The Nine-Switch Inverter(NSI) is a recently developed dual output converter. It can be used to drive two three-phase loads independently. As a substitute to two separate conventional voltage source inverters, the NSI has been, already, proposed in various industrial applications to reduce the numberof semiconductor switches and its associated energy losses and drive circuitry. On the other hand, the Direct Torque Control(DTC) is a robust control scheme of AC motors, which consist of selecting proper state vectors of a conventional voltage source inverter. The NSI, having a different working principle from the conventional voltage source inverter and taking into account the varying influence of active space vectors on motor’s torque and stator flux, a Direct Torque Control is suggested in this paper to, efficiently, drive two induction motors independently, while minimizing the torque and stator flux ripples of both motors. Simulations results confirm the effectiveness of the proposed algorithm. In addition, application of this newly proposed control scheme in operation of an Electric Vehicule (EV) is demonstrated.
Dual inverter fed induction motor drives provide more advantages in contrast with other multilevel inverter drives. Coupled PWM techniques provide good standard of output voltage than the decoupled PWM techniques for dual inverter configuration. In this paper analysis of open end winding induction motor by coupled random PWM signals and decoupled SVPWM signals was carried out. Induction motor by random PWM technique generate low acoustic noise and electromagnetic interference to near by systems. The performance evaluation of the drive wss implemented in MATLAB/simulink and the results were presented.
Active and Reactive Power control operation of DFIG forWind Power Generation ...IOSR Journals
This document presents a study on controlling the active and reactive power of a doubly fed induction generator (DFIG) for wind power generation using fuzzy logic. It first describes the DFIG system and its vector control scheme using rotor side and grid side converters. It then discusses modeling the DFIG, controlling the rotor side converter using stator flux orientation, controlling the grid side converter using voltage orientation, and designing a fuzzy logic controller. Simulation results show that a fuzzy logic controller combined with a PI controller improves the tracking of active and reactive power references under different operating conditions compared to using just a PI controller. The paper concludes that DFIG performance can be enhanced using a fuzzy tuned PI controller.
This document describes a direct torque control (DTC) scheme for an induction motor that uses a fuzzy logic controller (FLC) to reduce torque ripples. The DTC controls the motor torque and flux by selecting inverter voltage vectors. Typically this results in torque ripples. The FLC is designed to adaptively adjust the bandwidth of the torque hysteresis controller based on changes in motor torque and current over time. This helps minimize torque ripples and improve dynamic response. Simulation results using MATLAB/Simulink confirm that the FLC-based DTC scheme effectively controls the induction motor with reduced torque ripples compared to conventional DTC.
Study On Speed Control of DC MOTOR Using ThyristorIRJET Journal
This document discusses speed control of a DC motor using a thyristor. It first provides background on DC motors and thyristors. It then presents the mathematical model of a separately excited DC motor. Various methods for controlling DC motor speed are described, including armature voltage control, armature resistance control, and flux control. Single phase half wave, full wave, and dual converter drives are introduced as techniques for implementing thyristor-based speed control. A simulation model is presented to observe the effect of varying the firing angle of a single phase full converter on the torque-speed characteristic of the DC motor. The document concludes that thyristor-based drives can effectively control DC motor speed.
Direct torque control of IM using PID controller IJECEIAES
Direct torque control "DTC" technique is one of a high performance control system of an AC motor drive, which was proposed after the vector oriented control scheme during the resent 25 years. It has been developed rapidly for its concise system scheme, transient and dynamic performance. The DTC mechanism consists of voltage vector selection table, two hysteresis comparators and two estimator’s one for stator flux and another for electromagnetic torque. DTC is directly control torque and flux by using Voltage Source Inverter VSI, space vector and stator flux orientation and indirect speed regulated. A several control techniques can be used for improving the torque and flux performance. In this paper, the DTC with Proportional-Integral-Derivative (PID) controller used to improve the starting and dynamic performance of asynchronous motor AM, which gives good torque and flux response, best speed control and also minimize the unacceptable torque ripple. The mathematical model of DTC with PID controller of 3-phase induction motor IM are simulated under MatlabSimulink. Therefore, the DTC based on PID controller has good performance of IM compared to classical DTC for starting, running state and also during change in load.
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.
Close Loop Control of Induction Motor Using Z-Source InverterIJSRD
In this paper a new closed loop control of induction motor fed by a Z – source inverter based on the vector control or field oriented control strategy is presented. Induction motor is supplied by Z – source inverter, in the Z – source inverter the term Z denotes impedance which means a combination of L & C element which are cross connected. The Z-source inverter consists of a unique impedance network (or circuit) to couple the inverter main circuit to the power supply, hence providing great features that cannot be observed in the conventional voltage-source inverter and current-source inverters in which capacitor and inductor are used, respectively.In the field oriented control method or vector control method speed of the induction motor, torque & 3 phase stator current is given to the field oriented controller and gate pulses for the inverter is generated to obtain the desired operation of the induction motor.
Industrial Power Control by Integral Cycle Switching without Generating Harmo...IRJET Journal
This document discusses integral cycle switching control for industrial power control. It begins by introducing integral cycle control and its advantages over traditional phase control, such as introducing fewer harmonics into the power system. It then describes the principle of operation, including connecting the load to the power source for some number of cycles and then disconnecting it for off-cycles. The paper presents the simulation results showing waveforms and harmonic profiles that demonstrate reduced harmonics. It concludes that integral cycle control provides a low-cost and easy to operate method for AC power control with better efficiency and reduced losses compared to traditional phase control approaches.
Dual inverter fed induction motor drives provide more advantages in contrast with other multilevel inverter drives. Coupled PWM techniques provide good standard of output voltage than the decoupled PWM techniques for dual inverter configuration. In this paper analysis of open end winding induction motor by coupled random PWM signals and decoupled SVPWM signals was carried out. Induction motor by random PWM technique generate low acoustic noise and electromagnetic interference to near by systems. The performance evaluation of the drive wss implemented in MATLAB/simulink and the results were presented.
Active and Reactive Power control operation of DFIG forWind Power Generation ...IOSR Journals
This document presents a study on controlling the active and reactive power of a doubly fed induction generator (DFIG) for wind power generation using fuzzy logic. It first describes the DFIG system and its vector control scheme using rotor side and grid side converters. It then discusses modeling the DFIG, controlling the rotor side converter using stator flux orientation, controlling the grid side converter using voltage orientation, and designing a fuzzy logic controller. Simulation results show that a fuzzy logic controller combined with a PI controller improves the tracking of active and reactive power references under different operating conditions compared to using just a PI controller. The paper concludes that DFIG performance can be enhanced using a fuzzy tuned PI controller.
This document describes a direct torque control (DTC) scheme for an induction motor that uses a fuzzy logic controller (FLC) to reduce torque ripples. The DTC controls the motor torque and flux by selecting inverter voltage vectors. Typically this results in torque ripples. The FLC is designed to adaptively adjust the bandwidth of the torque hysteresis controller based on changes in motor torque and current over time. This helps minimize torque ripples and improve dynamic response. Simulation results using MATLAB/Simulink confirm that the FLC-based DTC scheme effectively controls the induction motor with reduced torque ripples compared to conventional DTC.
Study On Speed Control of DC MOTOR Using ThyristorIRJET Journal
This document discusses speed control of a DC motor using a thyristor. It first provides background on DC motors and thyristors. It then presents the mathematical model of a separately excited DC motor. Various methods for controlling DC motor speed are described, including armature voltage control, armature resistance control, and flux control. Single phase half wave, full wave, and dual converter drives are introduced as techniques for implementing thyristor-based speed control. A simulation model is presented to observe the effect of varying the firing angle of a single phase full converter on the torque-speed characteristic of the DC motor. The document concludes that thyristor-based drives can effectively control DC motor speed.
Direct torque control of IM using PID controller IJECEIAES
Direct torque control "DTC" technique is one of a high performance control system of an AC motor drive, which was proposed after the vector oriented control scheme during the resent 25 years. It has been developed rapidly for its concise system scheme, transient and dynamic performance. The DTC mechanism consists of voltage vector selection table, two hysteresis comparators and two estimator’s one for stator flux and another for electromagnetic torque. DTC is directly control torque and flux by using Voltage Source Inverter VSI, space vector and stator flux orientation and indirect speed regulated. A several control techniques can be used for improving the torque and flux performance. In this paper, the DTC with Proportional-Integral-Derivative (PID) controller used to improve the starting and dynamic performance of asynchronous motor AM, which gives good torque and flux response, best speed control and also minimize the unacceptable torque ripple. The mathematical model of DTC with PID controller of 3-phase induction motor IM are simulated under MatlabSimulink. Therefore, the DTC based on PID controller has good performance of IM compared to classical DTC for starting, running state and also during change in load.
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.
Close Loop Control of Induction Motor Using Z-Source InverterIJSRD
In this paper a new closed loop control of induction motor fed by a Z – source inverter based on the vector control or field oriented control strategy is presented. Induction motor is supplied by Z – source inverter, in the Z – source inverter the term Z denotes impedance which means a combination of L & C element which are cross connected. The Z-source inverter consists of a unique impedance network (or circuit) to couple the inverter main circuit to the power supply, hence providing great features that cannot be observed in the conventional voltage-source inverter and current-source inverters in which capacitor and inductor are used, respectively.In the field oriented control method or vector control method speed of the induction motor, torque & 3 phase stator current is given to the field oriented controller and gate pulses for the inverter is generated to obtain the desired operation of the induction motor.
Industrial Power Control by Integral Cycle Switching without Generating Harmo...IRJET Journal
This document discusses integral cycle switching control for industrial power control. It begins by introducing integral cycle control and its advantages over traditional phase control, such as introducing fewer harmonics into the power system. It then describes the principle of operation, including connecting the load to the power source for some number of cycles and then disconnecting it for off-cycles. The paper presents the simulation results showing waveforms and harmonic profiles that demonstrate reduced harmonics. It concludes that integral cycle control provides a low-cost and easy to operate method for AC power control with better efficiency and reduced losses compared to traditional phase control approaches.
Constant Frequency Torque Controller for DTC with Multilevel Inverter of Indu...IJPEDS-IAES
Direct Torque Control using multilevel inverter (DTC-MLI) with hysteresis
controller suffers from high torque and flux ripple and variable switching
frequency. In this paper, a constant frequency torque controller is proposed to
enhance the DTC-MLI performance. The operational concepts of the
constant switching frequency torque controller of a DTC-MLI system
followed by the simulation results and analysis are presented. The proposed
system significantly improves the DTC drive in terms of dynamic
performance, smaller torque and flux ripple, and retains a constant switching
frequency.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
Voltage recovery of induction generator using indirect torque control methodiaemedu
1) The document discusses using a STATCOM to indirectly control the torque of an induction generator connected to the grid through voltage modulation in order to improve voltage recovery following a fault.
2) It proposes an indirect torque control method where the STATCOM controls the generator's terminal voltage during recovery to limit torque and smooth transients.
3) Time-domain simulations show that indirect torque control with STATCOM successfully limits the peak torque and speeds recovery of the generator's voltage, speed, and torque following a three-phase fault.
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.
Comparison of Multi-Machine Transient Stability Limit Using UPFCIJMTST Journal
The stability of an interconnected power system is compare to normal or stable operation after having been
subjected to some form of disturbance. With interconnected systems continually growing in size and extending
over vast geographical regions, it is becoming increasingly more difficult to maintain synchronism between
various parts of the power system. This paper investigates the comparison of transient stabil ity limit of a
multi-machine power system wi th the help of a UPFC operated in perpendicular vol tage control
mo d e an d t h e i r i t ’ s c omp ar i s o n .
Speed Control System for BLDC Motor by using Direct Back EMF Detection Mathodijtsrd
BLDC motors are used in many industrial and traction applications due to high efficiency, low maintenance and high torque. For good performance of BLDC motors, the accurate knowledge of the rotor position is required. The need for the rotor position information in BLDC motors have been satisfied by use of some form of rotor position sensors. But to reduce cost, complexity and also to improve reliability of the system, sensor less drive system is preferred. In this paper, the development of sensor less control system for BLDC motor using a direct back EMF detection method is presented and simulation for proposed system is done with the help of MATLAB SIMULINK. Soe Sandar Aung | Thet Naing Htun "Speed Control System for BLDC Motor by using Direct Back EMF Detection Mathod" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd26624.pdfPaper URL: https://www.ijtsrd.com/engineering/electrical-engineering/26624/speed-control-system-for-bldc-motor-by-using-direct-back-emf-detection-mathod/soe-sandar-aung
Multi-machine system with Series FACTS device: Static synchronous series comp...IRJET Journal
This document presents a study of a multi-machine power system with and without a Static Synchronous Series Compensator (SSSC). The SSSC is modeled and its effect on the system is analyzed under different operating conditions. In normal load conditions, power flow increased by 8% with the SSSC. Under an 8% increased load, voltages were improved and disturbances decreased with the SSSC. During a fault, the SSSC helped settle the system faster and improved power flow recovery after the fault was cleared. The study demonstrates the benefits of the SSSC for improving power flow, damping oscillations, and enhancing transient stability.
Total Harmonic Distortion Analysis of a Four Switch 3-Phase Inverter Fed Spee...IJPEDS-IAES
This paper investigates the performance of a Model reference adaptive system (MRAS) based cost-effective drive system of an induction motor (IM) for low-cost applications - high performance industrial drive systems. In this paper, the MRAS is used as a speed estimator and the motor is fed from a four-switch three-phase (FSTP) inverter instead of a conventional six- switch three-phase (SSTP) inverter. This configuration reduces the cost of the inverter, the switching losses, and the complexity of the control algorithms and interface circuits, the proposed control approach reduces the computation for real-time implementation. The robustness of the proposed MRAS-based FSTP inverter fed IM drive is verified by Experimental results at different operating conditions using digital signal processor (DSP1103) for a 1.1 Kw motor. A performance comparison of the proposed FSTP inverter fed IM drive with a conventional SSTP inverter system is also made in terms of speed response and total harmonic distortion (THD) of the stator current. The proposed FSTP inverter fed IM drive is found quite acceptable considering its performance, cost reduction and other advantages features.
This article presents nonlinear control of wind conversion chain connected to the grid based on a permanent magnet synchronous generator. The control objectives are threefold; i) forcing the generator speed to track a varying reference signal in order to extract the maximum power at different wind speed (MPPT); ii) regulating the rectifier output capacitor voltage; iii) reducing the harmonic and reactive currents injected in the grid. This means that the inverter output current must be sinusoidal and in phase with the AC supply voltage (PFC). To this end, a nonlinear state-feedback control is developed, based on the average nonlinear model of the whole controlled system. This control strategy involves backstepping approach, Lyapunov stability and other tools from theory of linear systems. The proposed state-feedback control strategy is tested by numerical simulation which shows that the developed controller reaches its objectives.
Modeling and performance analysis of a small scale direct driven pmsg based w...Alexander Decker
This document summarizes a journal article that models and analyzes the performance of a small-scale direct-driven wind energy conversion system using a permanent magnet synchronous generator (PMSG) connected directly to the grid through a power electronic interface. It presents the modeling of the system components, including the wind turbine, PMSG, and power conditioning system consisting of a rectifier, boost chopper, and inverter. The power flow is analyzed for different wind velocities and the effect of duty ratio and modulation index on maximum power extraction is studied through MATLAB/SIMULINK simulations.
Direct Torque Control of Induction Motor Drive Fed from a Photovoltaic Multil...IJERA Editor
This paper presents Direct Torque Control (DTC) using Space Vector Modulation (SVM) for an induction motor drive fed from a photovoltaic multilevel inverter (PV-MLI). The system consists of two main parts PV DC power supply (PVDC) and MLI. The PVDC is used to generate DC isolated sources with certain ratios suitable for the adopted MLI. Beside the hardware system, the control system which uses the torque and speed estimation to control the load angle and to obtain the appropriate flux vector trajectory from which the voltage vector is directly derived based on direct torque control methods. The voltage vector is then generated by a hybrid multilevel inverter by employing space vector modulation (SVM). The inverter high quality output voltage which leads to a high quality IM performances. Besides, the MLI switching losses is very low due to most of the power cell switches are operating at nearly fundamental frequency. Some selected simulation results are presented for system validation.
This review paper is based on space vector based hysteresis current control in three phase PWM converter. In hysteresis current control technique, two, three or four level hysteresis comparator are used, which selects the appropriate inverter output voltage vectors by their switching phenomenon of vector based HCC, and it is used to control the current vector by keeping the current error vector in tolerance region. Through which the load gets desirable output current voltage. By keeping the zero phase difference between output current and voltage, acquires a high power factor by HCC voltage vector and this HCC voltage vector have some advantages over conventional HCC which are not to have interphase dependency and also maintaining constant modulation frequency or also reducing switching frequency. By this HCC, increase the system steady state performance and reducing dynamic response.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Master slave vector controlled double induction motor using unity power facto...eSAT Journals
Abstract
In the recent days most of the industries uses Induction motors as the primary loads. In order to meet the total load requirement
multiple motors are used. In this paper two Vector Controlled (VC) Induction Motors and a double closed loop PWM rectifier are
used to explain the operation of Master Slave Configuration. The work mainly concentrates on the operation of a Unity Power factor
Controlled (UPFC) PWM Rectifier as the input source for both the Vector Controlled Induction Motors. This UPFC PWM Rectifier
uses two closed loop pi control algorithms the inner loop controls the current and the outer loop controls the DC voltage. The
proposed model is simulated in Matlab/ Simulink and the results shows good synchronization for two induction motors operated in
master slave configuration.
Keywords: Vector Control, Induction Motor, PWM Rectifier, and Unity Power Factor Control
Analysis of wind turbine driven permanent magnet synchronous generator under ...Alexander Decker
This document analyzes the operation of a wind turbine driven permanent magnet synchronous generator (PMSG) under different loading conditions. It presents a model of a PMSG wind energy system in MATLAB/SIMULINK. The model includes a wind turbine model, drive train model, and PMSG model. Equations describing the behavior of each component are introduced. Simulation results show the PMSG can operate over a wide range of conditions with different load types and indicate the effect of different load types on operation. The PMSG is found to effectively operate in standalone mode when loaded with resistive, inductive, and nonlinear loads.
Two identical wound rotor induction machines are connected in a cascaded configuration to transfer power between two asynchronous grids. The stators of each machine are connected to different frequency grids, while the rotors are coupled mechanically and electrically. This allows the rotor fields to rotate at the same frequency, enabling power transfer. Mathematical equations are presented to model the steady-state power flow between the machines based on their electrical characteristics. Simulation results are shown for two identical machines demonstrating this approach can interconnect grids without restrictions on frequency differences.
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.
Carrier based hybrid pwm algorithm with reduced common mode voltageIAEME Publication
This document proposes a hybrid PWM algorithm to reduce common mode voltage variations in three-phase voltage source inverter fed induction motor drives. It presents a carrier-based approach to generate active zero state PWM techniques through addition of a zero sequence voltage. To further reduce harmonic distortion, a hybrid PWM technique is presented based on analysis of stator flux ripple. Simulation results on a v/f controlled induction motor drive show that the proposed algorithm minimizes common mode voltage variations compared to the space vector PWM algorithm.
PARAMETER IDENTIFICATION AND MODELLING OF SEPARATELY EXCITED DC MOTOR ijiert bestjournal
DC Motors can be used in various applications and c an be used in various sizes and rates as per the applications. In this paper we have focused on the physical parameters of DC motor. Modelling of any system is an important task in con trol applications because the electrical and mechanical components should be represented in math ematical form. Physical parameters are important in calculating the transfer function of D C motor. By using the physical parameters one can design the controller for controlling speed of the motor. A proportional�integral� derivative controller (PID controller) is a generic control loop feedback mechanism (controller) widely used in industrial control syst ems. The controller attempts to minimize the error by adjusting the process control inputs. The weighted sum of the proportionate,integrate,differentiate actions is used to adjust the process via a control element such as the position of a control valve,or the power supplied.
Basically, the direct torque control (DTC) drive system is operated at light load. At light load, supplying the drive system with rated flux will decrease the efficiency of the system. To maximize the efficiency of drive system, an optimal flux has been applied during steady-state but when a torque is suddenly needed, for example during acceleration, the dynamic of the torque response would be degraded. Therefore, a modification to the voltage vector as well as look-up table has been proposed for the torque response improvement. The proposed voltage vector is generated by adding two adjacent conventional voltage vectors and implemented by using duty ratio. The duty ratio is used to estimate the activation time of each conventional voltage vector in order to produce the proposed voltage vector.
Performance Analysis Of Induction Motor For Voltage Mode And Current Mode Con...IRJET Journal
This document discusses the performance analysis of an induction motor using voltage mode and current mode control. It compares hysteresis current control and space vector pulse width modulation (SVPWM). Hysteresis control directly limits current peaks but SVPWM provides higher voltage output and lower harmonic distortion. The document simulates an induction motor drive using SVPWM-based hysteresis current control in MATLAB. Key steps include Clark transformation to generate reference signals, switching between active and zero vectors to synthesize the reference signal, and using hysteresis control to generate PWM signals from current errors. Simulation results show the SVPWM controller provides good speed and current regulation for the induction motor.
Constant Frequency Torque Controller for DTC with Multilevel Inverter of Indu...IJPEDS-IAES
Direct Torque Control using multilevel inverter (DTC-MLI) with hysteresis
controller suffers from high torque and flux ripple and variable switching
frequency. In this paper, a constant frequency torque controller is proposed to
enhance the DTC-MLI performance. The operational concepts of the
constant switching frequency torque controller of a DTC-MLI system
followed by the simulation results and analysis are presented. The proposed
system significantly improves the DTC drive in terms of dynamic
performance, smaller torque and flux ripple, and retains a constant switching
frequency.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
Voltage recovery of induction generator using indirect torque control methodiaemedu
1) The document discusses using a STATCOM to indirectly control the torque of an induction generator connected to the grid through voltage modulation in order to improve voltage recovery following a fault.
2) It proposes an indirect torque control method where the STATCOM controls the generator's terminal voltage during recovery to limit torque and smooth transients.
3) Time-domain simulations show that indirect torque control with STATCOM successfully limits the peak torque and speeds recovery of the generator's voltage, speed, and torque following a three-phase fault.
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.
Comparison of Multi-Machine Transient Stability Limit Using UPFCIJMTST Journal
The stability of an interconnected power system is compare to normal or stable operation after having been
subjected to some form of disturbance. With interconnected systems continually growing in size and extending
over vast geographical regions, it is becoming increasingly more difficult to maintain synchronism between
various parts of the power system. This paper investigates the comparison of transient stabil ity limit of a
multi-machine power system wi th the help of a UPFC operated in perpendicular vol tage control
mo d e an d t h e i r i t ’ s c omp ar i s o n .
Speed Control System for BLDC Motor by using Direct Back EMF Detection Mathodijtsrd
BLDC motors are used in many industrial and traction applications due to high efficiency, low maintenance and high torque. For good performance of BLDC motors, the accurate knowledge of the rotor position is required. The need for the rotor position information in BLDC motors have been satisfied by use of some form of rotor position sensors. But to reduce cost, complexity and also to improve reliability of the system, sensor less drive system is preferred. In this paper, the development of sensor less control system for BLDC motor using a direct back EMF detection method is presented and simulation for proposed system is done with the help of MATLAB SIMULINK. Soe Sandar Aung | Thet Naing Htun "Speed Control System for BLDC Motor by using Direct Back EMF Detection Mathod" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd26624.pdfPaper URL: https://www.ijtsrd.com/engineering/electrical-engineering/26624/speed-control-system-for-bldc-motor-by-using-direct-back-emf-detection-mathod/soe-sandar-aung
Multi-machine system with Series FACTS device: Static synchronous series comp...IRJET Journal
This document presents a study of a multi-machine power system with and without a Static Synchronous Series Compensator (SSSC). The SSSC is modeled and its effect on the system is analyzed under different operating conditions. In normal load conditions, power flow increased by 8% with the SSSC. Under an 8% increased load, voltages were improved and disturbances decreased with the SSSC. During a fault, the SSSC helped settle the system faster and improved power flow recovery after the fault was cleared. The study demonstrates the benefits of the SSSC for improving power flow, damping oscillations, and enhancing transient stability.
Total Harmonic Distortion Analysis of a Four Switch 3-Phase Inverter Fed Spee...IJPEDS-IAES
This paper investigates the performance of a Model reference adaptive system (MRAS) based cost-effective drive system of an induction motor (IM) for low-cost applications - high performance industrial drive systems. In this paper, the MRAS is used as a speed estimator and the motor is fed from a four-switch three-phase (FSTP) inverter instead of a conventional six- switch three-phase (SSTP) inverter. This configuration reduces the cost of the inverter, the switching losses, and the complexity of the control algorithms and interface circuits, the proposed control approach reduces the computation for real-time implementation. The robustness of the proposed MRAS-based FSTP inverter fed IM drive is verified by Experimental results at different operating conditions using digital signal processor (DSP1103) for a 1.1 Kw motor. A performance comparison of the proposed FSTP inverter fed IM drive with a conventional SSTP inverter system is also made in terms of speed response and total harmonic distortion (THD) of the stator current. The proposed FSTP inverter fed IM drive is found quite acceptable considering its performance, cost reduction and other advantages features.
This article presents nonlinear control of wind conversion chain connected to the grid based on a permanent magnet synchronous generator. The control objectives are threefold; i) forcing the generator speed to track a varying reference signal in order to extract the maximum power at different wind speed (MPPT); ii) regulating the rectifier output capacitor voltage; iii) reducing the harmonic and reactive currents injected in the grid. This means that the inverter output current must be sinusoidal and in phase with the AC supply voltage (PFC). To this end, a nonlinear state-feedback control is developed, based on the average nonlinear model of the whole controlled system. This control strategy involves backstepping approach, Lyapunov stability and other tools from theory of linear systems. The proposed state-feedback control strategy is tested by numerical simulation which shows that the developed controller reaches its objectives.
Modeling and performance analysis of a small scale direct driven pmsg based w...Alexander Decker
This document summarizes a journal article that models and analyzes the performance of a small-scale direct-driven wind energy conversion system using a permanent magnet synchronous generator (PMSG) connected directly to the grid through a power electronic interface. It presents the modeling of the system components, including the wind turbine, PMSG, and power conditioning system consisting of a rectifier, boost chopper, and inverter. The power flow is analyzed for different wind velocities and the effect of duty ratio and modulation index on maximum power extraction is studied through MATLAB/SIMULINK simulations.
Direct Torque Control of Induction Motor Drive Fed from a Photovoltaic Multil...IJERA Editor
This paper presents Direct Torque Control (DTC) using Space Vector Modulation (SVM) for an induction motor drive fed from a photovoltaic multilevel inverter (PV-MLI). The system consists of two main parts PV DC power supply (PVDC) and MLI. The PVDC is used to generate DC isolated sources with certain ratios suitable for the adopted MLI. Beside the hardware system, the control system which uses the torque and speed estimation to control the load angle and to obtain the appropriate flux vector trajectory from which the voltage vector is directly derived based on direct torque control methods. The voltage vector is then generated by a hybrid multilevel inverter by employing space vector modulation (SVM). The inverter high quality output voltage which leads to a high quality IM performances. Besides, the MLI switching losses is very low due to most of the power cell switches are operating at nearly fundamental frequency. Some selected simulation results are presented for system validation.
This review paper is based on space vector based hysteresis current control in three phase PWM converter. In hysteresis current control technique, two, three or four level hysteresis comparator are used, which selects the appropriate inverter output voltage vectors by their switching phenomenon of vector based HCC, and it is used to control the current vector by keeping the current error vector in tolerance region. Through which the load gets desirable output current voltage. By keeping the zero phase difference between output current and voltage, acquires a high power factor by HCC voltage vector and this HCC voltage vector have some advantages over conventional HCC which are not to have interphase dependency and also maintaining constant modulation frequency or also reducing switching frequency. By this HCC, increase the system steady state performance and reducing dynamic response.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Master slave vector controlled double induction motor using unity power facto...eSAT Journals
Abstract
In the recent days most of the industries uses Induction motors as the primary loads. In order to meet the total load requirement
multiple motors are used. In this paper two Vector Controlled (VC) Induction Motors and a double closed loop PWM rectifier are
used to explain the operation of Master Slave Configuration. The work mainly concentrates on the operation of a Unity Power factor
Controlled (UPFC) PWM Rectifier as the input source for both the Vector Controlled Induction Motors. This UPFC PWM Rectifier
uses two closed loop pi control algorithms the inner loop controls the current and the outer loop controls the DC voltage. The
proposed model is simulated in Matlab/ Simulink and the results shows good synchronization for two induction motors operated in
master slave configuration.
Keywords: Vector Control, Induction Motor, PWM Rectifier, and Unity Power Factor Control
Analysis of wind turbine driven permanent magnet synchronous generator under ...Alexander Decker
This document analyzes the operation of a wind turbine driven permanent magnet synchronous generator (PMSG) under different loading conditions. It presents a model of a PMSG wind energy system in MATLAB/SIMULINK. The model includes a wind turbine model, drive train model, and PMSG model. Equations describing the behavior of each component are introduced. Simulation results show the PMSG can operate over a wide range of conditions with different load types and indicate the effect of different load types on operation. The PMSG is found to effectively operate in standalone mode when loaded with resistive, inductive, and nonlinear loads.
Two identical wound rotor induction machines are connected in a cascaded configuration to transfer power between two asynchronous grids. The stators of each machine are connected to different frequency grids, while the rotors are coupled mechanically and electrically. This allows the rotor fields to rotate at the same frequency, enabling power transfer. Mathematical equations are presented to model the steady-state power flow between the machines based on their electrical characteristics. Simulation results are shown for two identical machines demonstrating this approach can interconnect grids without restrictions on frequency differences.
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.
Carrier based hybrid pwm algorithm with reduced common mode voltageIAEME Publication
This document proposes a hybrid PWM algorithm to reduce common mode voltage variations in three-phase voltage source inverter fed induction motor drives. It presents a carrier-based approach to generate active zero state PWM techniques through addition of a zero sequence voltage. To further reduce harmonic distortion, a hybrid PWM technique is presented based on analysis of stator flux ripple. Simulation results on a v/f controlled induction motor drive show that the proposed algorithm minimizes common mode voltage variations compared to the space vector PWM algorithm.
PARAMETER IDENTIFICATION AND MODELLING OF SEPARATELY EXCITED DC MOTOR ijiert bestjournal
DC Motors can be used in various applications and c an be used in various sizes and rates as per the applications. In this paper we have focused on the physical parameters of DC motor. Modelling of any system is an important task in con trol applications because the electrical and mechanical components should be represented in math ematical form. Physical parameters are important in calculating the transfer function of D C motor. By using the physical parameters one can design the controller for controlling speed of the motor. A proportional�integral� derivative controller (PID controller) is a generic control loop feedback mechanism (controller) widely used in industrial control syst ems. The controller attempts to minimize the error by adjusting the process control inputs. The weighted sum of the proportionate,integrate,differentiate actions is used to adjust the process via a control element such as the position of a control valve,or the power supplied.
Basically, the direct torque control (DTC) drive system is operated at light load. At light load, supplying the drive system with rated flux will decrease the efficiency of the system. To maximize the efficiency of drive system, an optimal flux has been applied during steady-state but when a torque is suddenly needed, for example during acceleration, the dynamic of the torque response would be degraded. Therefore, a modification to the voltage vector as well as look-up table has been proposed for the torque response improvement. The proposed voltage vector is generated by adding two adjacent conventional voltage vectors and implemented by using duty ratio. The duty ratio is used to estimate the activation time of each conventional voltage vector in order to produce the proposed voltage vector.
Performance Analysis Of Induction Motor For Voltage Mode And Current Mode Con...IRJET Journal
This document discusses the performance analysis of an induction motor using voltage mode and current mode control. It compares hysteresis current control and space vector pulse width modulation (SVPWM). Hysteresis control directly limits current peaks but SVPWM provides higher voltage output and lower harmonic distortion. The document simulates an induction motor drive using SVPWM-based hysteresis current control in MATLAB. Key steps include Clark transformation to generate reference signals, switching between active and zero vectors to synthesize the reference signal, and using hysteresis control to generate PWM signals from current errors. Simulation results show the SVPWM controller provides good speed and current regulation for the induction motor.
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.
Enhanced Torque Control and Reduced Switching Frequency in Direct Torque Cont...IJPEDS-IAES
Direct Torque Control (DTC) of induction machine has received wide
acceptance in many adjustable speed drive applications due to its simplicity
and high performance torque control. However, the DTC using a common
two-level inverter poses two major problems such as higher switching
frequency (or power loss) and larger torque ripple. These problems are due to
inappropriate voltage vectors which are selected among a limited number of
voltage vectors available in two-level inverter. The proposed research aims to
formulate an optimal switching strategy using Dual-Inverter Supplied Drive
for high performances of DTC. By using dual-inverter supplied, it provides
greater number of voltage vectors which can offer more options to select the
most appropriate voltage vectors. The most appropriate voltage vectors
should able to produce minimum torque slope but sufficient to satisfy torque
demands. The identification is accomplished by using an equation of rate of
change of torque which is derived from the induction machine equations. The
proposed strategy also introduces a block of modification of torque error
status which is responsible to modify the status such that it can determine the
most optimal voltage vectors from a look-up table, according to motor
operating conditions. The improvements obtained are as follows; 1)
minimization of switching frequency (reduce power loss), and 2) reduction of
torque ripple. Some improvements obtained in the proposed strategy were
verified via experimentations.
Direct Torque Control (DTC) is widely applied for ac motor drives as it offers high performance torque control with a simple control strategy. However, conventional DTC poses some disadvantages especially in term of variable switching frequency and large torque ripple due to the utilization of torque hysteresis controller. Other than that, performance of conventional DTC fed by two-level inverter is also restricted by the limited numbers of voltage vectors which lead to inappropriate selection of voltage vectors for different speed operations. This research aims to propose a Constant Switching Frequency (CSF) torque controller for DTC of induction motor (IM) fed by three-level Neutral-Point Clamped (NPC) inverter. The proposed torque controller utilizes PI controller which apply different gain for different speed operation. Besides, the utilization of NPC inverter provides greater number of voltage vectors which allow appropriate selection of voltage vectors for different operating condition. Using the proposed method, the improvement of DTC drives in term of producing a constant switching operation and minimizing torque ripple are achieved and validated via experimental results.
Alternating current (AC) electrical drives mainly require smaller current (or torque) ripples and lower total harmonic distortion (THD) of voltage for excellent drive performances. Normally, in practice, to achieve these requirements, the inverter needs to be operated at high switching frequency. By operating at high switching frequency, the size of filter can be reduced. However, the inverter which oftenly employs insulated gate bipolar transistor (IGBT) for high power applications cannot be operated at high switching frequency. This is because, the IGBT switching frequency cannot be operated above 50 kHz due to its thermal restrictions. This paper proposes an alternate switching strategy to enable the use of IGBT for operating the inverter at high switching frequency to improve THD performances. In this strategy, each IGBT in a group of switches in the modified inverter circuit will operate the switching frequency at one-fourth of the inverter switching frequency. The alternate switching is implemented using simple analog and digital integrated circuits.
A single rating inductor multilevel current source inverter with pwm strategieIAEME Publication
This document summarizes a research paper about a single-rating inductor multilevel current source inverter (MCSI) topology that uses phase-shifted carrier pulse width modulation (PSC-SPWM) and space vector modulation (SVM) control strategies. The proposed MCSI consists of identical modules where each module uses two balance inductors and six switches to determine different current levels at the output. PSC-SPWM is implemented using a state machine approach to balance the current in the inductors while minimizing switching frequency. Simulation results show the performance of a seven-level, three-module arrangement of the proposed MCSI topology.
A Novel Direct Torque Control for Induction Machine Drive System with Low Tor...IAES-IJPEDS
This document describes a novel direct torque control method for induction machine drives using space vector modulation (DTC-SVM) to reduce torque and flux ripples. Simulation results show the proposed DTC-SVM control achieves lower ripples compared to the conventional DTC method. The DTC-SVM control strategy is designed and simulated using Matlab/Simulink and implemented on an FPGA using Xilinx System Generator. Simulation results verify the DTC-SVM control is effective at minimizing torque and flux ripples for induction machine drives.
This document summarizes a research paper on sensorless direct torque control of interior permanent magnet synchronous motors for embedded systems using an MRAS observer. It begins with an introduction to embedded systems and IPMSMs. It then provides the mathematical model of an IPMSM and describes the principles of direct torque control, including flux and torque hysteresis controllers and the inverter switching table. It presents an MRAS observer as a sensorless closed-loop algorithm for estimating rotor speed and position. In the simulation results, the proposed sensorless DTC control method using an MRAS observer is effective for embedded system applications.
In this article, we are interested in the improvement of the performances of Doubly Fed Induction Machine (DFIM) operating in motor mode by the use of the direct torque control (DTC). Firstly, we focused on the modeling of the DFIM and the study of the principle of functioning of the DTC control. Then, we implement this control on the Matlab/Simulink environment. Secondly, we present the simulation results of the proposed control. The analysis of these results shows clearly that the system based on the DFIM studied follows perfectly the set points, what allowed us to justify the efficiency of the elaborate control.
Modulation Index Variation Effect on Harmonic Behavior of Fifteen Multilevel ...IJECEIAES
The Market for photovoltaic cells (PV) has grown fast due to a higher demand on PV applications. However, there are still the transport and connection problems of the PV systems to the grid because of the difference in the current form. To assure the adequate connection between the PV sources and the network, the conversion of direct current (DC) to an alternative current (AC) is required and provided by an electronic device known as the inverter. In this last years, the conventional inverter structure reached its limits in power level and conversion performance. The multilevel inverter (MLI) structure was introduced and widely used in high power and high voltage applications to solve the conventional inverter limitation problem. In this paper, the Neutral-Point-Clamped (NPC) topology of the MLI was simulated to evaluate the effect of modulation index variation of the control technique on the harmonic behavior of the fifteen-level NPC. The simulation results were useful for the optimization of the MLI control technique toward the decrease of the harmonic (THD) effect on the NPC MLI.
Small Signal Modeling Of Controller For Statcom Used In Distribution System F...IJERA Editor
This document presents a small signal model of a STATCOM (Static Synchronous Compensator) used for reactive power management in a distribution system. A PI controller is designed for the reactive current component of the STATCOM. The model linearizes the nonlinear STATCOM model and performs small signal modeling of the phase angle and modulation index. Simulation results in MATLAB/Simulink show the model with PI controllers can improve the power factor of the grid current for linear inductive loads by adjusting the reactive power output of the STATCOM.
This paper focuses on the modeling and control of a wind energy conversion chain using a permanent magnet synchronous machine. This system behaves a turbine, a generator, DC/DC and DC/AC power converters. These are connected on both sides to the DC bus, where the inverter is followed by a filter which is connected to the grid. In this paper, we have been used two types of controllers. For the stator side converter, we consider the Takagi-Sugeno approach where the parameters of controller have been computed by the theory of linear matrix inequalities. The stability synthesis has been checked using the Lyapunov theory. According to the grid side converter, the proportional integral controller is exploited to keep a constant voltage on the DC bus and control both types of powers. The simulation results demonstrate the robustness of the approach used.
Three inverters are operated in parallel using P-V/Q-F droop control to share load proportionally in a microgrid. The droop control principle ties the inverter output active power to voltage frequency and reactive power to voltage amplitude, allowing proportional load sharing without communication between inverters. A mathematical model of a three-phase inverter with LC filter is derived based on voltage and current dual control loops. Simulation results in Matlab/Simulink indicate the droop control scheme effectively balances voltage magnitude and frequency for proportional power sharing between parallel inverters.
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.
Simulation of 3-phase matrix converter using space vector modulationIJECEIAES
This paper illustrates the simulation of 3-phase matrix converter using Space Vector Modulation (SVM). Variable AC output voltage engendered using matrix converter with bidirectional power switches controlled by appropriate switching pulse. The conventional PWM converter engenders switching common mode voltage across the load system terminals, which cause to common mode current and its leads to bearing failure in load drive. These problems can be rectified using SVM and which minimize the effect on the harmonic fluctuation in AC output voltage and stress on the power switch is reduced using bidirectional switch for proposed 3-phase matrix converter. The simulation results have been presented to validate the proposed system using matlab / simulink.
Parameter estimation of three-phase linear induction motor by a DSP-based el...IJECEIAES
This work describes a method to characterize a three-phase linear induction motor in order to determine the various parameters used in its per-phase equivalent circuit by a DSP-based electric-drives system. In LIM (Linear Induction Motor), the air gap is very large compared with the RIMs (Rotary Induction Motors). Further, the secondary part normally does not have slotted structure. It is just made of aluminum and steel plates. Therefore, the effective air gap is larger than the physical air gap. High air gap makes a larger leakage inductance. It leads to lower efficiency and lower power factor. DC resistance test will be done to determine the value of Rs. The primary Inductance Ls will be calculated by running the LIM at synchronous speed. The secondary parameters i.e. Llr and Rr′ will be calculated by blocked-mover test. The experiment for no load test is shown and include a DC motor coupled to the LIM under test. Two methods to calculate the secondary parameters are described.
This paper proposes a novel integrated AC/DC/AC converter for direct drive permanent magnet wind power generation systems. The converter aims to reduce switching losses and minimize circulating currents in the power converters used in wind power systems. It uses a three-switch Vienna rectifier for rectification to reduce switching losses and improve power factor. For inversion, it uses a nine-switch Ultra Sparse Matrix Converter (USMC) to minimize circulating currents. Experimental results show the converter achieves high performance by minimizing losses and improving the overall system.
This document proposes a novel integrated AC/DC/AC converter for direct drive permanent magnet wind power generation systems. The converter aims to reduce switching losses and minimize circulating currents present in typical power converters. It uses a three-switch Vienna rectifier for rectification to reduce switching losses and improve power factor. For inversion, it uses a nine-switch Ultra Sparse Matrix Converter (USMC) to minimize circulating currents. Experimental results show the proposed converter achieves high performance by reducing losses and improving efficiency compared to conventional converters.
This paper proposes a novel integrated AC/DC/AC converter for direct drive permanent magnet wind power generation systems. The converter aims to reduce switching losses and minimize circulating currents in the power converters used in wind power systems. It uses a three-switch Vienna rectifier for rectification to reduce switching losses and improve power factor. For inversion, it uses a nine-switch Ultra Sparse Matrix Converter (USMC) to minimize circulating currents. Experimental results show the converter achieves high performance by minimizing losses and improving the overall system.
Similar to Direct Torque Control of Two Induction Motors Using the Nine-Switch Inverter (20)
The aim of this research is the speed tracking of the permanent magnet synchronous motor (PMSM) using an intelligent Neural-Network based adapative backstepping control. First, the model of PMSM in the Park synchronous frame is derived. Then, the PMSM speed regulation is investigated using the classical method utilizing the field oriented control theory. Thereafter, a robust nonlinear controller employing an adaptive backstepping strategy is investigated in order to achieve a good performance tracking objective under motor parameters changing and external load torque application. In the final step, a neural network estimator is integrated with the adaptive controller to estimate the motor parameters values and the load disturbance value for enhancing the effectiveness of the adaptive backstepping controller. The robsutness of the presented control algorithm is demonstrated using simulation tests. The obtained results clearly demonstrate that the presented NN-adaptive control algorithm can provide good trackingperformances for the speed trackingin the presence of motor parameter variation and load application.
The document presents a new method for fault classification and direction discrimination in transmission lines using 1D convolutional neural networks (1D-CNNs). A 132kV transmission line model is simulated to generate training and testing data for the 1D-CNN algorithm. The proposed 1D-CNN approach directly uses the voltage and current signals from one end as input, merging feature extraction and classification into a single learning process. Testing shows the 1D-CNN method accurately classifies and discriminates fault direction with higher accuracy than conventional neural network and fuzzy neural network methods under different fault conditions.
Among the most widespread renewable energy sources is solar energy; Solar panels offer a green, clean, and environmentally friendly source of energy. In the presence of several advantages of the use of photovoltaic systems, the random operation of the photovoltaic generator presents a great challenge, in the presence of a critical load. Among the most used solutions to overcome this problem is the combination of solar panels with generators or with the public grid or both. In this paper, an energy management strategy is proposed with a safety aspect by using artificial neural networks (ANNs), in order to ensure a continuous supply of electricity to consumers with a maximum solicitation of renewable energy.
In this paper, the artificial neural network (ANN) has been utilized for rotating machinery faults detection and classification. First, experiments were performed to measure the lateral vibration signals of laboratory test rigs for rotor-disk-blade when the blades are defective. A rotor-disk-blade system with 6 regular blades and 5 blades with various defects was constructed. Second, the ANN was applied to classify the different x- and y-axis lateral vibrations due to different blade faults. The results based on training and testing with different data samples of the fault types indicate that the ANN is robust and can effectively identify and distinguish different blade faults caused by lateral vibrations in a rotor. As compared to the literature, the present paper presents a novel work of identifying and classifying various rotating blade faults commonly encountered in rotating machines using ANN. Experimental data of lateral vibrations of the rotor-disk-blade system in both x- and y-directions are used for the training and testing of the network.
This paper focuses on the artificial bee colony (ABC) algorithm, which is a nonlinear optimization problem. is proposed to find the optimal power flow (OPF). To solve this problem, we will apply the ABC algorithm to a power system incorporating wind power. The proposed approach is applied on a standard IEEE-30 system with wind farms located on different buses and with different penetration levels to show the impact of wind farms on the system in order to obtain the optimal settings of control variables of the OPF problem. Based on technical results obtained, the ABC algorithm is shown to achieve a lower cost and losses than the other methods applied, while incorporating wind power into the system, high performance would be gained.
The significance of the solar energy is to intensify the effectiveness of the Solar Panel with the use of a primordial solar tracking system. Here we propounded a solar positioning system with the use of the global positioning system (GPS) , artificial neural network (ANN) and image processing (IP) . The azimuth angle of the sun is evaluated using GPS which provide latitude, date, longitude and time. The image processing used to find sun image through which centroid of sun is calculated and finally by comparing the centroid of sun with GPS quadrate to achieve optimum tracking point. Weather conditions and situation observed through AI decision making with the help of IP algorithms. The presented advance adaptation is analyzed and established via experimental effects which might be made available on the memory of the cloud carrier for systematization. The proposed system improve power gain by 59.21% and 10.32% compare to stable system (SS) and two-axis solar following system (TASF) respectively. The reduced tracking error of IoT based Two-axis solar following system (IoT-TASF) reduces their azimuth angle error by 0.20 degree.
Kosovo has limited renewable energy resources and its power generation sector is based on fossil fuels. Such a situation emphasizes the importance of active research and efficient use of renewable energy potential. According to the analysis of meteorological data for Kosovo, it can be concluded that among the most attractive potential wind power sites are the locations known as Kitka (42° 29' 41" N and 21° 36' 45" E) and Koznica (42° 39′ 32″ N, 21° 22′30″E). The two terrains in which the analysis was carried out are mountain areas, with altitudes of 1142 m (Kitka) and 1230 m (Koznica). the same measuring height, about 84 m above the ground, is obtained for these average wind speeds: Kitka 6,667 m/s and Koznica 6,16 m/s. Since the difference in wind speed is quite large versus a difference in altitude that is not being very large, analyses are made regarding the terrain characteristics including the terrain relief features. In this paper it will be studied how much the roughness of the terrain influences the output energy. Also, that the assumption to be taken the same as to how much they will affect the annual energy produced.
The document summarizes a research paper that proposes using a battery energy storage system (BESS) with droop control to reduce frequency fluctuations in a multi-machine power system connected to a large-scale photovoltaic (PV) plant. The paper develops a droop control strategy for the BESS that incorporates a frequency error signal and dead-band. Simulation results using PSCAD/EMTDC software show that the proposed droop control-based BESS can efficiently curtail frequency oscillations caused by fluctuations in PV power injection due to changing solar irradiance.
This study investigates experimentally the performance of two-dimensional solar tracking systems with reflector using commercial silicon based photovoltaic module, with open and closed loop control systems. Different reflector materials were also investigated. The experiments were performed at the Hashemite University campus in Zarqa at a latitude of 32⁰, in February and March. Photovoltaic output power and performance were analyzed. It was found that the modified photovoltaic module with mirror reflector generated the highest value of power, while the temperature reached a maximum value of 53 ̊ C. The modified module suggested in this study produced 5% more PV power than the two-dimensional solar tracking systems without reflector and produced 12.5% more PV power than the fixed PV module with 26⁰ tilt angle.
The development of modeling wind speed plays a very important in helping to obtain the actual wind speed data for the benefit of the power plant planning in the future. The wind speed in this paper is obtained from a PCE-FWS 20 type measuring instrument with a duration of 30 minutes which is accumulated into monthly data for one year (2019). Despite the many wind speed modeling that has been done by researchers. Modeling wind speeds proposed in this study were obtained from the modified Rayleigh distribution. In this study, the Rayleigh scale factor (Cr) and modified Rayleigh scale factor (Cm) were calculated. The observed wind speed is compared with the predicted wind characteristics. The data fit test used correlation coefficient (R2), root means square error (RMSE), and mean absolute percentage error (MAPE). The results of the proposed modified Rayleigh model provide very good results for users.
This paper deals with an advanced design for a pump powered by solar energyto supply agricultural lands with water and also the maximum power point is used to extract the maximum value of the energy available inside the solar panels and comparing between techniques MPPT such as Incremental conductance, perturb & observe, fractional short current circuit, and fractional open voltage circuit to find the best technique among these. The solar system is designed with main parts: photovoltaic (PV) panel, direct current/direct current (DC/DC) converter, inverter, filter, and in addition, the battery is used to save energy in the event that there is an increased demand for energy and not to provide solar radiation, as well as saving energy in the case of generation more than demand. This work was done using the matrix laboratory (MATLAB) simulink program.
The objective of this paper is to provide an overview of the current state of renewable energy resources in Bangladesh, as well as to examine various forms of renewable energies in order to gain a comprehensive understanding of how to address Bangladesh's power crisis issues in a sustainable manner. Electricity is currently the most useful kind of energy in Bangladesh. It has a substantial influence on a country's socioeconomic standing and living standards. Maintaining a stable source of energy at a cost that is affordable to everyone has been a constant battle for decades. Bangladesh is blessed with a wealth of natural resources. Bangladesh has a huge opportunity to accelerate its economic development while increasing energy access, livelihoods, and health for millions of people in a sustainable way due to the renewable energy system.
When the irradiance distribution over the photovoltaic panels is uniform, the pursuit of the maximum power point is not reached, which has allowed several researchers to use traditional MPPT techniques to solve this problem Among these techniques a PSO algorithm is used to have the maximum global power point (GMPPT) under partial shading. On the other hand, this one is not reliable vis-à-vis the pursuit of the MPPT. Therefore, in this paper we have treated another technique based on a new modified PSO algorithm so that the power can reach its maximum point. The PSO algorithm is based on the heuristic method which guarantees not only the obtaining of MPPT but also the simplicity of control and less expensive of the system. The results are obtained using MATLAB show that the proposed modified PSO algorithm performs better than conventional PSO and is robust to different partial shading models.
A stable operation of wind turbines connected to the grid is an essential requirement to ensure the reliability and stability of the power system. To achieve such operational objective, installing static synchronous compensator static synchronous compensator (STATCOM) as a main compensation device guarantees the voltage stability enhancement of the wind farm connected to distribution network at different operating scenarios. STATCOM either supplies or absorbs reactive power in order to ensure the voltage profile within the standard-margins and to avoid turbine tripping, accordingly. This paper present new study that investigates the most suitable-location to install STATCOM in a distribution system connected wind farm to maintain the voltage-levels within the stability margins. For a large-scale squirrel cage induction generator squirrel-cage induction generator (SCIG-based) wind turbine system, the impact of STATCOM installation was tested in different places and voltage-levels in the distribution system. The proposed method effectiveness in enhancing the voltage profile and balancing the reactive power is validated, the results were repeated for different scenarios of expected contingencies. The voltage profile, power flow, and reactive power balance of the distribution system are observed using MATLAB/Simulink software.
The electrical and environmental parameters of polymer solar cells (PSC) provide important information on their performance. In the present article we study the influence of temperature on the voltage-current (I-V) characteristic at different temperatures from 10 °C to 90 °C, and important parameters like bandgap energy Eg, and the energy conversion efficiency η. The one-diode electrical model, normally used for semiconductor cells, has been tested and validated for the polemeral junction. The PSC used in our study are formed by the poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM). Our technique is based on the combination of two steps; the first use the Least Mean Squares (LMS) method while the second use the Newton-Raphson algorithm. The found results are compared to other recently published works, they show that the developed approach is very accurate. This precision is proved by the minimal values of statistical errors (RMSE) and the good agreement between both the experimental data and the I-V simulated curves. The obtained results show a clear and a monotonic dependence of the cell efficiency on the studied parameters.
The inverter is the principal part of the photovoltaic (PV) systems that assures the direct current/alternating current (DC/AC) conversion (PV array is connected directly to an inverter that converts the DC energy produced by the PV array into AC energy that is directly connected to the electric utility). In this paper, we present a simple method for detecting faults that occurred during the operation of the inverter. These types of faults or faults affect the efficiency and cost-effectiveness of the photovoltaic system, especially the inverter, which is the main component responsible for the conversion. Hence, we have shown first the faults obtained in the case of the short circuit. Second, the open circuit failure is studied. The results demonstrate the efficacy of the proposed method. Good monitoring and detection of faults in the inverter can increase the system's reliability and decrease the undesirable faults that appeared in the PV system. The system behavior is tested under variable parameters and conditions using MATLAB/Simulink.
The document describes a proposed modified bridge-type nonsuperconducting fault current limiter (NSFCL) for distribution networks. The NSFCL consists of a bridge rectifier, two DC reactors (one small in series and one large in parallel), and an IGBT semiconductor switch controlled by a command circuit. During normal operation, the IGBT is on and the parallel reactor is bypassed, making the NSFCL invisible. During a fault, the IGBT turns off, inserting the parallel reactor to limit fault current. Simulation results showed the design effectively limits fault current while minimally affecting normal operation.
This paper provides a new approach to reducing high-order harmonics in 400 Hz inverter using a three-level neutral-point clamped (NPC) converter. A voltage control loop using the harmonic compensation combined with NPC clamping diode control technology. The capacitor voltage imbalance also causes harmonics in the output voltage. For 400 Hz inverter, maintain a balanced voltage between the two input (direct current) (DC) capacitors is difficult because the pulse width modulation (PWM) modulation frequency ratio is low compared to the frequency of the output voltage. A method of determining the current flowing into the capacitor to control the voltage on the two balanced capacitors to ensure fast response reversal is also given in this paper. The combination of a high-harmonic resonator controller and a neutral-point voltage controller working together on the 400 Hz NPC inverter structure is given in this paper.
Direct current (DC) electronic load is a useful equipment for testing the electrical system. It can emulate various load at a high rating. The electronic load requires a power converter to operate and a linear regulator is a common option. Nonetheless, it is hard to control due to the temperature variation. This paper proposed a DC electronic load using the boost converter. The proposed electronic load operates in the continuous current mode and control using the integral controller. The electronic load using the boost converter is compared with the electronic load using the linear regulator. The results show that the boost converter able to operate as an electronic load with an error lower than 0.5% and response time lower than 13 ms.
This paper presents a new simplified cascade multiphase DC-DC buck power converter suitable for low voltage and large current applications. Cascade connection enables very low voltage ratio without using very small duty cycles nor transformers. Large current with very low ripple content is achieved by using the multiphase technique. The proposed converter needs smaller number of components compared to conventional cascade multiphase DC-DC buck power converters. This paper also presents useful analysis of the proposed DC-DC buck power converter with a method to optimize the phase and cascade number. Simulation and experimental results are included to verify the basic performance of the proposed DC-DC buck power converter.
More from International Journal of Power Electronics and Drive Systems (20)
Null Bangalore | Pentesters Approach to AWS IAMDivyanshu
#Abstract:
- Learn more about the real-world methods for auditing AWS IAM (Identity and Access Management) as a pentester. So let us proceed with a brief discussion of IAM as well as some typical misconfigurations and their potential exploits in order to reinforce the understanding of IAM security best practices.
- Gain actionable insights into AWS IAM policies and roles, using hands on approach.
#Prerequisites:
- Basic understanding of AWS services and architecture
- Familiarity with cloud security concepts
- Experience using the AWS Management Console or AWS CLI.
- For hands on lab create account on [killercoda.com](https://killercoda.com/cloudsecurity-scenario/)
# Scenario Covered:
- Basics of IAM in AWS
- Implementing IAM Policies with Least Privilege to Manage S3 Bucket
- Objective: Create an S3 bucket with least privilege IAM policy and validate access.
- Steps:
- Create S3 bucket.
- Attach least privilege policy to IAM user.
- Validate access.
- Exploiting IAM PassRole Misconfiguration
-Allows a user to pass a specific IAM role to an AWS service (ec2), typically used for service access delegation. Then exploit PassRole Misconfiguration granting unauthorized access to sensitive resources.
- Objective: Demonstrate how a PassRole misconfiguration can grant unauthorized access.
- Steps:
- Allow user to pass IAM role to EC2.
- Exploit misconfiguration for unauthorized access.
- Access sensitive resources.
- Exploiting IAM AssumeRole Misconfiguration with Overly Permissive Role
- An overly permissive IAM role configuration can lead to privilege escalation by creating a role with administrative privileges and allow a user to assume this role.
- Objective: Show how overly permissive IAM roles can lead to privilege escalation.
- Steps:
- Create role with administrative privileges.
- Allow user to assume the role.
- Perform administrative actions.
- Differentiation between PassRole vs AssumeRole
Try at [killercoda.com](https://killercoda.com/cloudsecurity-scenario/)
Digital Twins Computer Networking Paper Presentation.pptxaryanpankaj78
A Digital Twin in computer networking is a virtual representation of a physical network, used to simulate, analyze, and optimize network performance and reliability. It leverages real-time data to enhance network management, predict issues, and improve decision-making processes.
Gas agency management system project report.pdfKamal Acharya
The project entitled "Gas Agency" is done to make the manual process easier by making it a computerized system for billing and maintaining stock. The Gas Agencies get the order request through phone calls or by personal from their customers and deliver the gas cylinders to their address based on their demand and previous delivery date. This process is made computerized and the customer's name, address and stock details are stored in a database. Based on this the billing for a customer is made simple and easier, since a customer order for gas can be accepted only after completing a certain period from the previous delivery. This can be calculated and billed easily through this. There are two types of delivery like domestic purpose use delivery and commercial purpose use delivery. The bill rate and capacity differs for both. This can be easily maintained and charged accordingly.
Discover the latest insights on Data Driven Maintenance with our comprehensive webinar presentation. Learn about traditional maintenance challenges, the right approach to utilizing data, and the benefits of adopting a Data Driven Maintenance strategy. Explore real-world examples, industry best practices, and innovative solutions like FMECA and the D3M model. This presentation, led by expert Jules Oudmans, is essential for asset owners looking to optimize their maintenance processes and leverage digital technologies for improved efficiency and performance. Download now to stay ahead in the evolving maintenance landscape.
Applications of artificial Intelligence in Mechanical Engineering.pdfAtif Razi
Historically, mechanical engineering has relied heavily on human expertise and empirical methods to solve complex problems. With the introduction of computer-aided design (CAD) and finite element analysis (FEA), the field took its first steps towards digitization. These tools allowed engineers to simulate and analyze mechanical systems with greater accuracy and efficiency. However, the sheer volume of data generated by modern engineering systems and the increasing complexity of these systems have necessitated more advanced analytical tools, paving the way for AI.
AI offers the capability to process vast amounts of data, identify patterns, and make predictions with a level of speed and accuracy unattainable by traditional methods. This has profound implications for mechanical engineering, enabling more efficient design processes, predictive maintenance strategies, and optimized manufacturing operations. AI-driven tools can learn from historical data, adapt to new information, and continuously improve their performance, making them invaluable in tackling the multifaceted challenges of modern mechanical engineering.
Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELijaia
As digital technology becomes more deeply embedded in power systems, protecting the communication
networks of Smart Grids (SG) has emerged as a critical concern. Distributed Network Protocol 3 (DNP3)
represents a multi-tiered application layer protocol extensively utilized in Supervisory Control and Data
Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
dataset (DNP3), which focuses on unauthorized commands and Denial of Service (DoS) cyberattacks, to
train and test our model. The results of our experiments show that our CNN-LSTM method is much better
at finding smart grid intrusions than other deep learning algorithms used for classification. In addition,
our proposed approach improves accuracy, precision, recall, and F1 score, achieving a high detection
accuracy rate of 99.50%.
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each motor are calculated and the influence of the NSI space vectors on each motor’s torque and stator flux is
estimated to select the motor to be supplied, next. The advantage of the newly proposed DTC scheme over
the older DTC control scheme will be relevant, when the two motors are operating in different speeds and
loading conditions.
In this paper, a new algorithm for a DTC control scheme is suggested, based on selection of the
most appropriate inverter state vector. This paper is organized as follows. Section 2 describes the working
principle of the Nine-Switch Inverter. Section 3 explains, briefly, the DTC of the induction motor. Section 4
details the analytical studies revealing the properties of active vectors in the different operating conditions.
The proposed algorithm for driving two induction motors fed by the NSI will be detailed in Section 5.
Section 6 presents results and discussion.
2. THE NINE SWITCH INVERTER
The NSI has three lesser switches as compared to the classical dual output inverter, it has been
developed by replacing the middle six switches of the classical dual output Inverter by only three switches,
both inverters are shown in Figure 1.
Figure 1. (a) The classical Dual output inverter (b) The NSI
The NSI can be viewed as two two-level inverters operating in alternate manner, the upper six
switches constitute a classical six switch VSI, in the other hand, the six lower switches, also, constitute
another six switch VSI, hence, the middle three switches are shared between the two sub-inverters.
Originally, authors applied the Sinusoidal PWM control scheme, for each leg, the gate signal of the upper
switch is generated by comparing the upper half of a triangular carrier signal with a sinusoidal reference
signal. The gate signal of the lower switch is generated by comparing the lower half of the same triangular
carrier signal with another sinusoidal reference signal. In order to avoid closing the three switches of the
same leg simultaneously and therefore shorting the DC source, the gate signal of the middle switch is
generated by the output of a XOR logic gate whose inputs are the two gate signals for the upper and lower
switches, Figure 2 shows generated gate signals from a carrier signal and two reference signals.
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Figure 2. carrier signal, references signals and gate signals of the NSI using SPWM: (a) carrier signal and
references signals of upper and lower switches. (b) gate signal of the upper switch reference (c)gate signal of
the lower gate signal, (d) gate signal of the middle signal
Each of the three legs of the NSI , is composed of a three switches and only one switch is allowed to
be open, at time, in each leg, to avoid : 1- supplying two loads at the same time which will lead to loss of
independency of control. 2- keeping terminals of any of the two motors open-circuited, therefore, a
combination of 27 switching states are allowed in the control of the Nine Switch Inverter [18].
If two Y-connected loads are to be driven by the NSI, the peak fundamental phase voltage of each
load is given as follows:
Vanpeak(i) =
mi.Vin
2
(1)
To operate in the linear modulation region of the SPWM, the two reference signals are constrained
to stay within the horizontal band of the carrier signal without overlapping, therefore the following inequality
has to be, always, satisfied:
𝑚1 + 𝑚2 ≤ 1 (2)
The reference signals of the ith
load has the following form:
𝑉𝑟𝑒𝑓𝑖
= 𝐴𝑖. sin(2𝜋. 𝑓𝑖) + 𝑜𝑓𝑓𝑠𝑒𝑡𝑖 (3)
By manipulating amplitudes and offsets of both sinusoidal reference signals within the carrier signal
band, the percentage of use of the DC source is divided accordingly between the two loads. When applying
Space Vector Modulation [18], as it is the case of DTC control, a gain of 15% in the sum of modulation
indices, which translate to higher torque production, hence, the inequality condition in equation 2 becomes :
𝑚1 + 𝑚2 ≤
2
√3
(4)
3. DIRECT TORQUE CONTROL
3.1. Direct Torque Control Technique
The Direct Torque Control (DTC) has been introduced in the second half of the 1980s [19],[20],
although a relatively new control strategy, DTC has quickly gained industrial acceptance [21]. In the
conventional DTC scheme, the stator flux and the electromagnetic torque are controlled by proper selection
of inverter states vectors.
For proper operation of DTC control scheme, an accurate model for the induction motor is required,
since stator flux and the electromagnetic torque are estimated, based the motor model. The two-phase
dynamic model of IM in the stationary dq frame:
𝑉𝑠𝑑𝑞 = 𝑅𝑠𝑖𝑠𝑑𝑞 +
𝑑
𝑑𝑡
(𝜓𝑠𝑑𝑞)
𝑉𝑟𝑑𝑞 = 0 = 𝑅′𝑟𝑖𝑟𝑑𝑞 +
𝑑
𝑑𝑡
(𝜓𝑟𝑑𝑞) − 𝑗𝑤𝑟𝜓𝑟𝑑𝑞
𝜓𝑠𝑑𝑞 = 𝐿𝑠𝑖𝑠𝑑𝑞 + 𝐿𝑚𝑖𝑟𝑑𝑞
𝜓𝑟𝑑𝑞 = 𝐿𝑚𝑖𝑠𝑑𝑞 + 𝐿′𝑟𝑖𝑟𝑑𝑞 (5)
Derivative of stator flux is equal to the stator EMF, hence, stator flux magnitude strongly depends on stator
voltage.
𝑑
𝑑𝑡
(𝜓𝑠𝑑𝑞) = 𝑒𝑑𝑞 = 𝑉𝑠𝑑𝑞 − 𝑅𝑠𝑖𝑠𝑑𝑞 (6)
If voltage drop across Rs is ignored, stator flux can be controlled by stator voltage applied:
∆𝜓𝑠𝑑𝑞 = (𝑉𝑠𝑑𝑞)∆𝑡 (7)
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The developed torque is proportional to the sine of angle between stator and rotor flux vectors θsr
𝑇𝑒
⃗⃗⃗ =
3
2
𝑃
2
𝐿𝑚
𝜎𝐿𝑠𝐿′𝑟
𝜓𝑟
⃗⃗⃗⃗ ⊗ 𝜓𝑆
⃗⃗⃗⃗ (8)
|𝑇𝑒| =
3
2
𝑃
2
𝐿𝑚
𝜎𝐿𝑠𝐿′𝑟
|𝝍𝒓||𝝍𝑺| sin 𝜃𝑠𝑟 (9)
Angle of ψS
⃗⃗⃗⃗⃗⃗ is also dependent on stator voltage, hence, |Te| can also be controlled by applying the
proper vector to change θsr.
3.2. DTC speed mode control scheme
The DTC control scheme has two modes of operation, the DTC torque mode where motor torque is
controlled directly and the DTC speed mode where motor torque is controlled via motor speed. The DTC
speed mode control scheme is shown in Figure 3.
Figure 3. The DTC speed mode control scheme
In the DTC speed mode control scheme, three phase stator currents, stator voltages are measured,
motor speed is estimated or measured using an encoder. Stator flux magnitude and angle are estimated from
the obtained currents and voltages.
Measured or estimated speed and measured stator flux amplitude are compared with their respective
reference values. The stator flux error is fed directly to a hysteresis controller, where the motor speed error is
fed to a PI controller then the output of this latter is fed to another hysteresis controller. The output of
hysteresis controllers along with the stator flux angle will yield the proper vector to supply according to a
predefined switching table.
3.3. Adaptation of DTC control scheme for use with the NSI
For an independent control of the two loads, the NSI can only supply one of its two loads at a time,
when one load is supplied, the phases of the second load are short-circuited through one of the DC rails. In a
DTC point of view, when an active state vector is applied to the inverter composed of the upper six switches,
a zero vector is applied to the inverter composed of the six lower switches. While the effect of an active
vector on stator flux and torque depends on stator flux space vector position, the zero vector has little effect
on flux but it will reduce the torque [22]. This property justify the priority of controlling the torque over the
control of stator flux in the proposed algorithm.
In [15], authors suggested a DTC control scheme for two induction motors fed by the NSI as shown
in Figure 4, where the two motors are fed in alternate manner with equal time of supply, however, analytical
studies performed by [23], show that the rate of increase and the rate of decrease in both torque and stator
flux values are not equal for every two successive switchings and therefore controlling the two motors in
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alternate manner with 50% duty cycle, does not, necessarily, guarantee optimal results, as it will cause
asymmetry and high ripples.
Figure 4. The proposed DTC control scheme in [15] using the NSI
The control scheme proposed by authors is very similar to the conventional control scheme shown in
Figure 3, the only difference is that when a variable SA, SB and SC are assigned by the switching Table 1 the
synchronization block set all variable SX, SY and SZ to zero for 50% of the sampling time, for the other half
of the sampling time SA, SB and SC are set to one while SX, SY and SZ are assigned by the switching Table 2.
4. TORQUE AND STATOR FLUX RATES OF CHANGE
4.1. Rate of change in motor torque
In the conventional switching selection method [23], the increase and decrease in torque rates vary
with the speed of motor,
∆𝑇𝑒 ↑= [𝑃(𝜓𝑟
⃗⃗⃗⃗ ⊗ 𝑣𝑆
⃗⃗⃗ ) − 𝑃𝑤𝑟𝜓𝑠
⃗⃗⃗⃗ ° 𝜓𝑟
⃗⃗⃗⃗ − 𝑅𝑚𝑇𝑒]𝑇𝑓/𝐿σ (10)
∆𝑇𝑒 ↓= [−𝑃𝑤𝑟𝜓𝑠
⃗⃗⃗⃗ ° 𝜓𝑟
⃗⃗⃗⃗ − 𝑅𝑚𝑇𝑒]𝑇𝑓/𝐿σ (11)
Where Tf is the sampling period, ⊗ stands for vector product while ° denotes the scalar product and 𝑅𝑚 =
(𝐿𝑟𝑅𝑠 + 𝐿𝑠𝑅𝑟)/ 𝐿𝑚 ; 𝐿σ = (𝐿𝑠𝐿𝑟 − 𝐿𝑚
2
)/𝐿𝑚
The analysis can be summarized in the Table 1.
Table 1. Increase and decrease rates in Torque Vs Motor Speed [23]
Low speed region Medium speed region High Speed Region
Increase Vs Decrease in
Torque
|∆Te↑| >|∆Te↓| |∆Te↑| ≈ |∆Te↓| |∆Te↑| <|∆Te↓|
The asymmetry of torque ripple in the various speed regions, are shown in figures from the
experiments conducted by the same authors [23]. From the Table 1 and Figure 5, we can clearly notice that
driving the two loads with different speeds, will result in higher and asymmetrical torque errors, therefore,
supplying the two motors in alternate manner with an equal time of application will worsen the situation. The
proposed algorithm will supply the motor with the higher torque error.
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(a)
(b)
(c)
Figure 5 . Torque ripples in (a) Low Speed Region (b) Medium Speed Region (c) High Speed Region [23]
4.2. Rate of change in stator flux:
Given that the angle θ (θ ϵ [-30° to 30°]) which is defined as the angle between stator flux space
vector φ and the active vector Vk, the effect of the applied active vectors Vk+1 and Vk+2 on stator flux are
demonstrated in the Table 2 [23]. From the Table 2 and as illustrated in Figure 6, it is evident that selection
of vectors near the borders of the sectors will lead to a unbalanced change in stator flux error, which require
immediate selection of several active vectors to compensate for the change, therefore, supplying two motors
in an alternate fashion with an equal time of application will not help in restoring stator flux to its tolerable
values.
Table 2. Influence of vector Vs Stator flux space vector location
θ ≈ - 30° θ ≈ 30°
Vk+1 applied small increase large decrease
Vk+2 applied large increase small decrease
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Figure 6. Influence of vector Vs Stator flux space vector location
In the DTC control scheme, in the low speed region, the stator flux ripples are unacceptably high
[23]. Findings summarized in Table 2 can be exploited to reduce ripples by selecting the load whose vector
have the moderate effect on the stator flux. In other words, the load whose vector is closer to the center of the
sector being selected.
5. THE PROPOSED ALGORITHM
In order to reduce ripples of the electromagnetic torque and the stator flux in both motors and to
ensure a relatively higher switching frequency, the aforementioned facts, are exploited to develop a new
control scheme based on the following algorithm (Figure 7):
Figure 7. The Flow chart of the developed algorithm
For the reasons stated earlier, control of torque has been given higher priority over the control of
stator flux. If any one of the motors or both are having a high torque error, the load with the higher torque
error will be supplied by the inverter, in the other hand, if the torque errors of both loads, are acceptable, the
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load whose vector have the least influence on the stator flux change will be selected, in case of operation in
the low speed region. Otherwise, the selection is performed in an alternate manner.
Figure 8. Simulink®
Block diagram of the entire System
Figure 9. Synchronization Block and Matlab®
Function File
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6. RESULTS AND DISSCUSION
In order to demonstrate the indpendent control of both motors and to investigate the validity of the
proposed algorithm, Simulation using the Matlab/Simulink®
software is carried out. Two induction motors
are driven with different combinations of speed profiles (120, 300 rad/s), while applying a nominal torque
load (26 N.m) in each speed combination, the stator flux of both motor is set to 0.9 Wb.
In the low speed region, the stator flux of each motor has high ripples, this is one of the drawbacks
of the original DTC control scheme. the significant voltage drop in stator resistance leads to a poor estimation
of stator flux values, hence, a wrong state vector is applied. Several works [24]-[26] has been proposed to
have a better estimate of stator flux value. In our proposed control scheme, the algorithm will supply the
motor whose active vector has the moderate influence to mitigate the sharp increase of stator flux. Stator flux
of the two motors in shown in Figure 10.
(a)
(b)
Figure 10. Stator Flux magnitude of: (a) Motor 1. (b) Motor 2
At first, the speed of the two motors is set to 120 rad/sec in a time interval of 200 milliseconds, due
to this high acceleration rate, 120% of the nominal torque command is requested by the control system, to
reach the assigned speed in time. At time 0.4 seconds, a nominal load is coupled to both motors, the motors
torques are increased to keep both motors running at the assigned speed, a slight decrease is noticed (i.e a
steady state error < 1% of the nominal speed). In the medium speed region, the algorithm will control the NSI
to supply the load with the larger torque error, Figure 11 and Figure 12 show acceptable torque ripples.
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Figure 11. Motor 1 Torque Vs its reference value
Figure 12. Motor 2 Torque Vs its reference value
After driving both loads with a medium speed, the speed of the first load is increased up to 300
rad/sec while the second load is kept running at a medium speed, once again, 120% of the nominal is
produced at the first load to accelerate. a nominal load is applied afterward, Figures 11 and 12 show that the
torque ripples of the first load are slightly larger than those of the second load due to the difference in speeds.
On the other hand, less than 1% of steady state error is noticed in speeds of both loads. As stated earlier,
based on remarks from Table 1, the torque ripples of the first motor would be higher, if the older control
scheme is used.
The speed of the second load is increased to the nominal speed (300 rad/sec) at time 2.0 seconds, a
120% of nominal torque command is applied to accelerate, a nominal load is applied to both motors, ripples
in both stator flux and torque of each motor remains whithin limits, which ensures a good regulation of speed
of both motors as shown, in Figures 13 and 14.
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Figure 13. Motor 1 speed Vs its reference value
Figure 14. Motor 1 speed Vs its reference value
In the DTC speed mode, the speed of both motors are controlled instead of torques, this facts justify
the abrupt rise in torque when acceleration of any of the two motors is requested. A saturation unit is used in
the control scheme to avoid forcing the two motors to develop more than 120% of their nominal torque, In
practice, an anti-windup unit is added to the PI controller to compensate for the overshoot inherent in Integral
part of the controller [27],[28].
The advantage of the present DTC control scheme over the old DTC control scheme, is evident in
two instances, 1- when the two motors are loaded and running at low speeds, inaccurate estimation of stator
flux may occur and the alternate selection of active state vectors for the two motors will worsen the
performance as it would lead to an abrupt change in stator flux which require application of several active
vectors to re-establish stator flux to permissible values. 2- If the old DTC control is opted for, when one of
the motors is running at low speed and the other motor is running at high speed, the rate of decrease of torque
in the latter motor will be more significant, eventually, leading to abrupt decrease in its speed and a slow
response of this motor to reach the assigned speed.
The NSI has been already proposed in Hybrid Electric Vehicle (HEV) [29], similarly, a
comprehensive literature review of the DTC control scheme and its application in EV field is detailed in [30]
and as demonstrated in the present paper, the combination of DTC control with the use NSI makes it well
suited for use in Electric Vehicle EV and HEV applications. The use of the NSI as a substitute to two
separate two-level inverters, as shown in Figure 15, will help reduce the overall cost and energy consumption
of EVs.
12. Int J Pow Elec & Dri Syst ISSN: 2088-8694
Direct Torque Control of Two Induction Motors Using the Nine-Switch Inverter (Draoui Abdelghani)
1563
(a) (b)
Figure 14. Topology of: (a) Conventional EV (b) Suggested EV
7. CONCLUSION
In this paper, a new Direct Torque control has been developed to drive two induction motors,
independently, via the Nine-Switch Inverter. Simulation results show acceptable torque and stator flux
ripples for each motor, in different speed profiles. Further improvements can be made, by using the a motor
model which takes into account the iron core losses and optimal results can be obtained when more advanced
stator flux estimators are used. Being effective in driving two motors with different speed, the NSI has been
proved to be well suited for EVs applications.
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NUMENCLATURE
L’r : Rotor Inductance refered to the stator
R’r : Rotor Resistance refered to the stator
Rs : Stator Resistance
Ls : Stator Inductance
LM : Mutual Inductance
𝛹
⃗⃗ s : Stator Flux Space Vector
𝛹
⃗⃗ r : Stator Flux Space Vector
σ : Leakage coefficient.
Parameters of simulated motors:
Line to Line Voltage : 400 V
Number of pole pairs : 2 poles
Stator resistance : 1.37 Ω
Stator inductance : 0.1459 H
Rotor resistance : 1.1 Ω
Rotor inductance : 0.149 H
Mutual inductance : 0.141 H
Moment of Inertia : 0.1 Kg/m2