Nowadays, asynchronous motors have wide range use in many industrial applications. Field oriented
control (FOC) and direct torque control (DTC) are commonly used methods in high performance vector
control for asynchronous motors. Therefore, it is very important to identify clearly advantages and
disadvantages of both systems in the selection of appropriate control methods for many industrial
applications. This paper aims to present a new and different perspective regarding the comparison of the
switching behaviours on the FOC and the DTC drivers. For this purpose, the experimental studies have
been carried out to compare the inverter switching frequencies and torque responses of the asynchronous
motor in the FOC and the DTC systems under different working conditions. The dSPACE 1103 controller
board was programmed with Matlab/Simulink software. As expected, the experimental studies showed that
the FOC controlled motors has a lessened torque ripple. On the other hand, the FOC controlled motor
switching frequency has about 65-75% more than the DTC controlled under both loaded and unloaded
working conditions
Field oriented control and direct torque control are the most popular methods in high
performance industrial control applications for induction motors. Naturally, the strengths and
weaknesses of each control method are available. Therefore, the selection of optimum control
method is vitally important for many industrial applications. So, the advantages and the
disadvantages of both control methods have to be well defined. In this paper, a new and
different perspective has been presented regarding the comparison of the inverter switching
behaviours on the FOC and the DTC drivers. For this purpose, the experimental studies have
been carried out to compare the inverter switching frequencies and torque responses of
induction motors in the FOC and the DTC systems. The dSPACE 1103 controller board has
been programmed with Matlab/Simulink software. As expected, the experimental studies have
showed that the FOC controlled motors have had a lessened torque ripple. On the other hand,
the FOC controlled motor switching frequency has about 75% more than the DTC controlled.
Experiment based comparative analysis of stator current controllers using pre...journalBEEI
The stator current control loop plays an important role in ensuring the quality of electric drives interm of producing fast and adequate required torque. When the current controller provides ideal responses, speed control design subsequently is in charge of improving the system performances. Classical PID control is commonly used in current loop design, this paper presents the comparative analysis of current stator controller using proportional integral control and predictive current control (PCC) in field-oriented control-based induction motor drives, with rigidly coupled loads. The experimental results show system responses with PID and PCC. Informative experiment-based analysis provides primary guidance in selection between the two controls.
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.
MODIFIED DIRECT TORQUE CONTROL FOR BLDC MOTOR DRIVESijctcm
In this paper, a new adaptive reference based approach to direct torque control (DTC) method has been
proposed for brushless direct current (BLDC) motor drives. Conventional DTC method uses two main
reference parameters as: flux and torque. A main difference from the conventional method of it was that
only one reference parameter (speed) was used to control the BLDC motor and the second control
parameter (flux) was obtained from speed error through the proposed control algorithm. Thus, the DTC
performance has been especially improved on systems which need variable speed and torque during
operation, like electric vehicles. The dynamic models of the BLDC and the DTC method have been created
on Matlab/Simulink. The proposed method has been confirmed and verified by the dynamic simulations on
different working conditions. The simulation studies showed that the proposed method reduced remarkably
the speed and the torque ripples when compared the conventional DTC method. Moreover, the proposed
method has also very simple structure to apply the conventional DTC and its extra computational load to
the controller is almost zero.
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.
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.
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.
Field oriented control and direct torque control are the most popular methods in high
performance industrial control applications for induction motors. Naturally, the strengths and
weaknesses of each control method are available. Therefore, the selection of optimum control
method is vitally important for many industrial applications. So, the advantages and the
disadvantages of both control methods have to be well defined. In this paper, a new and
different perspective has been presented regarding the comparison of the inverter switching
behaviours on the FOC and the DTC drivers. For this purpose, the experimental studies have
been carried out to compare the inverter switching frequencies and torque responses of
induction motors in the FOC and the DTC systems. The dSPACE 1103 controller board has
been programmed with Matlab/Simulink software. As expected, the experimental studies have
showed that the FOC controlled motors have had a lessened torque ripple. On the other hand,
the FOC controlled motor switching frequency has about 75% more than the DTC controlled.
Experiment based comparative analysis of stator current controllers using pre...journalBEEI
The stator current control loop plays an important role in ensuring the quality of electric drives interm of producing fast and adequate required torque. When the current controller provides ideal responses, speed control design subsequently is in charge of improving the system performances. Classical PID control is commonly used in current loop design, this paper presents the comparative analysis of current stator controller using proportional integral control and predictive current control (PCC) in field-oriented control-based induction motor drives, with rigidly coupled loads. The experimental results show system responses with PID and PCC. Informative experiment-based analysis provides primary guidance in selection between the two controls.
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.
MODIFIED DIRECT TORQUE CONTROL FOR BLDC MOTOR DRIVESijctcm
In this paper, a new adaptive reference based approach to direct torque control (DTC) method has been
proposed for brushless direct current (BLDC) motor drives. Conventional DTC method uses two main
reference parameters as: flux and torque. A main difference from the conventional method of it was that
only one reference parameter (speed) was used to control the BLDC motor and the second control
parameter (flux) was obtained from speed error through the proposed control algorithm. Thus, the DTC
performance has been especially improved on systems which need variable speed and torque during
operation, like electric vehicles. The dynamic models of the BLDC and the DTC method have been created
on Matlab/Simulink. The proposed method has been confirmed and verified by the dynamic simulations on
different working conditions. The simulation studies showed that the proposed method reduced remarkably
the speed and the torque ripples when compared the conventional DTC method. Moreover, the proposed
method has also very simple structure to apply the conventional DTC and its extra computational load to
the controller is almost zero.
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.
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.
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.
Comparison of Estimated Torques Using Low Pass Filter and Extended Kalman Fil...IAES-IJPEDS
Torque calculation process is one of the major concerns for controlling induction motors in industry, which requires very accurate state estimation of unmeasurable variables of nonlinear models. This can be solved if the variables used for torque calculation is accurately estimated. This paper presents a torque calculation based on a voltage model represented with a low-pass filter (LPF), and an extended Kalman filter (EKF). The experimental results showed that the estimated torque at low speed based on EKF is more accurate in the expense of more complicated and larger computational time.
Comparative Study of the Success of PI and PI-Fuzzy Controller for Induction ...inventionjournals
Asynchronous motors have a wide range of applications in the industry.Therefore, speed control of asynchronous motors is of great importance.Speed control of asynchronous motors based on vector control techniques to achieve high performance.The vector control technique, motor flux and moment variables can be controlled independently of each other.Because of the nonlinear and complex model of asynchronous motors, the speed control applications of these motors are not provided with great efficiency by classical control methods.Fuzzy logic controllers (FLC), which were successful in many areas, present great performance in speed control of an asynchronous motor.In this study, a simulation study regarding speed control of a threephase squirrel cage asynchronous motor was carried out with a PI-Fuzzy type FLC and a conventional PI type controller.The data obtained by simulation are evaluated and the performances of the control methods are compared.
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.
STATOR FLUX OPTIMIZATION ON DIRECT TORQUE CONTROL WITH FUZZY LOGIC cscpconf
The Direct Torque Control (DTC) is well known as an effective control technique for high
performance drives in a wide variety of industrial applications and conventional DTC technique
uses two constant reference value: torque and stator flux. In this paper, fuzzy logic based stator
flux optimization technique for DTC drives that has been proposed. The proposed fuzzy logic
based stator flux optimizer self-regulates the stator flux reference using induction motor load situation without need of any motor parameters. Simulation studies have been carried out with Matlab/Simulink to compare the proposed system behaviors at vary load conditions. Simulation results show that the performance of the proposed DTC technique has been improved and especially at low-load conditions torque ripple are greatly reduced with respect to the conventional DTC
A New Induction Motor Adaptive Robust Vector Control based on Backstepping IJECEIAES
In this paper, a novel approach to nonlinear control of induction machine, recursive on-line estimation of rotor time constant and load torque are developed. The proposed strategy combines Integrated Backstepping and Indirect Field Oriented Controls. The proposed approach is used to design controllers for the rotor flux and speed, estimate the values of rotor time constant and load torque and track their changes on-line. An open loop estimator is used to estimate the rotor flux. Simulation results are presented which demonstrate the effectiveness of the control technique and on-line estimation.
Investigation of Artificial Neural Network Based Direct Torque Control for PM...cscpconf
This paper investigates solution for the chronically and the biggest problem of direct torque control scheme: high torque ripple. Otherwise, another main problem faced in direct torque control method is difficulties due to complex algorithm to get high performance control for industrial motors. The purpose of this paper is to simplify the control structure by using artificial neural networks learning abilities and to investigate the affects of this structure on torque performance of motor. For this purpose, two different artificial neural networks have been suggested replacing the optimal switching vector selection and flux sector determination process of conventional direct torque control method. Matlab/Simulink based numerical simulations have been carried out to compare motor performances with conventional control structure and proposed artificial neural network based structure. It has been observed that the dynamic response of motor is faster and torque ripple and the controller complexity of the conventional control system has been reduced with the proposed technique.
SENSORLESS VECTOR CONTROL OF BLDC USING EXTENDED KALMAN FILTER sipij
This Paper mainly deals with the implementation of vector control technique using the brushless DC motor
(BLDC). Generally tachogenerators, resolvers or incremental encoders are used to detect the speed. These
sensors require careful mounting and alignment, and special attention is required with electrical noises. A
speed sensor need additional space for mounting and maintenance and hence increases the cost and size of
the drive system. These problems are eliminated by speed sensor less vector control by using Extended
Kalman Filter and Back EMF method for position sensing. By using the EKF method and Back EMFmethod, the sensor less vector control of BLDC is implemented and its simulation using MATLAB/SIMULINK and hardware kit is implemented.
Direct Torque Control of Four Switch Three Phase Inverter Fed Induction Motor...IAES-IJPEDS
This paper presents sensorless speed control of induction motor (IM) using four switch three phase inverter (FSTPI) with direct torque and flux control (DTFC). The proposed sensorless DTFC system consists of an adaptive observer of rotor flux to accurately estimate stator resistance and speed simultaneously, without affecting drive performances. The switching technique for DTFC of IM using FSTPI in low power application is based on the principle of similarity between FSTPI and SSTPI (six switch three phase inverter), where the αβ plan is divided into 6 sectors and the formation of the voltage space vector is done in the same way as for SSTPI by using effective (mean) vectors. This approach allows using the well-known established switching table of SSTPI for FSTPI. The simulation results indicates that the sensorless speed control of FSTPI fed IM with DTFC and adaptive observer provides accurate estimate, good trajectory tracking with different dynamics performance. The experimental results verify the effectiveness of the proposed method at different operating points.
FLC-Based DTC Scheme for a New Approach of Two-Leg VSI Fed Induction MotorIJERA Editor
A new Direct Torque Control (DTC) strategy for Induction Motor (IM) drive fed by a two leg three phase
inverter (i.e., Four switches are used in VSI) was proposed in this paper. The proposed methodology is based on
the emulation of operation of the conventional Six-switch three phase inverter. The combination of four
unbalanced voltage vectors is generated by the two-leg three phase inverter, approaching to the synthesis of the
six balanced voltage vectors of the conventional DTC. This approach has been implemented in the design of the
vector selection table of the proposed DTC strategy. Further, Fuzzy Logic Controller (FLC) is proposed in the
speed controller for the improvement of torque ripples. Convention DTC with Six Switch three phase VSI, twoleg
three phase VSI with PI and Fuzzy Controller are implemented using MATLAB/SIMULINK. Simulation
results have shown that the proposed DTC strategy, two-leg inverter fed IM drive revealed an improved
performance.
Fuzzy logic based direct torque control of induction motor with space vector ...ijscai
The induction motors have wide range of applications for due to its well-known advantages like brushless
structures, low costs and robust performances. Over the past years, many kind of control methods are
proposed for the induction motors and direct torque control has gained huge importance inside of them due
to fast dynamic torque responses and simple control structures. However, the direct torque control method
has still some handicaps against the other control methods and most of the important of these handicaps is
high torque ripple. This paper suggests a new approach, Fuzzy logic based space vector modulation, on
the direct torque controlled induction motors and aim of the approach is to overcome high torque ripple
disadvantages of conventional direct torque control. In order to test and compare the proposed direct
torque control method with conventional direct torque control method simulations, in Matlab/Simulink,
have been carried out in different working conditions. The simulation results showed that a significant
improvement in the dynamic torque and speed responses when compared to the conventional direct torque
control method.
This paper presents the comparative performances of Indirect Field Oriented Control (IFOC) for the three-phase induction motor. Recently, the interest of widely used the induction motor at industries because of reliability, ruggedness and almost free in maintenance. Thus, the IFOC scheme is employed to control the speed of induction motor. Therefore, P and PI controllers based on IFOC approach are analyzed at differences speed commands with no load condition. On the other hand, the PI controller is tuned based on Ziegler-Nichols method by using PSIM software which is user-friendly for simulations, design and analysis of motor drive, control loop and the power converter in power electronics studies. Subsequently, the simulated of P controller results are compared with the simulated of PI controller results at difference speed commands with no load condition. Finally, the simulated results of speed controllers are compared with the experimental results in order to explore the performances of speed responses by using IFOC scheme for three-phase induction motor drives.
This paper presents a study concerning a sensorless vector control of an induction machine fed by a voltage source inverter. The aim is to provide a scheme to control the speed and the rotor flux using a sensorless integral backstepping control approach. The rotor speed estimation is done by an observer using the model reference adaptive system (MRAS) technique whereas the nonlinear backstepping observer is used to get the rotor flux. The main objective is to achieve a robust control, adaptive and efficient, which will allow us to test and evaluate the performance of the proposed observer, combined with a sensorless control of the induction machine. Tests and validation are done using numerical simulations with MATLAB/SIMULINK-PSB (Power System Block set) toolbox. The results show good performance in terms of robustness regarding machine parameter variations and show the excellent quality of the control law associated with the observer, despite the observability problems when the machine operates at low speed.
Performance Analysis of a DTC and SVM Based Field- Orientation Control Induct...IJPEDS-IAES
This study presents a performance analysis of two most popular control strategies for Induction Motor (IM) drives: direct torque control (DTC) and space vector modulation (SVM) strategies. The performance analysis is done by applying field-orientation control (FOC) technique because of its good dynamic response. The theoretical principle, simulation results are discussed to study the dynamic performances of the drive system for individual control strategies using actual parameters of induction motor. A closed loop PI controller scheme has been used. The main purpose of this study is to minimize ripple in torque response curve and to achieve quick speed response as well as to investigate the condition for optimum performance of induction motor drive. Depending on the simulation results this study also presents a detailed comparison between direct torque control and space vector modulation based field-orientation control method for the induction motor drive.
A Novel Optimal PI Parameter Tuning Strategy to Improve Constant Switching Pe...IJPEDS-IAES
This paper presents a novel method of optimal Propotional-Intergral (PI)
controller’s parameter tuning strategy in-order to improve the constant
switching performance of 3-phase direct torque control (DTC) shceme. The
DTC sheme is acknowledged to provide fast decoupled control over the
torque output and stator flux via a simple control structure. However, DTC
sheme has two major downsides, which are the inconsistent inverter
switching frequency and high torque output ripple. The main reason that
contributes to these tribulations is the usage of hysteresis comparators in
order to control the output torque. The realization of PI based controller
method as replacement of hyterisis controller in DTC system able to provide
significant solutions to over come the fall back while retaining the simple
control structure of conventional DTC. The combination usage of higher
sampling controller DS1004 and also 3-level cascaded H-bridge multilevel
inverters (CHMI) in this system can further minimize the output torque ripple
by providing higher resolution with lower digital error and greater number of
vectors. This paper presents detail explanation and calculation of optimal PI
parameter tuning strategy consecutively to enhance the performance of 3-
level DTC system. In order to verify the feasibility of the proposed method
experimentation, the proposed method is compared with convention DTC
system via simulation and experiment results.
Experimental Evaluation of Torque Performance of Voltage and Current Models u...IJPEDS-IAES
In this paper, two kinds of observers are proposed to investigate torque estimation. The first one is based on a voltage model represented with a low- pass filter (LPF); which is normally used as a replacement for a pure integrator to avoid integration drift problem due to dc offset or measurement error. The second estimator used is an extended Kalman filter (EKF) as a current model, which puts into account all noise problems. Both estimation algorithms are investigated during the steady and transient states, tested under light load, and then compared with the measured mechanical torque. In all conditions, it will be shown that the torque estimation error for EKF has remained within narrower error band and yielded minimum torque ripples when compared to LPF estimation. This motivates the use of EKF observer in high performance control drives of induction machines for achieving improved torque response.
RANDOM PULSEWIDTH MODULATION TECHNIQUE FOR A 4-LEVEL INVERTERIAEME Publication
Random Pulse Width Modulation (RPWM) technique for a 4-level inverter in open-end winding induction motor configuration is proposed i n this paper. Reference voltage space vector is randomly sampled and it is realized in average sens e by switching its three nearest vectors. Switching frequency is randomly varied within the bounds to get randomly s paced samples. The method requires no sector identification. The refer encephasor is converted into a vector lying in the basic 2-level inverter to calculate switching time vectors. The proposed scheme is implemented and experimental results are presented for a dual inverter fed 4-level open-end winding induction motor drive using DSP platform, TMS 320LF2407A.
Control of Four Switch Three Phase Inverter Fed Induction Motor Drives Based ...IJPEDS-IAES
This paper presents sensorless position and speed control for a four-switch three-phase inverter (FSTPI) fed induction motor drive. Accurate knowledge of stator resistance is of utmost importance for correct operation of a number of speed sensorless induction motor control schemes in the low speed region. Since stator resistance inevitably varies with operating conditions, stable and accurate operation at near-zero speed requires an appropriate identification algorithm for the stator resistance. The paper proposes such an identification algorithm, which is developed for the rotor flux based model reference adaptive system (MRAS) type of the speed estimator in conjunction with a rotor flux oriented control scheme. In this speed estimation method only one (out of the two available) degree of freedom is utilized for speed estimation. It is utilize the second available degree of freedom as a mean for adapting the stator resistance. The parallel stator resistance and rotor speed identification algorithm is developed in a systematic manner, using Popov’s hyper stability theory. It increases the complexity of the overall control system insignificantly and enables correct speed estimation and stable drive operation at near-zero speeds. The proposed speed and position estimator with parallel stator resistance identification for FSTPI fed induction motor at very low speed under high load operation is verified by simulation and experimental results. The results show the robustness of the proposed method with FSTPI.
In a Power plant with a Distributed Control System ( DCS ), process parameters are continuously stored in
databases at discrete intervals. The data contained in these databases may not appear to contain valuable
relational information but practically such a relation exists. The large number of process parameter values
are changing with time in a Power Plant. These parameters are part of rules framed by domain experts for
the expert system. With the changes in parameters there is a quite high possibility to form new rules using
the dynamics of the process itself. We present an efficient algorithm that generates all significant rules
based on the real data. The association based algorithms were compared and the best suited algorithm for
this process application was selected. The application for the Learning system is studied in a Power Plant
domain. The SCADA interface was developed to acquire online plant data.
APPLYING AN ARABIC CONVERSATIONAL AGENT IN THE JORDANIAN E-GOVERNMENTijcsit
This paper discusses a prototype idea of applying a Conversational Agent (CA) to be embedded into the Jordanian E-government websites. The Conversational Agent is a smart system used to handle natural conversations between user and machine. A Jordanian citizen facing struggles when he/she want to apply for a service through the E-government portal.In addition the Jordanians struggling when searched for a
piece of information (for example the needed documents for a specific service) inside the E-government websites. This struggling comes from number of reasons such as the needed knowledge that the user could have to deal with such services and the big number of links that the user must visitto achieve his/her target.In addition, the Jordanian E-Government websites does not meet the users’ requirements in their design.
Instead, this paper proposes the idea of applying a prototype called CA into those websites as a general help desk automated service to save the Jordanians time and effort. Simply, the user will chat with the proposed CA with what he/she coming to do through the targeted website using a text based Arabic conversations. The CA’s responses might be the exact needed link or the targeted information. Such a proposed service will strength the Jordanian E-government platform especially for accessibility and usability factors and as to best of our knowledge, no country has been applied it before.
Comparison of Estimated Torques Using Low Pass Filter and Extended Kalman Fil...IAES-IJPEDS
Torque calculation process is one of the major concerns for controlling induction motors in industry, which requires very accurate state estimation of unmeasurable variables of nonlinear models. This can be solved if the variables used for torque calculation is accurately estimated. This paper presents a torque calculation based on a voltage model represented with a low-pass filter (LPF), and an extended Kalman filter (EKF). The experimental results showed that the estimated torque at low speed based on EKF is more accurate in the expense of more complicated and larger computational time.
Comparative Study of the Success of PI and PI-Fuzzy Controller for Induction ...inventionjournals
Asynchronous motors have a wide range of applications in the industry.Therefore, speed control of asynchronous motors is of great importance.Speed control of asynchronous motors based on vector control techniques to achieve high performance.The vector control technique, motor flux and moment variables can be controlled independently of each other.Because of the nonlinear and complex model of asynchronous motors, the speed control applications of these motors are not provided with great efficiency by classical control methods.Fuzzy logic controllers (FLC), which were successful in many areas, present great performance in speed control of an asynchronous motor.In this study, a simulation study regarding speed control of a threephase squirrel cage asynchronous motor was carried out with a PI-Fuzzy type FLC and a conventional PI type controller.The data obtained by simulation are evaluated and the performances of the control methods are compared.
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.
STATOR FLUX OPTIMIZATION ON DIRECT TORQUE CONTROL WITH FUZZY LOGIC cscpconf
The Direct Torque Control (DTC) is well known as an effective control technique for high
performance drives in a wide variety of industrial applications and conventional DTC technique
uses two constant reference value: torque and stator flux. In this paper, fuzzy logic based stator
flux optimization technique for DTC drives that has been proposed. The proposed fuzzy logic
based stator flux optimizer self-regulates the stator flux reference using induction motor load situation without need of any motor parameters. Simulation studies have been carried out with Matlab/Simulink to compare the proposed system behaviors at vary load conditions. Simulation results show that the performance of the proposed DTC technique has been improved and especially at low-load conditions torque ripple are greatly reduced with respect to the conventional DTC
A New Induction Motor Adaptive Robust Vector Control based on Backstepping IJECEIAES
In this paper, a novel approach to nonlinear control of induction machine, recursive on-line estimation of rotor time constant and load torque are developed. The proposed strategy combines Integrated Backstepping and Indirect Field Oriented Controls. The proposed approach is used to design controllers for the rotor flux and speed, estimate the values of rotor time constant and load torque and track their changes on-line. An open loop estimator is used to estimate the rotor flux. Simulation results are presented which demonstrate the effectiveness of the control technique and on-line estimation.
Investigation of Artificial Neural Network Based Direct Torque Control for PM...cscpconf
This paper investigates solution for the chronically and the biggest problem of direct torque control scheme: high torque ripple. Otherwise, another main problem faced in direct torque control method is difficulties due to complex algorithm to get high performance control for industrial motors. The purpose of this paper is to simplify the control structure by using artificial neural networks learning abilities and to investigate the affects of this structure on torque performance of motor. For this purpose, two different artificial neural networks have been suggested replacing the optimal switching vector selection and flux sector determination process of conventional direct torque control method. Matlab/Simulink based numerical simulations have been carried out to compare motor performances with conventional control structure and proposed artificial neural network based structure. It has been observed that the dynamic response of motor is faster and torque ripple and the controller complexity of the conventional control system has been reduced with the proposed technique.
SENSORLESS VECTOR CONTROL OF BLDC USING EXTENDED KALMAN FILTER sipij
This Paper mainly deals with the implementation of vector control technique using the brushless DC motor
(BLDC). Generally tachogenerators, resolvers or incremental encoders are used to detect the speed. These
sensors require careful mounting and alignment, and special attention is required with electrical noises. A
speed sensor need additional space for mounting and maintenance and hence increases the cost and size of
the drive system. These problems are eliminated by speed sensor less vector control by using Extended
Kalman Filter and Back EMF method for position sensing. By using the EKF method and Back EMFmethod, the sensor less vector control of BLDC is implemented and its simulation using MATLAB/SIMULINK and hardware kit is implemented.
Direct Torque Control of Four Switch Three Phase Inverter Fed Induction Motor...IAES-IJPEDS
This paper presents sensorless speed control of induction motor (IM) using four switch three phase inverter (FSTPI) with direct torque and flux control (DTFC). The proposed sensorless DTFC system consists of an adaptive observer of rotor flux to accurately estimate stator resistance and speed simultaneously, without affecting drive performances. The switching technique for DTFC of IM using FSTPI in low power application is based on the principle of similarity between FSTPI and SSTPI (six switch three phase inverter), where the αβ plan is divided into 6 sectors and the formation of the voltage space vector is done in the same way as for SSTPI by using effective (mean) vectors. This approach allows using the well-known established switching table of SSTPI for FSTPI. The simulation results indicates that the sensorless speed control of FSTPI fed IM with DTFC and adaptive observer provides accurate estimate, good trajectory tracking with different dynamics performance. The experimental results verify the effectiveness of the proposed method at different operating points.
FLC-Based DTC Scheme for a New Approach of Two-Leg VSI Fed Induction MotorIJERA Editor
A new Direct Torque Control (DTC) strategy for Induction Motor (IM) drive fed by a two leg three phase
inverter (i.e., Four switches are used in VSI) was proposed in this paper. The proposed methodology is based on
the emulation of operation of the conventional Six-switch three phase inverter. The combination of four
unbalanced voltage vectors is generated by the two-leg three phase inverter, approaching to the synthesis of the
six balanced voltage vectors of the conventional DTC. This approach has been implemented in the design of the
vector selection table of the proposed DTC strategy. Further, Fuzzy Logic Controller (FLC) is proposed in the
speed controller for the improvement of torque ripples. Convention DTC with Six Switch three phase VSI, twoleg
three phase VSI with PI and Fuzzy Controller are implemented using MATLAB/SIMULINK. Simulation
results have shown that the proposed DTC strategy, two-leg inverter fed IM drive revealed an improved
performance.
Fuzzy logic based direct torque control of induction motor with space vector ...ijscai
The induction motors have wide range of applications for due to its well-known advantages like brushless
structures, low costs and robust performances. Over the past years, many kind of control methods are
proposed for the induction motors and direct torque control has gained huge importance inside of them due
to fast dynamic torque responses and simple control structures. However, the direct torque control method
has still some handicaps against the other control methods and most of the important of these handicaps is
high torque ripple. This paper suggests a new approach, Fuzzy logic based space vector modulation, on
the direct torque controlled induction motors and aim of the approach is to overcome high torque ripple
disadvantages of conventional direct torque control. In order to test and compare the proposed direct
torque control method with conventional direct torque control method simulations, in Matlab/Simulink,
have been carried out in different working conditions. The simulation results showed that a significant
improvement in the dynamic torque and speed responses when compared to the conventional direct torque
control method.
This paper presents the comparative performances of Indirect Field Oriented Control (IFOC) for the three-phase induction motor. Recently, the interest of widely used the induction motor at industries because of reliability, ruggedness and almost free in maintenance. Thus, the IFOC scheme is employed to control the speed of induction motor. Therefore, P and PI controllers based on IFOC approach are analyzed at differences speed commands with no load condition. On the other hand, the PI controller is tuned based on Ziegler-Nichols method by using PSIM software which is user-friendly for simulations, design and analysis of motor drive, control loop and the power converter in power electronics studies. Subsequently, the simulated of P controller results are compared with the simulated of PI controller results at difference speed commands with no load condition. Finally, the simulated results of speed controllers are compared with the experimental results in order to explore the performances of speed responses by using IFOC scheme for three-phase induction motor drives.
This paper presents a study concerning a sensorless vector control of an induction machine fed by a voltage source inverter. The aim is to provide a scheme to control the speed and the rotor flux using a sensorless integral backstepping control approach. The rotor speed estimation is done by an observer using the model reference adaptive system (MRAS) technique whereas the nonlinear backstepping observer is used to get the rotor flux. The main objective is to achieve a robust control, adaptive and efficient, which will allow us to test and evaluate the performance of the proposed observer, combined with a sensorless control of the induction machine. Tests and validation are done using numerical simulations with MATLAB/SIMULINK-PSB (Power System Block set) toolbox. The results show good performance in terms of robustness regarding machine parameter variations and show the excellent quality of the control law associated with the observer, despite the observability problems when the machine operates at low speed.
Performance Analysis of a DTC and SVM Based Field- Orientation Control Induct...IJPEDS-IAES
This study presents a performance analysis of two most popular control strategies for Induction Motor (IM) drives: direct torque control (DTC) and space vector modulation (SVM) strategies. The performance analysis is done by applying field-orientation control (FOC) technique because of its good dynamic response. The theoretical principle, simulation results are discussed to study the dynamic performances of the drive system for individual control strategies using actual parameters of induction motor. A closed loop PI controller scheme has been used. The main purpose of this study is to minimize ripple in torque response curve and to achieve quick speed response as well as to investigate the condition for optimum performance of induction motor drive. Depending on the simulation results this study also presents a detailed comparison between direct torque control and space vector modulation based field-orientation control method for the induction motor drive.
A Novel Optimal PI Parameter Tuning Strategy to Improve Constant Switching Pe...IJPEDS-IAES
This paper presents a novel method of optimal Propotional-Intergral (PI)
controller’s parameter tuning strategy in-order to improve the constant
switching performance of 3-phase direct torque control (DTC) shceme. The
DTC sheme is acknowledged to provide fast decoupled control over the
torque output and stator flux via a simple control structure. However, DTC
sheme has two major downsides, which are the inconsistent inverter
switching frequency and high torque output ripple. The main reason that
contributes to these tribulations is the usage of hysteresis comparators in
order to control the output torque. The realization of PI based controller
method as replacement of hyterisis controller in DTC system able to provide
significant solutions to over come the fall back while retaining the simple
control structure of conventional DTC. The combination usage of higher
sampling controller DS1004 and also 3-level cascaded H-bridge multilevel
inverters (CHMI) in this system can further minimize the output torque ripple
by providing higher resolution with lower digital error and greater number of
vectors. This paper presents detail explanation and calculation of optimal PI
parameter tuning strategy consecutively to enhance the performance of 3-
level DTC system. In order to verify the feasibility of the proposed method
experimentation, the proposed method is compared with convention DTC
system via simulation and experiment results.
Experimental Evaluation of Torque Performance of Voltage and Current Models u...IJPEDS-IAES
In this paper, two kinds of observers are proposed to investigate torque estimation. The first one is based on a voltage model represented with a low- pass filter (LPF); which is normally used as a replacement for a pure integrator to avoid integration drift problem due to dc offset or measurement error. The second estimator used is an extended Kalman filter (EKF) as a current model, which puts into account all noise problems. Both estimation algorithms are investigated during the steady and transient states, tested under light load, and then compared with the measured mechanical torque. In all conditions, it will be shown that the torque estimation error for EKF has remained within narrower error band and yielded minimum torque ripples when compared to LPF estimation. This motivates the use of EKF observer in high performance control drives of induction machines for achieving improved torque response.
RANDOM PULSEWIDTH MODULATION TECHNIQUE FOR A 4-LEVEL INVERTERIAEME Publication
Random Pulse Width Modulation (RPWM) technique for a 4-level inverter in open-end winding induction motor configuration is proposed i n this paper. Reference voltage space vector is randomly sampled and it is realized in average sens e by switching its three nearest vectors. Switching frequency is randomly varied within the bounds to get randomly s paced samples. The method requires no sector identification. The refer encephasor is converted into a vector lying in the basic 2-level inverter to calculate switching time vectors. The proposed scheme is implemented and experimental results are presented for a dual inverter fed 4-level open-end winding induction motor drive using DSP platform, TMS 320LF2407A.
Control of Four Switch Three Phase Inverter Fed Induction Motor Drives Based ...IJPEDS-IAES
This paper presents sensorless position and speed control for a four-switch three-phase inverter (FSTPI) fed induction motor drive. Accurate knowledge of stator resistance is of utmost importance for correct operation of a number of speed sensorless induction motor control schemes in the low speed region. Since stator resistance inevitably varies with operating conditions, stable and accurate operation at near-zero speed requires an appropriate identification algorithm for the stator resistance. The paper proposes such an identification algorithm, which is developed for the rotor flux based model reference adaptive system (MRAS) type of the speed estimator in conjunction with a rotor flux oriented control scheme. In this speed estimation method only one (out of the two available) degree of freedom is utilized for speed estimation. It is utilize the second available degree of freedom as a mean for adapting the stator resistance. The parallel stator resistance and rotor speed identification algorithm is developed in a systematic manner, using Popov’s hyper stability theory. It increases the complexity of the overall control system insignificantly and enables correct speed estimation and stable drive operation at near-zero speeds. The proposed speed and position estimator with parallel stator resistance identification for FSTPI fed induction motor at very low speed under high load operation is verified by simulation and experimental results. The results show the robustness of the proposed method with FSTPI.
In a Power plant with a Distributed Control System ( DCS ), process parameters are continuously stored in
databases at discrete intervals. The data contained in these databases may not appear to contain valuable
relational information but practically such a relation exists. The large number of process parameter values
are changing with time in a Power Plant. These parameters are part of rules framed by domain experts for
the expert system. With the changes in parameters there is a quite high possibility to form new rules using
the dynamics of the process itself. We present an efficient algorithm that generates all significant rules
based on the real data. The association based algorithms were compared and the best suited algorithm for
this process application was selected. The application for the Learning system is studied in a Power Plant
domain. The SCADA interface was developed to acquire online plant data.
APPLYING AN ARABIC CONVERSATIONAL AGENT IN THE JORDANIAN E-GOVERNMENTijcsit
This paper discusses a prototype idea of applying a Conversational Agent (CA) to be embedded into the Jordanian E-government websites. The Conversational Agent is a smart system used to handle natural conversations between user and machine. A Jordanian citizen facing struggles when he/she want to apply for a service through the E-government portal.In addition the Jordanians struggling when searched for a
piece of information (for example the needed documents for a specific service) inside the E-government websites. This struggling comes from number of reasons such as the needed knowledge that the user could have to deal with such services and the big number of links that the user must visitto achieve his/her target.In addition, the Jordanian E-Government websites does not meet the users’ requirements in their design.
Instead, this paper proposes the idea of applying a prototype called CA into those websites as a general help desk automated service to save the Jordanians time and effort. Simply, the user will chat with the proposed CA with what he/she coming to do through the targeted website using a text based Arabic conversations. The CA’s responses might be the exact needed link or the targeted information. Such a proposed service will strength the Jordanian E-government platform especially for accessibility and usability factors and as to best of our knowledge, no country has been applied it before.
A S URVIVABILITY M ODEL FOR S AUDI ICT S TART - UPSijcsit
nnovation and entrepreneurship are critical elements in the transition to the knowledge-based economy
and future competition. Unfortunately, innovation tends to
b
e absent in Arab states for many reasons. To
promote innovation in Saudi Arabia, for instance, it is necessary to support inventors’ ideas to turn
inventions into start-up companies, which are companies in their early stage. At the same time, it seems
that there is a need for more academic research to study the success factors of Saudi information and
communication technology (ICT) start-up companies. ICT start-ups are important to the economy because
they are needed for the progress of all industries. Therefore, this study will identify the factors that lead to
successful ICT start-up projects. Then, it will develop a model for the best practices in the interplay among
the defined factors that will increase the opportunity to initiate successful start-ups. This research involves
a factor analysis study based on a quantitative method to measure the interdependences among the success
factors for ICT start-ups. The identified factors are verified using a sample of Saudi
start-up companies.
The study will contribute to enhancing the technological content to diversify the Saudi economy in order to
prepare for the post-oil era
Evaluation of employee performance is an important element in enhancing the quality of the work and
improves employees’ motivation to perform well. It also presents a basis for upgrading and enhancing of
an organization. Periodical employees’ performance evaluation in an organization assists management to
recognize its strengths and weaknesses.
This paper presents a design and implementation of a performance appraisal system using the fuzzy logic.
In addition to the normal process of performance evaluation modules, the system contains step by step
inference engine processes. These processes demonstrate several calculation details in relations
composition and aggregation methods such as min operator, algebraic product, sup-min and sup-product.
The system has foundation to add-on analysis module to analyze and report the final result using various
similarity measures. MS Access database was used to maintain the data, build the inference logic and
develop all setting user interfaces.
AN INVESTIGATION OF THE ENERGY CONSUMPTION BY INFORMATION TECHNOLOGY EQUIPMENTSijcsit
The World Wide Web and the rise of servers and PC's data centers have become a major position in the
overall power consumption of the world. In order to prevent global warming and ensuing disasters, already
Internet-service providers, hosting providers on green power have changed. Even household energy
suppliers offer green electricity from renewable energy such as wind, solar, biomass and hydro, which
emits no carbon dioxide, to stand against global warming. Only a global change for the information
technology can prevent the global-warming. The switch to renewable energy is the beginning of our future
and must be pursued as well as the research and development in information and communication
technology.
A rule based approach towards detecting human temperamentijcsit
This paper presented a rule based system for detecting human temperament.. The system was developed to
provide support for an expert psychologist in properly predicting the temperament of an individual as well
as given advice to the user. The system does this by following specified rules. Of this, we have deduced
some features that makes up known temperament types from which the system can accurately classify the
user‘s temperament based on the person‘s characters. Also, our work is solely limited to temperament, any
expert advice sought from and given by the system is limited to this scope.
Design and Implementation of Repair-aware Test Flow for Multi-Memoryijcsit
A complex SoC typically consists of numerous of memories in today's digital systems. This paper presents a test/ repair flow based on memory grouping strategy and a revised distributed BIST structure for complex SoC devices. A gated selecting method is added to the distributed BIST structure. Also, this paper for the first time proposes a robust post repair stage based on BIRA and memory grouping in test flow. Simulation results by mathematical method show that the proposed test flow has achieved a significant increase in yield of memories.
T OWARDS A S YSTEM D YNAMICS M ODELING M E- THOD B ASED ON DEMATELijcsit
If System Dynamics (SD) models are constructed based
solely on decision makers' mental models and u
n-
derstanding of the context subject to study, then the resulting systems must necessarily bear some d
e
gree of
deficiency due to the subjective, limited, and internally inconsistent mental models which led to t
he conce
p-
tion of these systems. As such, a systematic method for constructing SD models could be esse
n
tially helpful
in overcoming the biases dictated by the human mind's limited understanding and conceptualization of
complex systems. This paper proposes a
novel combined method to su
p
port SD model construction. The
classical Dec
i
sion Making Trial and Evaluation Laboratory (DEMATEL) technique is used to define causal
relationships among variables of a system, and to construct the corresponding Impact Relatio
n Maps
(IRMs). The novelty of this paper stems from the use of the resulting total influence m
a
trix to derive the
system dynamic's Causal Loop Diagram (CLD) and then define variable weights in the stock
-
flow chart
equations. This new method allows to overc
ome the subjectivity bias of SD
mode
ling while projecting D
E-
MATEL in a more d
y
namic simulation environment, which could significantly improve the strategic choices
made by an
a
lysts and policy makers
Survey of the Euro Currency Fluctuation by Using Data Miningijcsit
Data mining or Knowledge Discovery in Databases (KDD) is a new field in information technology that emerged because of progress in creation and maintenance of large databases by combining statistical and artificial intelligence methods with database management. Data mining is used to recognize hidden patterns and provide relevant information for decision making on complex problems where conventional methods are inecient or too slow. Data mining can be used as a powerful tool to predict future trends and behaviors, and this prediction allows making proactive, knowledge-driven decisions in businesses. Since the automated prospective analyses offered by data mining move beyond the analyses of past events provided by retrospective tools, it can answer the business questions which are traditionally time consuming to resolve. Based on this great advantage, it provides more interest for the government, industry and commerce. In this paper we have used this tool to investigate the Euro currency fluctuation.For this investigation, we have three different algorithms: K*, IBK and MLP and we have extracted.Euro currency volatility by using the same criteria for all used algorithms. The used dataset has
21,084 records and is collected from daily price fluctuations in the Euro currency in the period
of10/2006 to 04/2010.
COMPARING OF SWITCHING FREQUENCY ON VECTOR CONTROLLED ASYNCHRONOUS MOTORijscai
Nowadays, asynchronous motors have wide range use in many industrial applications. Field oriented
control (FOC) and direct torque control (DTC) are commonly used methods in high performance vector
control for asynchronous motors. Therefore, it is very important to identify clearly advantages and
disadvantages of both systems in the selection of appropriate control methods for many industrial
applications. This paper aims to present a new and different perspective regarding the comparison of the
switching behaviours on the FOC and the DTC drivers. For this purpose, the experimental studies have
been carried out to compare the inverter switching frequencies and torque responses of the asynchronous
motor in the FOC and the DTC systems under different working conditions. The dSPACE 1103 controller
board was programmed with Matlab/Simulink software. As expected, the experimental studies showed that
the FOC controlled motors has a lessened torque ripple. On the other hand, the FOC controlled motor
switching frequency
A NEW FUZZY LOGIC BASED SPACE VECTOR MODULATION APPROACH ON DIRECT TORQUE CON...csandit
The induction motors are indispensable motor types for industrial applications due to its wellknown
advantages. Therefore, many kind of control scheme are proposed for induction motors
over the past years and direct torque control has gained great importance inside of them due to
fast dynamic torque response behavior and simple control structure. This paper suggests a new
approach on the direct torque controlled induction motors, Fuzzy logic based space vector
modulation, to overcome disadvantages of conventional direct torque control like high torque
ripple. In the proposed approach, optimum switching states are calculated by fuzzy logic
controller and applied by space vector pulse width modulator to voltage source inverter. In
order to test and compare the proposed DTC scheme with conventional DTC scheme
simulations, in Matlab/Simulink, have been carried out in different speed and load conditions.
The simulation results showed that a significant improvement in the dynamic torque and speed
responses when compared to the conventional DTC scheme.
CONTROL OF AN INDUCTION MOTOR WITH DOUBLE ANN MODEL BASED DTCcsandit
Direct torque control (DTC) is preferably control method on high performance control of induction motors due to its dvantages such as fast dynamic response, simple and robust control structure. However, high torque and current ripples are mostly faced problems in this control method. This paper presents artificial neural network (ANN) based approach to the DTC method to overcome mentioned problems. In the study, by taking a different perspective to ANN and DTC integration, two different ANN models have been designed, trained and implemented. The first ANN model has been used for switch selecting process and the second one has been used for sector determine process. Matlab/Simulink model of the proposed ANN based DTC method has created in order to compare with the conventional DTC and the proposed DTC
methods. The simulation studies have proved that the induction motor torque and current
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
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.
The induction motors are indispensable motor types for industrial applications due to its wellknown advantages. Therefore, many kind of control scheme are proposed for induction motors over the past years and direct torque control has gained great importance inside of them due to fast dynamic torque response behavior and simple control structure. This paper suggests a new approach on the direct torque controlled induction motors, Fuzzy logic based space vector
modulation, to overcome disadvantages of conventional direct torque control like high torque ripple. In the proposed approach, optimum switching states are calculated by fuzzy logic
controller and applied by space vector pulse width modulator to voltage source inverter. In order to test and compare the proposed DTC scheme with conventional DTC scheme
simulations, in Matlab/Simulink, have been carried out in different speed and load conditions. The simulation results showed that a significant improvement in the dynamic torque and speed responses when compared to the conventional DTC scheme.
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.
This paper deal with the problem in speed controller for Indirect Field Oriented Control of Induction Motor. The problem cause decrease performance of Induction Motor where it widely used in high-performance applications. In order decrease the fault of speed induction motor, Takagi-Sugeno type Fuzzy logic control is used as the speed controller. For this, a model of indirect field oriented control of induction motor is built and simulating using MATLAB simulink. Secondly, error of speed and derivative error as the input and change of torque command as the output for speed control is applied in simulation. Lastly, from the simulation result overshoot is zero persent, rise time is 0.4s and settling time is 0.4s. The important data is steady state error is 0.01 percent show that the speed can follow reference speed. From that simulation result illustrate the effectiveness of the proposed approach.
LIGHTWEIGHT MOBILE WEB SERVICE PROVISIONING FOR THE INTERNET OF THINGS MEDIATIONijujournal
Emerging sensor-embedded smartphones motivated the mobile Internet of Things research. With the
integrated embedded hardware and software sensor components, and mobile network technologies,
smartphones are capable of providing various environmental context information via embedded mobile
device-hosted Web services (MWS). MWS enhances the capability of various mobile sensing applications
such as mobile crowdsensing, real time mobile health monitoring, mobile social network in proximity and
so on. Although recent smartphones are quite capable in terms of mobile data transmission speed and
computation power, the frequent usage of high performance multi-core mobile CPU and the high speed
3G/4G mobile Internet data transmission will quickly drain the battery power of the mobile device.
Although numerous previous researchers have tried to overcome the resource intensive issues in mobile
embedded service provisioning domain, most of the efforts were constrained because of the underlying
resource intensive technologies. This paper presents a lightweight mobile Web service provisioning
framework for mobile sensing which utilises the protocols that were designed for constrained Internet of
Things environment. The prototype experimental results show that the proposed framework can provide
higher throughput and less resource consumption than the traditional mobile Web service frameworks.
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.
DTC Scheme for a Four-Switch Inverter-Fed PMBLDC Motor Emulating the Six-Swit...IJRST Journal
The paper deals with the direct torque control (DTC) of brushless DC (BLDC) motor drives fed by four-switch three phase inverters (FSTPI) rather than six-switch inverters (SSTPI) in conventional drives. For any three phase inverter require six switches, but these switches are reduced to four. This reduction of power switches from six to four improves the reliability of the inverter, size of the inverter is reduced and cost of the inverter is also reduces. The FSTPI could be regarded as a reconfigured topology of the SSTPI in case of a switch/leg failure which represents a crucial reliability benefit for many applications especially in electric and hybrid propulsion systems. The DTC of FSTPI-fed BLDC motor drives is treated considering two strategies, such as: 1) DTC-1: a strategy inspired from the one intended to SSTPI-fed BLDC motor drives; 2) DTC-2: a strategy that considers a dedicated vector selection subtable in order to independently control the torques developed by the phases connected to the FSTPI legs during their simultaneous conduction. The operational principle of the four-switch BLDC motor drive and the developed control scheme are theoretically analyzed and the performance is demonstrated by simulation.
Performance Characteristics of Induction Motor with FielIJPEDS-IAES
With development of power electronics and control Theories, the AC motor
control becomes easier. So the AC motors are used instead of the DC motor
in the drive applications. With this development, a several methods of control
are invented. The field oriented control and direct torque control are from the
best methods to control the drive systems. This paper is compared between
the field oriented control and direct torque control to show the advantages
and disadvantages of these methods of controls. This study discussed the
effects of these methods of control on the total harmonic distortion of the
current and torque ripples. This occurs through study the performance
characteristics of the AC motor. The motor used in this study is an induction
motor. This study is simulated through the MATLAB program.
Fuzzy controlled dtc fed by a four switch inverter for induction motoreSAT Journals
Abstract
Direct Torque Control of induction motor fed drives has become popular and widely used in industries due to fast and good
torque response. Induction motors (IM) are simple in construction and are less sensitive to the motor parameters compared to
other vector control methods. The conventional DTC is based on flux and torque hysteresis controllers. Induction motor is fed
from a Four Switch Inverter generating the voltage vectors of the Six Switch Inverter by reconfiguration. Applying the most
optimized voltage vector that produce fastest dynamic torque response during transient states. Fuzzy logic concept is a most
efficient artificial integilence method which has high application in electric motor drives. A method to achieve fastest dynamic
performance by modifying the two leg inverter fed DTC of induction motor based on Fuzzy Logic Concept is used here. This paper
presents a rule-based fuzzy logic controller scheme designed and applied for the speed control of an induction motor fed from a
four switch three phase inverter emulating the six switch three phase inverter. Due to the usage of the Fuzzy logic concept, the
reliability, efficiency and performance of ac drive increases. Initial torque peak and torque ripple are minimized in the four switch
three phase inverter based DTC using Fuzzy Logic.
Key Words: Direct Torque Control , Four Switch/Six Switch Three Phase Inverter, Fuzzy Logic, Induction motor(IM).
A Novel Direct Torque Control for Induction Machine Drive System with Low Tor...IAES-IJPEDS
The conventional Direct Torque Control (DTC) is known to produce a quick and robust response in AC drives. However, during steady state, stator flux and electromagnetic torque which results in incorrect speed estimations and acoustical noise. A modified Direct Torque Control (DTC) by using Space Vector Modulation (DTC-SVM) for induction machine is proposed in this paper. Using this control strategy, the ripples introduced in torque and flux are reduced. This paper presents a novel approach to design and implementation of a high perfromane torque control (DTC-SVM) of induction machine using Field Programmable gate array (FPGA). The performance of the proposed control scheme is evaluated through digital simulation using Matlab\Simulink and Xilinx System Generator. The simulation results are used to verify the effectiveness of the proposed control strategy.
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.
A NEW APPROACH TO DTC METHOD FOR BLDC MOTOR ADJUSTABLE SPEED DRIVEScscpconf
This paper proposes a new approach to direct torque control (DTC) method for brushless direct current (BLDC) motor drives. In conventional DTC method, two main reference parameters are used as: flux and torque. In this paper, the new approach has been proposed to improve the BLDC motor dynamic performance. A main difference from the conventional method of it was that only one reference parameter (speed) was used to control the BLDC motor and the second control parameter (flux) was obtained from speed error through the proposed control algorithm. Thus, the DTC performance has been especially improved on systems which need variable speed and torque during operation, like electric vehicles. The dynamic models of the BLDC and the DTC method have been created on Matlab/Simulink. The proposed method has been confirmed and verified by the dynamic simulations on different working conditions.
Slack (or Teams) Automation for Bonterra Impact Management (fka Social Soluti...Jeffrey Haguewood
Sidekick Solutions uses Bonterra Impact Management (fka Social Solutions Apricot) and automation solutions to integrate data for business workflows.
We believe integration and automation are essential to user experience and the promise of efficient work through technology. Automation is the critical ingredient to realizing that full vision. We develop integration products and services for Bonterra Case Management software to support the deployment of automations for a variety of use cases.
This video focuses on the notifications, alerts, and approval requests using Slack for Bonterra Impact Management. The solutions covered in this webinar can also be deployed for Microsoft Teams.
Interested in deploying notification automations for Bonterra Impact Management? Contact us at sales@sidekicksolutionsllc.com to discuss next steps.
Accelerate your Kubernetes clusters with Varnish CachingThijs Feryn
A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
This presentation was delivered at K8SUG Singapore. See https://feryn.eu/presentations/accelerate-your-kubernetes-clusters-with-varnish-caching-k8sug-singapore-28-2024 for more details.
The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
Smart TV Buyer Insights Survey 2024 by 91mobiles.pdf91mobiles
91mobiles recently conducted a Smart TV Buyer Insights Survey in which we asked over 3,000 respondents about the TV they own, aspects they look at on a new TV, and their TV buying preferences.
Search and Society: Reimagining Information Access for Radical FuturesBhaskar Mitra
The field of Information retrieval (IR) is currently undergoing a transformative shift, at least partly due to the emerging applications of generative AI to information access. In this talk, we will deliberate on the sociotechnical implications of generative AI for information access. We will argue that there is both a critical necessity and an exciting opportunity for the IR community to re-center our research agendas on societal needs while dismantling the artificial separation between the work on fairness, accountability, transparency, and ethics in IR and the rest of IR research. Instead of adopting a reactionary strategy of trying to mitigate potential social harms from emerging technologies, the community should aim to proactively set the research agenda for the kinds of systems we should build inspired by diverse explicitly stated sociotechnical imaginaries. The sociotechnical imaginaries that underpin the design and development of information access technologies needs to be explicitly articulated, and we need to develop theories of change in context of these diverse perspectives. Our guiding future imaginaries must be informed by other academic fields, such as democratic theory and critical theory, and should be co-developed with social science scholars, legal scholars, civil rights and social justice activists, and artists, among others.
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Builder.ai Founder Sachin Dev Duggal's Strategic Approach to Create an Innova...Ramesh Iyer
In today's fast-changing business world, Companies that adapt and embrace new ideas often need help to keep up with the competition. However, fostering a culture of innovation takes much work. It takes vision, leadership and willingness to take risks in the right proportion. Sachin Dev Duggal, co-founder of Builder.ai, has perfected the art of this balance, creating a company culture where creativity and growth are nurtured at each stage.
Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
Key Trends Shaping the Future of Infrastructure.pdfCheryl Hung
Keynote at DIGIT West Expo, Glasgow on 29 May 2024.
Cheryl Hung, ochery.com
Sr Director, Infrastructure Ecosystem, Arm.
The key trends across hardware, cloud and open-source; exploring how these areas are likely to mature and develop over the short and long-term, and then considering how organisations can position themselves to adapt and thrive.
To Graph or Not to Graph Knowledge Graph Architectures and LLMs
Comparing of switching frequency on vector controlled asynchronous motor
1. International Journal on Soft Computing, Artificial Intelligence and Applications (IJSCAI), Vol.3, No. 3/4, November 2014
COMPARING OF SWITCHING FREQUENCY ON VECTOR
CONTROLLED ASYNCHRONOUS MOTOR
Yılmaz Korkmaz1, Fatih Korkmaz2, Ismail Topaloglu2, Hayati Mamur2
1 Faculty of Technology, Department of Electrical-Electronic Engineering,
Gazi University, Ankara, Turkey
2 Faculty of Engineering, Department of Electrical-Electronic Engineering,
Çankırı Karatekin University, Çankırı, Turkey
ABSTRACT
Nowadays, asynchronous motors have wide range use in many industrial applications. Field oriented
control (FOC) and direct torque control (DTC) are commonly used methods in high performance vector
control for asynchronous motors. Therefore, it is very important to identify clearly advantages and
disadvantages of both systems in the selection of appropriate control methods for many industrial
applications. This paper aims to present a new and different perspective regarding the comparison of the
switching behaviours on the FOC and the DTC drivers. For this purpose, the experimental studies have
been carried out to compare the inverter switching frequencies and torque responses of the asynchronous
motor in the FOC and the DTC systems under different working conditions. The dSPACE 1103 controller
board was programmed with Matlab/Simulink software. As expected, the experimental studies showed that
the FOC controlled motors has a lessened torque ripple. On the other hand, the FOC controlled motor
switching frequency has about 65-75% more than the DTC controlled under both loaded and unloaded
working conditions.
KEYWORDS
Asynchronous motor; vector control; motor drives; switching frequency
1. INTRODUCTION
For many years, asynchronous motors have wide range use in industrial applications due to its
simple and robust structure and low costs when compared with dc motors. Furthermore, we have
better high performance control options now due to development of power electronics in the last
few decades. There are two noted control methods in high performance control of asynchronous
motors named as: FOC and DTC.
Blaschke proposed the FOC in the 1970s. The FOC was unique and only option that we had on
asynchronous motors high performance control until 1980s that the DTC was introduced by
Takahashi. Since that day, there have been continual discussions and questions about that: Which
one has the best performance on asynchronous motors vector control? [1-3].
The main idea of vector control methods is the control of motor flux and torque components
separately like DC motors. The main difference between two methods is that the FOC controls by
a rotor or stator field orientation, while the DTC controls by a stator field observation [4]. So, the
structural differences in the both control methods are that the FOC uses park transformation, more
machine parameters, and current regulators, while the DTC uses Clarke transformation, less
DOI :10.5121/ijscai.2014.3402 19
2. International Journal on Soft Computing, Artificial Intelligence and Applications (IJSCAI), Vol.3, No. 3/4, November 2014
machine parameters, and any current regulators. Thus, comparative studies between the two
methods show that the DTC is simplicity, a fast dynamic response, and robust against to
parameter changes. Despite all these advantages, the DTC also has some handicaps: the most
important of them being high torque and current ripples. Evidently, all users have to take into
account all these advantages and disadvantages when deciding on which method they will use on
designed system [5]. There are some comparative studies regarding both comparison of both the
methods, which address the motors speed and torque behaviours. Thanks to this research, it is
now known that despite a high torque ripple, the DTC has a fast dynamic response [6-7].
In this paper, a new and different perspective has been presented regarding the comparison of the
FOC and the DTC drivers. The voltage source inverter switching frequencies has been compared
on both the FOC and the DTC systems. There is no doubt about the importance of switching
frequency on power electronic systems because its directly affects switching losses and it means
also affects indirectly the efficiency of the drivers. Experimental studies have been carried out to
compare switching frequencies and the dSpace 1103 controller board has been programmed with
Matlab/Simulink.
20
2. FOC AND DTC METHODS
The FOC is mostly used to control the speed of the motor, not control of the moment, due to its
low level sensitivity [8].
In the FOC, the parameters of the motor have to be turned in a d-q reference frame, which
consider turns in a synchronous speed (park transformation). Thus, the position of the rotor flux
has to be well determined for the success of transformation. In the determining the process of the
rotor flux position two basic approaches are used.
Using of flux sensors is the first approach to determine the rotor flux position while to measure
the rotor position with an incremental encoder and calculate the angle between the axis of the
rotor and the flux, is the second one. Eq. 1 and Eq. 2, describes the calculation of the stator
current d-q components.
*
T L
2
qs L
=
r
m
e
r
p
i
*
* 2
3
l
(1)
r
m
ds L
i
*
* l
= (2)
*
qs i and *
ds i are the stator current d-q components reference values, *
r l is the rotor flux reference
value, and m L is the mutual inductance, r L is rotor inductance and p is motor pole pairs value
in these equations. The stator three phase currents obtained by using the transformation matrix
which is given in Eq. 3.
3. International Journal on Soft Computing, Artificial Intelligence and Applications (IJSCAI), Vol.3, No. 3/4, November 2014
21
6. i
i
*
q
*
0
*
a
*
b
*
1
2
2
3
sin
2
2
3
cos
1
3
sin
3
cos
cos sin 1
i
i
d
c
p
q
p
q
p
q
p
q
q q
(3)
In Eq. 3., q indicates the rotor angular position, and can be obtained from the integration of the
sum of the rotor angular speed ( r w ) and the sleep angular speed ( sl w ) as given in Eq. 4.
( )dt r sl q =
w +w . (4)
and the sleep angular speed is obtained from Eq. 5.
*
L R
l
m r
w = (5)
sl i
* qs
L
r r
The FOC control block diagram is created by using Eq.1- Eq.5 and is shown in Fig. 1[9].
Fig. 1. Simulink block diagram of the FOC controller
The DTC algorithm controls the stator flux and the torque with using measured currents and
voltages.
Instantaneous values of the flux and the torque can be obtained by using the transformation of the
measured currents and the voltages of the motor. The stator flux is calculated as given in Eq.5-7
in a stationary reference frame [10].
(V R i )dt s =
− a a a l (6)
(V R i )dt s =
− b b b l (7)
7. International Journal on Soft Computing, Artificial Intelligence and Applications (IJSCAI), Vol.3, No. 3/4, November 2014
22
2 2
a b l = l +l (8)
Where, a l - b l stator flux, a i - b i stator current, a V - a V stator voltage a − b components,
s R stator resistance. Motor torque can be calculated as given in Eq.9.
3
( ) a b b a T p l i l i e = −
2
(9)
Where, p is the motor pole pairs. The stator flux vector region is an important parameter for the
DTC, and it can be calculated as given in Eq.10.
q 1 tan (10)
l
l l
= −
b
a
The torque and flux errors are obtained by comparing the reference and observed values and than
the errors are converted to control signals by hysteresis comparators. The switching table is used
to obtain the optimum switching inverter states, and it determines the states by using the
hysteresis comparators outputs and the flux region data[11]. The schematic view of the
experimental setup is given in Fig. 2.
Fig. 2. Schematic view of the experimental setup
3. EXPERIMENTAL STUDIES
Experimental tests have been carried out in order to compare the switching frequency between the
DTC and the FOC systems, and the dSpace 1103 DSP (Digital Signal Processor) board has been
programmed in the Matlab-Simulink Real-Time-Workshop environment for tests.
A new block has been created to compare the switching frequency on both systems. The inverter
switching frequency has been obtained by the addition of the arms switching frequencies, and
8. International Journal on Soft Computing, Artificial Intelligence and Applications (IJSCAI), Vol.3, No. 3/4, November 2014
then dividing the total by three. However, especially in the DTC, the switching frequency has a
wide range, so the average switching frequency has been calculated with a different sampling
time (100 ms) in the frequency measurement block to obtain healthy comparable results.
The results of the experimental tests obtained in this study are for the asynchronous motor of 4
kW and the parameters of the motor, and the experiments are as given below. The motor model is
implemented for the DTC and the FOC methods on the Matlab/Simulink. Different load ranges
have been applied to the asynchronous motor to compare the switching frequencies. The DTC and
the FOC systems have been tested at under no load and loaded (10 N.m.) conditions. The
parameters of the three-phase asynchronous motor, in the SI units: P=4 kW, U=380 V, I=8.2 A,
cos=0.85, 1425 rpm, f=50 Hz, Rs =7.2 .
23
Fig. 3. Torque responses of unloaded DTC controlled motor
Fig. 4. Torque responses of unloaded FOC controlled motor
9. International Journal on Soft Computing, Artificial Intelligence and Applications (IJSCAI), Vol.3, No. 3/4, November 2014
24
Fig. 5. Switching frequencies of unloaded DTC controlled motor
Fig. 6. Switching frequencies of unloaded FOC controlled motor
In the first group of the tests, the motor has been operated as unloaded working conditions. The
motor speed has been set up to 1500 rpm for all experimental tests. The moment and switching
frequency data, which has been calculated within the Simulink blocks, have been obtained by
using the digital-analogue converters of the dSPACE 1103 controller board. The torque response
curves of the motor for the both systems have been given in Figure 3 and Figure 4 for unloaded
working conditions. As expected, it can be clearly seen that the DTC has much torque ripples
when compared FOC.
Figure 5 and Figure 6 show change on the switching frequencies of the motor for both systems.
The switching frequency of the DTC controlled motor has nearly 900 Hz, while the FOC
controlled motor has 1400 Hz. Therefore, it can be stated that the FOC controlled motor
switching frequency has 65% more than the DTC controlled one.
In the second part of tests, the motor has been operated under loaded (10Nm) conditions and
torque and the switching frequency curves of these tests have been given in following figures.
10. International Journal on Soft Computing, Artificial Intelligence and Applications (IJSCAI), Vol.3, No. 3/4, November 2014
25
Fig. 7. Torque responses of loaded DTC controlled motor
Fig. 8. Torque responses of loaded FOC controlled motor
The torque response curves of the motor for the both systems have been given in Figure 7 and
Figure 8 for loaded working conditions. By analyzing the torque responses of the motor, it can
still be stated that the DTC has much torque ripple. Figure 9 and Figure 10 show change on the
switching frequencies of the motor for both systems. The switching frequency of the DTC
controlled motor has approximately 800 Hz, while the FOC controlled motor has 1300 Hz.
Consequently, the FOC controlled motor switching frequency nearly %75 more than DTC
controlled under loaded conditions.
After all the experimental studies, it can be seen that the switching frequency behaviour of the
inverter has close ratio in loaded and unloaded operating conditions, so this shows that the change
of the switching frequency on both systems is independent of the motor load situation. In
addition, it can be accepted that the change in the switching frequency is also independent of the
motor size due to the independency of the load situations.
11. International Journal on Soft Computing, Artificial Intelligence and Applications (IJSCAI), Vol.3, No. 3/4, November 2014
26
Fig. 9. Switching frequencies of loaded DTC controlled motor
Fig. 10. Switching frequencies of loaded FOC controlled motor
4. CONCLUSIONS
Choose of the motor driver can be very important to operate the designed system efficiently when
designing an application which includes electric motors. Addition, many times, it can be difficult
to decide any optimum control method for obtaining high performance regarding to asynchronous
motor drivers. In fact, for the high performance asynchronous motor drivers, we have only two
options: FOC and DTC. This paper deals with to give fair comparison between two vector control
methods for asynchronous motor drives. For this purpose, experimental tests have been realized
to compare of the motor performances on different working conditions. The experimental test
shows that the DTC method is preferable if the fast dynamic performance has primary importance
whereas the FOC method might be a better option when high torque quality is demanded. In
addition, the inverter switching frequencies have been investigated in the FOC and DTC methods
to give a new criterion for the selection of optimum control strategy for asynchronous motor high
performance control. The experimental studies have carried out to compare the switching
frequencies in both methods under different load conditions. As a result, the FOC controlled
motor switching frequency was almost 70% more than the DTC controlled one under loaded and
unloaded working conditions and choosing of the DTC scheme will also provide high energy
efficiency driver if the dynamic performance of the motor has primary importance.
12. International Journal on Soft Computing, Artificial Intelligence and Applications (IJSCAI), Vol.3, No. 3/4, November 2014
27
REFERENCES
[1] V. Bleizgys, A. Baskys and T. Lipinskis, “Induction motor voltage amplitude control technique based
on the motor efficiency observation”, Electronics and Electrical Engineering – Kaunas: Technologija,
2011. – No. 3(109) – P. 89–92.
[2] Blaschke, F., “The Principle of Field Orientation Applied to The New Transvector Closed-Loop
Control System for Rotating Field Machines”, Siemens-Rev.,1972. – Vol. 39 – P. 217–220.
[3] Takahashi, I., Naguchi, T. A., “New Quick-Response and High-Efficiency Control Strategy of an
Induction Motor”, IEEE Transactions on Industry Application,1986. IA-22(5) –P. 820–827.
[4] Liu-Jun; Wang Wan-li, Wang Yang. “Research on FOC and DTC switching control of asynchronous
motor based on parameter estimation”, Automation and Logistics ICAL 2008. IEEE International
Conference, 2008. – P. 1754–1758.
[5] Farasat, M.; Rostami, N.; Feyzi, M. R., “Speed sensorless hybrid field oriented and direct torque
control of induction motor drive for wide speed range applications”, Power Electronic Drive
Systems Technologies Conference (PEDSTC), 2010. – P. 243–248.
[6] Casadei, D.; Profumo, F.; Serra, G.; Tani, A., “FOC and DTC: two viable schemes for induction
motors torque control”, Power Electronics, IEEE Transactions, 2002. –Vol.17– No.5 – P. 779–787.
[7] Wolbank, T.A.; Moucka, A.; Machl, J.L., “A comparative study of field-oriented and direct-torque
control of induction motors reference to shaft-sensorless control at low and zero-speed”, Intelligent
Control, 2002. Proceedings of the 2002 IEEE International Symposium. – P. 391–396.
[8] T. V. Mumcu, I. Aliskan, K. Gulez, G. Tuna, “Reducing Moment and Current Fluctuations of
Induction Motor System of Electrical Vehicles by using Adaptive Field Oriented Control”,
Electronics and Electrical Engineering – Kaunas: Technologija, 2013. – Vol. 19 – No.2 – P. 21–24.
[9] Krishnan, R. Electric Motor Drives // Prentice Hall, P.450 2001.
[10] Fatih Korkmaz, M.Faruk Çakır, smail Topaloglu, Rıza Gürbüz, “Artificial Neural Network Based
DTC Driver for PMSM”, International Journal of Instrumentation and Control Systems (IJICS) Vol.3,
No.1,pp. 1-7 Jan. 2013
[11] Yılmaz Korkmaz, Ismail Topaloglu, Hayati Mamur, Fatih Korkmaz, “An Investigation on Switching
Behaviours of Vector Controlled Induction Motors” Third International Conference on Advanced
Information Technologies Applications (ICAITA-2014) November 7~8, Dubai, UAE, Conference
Proceedings, Vol. 4, Num. 11, P. 13-19, November, 2014