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.
Updated field oriented control of induction motor.pptxMohit Sharma
It is a simulation work project done on a 5hp,440V/5A and 1440rpm Induction motor.It explains the control of induction motor using matlab-simulink algorithm by PI control as well as Fuzzy logic control.
Simulation of Direct Torque Control of Induction motor using Space Vector Mo...IJMER
This paper presents simulation of Direct Torque Control (DTC) of Induction Motor using Space
Vector Modulation (SVM). Direct Torque Control is a control strategy used for high performance torque
control of Induction Motor. This SVM based DTC technique reduces torque ripple and improves torque
response. The performance is explained using simulation in MATLAB environment. Result of the
simulation done in the paper shows improvement in flux and torque. These results verifies the merits of
DTC- SVM over conventional Direct Torque Control technique.
Indirect Vector Control of Induction Motor Using Pi Speed Controller and Neur...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
This ppt gives a small introduction to vector speed control of induction motor.
In my uploads another pdf is there which completely explains about vector control method
Speed Control of Induction Motor using FOC MethodIJERA Editor
An increasing number of applications in high performing electrical drive systems use nowadays, squirrel-cage induction motors. This paper describes a simplified method for the speed control of a three phase AC drive using Proportional-Integral controller. The simulation results show that the step response of the model is very fast, steady and able to work in four quadrants, and robustness and high performance is achieved.
Updated field oriented control of induction motor.pptxMohit Sharma
It is a simulation work project done on a 5hp,440V/5A and 1440rpm Induction motor.It explains the control of induction motor using matlab-simulink algorithm by PI control as well as Fuzzy logic control.
Simulation of Direct Torque Control of Induction motor using Space Vector Mo...IJMER
This paper presents simulation of Direct Torque Control (DTC) of Induction Motor using Space
Vector Modulation (SVM). Direct Torque Control is a control strategy used for high performance torque
control of Induction Motor. This SVM based DTC technique reduces torque ripple and improves torque
response. The performance is explained using simulation in MATLAB environment. Result of the
simulation done in the paper shows improvement in flux and torque. These results verifies the merits of
DTC- SVM over conventional Direct Torque Control technique.
Indirect Vector Control of Induction Motor Using Pi Speed Controller and Neur...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
This ppt gives a small introduction to vector speed control of induction motor.
In my uploads another pdf is there which completely explains about vector control method
Speed Control of Induction Motor using FOC MethodIJERA Editor
An increasing number of applications in high performing electrical drive systems use nowadays, squirrel-cage induction motors. This paper describes a simplified method for the speed control of a three phase AC drive using Proportional-Integral controller. The simulation results show that the step response of the model is very fast, steady and able to work in four quadrants, and robustness and high performance is achieved.
Speed Sensorless Vector Control of Induction Motor Drive with PI and Fuzzy Co...IJPEDS-IAES
This paper directed the speed-sensorless vector control of induction motor drive with PI and fuzzy controllers. Natural observer with fourth order state space model is employed to estimate the speed and rotor fluxes of the induction motor. The formation of the natural observer is similar to and as well as its attribute is identical to the induction motor. Load torque adaptation is provided to estimate the torque and rotor speed is estimated from the load torque, rotor fluxes and stator currents. There is no direct feedback in natural observer and also observer gain matrix is absent. Both the induction motor and the observer are characterized by state space model. Simple fuzzy logic controller and conventional PI controllers are used to control the speed of the induction motor in closed loop. MATLAB simulations are made with PI and fuzzy controllers and the performance of fuzzy controller is better than PI controller in view of torque ripples. The simulation results are obtained for various running conditions to exhibit the suitability of this method for sensorless vector control. Experimental results are provided for natual observer based sensorless vector control with conventional PI controller.
Novel Method of FOC to Speed Control in Three-Phase IM under Normal and Fault...IJPEDS-IAES
This paper proposes a novel method for speed control of three-phase
induction motor (IM) which can be used for both healthy three-phase IM and
three-phase IM under open-phase fault. The proposed fault-tolerant control
system is derived from conventional field-oriented control (FOC) algorithm
with minor changes on it. The presented drive system is based on using an
appropriate transformation matrix for the stator current variables. The
presented method in this paper can be also used for speed control of singlephase
IMs with two windings. The feasibility of the proposed strategy is
verified by simulation results.
Speed Control System of Induction Motor by using Direct Torque Control Method...ijtsrd
Escalator is useful and act in the important part to carry passengers to the targeted floors of building. Every escalator must be driven by its own motor and this motor speed must be controled. To drive escalator with a constant speed, direct torque control technique is used to drive three phase squirrel cage induction motor. In this paper, the development of speed control system for three phase squirrel cage induction motor using a direct torque control method is presented and simulation for proposed system is done with the help of MATLAB SIMULINK. Soe Sandar Aung | Thet Naing Htun "Speed Control System of Induction Motor by using Direct Torque Control Method used in Escalator" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd27903.pdfPaper URL: https://www.ijtsrd.com/engineering/electrical-engineering/27903/speed-control-system-of-induction-motor-by-using-direct-torque-control-method-used-in-escalator/soe-sandar-aung
Speed Sensorless Vector Control of Unbalanced Three-Phase Induction Motor wit...IAES-IJPEDS
This paper presents a technique for speed sensorless Rotor Flux Oriented Control (RFOC) of 3-phase Induction Motor (IM) under open-phase fault (unbalanced or faulty IM). The presented RFOC strategy is based on rotational transformation. An adaptive sliding mode control system with an adaptive switching gain is proposed instead of the speed PI controller. Using an adaptive sliding mode control causes the proposed speed sensorless RFOC drive system to become insensitive to uncertainties such as load disturbances and parameter variations. Moreover, with adaptation of the sliding switching gain, calculation of the system uncertainties upper bound is not needed. Finally, simulation results have been presented to confirm the good performance of the proposed method.
Matrix Converter based Direct Torque Control of Induction MotorNeehar NLN
This topic falls under the area of speed control of induction motor. The using of advanced power electronic converters provides better response. In this case, a AC/AC converter is used to control the induction motor.
Review of Improved Direct Torque Control Methodologies for Induction Motor Dr...AM Publications
ecoupled control of induction motor drives is possible using Direct Torque Control (DTC) method which
is very simple control strategy compared to field oriented control. In this method direct torque control is achieved by
selecting suitable inverter switching voltage vector from a lookup table. But drawback of this method is that it
produces toque ripples. Also the switching frequency of inverter switches is not constant. Many methods have been
proposed to address these issues of DTC. This paper reviews various methodologies which are suggested to improve
performance of basic DTC induction motor drive.
Direct Torque Control (DTC) of Induction Motor drive has quick torque response without complex orientation transformation and inner loop current control. DTC has some drawbacks, such as the torque and flux ripple. The control scheme performance relies on the accurate selection of the switching voltage vector. This proposed simple structured neural network based new identification method for flux position estimation, sector selection and stator voltage vector selection for induction motors using direct torque control (DTC) method. The ANN based speed controller has been introduced to achieve good dynamic performance of induction motor drive. The Levenberg-Marquardt back-propagation technique has been used to train the neural network. Proposed simple structured network facilitates a short training and processing times. The stator flux is estimated by using the modified integration with amplitude limiter algorithms to overcome drawbacks of pure integrator. The conventional flux position estimator, sector selector and stator voltage vector selector based modified direct torque control (MDTC) scheme compared with the proposed scheme and the results are validated through both by simulation and experimentation.
SPEED AND TORQUE CONTROL OF AN INDUCTION MOTOR WITH ANN BASED DTCijics
Due to advantages such as fast dynamic response, simple and robust control structure, direct torque
control (DTC) is commonly used method in high performance control method for induction motors. Despite
mentioned advantages, there are some chronically disadvantages with this method like high torque and
current ripples, variable switching behaviour and control problems at low speed rates. On the other hand,
artificial neural network (ANN) based control algorithms are getting increasingly popular in recent years
due to their positive contribution to the system performance. The purpose of this paper is investigating of
the effects of ANN integrated DTC method on induction motor performance by numerical simulations. For
this purpose, two different ANN models have been designed, trained and implemented for the same DTC
model. The first ANN model was designed to select optimum inverter and the second model was designed to
use in the determination of the flux vector position. Matlab/Simulink model of the proposed ANN based
DTC method was created in order to compare with the conventional DTC and the proposed DTC methods.
The simulation studies proved that the induction motor torque ripples have been reduced remarkably with
the proposed method and this approach can be a good alternative to the conventional DTC method for
induction motor control.
V/F Control of Squirrel Cage Induction Motor Drives Without Flux or Torque Me...Waqas Tariq
Based on the popular constant volts per hertz principle, two improvement techniques are presented: keeping maximum torque constant or keeping magnetic flux constant. An open-loop inverter-three-phase squirrel-cage induction motor drive system that provides constant maximum torque or increased maximum torque and reduced slip speed at frequencies below the nominal frequency has been modeled, simulated and tested. Load performance analysis of the proposed system under different operation conditions was provided. These principles of operation are extended to the case of operation from variable frequency or variable voltage control method. Finally, the effects of the non-sinusoidal voltage and/or current wave shapes are covered. The results show that both suggested improvement techniques (constant torque or constant flux) improve the steady-state performance A.C. drive system with squirrel cage induction motors. The slip speed has been decreased and the starting torque and maximum torque have been increased, which means that the suggested control techniques can be used in drive systems with short time operating mode under light loads.
Speed Control of Induction Motor using Variable Frequency DriveSandeep Kaushal
Induction motor is constant speed motor at a particular frequency and consumes almost same power irrespective of load demand. Let's talk about two different load one is high load and other low load. AT low load motor is delivering the load with some current and thereby torque is maintained. If load goes high, to maintain the same speed and developed torqued, motor will draw extra current and will corresponds to more losses. If speed of motor is reduced corresponding too low load and is increased corresponding to high load, then substantial amount of power can be saved. And speed can be changed by changing the frequency of input supply.
Implementation scheme of the Direct Torque Control strategy to Four Switch T...IJMER
This paper proposes a novel direct torque control (DTC) strategy for induction motor (IM) drives
fed by a four switch three-phase inverter (FSTPI). The introduced strategy is based on the emulation of the
operation of the conventional six switch three-phase inverter (SSTPI). This has been achieved thanks to a
suitable combination of the four unbalanced voltage vectors intrinsically generated by the FSTPI, leading to
the synthesis of the six balanced voltage vectors of the SSTPI.
This approach has been adopted in the design of the vector selection table of the proposed DTC
strategy which considers a subdivision of the Clarke plane into six sectors. Simulation results have revealed
that, thanks to the proposed DTC strategy, FSTPI-fed IM drives exhibit interesting performance. These have
been experimentally validated and compared to the ones yielded by the Takahashi and the basic DTC
strategies dedicated to the SSTPI and to the FSTPI, respectively.
Speed Sensorless Vector Control of Induction Motor Drive with PI and Fuzzy Co...IJPEDS-IAES
This paper directed the speed-sensorless vector control of induction motor drive with PI and fuzzy controllers. Natural observer with fourth order state space model is employed to estimate the speed and rotor fluxes of the induction motor. The formation of the natural observer is similar to and as well as its attribute is identical to the induction motor. Load torque adaptation is provided to estimate the torque and rotor speed is estimated from the load torque, rotor fluxes and stator currents. There is no direct feedback in natural observer and also observer gain matrix is absent. Both the induction motor and the observer are characterized by state space model. Simple fuzzy logic controller and conventional PI controllers are used to control the speed of the induction motor in closed loop. MATLAB simulations are made with PI and fuzzy controllers and the performance of fuzzy controller is better than PI controller in view of torque ripples. The simulation results are obtained for various running conditions to exhibit the suitability of this method for sensorless vector control. Experimental results are provided for natual observer based sensorless vector control with conventional PI controller.
Novel Method of FOC to Speed Control in Three-Phase IM under Normal and Fault...IJPEDS-IAES
This paper proposes a novel method for speed control of three-phase
induction motor (IM) which can be used for both healthy three-phase IM and
three-phase IM under open-phase fault. The proposed fault-tolerant control
system is derived from conventional field-oriented control (FOC) algorithm
with minor changes on it. The presented drive system is based on using an
appropriate transformation matrix for the stator current variables. The
presented method in this paper can be also used for speed control of singlephase
IMs with two windings. The feasibility of the proposed strategy is
verified by simulation results.
Speed Control System of Induction Motor by using Direct Torque Control Method...ijtsrd
Escalator is useful and act in the important part to carry passengers to the targeted floors of building. Every escalator must be driven by its own motor and this motor speed must be controled. To drive escalator with a constant speed, direct torque control technique is used to drive three phase squirrel cage induction motor. In this paper, the development of speed control system for three phase squirrel cage induction motor using a direct torque control method is presented and simulation for proposed system is done with the help of MATLAB SIMULINK. Soe Sandar Aung | Thet Naing Htun "Speed Control System of Induction Motor by using Direct Torque Control Method used in Escalator" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd27903.pdfPaper URL: https://www.ijtsrd.com/engineering/electrical-engineering/27903/speed-control-system-of-induction-motor-by-using-direct-torque-control-method-used-in-escalator/soe-sandar-aung
Speed Sensorless Vector Control of Unbalanced Three-Phase Induction Motor wit...IAES-IJPEDS
This paper presents a technique for speed sensorless Rotor Flux Oriented Control (RFOC) of 3-phase Induction Motor (IM) under open-phase fault (unbalanced or faulty IM). The presented RFOC strategy is based on rotational transformation. An adaptive sliding mode control system with an adaptive switching gain is proposed instead of the speed PI controller. Using an adaptive sliding mode control causes the proposed speed sensorless RFOC drive system to become insensitive to uncertainties such as load disturbances and parameter variations. Moreover, with adaptation of the sliding switching gain, calculation of the system uncertainties upper bound is not needed. Finally, simulation results have been presented to confirm the good performance of the proposed method.
Matrix Converter based Direct Torque Control of Induction MotorNeehar NLN
This topic falls under the area of speed control of induction motor. The using of advanced power electronic converters provides better response. In this case, a AC/AC converter is used to control the induction motor.
Review of Improved Direct Torque Control Methodologies for Induction Motor Dr...AM Publications
ecoupled control of induction motor drives is possible using Direct Torque Control (DTC) method which
is very simple control strategy compared to field oriented control. In this method direct torque control is achieved by
selecting suitable inverter switching voltage vector from a lookup table. But drawback of this method is that it
produces toque ripples. Also the switching frequency of inverter switches is not constant. Many methods have been
proposed to address these issues of DTC. This paper reviews various methodologies which are suggested to improve
performance of basic DTC induction motor drive.
Direct Torque Control (DTC) of Induction Motor drive has quick torque response without complex orientation transformation and inner loop current control. DTC has some drawbacks, such as the torque and flux ripple. The control scheme performance relies on the accurate selection of the switching voltage vector. This proposed simple structured neural network based new identification method for flux position estimation, sector selection and stator voltage vector selection for induction motors using direct torque control (DTC) method. The ANN based speed controller has been introduced to achieve good dynamic performance of induction motor drive. The Levenberg-Marquardt back-propagation technique has been used to train the neural network. Proposed simple structured network facilitates a short training and processing times. The stator flux is estimated by using the modified integration with amplitude limiter algorithms to overcome drawbacks of pure integrator. The conventional flux position estimator, sector selector and stator voltage vector selector based modified direct torque control (MDTC) scheme compared with the proposed scheme and the results are validated through both by simulation and experimentation.
SPEED AND TORQUE CONTROL OF AN INDUCTION MOTOR WITH ANN BASED DTCijics
Due to advantages such as fast dynamic response, simple and robust control structure, direct torque
control (DTC) is commonly used method in high performance control method for induction motors. Despite
mentioned advantages, there are some chronically disadvantages with this method like high torque and
current ripples, variable switching behaviour and control problems at low speed rates. On the other hand,
artificial neural network (ANN) based control algorithms are getting increasingly popular in recent years
due to their positive contribution to the system performance. The purpose of this paper is investigating of
the effects of ANN integrated DTC method on induction motor performance by numerical simulations. For
this purpose, two different ANN models have been designed, trained and implemented for the same DTC
model. The first ANN model was designed to select optimum inverter and the second model was designed to
use in the determination of the flux vector position. Matlab/Simulink model of the proposed ANN based
DTC method was created in order to compare with the conventional DTC and the proposed DTC methods.
The simulation studies proved that the induction motor torque ripples have been reduced remarkably with
the proposed method and this approach can be a good alternative to the conventional DTC method for
induction motor control.
V/F Control of Squirrel Cage Induction Motor Drives Without Flux or Torque Me...Waqas Tariq
Based on the popular constant volts per hertz principle, two improvement techniques are presented: keeping maximum torque constant or keeping magnetic flux constant. An open-loop inverter-three-phase squirrel-cage induction motor drive system that provides constant maximum torque or increased maximum torque and reduced slip speed at frequencies below the nominal frequency has been modeled, simulated and tested. Load performance analysis of the proposed system under different operation conditions was provided. These principles of operation are extended to the case of operation from variable frequency or variable voltage control method. Finally, the effects of the non-sinusoidal voltage and/or current wave shapes are covered. The results show that both suggested improvement techniques (constant torque or constant flux) improve the steady-state performance A.C. drive system with squirrel cage induction motors. The slip speed has been decreased and the starting torque and maximum torque have been increased, which means that the suggested control techniques can be used in drive systems with short time operating mode under light loads.
Speed Control of Induction Motor using Variable Frequency DriveSandeep Kaushal
Induction motor is constant speed motor at a particular frequency and consumes almost same power irrespective of load demand. Let's talk about two different load one is high load and other low load. AT low load motor is delivering the load with some current and thereby torque is maintained. If load goes high, to maintain the same speed and developed torqued, motor will draw extra current and will corresponds to more losses. If speed of motor is reduced corresponding too low load and is increased corresponding to high load, then substantial amount of power can be saved. And speed can be changed by changing the frequency of input supply.
Implementation scheme of the Direct Torque Control strategy to Four Switch T...IJMER
This paper proposes a novel direct torque control (DTC) strategy for induction motor (IM) drives
fed by a four switch three-phase inverter (FSTPI). The introduced strategy is based on the emulation of the
operation of the conventional six switch three-phase inverter (SSTPI). This has been achieved thanks to a
suitable combination of the four unbalanced voltage vectors intrinsically generated by the FSTPI, leading to
the synthesis of the six balanced voltage vectors of the SSTPI.
This approach has been adopted in the design of the vector selection table of the proposed DTC
strategy which considers a subdivision of the Clarke plane into six sectors. Simulation results have revealed
that, thanks to the proposed DTC strategy, FSTPI-fed IM drives exhibit interesting performance. These have
been experimentally validated and compared to the ones yielded by the Takahashi and the basic DTC
strategies dedicated to the SSTPI and to the FSTPI, respectively.
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
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Embedded based sensorless control of pmbldc motor with voltage controlled pfc...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Review of the DTC Controller and Estimation of Stator Resistance in IM DrivesIAES-IJPEDS
In recent years an advanced control method called direct torque control
(DTC) has gained importance due to its capability to produce fast torque
control of induction motor. Although in these systems such variables as
torque, flux modulus and flux sector are required, resulting DTC structure is
particularly simplistic. Conventional DTC does not require any mechanical
sensor or current regulator and coordinate transformation is not present, thus
reducing the complexity. Fast and good dynamic performances and
robustness has made DTC popular and is now used widely in all industrial
applications. Despite these advantages it has some disadvantages such as
high torque ripple and slow transient response to step changes during start
up. Torque ripple in DTC is because of hysteresis controller for stator flux
linkage and torque. The ripples can be reduced if the errors of the torque and
the flux linkage and the angular region of the flux linkage are subdivided into
several smaller subsections. Since the errors are divided into smaller sections
different voltage vector is selected for small difference in error, thus a more
accurate voltage vector is selected and hence the torque and flux linkage
errors are reduced. The stator resistance changes due to change in
temperature during the operation of machine. At high speeds, the stator
resistance drop is small and can be neglected. At low speeds, this drop
becomes dominant. Any change in stator resistance gives wrong estimation
of stator flux and consequently of the torque and flux. Therefore, it is
necessary to estimate the stator resistance correctly. This paper aims to
review some of the control techniques of DTC drives and stator resistance
estimation methods.
Neural network based vector control of induction motorcsandit
Stator current drift compensation of induction motor based on RBF neural network is proposed
here. In vector control of induction motor decoupling of speed and rotor flux equations and
their simultaneous control are used to achieve the highest efficiency and fast dynamic
performance. The highest efficiency is reached when the proper flux is selected and as a result
of dynamic decoupling of speed and rotor flux equations, the rotor flux can be modified to
achieve the highest efficiency and make the speed be at its desired value. The precise control of
these changes can also be done using radial basis function neural network (RBFNN). Once
neural network gets trained then it is able to differentiate between normal and fault conditions
and therefore acts in accordance to the change that could bring back the system to normal
condition. Here, neural network is used to compute the appropriate set of voltage and frequency
to achieve the maximum efficiency for any value of operating torque and motor speed.
NEURAL NETWORK BASED VECTOR CONTROL OF INDUCTION MOTORcscpconf
Stator current drift compensation of induction motor based on RBF neural network is proposed here. In vector control of induction motor decoupling of speed and rotor flux equations and their simultaneous control are used to achieve the highest efficiency and fast dynamic performance. The highest efficiency is reached when the proper flux is selected and as a result
of dynamic decoupling of speed and rotor flux equations, the rotor flux can be modified to achieve the highest efficiency and make the speed be at its desired value. The precise control of
these changes can also be done using radial basis function neural network (RBFNN). Once neural network gets trained then it is able to differentiate between normal and fault conditions
and therefore acts in accordance to the change that could bring back the system to normal condition. Here, neural network is used to compute the appropriate set of voltage and frequency
to achieve the maximum efficiency for any value of operating torque and motor speed.
NEURAL NETWORK BASED VECTOR CONTROL OF INDUCTION MOTORcsandit
Stator current drift compensation of induction motor based on RBF neural network is proposed here. In vector control of induction motor decoupling of speed and rotor flux equations and their simultaneous control are used to achieve the highest efficiency and fast dynamic
performance. The highest efficiency is reached when the proper flux is selected and as a result of dynamic decoupling of speed and rotor flux equations, the rotor flux can be modified to achieve the highest efficiency and make the speed be at its desired value. The precise control of these changes can also be done using radial basis function neural network (RBFNN). Once
neural network gets trained then it is able to differentiate between normal and fault conditions and therefore acts in accordance to the change that could bring back the system to normal condition. Here, neural network is used to compute the appropriate set of voltage and frequency
to achieve the maximum efficiency for any value of operating torque and motor speed.
Fuzzy-Logic-Controller-Based Fault Isolation in PWM VSI for Vector Controlled...iosrjce
IOSR Journal of Electrical and Electronics Engineering(IOSR-JEEE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of electrical and electronics engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electrical and electronics engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Comparison of different controllers for the improvement of Dynamic response o...IJERA Editor
As the technology is fast changing, there is more and more use of machine intelligence in modern motor controllers. These controllers are employed in advanced electric motor drives in particular, the present day Induction motor drives. These systems emulate the human logic. This is particularly useful when the application has poorly defined mathematical model. In this present paper the analysis of fuzzy logic as the artificial intelligence is used. The comparative study of Fuzzy PI, Fuzzy MRAC is made. There is always a compromise of the cost and complexity. So this paper presents a new approach and its dynamic response in comparison to the Fuzzy PI and Fuzzy MRAC. The proposed controller is Fuzzy PI with scaling factors. This approach is validated with the Speed, torque responses of Indirect vector controlled Induction motor (IVCIM) drive.
Brushless DC Motor Drive during Speed Regulation with Artificial Neural Netwo...IJERA Editor
Brushless DC motor, at this moment is extensively used being many industrial functions due to the different
features like high efficiency and dynamic response and high speed range. This paper is proposing a technology
named as Artificial Neural Network controller to control the speed of the brushless DC motor. Here the paper
contributes an analysis of performance Artificial Neural Network controller. Because it is difficult to handle by
the use of conventional PID controller as BLDC drive is a nonlinear. Through PID controller, the speed
regulation of BLDC is not efficient and reliable as PID controller cannot operate the large data, results it gives
different variation in BLDC motor control. The ANN easily trains the data of large amount by NN toolbox. As
ANN controller has the strength to indulge characteristics of control and it is accessible to operate the huge
amount of data as like human can store in a mind. The empirical results prove that an ANN controller can better
control the act than the PID controller. The modelling, control and the simulation of the BLDCM get done by
applying MATLAB/SIMULINK software kit.
OPTIMAL TORQUE RIPPLE CONTROL OF ASYNCHRONOUS DRIVE USING INTELLIGENT CONTROL...elelijjournal
The dynamic performance of an asynchronous machine when operated with cascaded Voltage Source Inverter using Space Vector Modulation (SVM) technique is presented in this paper. A classical model of Induction Motor Drive based on Direct Torque Control (DTC) method is considered which displays
appreciable run-time operation with very simple hysteresis control scheme. Direct control of the torque and flux variables is achieved by choosing suitable inverter voltage space vector from a lookup table. Under varying torque conditions the performance of the drive system is verified using MATLAB/Simulink software tool. The ripple content in the torque parameter is significant when traditional PI controller and Fuzzy approach are configured in the proposed system. Finally, by replacing the PI-Fuzzy controller with Hybrid Controller the torque ripple minimization can be achieved during no-load and loaded conditions.
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.
QUICK DYNAMIC TORQUE CONTROL IN DTC-HYSTERESIS-BASED INDUCTION MOTOR BY USING...ijiert bestjournal
Induction machines are widely employed in industries due to their r ugged structure,high maintainability and economy than DC motors. There has been constant development in the i nduction motor drive system and their implementation in industrial applications. The improvement of switching speed of power electronic devices has enabled control techniques which possess high switching f requency and feasibility of high efficiency drive systems. In this pretext,Direct Torque Contr ol (DTC) was introduced to obtain quick and better dynamic torque response. The DTC scheme in its basic c onfiguration comprises torque and flux estimator DTC controller,stator voltage vector selector and voltage source inverter. Direct Torque Control of induction motor has increasingly become the best alternative to Field- Oriented Control methods. The performance of an induction motor under the classical Direct Torque Control method and improved scheme have been studied and confirmed by simulation using MATLAB.
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Induction motors are most commonly used motor type in industrial applications because of its well-known advantages like robust structure, cheaper prices etc. Today, field oriented control (FOC) and direct torque control (DTC) methods, also called vector control, are most famous control methods in high-performance applications. The main structural and behavioural differences between the both methods can be summarized as: the FOC has parameter dependence while the DTC has high torque ripples. In this study, a new adaptive bandwidth approach was presented to reduce torque ripples in DTC controlled induction motor drives. With the proposed method, instead of fixed bandwidth, adaptive bandwidth approach was investigated in hysteresis controllers on the DTC method. Both the conventional DTC(C-DTC) method and adaptive bandwidth DTC (AB-DTC) for induction motor were simulated in MATLAB/SIMULINK and the results were presented and discussed to verify the proposed control. The comparisons shown that, torque ripples were reduced remarkably with the proposed AB-DTC method.
Similar to 14. a variable speed, sensorless, induction motor drive (20)
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2. reconstructed from dc link quantities and the inverter recovery effect of diode, this leg is in fact shorted through at
switching signals. For faithful reconstruction of currents, use this moment such that a positive current spike will appear at
of adaptable gain band-pass filter is proposed in the scheme. the dc link side. To establish the basic relationship between dc
The simulation results of proposed scheme shows fast link current, winding currents and inverter switching pattern,
performance as compared to v/f control and therefore can be the switches shown in Fig. 2 are considered as ideal; the diode
regarded as an improvement. For the close loop speed control, recovery effect and the snubber action are not considered.
a single current sensor in the dc link is sufficient. Thus it is
suitable for low-cost, moderate performance, sensorless IM
drive applications. The proposed drive is modeled in
Matlab/Simulink software for a 2.2 kW IM. The simulation
results are presented to verify the workability of proposed
strategy.
II. PROPOSED SCHEME
Fig. 1 shows the block diagram of the proposed scheme. It
consists of a speed (frequency loop), a torque loop, and a Figure 2. Voltage source inverter fed induction motor drive
current regulator. The output of speed/frequency regulator
represents the torque reference for the torque loop. The torque A. Space-Vectors
regulator generates the q-axis current command iqe∗ . The d- During normal state, there are eight switching states of inverter
which can be expressed as space voltage vector (SA,SB,SC) such
axis current command i ∗ is directly generated from the as (0,0,0), (0,0,1), (0,1,0), (0,1,1), (1,0,0), (1,0,1), (1,1,0) and
de
reference rotor flux ψ r * as given by (1) [1]. This eliminates (1,1,1). SA =1 means upper switch of leg A is on while the
lower one is off, and vice versa. The same logic is applicable to
an additional PI controller and reduces the computational
SB and SC also. Amongst above eight voltage vectors, (0,0,0)
burden. These dc commands expressed in synchronously and (1,1,1) are termed as zero vectors while the other six as
rotating reference after transformation to the three phase active vectors. The switching vectors describe the inverter
current commands are than compared with the actual three- output voltages.
phase currents (reconstructed waveforms) to generate the
switching signals for the inverter. In the proposed scheme, all B. Basic Principle of Phase Voltage & Line Current
the feedback signals including the stator currents and stator Reconstruction
voltages are estimated/reconstructed from the dc link For different voltage vectors, the phase voltage that will
quantities. appear across stator winding can be determined by circuit
* ψ * (1) observation. This is summarized in Table 1. It is assumed that
i = r
de Lm the stator winding is star connected. From this table, the
expressions for the reconstruction of three phase voltages are
III. RECONSTRUCTION OF STATOR VOLTAGES & CURRENTS as follows (assuming no dwelling time):
FROM DC LINK
~ V
v = dc (2S − S − S ) (2)
a A B C
As indicated in [1], [6], the stator flux, torque and speed can 3
be derived from the stator voltages and currents expressed in ~ Vdc (3)
vb = (−S A + 2SB − SC )
d-q reference frame. The phase currents and voltages are 3
Vdc (4)
related to the dc link current and voltage by inverter switching ~
vc = (−S A − SB + 2SC )
states. A voltage source inverter-IM drive is shown in Fig. 2 3
where Vdc is the dc link voltage, Idc is the instantaneous dc link The stator voltages as expressed in stationary d-q frame are:
~ s ~ V (5)
current and ia, ib, ic are the instantaneous three-phase winding vqs = va = dc ( 2 S A − S B − SC )
currents. Generally, IGBTs associated with snubber protection 3
and feedback diode are used as switch in inverters. When a ~ s 1 ~ ~ V
vds = (vb − vc ) = dc (SB − SC ) (6)
switch is being turned-on and the conducting diode at the same 3 3
leg is being blocked off by this turn-on, because of the reverse
TABLE I. DC LINK CURRENT & PHASE VOLTAGES
Voltage Vector va (V) vb (V) vc (V) Idc (A)
(SA,SB,SC)
(0,0,0) 0 0 0 0
(0,0,1) -Vdc/3 -Vdc/3 2Vdc/3 + ic
(0,1,0) -Vdc/3 2Vdc/3 -Vdc/3 + ib
(0,1,1) -2Vdc/3 Vdc/3 Vdc/3 - ia
(1,0,0) 2Vdc/3 -Vdc/3 -Vdc/3 + ia
(1,0,1) Vdc/3 -2Vdc/3 Vdc/3 - ib
(1,1,0) Vdc/3 Vdc/3 -2Vdc/3 - ic
Figure 1. Block diagram of the proposed scheme. (1,1,1) 0 0 0 0
3592
3. The relationship between the applied active vectors and the can be obtained on integration of the phase voltage minus
phase currents measured from the dc link is also shown in voltage drop in the stator resistance Rs [1]:
Table 1. It is clear that at-most, one phase current can be ψ = (v
~
ds
~ s − R ~ s ) dt
∫ ds si ds
(15)
related to the dc.-link current at every instant. The
qs = ∫ (v qs
~
ψ ~ s − R ~ s ) dt (16)
reconstruction of phase currents from the dc-link current can s iqs
be achieved easily only if two active vectors are present for at ~ ~ ~
ψ s = ψ ds 2 + ψ qs 2 (17)
least enough time to be sampled. Fortunately, as indicated in ~ ~
~ ψ ~ ψ
cos θ e = ~ ; sin θ e = ~ (18)
[10], for most PWM strategies, two phase currents can be ds qs
sampled by looking at the dc link current over every PWM ψ s ψ s
period. If the PWM frequency is high enough, the phase ~
where θ e is the stator flux angle with respect to the q-axis of
current does not change much over one PWM period. Hence, a the stationary d-q frame.
reconstructed current derived from the dc link current gives a
reasonable approximation of the actual current. In terms of B. Estimation of Torque
switching states and Idc, the three ac line currents can be The electromagnetic torque can be expressed in terms of stator
derived as follows: currents and stator flux as follows [1]:
S
~
a
S
i = I (S − B − C )
dc A 2 2
(7) T =
e (ψ i −ψ i )
~ 3P ~ ~ s ~ ~ s
4 ds qs qs ds
(19)
~ S SC (8)
ib = I dc (− A + SB − ) C. Estimation of Synchronous Speed &Rotor Speed
2 2
S A SB ~
The synchronous speed ωe can be calculated from the
~
ic = Idc (− − + SC ) (9)
2 2 expression of the angle of stator flux as:
The stator currents as expressed in stationary d-q frame are: ~
~
ψ
θe = tan−1 ~ds (20)
~ s ~ ~ s 1 ~ ~ (10)
i =i ;
qs i =
a (2 i + i )
ds b a ψ qs
3
~
~ s ~ ~ s −1 ~ ~ (11) ~ dθ e (21)
or iqs = ia ; ids = ( 2 ic + ia ) ωe =
3 dt
~
To obtain the rotor speed ωr , simple slip compensation can be
~ s ~ ~
or iqs = −( ib − ic );
~ s
ids =
1 ~ ~
( i + ic )
(12)
3 b derived using the steady-state torque speed curve for the
machine being used:
C. Filter Stage ~
~
ω = KsTe (22)
The dc link current Idc consists of a train of short duration sl
pulses and has information about the stator currents of all the where Ks is the rated slip frequency/rated torque and it can be
three phases. By using (7)-(9), these pulses can be segregated derived from the name plate of the machine. Alternately, if the
into three ac line currents. Generally, an active or passive-type rotor flux ψ r is assumed as constant, the slip speed can also
low-pass filter (LPF) with narrow bandwidth is used to filter be calculated as:
out the high frequency components in the ac current waveform ~ s
~ R ' iqs (23)
thus obtained from Idc. This filter actually works as an ω = r ~
sl Lr ' ids s
integrator. However, a LPF causes phase lag and amplitude
attenuation that vary with fundamental frequency [11]. In this The rotor speed is than given by,
~ ~ ~
ωr = ωe − ωsl (24)
paper, we propose the use of band-pass filter with adaptable
gain to overcome this problem. The transfer function of the
filter is given below: V. PROPOSED CONTROL STRATEGY
⎡⎛ sT ⎞⎛ T ⎞⎤ (13) Majority of IM drives are of open-loop, constant-v/f, voltage-
y= ⎢⎜ 1 + sT ⎟⎜ 1 + sT ⎟⎥
x
⎣⎝ ⎠⎝ ⎠⎦ source-inverter type. These drives are cost effective but they
offer sluggish response. Due to high current transients during
where x, y and T are input, output and time constant of the the torque changes, they are subject to undesirable trips. To
band-pass filter. For sT >>1; (1+sT) ≅ 1. Therefore, avoid the un-necessary trips, the control parameters like
1 (14) acceleration/deceleration rate has to be adjusted (reduced)
y= x
s according to the load. This results in underutilization of torque
capability of the motor. Thus the drawback of v/f drive can be
IV. ESTIMATION OF FEEDBACK SIGNALS FROM attributed to lack of torque control. This is the reason why
RECONSTRUCTED QUANTITIES open-loop, constant-v/f drives are mostly used in low
The feedback signals required to simulate the proposed performance fan and pump type loads. In this paper, we
scheme i.e., flux, torque and rotor speed are estimated as: propose a modified control scheme that includes the torque
control and a current regulated PWM inverter to avoid the
A. Estimation of Flux undesirable trips due to transient currents.
The stator flux in stationary d-q frame ψ s ,ψ qs s and thus ψ s As shown in Fig.1, the feedback signals i.e. torque and rotor
ds
speed are obtained from the dc link quantities and hence from
3593
4. the reconstructed line currents and phase voltages. The 500
accuracy of reconstructed waveforms depends upon the
a )
v (V
0
sampling rate [8], [9]. Higher the sampling rate less is the error
-500
between the actual and reconstructed waveforms. In a hard- 0.05 0.06 0.07 0.08 0.09 0.1
switching inverter, the switching frequency is limited to a 500
typical value of a few kHz. This limits the sampling rate of dc
b )
v (V
0
current and hence the update rate of torque and rotor speed.
Consequently, closing the loop directly on the instantaneous -500
0.05 0.06 0.07 0.08 0.09 0.1
value of the estimated torque now becomes difficult because 500
estimation error during a PWM cycle could become
c )
v (V
significantly high. In order to use the estimated torque in a 0
more robust manner, a control strategy should use the -500
averaged torque instead of the instantaneous value. This leads 0.05 0.06 0.07 0.08
Tim e (s )
0.09 0.1
to the control strategy depicted in Fig.1. In this system, two P- (a)
I controllers are used to regulate the average value of torque
iAind lin ( )
c kA
5
and speed. The output of the P-I regulators forms the q-axis 0
reference in a synchronously rotating reference frame. -5
1.78 1.8 1.82 1.84
VI. SIMULATION STUDIES
iBind lin ( )
c kA
5
In order to predict the behavior of the drive during steady-state 0
and transient conditions, detailed simulation studies of the -5
scheme shown in Fig.1 are carried out on a 2.2kW IM by
1.78 1.8 1.82 1.84
iC d lin ( )
in c k A
5
using Simulink software. Fig. 3. shows the internal structure of
the controller that consists of the speed loop, torque loop and
0
the current regulation loop in synchronously rotating frame of -5
1.78 1.8 1.82 1.84
reference. The switching signals for inverter are generated by Time (A)
(b)
comparing the command ac currents with reconstructed ac
Figure 4. Reconstructed waveforms of (a) three phase voltages and (b) three
currents. For the reconstruction of stator voltages and ac line
line currents separated from the dc link current.
currents, the dc link quantities with Vdc = 600V are sampled
with a sampling time of 2e-6 seconds and than segregated into values of time constants T for the band-pass filter are selected
the three-phase voltages and three ac currents as per (2)-(4) by trial and error. The simulation output of band-pass filter
and (7)-(9) respectively. The simulation was carried out for which represents the reconstructed ac line currents is shown in
five different operating conditions as is presented ahead. A Fig.5(a). For the sake of comparison, the actual ac line
variable- step ode23tb(stiff/TR-BDF2) solver was used. The currents are illustrated in Fig.5(b). The reconstructed and
waveforms of reconstructed phase voltages and the three ac actual waveforms of ac line currents during 100% speed
line currents as reflected in the dc current, are presented in reversal at no-load are presented in Fig.6(a) & (b). The
Fig.4. From these waveforms, it is clear that the samples of response of speed sensorless drive during different
phase currents available in the dc link current are not evenly
)
econstructed line
currents 'a,b,c',(A
5
spread and being discontinuous, the set of resulting points do
0
not constitute an acceptable reconstruction. Therefore a zero-
order hold is employed followed by a band-pass filter. The -5
R
1.78 1.8 1.82 1.84
Tim e (s )
(a)
c re ts'ab ' ( )
ur n , ,c A
5
c a e
Atu l lin
0
-5
1.78 1.8 1.82 1.84
Time (s)
(b)
Figure 5. Stator currents at rated load (a) reconstructed (b) actual waveforms
R c n tr c d
10
e o s u te
c r e ts ( )
ur n A
0
-10
1.1 1.2 1.3
Time (s)
Figure 3. Simulink model of control strategy (a)
3594
5. outer speed loop and is very similar to open-loop v/f drive in
A tu l c r e ts( )
c a ur n A
10
0
terms of power components and sensors required. Due to the
-10
inclusion of torque control loop, the drive response is fast and
1.1 1.2 1.3 stable. Simulation results confirm the effectiveness of the
Time (A)
proposed scheme. The technique uses only dc link voltage and
(b) dc link current measurements to generate the estimates of
Figure 6. Stator currents during reversal at no-load (a) reconstructed
E tim te toq e( .u E t a ds e d( .u)
s a d r u p ) sim te p e p .
waveform (b) actual waveform 1
0.5
dynamic conditions was studied in detail. To check the
accuracy of estimated variables, these variables were obtained 0
0 0.1 0.2 0.3 0.4 0.5
by two different methods. In the first one, the machine 15
10
variables which include the flux, torque, synchronous-speed, 5
slip-speed and rotor-speed are estimated by using (15)-(24) 0
and in the second method, these variables are calculated with -5
0 0.1 0.2 0.3 0.4 0.5
the help of dynamic model of IM [1] by using the stator Tim e (s )
(a)
currents and voltages measured directly. The simulation
cu l p e pu)
At a s e d( . .
results of the first method were treated as estimated values 1
while those of the latter method as actual values. 0.5
Case 1: Free acceleration characteristics: 0
The machine was allowed to accelerate from zero speed to
0 0.1 0.2 0.3 0.4 0.5
cu l oq e pu)
15
At a t r u ( . .
rated speed at no-load. The steady-state was reached at 0.3 10
seconds. The waveform of estimated speed show faster 5
0
response (less damped) as compared to its actual counterpart. -5
This is shown in Fig. 7(a) & (b). 0 0.1 0.2 0.3
Tim e (s )
0.4 0.5
Case 2: Step change in speed reference: (b)
Step change in speed reference was applied two times. At 0.5 Figure 7. Free-acceleration characteristics (a) estimated & (b) actual values
sec., from +100% to +60% and vice-versa at 1 sec. was
Et a dt r u ( .u Et ae s e d p .)
simt oq e p .) simt d pe ( .u
applied. The response is shown in Fig.8. The torque becomes 1
negative during the first change to decelerate the motor. Upon 0.5
reaching steady state, the torque becomes equal to the load 0
torque. The response time of the drive for this step change is 10
0.4 0.6 0.8 1 1.2
100ms. The estimated values of torque and speed vary in 0
accordance with their corresponding actual values.
e
-10
Case 3: Speed reversal: 0.4 0.6 0.8 1 1.2
A step change in speed reference from +100% to -100% is Time (s)
(a)
applied at 1.5 seconds. This step change is equivalent to 100%
A tu l s e d(p .)
c a p e .u
1
speed change. The response is shown in Fig. 9. The phase
sequence reverses to rotate the motor in reverse direction. The 0.5
drive reaches steady state after the change in reference speed 0
0.4 0.6 0.8 1 1.2
in 700 ms. this proves that the speed estimation is stable even
A tu l to u (p .)
10
c a rq e .u
at very low speeds.
Case 4: Step change in load:
0
A step change in load is applied at 0.5 seconds. The response -10
of the drive is shown in Fig.10. The electromagnetic torque 0.4 0.6 0.8
Tim e (s )
1 1.2
increases to correct the speed error. Upon reaching the steady (b)
state, the torque becomes equal to the load torque. The rotor Figure 8. Variation in rotor speed and electromagnetic torque for step
speed, after an initial droop attains back its earlier speed . The changes in reference speed (a) estimated values, (b) actual values
motor reaches the steady state in 300ms.
s a d oq e p . s a d p e p .)
E timte t r u ( .u)E timte s e d( .u
Case 5: Low speed operation: 1
The response of the drive at 40% and 20% of rated speed is 0
shown in Fig.11. For the machine under consideration, 20% -1
corresponds to 3.14 rad/sec angular mechanical speed. The 1.4 1.6 1.8 2 2.2
speed estimation is very stable even at this low speed range. 5
0
VII. CONCLUSION -5
-10
In this paper, a new control strategy for induction motor drive 1.4 1.6 1.8
Time (s)
2 2.2
is proposed. The drive is operated under torque control with an (a)
3595
6. A tu l s e d(p .)
phase voltages, line currents, flux, torque and rotor speed. If
c a p e .u
1
0 the dc link voltage is assumed as constant, only one current
-1
sensor in the dc link is sufficient to give the estimates of all
1.4 1.6 1.8 2 2.2
required feedback variables. Moreover, the same current
sensor that is already available in the dc link of an open-loop
A a to u (p .)
5
ctu l rq e .u
0 v/f drive for protection purpose can be used. Thus the open-
-5 loop control strategy in an existing v/f drive can be replaced
-10 by the proposed close-loop control strategy without requiring
1.4 1.6 1.8
Time (s)
2 2.2
any additional power components or the physical sensors. The
(b) proposed strategy appears to be a good compromise between
Figure 9. Variation in rotor speed and electromagnetic torque during reversal the high-cost, high-performance field-oriented drives and the
(a) estimated values, (b) actual values low-cost, low-performance v/f drives.
Practical implementation of the proposed scheme on a 16
E tim te toq e( .u E tim te s e d(p .)
s a d r u p .) s a d p e .u
1 bits floating point arithmetic Texas Instrument TMS320C31
processor are the subject of future follow-up research work.
0.5
APPENDIX
0
0 0.2 0.4 0.6 0.8 1
MACHINE PARAMETERS
15
10 Rs = 11.1Ω; R’r = 2.2605Ω
5 Ls = 0.7329H; L’r = 0.7329H
0
Lm = 0.71469H; P = 4
-5
0 0.2 0.4 0.6 0.8 1
Time (s)
(a) REFERENCES
[1] B. K. Bose, Power Electronics and Motor Drives, Delhi,
c a p e p .)
A tu l s e d( .u
1
India, Pearson Education, Inc., 2003.
0.5 [2] M. Rodic and K. Jezernik, “Speed-sensorless sliding-mode
torque control of induction motor,” IEEE Trans. Ind.
0
0 0.2 0.4 0.6 0.8 1 Electron., vol. 49, no. 1, pp. 87-95, Feb. 2002.
c a r u p .)
15
[3] L. Harnefors, M. Jansson, R. Ottersten, and K. Pietilainen,
A tu l toq e( .u
10
5
“Unified sensorless vector control of synchronous and
0
induction motors,” IEEE Trans. Ind. Electron., vol. 50, no. 1,
-5 pp. 153-160, Feb. 2003.
0 0.2 0.4 0.6 0.8 1
Time (sec) [4] M. Comanescu and L. Xu, “An improved flux observer based
(b) on PLL frequency estimator for sensorless vector control of
Figure 10. Variation in rotor speed and electromagnetic torque with step rise induction motors,” IEEE Trans. Ind. Electron., vol. 53, no. 1,
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