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
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.
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.
Design of a Linear and Non-linear controller for Induction MotorIJMTST Journal
This document describes the design of linear and non-linear controllers for an induction motor. It begins by introducing induction motors and their nonlinear dynamics. It then presents the mathematical model of an induction motor. Next, it describes the design of linear controllers using PID and LQR techniques by first linearizing the nonlinear system model. It also discusses designing a nonlinear controller using feedback linearization. Simulation results are presented to compare the performance of the designed controllers for speed control of the induction motor. The overall aim is to achieve speed control over a wide range using these advanced linear and nonlinear control techniques.
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.
Adaption of motor paramenters in sensorless pmsm driverwarluck88
The document proposes an online method for estimating the stator resistance and permanent magnet flux in sensorless permanent magnet synchronous motor drives. An adaptive observer augmented with high-frequency signal injection is used. Excess information in the observer is used to adapt the motor parameters. At low speeds, stator resistance is estimated from a speed correction term. At medium and high speeds, permanent magnet flux is estimated from d-axis current estimation error. Steady-state and small-signal analyses investigate parameter estimation sensitivity. Adaptation laws are designed for parameter convergence shown via simulation and experiment. Stator resistance adaptation works down to zero speed in sensorless control.
Inertia identification based on adaptive interconnected Observer of Permanent...IJRES Journal
In order to achieve the inertia identification of permanent magnet synchronous motor, this paper
presents an adaptive inter connected observer based on model reference adaptive and Rhomberg observer to
observe the inertia of permanent magnet synchronous motor and build the simulation model in MATLAB. By the
simulation analysis, the observer can identify the moment of inertia of permanent magnet synchronous motor
accurately, at the same time has good robustness.
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.
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.
Design of a Linear and Non-linear controller for Induction MotorIJMTST Journal
This document describes the design of linear and non-linear controllers for an induction motor. It begins by introducing induction motors and their nonlinear dynamics. It then presents the mathematical model of an induction motor. Next, it describes the design of linear controllers using PID and LQR techniques by first linearizing the nonlinear system model. It also discusses designing a nonlinear controller using feedback linearization. Simulation results are presented to compare the performance of the designed controllers for speed control of the induction motor. The overall aim is to achieve speed control over a wide range using these advanced linear and nonlinear control techniques.
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.
Adaption of motor paramenters in sensorless pmsm driverwarluck88
The document proposes an online method for estimating the stator resistance and permanent magnet flux in sensorless permanent magnet synchronous motor drives. An adaptive observer augmented with high-frequency signal injection is used. Excess information in the observer is used to adapt the motor parameters. At low speeds, stator resistance is estimated from a speed correction term. At medium and high speeds, permanent magnet flux is estimated from d-axis current estimation error. Steady-state and small-signal analyses investigate parameter estimation sensitivity. Adaptation laws are designed for parameter convergence shown via simulation and experiment. Stator resistance adaptation works down to zero speed in sensorless control.
Inertia identification based on adaptive interconnected Observer of Permanent...IJRES Journal
In order to achieve the inertia identification of permanent magnet synchronous motor, this paper
presents an adaptive inter connected observer based on model reference adaptive and Rhomberg observer to
observe the inertia of permanent magnet synchronous motor and build the simulation model in MATLAB. By the
simulation analysis, the observer can identify the moment of inertia of permanent magnet synchronous motor
accurately, at the same time has good robustness.
For special power requirements of the laser module, which is consist of the multiple laser diode(LD) chips series driven and the power of sythetic by combining the fiber, a small high-efficiency laser current source component is desighed and developd, and a small high-efficienct semiconductor cooling thermal electrical cooler (TEC) fiber-coupled laser module temperature controlling comp onenr is presented as well. The component operting temperature
range is from -45℃ to 55℃, and the result that the design can meet the performance reauirements has been proved in the experiment. The mathematical model of LD established. The digital design method of a laser current source controlling circuit is presented, and achieved using ADuC831. The temperature controlling component structure of a LD module based on the TEC is introduced, a simplified mathermatical model of the temperature control component is established, and the coefficient of operating current I of TEC are optimized to solve the problem of laser output wavelngth drifting with temperature.
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.
3.[14 28]space vector based dual zero-vector random centered distribution pwm...Alexander Decker
This document presents a novel dual zero-vector random centered distribution PWM (DZRCDPWM) algorithm for direct torque controlled induction motor drive to reduce acoustic noise. The proposed algorithm uses two zero voltage vectors (V0 and V7) and selects one randomly based on the operating modulation index. Simulation results show the DZRCDPWM algorithm reduces acoustic noise harmonics compared to the conventional SVPWM algorithm by distributing the pulse patterns randomly. The DZRCDPWM provides better performance over the entire modulation index range for induction motor drive control with reduced acoustic noise.
11.space vector based dual zero vector random centered distribution pwm algor...Alexander Decker
This document presents a novel dual zero-vector random centered distribution PWM (DZRCDPWM) algorithm for direct torque controlled induction motor drive to reduce acoustic noise. The proposed algorithm uses two zero voltage vectors (V0 and V7) and selects one randomly based on the operating modulation index. Simulation results show the DZRCDPWM algorithm reduces acoustic noise harmonics compared to the conventional SVPWM algorithm by distributing the pulse patterns randomly. The DZRCDPWM provides better performance over the entire modulation index range for induction motor drive control with reduced acoustic noise.
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.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
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 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.
Performance Improvement of Multi Level Inverter fed Vector Controlled Inducti...IJPEDS-IAES
In this paper, the analysis of space vector based multi level inverter (MLI) fed vector controlled induction motor drive for a low speed operation is presented. The performance of indirect field oriented controlled induction motor drive (IMD) is poor with two-level inverter for low speed operations (LSO). The reduction in performance and peak value of torque are mainly due to the non-linearity caused by stator voltage drop and inverter. Hence the performance factors of induction motor drive are analyzed with the multi level inverters under different operating conditions. In this approach, the steady state ripple content in the current and torque waveforms are reduced and that to ripple content of torque is reduced from 0.15 to 0.05 under steady state with five-level inverter. When there is a step change in the load torque, the momentary decrease in speed with five-level inverter is less when compared two and three-level inverters and the speed response reaches the reference value very quickly with five-level inverter during steady state and transient periods. So the overall performance of drive is improved with five- level inverter when compared to two-level and three- level inverters under low speed operations.
This document summarizes a paper that models and simulates a switched reluctance motor (SRM) to minimize torque ripple through different converter topologies and control strategies. The paper develops a mathematical model of a 6/4 SRM in Matlab/Simulink. It simulates the motor with asymmetric, Miller, and modified Miller converters. Torque ripple is evaluated using power spectrum density analysis. The modified Miller converter shows better performance in minimizing torque ripple compared to the other topologies. The document concludes the modified Miller converter combined with closed-loop control can effectively reduce torque ripple in SRM for high-speed applications.
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.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
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 an experimental study on the use of neem methyl esters as biodiesel in a compression ignition engine. Neem oil was transesterified to produce biodiesel, which was then blended with diesel in ratios of 10%, 20%, and 30% by volume. The blends were tested in a single cylinder diesel engine and performance and emission characteristics were analyzed at varying loads. Results showed that the B20 blend performed better than diesel with lower emissions. Higher blend ratios like B30 saw decreased performance due to higher viscosity negatively impacting combustion. Overall, the study demonstrated the potential of neem biodiesel to replace a portion of diesel fuel.
This document summarizes a research paper that proposes a new routing protocol called U-LEACH for wireless sensor networks. U-LEACH aims to prolong the lifetime of sensor networks by uniformly distributing cluster head selection throughout the network, unlike the original LEACH protocol. It describes how LEACH works and its limitations in ensuring uniform cluster head distribution. The proposed U-LEACH protocol incorporates a Uniform Distribution Technique to select cluster heads in a way that ensures each sensor node is within transmission range of a cluster head, extending the overall network lifetime.
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 speech encryption system that aims to enhance security. It uses chaotic maps to generate a polynomial, which is then used to generate a large set of Kasami sequences. These sequences act as the encryption key. The speech signal is divided into segments and encrypted using AES-128 with the Kasami sequences. Evaluation using noise attacks shows the encrypted speech has high distortion measures, indicating low residual intelligibility and therefore high security. Linear prediction analysis, spectral distance, and cepstrum distance are used to analyze the original and encrypted speech signals. Results demonstrate the proposed system encrypts speech effectively while maintaining good audio quality.
The document summarizes advances in electronic nose technologies. It discusses the historical development of electronic noses from the 1950s to present. It describes the four main sensor types used in electronic noses: metal oxide semiconductors, metal oxide semiconductor field-effect transistors, conducting polymer sensors, and piezoelectric acoustic sensors. Each sensor type is explained in terms of its sensitive material, detection principle, and factors that influence selectivity and sensitivity. The document provides an overview of electronic nose technologies and the sensor types commonly used.
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 analyzes the dose linearity response of thermoluminescence in ternary mixed multiphased crystals of (KCl)x(KBr)y-x(KI)1-y that were prepared by melt method and irradiated with 15MV photon beams. Nine combinations of the crystals were irradiated at doses of 10, 50, 100, and 200Gy. Thermoluminescence glow curves were studied from 50-400°C at a heating rate of 3°C/sec. The (KCl)0.1(KBr)0.8(KI)0.1 composition showed a maximum TL output at 100Gy with a glow peak around 85°C
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 a hybrid multilevel converter topology combining a neutral point clamped (NPC) converter with floating DC-link cascaded H-bridge converters. The NPC provides the active power while the H-bridges operate as series active filters to improve the voltage waveform quality by handling reactive power. This reduces the need for large passive filters. The document outlines two design challenges: determining the lowest H-bridge DC-link voltage to achieve adequate harmonic compensation, and developing a control algorithm to regulate the floating DC-link voltages at this level. Experimental results are provided to validate the proposed modulation technique and improvement in output waveform quality.
For special power requirements of the laser module, which is consist of the multiple laser diode(LD) chips series driven and the power of sythetic by combining the fiber, a small high-efficiency laser current source component is desighed and developd, and a small high-efficienct semiconductor cooling thermal electrical cooler (TEC) fiber-coupled laser module temperature controlling comp onenr is presented as well. The component operting temperature
range is from -45℃ to 55℃, and the result that the design can meet the performance reauirements has been proved in the experiment. The mathematical model of LD established. The digital design method of a laser current source controlling circuit is presented, and achieved using ADuC831. The temperature controlling component structure of a LD module based on the TEC is introduced, a simplified mathermatical model of the temperature control component is established, and the coefficient of operating current I of TEC are optimized to solve the problem of laser output wavelngth drifting with temperature.
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.
3.[14 28]space vector based dual zero-vector random centered distribution pwm...Alexander Decker
This document presents a novel dual zero-vector random centered distribution PWM (DZRCDPWM) algorithm for direct torque controlled induction motor drive to reduce acoustic noise. The proposed algorithm uses two zero voltage vectors (V0 and V7) and selects one randomly based on the operating modulation index. Simulation results show the DZRCDPWM algorithm reduces acoustic noise harmonics compared to the conventional SVPWM algorithm by distributing the pulse patterns randomly. The DZRCDPWM provides better performance over the entire modulation index range for induction motor drive control with reduced acoustic noise.
11.space vector based dual zero vector random centered distribution pwm algor...Alexander Decker
This document presents a novel dual zero-vector random centered distribution PWM (DZRCDPWM) algorithm for direct torque controlled induction motor drive to reduce acoustic noise. The proposed algorithm uses two zero voltage vectors (V0 and V7) and selects one randomly based on the operating modulation index. Simulation results show the DZRCDPWM algorithm reduces acoustic noise harmonics compared to the conventional SVPWM algorithm by distributing the pulse patterns randomly. The DZRCDPWM provides better performance over the entire modulation index range for induction motor drive control with reduced acoustic noise.
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.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
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 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.
Performance Improvement of Multi Level Inverter fed Vector Controlled Inducti...IJPEDS-IAES
In this paper, the analysis of space vector based multi level inverter (MLI) fed vector controlled induction motor drive for a low speed operation is presented. The performance of indirect field oriented controlled induction motor drive (IMD) is poor with two-level inverter for low speed operations (LSO). The reduction in performance and peak value of torque are mainly due to the non-linearity caused by stator voltage drop and inverter. Hence the performance factors of induction motor drive are analyzed with the multi level inverters under different operating conditions. In this approach, the steady state ripple content in the current and torque waveforms are reduced and that to ripple content of torque is reduced from 0.15 to 0.05 under steady state with five-level inverter. When there is a step change in the load torque, the momentary decrease in speed with five-level inverter is less when compared two and three-level inverters and the speed response reaches the reference value very quickly with five-level inverter during steady state and transient periods. So the overall performance of drive is improved with five- level inverter when compared to two-level and three- level inverters under low speed operations.
This document summarizes a paper that models and simulates a switched reluctance motor (SRM) to minimize torque ripple through different converter topologies and control strategies. The paper develops a mathematical model of a 6/4 SRM in Matlab/Simulink. It simulates the motor with asymmetric, Miller, and modified Miller converters. Torque ripple is evaluated using power spectrum density analysis. The modified Miller converter shows better performance in minimizing torque ripple compared to the other topologies. The document concludes the modified Miller converter combined with closed-loop control can effectively reduce torque ripple in SRM for high-speed applications.
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.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
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 an experimental study on the use of neem methyl esters as biodiesel in a compression ignition engine. Neem oil was transesterified to produce biodiesel, which was then blended with diesel in ratios of 10%, 20%, and 30% by volume. The blends were tested in a single cylinder diesel engine and performance and emission characteristics were analyzed at varying loads. Results showed that the B20 blend performed better than diesel with lower emissions. Higher blend ratios like B30 saw decreased performance due to higher viscosity negatively impacting combustion. Overall, the study demonstrated the potential of neem biodiesel to replace a portion of diesel fuel.
This document summarizes a research paper that proposes a new routing protocol called U-LEACH for wireless sensor networks. U-LEACH aims to prolong the lifetime of sensor networks by uniformly distributing cluster head selection throughout the network, unlike the original LEACH protocol. It describes how LEACH works and its limitations in ensuring uniform cluster head distribution. The proposed U-LEACH protocol incorporates a Uniform Distribution Technique to select cluster heads in a way that ensures each sensor node is within transmission range of a cluster head, extending the overall network lifetime.
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 speech encryption system that aims to enhance security. It uses chaotic maps to generate a polynomial, which is then used to generate a large set of Kasami sequences. These sequences act as the encryption key. The speech signal is divided into segments and encrypted using AES-128 with the Kasami sequences. Evaluation using noise attacks shows the encrypted speech has high distortion measures, indicating low residual intelligibility and therefore high security. Linear prediction analysis, spectral distance, and cepstrum distance are used to analyze the original and encrypted speech signals. Results demonstrate the proposed system encrypts speech effectively while maintaining good audio quality.
The document summarizes advances in electronic nose technologies. It discusses the historical development of electronic noses from the 1950s to present. It describes the four main sensor types used in electronic noses: metal oxide semiconductors, metal oxide semiconductor field-effect transistors, conducting polymer sensors, and piezoelectric acoustic sensors. Each sensor type is explained in terms of its sensitive material, detection principle, and factors that influence selectivity and sensitivity. The document provides an overview of electronic nose technologies and the sensor types commonly used.
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 analyzes the dose linearity response of thermoluminescence in ternary mixed multiphased crystals of (KCl)x(KBr)y-x(KI)1-y that were prepared by melt method and irradiated with 15MV photon beams. Nine combinations of the crystals were irradiated at doses of 10, 50, 100, and 200Gy. Thermoluminescence glow curves were studied from 50-400°C at a heating rate of 3°C/sec. The (KCl)0.1(KBr)0.8(KI)0.1 composition showed a maximum TL output at 100Gy with a glow peak around 85°C
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 a hybrid multilevel converter topology combining a neutral point clamped (NPC) converter with floating DC-link cascaded H-bridge converters. The NPC provides the active power while the H-bridges operate as series active filters to improve the voltage waveform quality by handling reactive power. This reduces the need for large passive filters. The document outlines two design challenges: determining the lowest H-bridge DC-link voltage to achieve adequate harmonic compensation, and developing a control algorithm to regulate the floating DC-link voltages at this level. Experimental results are provided to validate the proposed modulation technique and improvement in output waveform quality.
The document discusses peak-to-average power ratio (PAPR) reduction techniques for orthogonal frequency division multiplexing (OFDM) systems. It analyzes the PAPR of discrete Hartley transform (DHT) precoded OFDM and compares it to discrete Fourier transform (DFT) precoded, Walsh-Hadamard transform (WHT) precoded, selected mapping (SLM) based, and conventional OFDM systems. Simulation results show that the WHT precoded OFDM system has the highest PAPR, while the DFT precoded OFDM system achieves zero PAPR. The document concludes that DFT precoding is the most effective technique for PAPR reduction analyzed.
This document discusses weak isomorphism and isomorphism between fuzzy graphs. Some key points:
1. Weak isomorphism preserves the weights of nodes but not necessarily the weights of edges, while isomorphism preserves weights of both nodes and edges.
2. If two fuzzy graphs are isomorphic, they have the same order (number of nodes) and size (sum of edge weights).
3. Isomorphism between fuzzy graphs is proved to be an equivalence relation as it is reflexive, symmetric and transitive.
4. Weak isomorphism is proved to be a partial order relation as it satisfies reflexivity, anti-symmetry and transitivity.
5. Some properties of self-complement
The document summarizes a research paper that proposes a low density parity check (LDPC) algorithm for insertion/deletion channels. It begins by providing background on LDPC codes and how they are finding increasing use for reliable information transfer over bandwidth-constrained links with noise. It then describes the specific system model of a concatenated coding scheme using an outer error correcting code and inner marker code. The document analyzes the achievable transmission rates using this scheme through both bit-level and symbol-level maximum a posteriori probability (MAP) detection algorithms. It finds that the symbol-level approach confirms an advantage over codes optimized for additive white Gaussian noise channels.
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 that analyzes the costs of alternative energy sources for powering a house in Gwalior, India. The authors conducted an energy audit of the house to determine its total energy consumption. They then analyzed the costs and feasibility of using solar panels and inverters as alternative energy sources. The results provided guidance on using methods like selective loading to reduce energy costs by powering parts of the house with these alternative sources. In conclusion, the study evaluated alternative energy options for the house to help address issues with India's unreliable electricity supply.
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 discusses the design and CFD simulation of an annular combustion chamber for a 20 kW gas turbine engine using kerosene as fuel. It outlines the design process which involved evaluating reference area based on aerodynamic and chemical considerations. The aerodynamic design aims for ideal constant pressure combustion while the chemical design allows for efficient combustion. CFD simulation was then carried out using ANSYS CFX to analyze temperature distribution within the combustion chamber.
O documento descreve um Termo de Ajuste de Gestão firmado entre o Tribunal de Contas de Pernambuco e a Prefeitura Municipal de Limoeiro para que esta disponibilizasse informações públicas em seu site conforme exigido por lei. Após descumprimento dos prazos pelo município, o Tribunal constatou que as informações ainda não estavam disponíveis on-line, caracterizando o não cumprimento do termo.
O documento discute as fontes alternativas de energia no Brasil, incluindo energias eólica, solar, geotérmica, maremotriz e biomassa. Ele descreve as vantagens dessas fontes, como serem renováveis e menos poluentes, e também problemas como altos custos iniciais. O documento também analisa a matriz energética brasileira e seu potencial para fontes alternativas.
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 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 corresponding to the rotor flux and torque. A model reference adaptive system is proposed for sensorless speed estimation, where the speed estimate is adapted by comparing outputs of an adjustable model and reference model. Simulation results show the sensorless control approach can accurately estimate speed with good tracking performance.
A robust rf mras based speed estimator using neural network as a reference mo...Alexander Decker
This document summarizes a research paper that proposes a robust speed estimator for sensorless vector controlled induction motor drives. The authors develop a single neuron cascaded neural network model trained on input/output data to estimate rotor flux. This neural network model replaces the conventional voltage model in rotor flux-based model reference adaptive system (RF-MRAS) speed estimation. By using a neural network reference model, the proposed RF-MRAS speed estimator is robust to variations in stator resistance and does not require a separate online resistance estimator. Simulation results demonstrate the performance of the proposed robust RF-MRAS speed estimator works over a wide speed range including zero speed, and is more robust than the conventional RF-MRAS approach.
A New QEA Based High Performance Sensorless Control of IM DriveIDES Editor
Quantum Evolutionary Algorithm (QEA) based
proportional-integral (PI) controller tuning is used for getting
fast speed response induction motor (IM) drive. A high
performance simple sensorless control of induction motor
drive is also presented in this paper. The control principle is
based on direct torque control (DTC) with space vector
modulation (SVM) technique. The SVM reduces the torque
and flux ripples and improve steady state performance. A
correlated real time recurrent learning (CRTRL) algorithm
based on recurrent neural network (RNN) is used to estimate
rotor flux which eliminates rotor position sensor. A simple
speed estimator for the induction motor is proposed to make
the controller cost effective and speed sensorless. The proposed
control methodologies and simulation results are given and
discussed.
This document summarizes a research paper that proposes a Model Reference Adaptive Controller (MRAC) for online estimation of rotor time constant and speed for indirect field oriented control of an induction motor drive. The MRAC design is based on reactive power concepts and consists of a reference model that is independent of slip speed and an adjustable model that depends on slip speed. The difference between the instantaneous reactive power computed by the reference model and the steady-state reactive power computed by the adjustable model is used as an error signal for an adaptation mechanism to estimate the slip speed and rotor resistance. Simulation results show the proposed MRAC approach can accurately estimate rotor time constant and speed.
Recently of the main topic of research is the sensorless vector control of induction motor drive, In this paper presents the predictive model reference adaptive system (PMRAS) rotor speed observer, This observer developed from the classical MRAS rotor flux scheme associated with predictive adaptation mechanism designed from the Finite Control Set Model Predictive Control (FCS–MPC) by using a search optimization algorithm for calculate the rotor position which guarantee a minimum speed tuning error signal at each sampling period. The effectiveness of the proposed observer proved with the simulation results, show high dynamic performance speed and position observed in sensorless vector control process at low and zero speed as well robustness against motor parameter variation with different loading conditions.
IRJET- Self-Tuning PID Controller with Genetic Algorithm Based Sliding Mo...IRJET Journal
This document presents a self-tuning PID controller with a genetic algorithm for sensorless induction motor drives. A model reference adaptive system estimator is proposed that uses a sliding mode technique for robustness. The estimator reduces chattering while maintaining sliding mode properties. Additionally, an auxiliary variable is used to improve stability in regenerating mode operation. Simulation results demonstrate the performance of the proposed estimator for speed estimation during rapid speed reversal and in regenerating mode. Parameter estimation is also achieved using adaptive mechanisms to estimate rotor resistance and mutual inductance.
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.
Dynamic Performance of Distance Relayson Series Compensated Transmission Line...Premier Publishers
Series compensation is installed in power system networks to increase power transfer capacity, improve the system stability, reduce system losses, improve voltage regulation and for achieving flexible power flow control. Distance relays are widely used as main or backup protection of transmission lines including series-compensated transmission lines. The performance of conventional distance relays is affected by series capacitors and cause certain protection issues. This paper briefly discusses the problems like voltage inversion, current inversion, overreach and under reach during the fault conditions specific to series compensated lines. The behavior of capacitor protection techniques is discussed with simulations performed using Real Time Digital Simulator (RTDS) simulator for a typical 400 kV system having series compensation. The analysis is based on Transmission Line fault simulations, internal and external to the 400-transmission line where the Fixed Series Compensation (FSC)is installed.
This document summarizes a research paper on sensorless speed control of a permanent magnet synchronous motor (PMSM) using direct torque control (DTC) with a model reference adaptive system (MRAS). It first describes the structure and equations of a PMSM and provides an overview of DTC. It then introduces MRAS for sensorless speed estimation. Simulation results using MATLAB show that the proposed DTC method with MRAS provides precise estimated speed, fast torque response, and good dynamic performance under sudden load changes.
MODELLING AND IMPLEMENTATION OF AN IMPROVED DSVM SCHEME FOR PMSM DTCpaperpublications3
This document discusses modelling and implementing an improved direct self control (DSC) scheme for permanent magnet synchronous motors (PMSMs) using discrete space vector modulation (DSVM). It begins with an overview of field oriented control and direct torque control techniques for PMSMs. It then presents the PMSM model and basic direct torque control scheme. Issues with the basic DTC scheme like torque and flux ripples are discussed. The document reviews the existing DSVM DTC technique and proposes a new DSVM DTC scheme for PMSMs that takes motor speed and torque/flux errors into account. Comparisons of performance and switching losses between basic DTC and improved DSVM DTC are made through simulation and experiments.
Adaptive control of saturated induction motor with uncertain load torqueAyyarao T S L V
1) The document reviews an adaptive control method for induction motors with uncertain load torque and magnetic saturation.
2) A nonlinear adaptive controller is designed using a field oriented control approach. The controller estimates the unknown time-varying load torque through online identification.
3) Once the load torque is identified, the control decouples regulating rotor speed and flux amplitude to improve efficiency without affecting speed regulation. Adaptation laws are developed to track the load torque and regulate the motor's speed and flux.
Performance, Modelling & Simulation of Frequency Relays for Distributed Gener...Niraj Solanki
The document discusses modeling and simulation of an adaptive frequency relay for distributed generation protection. It presents:
1) Performance curves showing the islanding detection capability of frequency relays depends on active power imbalance.
2) A model for an adaptive frequency relay that can automatically change settings based on whether the microgrid is connected to or isolated from the main grid.
3) Simulation results demonstrating the relay detecting over and under frequency conditions within allowed limits for both grid-connected and island modes of operation.
Particle swarm optimization-based stator resistance observer for speed sensor...IJECEIAES
This paper presents a different technique for the online stator resistance estimation using a particle swarm optimization (PSO) based algorithm for rotor flux oriented control schemes of induction motor drives without a rotor speed sensor. First, a conventional proportional-integral controller-based stator resistance estimation technique is used for a speed sensorless control scheme with two different model reference adaptive system (MRAS) concepts. Finally, a novel method for the stator resistance estimation based on the PSO algorithm is presented for the two MRAS-type observers. Simulation results in the Matlab/Simulink environment show good adaptability of the proposed estimation model while the stator resistance is varied to 200% of the nominal value. The results also confirm more accurate stator resistance and rotor speed estimation in comparison with the conventional technique.
The document presents a method for sensorless speed control of a permanent magnet synchronous motor (PMSM) using a model reference adaptive system (MRAS) with a multilayer perceptron (MLP) neural network. The MRAS uses the PMSM model as the reference model and a current model as the adjustable model. Error signals from comparing the models are fed into the MLP network. Particle swarm optimization (PSO) is used to optimize the MLP weights and biases to minimize errors. Simulation results show the proposed MLP-PSO method achieves better performance than a PI controller in terms of rise time, settling time, overshoot, and root mean square error for various speed and load conditions.
Position sensorless vector control of pmsm for electrical household applicanceswarluck88
This document proposes a position sensorless vector control method for permanent magnet synchronous motors (PMSMs) suitable for electrical household appliance motor drives. It presents a simple position estimation equation and describes its derivation. It also proposes a simplified vector control method that does not require an automatic speed or current regulator but can achieve similar drive performance to conventional vector control under steady state conditions. Simulation and experimental results on a battery-driven cordless vacuum cleaner motor demonstrate the effectiveness of the proposed high-speed sensorless drive system using a typical low-cost microcontroller.
This document summarizes a research paper on modeling DC-DC converters with high frequencies using state space analysis. The paper presents an approach to modeling that avoids assuming constant current ripples, allowing for a better representation at high frequencies. State space averaging is commonly used to model PWM DC-DC converters but has limitations. The presented approach generalizes state space averaging to account for harmonics' effects, transforming time-varying models into time-invariant linear models. Equations for the state space model of a buck converter are provided both when operating and when turned off, and the average state model is derived. The goal is to improve performance for load and input variations through implicit feedforward compensation.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Induction motor harmonic reduction using space vector modulation algorithmjournalBEEI
The vector control was proposed as an alternative to the scalar control for AC machines control. Vector control provide high operation performance in steady state and transient operation. However, the variable switching frequency of vector control causes high flux and torque ripples which lead to an acoustical noise and degrade the performance of the control scheme. The insertion of the space vector modulation was a very useful solution to reduce the high ripples level inspite of its complexity. Numerical simulation results obtained in MATLAB/Simulink show the good dynamic performance of the proposed vector control technique and the effectiveness of the proposed sensorless strategy in the presence of the sudden load torque basing on the integral backstepping approach capabilities on instant perturbation rejection.
Keywords
Accurate modeling of cables is important to study the behavior of high frequency disturbances in power converter systems. This paper reviews and compares two popular methodologies to model energy cables – an improved per unit length parameters based model and a Laplace SPICE element based model. The two models presented take into account the frequency dependence of the parameters of the cable. A ladder network is used for this purpose in the per unit length based model. The Laplace SPICE element model is generated from from a rational function approximation for the admittance parameters that are frequency dependant. The rational function approximation is obtained using a well known vector fitting algorithm. The time and frequency domain solutions of a two wire energy cable, obtained from the two models, agree well.
1. L.A.Abraham Arunchand, K.Sudharshan Reddy / International Journal of Engineering Research and
Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 4, July-August 2012, pp.087-092
An Artificial-Intelligence Based Induction Motor Speed control and
Estimation using conventional MRAS with dynamic reference modal
L.A.Abraham Arunchand*, K.Sudharshan Reddy**,
*(PG student, Department of Electrical & Electronics Engineering, Sri Venkatesa Perumal College of Engineering &
Technology)
** (Assistant professor, Department of Electrical & Electronics Engineering, Sri Venkatesa Perumal College of Engineering &
Technology)
Abstract− The Model Reference Adaptive System based model. However, both the conventional MRAS and
(MRAS) is probably the most widely applied speed sensor AI-based MRAS scheme are easily affected by machine
less drive control scheme. This paper gives induction motor parameter variations, which happen during practical
speed estimation using conventional MRAS and AI-based operation. In this case, an online stator resistance estimator
MRAS with Stator Resistance Compensation methods. A is applied to the AI-based MRAS scheme which makes the
conventional mathematical model based MRAS speed whole scheme more robust during computer simulation and
estimation scheme can give a relatively precise speed could possible make the scheme usable for practical
estimation result, but errors will occur during low frequency operation. The comparison of schemes presented here is
operation. Furthermore, it is also very sensitive to machine felt to be valuable since much of the literature presents
parameter variations. However, an AI-based MRAS-based results for the novel approach alone.
system with a Stator Resistance Compensation model can
improve the speed estimation accuracy and is relatively II. SPEED ESTIMATION USING
robust to parameter variations even at an extremely low CONVENTIONAL MODAL REFERENCE
frequency. Simulation results using a validated machine ADAPTIVE SYSTEM
model are used to demonstrate the improved behavior and
also controlling the speed of motor by using space vector In MRAS, there are two models, which work parallel to
pulse width modulation (SVPWM) with estimated speed estimate flux-linkage of induction motor, first model name
taking as feedback. reference, and input is current and voltage, the output flux
linkage of this model is to be used fiducial variable. The
Index Terms− Dynamic Reference Model, Model second model is adaptive, input of it is current and rotor
Reference Adaptive System (MRAS), Neural Networks, speed, output flux-linkage of this model is been adjusted
Induction Motor Control. continuously in order that the error between those two
models is turn to zero by adjusting the input of adaptive
I. INTRODUCTION model through PI controller. The expressions for the rotor
flux linkages in the stationary reference frame can be
Much effort has been devoted to speed-sensor less obtained by using the stator voltage equations of the
induction machine drive schemes, with Model Reference induction machine (in the stationary reference frame).
Adaptive System (MRAS) being the most popular. In a These give (1) and (2), which are now rearranged for the
conventional mathematical-model-based MRAS, some rotor flux linkages:
state variables are estimated in a reference model, (e.g.
rotor flux linkage components, ψrd, ψrq, or back e.m.f. L L2 m
L
V r
ds
Rs ids dt ( Ls )isd
components, ed, eq,etc.) of the induction machine dr
m
Lr (1)
L V
obtained by using measured quantities, (e.g. stator currents L2 m
and perhaps voltages). These reference model components
r
qs
Rs iqs dt ( Ls )isQ (2)
are then compared with state Variables estimated using an L
qr
m
Lr
adaptive model. The difference between these state
variables is then used in an adaptation mechanism, which, These two equations represent a so-called stator voltage
for example, outputs the estimated value of the rotor speed model, which does not contain the rotor speed and is
(ωr) and adjusts the adaptive model until satisfactory therefore a reference model. However, when the rotor
performance is obtained Nevertheless, greater accuracy voltage equations of the induction machine are expressed
and robustness can be achieved, if the mathematical model in the stationary reference frame, they contain the rotor
is not used at all and instead, an AI-based non-linear fluxes and the speed as well. These are the equations of the
adaptive model is employed. It is then also possible to adaptive model:
eliminate the need of the separate PI controller, since this
can be integrated into the tuning mechanism of the AI-
87 | P a g e
2. L.A.Abraham Arunchand, K.Sudharshan Reddy / International Journal of Engineering Research and
Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 4, July-August 2012, pp.087-092
ˆ 1
L i Tˆ ˆ dt
T
m ds
r r (3) different types of speed tuning signals. It is believed that
dr qr dr
r some of these solutions can give high accuracy and are
relatively robust to parameter variations even at extremely
ˆ 1
L i Tˆ ˆ dt low stator frequency. One specific implementation of the
T
m qs
r r (4) ANN-based MRAS speed estimator system which is
qr dr qr
r
popular in academic work, as shown in Fig. 2, which is
similar to the conventional MRAS system. In this new
The reference and adaptive models are used to estimate the model, the adaptive model is replaced by a simple two
rotor flux linkages and the angular difference of the layer neural network, which enables the whole system with
outputs of the two estimators fast response and better accuracy than the conventional
w Im( r , * r ) rq rd rd rq is
ˆ ˆ ˆ used as the MRAS
.
speed tuning signal. Adaptation mechanism is the PI
controller to turn the error state of reference and adaptive
model to zero by adjusting the input of adaptive model,
which variable is the rotor speed.
Fig.2 MRAS-based rotor speed estimator containing
a two layer ANN
Fig.1 MRAS-based rotor speed observer using rotor
IV. MRAS based Two Layer ANN speed estimator
flux with dynamic reference modal
Linkages for the speed tuning signal
Compared to the conventional MRAS based rotor
By the time error state equivalent to zero the system give speed estimator containing a Two layer ANN could give
the estimate speed equivalent to actual speed .The more accurate estimation result and relatively robust to
estimated speed can be expressed as (5) parameter variations. The two layer ANN replaces the
adjustable model and adaptive mechanism in the
r k p w ki w dt (5) conventional MRAS, but the reference model is still
necessary for estimation the rotor flux which is used as
III. ARTIFICIAL INTELLIGENCE-BASED speed tuning signal. Several machine parameters are used
to build the conventional reference model, such as stator
MODEL REFERENCE ADAPTIVE
resistance (Rs) and stator reluctance (Ls). These parameters
SYSTEM may change during the different periods of motor
operating. The values of these parameters are fixed in the
The MRAS-based schemes described in the previous reference model. So the ANN speed estimator is still
section contain a reference model and an adaptive model. sensitive to parameter variations especially during the
However, greater accuracy and robustness can be achieved motor low speed running period. To solve this problem and
if the mathematical model is partially replaced by a neural make this scheme more independent to the machine
network. It is then also possible to eliminate the need of the parameters, a stator resistance estimator is built in the new
separate PI controller, since this can be integrated into the reference model, in which the stator resistance Rs value
tuning mechanism of the neural network-based model. The could be estimated online. Fig. 3 shows the total scheme of
neural network-based model can take various forms: it can neural network based MRAS with a dynamic reference
be an artificial neural network (ANN) or a fuzzy neural model.
network etc. and there is also the possibility of using
88 | P a g e
3. L.A.Abraham Arunchand, K.Sudharshan Reddy / International Journal of Engineering Research and
Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 4, July-August 2012, pp.087-092
In this new system, both the reference model and adaptive ANN, the sampled data forms of equations (3) and (4) are
model of the conventional MRAS system are modified for considered. By using the backward difference method, the
better performance. The whole system can be divided into sampled data forms of the equations for the rotor flux
two main parts, the dynamic reference model part and the linkages can be written as (8) and (9), where T is the
neural network part. The dynamic reference part consists sampling time.
of the dynamic reference model derived from equations (1)
and (2), in which the stator resistance Rs is replaced by the rd (k ) rd (k 1) rd(k 1) wr rq (k 1) Lm
isd (k 1)
online estimated value Rs coming from equation (6) and T Tr T Tr
(7), (8)
ˆ Ki
Rs ( K p )eR s (6)
P
rq (k ) rq (k 1) (k 1) wr rd (k 1) Lm
rRs isD ( rd rd ) isQ ( rq rq )
ˆ ˆ rq isq (k 1)
(7) T Tr T Tr
The neural network part contains a simple two-layer neural (9)
network, with only an input layer and an output layer.
Thus the rotor flux linkages at the kth sampling instant can
Adjustable and constant weights are built in the neural
be obtained from the previous (k-1)th values as
network, and the adjustable weights are proportional to the
rd (k ) rd (k 1)(1 T / Tr ) rT rq (k 1) ( LmT / Tr )isd (k 1)
rotor speed.
(10)
rq (k ) rq (k 1)(1 T / Tr ) rT rd (k 1) ( LmT / Tr )isQ (k 1)
(11)
Introducing the following weights are given:
w1 1 c
w2 r cTr r T (12)
w3 cLm
It can be seen that w1 and w3 are constant weights, but w2
Fig.3 MRAS based ANN speed estimator with dynamic is a variable weight and is proportional to the speed. Thus
reference model. Equations (10) and (11) take the following forms:
The adjustable weights are changed by using the error rd (k ) w1 rd (k 1) w2 rq (k 1) w3isD (k 1)
between the outputs of the reference model and the (13)
adjustable model, since any mismatch between the actual rq (k ) w1 rq (k 1) w2 rd (k 1) w3isQ (k 1)
rotor speed and the estimated rotor speed results in an error
between the outputs of the reference and adaptive (14)
estimators. To obtain the required weight adjustments in the
These equations can be visualized by the very simple two The neural network is training by the back propagation
layer ANN shown in Fig. 4. method; the estimated rotor speed can be obtained from:
w2 (k )
r (k ) r (k 1) w2 (k 1)
T T
r (k 1) {[ rd (k ) rd (k )] rq (k 1) [ rq (k ) rq (k )] rd (k 1)} w2 (k 1)
T T
(15)
Where η is the learning rate and α is a positive constant
called the momentum constant. The inclusion of the
momentum term into the weight adjustment mechanism can
significantly increase the convergence, which is extremely
useful when the ANN shown in Fig. 4 is used to estimate in
real time the speed of the induction machine.
Fig. 4 Neural network representation for estimated rotor flux
linkages
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4. L.A.Abraham Arunchand, K.Sudharshan Reddy / International Journal of Engineering Research and
Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 4, July-August 2012, pp.087-092
V.SPEED CONTROL BY USING SPACE
VECTOR PULSE WIDTH MODULATION
(SVPWM):
By the above process we can estimate the speed of induction
motor which is actual speed of rotor. If the estimated speed is
not equal to reference speed to operate, we can run the motor
as our requirement by using estimated speed as a feed back
and SVPWM. By comparing the reference speed and
estimated speed, an error will produce which is send to PI
controller to produce the required iq i.e. q-axis current of
induction motor. This q-axis current is again compared with
actual (steady state) iq to find out the error, which is helpful
Fig. 6 Speed Estimation using Two-layer ANN MRAS
to estimate the require amount of voltage, which is need to
space vector pulse width modulation. In SVPWM the Further simulation has been carried out with changed stator
required switching pulses will give to voltage source inverter resistance to test how much the parameter changing would
(VSI) to reduce the error between ( iq , iq ). In VSI the affect the speed estimation results.
required switching operations ( as switching pulses giving
from SVPWM) will done to reduce the error between
estimated speed and reference (required) speed and produce
voltages Va,Vb,Vc to minimize the error.
VI.SIMULATION RESULTS
To compare the conventional MRAS and the AI-based
MRAS with dynamic reference model, simulations are
established by using Matlab-Simulink software, based on
the standard well established validated 2-axis machine
model [6]. Speed estimation results using conventional
MRAS and neural network based MRAS are shown in Fig.
5 and Fig. 6 respectively. These results assume the machine
parameters are correctly measured and unchanged during Fig.7 Speed estimation by using Conventional MRAS (with
operation. Both of the two schemes can give good speed Stator resistance Rs changed 2%)
tracking results.
Fig. 8 Speed Estimation using Two-layer ANN MRAS
Fig. 5 Speed estimation using Conventional MRAS (with Stator resistance Rs changed 2%)
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5. L.A.Abraham Arunchand, K.Sudharshan Reddy / International Journal of Engineering Research and
Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 4, July-August 2012, pp.087-092
when the parameters are precisely measured and do not change
during operation. The MRAS with adaptive model replaced by
the two-layer neural network can slightly improve the
performance when working in the same situation. But both
schemes can still be easily affected by parameters variations,
which do occur during practical operation. By introducing the
stator resistance online estimator, the performance is much
improved which should enable the scheme usable for practical
operation.
VI I.CONCLISION
The main objective of this paper is to compare
conventional MRAS and AI-based MRAS for induction motor
speed sensor less speed estimation. The conventional MRAS
can give good speed estimation in most of the operation
period, but errors will occur during low frequency operation
Fig. 9 Speed Estimation using Two-layer MRAS with mainly caused by the machine parameter variations. An AI-
Dynamic reference model based MRAS system can give improved accuracy and
bypasses the PI controller tuning problems. The simple
structure of the two-layer neural network shown in Fig. 4
yields a speed estimation system working online with a fast
response. Also the simple two-layer neural network does not
require a separate learning stage, since the learning takes
place during the on-line speed estimation process. This is
mainly due to the fact that the development time of such an
estimator is short and the estimator can be made robust to
parameter variations and noise. Furthermore, in contrast to
most conventional schemes, it can avoid the direct use of a
speed-dependent mathematical model of the machine.
However, the Two-layer neural network MRAS lies more in
the realm of adaptive control then neural networks. The speed
value is not obtained at the output, but as one of the weights.
Moreover, only one weight is adjusted in the training.
Therefore, it would still be sensitive to parameter variations
and system noise. In the new approach, an online stator
Fig. 10 Estimated Rs in the dynamic reference model resistance estimator is used to compensate the parameter
variations. From the comparison of the computer simulation
In Fig. 7 and Fig. 8, simulations are carried out with the stator results, it is obvious that this new approach makes the whole
resistance changed by a small amount, 2%. Obviously, both scheme more robust to parameter variations, which also gives
schemes are still sensitive to parameter variations. A final the possibility of practical use of the neural network based
simulation for AI-based MRAS with the dynamic reference MRAS scheme. The stator resistance estimator is working
model is shown in Fig. 9. The online estimated stator resistance under adaptive mechanism (PI controller). Further study
is displayed in Fig. 10. From the simulation result in Fig. 9, the could be carried out for replace the PI controller with another
effect caused by the stator resistance variation has been simple neural network which could also estimate more
considerably improved. Comparing all the above simulation machine parameters.
results shows that the conventional MRAS scheme works well
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6. L.A.Abraham Arunchand, K.Sudharshan Reddy / International Journal of Engineering Research and
Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 4, July-August 2012, pp.087-092
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