This document discusses sensorless vector control of induction motors. It presents the dynamic modeling of induction motors using a reference frame transformation. It then describes the principles of vector control using an inverse transformation to control stator currents. A model reference adaptive system is proposed for sensorless speed estimation, where an adaptive model estimates the rotor speed by comparing its output to a reference model. Simulation results show the sensorless control approach can accurately estimate speed with good tracking performance.
This document summarizes a research paper on sensorless control of induction motors using a model reference adaptive system (MRAS). It begins with an introduction to induction motors and their importance in industry. It then provides the mathematical modeling of induction motors, including the dynamic equations. It describes vector control principles and how a synchronously rotating reference frame is used. Finally, it introduces MRAS as a method for rotor flux estimation for sensorless vector control without directly measuring rotor position. The goal is to develop an induction motor drive with dynamic performance comparable to a sensor-based drive using this sensorless control approach.
This document contains questions from 5 units related to solid state drives. It includes questions about electrical drives and their components, DC and AC motor drives, speed control methods, and specific motor types like induction motors, synchronous motors, and permanent magnet synchronous motors. The questions cover topics like drive system modeling, operating modes, control strategies, and performance analysis.
This document discusses estimating the efficiency of electric machines using magnetic flux circuits. It presents the development of a generalized 4th order dq model equation of an electrical machine expressed in an arbitrary reference frame. The model equations are transformed to use all flux linkage variables instead of current variables. Results using this flux linkage approach are compared to measured machine quantities and good estimations of efficiency are obtained. Magnetic equivalent circuit modeling is an effective method for simulating electric machine performance and estimating efficiency variations in both transient and steady states.
This document discusses brushed DC motors and provides details about their key components and operating principles. It describes how a brushed DC motor works using a stator to generate a magnetic field, a rotor that spins when its windings are energized, and brushes and a commutator that mechanically switch the winding currents. It also outlines the main types of brushed DC motors, including permanent magnet, shunt-wound, series-wound, and compound-wound motors.
This document discusses low voltage circuit breakers and their trip characteristic curves. It defines key terms related to circuit breakers, including molded case circuit breakers (MCCBs), low voltage power circuit breakers (LVPCBs), thermal magnetic and electronic trip units. It describes the different protection functions that trip units can provide, such as overload protection, short circuit protection, and ground fault protection. The document provides examples of time-current curves for thermal magnetic and electronic trip units to illustrate their tripping characteristics under different fault conditions.
This paper investigates a novel dual-rotor permanent magnet synchronous motor (DRPMSM) through modeling and simulation. The model of the DRPMSM is constructed in MATLAB/Simulink. Vector control and space vector PWM control strategies are used to simulate the motor model. The simulation results show the model operates correctly under both control strategies. The responses of torque, speed and current are analyzed and compared under the different control strategies. Key characteristics of the DRPMSM such as the relationship between the speeds of the inner and outer rotors are also analyzed.
This document summarizes research on analyzing and comparing total harmonic distortion (THD) in diode-clamped multilevel Z-source inverters using different pulse width modulation (PWM) control techniques. The study proposes using phase disposition, phase opposition disposition, alternative phase opposition disposition, and phase shifted multicarrier PWM to control a five-level diode-clamped multilevel Z-source inverter. THD reduction performance is evaluated and compared to a conventional three-level diode-clamped inverter. Simulation results show the proposed inverter can significantly reduce harmonic content in output voltages through appropriate multicarrier PWM schemes.
This document summarizes a research paper on sensorless control of induction motors using a model reference adaptive system (MRAS). It begins with an introduction to induction motors and their importance in industry. It then provides the mathematical modeling of induction motors, including the dynamic equations. It describes vector control principles and how a synchronously rotating reference frame is used. Finally, it introduces MRAS as a method for rotor flux estimation for sensorless vector control without directly measuring rotor position. The goal is to develop an induction motor drive with dynamic performance comparable to a sensor-based drive using this sensorless control approach.
This document contains questions from 5 units related to solid state drives. It includes questions about electrical drives and their components, DC and AC motor drives, speed control methods, and specific motor types like induction motors, synchronous motors, and permanent magnet synchronous motors. The questions cover topics like drive system modeling, operating modes, control strategies, and performance analysis.
This document discusses estimating the efficiency of electric machines using magnetic flux circuits. It presents the development of a generalized 4th order dq model equation of an electrical machine expressed in an arbitrary reference frame. The model equations are transformed to use all flux linkage variables instead of current variables. Results using this flux linkage approach are compared to measured machine quantities and good estimations of efficiency are obtained. Magnetic equivalent circuit modeling is an effective method for simulating electric machine performance and estimating efficiency variations in both transient and steady states.
This document discusses brushed DC motors and provides details about their key components and operating principles. It describes how a brushed DC motor works using a stator to generate a magnetic field, a rotor that spins when its windings are energized, and brushes and a commutator that mechanically switch the winding currents. It also outlines the main types of brushed DC motors, including permanent magnet, shunt-wound, series-wound, and compound-wound motors.
This document discusses low voltage circuit breakers and their trip characteristic curves. It defines key terms related to circuit breakers, including molded case circuit breakers (MCCBs), low voltage power circuit breakers (LVPCBs), thermal magnetic and electronic trip units. It describes the different protection functions that trip units can provide, such as overload protection, short circuit protection, and ground fault protection. The document provides examples of time-current curves for thermal magnetic and electronic trip units to illustrate their tripping characteristics under different fault conditions.
This paper investigates a novel dual-rotor permanent magnet synchronous motor (DRPMSM) through modeling and simulation. The model of the DRPMSM is constructed in MATLAB/Simulink. Vector control and space vector PWM control strategies are used to simulate the motor model. The simulation results show the model operates correctly under both control strategies. The responses of torque, speed and current are analyzed and compared under the different control strategies. Key characteristics of the DRPMSM such as the relationship between the speeds of the inner and outer rotors are also analyzed.
This document summarizes research on analyzing and comparing total harmonic distortion (THD) in diode-clamped multilevel Z-source inverters using different pulse width modulation (PWM) control techniques. The study proposes using phase disposition, phase opposition disposition, alternative phase opposition disposition, and phase shifted multicarrier PWM to control a five-level diode-clamped multilevel Z-source inverter. THD reduction performance is evaluated and compared to a conventional three-level diode-clamped inverter. Simulation results show the proposed inverter can significantly reduce harmonic content in output voltages through appropriate multicarrier PWM schemes.
This document describes several methods for estimating the speed of an induction motor, including:
1. A conventional MRAS (Model Reference Adaptive System) method using a reference model and adaptive model to estimate rotor flux linkages and speed.
2. An AI-based MRAS method using a two-layer neural network instead of a mathematical model, which provides more accurate estimation and is more robust to parameter variations.
3. An improved AI-based MRAS method with a dynamic reference model that estimates stator resistance online, making the scheme more independent of machine parameters.
4. A method to control motor speed using the estimated speed in a feedback loop with SVPWM (Space Vector Pulse Width
The document proposes a direct torque control (DTC) method for induction motors that combines space vector modulation (SVM) and an adaptive stator flux observer. It aims to preserve the fast dynamic response of DTC while improving steady-state performance and reducing torque ripple through SVM. An adaptive flux observer is designed using state feedback control theory to ensure stability and robustness. Simulation results validate the effectiveness of the proposed DTC-SVM approach with PI control and an adaptive flux observer in reducing torque ripple compared to conventional DTC.
Consists of two sets of windings:
3 phase armature winding on the stator distributed with centres 120° apart in space
field winding on the rotor supplied by DC
Two basic rotor structures used:
salient or projecting pole structure for hydraulic units (low speed)
round rotor structure for thermal units (high speed)
Salient poles have concentrated field windings; usually also carry damper windings on the pole face.Round rotors have solid steel rotors with distributed windings
Nearly sinusoidal space distribution of flux wave shape obtained by:
distributing stator windings and field windings in many slots (round rotor);
shaping pole faces (salient pole)
This document presents a practical implementation of direct torque control (DTC) for an induction motor drive using a digital signal processor (DSP). It describes the modeling and control system configuration for DTC, including the selection of state variables for flux and torque control. A sliding mode controller is designed for direct flux and torque control. Simulation and experimental results validate the DTC method and show reduced torque pulsations and constant switching frequency, demonstrating high performance of the control system.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
A novel sliding-mode control of induction motor using space vector modulation...ISA Interchange
This document presents a novel sliding-mode control method for torque control of induction motors that integrates sliding-mode control and space vector modulation. The sliding-mode control provides robustness while the space vector modulation improves torque, flux and current performance by reducing ripple. Simulation results show the proposed control scheme provides robust dynamic characteristics with low torque ripple.
Dual inverter fed induction motor drives provide more advantages in contrast with other multilevel inverter drives. Coupled PWM techniques provide good standard of output voltage than the decoupled PWM techniques for dual inverter configuration. In this paper analysis of open end winding induction motor by coupled random PWM signals and decoupled SVPWM signals was carried out. Induction motor by random PWM technique generate low acoustic noise and electromagnetic interference to near by systems. The performance evaluation of the drive wss implemented in MATLAB/simulink and the results were presented.
This document discusses power quality improvement using a 3-phase cascaded H-bridge multilevel inverter under unbalanced voltage conditions. It proposes using a closed loop control system with a PI controller to maintain a constant load voltage under over and under voltage conditions. Sinusoidal pulse width modulation techniques are used to generate triggering pulses for the multilevel inverter. Simulation results using MATLAB validate that this approach can effectively improve power quality by eliminating unbalanced supply voltages and regulating the load voltage.
This document summarizes the simulation of a brushless DC motor (BLDC) fed by two types of multilevel inverters - a five-level diode clamped inverter and a five-level cascaded H-bridge inverter. It first describes the operating principles and switching techniques of the two inverter topologies. It then presents the modeling of the BLDC motor. Simulation results are shown for the firing pulses, line voltages, stator currents, back EMF, speed, torque, etc. of the BLDC motor when powered by each inverter configuration. The performance of the motor fed by the two multilevel inverters is compared.
This document presents a novel particle swarm optimization technique to optimize PID controller parameters for controlling the speed of a linear brushless DC motor. The PSO algorithm is used to determine the optimal proportional, integral and derivative gains for the PID controller. Simulation results show that the proposed PSO-PID controller improves the dynamic performance of the motor system by reducing rise time, overshoot, settling time and steady state error.
This document contains an examination for the course Electrical Machines and Drives held at Universiti Tun Hussein Onn Malaysia. It consists of 6 questions testing knowledge of various electric machines including DC machines, transformers, induction motors, synchronous generators, shaded pole motors and reluctance motors. Students are instructed to answer 4 questions out of the 6 in the 2 hour and 12 minute examination.
This document summarizes a research paper that proposes a novel approach to designing a low power 6T (8x8) SRAM cell using MOS Current Mode Logic (MCML) technique at a 45nm technology node. Simulation results show that an SRAM cell array designed with MCML achieves significant reductions in power dissipation, leakage current, and static power compared to a conventional 6T SRAM cell design. At a supply voltage of 1.2V, the MCML design achieves a power dissipation of 128.6uW versus 480.3uW for the conventional design. The MCML design also exhibits lower leakage current, static power, power-delay product, and energy-delay product. Therefore
New Model Variable Frequency Transformer (NMVFT) – A Technology for V/f Contr...IDES Editor
Variable frequency transformer (VFT) is used as a
controllable bidirectional transmission device that can transfer
power between asynchronous networks and functionally is
similar to back-to-back HVDC. This paper describes the basic
concept of a New Model Variable Frequency Transformer
(NMVFT). NMVFT is a new technology which is used for v/f
control of induction motors. A digital simulation model of
NMVFT and its control system are developed using MATLAB.
The out power thus generated in v/f mode has been practically
verified for the speed control of a three-phase induction motor.
Thus constant speed-torque characteristics were achieved.
The left-hand rule for motors is used to determine the direction of force and motion produced on a current-carrying conductor in a magnetic field.
To use the left-hand rule:
1. Point the thumb of your left hand in the direction of the magnetic field lines.
2. Point your index finger in the direction of the current flowing through the conductor.
3. Your middle finger will now point in the direction of the force on the conductor due to the interaction of the current and magnetic field.
The direction of the force gives the direction of motion of the conductor. This principle is used in DC motors to generate a rotational motion from an electrical current.
Study of Low Voltage Cascode Current Mirror with Enhance Dynamic Rangeijsrd.com
The current mirror is one of most common building blocks both in analog and mixed mode VLSI circuits and the performance of analog structures largely depends on their characteristics. The current mirror can be used as an active element and as a biasing circuit. In this paper we study about the current mirror, cascode current mirror and different low voltage current mirror topology and study the literature survey. After that we study, analysis and design of convention Level shifted low voltage current mirror and TSPICE simulation technology. Presented analysis low voltage current mirror input –output characteristic, high output swing capability and wide input -output swing capabilities, suitable for low voltage operation and minimum power dissipation.
This document analyzes linear switched reluctance motors (LSRM). It begins by describing conventional switched reluctance motors (SRM) and their working principles. It then discusses the construction, working, and advantages of LSRM compared to SRM. Key differences between SRM and LSRM are that LSRM provide linear motion rather than rotational motion and have higher efficiency and power density. The document also covers applications of SRM and concludes by listing topics to be covered in a future review.
This document proposes a novel structure to improve the common mode rejection ratio (CMRR) of circuits like current buffers and folded cascode amplifiers. The proposed structure uses only four transistors and a current source to deviate common mode signals without affecting differential mode signals. This improves the CMRR by at least 12dB while preserving the CMRR bandwidth, which is a novel technique. The structure was applied to both a current buffer and folded cascode amplifier based on simulation results, demonstrating its effectiveness in improving CMRR.
The document discusses DC machines and their components and operation. It covers:
1) The basic principles of electromechanical energy conversion in DC machines including generation of electromotive force through Faraday's law of induction and development of torque when current carrying conductors are placed in a magnetic field.
2) The construction of DC machines including the field system, armature, commutator, and armature windings.
3) Equations for calculating induced emf, terminal voltage, torque, and motor/generator characteristics based on the machine components and operating parameters.
This document summarizes a paper that proposes a new approach to feature-based 3D modeling of turned components in AutoCAD. The approach develops algorithms to model features like cylinders, tapers, holes, and grooves based on user-entered dimensions. It then stores feature information and uses it to assess similarity between components. The modeling system supports both feature-based design and recognition without needing separate feature extraction. The paper presents the algorithms for modeling different features and assessing similarity based on common features like cylinders, holes, or grooves.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document describes several methods for estimating the speed of an induction motor, including:
1. A conventional MRAS (Model Reference Adaptive System) method using a reference model and adaptive model to estimate rotor flux linkages and speed.
2. An AI-based MRAS method using a two-layer neural network instead of a mathematical model, which provides more accurate estimation and is more robust to parameter variations.
3. An improved AI-based MRAS method with a dynamic reference model that estimates stator resistance online, making the scheme more independent of machine parameters.
4. A method to control motor speed using the estimated speed in a feedback loop with SVPWM (Space Vector Pulse Width
The document proposes a direct torque control (DTC) method for induction motors that combines space vector modulation (SVM) and an adaptive stator flux observer. It aims to preserve the fast dynamic response of DTC while improving steady-state performance and reducing torque ripple through SVM. An adaptive flux observer is designed using state feedback control theory to ensure stability and robustness. Simulation results validate the effectiveness of the proposed DTC-SVM approach with PI control and an adaptive flux observer in reducing torque ripple compared to conventional DTC.
Consists of two sets of windings:
3 phase armature winding on the stator distributed with centres 120° apart in space
field winding on the rotor supplied by DC
Two basic rotor structures used:
salient or projecting pole structure for hydraulic units (low speed)
round rotor structure for thermal units (high speed)
Salient poles have concentrated field windings; usually also carry damper windings on the pole face.Round rotors have solid steel rotors with distributed windings
Nearly sinusoidal space distribution of flux wave shape obtained by:
distributing stator windings and field windings in many slots (round rotor);
shaping pole faces (salient pole)
This document presents a practical implementation of direct torque control (DTC) for an induction motor drive using a digital signal processor (DSP). It describes the modeling and control system configuration for DTC, including the selection of state variables for flux and torque control. A sliding mode controller is designed for direct flux and torque control. Simulation and experimental results validate the DTC method and show reduced torque pulsations and constant switching frequency, demonstrating high performance of the control system.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
A novel sliding-mode control of induction motor using space vector modulation...ISA Interchange
This document presents a novel sliding-mode control method for torque control of induction motors that integrates sliding-mode control and space vector modulation. The sliding-mode control provides robustness while the space vector modulation improves torque, flux and current performance by reducing ripple. Simulation results show the proposed control scheme provides robust dynamic characteristics with low torque ripple.
Dual inverter fed induction motor drives provide more advantages in contrast with other multilevel inverter drives. Coupled PWM techniques provide good standard of output voltage than the decoupled PWM techniques for dual inverter configuration. In this paper analysis of open end winding induction motor by coupled random PWM signals and decoupled SVPWM signals was carried out. Induction motor by random PWM technique generate low acoustic noise and electromagnetic interference to near by systems. The performance evaluation of the drive wss implemented in MATLAB/simulink and the results were presented.
This document discusses power quality improvement using a 3-phase cascaded H-bridge multilevel inverter under unbalanced voltage conditions. It proposes using a closed loop control system with a PI controller to maintain a constant load voltage under over and under voltage conditions. Sinusoidal pulse width modulation techniques are used to generate triggering pulses for the multilevel inverter. Simulation results using MATLAB validate that this approach can effectively improve power quality by eliminating unbalanced supply voltages and regulating the load voltage.
This document summarizes the simulation of a brushless DC motor (BLDC) fed by two types of multilevel inverters - a five-level diode clamped inverter and a five-level cascaded H-bridge inverter. It first describes the operating principles and switching techniques of the two inverter topologies. It then presents the modeling of the BLDC motor. Simulation results are shown for the firing pulses, line voltages, stator currents, back EMF, speed, torque, etc. of the BLDC motor when powered by each inverter configuration. The performance of the motor fed by the two multilevel inverters is compared.
This document presents a novel particle swarm optimization technique to optimize PID controller parameters for controlling the speed of a linear brushless DC motor. The PSO algorithm is used to determine the optimal proportional, integral and derivative gains for the PID controller. Simulation results show that the proposed PSO-PID controller improves the dynamic performance of the motor system by reducing rise time, overshoot, settling time and steady state error.
This document contains an examination for the course Electrical Machines and Drives held at Universiti Tun Hussein Onn Malaysia. It consists of 6 questions testing knowledge of various electric machines including DC machines, transformers, induction motors, synchronous generators, shaded pole motors and reluctance motors. Students are instructed to answer 4 questions out of the 6 in the 2 hour and 12 minute examination.
This document summarizes a research paper that proposes a novel approach to designing a low power 6T (8x8) SRAM cell using MOS Current Mode Logic (MCML) technique at a 45nm technology node. Simulation results show that an SRAM cell array designed with MCML achieves significant reductions in power dissipation, leakage current, and static power compared to a conventional 6T SRAM cell design. At a supply voltage of 1.2V, the MCML design achieves a power dissipation of 128.6uW versus 480.3uW for the conventional design. The MCML design also exhibits lower leakage current, static power, power-delay product, and energy-delay product. Therefore
New Model Variable Frequency Transformer (NMVFT) – A Technology for V/f Contr...IDES Editor
Variable frequency transformer (VFT) is used as a
controllable bidirectional transmission device that can transfer
power between asynchronous networks and functionally is
similar to back-to-back HVDC. This paper describes the basic
concept of a New Model Variable Frequency Transformer
(NMVFT). NMVFT is a new technology which is used for v/f
control of induction motors. A digital simulation model of
NMVFT and its control system are developed using MATLAB.
The out power thus generated in v/f mode has been practically
verified for the speed control of a three-phase induction motor.
Thus constant speed-torque characteristics were achieved.
The left-hand rule for motors is used to determine the direction of force and motion produced on a current-carrying conductor in a magnetic field.
To use the left-hand rule:
1. Point the thumb of your left hand in the direction of the magnetic field lines.
2. Point your index finger in the direction of the current flowing through the conductor.
3. Your middle finger will now point in the direction of the force on the conductor due to the interaction of the current and magnetic field.
The direction of the force gives the direction of motion of the conductor. This principle is used in DC motors to generate a rotational motion from an electrical current.
Study of Low Voltage Cascode Current Mirror with Enhance Dynamic Rangeijsrd.com
The current mirror is one of most common building blocks both in analog and mixed mode VLSI circuits and the performance of analog structures largely depends on their characteristics. The current mirror can be used as an active element and as a biasing circuit. In this paper we study about the current mirror, cascode current mirror and different low voltage current mirror topology and study the literature survey. After that we study, analysis and design of convention Level shifted low voltage current mirror and TSPICE simulation technology. Presented analysis low voltage current mirror input –output characteristic, high output swing capability and wide input -output swing capabilities, suitable for low voltage operation and minimum power dissipation.
This document analyzes linear switched reluctance motors (LSRM). It begins by describing conventional switched reluctance motors (SRM) and their working principles. It then discusses the construction, working, and advantages of LSRM compared to SRM. Key differences between SRM and LSRM are that LSRM provide linear motion rather than rotational motion and have higher efficiency and power density. The document also covers applications of SRM and concludes by listing topics to be covered in a future review.
This document proposes a novel structure to improve the common mode rejection ratio (CMRR) of circuits like current buffers and folded cascode amplifiers. The proposed structure uses only four transistors and a current source to deviate common mode signals without affecting differential mode signals. This improves the CMRR by at least 12dB while preserving the CMRR bandwidth, which is a novel technique. The structure was applied to both a current buffer and folded cascode amplifier based on simulation results, demonstrating its effectiveness in improving CMRR.
The document discusses DC machines and their components and operation. It covers:
1) The basic principles of electromechanical energy conversion in DC machines including generation of electromotive force through Faraday's law of induction and development of torque when current carrying conductors are placed in a magnetic field.
2) The construction of DC machines including the field system, armature, commutator, and armature windings.
3) Equations for calculating induced emf, terminal voltage, torque, and motor/generator characteristics based on the machine components and operating parameters.
This document summarizes a paper that proposes a new approach to feature-based 3D modeling of turned components in AutoCAD. The approach develops algorithms to model features like cylinders, tapers, holes, and grooves based on user-entered dimensions. It then stores feature information and uses it to assess similarity between components. The modeling system supports both feature-based design and recognition without needing separate feature extraction. The paper presents the algorithms for modeling different features and assessing similarity based on common features like cylinders, holes, or grooves.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document presents a geometric programming model to optimize the production rate of a turning process. It develops a mathematical model to express the production time as a function of cutting parameters like cutting speed and feed rate. The objective is to minimize production time by determining the optimal cutting conditions. Experimental validation of the model shows it provides an efficient way to maximize production rate within operating constraints like maximum speed, feed rate, power requirements and surface roughness. The geometric programming technique offers advantages over other optimization methods for this application.
This document summarizes research on analyzing the steady-state performance of a self-excited induction generator using three optimization techniques: genetic algorithms, pattern search, and quasi-Newton methods. It provides background on induction generators and how they can operate as self-excited generators by connecting capacitors to the stator terminals. The document presents the standard steady-state equivalent circuit model and derives nonlinear equations that are solved using the three optimization techniques to determine unknown parameters. The performance of the self-excited induction generator is then evaluated based on the determined parameters.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document evaluates the performance of the AODV and DSR routing protocols for Variable Bit Rate (VBR) multimedia traffic in mobile ad hoc networks. It conducts simulations in NS-2 to analyze four performance metrics: packet received, throughput, routing overhead, and network load. The results show that AODV outperforms DSR for packet received, throughput, and routing overhead. DSR has higher network load than AODV. Therefore, the document concludes that AODV is better suited than DSR for VBR multimedia transmission in mobile ad hoc networks.
This document summarizes a study on wall pressure distribution in a suddenly expanded flow for an area ratio of 2.56. Experiments were conducted by attaching an enlarged duct to the exit of an axisymmetric convergent-divergent nozzle. Wall pressure was measured for nozzle pressure ratios of 3-11 and Mach numbers of 1.87, 2.2, and 2.58. Microjets were used as an active control method to study their effect on wall pressure distribution. Results showed that microjets did not adversely affect the oscillatory wall pressure field for most conditions tested. At Mach 2.58 and NPR of 9, microjets significantly increased the reattachment length in the duct. In general, microjets were found
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document summarizes a study analyzing the integrated land and watershed development of Dhobai Watershed in Dumka District, Jharkhand, India using GIS and geonomic analysis. The study aims to generate updated thematic information on natural resources to facilitate sustainable land and water management. Methodology included visual and digital interpretation of satellite imagery and topographical maps. Themes mapped included geomorphology, drainage, climate, soils, and land use/land cover. Geomorphological units identified include valleys, hills, and uplands. Drainage is dominated by the Dhobai River. Soils include Entisols, Inceptisols and Alfisols. Land use is primarily single
The document discusses the performance analysis of the MUSIC algorithm for direction of arrival (DOA) estimation using different antenna array configurations. It explores the MUSIC algorithm using a uniform linear array (ULA) and uniform circular array (UCA). Computer simulations were developed to evaluate the DOA performance of MUSIC based on ULA and UCA geometries. The performance obtained with both array configurations is analyzed through simulation results. A new proposed array geometry based on ULA is also presented and its performance is compared with ULA through simulation.
El poema describe cómo los amores del pasado pueden volverse inmunes al olvido y permanecer en la memoria como fantasmas de un idilio perdido. Estas heridas de amor quedan siempre abiertas y transforman nuestras vidas, aferrándose con bravía para recordarnos constantemente aunque estén distantemente. Son amores viejos e imborrables que se vuelven poco a poco inolvidables a pesar de estar lejos del alma.
O documento discute os diferentes níveis de construção do conhecimento acadêmico, como resumo, resenha e artigo. Também aborda a relevância dos trabalhos acadêmicos e como apresentá-los seguindo as normas da ABNT.
Speed Observer Based Load Angle Control of Induction Motor DriveIDES Editor
The performance of induction motor drives
gets improved in the scalar control mode with various
algorithms with speed /position feedback. In this paper
load angle control of induction motor with speed observer
is presented. This eliminates the physical presence of
speed sensor. The basic control of rotor flux vector with
stator current defines the dynamics of torque control. In
this scheme, estimation of feedback variables is obtained
by using algorithm with minimum number of machine
parameters. The speed obtained is thus used in feedback
loop to improve the machine performance. The proposed
algorithm also has a capability to estimate the active and
reactive power of the machine. This is further
incorporated to improve the operating efficiency of the
machine. The observer developed is tested for various
dynamics condition to verify its operating performance in
MATLAB/SIMULINK.
This document discusses improving the low voltage ride-through (LVRT) capability of doubly fed induction generator (DFIG)-based wind turbines using a dynamic voltage restorer (DVR). During faults, voltage dips can cause overcurrent and overvoltage in the DFIG rotor circuit if not compensated. The DVR is proposed to inject compensating voltage and prevent rapid changes in the stator voltage, allowing the rotor side converter to operate normally. Both symmetrical and asymmetrical voltage dips are investigated. Simulations using PSCAD/EMTDC verify the DVR approach improves the DFIG's LVRT capability with benefits of independent phase voltage compensation, lower volume, weight and cost compared to other solutions.
IRJET- Analysis the Speed Manage of BLDC Motor Drive using SensorsIRJET Journal
This document analyzes the speed control of a brushless DC motor (BLDC) using sensors. It begins with an introduction to BLDC motors and their advantages over brushed DC motors. It then presents the mathematical modeling of a BLDC motor, including voltage and flux linkage equations. It describes using Hall-effect sensors to sense the rotor position and control the motor. The document discusses using a PI controller for speed control and the challenges in selecting the PI gains. It concludes by presenting the methodology for mathematically modeling the motor, including the electrical and mechanical system dynamics equations.
IRJET - DFIG Control Design for Preventing SSR ModeIRJET Journal
This document presents a novel approach to designing a controller for a Doubly-Fed Induction Generator (DFIG) using Stator-Voltage-Oriented (SVO) vector control to prevent sub-synchronous resonance (SSR). It develops a state-space model of the DFIG including inner current loop dynamics and different feed-forward compensation schemes. The analysis shows that the stability of the DFIG and excitation of SSR modes depends mainly on the tuning of the proportional-integral controllers. Erroneous tuning can result in instability or SSR excitation. The paper contributes a tuning methodology for the PI controllers to secure stability and prevent SSR under SVO control.
Speed Control of Induction Motor Using Hysteresis MethodIRJET Journal
This document discusses speed control of an induction motor using a hysteresis control method. It begins with an abstract that outlines using hysteresis current control in the speed loop control design to optimize induction motor performance. It then discusses using an extended state observer to estimate disturbances and compensate the speed controller. The document provides background on induction motors, including details on their stator, squirrel cage and wound rotors. It also discusses using inverters like diode-clamped and flying-capacitor inverters to generate the AC voltages used to drive the motor.
Special electrical machines were invented for specific control applications. Reluctance motors include synchronous reluctance motors and switched reluctance motors. The switched reluctance motor induces magnetic poles on the rotor through magnetic reluctance. It has stator windings but no coils or magnets on the rotor. Torque is produced as the rotor moves to minimize reluctance. The switched reluctance motor uses power converters and position sensors for commutation and control.
ISSN 2395-650X
A Science Journal Publication serves as a reputable platform for the dissemination of scientific research and discoveries across a wide range of disciplines. These journals ensure the quality and accuracy of the research presented, fostering a collaborative environment where researchers share their insights, theories, and breakthroughs with the global scientific community.
Iaetsd a decisive fuzzy controlled single switch basedIaetsd Iaetsd
This document describes a proposed fuzzy logic controller for a switched reluctance motor (SRM) drive system. It presents a new single-switch converter topology for SRM drives that aims to improve performance with a simple design. Simulation results using Matlab/Simulink show that the proposed converter fed SRM drive has faster response and settling times under closed-loop control compared to open-loop operation, and further improvement when using a fuzzy logic controller. The fuzzy logic controller design and simulation results validating its ability to enhance the dynamic performance of the SRM drive are discussed.
Simulation and Analysis of 5 Phase SRM ConverterIRJET Journal
This document summarizes a simulation of a five-phase switched reluctance motor (SRM) drive. Key points:
1) A simulation was performed of a 10/8 pole five-phase SRM drive using a converter with two IGBTs and two diodes per phase.
2) The simulation analyzed motor parameters such as phase flux, armature current, torque, and speed. It was observed that the motor draws ripple current and develops ripple torque corresponding to the phase current.
3) The motor speed settled at 1100 rpm with the phase flux exhibiting a triangular waveform with 72 degree phase shift between phases.
This document summarizes a research paper that proposes a new switched capacitance power converter for a 6/4 switched reluctance motor drive. The proposed converter aims to reduce torque ripple and allow constant speed to be achieved more quickly with reduced power loss compared to an asymmetric converter. The operating principles and design of the proposed converter are described. Simulation results using MATLAB Simulink show that the proposed converter produces less torque oscillation and maintains a constant speed of 4500 RPM, making it suitable for low and medium speed applications.
Improvement of Transient Stability in Doubly Fed Induction Wind Generator usi...IRJET Journal
This document discusses improving transient stability in doubly fed induction wind generators using a bridge-type fault current limiter (BFCL). It first provides background on doubly fed induction generators and introduces the BFCL. It then describes modeling the generator, controllers, BFCL, and compares the BFCL to a series dynamic braking resistor for limiting fault current. Simulation results are presented and show the BFCL more effectively improves transient stability during symmetrical and asymmetrical faults compared to the resistor. The conclusion is that the BFCL is very efficient at improving transient stability in doubly fed induction generator-based wind farms to meet grid code requirements, and performs better than the resistor except for cost.
Life Cycle of Big Data Analysis by using MapReduce AlgorithmIRJET Journal
This document discusses improving transient stability in doubly fed induction wind generators using a bridge-type fault current limiter (BFCL). It first provides background on doubly fed induction generators and introduces the BFCL. It then describes modeling the wind turbine, doubly fed induction generator, rotor and grid side controllers. Operation and control of the BFCL is explained and compared to a series dynamic braking resistor (SDBR) approach. Simulation results show the BFCL more effectively improves transient stability during faults compared to the SDBR. The document concludes the BFCL is very efficient at improving transient stability in doubly fed induction generator-based variable speed wind turbines to meet grid code requirements, and is more effective than SDBR except for potential
Design and Implementation of an Efficient Soft Switching Inverter Fed Ac DriveIRJET Journal
This document describes the design and implementation of an efficient soft switching inverter for AC motor drives. Soft switching reduces switch stresses and losses compared to hard switching. The proposed design uses a PWM generator and MOSFET driver to generate high frequency AC from a DC source. A transformer steps up the voltage which is then rectified and given to an H-bridge soft switching inverter. This produces a sinusoidal output to drive an AC motor. Current and voltage sensing circuits protect the system from overcurrent and undervoltage. Simulation results show the soft switching inverter has higher efficiency (97.78%) than a hard switching converter due to lower switching losses. It also operates at higher power levels with less heat sink temperature rise.
Vector Controlled Two Phase Induction Motor and To A Three Phase Induction MotorIJERA Editor
This paper presents vector controlled of single phase induction motor. some problems are with vector controlled SPIM.As SPIM’s are typically to maintain speed and also about the complex implementation of vector controlled SPIM.the implemantion of the proposed vector controlled TPIM compared to the vector controlled SPIM. The general modal sutable for vector control of the unsymmentrical two phase induction motor and also stator flux oriented controlled strategies are analized. the comparative performance of both has been presented in this work with help of a practical three phase motor.
The Self Excited Induction Generator with Observation Magnetizing Characteris...IJPEDS-IAES
This paper discusses The Self Excitated Induction Generator (SEIG) by approaching the induction machine, physically and mathematically which then transformed from three-phase frame abc to two-axis frame, direct-axis and quadratur-axis. Based on the reactive power demand of the induction machine, capacitor mounted on the stator of the induction machine then does the physical and mathematical approach of the system to obtain a space state model. Under known relationships, magnetization reactance and magnetizing current is not linear, so do mathematical approach to the magnetization reactance and magnetization current characteristic curve to obtain the magnetization reactance equation used in the calculation. Obtained state space model and the magnetic reactance equation is simulated by using Runge Kutta method of fourth order. The equations of reactance, is simulated by first using the polynomial equation and second using the exponent equation, and then to compare those result between the polynomial and exponent equations. The load voltage at d axis and q axis using the polynomial lags 640μs to the exponent equation. The polynomial voltage magnitude is less than 0.6068Volt from the exponent voltage magnitude.
The document analyzes the steady state and dynamic performance of doubly fed induction generators (DFIGs) used in wind turbines. It begins with an introduction to DFIGs and their advantages over squirrel cage induction generators. It then presents:
1) A steady state analysis of a DFIG operating at different slips and the control of real and reactive power output through rotor voltage control.
2) A closed form dynamic analysis using flux voltage transformations to compare with steady state results.
3) Simulations of a DFIG operating as a motor under no load, varying load conditions, and as a generator under constant and changing wind speeds.
4) The results show the DFIG's ability to control
This document presents a comparative study of different sensorless speed estimation methods for permanent magnet synchronous motor (PMSM) drives. It discusses several categories of estimation methods, including fundamental excitation methods (both non-adaptive and adaptive), saliency and signal injection methods, and artificial intelligence methods. Fundamental excitation methods that use monitored voltages and currents or estimate flux are described. The document also highlights challenges with sensorless control at low speeds, such as errors from data acquisition, voltage distortion, and parameter variations. Overall, the document provides an overview of common sensorless speed estimation techniques for PMSMs and compares their advantages and disadvantages.
Closed Loop Speed Control of a BLDC Motor Drive Using Adaptive Fuzzy Tuned PI...IJERA Editor
Brushless DC Motors are widely used for many industrial applications because of their high efficiency, high
torque and low volume. This paper proposed an improved Adaptive Fuzzy PI controller to control the speed of
BLDC motor. This paper provides an overview of different tuning methods of PID Controller applied to control
the speed of the transfer function model of the BLDC motor drive and then to the mathematical model of the
BLDC motor drive. It is difficult to tune the parameters and get satisfied control characteristics by using normal
conventional PI controller. The experimental results verify that Adaptive Fuzzy PI controller has better control
performance than the conventional PI controller. The modeling, control and simulation of the BLDC motor have
been done using the MATLAB/SIMULINK software. Also, the dynamic characteristics of the BLDC motor (i.e.
speed and torque) as well as currents and voltages of the inverter components are observed by using the
developed model.
14. a variable speed, sensorless, induction motor drivesatya_m
The document presents a new sensorless control strategy for a three-phase induction motor drive using only DC link current measurements. The strategy estimates motor speed and torque through signal reconstruction rather than direct sensor readings. It includes independent speed and torque control loops as well as current regulation. Simulation results on a 2.2 kW induction motor show fast dynamic response and good agreement between actual and estimated torque and speed values. The proposed drive requires only one current sensor in the DC link, making it suitable for low-cost sensorless motor applications.
This document describes a study on controlling the speed of a brushless DC motor using a microcontroller. It provides background on brushless DC motors, including their construction, advantages over brushed DC motors, and typical control method using Hall sensors and electronic commutation of the phases. The document then presents the dynamic model of a brushless DC motor, including equations for the back EMF, torque production, motor position and speed. It describes the hardware components used, including the brushless DC motor, Hall sensors, inverter, and microcontroller. The goal is to design a low-cost microcontroller-based speed control system for the brushless DC motor.
1. Y.Sumith, J.S.V.Siva Kumar / International Journal of Engineering Research and Applications
(IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.1668-1674
Estimation Of parameter For Induction Motor Drive
Y.Sumith*, J.S.V.Siva Kumar
*
PG Scholar, E.E.E Dept., G.M.R Institute of Technology, Rajam , Andhra Pradesh, India
**
Assistant Professor, E.E.E Dept., G.M.R Institute of Technology, Rajam , Andhra Pradesh, India
ABSTRACT
Generally speed measurement is done high speed switching devices such as IGBTs were
with sensor, but disadvantage of sensor is introduced and more precise motor control
difficult to measure speed at low speeds with strategies, such as vector control techniques, were
sensor. These difficulties are eliminated by using developed. As a result, today IMs can be used in any
sensor less Flux Orientation Controlled (FOC) . kind of variable speed applications, even as a
This paper proposes a Model Reference servomechanism, where high-speed response and
Adaptive System (MRAS) for estimation of rotor extreme accuracy is required.
speed in FOC. An Induction motor is developed
in stationary reference frame and Space Vector The two names for the same type of motor,
Modulation (SVM) is used for inverter induction motor and asynchronous motor, describe
design.PID controllers are designed for this FOC. the two characteristics in which this type of motor
It has good tracking and attains steady state differs from DC motors and synchronous motors.
response very quickly which is shown in Induction refers to the fact that the field in the rotor
simulation results. is induced by the stator currents, and asynchronous
refers to the fact that the rotor speed is not equal to
Keywords – Sensor less field orientation control the stator frequency. No sliding contacts and
(FOC), Model Reference Adaptive System permanent magnets are needed to make an IM work,
(MRAS), Induction motor drive, Speed which makes it very simple and cheap to
estimation. manufacture. As motors, they rugged and require
very little maintenance. However, their speeds are
1. INTRODUCTION not as easily controlled as with DC motors. They
Induction motor (IM) can be considered as draw large starting currents, and operate with a poor
the ‘workhorse’ of the industry because of its lagging factor when lightly loaded.
special features such as low cost, high reliability,
low inertia, simplicity and ruggedness. Even today 2.DYNAMIC MODELING OF
IMs especially the squirrel cage type, are widely INDUCTION MACHINE
used for single speed applications rather than Generally, an IM can be described uniquely
variable speed applications due to the complexity of in arbitrary rotating frame, stationary reference
controlling algorithm and higher production cost of frame or synchronously rotating frame. For transient
IM. studies of adjustable speed drives, it is usually more
convenient to simulate an IM and its converter on a
Variable speed drives. However, there is a stationary reference frame. Moreover, calculations
great interest on variable speed operation of IM with stationary reference frame are less complex due
within the research community mainly because IMs to zero frame speed. For small signal stability
can be considered as a major industrial load of a analysis about some operating condition, a
power system. On the other hand the IMs consume a synchronously rotating frame which yields steady
considerable amount of electricity generated. The values of steady-state voltages and currents under
majority of IMs are operated at constant speed, balanced conditions is used.
determined by the pole pair number and the stator From the below figure the terminal voltages are as
supply frequency. follows,
Vqs = Rqiqs + p (Lqqiqs) + p (Lqdids) + p (Lq i ) + p
It is well known fact that electric energy
(Lqi)
consumption of the appliances can be reduced by
Vds = p (Ldqiqs) + Rdids + p (Lddids) + p (Ldi) + p
controlling the speed of the motor. The three phase
variable speed IM drives are therefore encouraged to (Ldi) (1)
be used in the industry today as an attractive V = p (Lqiqs) + p (Ldids)+ Ri + p (Li) + p
solution forever increasing electricity generation (Li)
cost. V = p (Lqiqs) + p (Ldids) + p (Li) + R i + p
(Li)
During the last decade, with the
advancement of power electronics technology, a
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(IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.1668-1674
frame dynamic model.
The dynamic equations of the induction motor in
any reference frame can be represented by using
flux linkages as variables. This involves the
reduction of a number of variables in the dynamic
equations. Even when the voltages and currents are
discontinuous the flux linkages are continuous. The
stator and rotor flux linkages in the stator reference
frame are defined as
qs Ls iqs Lm iqr
ds Ls ids Lm idr
-------------- (2)
Fig .1 Two-phase equivalent diagram of induction
motor qr Lr iqr Lm iqs
Where p is the differential operator d/dt, dr Lr idr Lm ids
and vqs, vds are the terminal voltages of the stator q
axis and d axis. V, V are the voltages of rotor qm Lm (iqs iqr )
and windings, respectively. is and ids are the stator
-------------- (3)
q axis and d axis currents. Whereas i and i are the
dm Lm (ids idr )
rotor and winding currents, respectively and Lqq,
Stator and rotor voltage and current equations
Ldd, L and L are the stator q and d axis winding
are as follows
and rotor and winding self-inductances,
respectively. vds Rs ids p ds
The following are the assumptions made in vqs Rs iqs p qs
order to simplify
vdr Rr idr r qr p dr
-------------- (4)
i. Uniform air-gap
ii. Balanced rotor and stator vqr Rr iqr r dr p qr
windings with sinusoidal distributed mmfs
Since the rotor windings are short circuited,
iii. Inductance in rotor position is
the rotor voltages are zero. Therefore
sinusoidal and
iv. Saturation and parameter changes Rr idr r qr p dr 0
are neglected
Rr iqr r dr p qr 0
---------------- (5)
The rotor equations are refereed to stator side as in
the case of transformer equivalent circuit. From this, From (5), we have
the physical isolation between stator and rotor d-q
p dr r qr
axis is eliminated. i dr
Rr
p qr r dr
-------------- (6)
i qr
Rr
By solving the equations (4)-(6) we get the
following equations
ds (vds Rs ids )dt ---------------- (7)
qs (vqs Rs iqs )dt ----------------- (8)
Lr r qr Lm ids Rr
dr ------------------ (9)
Rr sLr
Figure 2 (b) Dynamic de-qe equivalent circuits of Lr r dr Lm Rr iqs
machine (a) qe-axis circuit, (b) de-axis circuit qr ------------------ (10)
Rr sLr
Figure 2 shows the de-qe dynamic model
equivalent circuit of induction motor under
synchronously rotating reference frame, if vqr = vdr =
0 and we=0 then it becomes stationary reference
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Vol. 2, Issue 5, September- October 2012, pp.1668-1674
vds dr .sLm output.
ids ------------- (11)
Rs sLs Lr .(Rs sLs )
vqs qr .sLm
iqs ------------- (12)
Rs sLs Lr .(Rs sLs )
The electromagnetic torque of the induction motor
in stator reference frame is given by
3 p
Te Lm (iqs idr ids iqr ) -------------- (13)
22
3 p Lm
or Te (iqs dr ids qr ) --------------(14)
2 2 Lr
Fig 4: Schematic diagram of voltage source inverter
3. PRINCIPLE OF VECTOR CONTROL
The fundamentals of vector control can be In reality, there are only six nonzero voltage vectors
explained with the help of figure 3, where the and two zero voltage vectors as shown in Fig 5(a) &
machine model is represented in a synchronously (b).
rotating reference frame.
Fig 3 Basic block diagram of vector control
Vector control implementation principle
with machine ds-qs model as shown The controller
makes two stages of inverse transformation, as
shown, so that the control currents and
(a)
i * correspond to the machine currents ids and iqs,
qs
respectively. In addition, the unit vector assures
correct alignment of ids current with the flux vector
^
r and iqs perpendicular to it, as shown. It can be
noted that the transformation and inverse
transformation including the inverter ideally do not
incorporate any dynamics, and therefore, the
response to ids and iqs is instantaneous (neglecting
computational and sampling delays).
(b)
Fig 5(a) Inverter Switching Stages, (b) Switching –
4. INVERTER voltage space vectors
Processing of the torque status output and The machine voltages corresponding to the
the flux status output is handled by the optimal switching states can be calculated by using the
switching logic. Fig (4) shows the schematic following relations.
diagram of voltage source inverter. The function of
the optimal switching logic is to select the
appropriate stator voltage vector that will satisfy
both the torque status output and the flux status
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v ab v a v b model. The model that has the quantity to be
estimated involved is considered as the adaptive
v bc v b v c -------------------------- (15) model (or adjustable model). The output of the
v ca v c v a
adaptive model is compared with that of the
reference model, and the difference is used to drive
a suitable adaptive mechanism whose output is the
Sensor less vector control induction motor quantity to be estimated (the rotor speed). The
drive essentially means vector control without any adaptive mechanism should be designed to assure
speed sensor. An incremental shaft mounted speed the stability of the control system. A successful
encoder, usually an optical type is required for MRAS design can yield the desired values with less
closed loop speed or position control in both vector computational error (especially the rotor flux based
control and scalar controlled drives. A speed signal MRAS) than an open loop calculation and often
is also required in indirect vector control in the simpler to implement.
whole speed range and in direct vector control for
the low speed range, including the zero speed start The model reference adaptive system
up operation. Speed encoders undesirable in a drive (MRAS) is one of the major approaches for adaptive
because it adds cost and reliability problems, control [6]. The model reference adaptive system
besides the need for a shaft extension and mounting (MRAS) is one of many promising techniques
arrangement. employed in adaptive control. Among various types
of adaptive system configuration, MRAS is
important since it leads to relatively easy- to-
implement systems with high speed of adaptation
for a wide range of applications.
Fig 6:Block Diagram of Sensor less Control of
Induction Motor
The schematic diagram of control strategy
of induction motor with sensor less control is shown
in Fig 4.. Sensor less control induction motor drive Fig 7: basic identification structures and their
essentially means vector control without any speed correspondence with MRAS
sensor [5]. The inherent coupling of motor is
eliminated by controlling the motor by vector The basic scheme of the MRAS given in
control, like in the case of as a separately excited Fig. 7 is called a parallel (output error method)
motor. The inverter provides switching pulses for MRAS in order to differentiate it from other MRAS
the control of the motor. The flux and speed configurations where the relative placement of the
estimators are used to estimate the flux and speed reference model and of a adjustable system is not
respectively. These signals then compared with the same. The MRAS scheme presented above are
reference values and controlled by using the PI characterized by the fact that the reference model
controller. was disposed in parallel with the adjustable system.
In this scheme the reference and adjustable models
5. MODEL REFERENCING ADAPTIVE are located in series [6]. The use of parallel MRAS
SYSTEM (MRAS) is determined by its excellent noise-rejection proper-
Tamai [5] has proposed one speed ties that allow obtaining unbiased parameter
estimation technique based on the Model Reference estimates. By contrast, ‘‘series–parallel’’ MRAS
Adaptive System (MRAS) in 1987. Two years later, configurations always lead to biased parameter
Schauder [6] presented an alternative MRAS estimations in presence of measurement noise [8].
scheme which is less complex and more effective. Reference model equations:
Lr L2
The MRAS approach uses two models. The model r ( (U s Rs is )dt ( Ls m )is ) ------ (16)
that does not involve the quantity to be estimated Lm Lr
(the rotor speed, ωr) is considered as the reference
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Vol. 2, Issue 5, September- October 2012, pp.1668-1674
Lr L2 axes voltages and load torque. The outputs are direct
r ( (U s Rs is )dt ( Ls m )is ) ---- (17) and quadrate axis rotor fluxes, direct and quadrature
Lm Lr
axes stator currents, electrical torque developed and
Adjustable model equations
rotor speed.
d r L m
is r r r ------------ (18)
dt Tr Tr
d r Lm r
is r r ------------ (19)
dt Tr Tr
Error between reference and adjustable models:
r r r r --------------------- (20)
Estimated speed from PI controller is
r K p w Ki wdt --------------------- (21)
6. VECTOR CONTROL OF INDUCTION
MOTOR DRIVE:
The Vector Control or Field orientation
control of induction motor is simulated on
MATLAB/SIMULINK - platform to study the
various aspects of the controller. The actual system
Fig.9: Simulink block diagram for induction motor
can be modeled with a high degree of accuracy in
model
this package. It provides a user interactive platform
and a wide variety of numerical algorithms. This
6.2 INVERTER
chapter discusses the realization of vector control of Fig 4 shows the Voltage Source Inverter
induction motor using Simulink blocks.
(VSI), it consists of an Optimal Switching Logic
Fig.8 shows the Vector controlled which is shown in Fig 10. The function of the
Induction Motor block simulink diagram for optimal switching logic is to select the appropriate
simulation. This system consisting of Induction stator voltage vector that will satisfy both the torque
Motor Model, Three Phase to Two phase
status output and the flux status output. Processing
transformation block, Two phase to Three phase
of the torque status output and the flux status output
block, Flux estimator block and Inverter block.
is handled by the optimal switching logic.
Fig 10 Voltage Source Inverter
Fig 8: Simulink Model of Vector Controlled 6.3 Model Refernce Adaptive System (MRAS)
Induction motor Fig 11 shows the simulink block diagram
Model Referencing Adaptive System (MRAS).
6.1 Induction Motor Model: Which is consists Two blocks one is called
The motor is modeled in stator reference Reference Model and other is Adaptive Model. The
frame. The dynamic equations are given by (1) to voltage model’s stator-side equations, (16) & (17)
(14). By using these equations we can develop the are defined as a Reference Model and the simulink
induction motor model in stator reference frame. block diagram of Reference Model is shown in
Fig.9 shows the simulink block diagram for motor Fig11. The Adaptive Model receives the machine
model. Inputs to this block are direct and quadrature stator voltage and current signals and calculates the
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Vol. 2, Issue 5, September- October 2012, pp.1668-1674
rotor flux vector signals, as indicated by equations, MATLAB/SIMULINK. The results for different
(18) and (19) which is shown in Fig 11. By using cases are given below.
suitable adaptive mechanism the speed r, can be (a)Reference speed = 100 rad/sec and on no-load
estimated and taken as feedback.
Fig 11: Simulink block diagram for Model
Referencing Adaptive System
6.4 Sensor less control of induction motor
The Sensor less control of induction motor
using Model Reference Adaptive System (MRAS) is
simulated on MATLAB/SIMULINK - platform to
study the various aspects of the controller. The
actual system can be modeled with a high degree of
Fig 13: 3- currents, Speed, and Torque for no-load
accuracy in this package. It provides a user
reference speed of 100 rad/sec
interactive platform and a wide variety of numerical
algorithms. Here we are going to discuss the
realization of Sensor less control of induction motor
using MRAS for simulink blocks. Fig. 12 shows the
root-block simulink diagram for simulation. Main
subsystems are the 3-phase to 2-phase
transformation, 2-phase to 3-phase transformation,
induction motor model, Model Reference Adaptive
System (MRAS) and optimal switching logic &
inverter.
Fig 14: Reference speed, Rotor Speed, Slip Speed
Respectively
Fig 12: Simulink root block diagram of Sensorless
control of induction motor using MRAS
(b)Reference speed = 100 rad/sec; Load torque of 15
N-m is applied at t = 1.5 sec
7. SIMULATION RESULTS
The simulation of Vector Control of
Induction Motor is done by using
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torque wave and also the starting current is high.
The main results obtained from the Simulation, the
following observations are made.
i) The transient response of the drive is fast,
i.e. we are attaining steady state very quickly.
ii) The speed response is same for both vector
control and Sensor less control.
iii) By using MRAS we are estimating the
speed, which is same as that of actual speed of
induction motor.
Thus by using sensor less control we can
get the same results as that of vector control without
shaft encoder. Hence by using this proposed
technique, we can reduce the cost of drive i.e. shaft
encoder’s cost, we can also increase the ruggedness
of the motor as well as fast dynamic response can be
achieved.
Fig 15: 3- currents, Speed, and Torque for no-load
reference speed of 100 rad/sec REFERENCES
1. Abbondanti, A. and Brennen, M.B. (1975).
Variable speed induction motor drives use
electronic slip calculator based on motor
voltages and currents. IEEE Transactions
on Industrial Applications, vol. IA-11, no.
5: pp. 483-488.
2. Nabae, A. (1982). Inverter fed induction
motor drive system with and instantaneous
slip estimation circuit. Int. Power
Electronics Conf., pp. 322-327.
3. Jotten, R. and Maeder, G. (1983). Control
methods for good dynamic performance
induction motor drives based on current
and voltages as measured quantities. IEEE
Transactions on Industrial Applications,
vol. IA-19, no. 3: pp. 356-363.
4. Baader, U., Depenbrock, M. and Gierse, G.
(1989). Direct self control of inverter-fed
induction machine, a
5. Tamai, S. (1987). Speed sensorless vector
Fig 16: Reference speed, Rotor Speed, Slip Speed control of induction motor with model
Respectively reference adaptive system. Int. Industry
Applications Society. pp. 189-195.
7.1. Conclusion 6. Griva, G., Profumo, F., Illas, C.,
In this thesis, Sensorless control of induction motor Magueranu, R. and Vranka, P. (1996). A
using Model Reference Adaptive System (MRAS) unitary approach to speed sensorless
technique has been proposed. Sensorless control induction motor field oriented drives based
gives the benefits of Vector control without using on various model reference schemes.
any shaft encoder. In this thesis the principle of IEEE/IAS Annual Meeting, pp. 1594-1599.
vector control and Sensorless control of induction 7. Viorel, I. A. and Hedesiu, H. (1999). On
motor is given elaborately. The mathematical model the induction motors speed estimator’s
of the drive system has been developed and results robustness against their parameters. IEEE
have been simulated. Simulation results of Vector Journal. pp. 931-934.
Control and Sensorless Control of induction motor 8. Amstrong, G. J., Atkinson, D. J. and
using MRAS technique were carried out by using Acarnley, P. P. (1997). A comparison of
Matlab/Simulink and from the analysis of the estimation techniques for sensorless vector
simulation results, the transient and steady state controller induction motor drives. Proc. Of
performance of the drive have been presented and IEEE-PEDS.
analyzed.
From the simulation results, it can be
observed that, in steady state there are ripples in
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