This document summarizes research on carrier shifting algorithms for mitigating circulating current in a diode-clamped multilevel inverter (MLI) driving an induction motor. It proposes phase shift (PS), phase disposition (PD), and phase opposition disposition (POD) carrier shifting pulse width modulation (PWM) techniques to reduce circulating current within each inverter phase leg. Simulation and experimental results show that the PD technique provides the best performance in terms of reducing circulating current and harmonics compared to PS and POD. The PD algorithm can reduce circulating current to ±Idc/6, whereas PS only reduces to ±Idc/2 and POD to ±Idc/3.
Grid connected pv system using 9 level flying capacitor multilevel inverterIAEME Publication
This document summarizes a research paper that proposes using a 9-level flying capacitor multilevel inverter to integrate a photovoltaic system into a power grid. A 9-level flying capacitor multilevel inverter can reduce harmonics and total harmonic distortion compared to conventional inverters. The system was simulated in Matlab/Simulink and includes a PV array, boost converter to increase the voltage, and the 9-level flying capacitor multilevel inverter connected to the grid. Key advantages of multilevel inverters are their ability to handle high power applications with reduced switching losses and lower output distortion.
Nowadays power electronics circuits are embedded to most of electrical application areas. This approached offers a great control mechanism with simple and easy circuit configuration. Switched Reluctance Motor (SRM) is one of the most recent apparatus which draws a great number of researchers’ interests. Previously several attempts are made to use the power converters as driver for SRM such as Voltage Source Inverter (VSI) and bridge converters. This paper presents an analysis study of three level inverter to control the SRM. The inverter is controlled using space vector modulation SVM. The aim of this paper is to report the use the multilevel inverter to be fed into the SRM. The implementation of the multilevel inverter is abl to reduce the Total Harmonics Distortion (THD). Performance comparison are made between the multilevel and previous power electronics circuits that applied to the SRM. The simulation results have been conducted by MATLAB/SIMULINK software.
ANALYSIS OF VARIOUS COMPENSATION DEVICES FOR POWER QUALITY IMPROVEMENT IN WIN...IAEME Publication
The document analyzes various compensation devices for power quality improvement in wind energy systems. It discusses three important compensating devices: the Dynamic Voltage Restorer (DVR), Unified Power Quality Conditioner (UPQC), and Distribution Static Compensator (DSTATCOM). It describes how each device works to mitigate common power quality issues like voltage sag, swell, and harmonics. Through modeling and analysis of how each device addresses these power quality problems, the document finds that the DSTATCOM performance is comparatively better and it is the most suitable device for power quality improvement in wind energy systems.
Analysis and simulation of multilevel inverter using multi carrier based pwmIAEME Publication
This document analyzes and simulates a multilevel inverter using multi-carrier based PWM control techniques. It describes a cascaded multilevel inverter topology with separate DC sources for each H-bridge. It discusses phase-shifted and level-shifted carrier based PWM methods and modulation techniques like IPD, POD, and APOD. MATLAB Simulink models are used to simulate 5-level and 7-level inverters using phase-shifted and level-shifted PWM. Total harmonic distortion results show that POD PWM provides the lowest distortion.
A comparative study of cascaded h bridge and reversing voltage multilevel inv...IAEME Publication
This document compares a cascaded H-bridge multilevel inverter topology to a proposed reversing voltage multilevel inverter topology. The cascaded H-bridge requires more components as the number of levels increases, making it less reliable. The proposed reversing voltage topology separates output voltage generation into level generation and polarity generation parts, requiring fewer switches. Specifically, a 7-level example of each topology is compared in terms of total harmonic distortion and number of components. The proposed topology is shown to require fewer components and produce lower THD than the cascaded H-bridge topology.
Design of Electric Drive for Vehicular Application Using Vector ControlIOSR Journals
This document describes the design of an electric drive system for a vehicular application using vector control. It proposes an induction motor fed by a three-phase voltage source inverter whose input comes from a boost converter. Indirect vector control is chosen as the control scheme due to its ability to provide fast and accurate torque control without needing rotor position sensors. Simulation results show the motor is able to achieve speed control within 2.5 seconds with less than 4% deviation from the reference speed.
TRANSIENT STABILITY ENHANCEMENT BY USING DSSC AND PSSIAEME Publication
Synchronous operation of generators in power system is required to supply continuous electricity to customers. Proper transient stability must be maintained for stable operation of power system. To enhance the transient stability of power system FACTS or D-FACTS technology can be used. In this paper, Distributed Static Series Compensator (DSSC) which, belongs to D-FACTS technology is used to enhance the transient stability of two-machine system with Power System Stabilizer (PSS) as an auxiliary controller and it is found that DSSC along with PSS is able to maintain required transient stability during severe three-phase to ground fault.
Grid connected pv system using 9 level flying capacitor multilevel inverterIAEME Publication
This document summarizes a research paper that proposes using a 9-level flying capacitor multilevel inverter to integrate a photovoltaic system into a power grid. A 9-level flying capacitor multilevel inverter can reduce harmonics and total harmonic distortion compared to conventional inverters. The system was simulated in Matlab/Simulink and includes a PV array, boost converter to increase the voltage, and the 9-level flying capacitor multilevel inverter connected to the grid. Key advantages of multilevel inverters are their ability to handle high power applications with reduced switching losses and lower output distortion.
Nowadays power electronics circuits are embedded to most of electrical application areas. This approached offers a great control mechanism with simple and easy circuit configuration. Switched Reluctance Motor (SRM) is one of the most recent apparatus which draws a great number of researchers’ interests. Previously several attempts are made to use the power converters as driver for SRM such as Voltage Source Inverter (VSI) and bridge converters. This paper presents an analysis study of three level inverter to control the SRM. The inverter is controlled using space vector modulation SVM. The aim of this paper is to report the use the multilevel inverter to be fed into the SRM. The implementation of the multilevel inverter is abl to reduce the Total Harmonics Distortion (THD). Performance comparison are made between the multilevel and previous power electronics circuits that applied to the SRM. The simulation results have been conducted by MATLAB/SIMULINK software.
ANALYSIS OF VARIOUS COMPENSATION DEVICES FOR POWER QUALITY IMPROVEMENT IN WIN...IAEME Publication
The document analyzes various compensation devices for power quality improvement in wind energy systems. It discusses three important compensating devices: the Dynamic Voltage Restorer (DVR), Unified Power Quality Conditioner (UPQC), and Distribution Static Compensator (DSTATCOM). It describes how each device works to mitigate common power quality issues like voltage sag, swell, and harmonics. Through modeling and analysis of how each device addresses these power quality problems, the document finds that the DSTATCOM performance is comparatively better and it is the most suitable device for power quality improvement in wind energy systems.
Analysis and simulation of multilevel inverter using multi carrier based pwmIAEME Publication
This document analyzes and simulates a multilevel inverter using multi-carrier based PWM control techniques. It describes a cascaded multilevel inverter topology with separate DC sources for each H-bridge. It discusses phase-shifted and level-shifted carrier based PWM methods and modulation techniques like IPD, POD, and APOD. MATLAB Simulink models are used to simulate 5-level and 7-level inverters using phase-shifted and level-shifted PWM. Total harmonic distortion results show that POD PWM provides the lowest distortion.
A comparative study of cascaded h bridge and reversing voltage multilevel inv...IAEME Publication
This document compares a cascaded H-bridge multilevel inverter topology to a proposed reversing voltage multilevel inverter topology. The cascaded H-bridge requires more components as the number of levels increases, making it less reliable. The proposed reversing voltage topology separates output voltage generation into level generation and polarity generation parts, requiring fewer switches. Specifically, a 7-level example of each topology is compared in terms of total harmonic distortion and number of components. The proposed topology is shown to require fewer components and produce lower THD than the cascaded H-bridge topology.
Design of Electric Drive for Vehicular Application Using Vector ControlIOSR Journals
This document describes the design of an electric drive system for a vehicular application using vector control. It proposes an induction motor fed by a three-phase voltage source inverter whose input comes from a boost converter. Indirect vector control is chosen as the control scheme due to its ability to provide fast and accurate torque control without needing rotor position sensors. Simulation results show the motor is able to achieve speed control within 2.5 seconds with less than 4% deviation from the reference speed.
TRANSIENT STABILITY ENHANCEMENT BY USING DSSC AND PSSIAEME Publication
Synchronous operation of generators in power system is required to supply continuous electricity to customers. Proper transient stability must be maintained for stable operation of power system. To enhance the transient stability of power system FACTS or D-FACTS technology can be used. In this paper, Distributed Static Series Compensator (DSSC) which, belongs to D-FACTS technology is used to enhance the transient stability of two-machine system with Power System Stabilizer (PSS) as an auxiliary controller and it is found that DSSC along with PSS is able to maintain required transient stability during severe three-phase to ground fault.
SRF CONTROLLED DVR FOR COMPENSATION OF BALANCED AND UNBALANCED VOLTAGE DISTUR...IAEME Publication
The growth of power electronictechnology in the field of electric power sector has caused a greater awarenesson the power quality of distribution systems. With the re-structuring of powersystems and with shifting trend towards distributed and dispersed generation,the issue of power quality is going to take newer dimensions. The presentresearch is to identify the prominent concerns in this area and hence themeasures that can enhance the quality of power. This paper investigates theproblems of voltage sag, swell and its severe impact on nonlinear loads,sensitive loads.
This document summarizes research that modified the stator winding of a 1-phase 4-pole induction motor with a starting capacitor used on a table drilling machine. The stator winding was changed to a 3-phase 6-pole configuration to simplify the motor's construction and reduce current, power consumption, and rotational speed. Testing showed the modified 3-phase motor drew an average of 3.56 amps less current, consumed 191.4 watts less power, and had a rotor rotational speed 499.7 rpm slower compared to the original 1-phase motor under loaded conditions. The modifications resulted in a motor that no longer required a starting capacitor or centrifugal switch for operation.
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.
Two parallel single phase rectifiers by using single phase to three phase ind...eSAT Journals
Abstract A single-phase to three-phase drive system composed of two parallel single-phase rectifiers, a three-phase inverter and an induction motor was proposed. The system combines two parallel rectifiers without the use of transformers. The system model and the control strategy, including the PWM technique, have been developed. The complete comparison between the proposed and standard configurations has been carried out in this paper. Compared to the conventional topology, the proposed system permits to reduce the rectifier switch currents, the THD of the grid current with same switching frequency or the switching frequency with same THD of the grid current and to increase the fault tolerance characteristics. In addition, the losses of the proposed system may be lower than that of the conventional counterpart. The initial investment of the proposed system (due to high number of semiconductor devices) cannot be considered a drawback, especially considering the scenario where the cited advantages justify such initial investment. The experimental results have shown that the system is controlled properly, even with transient and occurrence of fault
System for Better Synchronism in DFIG Wind Energy Conversion System Using SME...IOSR Journals
This document summarizes a study on using a superconducting magnetic energy storage (SMES) system to improve the synchronization and performance of a doubly fed induction generator (DFIG) wind energy conversion system during faults and disturbances. The SMES unit is connected to the point of common coupling and uses a hysteresis current controller and fuzzy logic controller to charge and discharge, helping regulate voltage and inject or absorb current. Simulation results showed the SMES unit improved the DFIG system's ability to ride through voltage sags and swells while maintaining synchronization with the grid.
LOW VOLTAGE RIDE - THROUGH CAPABILITY OF WIND FARMSEditor IJMTER
Nowadays wind turbines are generally required to offer ancillary services similar to those
provided by conventional generators. One of the most important services wind turbines must offer is
to stay connected to the grid in fault situations delivering the reactive current specified in the recent
grid codes. In this paper, FACTS solutions for fixed speed wind farms such as DVR (Dynamic
Voltage Restorer) are presented as well as classic control and crowbar solutions for variable speed
wind turbines.
IRJET- Phase Conversion of VFD based Induction MotorIRJET Journal
This document discusses using a variable frequency drive (VFD) to control the speed of a three-phase induction motor. A VFD allows the motor to operate at variable speeds, which can provide energy savings compared to operating at a single rated speed. The VFD converts incoming single-phase power to three-phase power using a rectifier to produce DC power, then an inverter uses pulse width modulation to generate a three-phase AC output that can be varied in frequency to control motor speed. This setup allows flexible control of the induction motor's speed while improving efficiency over constant speed operation.
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.
IRJET- Variable Frequency Drive Used in TreadmillIRJET Journal
This document summarizes the use of variable frequency drives in treadmills. It discusses how most treadmills previously used DC brush motors but these had issues like high failure rates and maintenance costs. The document then explores how using an AC motor with a variable frequency drive can improve on the limitations of DC motors. It provides details on how variable frequency drives work, including discussing the rectifier, DC bus, inverter and control circuit components. It also explains techniques like pulse width modulation and flux vector control that are used to control the speed of AC motors. The objectives of using a variable frequency drive in a treadmill are listed as energy savings, increased life of components, reduced noise and vibration, lower thermal and mechanical stresses, and
This document summarizes the design and simulation of an integral controller based load frequency control system. It first provides background on load frequency control and reasons for maintaining a constant system frequency. It then describes the load frequency control loop and area control error calculation. The objectives of load frequency control are given as maintaining a constant frequency against load changes and ensuring each area absorbs its own load changes while maintaining scheduled tie-line power flows. Finally, the document discusses SIMULINK models of single area and multi-area power systems used to simulate an integral controller based load frequency control approach.
Analysis of distance protection relay in presence of static synchronous compe...IAEME Publication
This document analyzes the impact of a Static Synchronous Compensator (STATCOM) on distance protection relays for transmission lines. It presents a simulation of a 400kV, 300km transmission line with a 100MVA STATCOM at the midpoint and distance relays at each end. The simulation shows that the STATCOM affects the impedance seen by the relays during faults, as it injects current and alters line parameters. Traditional relay settings based solely on line impedance may not operate correctly with a STATCOM present. The document discusses modeling of the transmission line, STATCOM, and distance relays in MATLAB/Simulink to study their performance under normal and fault conditions with the STATCOM.
The document summarizes a research paper that proposes using a Dynamic Voltage Restorer (DVR) to mitigate power quality issues like voltage sags and swells in three-phase distribution systems. It begins with an introduction to power quality problems and DVR technology. It then describes the components and operating principle of a DVR, including its voltage injection capabilities. The document focuses on a control algorithm for DVR based on Synchronous Reference Frame Theory (SRF), which extracts compensation voltages using PI controllers and reference signal generation. Simulation results evaluating the DVR's performance under voltage sag/swell conditions are also presented and discussed.
This document discusses speed control of a DC motor using a chopper (buck converter) and PI controller. A buck converter is used to vary the armature voltage of the separately excited DC motor, allowing control of motor speed. A PI controller is employed to remove delay and provide fast control by minimizing the error between the reference speed and actual motor speed measured by a tachogenerator. The complete system including DC motor, buck converter and PI controller is modeled in MATLAB/Simulink. Simulation results for motor parameters like speed, current and torque are analyzed to verify the speed control methodology.
Optimal placement of dstatcom in an indian power system for load andIAEME Publication
This document discusses using an artificial neural network approach to determine the optimal placement of a Distribution Static Compensator (DSTATCOM) in a 75-bus Indian power system to balance voltages affected by unbalanced loads. The neural network was trained using balanced voltages before loads and unbalanced voltages with loads as inputs and targets. It found that placing the DSTATCOM at bus 47 produced the lowest error and best balanced voltages across the system when unbalanced loads were connected at different buses. Simulations confirmed the DSTATCOM placement effectively balanced voltages at load buses and other buses affected by the unbalanced loads.
Lecture-2 : Applications of Power Electronicsrsamurti
This document discusses several applications of power electronics, including:
1) Motor drives and variable speed drives which use power electronics to vary motor speed in an efficient manner and save energy compared to throttling flow with a valve.
2) LED and CFL lighting which use power electronics for power factor correction, constant current regulation and dimming controls.
3) Domestic appliances like fans which now use electronic speed controls instead of wasteful resistive controls.
IRJET- Simulation of a Doubly Fed Induction Generator based Wind Energy C...IRJET Journal
This document discusses the simulation of a doubly fed induction generator (DFIG) based wind energy conversion system using MATLAB. Key points:
- DFIGs are commonly used in wind energy systems due to advantages like improved efficiency, active and reactive power control, and reduced converter costs.
- In a DFIG system, the stator is directly connected to the grid while the rotor is connected via power electronic converters. Field oriented control is used to control the DFIG.
- The paper presents the mathematical modeling of a DFIG and simulations run in MATLAB, showing outputs like stator current, rotor current, and output power.
- A floating capacitor bridge topology is proposed to control the voltage across the capacitor
IRJET- A Comparative Study of Control Algorithms for DSTATCOM for Harmonic El...IRJET Journal
The document compares two control algorithms, back propagation and synchronous reference frame theory, for controlling a DSTATCOM (dynamic voltage compensator) to compensate for reactive power and eliminate current harmonics from linear and non-linear loads. It simulates the DSTATCOM performance with each control algorithm under different load conditions. The back propagation algorithm uses load current measurements to estimate reference source currents, while synchronous reference frame theory transforms load currents between stationary and rotating coordinate systems to extract reference values. Simulation results show that with both control algorithms, the DSTATCOM is able to regulate voltage amplitude at the point of common coupling and reduce total harmonic distortion of source currents from non-linear loads.
Analysis and Simulation of Asynchronous Machine Connected with Load Accomplis...YogeshIJTSRD
This paper presents the simulation analysis of pulse width modulation based induction motor drive. The main objective of this paper is analysis of asynchronous machine with PWM fed inverter and harmonic analysis of active and reactive power as well as voltage and current. Space vector pulse width modulation technique is used in various industrial applications. Variation in voltage and frequency supply to ac drives is produced from a voltage source inverter and space vector PWM is used frequently now a day due to their easy understanding. This work is based on a SVPWM based induction motor based on space vector theory. The simulation is done on MATLAB software and the simulation results obtained and analyzed. Ms. Neetu Khunte | Mr. Abhijeet Lal | Mr. Abhishek Agrawal "Analysis and Simulation of Asynchronous Machine Connected with Load Accomplished with Chopper Control and PWM Based Inverter" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-4 , June 2021, URL: https://www.ijtsrd.compapers/ijtsrd41190.pdf Paper URL: https://www.ijtsrd.comengineering/electronics-and-communication-engineering/41190/analysis-and-simulation-of-asynchronous-machine-connected-with-load-accomplished-with-chopper-control-and-pwm-based-inverter/ms-neetu-khunte
Comparative analysis of a cascaded seven level and five level mli based distr...IAEME Publication
This document summarizes a research paper that compares a cascaded seven-level and five-level multilevel inverter-based distribution static synchronous compensator (DSTATCOM) for compensating harmonics and reactive power using reference frame theory. The paper presents the configuration of a DSTATCOM using a cascaded multilevel inverter with five levels and seven levels. It describes the operation and switching states of the five-level and seven-level inverters. It also discusses the reference current control strategy used, which generates the reference currents required to compensate load current harmonics and reactive power based on instantaneous real-power theory. The control scheme aims to maintain the DC bus voltage constant. The proposed DSTATCOM system is
Proposed PV Transformer-Less Inverter Topology Technique for Leakage Current ...IJPEDS-IAES
Importance and demand of using renewable energy is dramatically escalated globally. Hence, the use of renewable energy is going to touch in peak. This demand is varying according to the site choosing. For instance, Wind is preferable where air is following highly as well as solar recommended place is high sun ray reducing places. Especially, the renewable system is highly recommended for electrification issues where it’s possible to produce the electricity for fulfilling rural and remote areas electricity problem. The photovoltaic (PV) panel of connecting with transformer based system is popular where some limitations are occurred especially cost and weight. In contrast, in this paper is focusing these issues where the transformer-less inverter system is used. Here will discuss some transformer-based and transformer-less inverter topologies and the leakage current issue which is occurred when transformer-less inverter system is used. Moreover, here is proposed a topology for reducing the leakage current after doing switching technique in both 50% and 75% duty cycle where output voltage remains quite same.
In the proposed approach,instead of a conventional 3- Phase inverter a component minimized single pha se inverter is utilized which reduces the cost of the inverter,th e switching losses,and the complexity of interface circuits to generate logic signals. A performance comparison of the prop osed inverter fed drive with a conventional 3Phase inverter fed drive is also mode in terms of speed response and t otal harmonic distortion (THD) of the stator curren t. The proposed inverter fed IM drive is found acceptable consideri ng its cost reduction and other advantageous featur es. A general pulse width modulation (PWM) method for c ontrol of 1-phase inverters is presented. The vecto r PWM offers a simple method to select three or four vectors tha t effectively synthesize the desired output voltage,even in presence of voltage oscillations across the two dc-link capacit ors. The influence of different switching patterns on output voltage symmetry,current waveform,switching frequency and common mode voltage can be examined. The paper als o discusses how the use of the wye and delta connecti ons of the motor windings affects the implementatio n of the pulse width modulator.
IRJET- Five Level Inverter based Single Phase to Three Phase ConverterIRJET Journal
This document describes a five-level inverter based single phase to three phase power converter system. The system uses a bridge rectifier to convert the single phase AC input to DC, which is then fed to three inverters to generate three phase AC output. Each inverter uses pulse width modulation (PWM) and a multilevel topology to reduce total harmonic distortion (THD) in the output. An isolation transformer is used to provide isolation between the inverter outputs and allow connection of the three phase load. Simulation results showed the converter can power a three phase motor from a single phase supply with 13.41% THD, low enough for motor operation.
SRF CONTROLLED DVR FOR COMPENSATION OF BALANCED AND UNBALANCED VOLTAGE DISTUR...IAEME Publication
The growth of power electronictechnology in the field of electric power sector has caused a greater awarenesson the power quality of distribution systems. With the re-structuring of powersystems and with shifting trend towards distributed and dispersed generation,the issue of power quality is going to take newer dimensions. The presentresearch is to identify the prominent concerns in this area and hence themeasures that can enhance the quality of power. This paper investigates theproblems of voltage sag, swell and its severe impact on nonlinear loads,sensitive loads.
This document summarizes research that modified the stator winding of a 1-phase 4-pole induction motor with a starting capacitor used on a table drilling machine. The stator winding was changed to a 3-phase 6-pole configuration to simplify the motor's construction and reduce current, power consumption, and rotational speed. Testing showed the modified 3-phase motor drew an average of 3.56 amps less current, consumed 191.4 watts less power, and had a rotor rotational speed 499.7 rpm slower compared to the original 1-phase motor under loaded conditions. The modifications resulted in a motor that no longer required a starting capacitor or centrifugal switch for operation.
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.
Two parallel single phase rectifiers by using single phase to three phase ind...eSAT Journals
Abstract A single-phase to three-phase drive system composed of two parallel single-phase rectifiers, a three-phase inverter and an induction motor was proposed. The system combines two parallel rectifiers without the use of transformers. The system model and the control strategy, including the PWM technique, have been developed. The complete comparison between the proposed and standard configurations has been carried out in this paper. Compared to the conventional topology, the proposed system permits to reduce the rectifier switch currents, the THD of the grid current with same switching frequency or the switching frequency with same THD of the grid current and to increase the fault tolerance characteristics. In addition, the losses of the proposed system may be lower than that of the conventional counterpart. The initial investment of the proposed system (due to high number of semiconductor devices) cannot be considered a drawback, especially considering the scenario where the cited advantages justify such initial investment. The experimental results have shown that the system is controlled properly, even with transient and occurrence of fault
System for Better Synchronism in DFIG Wind Energy Conversion System Using SME...IOSR Journals
This document summarizes a study on using a superconducting magnetic energy storage (SMES) system to improve the synchronization and performance of a doubly fed induction generator (DFIG) wind energy conversion system during faults and disturbances. The SMES unit is connected to the point of common coupling and uses a hysteresis current controller and fuzzy logic controller to charge and discharge, helping regulate voltage and inject or absorb current. Simulation results showed the SMES unit improved the DFIG system's ability to ride through voltage sags and swells while maintaining synchronization with the grid.
LOW VOLTAGE RIDE - THROUGH CAPABILITY OF WIND FARMSEditor IJMTER
Nowadays wind turbines are generally required to offer ancillary services similar to those
provided by conventional generators. One of the most important services wind turbines must offer is
to stay connected to the grid in fault situations delivering the reactive current specified in the recent
grid codes. In this paper, FACTS solutions for fixed speed wind farms such as DVR (Dynamic
Voltage Restorer) are presented as well as classic control and crowbar solutions for variable speed
wind turbines.
IRJET- Phase Conversion of VFD based Induction MotorIRJET Journal
This document discusses using a variable frequency drive (VFD) to control the speed of a three-phase induction motor. A VFD allows the motor to operate at variable speeds, which can provide energy savings compared to operating at a single rated speed. The VFD converts incoming single-phase power to three-phase power using a rectifier to produce DC power, then an inverter uses pulse width modulation to generate a three-phase AC output that can be varied in frequency to control motor speed. This setup allows flexible control of the induction motor's speed while improving efficiency over constant speed operation.
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.
IRJET- Variable Frequency Drive Used in TreadmillIRJET Journal
This document summarizes the use of variable frequency drives in treadmills. It discusses how most treadmills previously used DC brush motors but these had issues like high failure rates and maintenance costs. The document then explores how using an AC motor with a variable frequency drive can improve on the limitations of DC motors. It provides details on how variable frequency drives work, including discussing the rectifier, DC bus, inverter and control circuit components. It also explains techniques like pulse width modulation and flux vector control that are used to control the speed of AC motors. The objectives of using a variable frequency drive in a treadmill are listed as energy savings, increased life of components, reduced noise and vibration, lower thermal and mechanical stresses, and
This document summarizes the design and simulation of an integral controller based load frequency control system. It first provides background on load frequency control and reasons for maintaining a constant system frequency. It then describes the load frequency control loop and area control error calculation. The objectives of load frequency control are given as maintaining a constant frequency against load changes and ensuring each area absorbs its own load changes while maintaining scheduled tie-line power flows. Finally, the document discusses SIMULINK models of single area and multi-area power systems used to simulate an integral controller based load frequency control approach.
Analysis of distance protection relay in presence of static synchronous compe...IAEME Publication
This document analyzes the impact of a Static Synchronous Compensator (STATCOM) on distance protection relays for transmission lines. It presents a simulation of a 400kV, 300km transmission line with a 100MVA STATCOM at the midpoint and distance relays at each end. The simulation shows that the STATCOM affects the impedance seen by the relays during faults, as it injects current and alters line parameters. Traditional relay settings based solely on line impedance may not operate correctly with a STATCOM present. The document discusses modeling of the transmission line, STATCOM, and distance relays in MATLAB/Simulink to study their performance under normal and fault conditions with the STATCOM.
The document summarizes a research paper that proposes using a Dynamic Voltage Restorer (DVR) to mitigate power quality issues like voltage sags and swells in three-phase distribution systems. It begins with an introduction to power quality problems and DVR technology. It then describes the components and operating principle of a DVR, including its voltage injection capabilities. The document focuses on a control algorithm for DVR based on Synchronous Reference Frame Theory (SRF), which extracts compensation voltages using PI controllers and reference signal generation. Simulation results evaluating the DVR's performance under voltage sag/swell conditions are also presented and discussed.
This document discusses speed control of a DC motor using a chopper (buck converter) and PI controller. A buck converter is used to vary the armature voltage of the separately excited DC motor, allowing control of motor speed. A PI controller is employed to remove delay and provide fast control by minimizing the error between the reference speed and actual motor speed measured by a tachogenerator. The complete system including DC motor, buck converter and PI controller is modeled in MATLAB/Simulink. Simulation results for motor parameters like speed, current and torque are analyzed to verify the speed control methodology.
Optimal placement of dstatcom in an indian power system for load andIAEME Publication
This document discusses using an artificial neural network approach to determine the optimal placement of a Distribution Static Compensator (DSTATCOM) in a 75-bus Indian power system to balance voltages affected by unbalanced loads. The neural network was trained using balanced voltages before loads and unbalanced voltages with loads as inputs and targets. It found that placing the DSTATCOM at bus 47 produced the lowest error and best balanced voltages across the system when unbalanced loads were connected at different buses. Simulations confirmed the DSTATCOM placement effectively balanced voltages at load buses and other buses affected by the unbalanced loads.
Lecture-2 : Applications of Power Electronicsrsamurti
This document discusses several applications of power electronics, including:
1) Motor drives and variable speed drives which use power electronics to vary motor speed in an efficient manner and save energy compared to throttling flow with a valve.
2) LED and CFL lighting which use power electronics for power factor correction, constant current regulation and dimming controls.
3) Domestic appliances like fans which now use electronic speed controls instead of wasteful resistive controls.
IRJET- Simulation of a Doubly Fed Induction Generator based Wind Energy C...IRJET Journal
This document discusses the simulation of a doubly fed induction generator (DFIG) based wind energy conversion system using MATLAB. Key points:
- DFIGs are commonly used in wind energy systems due to advantages like improved efficiency, active and reactive power control, and reduced converter costs.
- In a DFIG system, the stator is directly connected to the grid while the rotor is connected via power electronic converters. Field oriented control is used to control the DFIG.
- The paper presents the mathematical modeling of a DFIG and simulations run in MATLAB, showing outputs like stator current, rotor current, and output power.
- A floating capacitor bridge topology is proposed to control the voltage across the capacitor
IRJET- A Comparative Study of Control Algorithms for DSTATCOM for Harmonic El...IRJET Journal
The document compares two control algorithms, back propagation and synchronous reference frame theory, for controlling a DSTATCOM (dynamic voltage compensator) to compensate for reactive power and eliminate current harmonics from linear and non-linear loads. It simulates the DSTATCOM performance with each control algorithm under different load conditions. The back propagation algorithm uses load current measurements to estimate reference source currents, while synchronous reference frame theory transforms load currents between stationary and rotating coordinate systems to extract reference values. Simulation results show that with both control algorithms, the DSTATCOM is able to regulate voltage amplitude at the point of common coupling and reduce total harmonic distortion of source currents from non-linear loads.
Analysis and Simulation of Asynchronous Machine Connected with Load Accomplis...YogeshIJTSRD
This paper presents the simulation analysis of pulse width modulation based induction motor drive. The main objective of this paper is analysis of asynchronous machine with PWM fed inverter and harmonic analysis of active and reactive power as well as voltage and current. Space vector pulse width modulation technique is used in various industrial applications. Variation in voltage and frequency supply to ac drives is produced from a voltage source inverter and space vector PWM is used frequently now a day due to their easy understanding. This work is based on a SVPWM based induction motor based on space vector theory. The simulation is done on MATLAB software and the simulation results obtained and analyzed. Ms. Neetu Khunte | Mr. Abhijeet Lal | Mr. Abhishek Agrawal "Analysis and Simulation of Asynchronous Machine Connected with Load Accomplished with Chopper Control and PWM Based Inverter" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-4 , June 2021, URL: https://www.ijtsrd.compapers/ijtsrd41190.pdf Paper URL: https://www.ijtsrd.comengineering/electronics-and-communication-engineering/41190/analysis-and-simulation-of-asynchronous-machine-connected-with-load-accomplished-with-chopper-control-and-pwm-based-inverter/ms-neetu-khunte
Comparative analysis of a cascaded seven level and five level mli based distr...IAEME Publication
This document summarizes a research paper that compares a cascaded seven-level and five-level multilevel inverter-based distribution static synchronous compensator (DSTATCOM) for compensating harmonics and reactive power using reference frame theory. The paper presents the configuration of a DSTATCOM using a cascaded multilevel inverter with five levels and seven levels. It describes the operation and switching states of the five-level and seven-level inverters. It also discusses the reference current control strategy used, which generates the reference currents required to compensate load current harmonics and reactive power based on instantaneous real-power theory. The control scheme aims to maintain the DC bus voltage constant. The proposed DSTATCOM system is
Proposed PV Transformer-Less Inverter Topology Technique for Leakage Current ...IJPEDS-IAES
Importance and demand of using renewable energy is dramatically escalated globally. Hence, the use of renewable energy is going to touch in peak. This demand is varying according to the site choosing. For instance, Wind is preferable where air is following highly as well as solar recommended place is high sun ray reducing places. Especially, the renewable system is highly recommended for electrification issues where it’s possible to produce the electricity for fulfilling rural and remote areas electricity problem. The photovoltaic (PV) panel of connecting with transformer based system is popular where some limitations are occurred especially cost and weight. In contrast, in this paper is focusing these issues where the transformer-less inverter system is used. Here will discuss some transformer-based and transformer-less inverter topologies and the leakage current issue which is occurred when transformer-less inverter system is used. Moreover, here is proposed a topology for reducing the leakage current after doing switching technique in both 50% and 75% duty cycle where output voltage remains quite same.
In the proposed approach,instead of a conventional 3- Phase inverter a component minimized single pha se inverter is utilized which reduces the cost of the inverter,th e switching losses,and the complexity of interface circuits to generate logic signals. A performance comparison of the prop osed inverter fed drive with a conventional 3Phase inverter fed drive is also mode in terms of speed response and t otal harmonic distortion (THD) of the stator curren t. The proposed inverter fed IM drive is found acceptable consideri ng its cost reduction and other advantageous featur es. A general pulse width modulation (PWM) method for c ontrol of 1-phase inverters is presented. The vecto r PWM offers a simple method to select three or four vectors tha t effectively synthesize the desired output voltage,even in presence of voltage oscillations across the two dc-link capacit ors. The influence of different switching patterns on output voltage symmetry,current waveform,switching frequency and common mode voltage can be examined. The paper als o discusses how the use of the wye and delta connecti ons of the motor windings affects the implementatio n of the pulse width modulator.
IRJET- Five Level Inverter based Single Phase to Three Phase ConverterIRJET Journal
This document describes a five-level inverter based single phase to three phase power converter system. The system uses a bridge rectifier to convert the single phase AC input to DC, which is then fed to three inverters to generate three phase AC output. Each inverter uses pulse width modulation (PWM) and a multilevel topology to reduce total harmonic distortion (THD) in the output. An isolation transformer is used to provide isolation between the inverter outputs and allow connection of the three phase load. Simulation results showed the converter can power a three phase motor from a single phase supply with 13.41% THD, low enough for motor operation.
Closed Loop Speed Control of a BLDC Motor Drive Using Adaptive Fuzzy Tuned PI...IJERA Editor
Brushless DC Motors are widely used for many industrial applications because of their high efficiency, high
torque and low volume. This paper proposed an improved Adaptive Fuzzy PI controller to control the speed of
BLDC motor. This paper provides an overview of different tuning methods of PID Controller applied to control
the speed of the transfer function model of the BLDC motor drive and then to the mathematical model of the
BLDC motor drive. It is difficult to tune the parameters and get satisfied control characteristics by using normal
conventional PI controller. The experimental results verify that Adaptive Fuzzy PI controller has better control
performance than the conventional PI controller. The modeling, control and simulation of the BLDC motor have
been done using the MATLAB/SIMULINK software. Also, the dynamic characteristics of the BLDC motor (i.e.
speed and torque) as well as currents and voltages of the inverter components are observed by using the
developed model.
Enhancement of power quality using microprocessor based shunt active power fi...IJECEIAES
Power quality is the most significant factor of power sector. The end user equipment such as induction motor, inverters, rectifiers inject harmonics into power system that influences the quality of power delivered. The presence of harmonics forces the use of instantaneous reactive power theory to calculate instantaneous power that helps in finding the compensating currents to eliminate harmonics. The control action required by active filter is accomplished by STM32F303RET6 microcontroller. Single phase induction motor is used as a dynamic nonlinear load in one of the three phases and resistive loads on the other two phases. TRIAC based RC triggering circuit was used to control the single phase induction motor. This paper presents the simulation and hardware implementation of shunt active power filter for 3 phase 4 wire unbalanced system. The hardware results show that THD in the source side has been reduced from 50.7% to 9.6% by implementing the SAPF.
The trend in the motor applications is to reduce weight and volume by increasing the efficiency. Because of the advantage of high efficiency and high density, interest in brushless DC motors and drives is increasing. Unlike DC motors, the brushless DC (BLDC) motors require inverter circuit and position detector. In this paper, we deal with the optimization of the BLDC motor, the inverter, and the position detector. The inverter is optimized to be mounted on the BLDC motor. This paper deals primarily with the design and implementation aspects of the BLDC motor and the integrated drive circuit. Experimental results for the prototype of the BLDC motor with integrated dirve circuit in the laboratory are presented to validate the feasibility.
Investigation in Induction Motor Starting and Speed Control with Variable Fre...IRJET Journal
This document investigates induction motor starting and speed control using a variable frequency drive (VFD). It begins with an introduction to induction motors and why VFDs are commonly used for speed control. It then describes the components and operation of a basic VFD system, including the rectifier, DC link, and PWM inverter stages. The document presents the theoretical basis for induction motor speed control via frequency variation and discusses pulse width modulation techniques used in VFDs. Experimental results are referenced but not described. Overall, the document provides a high-level overview of using a VFD for induction motor starting and variable speed control.
Speed Control of Induction Motor Using Hysteresis MethodIRJET Journal
This document discusses speed control of an induction motor using a hysteresis control method. It begins with an abstract that outlines using hysteresis current control in the speed loop control design to optimize induction motor performance. It then discusses using an extended state observer to estimate disturbances and compensate the speed controller. The document provides background on induction motors, including details on their stator, squirrel cage and wound rotors. It also discusses using inverters like diode-clamped and flying-capacitor inverters to generate the AC voltages used to drive the motor.
1) The document discusses reducing commutation torque ripple in brushless DC motors (BLDCMs) through controlling the input voltage. BLDCMs experience torque ripple during commutation intervals that depends on speed.
2) It proposes using a single-ended primary inductor converter (SEPIC) circuit before the inverter to generate the desired DC link voltage and control commutation torque ripple. This allows fast adjustment of the voltage during non-commutation periods.
3) Simulation results show the proposed method using SEPIC reduces commutation torque ripple at both high and low speeds more effectively than conventional DC-DC converters through faster regulation of the DC voltage.
Analysis of Commutation Torque Ripple Minimization for Brushless DC Motor Bas...IJERA Editor
Brushless DC Motors (BLDCM) are widely used in automated industrial applications like Computer Numerical Control (CNC) machinery, aerospace applications and in the field of robotics.But it still suffers from commutation torque which mainly depends on speed and transient line commutation interval. BLDC MOTOR torque ripple causes increased acoustic noise and undesirable speed fluctuation. This paper presents a new circuit topology and dc link voltage current in the control strategy to keep incoming and outgoing phase currents changing at the same rate during commutation. In this paper dc-dc single ended primary inductor converter (SEPIC) a switch selection circuit are employed in front of inverter. In order to obtain the desired commutation voltage resulting in reduced commutation torque ripple. Compared with simulation result conventional system and proposed method can obtain desired voltage much faster and minimize commutation torque ripple more efficiently
A Novel Three Phase Multilevel Inverter with Single DC Link for Induction Mot...IJECEIAES
1) The document presents two configurations of a novel three-phase eleven-level multilevel inverter with a reduced number of switches for induction motor drive applications.
2) Configuration 1 uses separate DC sources for each phase, requiring 24 switches total. Configuration 2 uses a single common DC source for all three phases, also requiring 24 switches.
3) Both configurations are simulated in Matlab/Simulink. Results show the inverter produces a three-phase voltage of 600V peak-to-peak and supplies 50A to an induction motor, driving it at 1400rpm with 10N-m of torque.
Comparative Study of Fuzzy Logic Based Speed Control of Multilevel Inverter f...IJPEDS-IAES
This paper presents a comparative analysis of speed control of brushless DC motor (BLDC) drive fed with conventional two-level, three and five level diode clamped multilevel inverter (DC-MLI). The performance of the drive system is successfully evaluated using Fuzzy Logic (FL) based speed controller. The control structure of the proposed drive system is described. The speed and torque characteristic of conventional two-level inverter is compared with the three and five-level multilevel inverter (MLI) for various operating conditions. The three and five level diode clamped multilevel inverters are simulated using IGBT’s and the mathematical model of BLDC motor has been developed in MATLAB/SIMULINK environment. The simulation results show that the Fuzzy based speed controller eliminate torque ripples and provides fast speed response. The developed Fuzzy Logic model has the ability to learn instantaneously and adapt its own controller parameters based on disturbances with minimum steady state error, overshoot and rise time of the output voltage.
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Aerospace Engineering.
This document presents a study on mitigating torque ripple and detecting rotor position in brushless DC motors (BLDCs). It discusses how BLDCs are commonly used in applications that require variable speed control. The paper proposes a direct back electromotive force sensing method to determine rotor position without sensors. Simulation results using MATLAB/Simulink show that the proposed method reduces torque ripples to 0.078% and stator current ripple to 0.38%, improving BLDC motor performance. In conclusion, the direct back EMF sensing approach provides sensorless position detection over a wide speed range without requiring calculation of virtual neutral points.
A seven level cascaded multilevel dstatcom for compensation of reactive power...IAEME Publication
This document describes a seven-level cascaded multilevel DSTATCOM system for compensating reactive power and harmonics. It uses a cascaded H-bridge multilevel inverter with either phase shifted PWM or level shifted PWM modulation techniques. Simulation results show the system is able to compensate load current harmonics and reactive power, reducing the total harmonic distortion of source currents from 36.89% to 4.37% with a seven-level inverter using phase shifted PWM. The DSTATCOM provides unity power factor correction at the point of common coupling.
Power Quality Improvement Using Cascaded H-Bridge Multilevel Inverter Based D...IJERA Editor
Cascaded multilevel configuration of the inverter has the advantage of its simplicity and modularity over the
configurations of the diode-clamped and flying capacitor multilevel inverters. This paper presents a threephase,
five-level and seven level cascaded multilevel voltage source inverter based active filter for power line
conditioning to improve power quality in the distribution network. The DSTATCOM helps to improve the
power factor and eliminate the Total Harmonics Distortion (THD) drawn from a Non-Liner Diode Rectifier
Load (NLDRL). The compensation process is based on concept of p-q theory. A CHB Inverter is considered for
shunt compensation of a 11 kV distribution system. Finally a level shifted PWM (LSPWM) and phase shifted
PWM (PSPWM) techniques are adopted to investigate the performance of CHB Inverter. The results are
obtained through Matlab/Simulink software package.
This paper presents a novel simplied PWM technique to drive switched capacitor type multi-level inverter fed from isolated type DC-DC converter for distributed generation. Distributed generation (DG) is renowned power generation at point of utility with no environmental aects and reduces transmission line losses. Photo-voltaic system is considered as renewable energy source for DG and the low voltage from PV system is boosted to required voltage using an isolated type single-input multi-output (SIMO) DC-DC converter. DC output from isolated SIMO DC-DC converter is fed to switched capacitor type multi-level inverter (SC-MLI) to feed the AC load. Isolated SIMO DC-DC converter apart from boosting the DG output voltage, also eliminates the problem of voltage unbalancing in SC-MLI topology. Closed loop operation of SIMO DC-DC converter employs only single PI controller instead of three controllers was presented in this paper. Modes of operation of SC-MLI and Novel PWM switching pattern was explained. Simulation of proposed system was developed using MATLAB/SIMULINK software. The prototype was developed for the proposed system and hardware results are also shown.
1) The document describes a system for controlling the speed of a CUK converter-fed BLDC motor using a PI controller.
2) A CUK converter is used to provide power to the BLDC motor and PI control is applied to regulate the output voltage of the CUK converter in order to control the motor speed.
3) Simulation results show that the proposed PI controller is able to effectively control the motor speed while maintaining low current ripple and reducing torque ripples.
Improved performance of asd under voltage sag conditionsIAEME Publication
This document summarizes a research paper that proposes a new combination technique using a neutral linked Vienna rectifier and Z-source inverter to improve the performance of adjustable speed drives (ASDs) under voltage sag conditions. The technique aims to control voltage sags at the front end to prevent issues in the inverter at the back end. Simulation results show the proposed combination provides more stable DC link voltage and motor speed during sags compared to a normal rectifier and Z-source inverter alone. The research presents the design methodology, calculations, circuit diagram, and experimental waveforms that validate the improved ride through capability of the motor drive system using the neutral linked Vienna rectifier and Z-source inverter combination.
Similar to Carrier Shifting Algorithms for the Mitigation of Circulating Current in Diode Clamped MLI fed Induction Motor Drive (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.
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.
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.
More from International Journal of Power Electronics and Drive Systems (20)
Use PyCharm for remote debugging of WSL on a Windo cf5c162d672e4e58b4dde5d797...shadow0702a
This document serves as a comprehensive step-by-step guide on how to effectively use PyCharm for remote debugging of the Windows Subsystem for Linux (WSL) on a local Windows machine. It meticulously outlines several critical steps in the process, starting with the crucial task of enabling permissions, followed by the installation and configuration of WSL.
The guide then proceeds to explain how to set up the SSH service within the WSL environment, an integral part of the process. Alongside this, it also provides detailed instructions on how to modify the inbound rules of the Windows firewall to facilitate the process, ensuring that there are no connectivity issues that could potentially hinder the debugging process.
The document further emphasizes on the importance of checking the connection between the Windows and WSL environments, providing instructions on how to ensure that the connection is optimal and ready for remote debugging.
It also offers an in-depth guide on how to configure the WSL interpreter and files within the PyCharm environment. This is essential for ensuring that the debugging process is set up correctly and that the program can be run effectively within the WSL terminal.
Additionally, the document provides guidance on how to set up breakpoints for debugging, a fundamental aspect of the debugging process which allows the developer to stop the execution of their code at certain points and inspect their program at those stages.
Finally, the document concludes by providing a link to a reference blog. This blog offers additional information and guidance on configuring the remote Python interpreter in PyCharm, providing the reader with a well-rounded understanding of the process.
Redefining brain tumor segmentation: a cutting-edge convolutional neural netw...IJECEIAES
Medical image analysis has witnessed significant advancements with deep learning techniques. In the domain of brain tumor segmentation, the ability to
precisely delineate tumor boundaries from magnetic resonance imaging (MRI)
scans holds profound implications for diagnosis. This study presents an ensemble convolutional neural network (CNN) with transfer learning, integrating
the state-of-the-art Deeplabv3+ architecture with the ResNet18 backbone. The
model is rigorously trained and evaluated, exhibiting remarkable performance
metrics, including an impressive global accuracy of 99.286%, a high-class accuracy of 82.191%, a mean intersection over union (IoU) of 79.900%, a weighted
IoU of 98.620%, and a Boundary F1 (BF) score of 83.303%. Notably, a detailed comparative analysis with existing methods showcases the superiority of
our proposed model. These findings underscore the model’s competence in precise brain tumor localization, underscoring its potential to revolutionize medical
image analysis and enhance healthcare outcomes. This research paves the way
for future exploration and optimization of advanced CNN models in medical
imaging, emphasizing addressing false positives and resource efficiency.
The CBC machine is a common diagnostic tool used by doctors to measure a patient's red blood cell count, white blood cell count and platelet count. The machine uses a small sample of the patient's blood, which is then placed into special tubes and analyzed. The results of the analysis are then displayed on a screen for the doctor to review. The CBC machine is an important tool for diagnosing various conditions, such as anemia, infection and leukemia. It can also help to monitor a patient's response to treatment.
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.
KuberTENes Birthday Bash Guadalajara - K8sGPT first impressionsVictor Morales
K8sGPT is a tool that analyzes and diagnoses Kubernetes clusters. This presentation was used to share the requirements and dependencies to deploy K8sGPT in a local environment.
Optimizing Gradle Builds - Gradle DPE Tour Berlin 2024Sinan KOZAK
Sinan from the Delivery Hero mobile infrastructure engineering team shares a deep dive into performance acceleration with Gradle build cache optimizations. Sinan shares their journey into solving complex build-cache problems that affect Gradle builds. By understanding the challenges and solutions found in our journey, we aim to demonstrate the possibilities for faster builds. The case study reveals how overlapping outputs and cache misconfigurations led to significant increases in build times, especially as the project scaled up with numerous modules using Paparazzi tests. The journey from diagnosing to defeating cache issues offers invaluable lessons on maintaining cache integrity without sacrificing functionality.
Comparative analysis between traditional aquaponics and reconstructed aquapon...bijceesjournal
The aquaponic system of planting is a method that does not require soil usage. It is a method that only needs water, fish, lava rocks (a substitute for soil), and plants. Aquaponic systems are sustainable and environmentally friendly. Its use not only helps to plant in small spaces but also helps reduce artificial chemical use and minimizes excess water use, as aquaponics consumes 90% less water than soil-based gardening. The study applied a descriptive and experimental design to assess and compare conventional and reconstructed aquaponic methods for reproducing tomatoes. The researchers created an observation checklist to determine the significant factors of the study. The study aims to determine the significant difference between traditional aquaponics and reconstructed aquaponics systems propagating tomatoes in terms of height, weight, girth, and number of fruits. The reconstructed aquaponics system’s higher growth yield results in a much more nourished crop than the traditional aquaponics system. It is superior in its number of fruits, height, weight, and girth measurement. Moreover, the reconstructed aquaponics system is proven to eliminate all the hindrances present in the traditional aquaponics system, which are overcrowding of fish, algae growth, pest problems, contaminated water, and dead fish.
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/)
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- 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/)
Batteries -Introduction – Types of Batteries – discharging and charging of battery - characteristics of battery –battery rating- various tests on battery- – Primary battery: silver button cell- Secondary battery :Ni-Cd battery-modern battery: lithium ion battery-maintenance of batteries-choices of batteries for electric vehicle applications.
Fuel Cells: Introduction- importance and classification of fuel cells - description, principle, components, applications of fuel cells: H2-O2 fuel cell, alkaline fuel cell, molten carbonate fuel cell and direct methanol fuel cells.
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harmonic performance [8]. Out of the modulation strategies the space vector PWM gives greater fundamental
output voltage and improved harmonic performance of inverter.
The analysis of circulating current is more important in the AC motor drives application. It produces
between neutral point (N) of the motor and supply ground (G). The existence of shaft voltage, bearing damage,
etc are some of the major effect of circulating current.The concurrent switching of the series connected switches
creates high dv/dt across load terminals of inverter. The increase in circulating current affects motor insulation
and also the cables. In drive applications it may causes the electromagnetic interference (EMI) this noise causes
to trip the inverter drive [9]. It is very essential to limit the circulating current to certain boundary. A MLI can
reduce the circulating current. Output voltage of multilevel inverter will vary in small increments because of
the more number of switching states [10], it allows to mitigate the low frequency harmonics thereby the
switching loss will be reduced. Furthermore the circulating current can be reduced by reducing the dv/dt rate
[11]. The cascaded inverter is widely implemented for the industrial applications in the literature [12]-[13],
however the main drawback of this type of configuration is it requires isolation transformers on AC side and a
more number of DC sources. Among all the configurations present in multilevel inverter, the analysis of
circulating current is derived for the DC-MLI, which is the more frequent topology of the 3-level inverters. For
medium and high voltage AC drives, this topology can be connected directly to power system utility.
The effect of shaft voltage and it’s resulting current were studied by Alger in 1920’s [14]. Various
mechanical modifications in the system had been presented in the literature to eliminate the negative effects of
the circulating current over motor bearing, like cable type, passive filters and the type of the bearing. There are
two types of cables are available they are shielded type and unshielded type, the unshielded type of cable has
no impact on the circulating currents. Even shielded type of cables also has no impact on small rating motors,
in higher rated motors, the magnitude of circulating current is inversely proportional to the motor speed. P.
pairodamonchai [15] has given the procedure for designing and complications while designing passive filters.
There are 4 types of filters are available to eliminate the circulating current they are dv/dt filters (11 kW power
level) and dv/dt reactors (110 and 500 kW power levels), sinusoidal filters [16], and common-mode chokes
[17]. The elimination of bearing current is 30 to 90% [18]-[19] based on the type of the filter on large rating
motors and there is no impact [20] in small rating motors. Moreover the passive filters have more size and
weight penalties. There are two types of bearings are available insulated bearing [21]-[22] and hybrid bearing.
Insulated bearing eliminates 40 to 60% of the circulating current on small rating motors and 60 to 80% [23] on
large rating motors. Hybrid bearings give complete suppression of bearing currents in small motors not suitable
for the large motor applications [24].
Different PWM technique provides different values of circulating current in the inverter. In this paper
the circulating current suppression is proposed with the different modulation strategies. A three level DC-MLI
is designed to drive 400 V, three-phase induction motor. Sinusoidal PWM, PD-SPWM, POD-SPWM, PS-
SPWM techniques are implemented using a Matlab-2013b for the modulating index, ma=0.9 and switching
frequency of 1050 Hz. The partial elimination of circulating current implemented using FPGA-SPARTEN III
processor. The Simulation output and experimental results are provided to validate the circulating current in
three-level diode clamped inverter [DC-MLI].
2. EFFECT OF HIGH CIRCULATING CURRENTS
The circulating current can be defined as the current that exists between the application neutral
and ground.
ING =
IAN+IBN+ICN
3
(1)
The shaft voltage on the rotor side of the motor is induced due to common mode voltage with higher voltage
and frequency in modern PWM inverter. If the breakdown voltage of lubricant in the bearing of motor is lesser
then the induced shaft voltage, circulating current in larger value will be flow through the apparatus neutral
(N) and supply ground (G) [21].
ic = Cb
dVb
dt
(2)
ic = BVR. Cb
dVNG
dt
(3)
Where BVR is the bearing voltage ratio.
This circulating current cause the malfunctioning of the sensitive electronic equipment such as in
control systems, false tripping of the ground fault relays. In rotating electrical machines, this current damages
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the bearing which in turn damages the machine and also cause electromagnetic Interference.
The instantaneous current sum is called as the circulating current. The generation of circulating current can be
observed from the following Figure 2.
Figure 2. Circuit diagram of three-level NPC induction motor drive with circulating current
3. CARRIER SHIFTING ALGORITHMS
To generate the required PWM signal in the carrier based pulse width modulation, triangular carrier
wave is compared with the reference sine wave.
3.1. Single Carrier PWM
The SPWM is a one of the most popular modulation techniques in the voltage source inverter. In
Sinusoidal pulse width modulation, single triangular carrier wave is compared with the reference sine wave in
order to generate firing signals for switching of the power electronic devices. In the medium voltage
applications power dissipation is one of the most common problems. The open loop SPWM control method at
fundamental frequency is to minimize the switching losses.
3.2. Multi Carrier PWM
The multi carrier PWM technique is employed only for the multi-level inverter. This technique is used
to increase the efficiency of the inverter output. In this PWM technique the carrier waves are in two ways, they
are horizontal and vertical. The vertical carrier distribution techniques are classified into two configurations
they are Phase Disposition (PD), Phase opposition Disposition (POD), where horizontal distribution
arrangement is only one type and that is Phase Shift (PS) control technique.
3.2.1. Phase disposition (PD)
The phase disposition is one of the techniques in the multi carrier PWM. In this type of technique, the
number of carriers depends upon the number of levels in the inverter. The formula for knowing the number of
carriers is (m-1), where m is number of levels. All carriers should be in phase disposition (PD, the PD-PWM
is best suited for the NPC). We can observe this technique from the Figure 3(a).
.
Figure 3(a). Phase Disposition
3.2.2. Phase opposition disposition (POD)
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The number of carriers is (m-1), and all these carriers are in phase with zero reference. The carriers
those are above the zero reference are in phase, but the carriers below zero reference are in phase opposition.
The Figure 3(b) represents the POD technique.
Figure 3(b). Phase Opposition Disposition
3.2.3. Phase shift (PS)
The number of carriers is (m-1), and each carrier is shifted by an angle of 90 degree accordingly. The
Figure 3.2.3 represents the phase shift technique.
Figure 39(c). Phase Shift
4. ANALYSIS OF CIRCULATING CURRENT DEPENDS ON SWITCHING STATES
The circulating currents have been discussed for the different switching states available in the sections.
The circulating current can be stated as the current between the application neutral and the ground point of the
inverter. Magnitude of circulating current depends on the amount of the inverter input current.
In the balanced star connected load the sum of phase currents are zero.
The three-level NPC inverter produces different combinations of the phase current depends on the
switching states. There are 27 possible different switching states are available, each switching state has
different amount of circulating current. The state 1 produces the phase current of +Idc/2, 0 state produces 0A&
-1 state produces –Idc/2. All over 12 switching states produces ±Idc/6, 7 states produces zero circulating current,
6 states produce ±Idc/3& 2 states produce ±Idc/2. Some sample different switching states and their circulating
current shown in the Figure 4.
5. CIRCULATING CURRENT REDUCTION
The circulating current minimization can be done by avoiding the abnormal switching of inverter. The
PWM techniques like PD, POD, and PS can control the circulating current to such an extent, though the
controlling of switching operation is not possible. The above chapter gives the detailed analysis of the available
switching states and corresponding circulating current. From that analysis selecting the proper switching states
the circulating current can be minimized. In the partial reduction of circulating current can be eliminated up to
Idc/3(n-1) for n-level inverter. In the partial elimination the 3-level inverter allows the circulating current
magnitude of ±Idc/6. Harmonics is inversely proportional to the common mode voltage. This shows that the
reduction of harmonics can be achieved by eliminating the common mode voltage. Similarly the circulating
current is directly proportional to the harmonics. The amount of harmonics will decrease with the reduction of
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the circulating current. Different PWM techniques like PS, PD, POD will reduce the circulating current to such
an extent. The PS PWM technique eliminates only till the level of ±Idc/2. The PD technique will reduce the
circulating current till ±Idc/6.
The necessity to reduce the circulating current is more in order to protect the device from the failures.
Finally the POD algorithm will reduce the circulating current till ±Idc/3. By comparing all the above results the
best algorithm to reduce the circulating current is PD algorithm type. As we know already the circulating
current directly proportional to the harmonics. So the harmonic level in the PD technique is comparatively low
compared to all different algorithms.
6. SIMULATION RESULTS
The circulating current reduction for PD, POD, PS for 3-phase 3-level NPC-NLI has been simulated
using matlab simulink to supply the drive system with 2.2Kw, 1440 RPM induction motor. The machine
parameters are rated voltage =380V, rated current=5A, stator resistance=2.9Ω, rotor resistance=2.2Ω, stator
leakage induction=12mH, rotor leakage induction=12mH& mutual induction=290mH. An open loop v/f speed
control method is used to control the speed of the motor and DC-link set at 440V. Both the simulation and
experimental results are carried out for 1 KHz switching frequency and modulation index of 0.877 at 50 Hz.
The matlab simulation and experimental results for the partial elimination of circulating current at neutral is
shown in the Figure 6. In the following figures, the observation that can be made is what is the amount of
current is present and what is the amount of the circulating current eliminated. When compared to the three
different PWM techniques the PD technique provides good results in terms of the circulating current and in
terms of the harmonics. Ths is the partial elimination technique of the circulating current, with this complete
elimination is not possible in order to eliminate completely this technique is not valid. The simulation which
are provided in the Figure 6 are closely matching with the experimental results which are provided in
Figure 7.
7. EXPERIMENTAL RESULTS
In this section, theoretical and simulation results for a 1 KW load system are shown. All waveforms
shown in this section are captured from FPGA SPARTAN-III-3AN-XC3S400. The simulated MATLAB code
connected with FPGA board through System generated tool, which ensure the less computational complexity
environment [25]. Three phase three level IGBT based NPC inverter system was used to experimentally
investigate the performance of the proposed topology. Figure 7(a) shows the output voltage (b) shows the pulse
generation for the PD technique Figure 7(c) shows the circulating current. The following waveforms represent
the voltage output, pulse generation and circulating current respectively. The IGBT used here is IRG4BC20FD
with a fundamental frequency of 50 Hz and switching frequency of 1 kHz. The input DC bus voltage is 150V.
1 KW motor with 50 mH inductance and 15nF capacitance is used here. The circulating current mitigated using
the PD technique is ±Idc/6 and that can be observed from the following diagram and the performance of the
system is improved in terms of harmonics.
8. CONCLUSION
Premature failure of the bearings in the conventional two-level inverter is due to the induced
circulating current in it. Multi-level inverters have their intrinsic ability to lessen the circulating current.
Simulation and experimental results prove that the magnitude of the circulating current minimized to ±Idc/6,
and that has a minimum THD in the line voltage and currrent. A multi-level inverter eliminates the dv/dt in its
output voltage and therefore the circulating current will also gets reduced. In the conventional two level inverter
this operation is not possible and that cause the premature failure of the bearings. The proposed three different
PWM techniques will also decrease the cost of reduction. Thus when compared to the two level inverter the
multi-level inverters has lot of advantages in terms of leakage current and harmonics.
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Figure 4. Different Switching states and its Circulating Current
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(a) (b)
(c)
Figure 6. Simulation results (a) 3-level DC-MLI using PD (Idc/6) , (b) 3-level DC-MLI using POD (Idc/3),
(c) 3-level DC-MLI using PS (Idc/2)
Table 1. Result Comparision
PWM
technique
THD
Circulating
current
PD 51.36 +Idc/6
POD 59.82 +Idc/3
PS 89.48 +Idc/2
Figure 7. Experimental results for PD technique (a) Output voltage (50V/div) (b) pulse generation (2A/div)
(c) circulating current (2A/div)
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