axisymmetrical Cassegrain Antennas. Corrugated conical horns are used as feeds in applications with circular polarization. In the initial design steps, diameter of the main reflector is determined considering communication link budget, then feed dimensions are designed to create optimum aperture efficiency. In the last step of design, considering feed dimensions and the amount of its center phase displacements with respect to its aperture plane, dimensions of subreflector is determined to avoid additional blockage. To illustrate the procedure, an applicative design example is presented in X-band.
1. direct torque control of induction motor with fuzzy controller a reviewMajdi Dadeq
This document reviews direct torque control of induction motors with fuzzy controllers. It begins by providing background on induction motors and their widespread use in industry. It then discusses direct torque control, which aims to directly control the stator flux and torque of induction motors through optimal selection of inverter switching vectors. The rest of the document discusses modeling induction motor drives using direct torque control with fuzzy logic applications and compares various techniques that have been proposed.
Simulation of Direct Torque Control of Induction motor using Space Vector Mo...IJMER
This document presents a simulation of direct torque control (DTC) of an induction motor using space vector modulation (SVM). It begins with an introduction to DTC and its advantages over field oriented control. It then describes the induction motor model and equations used in the simulation. The paper explains the DTC-SVM scheme, including flux and torque estimation, hysteresis controllers, voltage vector selection, and the simulation developed in MATLAB. The results show uniform torque production with reduced ripple compared to without DTC control. In conclusion, DTC-SVM provides improved dynamic performance over conventional DTC.
Analysis and control of four quadrant operation of three phase brushless dc (...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
Design of drive for speed control of induction pptAvinash Varanasi
This document presents a project to control the speed of an induction motor using a variable frequency/variable voltage (V/F) method. The project team includes 6 members and is guided by Arun Kumar. The system uses a microcontroller to provide easy control over and adjustable speed capability for the induction motor. It consists of electronic components, a microcontroller, and an LCD display. The motor speed can be selected and adjusted to user-defined speeds under various load conditions, with the V/F ratio maintained constant to keep the air gap flux stable. Experimental results showing motor speed at different voltages, frequencies and loads are presented in a table.
Stator flux oriented vector control of wind driven self excited induction gen...Alexander Decker
This document discusses stator flux oriented vector control of a wind-driven self-excited induction generator connected to the grid through a cycloconverter. A MATLAB/Simulink model is developed to simulate the system. Key points:
1. A stator flux oriented control scheme is used to regulate the voltage and frequency of the self-excited induction generator.
2. A cycloconverter is used to interface the generator output to the grid, which helps eliminate harmonics but results in lower output voltage. This is compensated using a step-up transformer.
3. Simulation results under load and fault conditions like sudden load and short circuit are presented to demonstrate the effectiveness of the proposed control method in regulating
The document summarizes research on using space vector modulation (SVM) for speed control of an induction motor driven by a three-phase inverter. It compares SVM to sine triangle pulse width modulation (SPWM) and finds that SVM provides better harmonic performance, higher DC bus utilization, and a more sinusoidal output voltage. The document simulates v/f control of an induction motor using SVM for both open-loop and closed-loop speed control systems. It is observed that the induction motor's performance is improved with SVM compared to SPWM modulation.
Updated field oriented control of induction motor.pptxMohit Sharma
It is a simulation work project done on a 5hp,440V/5A and 1440rpm Induction motor.It explains the control of induction motor using matlab-simulink algorithm by PI control as well as Fuzzy logic control.
This document discusses various components used in robotics including electric motors, sensors, voltage regulators, and H-bridges. It describes how electric motors convert electrical energy to mechanical energy and lists common types like brushed DC motors, brushless DC motors, stepper motors, and servo motors. Sensors are outlined as playing a key role in robotics by allowing robots to maintain stability, report position/speed, interact with surroundings, distinguish objects, and mimic human senses. Voltage regulators are defined as devices that maintain a constant voltage level and various types are identified. H-bridges are described as circuits for controlling DC motor direction. Potential future applications of robotics discussed include expanded use in industrial, military, medical, and space
Induction motor modelling and applicationsUmesh Dadde
A three-phase induction motor is one of the most popular and versatile motor in electrical
power system and industries. It can perform the best when operated using a balanced three-phase
supply of the correct frequency. In spite of their robustness they do occasionally fail and their
resulting unplanned downtime can prove very costly. Therefore, condition monitoring of
electrical machines has received considerable attention in recent years.
A servo amplifier is an electronic amplifier used to power electric servomechanisms. It monitors feedback from the servomechanism and adjusts for deviations from expected behavior. Servo drives have historically used different motor types including DC, brushless DC, synchronous, and asynchronous motors. A servo drive receives a command signal, amplifies it, and transmits current to a servo motor to produce proportional motion. Servo systems are used in CNC machining, factory automation, and robotics due to the addition of motor feedback over traditional motors.
This document describes an experiment to characterize the performance of a doubly-excited synchronous motor and generator. Tests are conducted to determine equivalent circuit parameters, torque, and power factor control. The synchronous machine's behavior is studied by varying the field current and load and measuring voltage, current, power factor, and torque. Equivalent circuit models are developed and parameters like reactance are calculated from no-load and short-circuit tests.
Control of variable reluctance machine (8/6) by artificiel intelligence techn...IJECEIAES
The non-linearity of variable-Reluctance Machine (8/6) and the dependence of machine inductance on rotor position and applied current complicate the development of the control strategies of drives using variable-Reluctance Machine variable-Reluctance Machine (VRM). The classical-control algorithms for example of derived full proportional action may prove sufficient if the requirements on the accuracy and performance of systems are not too strict. In the opposite case and particularly when the controlled part is submitted to strong nonlinearity and to temporal variations, control techniques must be designed which ensure the robustness of the process with respect to the uncertainties on the parameters and their variations. These techniques include artificial-intelligence-based techniques constituted of neural networks and fuzzy logic. This technique has the ability to replace PID regulators by nonlinear ones using the human brain’s reasoning and functioning and is simulated by using MATLAB/Simulink software. Finally, by using obtained waveforms, these results will be compared.
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
Modeling & analysis of standalone photovoltaic systemeSAT Journals
Abstract This paper represents the three phase Photovoltaic system connected with variable load in a standalone mode’s mathematical modeling using MATLAB/ Simulink environment. The system consist of a PV Array, Boost converter, three phase inverter and its control to maintain load in standalone mode. The 40 kW systems at the college site is under the study with a variable inductive load of 30kW which has to be fed by PV system in continuous mode .This paper gives analysis of each components of system while maintaining the load. The constant and boosted DC voltage is obtained with the help of boost converter from PV Array. The three phase IGBT inverter PWM control scheme is proposed here to normalize the voltage imbalance during variable load. Keywords: Photovoltaic System, Boost Converter, IGBT Inverter, and PI Controller etc…
This document describes the design of a wind power generation system using a permanent magnet synchronous machine, boost regulator, and transformer-less step down circuit. The system consists of a wind turbine connected to a permanent magnet synchronous generator. The output is rectified and boosted to the desired voltage level. An H-bridge inverter then converts the DC to AC. A novel control method uses both sinusoidal pulse width modulation and a square wave to reduce switching losses. Simulation results show this transformer-less design reduces harmonics to less than 0.1%.
ANN Approach for Fault Classification in Induction Motors using Current and V...IRJET Journal
This document discusses using an artificial neural network (ANN) approach to classify faults in induction motors based on current and voltage signals. It proposes using negative sequence current and swing angle values extracted from motor signals as inputs to a multi-layer perceptron ANN for fault classification. The faults considered are the healthy condition, rotor broken bar fault, and stator inter-turn short circuit fault. Experimental data was collected from a test motor under these different conditions to train and evaluate the ANN's performance at fault classification.
Analysis and Simulation of Asynchronous Machine Connected with Load Accomplis...YogeshIJTSRD
This paper presents the simulation analysis of pulse width modulation based induction motor drive. The main objective of this paper is analysis of asynchronous machine with PWM fed inverter and harmonic analysis of active and reactive power as well as voltage and current. Space vector pulse width modulation technique is used in various industrial applications. Variation in voltage and frequency supply to ac drives is produced from a voltage source inverter and space vector PWM is used frequently now a day due to their easy understanding. This work is based on a SVPWM based induction motor based on space vector theory. The simulation is done on MATLAB software and the simulation results obtained and analyzed. Ms. Neetu Khunte | Mr. Abhijeet Lal | Mr. Abhishek Agrawal "Analysis and Simulation of Asynchronous Machine Connected with Load Accomplished with Chopper Control and PWM Based Inverter" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-4 , June 2021, URL: https://www.ijtsrd.compapers/ijtsrd41190.pdf Paper URL: https://www.ijtsrd.comengineering/electronics-and-communication-engineering/41190/analysis-and-simulation-of-asynchronous-machine-connected-with-load-accomplished-with-chopper-control-and-pwm-based-inverter/ms-neetu-khunte
Direct torque control of induction motor using space vector modulationIAEME Publication
This document discusses direct torque control of an induction motor using space vector modulation. It begins with introducing direct torque control as an alternative to field oriented control for controlling torque and flux directly and independently. It then provides details on the principles of vector control and direct torque control in stator reference frames. The document describes the modeling of an induction motor and simulations performed in MATLAB to validate the direct torque control approach. The simulations demonstrate control of speed, torque, and flux under different gain settings of the PI controller.
Controlling power flow losses in upfc system using adaptive neuro fuzzy contr...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.
induction motor protection system seminar reportdipali karangale
The document describes an induction motor protection system that protects the motor from single phasing, overheating, over voltage, and under voltage. It uses current transformers connected to a microcontroller to monitor the motor's current on each phase. If one phase is missing or the temperature exceeds a threshold, the microcontroller cuts power to the motor. It also uses voltage comparators and a variable resistor to protect against over and under voltage by disconnecting power if the supply voltage is too high or low.
speed control of three phase induction motor using IOTswaroop009
This project controls and monitors the speed of a three-phase induction motor using an Arduino and Node MCU controller. The Arduino implements PWM to control the motor speed using a three-phase driver circuit. Node MCU is used to increase and decrease the speed and establishes feedback of the speed to the Node MCU, which transmits the signal over Wi-Fi. This allows remote control of the motor speed through an IP address. The hardware components include a power supply, transformer, rectifier, inverter, driver circuit, Node MCU, Arduino and connecting wires. MATLAB is used to simulate the three-phase inverter and hardware results are obtained.
Induction motor fault diagnosis by motor current signature analysis and neura...Editor Jacotech
This paper presents steps in designing dimensions of antenna and feed in axisymmetrical Cassegrain Antennas. Corrugated conical horns are used as feeds in applications with circular polarization. In the initial design steps, diameter of the main reflector is determined considering communication link budget, then feed dimensions are designed to create optimum aperture efficiency. In the last step of design, considering feed dimensions and the amount of its center phase displacements with respect to its aperture plane, dimensions of subreflector is determined to avoid additional blockage. To illustrate the procedure, an applicative design example is presented in X-band.
1. direct torque control of induction motor with fuzzy controller a reviewMajdi Dadeq
This document reviews direct torque control of induction motors with fuzzy controllers. It begins by providing background on induction motors and their widespread use in industry. It then discusses direct torque control, which aims to directly control the stator flux and torque of induction motors through optimal selection of inverter switching vectors. The rest of the document discusses modeling induction motor drives using direct torque control with fuzzy logic applications and compares various techniques that have been proposed.
Simulation of Direct Torque Control of Induction motor using Space Vector Mo...IJMER
This document presents a simulation of direct torque control (DTC) of an induction motor using space vector modulation (SVM). It begins with an introduction to DTC and its advantages over field oriented control. It then describes the induction motor model and equations used in the simulation. The paper explains the DTC-SVM scheme, including flux and torque estimation, hysteresis controllers, voltage vector selection, and the simulation developed in MATLAB. The results show uniform torque production with reduced ripple compared to without DTC control. In conclusion, DTC-SVM provides improved dynamic performance over conventional DTC.
Analysis and control of four quadrant operation of three phase brushless dc (...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
Design of drive for speed control of induction pptAvinash Varanasi
This document presents a project to control the speed of an induction motor using a variable frequency/variable voltage (V/F) method. The project team includes 6 members and is guided by Arun Kumar. The system uses a microcontroller to provide easy control over and adjustable speed capability for the induction motor. It consists of electronic components, a microcontroller, and an LCD display. The motor speed can be selected and adjusted to user-defined speeds under various load conditions, with the V/F ratio maintained constant to keep the air gap flux stable. Experimental results showing motor speed at different voltages, frequencies and loads are presented in a table.
Stator flux oriented vector control of wind driven self excited induction gen...Alexander Decker
This document discusses stator flux oriented vector control of a wind-driven self-excited induction generator connected to the grid through a cycloconverter. A MATLAB/Simulink model is developed to simulate the system. Key points:
1. A stator flux oriented control scheme is used to regulate the voltage and frequency of the self-excited induction generator.
2. A cycloconverter is used to interface the generator output to the grid, which helps eliminate harmonics but results in lower output voltage. This is compensated using a step-up transformer.
3. Simulation results under load and fault conditions like sudden load and short circuit are presented to demonstrate the effectiveness of the proposed control method in regulating
The document summarizes research on using space vector modulation (SVM) for speed control of an induction motor driven by a three-phase inverter. It compares SVM to sine triangle pulse width modulation (SPWM) and finds that SVM provides better harmonic performance, higher DC bus utilization, and a more sinusoidal output voltage. The document simulates v/f control of an induction motor using SVM for both open-loop and closed-loop speed control systems. It is observed that the induction motor's performance is improved with SVM compared to SPWM modulation.
Updated field oriented control of induction motor.pptxMohit Sharma
It is a simulation work project done on a 5hp,440V/5A and 1440rpm Induction motor.It explains the control of induction motor using matlab-simulink algorithm by PI control as well as Fuzzy logic control.
This document discusses various components used in robotics including electric motors, sensors, voltage regulators, and H-bridges. It describes how electric motors convert electrical energy to mechanical energy and lists common types like brushed DC motors, brushless DC motors, stepper motors, and servo motors. Sensors are outlined as playing a key role in robotics by allowing robots to maintain stability, report position/speed, interact with surroundings, distinguish objects, and mimic human senses. Voltage regulators are defined as devices that maintain a constant voltage level and various types are identified. H-bridges are described as circuits for controlling DC motor direction. Potential future applications of robotics discussed include expanded use in industrial, military, medical, and space
Induction motor modelling and applicationsUmesh Dadde
A three-phase induction motor is one of the most popular and versatile motor in electrical
power system and industries. It can perform the best when operated using a balanced three-phase
supply of the correct frequency. In spite of their robustness they do occasionally fail and their
resulting unplanned downtime can prove very costly. Therefore, condition monitoring of
electrical machines has received considerable attention in recent years.
A servo amplifier is an electronic amplifier used to power electric servomechanisms. It monitors feedback from the servomechanism and adjusts for deviations from expected behavior. Servo drives have historically used different motor types including DC, brushless DC, synchronous, and asynchronous motors. A servo drive receives a command signal, amplifies it, and transmits current to a servo motor to produce proportional motion. Servo systems are used in CNC machining, factory automation, and robotics due to the addition of motor feedback over traditional motors.
This document describes an experiment to characterize the performance of a doubly-excited synchronous motor and generator. Tests are conducted to determine equivalent circuit parameters, torque, and power factor control. The synchronous machine's behavior is studied by varying the field current and load and measuring voltage, current, power factor, and torque. Equivalent circuit models are developed and parameters like reactance are calculated from no-load and short-circuit tests.
Control of variable reluctance machine (8/6) by artificiel intelligence techn...IJECEIAES
The non-linearity of variable-Reluctance Machine (8/6) and the dependence of machine inductance on rotor position and applied current complicate the development of the control strategies of drives using variable-Reluctance Machine variable-Reluctance Machine (VRM). The classical-control algorithms for example of derived full proportional action may prove sufficient if the requirements on the accuracy and performance of systems are not too strict. In the opposite case and particularly when the controlled part is submitted to strong nonlinearity and to temporal variations, control techniques must be designed which ensure the robustness of the process with respect to the uncertainties on the parameters and their variations. These techniques include artificial-intelligence-based techniques constituted of neural networks and fuzzy logic. This technique has the ability to replace PID regulators by nonlinear ones using the human brain’s reasoning and functioning and is simulated by using MATLAB/Simulink software. Finally, by using obtained waveforms, these results will be compared.
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
Modeling & analysis of standalone photovoltaic systemeSAT Journals
Abstract This paper represents the three phase Photovoltaic system connected with variable load in a standalone mode’s mathematical modeling using MATLAB/ Simulink environment. The system consist of a PV Array, Boost converter, three phase inverter and its control to maintain load in standalone mode. The 40 kW systems at the college site is under the study with a variable inductive load of 30kW which has to be fed by PV system in continuous mode .This paper gives analysis of each components of system while maintaining the load. The constant and boosted DC voltage is obtained with the help of boost converter from PV Array. The three phase IGBT inverter PWM control scheme is proposed here to normalize the voltage imbalance during variable load. Keywords: Photovoltaic System, Boost Converter, IGBT Inverter, and PI Controller etc…
This document describes the design of a wind power generation system using a permanent magnet synchronous machine, boost regulator, and transformer-less step down circuit. The system consists of a wind turbine connected to a permanent magnet synchronous generator. The output is rectified and boosted to the desired voltage level. An H-bridge inverter then converts the DC to AC. A novel control method uses both sinusoidal pulse width modulation and a square wave to reduce switching losses. Simulation results show this transformer-less design reduces harmonics to less than 0.1%.
ANN Approach for Fault Classification in Induction Motors using Current and V...IRJET Journal
This document discusses using an artificial neural network (ANN) approach to classify faults in induction motors based on current and voltage signals. It proposes using negative sequence current and swing angle values extracted from motor signals as inputs to a multi-layer perceptron ANN for fault classification. The faults considered are the healthy condition, rotor broken bar fault, and stator inter-turn short circuit fault. Experimental data was collected from a test motor under these different conditions to train and evaluate the ANN's performance at fault classification.
Igbt based on vector control of induction motor driveeSAT Journals
Abstract
Generally, induction motor is fed by Current supply Inverter (CSI). During this project, hybrid model during which CSI area unit
accustomed feed the induction motor, are introduced. CSI employed in this work is SCR primarily based device. the standard gate
turn-off thyristor (GTO) primarily based CSI-fed induction motor drives suffer from draw- backs like low-frequency torsion pulsation,
harmonic heating and unstable operation at low-speed ranges. so as to beat these drawbacks, STATCOM is an efficient answer for
facing such power quality issues. This report deals with one in all the potential applications of Static Synchronous Compensator
(STATCOM) to industrial systems for mitigation of voltage dip drawback. The dip in voltage is mostly encountered throughout the
beginning of Associate in nursing induction motor. The model of STATCOM connected in shunt configuration to a 3 part supply
feeding dynamic motor masses is developed exploitation Simulink of MATLAB software package. Simulated results demonstrate that
STATCOM may be thought-about as a viable answer for finding such voltage dip issues. This thesis work aims at developing a
STATCOM for induction machines with reduced voltage dip.
Keywords: STATCOM, CSI,
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
Performance analysis of a single phase ac voltage controller under induction ...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.
Control of inverters to support bidirectional power flow in grid connected sy...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.
IRJET- Automated Flow Control in Solid Material Packaging MachinesIRJET Journal
This document discusses automating the filling process in solid materials packaging machines using an electromagnetic vibratory feeder controlled via phase angle control. The vibratory feeder uses a vibratory motor attached to an unbalanced mass to create vibrations for moving materials. A load cell measures the weight of materials being filled and provides a signal to a microcontroller. The microcontroller uses pulse width modulation to trigger thyristors that control the phase angle of the power supplied to the vibratory motor. This allows precise control of motor speed and vibration amplitude for automated filling based on weight measurements from the load cell. Phase angle control provides flexibility to automate the filling process and reduce labor requirements for monitoring in packaging applications.
Design of a wind power generation system using a permanent magnet synchronous...eSAT Journals
Abstract This paper presents a wind power system using a Permanent Magnet Synchronous Machine (PMSM). The whole system consists of a wind turbine, a permanent magnet synchronous machine, a three phase diode rectifier, a boost converter, a transformer-less step down circuit, an H-bridge inverter and a T-LCL filter. The 3-phase AC output from the PMSM is sent to the 3-phase diode rectifier for conversion to DC and a boost regulator is used to step-up this DC voltage to the desired level. This step-upped DC voltage is then converted into AC output by the H-Bridge inverter. The switching technique of the proposed inverter consists of a combination of Sinusoidal Pulse Width Modulation (SPWM) and a square wave along with grid synchronization conditions. As the suggested method is entirely transformer-less, it significantly reduces Total Harmonic Distortion (THD) to less than 0.1% and minimizes its size. The T-LCL Immittance Converter not only reduces the harmonics of the inverter output but also provides a nearly constant output current thereby stabilizing the system. The system setup and the simulation results were obtained using the PSIM software. Keywords: Wind Turbine, Permanent Magnet Synchronous Machine, Boost Converter, Step- down Circuit, T-LCL Immittance Converter, Inverter
IRJET- PIC Microcontroller based AC Voltage Stabilizer using Power Electr...IRJET Journal
1) Researchers designed a microcontroller-based AC voltage stabilizer using power electronic converters instead of a transformer to provide more accurate and efficient voltage regulation.
2) The system uses a rectifier, buck-boost converter, and inverter along with a microcontroller to maintain a constant output voltage despite fluctuations in the input voltage or load.
3) Simulation results showed that the system can successfully operate in buck mode to reduce an input voltage of 230V to 220V and in boost mode to increase an input of 200V to the desired 220V output.
Study On Speed Control of DC MOTOR Using ThyristorIRJET Journal
This document discusses speed control of a DC motor using a thyristor. It first provides background on DC motors and thyristors. It then presents the mathematical model of a separately excited DC motor. Various methods for controlling DC motor speed are described, including armature voltage control, armature resistance control, and flux control. Single phase half wave, full wave, and dual converter drives are introduced as techniques for implementing thyristor-based speed control. A simulation model is presented to observe the effect of varying the firing angle of a single phase full converter on the torque-speed characteristic of the DC motor. The document concludes that thyristor-based drives can effectively control DC motor speed.
Increase productivity and absorption of reactive power for power station with...IJITCA Journal
In this article, a new method of reactive power compensation for Synchronous generator power stations by
using static reactive power compensator provided. The advantages of this methodis used for control
voltage transmission is removing capacitors and reactors power station that their changing great voltage
and current transients in the power system. Also using of this compensator will improve automatic voltage
regulator function (AVR).
IRJET- Vector Control of Three Phase Induction MotorIRJET Journal
This document discusses vector control of a three-phase induction motor. Vector control, also called field-oriented control, allows independent control of torque and flux in induction motors, similar to DC motors. The document describes:
1) How vector control works by transforming stator currents into orthogonal d-q components representing flux and torque.
2) The principle of field-oriented control which locks the d-q reference frame to the rotor flux vector for decoupled control of flux and torque.
3) The simulation model built in MATLAB/Simulink to test vector control, including blocks for Clarke/Park transformations, current control, and a PI speed controller.
Performance Analysis Of Induction Motor For Voltage Mode And Current Mode Con...IRJET Journal
This document discusses the performance analysis of an induction motor using voltage mode and current mode control. It compares hysteresis current control and space vector pulse width modulation (SVPWM). Hysteresis control directly limits current peaks but SVPWM provides higher voltage output and lower harmonic distortion. The document simulates an induction motor drive using SVPWM-based hysteresis current control in MATLAB. Key steps include Clark transformation to generate reference signals, switching between active and zero vectors to synthesize the reference signal, and using hysteresis control to generate PWM signals from current errors. Simulation results show the SVPWM controller provides good speed and current regulation for the induction motor.
IRJET- Performance Analysis of Induction Motor using IoTIRJET Journal
This document describes a system for monitoring the performance of induction motors using IoT. Sensors are used to measure parameters like temperature, voltage, and vibration of operating induction motors. An Arduino microcontroller collects data from the sensors and sends it over WiFi to a cloud database. The system can detect abnormal conditions like undervoltage, overvoltage, or high vibration/temperature. When faults are detected, the Arduino sends a signal to shut off the motor. This allows remote monitoring of motor performance and automatic protection against operating faults to improve reliability and reduce downtime. Test results confirmed the system's ability to successfully monitor induction motors using IoT technology.
USE OF ARNO CONVERTER AND MOTOR-GENERATOR SET TO CONVERT A SINGLE-PHASE AC SU...IAEME Publication
This method is used to control the speed of a three-phase induction motor by using a three-phase to three-phase cycloconverter from a single-phase supply and to compare the use of ARNO converter and motor-generator set to convert a single-phase supply to a three-phase supply. ARNO converter is a rotating device which convert single-phase AC to three-phase AC. The three-phase supply needed for the three-phase induction motors which used in blowers, exhausters an oil pumps. A motor-generator set is a device for converting electrical power to another form. They are used to convert frequency, voltage or phase of power. Thus, both ARNO converter and motor-generator set have been used here one at a time to convert a single-phase AC supply to three-phase AC. Both have their own advantages and disadvantages
Investigation in Induction Motor Starting and Speed Control with Variable Fre...IRJET Journal
This document investigates induction motor starting and speed control using a variable frequency drive (VFD). It begins with an introduction to induction motors and why VFDs are commonly used for speed control. It then describes the components and operation of a basic VFD system, including the rectifier, DC link, and PWM inverter stages. The document presents the theoretical basis for induction motor speed control via frequency variation and discusses pulse width modulation techniques used in VFDs. Experimental results are referenced but not described. Overall, the document provides a high-level overview of using a VFD for induction motor starting and variable speed control.
The compensatation of unbalanced 3 phase currents in transmission systems on ...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.
The compensatation of unbalanced 3 phase currents in transmission systems on ...eSAT Journals
Abstract It is self-possessed of the Distributed Power Flow Controller is a new device within the family of FACTS. Power Quality is becoming an important issue for both electric utilities and end users. So the paper concentrate on one of the issue of power quality that is voltage sag compensation. My paper deals with the operation principle of a Practical Design and Implementation Procedure of Utilize Distributed Power Flow Controller (DPFC) to Compensate Unbalanced 3-phase Currents in Transmissions Systems. The series converters of the DPFC are single phase, the DPFC can compensate both active and reactive, zero and negative sequence unbalanced currents. To compensate the unbalance, two additional current controllers are supplemented to control the zero and negative sequence current respectively. FACTS devices can be employed to compensate the unbalanced currents and voltages in transmission systems. Unfortunately, it is found that the capability of most of FACTS devices to compensating unbalance is limited. Series and shunt FACTS device can only provide compensation of unbalanced reactive currents and the most powerful device – the UPFC cannot compensate zero-sequence unbalance current, because of the converter topology. My paper will show that the so-called DPFC can compensate both active and reactive, zero and negative sequence unbalanced currents. My paper consists of both active and reactive variations, using MATLAB/SIMULINK is simulated and its effects on the transmission lines observed. The simulated results are analyzed and validated with the real time results for the system considered Index Terms: AC–DC power conversion, filters, load flow control, power electronics, power-transmission control, power semiconductor devices, Power system control V-I measurements
Similar to Analytical study and implementation of digital excitation system for diesel generators (20)
Mechanical properties of hybrid fiber reinforced concrete for pavementseSAT Journals
Abstract
The effect of addition of mono fibers and hybrid fibers on the mechanical properties of concrete mixture is studied in the present
investigation. Steel fibers of 1% and polypropylene fibers 0.036% were added individually to the concrete mixture as mono fibers and
then they were added together to form a hybrid fiber reinforced concrete. Mechanical properties such as compressive, split tensile and
flexural strength were determined. The results show that hybrid fibers improve the compressive strength marginally as compared to
mono fibers. Whereas, hybridization improves split tensile strength and flexural strength noticeably.
Keywords:-Hybridization, mono fibers, steel fiber, polypropylene fiber, Improvement in mechanical properties.
Material management in construction – a case studyeSAT Journals
Abstract
The objective of the present study is to understand about all the problems occurring in the company because of improper application
of material management. In construction project operation, often there is a project cost variance in terms of the material, equipments,
manpower, subcontractor, overhead cost, and general condition. Material is the main component in construction projects. Therefore,
if the material management is not properly managed it will create a project cost variance. Project cost can be controlled by taking
corrective actions towards the cost variance. Therefore a methodology is used to diagnose and evaluate the procurement process
involved in material management and launch a continuous improvement was developed and applied. A thorough study was carried
out along with study of cases, surveys and interviews to professionals involved in this area. As a result, a methodology for diagnosis
and improvement was proposed and tested in selected projects. The results obtained show that the main problem of procurement is
related to schedule delays and lack of specified quality for the project. To prevent this situation it is often necessary to dedicate
important resources like money, personnel, time, etc. To monitor and control the process. A great potential for improvement was
detected if state of the art technologies such as, electronic mail, electronic data interchange (EDI), and analysis were applied to the
procurement process. These helped to eliminate the root causes for many types of problems that were detected.
Managing drought short term strategies in semi arid regions a case studyeSAT Journals
Abstract
Drought management needs multidisciplinary action. Interdisciplinary efforts among the experts in various fields of the droughts
prone areas are helpful to achieve tangible and permanent solution for this recurring problem. The Gulbarga district having the total
area around 16, 240 sq.km, and accounts 8.45 per cent of the Karnataka state area. The district has been situated with latitude 17º 19'
60" North and longitude of 76 º 49' 60" east. The district is situated entirely on the Deccan plateau positioned at a height of 300 to
750 m above MSL. Sub-tropical, semi-arid type is one among the drought prone districts of Karnataka State. The drought
management is very important for a district like Gulbarga. In this paper various short term strategies are discussed to mitigate the
drought condition in the district.
Keywords: Drought, South-West monsoon, Semi-Arid, Rainfall, Strategies etc.
Life cycle cost analysis of overlay for an urban road in bangaloreeSAT Journals
Abstract
Pavements are subjected to severe condition of stresses and weathering effects from the day they are constructed and opened to traffic
mainly due to its fatigue behavior and environmental effects. Therefore, pavement rehabilitation is one of the most important
components of entire road systems. This paper highlights the design of concrete pavement with added mono fibers like polypropylene,
steel and hybrid fibres for a widened portion of existing concrete pavement and various overlay alternatives for an existing
bituminous pavement in an urban road in Bangalore. Along with this, Life cycle cost analyses at these sections are done by Net
Present Value (NPV) method to identify the most feasible option. The results show that though the initial cost of construction of
concrete overlay is high, over a period of time it prove to be better than the bituminous overlay considering the whole life cycle cost.
The economic analysis also indicates that, out of the three fibre options, hybrid reinforced concrete would be economical without
compromising the performance of the pavement.
Keywords: - Fatigue, Life cycle cost analysis, Net Present Value method, Overlay, Rehabilitation
Laboratory studies of dense bituminous mixes ii with reclaimed asphalt materialseSAT Journals
Abstract
The issue of growing demand on our nation’s roadways over that past couple of decades, decreasing budgetary funds, and the need to
provide a safe, efficient, and cost effective roadway system has led to a dramatic increase in the need to rehabilitate our existing
pavements and the issue of building sustainable road infrastructure in India. With these emergency of the mentioned needs and this
are today’s burning issue and has become the purpose of the study.
In the present study, the samples of existing bituminous layer materials were collected from NH-48(Devahalli to Hassan) site.The
mixtures were designed by Marshall Method as per Asphalt institute (MS-II) at 20% and 30% Reclaimed Asphalt Pavement (RAP).
RAP material was blended with virgin aggregate such that all specimens tested for the, Dense Bituminous Macadam-II (DBM-II)
gradation as per Ministry of Roads, Transport, and Highways (MoRT&H) and cost analysis were carried out to know the economics.
Laboratory results and analysis showed the use of recycled materials showed significant variability in Marshall Stability, and the
variability increased with the increase in RAP content. The saving can be realized from utilization of recycled materials as per the
methodology, the reduction in the total cost is 19%, 30%, comparing with the virgin mixes.
Keywords: Reclaimed Asphalt Pavement, Marshall Stability, MS-II, Dense Bituminous Macadam-II
Laboratory investigation of expansive soil stabilized with natural inorganic ...eSAT Journals
This document summarizes a study on stabilizing expansive black cotton soil with the natural inorganic stabilizer RBI-81. Laboratory tests were conducted to evaluate the effect of RBI-81 on the soil's engineering properties. The tests showed that with 2% RBI-81 and 28 days of curing, the unconfined compressive strength increased by around 250% and the CBR value improved by approximately 400% compared to the untreated soil. Overall, the study found that RBI-81 effectively improved the strength properties of the black cotton soil and its suitability as a soil stabilizer was supported.
Influence of reinforcement on the behavior of hollow concrete block masonry p...eSAT Journals
Abstract
Reinforced masonry was developed to exploit the strength potential of masonry and to solve its lack of tensile strength. Experimental
and analytical studies have been carried out to investigate the effect of reinforcement on the behavior of hollow concrete block
masonry prisms under compression and to predict ultimate failure compressive strength. In the numerical program, three dimensional
non-linear finite elements (FE) model based on the micro-modeling approach is developed for both unreinforced and reinforced
masonry prisms using ANSYS (14.5). The proposed FE model uses multi-linear stress-strain relationships to model the non-linear
behavior of hollow concrete block, mortar, and grout. Willam-Warnke’s five parameter failure theory has been adopted to model the
failure of masonry materials. The comparison of the numerical and experimental results indicates that the FE models can successfully
capture the highly nonlinear behavior of the physical specimens and accurately predict their strength and failure mechanisms.
Keywords: Structural masonry, Hollow concrete block prism, grout, Compression failure, Finite element method,
Numerical modeling.
Influence of compaction energy on soil stabilized with chemical stabilizereSAT Journals
This document summarizes a study on the influence of compaction energy on soil stabilized with a chemical stabilizer. Laboratory tests were conducted on locally available loamy soil treated with a patented polymer liquid stabilizer and compacted at four different energy levels. The study found that increasing the compaction effort increased the density of both untreated and treated soil, but the rate of increase was lower for stabilized soil. Treating the soil with the stabilizer improved its unconfined compressive strength and resilient modulus, and reduced accumulated plastic strain, with these properties further improved by higher compaction efforts. The stabilized soil exhibited strength and performance benefits compared to the untreated soil.
Geographical information system (gis) for water resources managementeSAT Journals
This document describes a hydrological framework developed in the form of a Hydrologic Information System (HIS) to meet the information needs of various government departments related to water management in a state. The HIS consists of a hydrological database coupled with tools for collecting and analyzing spatial and non-spatial water resources data. It also incorporates a hydrological model to indirectly assess water balance components over space and time. A web-based GIS portal was created to allow users to access and visualize the hydrological data, as well as outputs from the SWAT hydrological model. The framework is intended to facilitate integrated water resources planning and management across different administrative levels.
Forest type mapping of bidar forest division, karnataka using geoinformatics ...eSAT Journals
Abstract
The study demonstrate the potentiality of satellite remote sensing technique for the generation of baseline information on forest types
including tree plantation details in Bidar forest division, Karnataka covering an area of 5814.60Sq.Kms. The Total Area of Bidar
forest division is 5814Sq.Kms analysis of the satellite data in the study area reveals that about 84% of the total area is Covered by
crop land, 1.778% of the area is covered by dry deciduous forest, 1.38 % of mixed plantation, which is very threatening to the
environmental stability of the forest, future plantation site has been mapped. With the use of latest Geo-informatics technology proper
and exact condition of the trees can be observed and necessary precautions can be taken for future plantation works in an appropriate
manner
Keywords:-RS, GIS, GPS, Forest Type, Tree Plantation
Factors influencing compressive strength of geopolymer concreteeSAT Journals
Abstract
To study effects of several factors on the properties of fly ash based geopolymer concrete on the compressive strength and also the
cost comparison with the normal concrete. The test variables were molarities of sodium hydroxide(NaOH) 8M,14M and 16M, ratio of
NaOH to sodium silicate (Na2SiO3) 1, 1.5, 2 and 2.5, alkaline liquid to fly ash ratio 0.35 and 0.40 and replacement of water in
Na2SiO3 solution by 10%, 20% and 30% were used in the present study. The test results indicated that the highest compressive
strength 54 MPa was observed for 16M of NaOH, ratio of NaOH to Na2SiO3 2.5 and alkaline liquid to fly ash ratio of 0.35. Lowest
compressive strength of 27 MPa was observed for 8M of NaOH, ratio of NaOH to Na2SiO3 is 1 and alkaline liquid to fly ash ratio of
0.40. Alkaline liquid to fly ash ratio of 0.35, water replacement of 10% and 30% for 8 and 16 molarity of NaOH and has resulted in
compressive strength of 36 MPa and 20 MPa respectively. Superplasticiser dosage of 2 % by weight of fly ash has given higher
strength in all cases.
Keywords: compressive strength, alkaline liquid, fly ash
Experimental investigation on circular hollow steel columns in filled with li...eSAT Journals
Abstract
Composite Circular hollow Steel tubes with and without GFRP infill for three different grades of Light weight concrete are tested for
ultimate load capacity and axial shortening , under Cyclic loading. Steel tubes are compared for different lengths, cross sections and
thickness. Specimens were tested separately after adopting Taguchi’s L9 (Latin Squares) Orthogonal array in order to save the initial
experimental cost on number of specimens and experimental duration. Analysis was carried out using ANN (Artificial Neural
Network) technique with the assistance of Mini Tab- a statistical soft tool. Comparison for predicted, experimental & ANN output is
obtained from linear regression plots. From this research study, it can be concluded that *Cross sectional area of steel tube has most
significant effect on ultimate load carrying capacity, *as length of steel tube increased- load carrying capacity decreased & *ANN
modeling predicted acceptable results. Thus ANN tool can be utilized for predicting ultimate load carrying capacity for composite
columns.
Keywords: Light weight concrete, GFRP, Artificial Neural Network, Linear Regression, Back propagation, orthogonal
Array, Latin Squares
Experimental behavior of circular hsscfrc filled steel tubular columns under ...eSAT Journals
This document summarizes an experimental study that tested circular concrete-filled steel tube columns with varying parameters. 45 specimens were tested with different fiber percentages (0-2%), tube diameter-to-wall-thickness ratios (D/t from 15-25), and length-to-diameter (L/d) ratios (from 2.97-7.04). The results found that columns filled with fiber-reinforced concrete exhibited higher stiffness, equal ductility, and enhanced energy absorption compared to those filled with plain concrete. The load carrying capacity increased with fiber content up to 1.5% but not at 2.0%. The analytical predictions of failure load closely matched the experimental values.
Evaluation of punching shear in flat slabseSAT Journals
Abstract
Flat-slab construction has been widely used in construction today because of many advantages that it offers. The basic philosophy in
the design of flat slab is to consider only gravity forces; this method ignores the effect of punching shear due to unbalanced moments
at the slab column junction which is critical. An attempt has been made to generate generalized design sheets which accounts both
punching shear due to gravity loads and unbalanced moments for cases (a) interior column; (b) edge column (bending perpendicular
to shorter edge); (c) edge column (bending parallel to shorter edge); (d) corner column. These design sheets are prepared as per
codal provisions of IS 456-2000. These design sheets will be helpful in calculating the shear reinforcement to be provided at the
critical section which is ignored in many design offices. Apart from its usefulness in evaluating punching shear and the necessary
shear reinforcement, the design sheets developed will enable the designer to fix the depth of flat slab during the initial phase of the
design.
Keywords: Flat slabs, punching shear, unbalanced moment.
Evaluation of performance of intake tower dam for recent earthquake in indiaeSAT Journals
Abstract
Intake towers are typically tall, hollow, reinforced concrete structures and form entrance to reservoir outlet works. A parametric
study on dynamic behavior of circular cylindrical towers can be carried out to study the effect of depth of submergence, wall thickness
and slenderness ratio, and also effect on tower considering dynamic analysis for time history function of different soil condition and
by Goyal and Chopra accounting interaction effects of added hydrodynamic mass of surrounding and inside water in intake tower of
dam
Key words: Hydrodynamic mass, Depth of submergence, Reservoir, Time history analysis,
Evaluation of operational efficiency of urban road network using travel time ...eSAT Journals
This document evaluates the operational efficiency of an urban road network in Tiruchirappalli, India using travel time reliability measures. Traffic volume and travel times were collected using video data from 8-10 AM on various roads. Average travel times, 95th percentile travel times, and buffer time indexes were calculated to assess reliability. Non-motorized vehicles were found to most impact reliability on one road. A relationship between buffer time index and traffic volume was developed. Finally, a travel time model was created and validated based on length, speed, and volume.
Estimation of surface runoff in nallur amanikere watershed using scs cn methodeSAT Journals
Abstract
The development of watershed aims at productive utilization of all the available natural resources in the entire area extending from
ridge line to stream outlet. The per capita availability of land for cultivation has been decreasing over the years. Therefore, water and
the related land resources must be developed, utilized and managed in an integrated and comprehensive manner. Remote sensing and
GIS techniques are being increasingly used for planning, management and development of natural resources. The study area, Nallur
Amanikere watershed geographically lies between 110 38’ and 110 52’ N latitude and 760 30’ and 760 50’ E longitude with an area of
415.68 Sq. km. The thematic layers such as land use/land cover and soil maps were derived from remotely sensed data and overlayed
through ArcGIS software to assign the curve number on polygon wise. The daily rainfall data of six rain gauge stations in and around
the watershed (2001-2011) was used to estimate the daily runoff from the watershed using Soil Conservation Service - Curve Number
(SCS-CN) method. The runoff estimated from the SCS-CN model was then used to know the variation of runoff potential with different
land use/land cover and with different soil conditions.
Keywords: Watershed, Nallur watershed, Surface runoff, Rainfall-Runoff, SCS-CN, Remote Sensing, GIS.
Estimation of morphometric parameters and runoff using rs & gis techniqueseSAT Journals
This document summarizes a study that used remote sensing and GIS techniques to estimate morphometric parameters and runoff for the Yagachi catchment area in India over a 10-year period. Morphometric analysis was conducted to understand the hydrological response at the micro-watershed level. Daily runoff was estimated using the SCS curve number model. The results showed a positive correlation between rainfall and runoff. Land use/land cover changes between 2001-2010 were found to impact estimated runoff amounts. Remote sensing approaches provided an effective means to model runoff for this large, ungauged area.
Effect of variation of plastic hinge length on the results of non linear anal...eSAT Journals
Abstract The nonlinear Static procedure also well known as pushover analysis is method where in monotonically increasing loads are applied to the structure till the structure is unable to resist any further load. It is a popular tool for seismic performance evaluation of existing and new structures. In literature lot of research has been carried out on conventional pushover analysis and after knowing deficiency efforts have been made to improve it. But actual test results to verify the analytically obtained pushover results are rarely available. It has been found that some amount of variation is always expected to exist in seismic demand prediction of pushover analysis. Initial study is carried out by considering user defined hinge properties and default hinge length. Attempt is being made to assess the variation of pushover analysis results by considering user defined hinge properties and various hinge length formulations available in literature and results compared with experimentally obtained results based on test carried out on a G+2 storied RCC framed structure. For the present study two geometric models viz bare frame and rigid frame model is considered and it is found that the results of pushover analysis are very sensitive to geometric model and hinge length adopted. Keywords: Pushover analysis, Base shear, Displacement, hinge length, moment curvature analysis
Effect of use of recycled materials on indirect tensile strength of asphalt c...eSAT Journals
Abstract
Depletion of natural resources and aggregate quarries for the road construction is a serious problem to procure materials. Hence
recycling or reuse of material is beneficial. On emphasizing development in sustainable construction in the present era, recycling of
asphalt pavements is one of the effective and proven rehabilitation processes. For the laboratory investigations reclaimed asphalt
pavement (RAP) from NH-4 and crumb rubber modified binder (CRMB-55) was used. Foundry waste was used as a replacement to
conventional filler. Laboratory tests were conducted on asphalt concrete mixes with 30, 40, 50, and 60 percent replacement with RAP.
These test results were compared with conventional mixes and asphalt concrete mixes with complete binder extracted RAP
aggregates. Mix design was carried out by Marshall Method. The Marshall Tests indicated highest stability values for asphalt
concrete (AC) mixes with 60% RAP. The optimum binder content (OBC) decreased with increased in RAP in AC mixes. The Indirect
Tensile Strength (ITS) for AC mixes with RAP also was found to be higher when compared to conventional AC mixes at 300C.
Keywords: Reclaimed asphalt pavement, Foundry waste, Recycling, Marshall Stability, Indirect tensile strength.
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Climate change's impact on the planet forced the United Nations and governments to promote green energies and electric transportation. The deployments of photovoltaic (PV) and electric vehicle (EV) systems gained stronger momentum due to their numerous advantages over fossil fuel types. The advantages go beyond sustainability to reach financial support and stability. The work in this paper introduces the hybrid system between PV and EV to support industrial and commercial plants. This paper covers the theoretical framework of the proposed hybrid system including the required equation to complete the cost analysis when PV and EV are present. In addition, the proposed design diagram which sets the priorities and requirements of the system is presented. The proposed approach allows setup to advance their power stability, especially during power outages. The presented information supports researchers and plant owners to complete the necessary analysis while promoting the deployment of clean energy. The result of a case study that represents a dairy milk farmer supports the theoretical works and highlights its advanced benefits to existing plants. The short return on investment of the proposed approach supports the paper's novelty approach for the sustainable electrical system. In addition, the proposed system allows for an isolated power setup without the need for a transmission line which enhances the safety of the electrical network
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Analytical study and implementation of digital excitation system for diesel generators
1. IJRET: International Journal of Research in Engineering and Technology ISSN: 2319-1163
__________________________________________________________________________________________
Volume: 02 Issue: 05 | May-2013, Available @ http://www.ijret.org 769
ANALYTICAL STUDY AND IMPLEMENTATION OF DIGITAL
EXCITATION SYSTEM FOR DIESEL GENERATORS
Sreehari S1
, Deepak C R2
1
Student, Electrical and Electronics Department, 2
Student, Computer Science Department,
Amrita Vishwa Vidyapeetham, Tamil Nadu, India, sreeharicybex@gmail.com, deepakcrk@gmail.com
Abstract
This paper aims at the study of DIGITAL EXCITATION SYSTEM [Micro Controller based automatic voltage regulator] employed for
synchronous generators .The main component of the digital excitation system is the Automatic Voltage Regulator. This maintains the
machine terminal voltage in desired reference, which can be varied in order to accomplish different power system requirements .The
digital excitation system is developed from the digital signal processor whichwill capture of variables, performs mathematical
operations and control algorithms and sends the control signals to the actuator. Automatic Voltage regulator (automatic/manual
control), over excitation limiter, Under excitation limité and volts/hertz limiter are included in this digital excitation system. The
exciter is controlled three phase SCR’s bridge
Index Terms: DIGITAL EXCITATION SYSTEM, Automatic Voltage Regulator, SCR Bridge, synchronous
generator,dsPIC30F4012.
-----------------------------------------------------------------------***-----------------------------------------------------------------------
1.INTRODUCTION
Microcontroller based automatic voltage regulator is used to
maintain the terminal voltage of the alternator constant from
no load to full load irrespective of power factor and frequency.
As the terminal voltage decreases depending on machine
reactance and load power factor. A suitable excitation control
is required to keep Alternator terminal voltage
constant.Industrial loads are always fluctuating and controlling
the excitation is difficult by manual operation. So suitable
automatic voltage regulator is required to change excitation at
a faster rate against quick changing loads.
Digital Excitation system panel senses the alternator terminals
voltage, varies the power fed to the alternator field to keep
terminal voltage constant irrespective of load conditions. This
is achieved by thyristor controlled rectifier where triggering
phase angle of the thyristor is varied by fast acting highly
sensitive solid state control circuit which works on close loop
principle.
The field of the alternator is fed from AC exciter and rotating
rectifier. The AC exciter field is controlled from AVR panel.
The AVR panel is having auto and manual channel. They
have separate control circuit, whereas power circuit is
common, hence when auto channel is workingit can be
transformed to manual channel without disturbing the load.
The manual channel is controlled by follow up circuit while
system is operating in auto channel.The follow up unit sense
the output reference of auto channel and gives signal to Digital
Reference Unit (DRU) of the manual channel to maintain the
same reference of auto channel.The power circuit consists of
half controlled full wave thyristor rectifier bridge. The
dsPIC30F4012 will control the firing angle of the thyristors
which control the power fed to the field, overexcited as well as
the under excited condition of the generator by adjusting the
firing angle. So, the software embedded in the microcontroller
helps to maintain fixed terminal voltage, logical operations of
the generator, protection of generator and to maintain the
constant power factor by adjusting the firing angle of the
thyristors.
2. SYNCHRONOUS GENERATOR
2.1 PRINCIPLE OF OPERATION
A synchronous generator is universally employed for the
generation of three phase power at all generating stations. The
largest–sized electrical machines are polyphase synchronous
generators. Under steady-state conditions, the operating speed
of a synchronous machine depends on the frequency
ofarmature currents and the number of field poles and is given
by
Where,
P= number of field poles
N= rotor speed in rpm (Synchronous speed)
F=frequency of armature currents.
120
NP
F
2. IJRET: International Journal of Research in Engineering and Technology ISSN: 2319-1163
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Volume: 02 Issue: 05 | May-2013, Available @ http://www.ijret.org 770
Fig.1. Synchronous machine construction and three phase
voltage generated at the terminals of generator
For the successful operation, the rotational speed of the
synchronous machine must synchronize with the frequency of
the energy system that meansthe stator flux and rotor flux
should get tightly bounded and the value of slip should be
zero. For production of torque the relative velocity between
the interacting stator and rotor fields must be zero.
When a synchronous generator is excited with field current
and driven at constant speed, balanced voltage is generated
in the armature winding. If balanced load is connected across
armature winding, balanced armature current at the same
frequency as the e.m.f will flow. Since the frequency of
generated e.m.f is related to the rotor speed, while the speed of
the armature rotating m.m.f is related to the frequency of the
current, it follows that the armature m.m.f rotates
synchronously with the rotor field. An increase in rotor speed
results in a rise in the frequency of e.m.f and current, while the
power factor is determined by the nature of the load.
Fig.2a. Equivalent circuit and phasor diagram for R load
Since the armature mmf rotates at the same speed as the main
field, it produces a corresponding e.m.f in the armature
winding. The effects of armature reaction and armature
winding leakage are considered to produce an equivalent
internal voltage drop across the synchronous reactance Xs,
while the field excitation is accounted for by the open-circuit
armature voltage Ef. The impedance Zs= (R+jXs) is known as
the synchronous impedance of the synchronous generator,
where R is the armature resistance.
For steady-state performance analysis, the per-phase
equivalent circuit shown in Figure 2 is used.
The synchronous generator, under the assumption of constant
synchronous reactance, may be considered as represent able
by an equivalent circuit comprising an ideal
3. IJRET: International Journal of Research in Engineering and Technology ISSN: 2319-1163
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Volume: 02 Issue: 05 | May-2013, Available @ http://www.ijret.org 771
Fig.2b. Equivalent circuit and phasor diagram for R-L load
Winding in which an e.m.f. Et proportional to the field
excitation is developed, the winding being connected to the
terminals of the machine through a resistance ra and reactance
(Xl + Xa ) = Xs all per phase. This is shown in Fig.2. The
principal characteristics of the synchronous generator will be
obtained qualitatively from this circuit [1, 3, 6].
2.2 GENERATOR LOAD CHARACTERISTICS
On open circuit the terminal voltage V is the same as the open
circuit e.m.f. Et .Suppose a unity-power-factor load be
connected to the machine. The flow of load current produces a
voltage drop IZs in the synchronous impedance and terminal
voltage V is reduced. The terminal voltage is obtained from
the complex summation
t SV E IZ
Fig.2c. Generator load characteristics
Algebraically this can be written
2 2 2
( )t s rV E I X I
for non-reactive loads. Since normally r is small
compared with Xs
2 2 2 2
.s tV I X E const
so that the V/I curve is as given below[6].
2.3GENERATOR EXCITATION FOR CONSTANT
VOLTAGE
Since the e.m.f. Et is proportional to the excitation when the
synchronous reactance is constant, the Eqn.
2 2 2
( cos ) ( s )tE V Ir V in IXs
can be applied directly to obtain the excitation necessary to
maintain constant output voltage for all loads. All unity-and
lagging power-factor loads will require an increase of
excitation with increase of load current, as a corollary of Fig.3.
Low-leading-power-factor loads, on the other hand, will
require the excitation to be reduced on account of the direct
magnetizing effect of the zero- power-factor component.
Fig.3. Generator excitation for constant voltage
The voltage-regulation of a synchronous generator is the
voltage rise at the terminals when a given load is thrown off,
the excitation and speed remaining constant.The voltage-rise
is clearly the numerical difference between Et and V, where V
is the terminal voltage for a given load and Et is the open-
circuit voltage for the same field excitation.Expressed as a
fraction, the regulation is[6]
( )tE V
perunit
V
3. PROPOSED SCHEME:MICROCONTROLLER
BASED AUTOMATIC VOLTAGE REGULATOR
As the automatic voltage regulator (AVR), which regulates
generator voltage, is a device indispensable for operation, it is
required to have superior reliability in addition to easy
maintenance or repair features. And, recently there exists an
ever-increasing demand for improved system stability through
the excitation control (AVR) in order to prevent decline in
system stability in line with the increase in power system and
power re-routing. At the same time, digital devices as
represented by micro-controllers have been making a
remarkable progress. The digital excitation systems are
achieving, high reliability, easy-operation, and easy
4. IJRET: International Journal of Research in Engineering and Technology ISSN: 2319-1163
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Volume: 02 Issue: 05 | May-2013, Available @ http://www.ijret.org 772
maintainability plus improved space factor. The main
components of the digital excitation system include:
a] A.C.EXCITATION UNIT
b] ROTATING DIODE or ROTATING RECTIFIER
c] MAIN SYNCHRONOUS GENERATOR
d] MICROCONTROLLER UNIT [dsPIC30F4012]
e] 3-PHASE FULLY BRIDGED THYRISTOR BRIDE
f] ZEROCROSSING DETECTOR
The digital automatic voltage regulator is needed to control the
voltage and the reactive power of the generator. The main
tasks of the regulator are to control the voltage in the steady
state, regulate the voltage under fault conditions and to
facilitate reactive power load-sharing between generators in
parallel operation. The voltage control is used in generators in
island mode operation or in parallel operation with weak
networks. Power factor is controlled in case the generator is
operating in parallel with a strong network. In case of voltage
control, the reactive power sharing between generators can be
controlled additionally by using a reactive droop
compensation method in which the voltage is lowered in the
generator from which the reactive current flows. This lowers
the need for excitation and thus also the reactive current. The
simplest analog automatic voltage-regulator solutions only
control the excitation current in load operation. In more
complex digital regulators, the control functions usually
include power factor control, generator soft start capability,
over-voltage and under-frequency protection, under- and over
excitation current limitation and voltage matching before
synchronizing. The D-AVR supplies and controls the current
in the field winding of the exciter to provide the needed
excitation current to the field winding in the rotor. The
excitation is controlled typically by means of a PID control
algorithm and a diode-bridge rectifier fed switch-mode power
supply or a thyristor-bridge rectifier. The diode bridge rectifier
is a line-commutated converter in which the firing of the
diodes depends only on the line voltage. The Thyristor Bridge
is a self-commutated converter, and the thyristors must be
fired to conduct the current. Typically, Digital automatic
voltage regulators can be supplied by either single or three
phase AC voltage or DC voltage. However, the excitation
current output from the regulator may be limited to a value
lower than the rated value when supplied with single-phase
voltage. A higher current can be achieved with a single-phase
supply by installing an external rectifier and a capacitor on the
D-AVR mounting plate. In no-load operation, the D-AVR
must provide a sufficient field current for the Generator to
produce the rated voltage at the rated speed. From no-load to
full-load operation, the excitation current must be increased to
compensate the effects of the armature reaction. In a generator
short circuit, the D-AVR cannot limit the excitation current
and all the power fed to the AVR is used in excitation. Thus
the excitation current must be limited by other means in order
to reduce the generator short-circuit current. This can be done
by using a separate excitation current limiter. Voltage and
current transformers are needed to measure the instantaneous
values of the main voltage and current to enable the voltage
regulation. As the load current increases, the armature reaction
reduces the air-gap flux and a voltage drop occurs in the
terminals of the generator. The AVR must increase the
excitation current to compensate the armature reaction and the
voltage drops caused by the reactance’s of the machine. The
microcontroller based automatic voltage regulator. In
Microcontroller based Automatic Voltage Regulating system
the terminal voltage from the synchronous generator is fed to
the dsPIC[8]. The dsPIC30F family of devices includes
peripherals that are ideally suited for power control
applications. These peripherals include a high-resolution
PWM module, a 10-bit 2 Msps Analog-to-Digital Converter
module and an Analog Comparator module. The software
embedded in the dsPIC calculates the firing angle and fires the
thyristor bridge in such a way to maintain the terminal voltage
to a referred value. On calculating the firing angle over
excitation limit, under excitation limit, power factor and
synchronized operation of the generator has to be maintained.
Terminal voltage and current is fed to the dsPIC with the help
of PT and CT and the power factor is also fed to the IC with
the help of the timing circuit. Terminal voltage is stepped
down in the range of 0-5v and fed to the IC with the help of
zero crossing detectors [2,4,5,7].
3.1 SYNCHRONISED WORKING OF
GENERATOR
While generator running in parallel with grid the excitation
has to be properly matching may lead to undesirable reactive
loads which may overload alternator an utility factor become
very poor. In case of alternator operating with grid, it has to
run at a constant power factor to meet EB requirement. And
also to maintain the ratio of active and reactive power
irrespective of grid voltage variation to get optimum
utilization. The power factor controller sense the power factor
of the alternator, compare with the reference set and correct
excitation through digital reference unit [DRU].To avoid
oscillation in correction, a dead band setting pot is also given
to adjust the dead band, depending on the fluctuation of the
bus voltage. Two pots are provided to adjust on time of the
rise pulse and on time of lower pulse. Power Factor control by
using separate power factor controller unit which corrects the
excitation parameters through Digital Reference Unit while
operating parallel with grid .Follow up unit is provided to
follow the auto channel and gives corrective signals to the
manual channel. During external fault conditions automatic
change over from auto to manual takes place without
disturbing the load conditions. After rectification of the fault,
change over from manual to auto is possible. That is to change
from manual to auto without disturbing the load conditions;
manually we have to set the reference of auto channel equal to
the manual channel[9].
5. IJRET: International Journal of Research in Engineering and Technology ISSN: 2319-1163
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Volume: 02 Issue: 05 | May-2013, Available @ http://www.ijret.org 773
3.2 UNDER/OVEREXCITED CONDITION OF
SYNCHRONOUS GENERATOR
During generator operation, it is necessary to observe the
permissible combinations of active and reactive power, which
can be seen from the capability diagram. Limiters employed in
the digital excitation system limits the dangerous operation of
the generators, which can cause damages as overheating, over
fluxing and loss of synchronism. The limiters take the
operating point to a state inside of the limits of machine’s
capability. Limiters can be over excitation limiter, under
excitation limiter, overvoltage limiter, over current limiter,
voltage/frequency limiter although they can include some
others for example the power factor limiter and reactive power
limiter. For this application the over excitation limiter, under
excitation limiter and V/Hz limiter were developed in the
DSP.The under excitation limiter corrects the reactive power
by raising the machine voltage as necessary to ensure that, in
case of an excursion beyond the limit characteristic, the
operating point is returned to that characteristic before the
machine is tripped by the under excitation protection.
The over excitation limiter ensures that, in the overexcited
range, the operating point always keeps within capability
curve section of the generator. In response to system voltage
drops caused by high reactive power requirements, switching
manipulations or faults, the voltage regulator raises the
excitation level so as to keep the generator voltage constant.
The over excitation limiting device acts as a safeguard against
thermal overloading of the rotor.
Fig.4. Possible Design of the Generator Capability Diagram
The over excitation limiter admits excitation current values
between The maximum continuous current and the maximum
excitation Current (field forcing) for a limited period of time
so that the Generator can back up the system in response to
short-time system Voltage dips. The secondary excitation
current limiter (field-forcing limiter), in contrast, has the task
of limiting the excitation current to the maximum permissible
value as quickly as possible. The stator current limiter ensures
the delayed limitation onto working points, within the N-P
range of the generator power diagram. The main task of the
stator current limiter is to prevent the generator stator from
thermical overload, whichcan be caused by a high reactive
power at increased active power.
Fig.5. Possible Design of the Generator stability Diagram
The stator current limiter also permits increased excitation
values for a limited period so that the generator can back up
the system.The over excitation limiter prevents an overheating
in the machine’s field winding. The under excitation limiter
avoids the machine loss of synchronism or avoids an
overheating in the stator end region. The volt/Hertz limiter
receives the terminal voltage and its frequency as input
signals, and protects the synchronous machine and
transformers connected to it damages by conditions of over
flux. The over flux is caused due to a big relation between
voltage and frequency, caused for a suddenly frequency drop.
The control of the power factor is also important for the
stabilized working of generator.While generator running in
parallel with grid or with other alternators the excitation has to
be properly matched. Improper matching may lead to
undesirable reactive loads which may overload the generator
and utility factor becomes very poor. If the power factor is
properly balanced to load power factor for alternator running
in parallel the utilization of alternator is maximum. In case of
alternator operating with grid, it has to run at constant power
factor to meet EB requirement of maintaining the ratio of
active and reactive power irrespective of grid voltage to get
optimum utilization. The timing unit senses the angle between
voltage vector and current vector and this angle is fed to the
dsPIC as interrupts.[10]
6. IJRET: International Journal of Research in Engineering and Technology ISSN: 2319-1163
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Volume: 02 Issue: 05 | May-2013, Available @ http://www.ijret.org 774
4. FLOWCHART
MAIN
INITIALISE TEMPORARY REGISTERS
INITIALISE PORT B, C, D, E
INITILISE TIMER 1,
2, 3
LOAD FIRING
ANGLE
INITIALISE ADC
REGISTER
INITIALISE ADC RESULT
REGISTER FROM LOWEST
HARDWARE
INTERRUPT
TIMER
2
A
ENABLE RISE INT FOR INT FIRST
POSITION
VOLTAGE FEEDBACK ADC
CURRENT REFERENCE ADC
CURRENT FEEDBACK ADC
VOLTAGE REFERENCE ADC
A
YES
YES
NO
YES
CHECK THE
HIGHER LIMIT
[WITH IN
THEPRESCRIBED
LIMIT] .
NO
INCREMENT THE VALUE
OF FIRING ANGLE
NO
DECREMENT THE VALUE
OF FIRING ANGLE
CHECK
THE
LIMIT=ZER
O .
CHECK THE
LOWER
LIMIT [WITH
IN
THEPRESCRI
BED LIMIT]
.
NEGG
VOLTAG
E REF
-
VOLTAG
E FEED.
POS/0
B
Mai
n
DECREMENT THE
VALUE OF FIRING
ANGLE
CURRENT
REF.
-
CURRENT
FEED.
CHECK THE
LOWER
LIMIT
[WITH IN
THEPRESCRI
BED LIMIT]
.
NEG
NO
POS/0
YES
B
7. IJRET: International Journal of Research in Engineering and Technology ISSN: 2319-1163
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Volume: 02 Issue: 05 | May-2013, Available @ http://www.ijret.org 775
5. COMPLETE BLOCK DIAGRAM
8. IJRET: International Journal of Research in Engineering and Technology ISSN: 2319-1163
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Volume: 02 Issue: 05 | May-2013, Available @ http://www.ijret.org 776
CONCLUSIONS
The digital excitation system developed by DSPIC. The
structure utilized for the task execution allowed a good
performance of the system dynamics.
Manual and auto control functions using proportional action
and proportional integral action were enough for obtaining fast
response speed and a zero state stationary error. The over
excitation limiter implemented using a first order dynamics
permits that the limiter operates faster when previous over
excitation levels are high; on the other hand the hysteresis
zone avoids oscillations around the limit point when the
limiter is given back to zero.
The under excitation limiter presets a good performance,
however oscillations around the operation limit zone were
observed, because its structure moved the generator operation
point to the limit line. The operation of the v/hz limiter was
adequate; when is presented a relation between
voltage/frequency on top of 1.05 pu decreased the voltage in
the same proportion that the frequency drops, avoiding an
excessive overflux. Future implementations require to reject
the oscillations presented on the under excitation limiter and
the overshoots in the voltage/frequency limiter. Thus by
employing under excitation as well as over excitation limiters
an efficient and a balanced calculation of the firing angle can
be obtained from the DSPIC 30F 4012nd fed to the thyristor
bridge.
REFERENCES
[1]JB Gupta, “Theory and performance of Electrical
Machines”, S.K. Kataria and Sons publishers, Fourteen
Edition.
[2]Dr. P. S. Bimbra, “Generalized Theory of Electrical
Machines” Khanna publishers, Fifth Edition.
[3]. R.Krishanam, “Electric Motor drives Modelling, analysis
and control”, PHI-India-2009
[4].Orozco, M. L.; Vasquez, H., "Dynamic performance of an
excitation system built in a digital way," Industrial Electronics
and Control Applications, 2005. ICIECA 2005
[5] Juan Dixon (Ph.D.), “three phase controlled rectifiers”,
Department of Electrical EngineeringPontificia Universidad
Católica de ChileVicuña Mackenna 4860 Santiago, CHILE.
[6] Prof. Krishna Vasudevan, Prof. G. SridharaRao,Prof. P.
SasidharaRao” Electrical Machines II”Indian Institute of
Technology Madras.
[7] http://operation of three phase thyristor bridge rectifier
service.eng.uts.edu.
[8]http://microchip.com/dspic30f4012/datasheet.
[9] http://WWW.abb.com/motor&drives.
[10] Dr. Hans-Joachim Herrmann, “Under excitation
Protection”, Power Transmission and Distribution, Siemens,
2007.
BIOGRAPHIES:
Sreehari S received the B.Tech
degree in Electrical & Electronics
Engineering from Calicut
University Institute of Engineering
&Technology, under University of
Calicut Kerala, India, in 2010 and
currently doing M.Tech in Power
Electronics in Amrita
vishwavidyapeetham, Coimbatore,
India. He has published papers in
various international Journals. His research interests
Multilevel inverter structures, renewable energy technologies,
electric drives and control and Excitation systems.
Deepak C R received the B.Tech
degree in computer science from
university of Calicut, Kerala, India, in
2011and currently doing M.Tech in
computer vision and image processing
in Amrita vishwavidyapeetham
university, Coimbatore, India. He has
published papers related to image
processing and electrical engineering
in various international journals. His
research interests include content based video/image retrieval,
document image analysis,digital image watermarking and
computer vision.