This document discusses using a unified power flow controller (UPFC) with an adaptive neuro-fuzzy controller to damp low frequency oscillations (LFO) in a power system. It presents a linearized model of a single machine connected to an infinite bus power system with a UPFC. The UPFC consists of two voltage source converters that can independently control reactive power and the voltage amplitude and phase to influence power flow. Simulation results show the neuro-fuzzy controller provides better damping of LFO disturbances compared to a conventional lead-lag controller for the UPFC.
During Damping of Low Frequency Oscillations in Power Systems with Fuzzy UPFC...IJMER
This document summarizes a research paper about using an adaptive neuro-fuzzy controller for a unified power flow controller (UPFC) to damp low frequency oscillations (LFO) in a power system.
The key points are:
1. LFO can occur in power systems due to a lack of damping torque. Traditionally, power system stabilizers were used but FACTS devices like UPFC can also control power flow and provide damping.
2. An adaptive neuro-fuzzy controller is designed for the UPFC to damp LFO. The controller has 2 inputs of deviation in rotor angle and deviation in frequency. Simulation results show it provides good damping performance.
3. The performance of the neuro-fuzzy
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Static Sustenance of Power System Stability Using FLC Based UPFC in SMIB Powe...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
Optimal coordinated design of PSS and UPFC-POD using DEO algorithm to enhance...IJECEIAES
Low-frequency oscillations (LFO) are an inevitable problem of power systems and they have a great effect on the capability of transfer and power system stability. The power system stabilizers (PSSs) as well as flexible AC transmission system (FACTS) devices can help to damp LFO. The target of this study is to tackle the problem of a dual-coordinated design between PSS and unified power flow controller (UPFC) implementing the task of power oscillation damping (POD) controller in a single machine infinite bus (SMIB) system. So, dolphin echolocation optimization (DEO) technique is utilized as an optimization tool to search for optimal parameter tunings based on objective function for enhancing the dynamic stability performance for a SMIB. DEO an algorithm has a few parameters, simple rules, provides the optimum result and is applicable to a wide range of problems like other meta-heuristic algorithms. Use DEO gave the best results in damping LFO compared to particle swarm optimization (PSO) algorithm. From the comparison results between PSO and DEO, it was shown that DEO provides faster settling time, less overshoot, higher damping oscillations and greatly improves system stability. Also, the comparison results prove that the multiple stabilizers show supremacy over independent controllers in mitigationg LFO of a SMIB.
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.
Fuzzy coordination of facts controllers forSHRUTICH
1) This document presents a new fuzzy-coordination controller for coordinating FACTS controllers like UPFCs to damp oscillations in a multi-machine power system.
2) The controller first optimizes the parameters of traditional POD controllers for the FACTS devices, then uses a fuzzy logic controller to coordinate the inputs of the POD controllers based on power flows.
3) Digital simulations show the new fuzzy-coordination controller improves damping performance over a range of disturbances and operating conditions, and is robust to changes in system parameters. It coordinates the FACTS controllers to damp both local and inter-area oscillations in the power system.
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.
The document summarizes research on using a Dynamic Voltage Restorer (DVR) with a Z-Source Inverter (ZSI) to mitigate power quality issues for a welding load. It describes modeling a DVR system using MATLAB/Simulink to compensate for voltage sags, swells and total harmonic distortion (THD) injected at the source. Simulation results show the DVR is able to maintain a constant output voltage and current at the load during faults, regulating the voltage. The ZSI provides benefits like boosting the DC link voltage, reducing current and voltage ripples, and operating under short circuits. The control strategy uses sinusoidal pulse width modulation to generate gate pulses for the inverter.
During Damping of Low Frequency Oscillations in Power Systems with Fuzzy UPFC...IJMER
This document summarizes a research paper about using an adaptive neuro-fuzzy controller for a unified power flow controller (UPFC) to damp low frequency oscillations (LFO) in a power system.
The key points are:
1. LFO can occur in power systems due to a lack of damping torque. Traditionally, power system stabilizers were used but FACTS devices like UPFC can also control power flow and provide damping.
2. An adaptive neuro-fuzzy controller is designed for the UPFC to damp LFO. The controller has 2 inputs of deviation in rotor angle and deviation in frequency. Simulation results show it provides good damping performance.
3. The performance of the neuro-fuzzy
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Static Sustenance of Power System Stability Using FLC Based UPFC in SMIB Powe...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
Optimal coordinated design of PSS and UPFC-POD using DEO algorithm to enhance...IJECEIAES
Low-frequency oscillations (LFO) are an inevitable problem of power systems and they have a great effect on the capability of transfer and power system stability. The power system stabilizers (PSSs) as well as flexible AC transmission system (FACTS) devices can help to damp LFO. The target of this study is to tackle the problem of a dual-coordinated design between PSS and unified power flow controller (UPFC) implementing the task of power oscillation damping (POD) controller in a single machine infinite bus (SMIB) system. So, dolphin echolocation optimization (DEO) technique is utilized as an optimization tool to search for optimal parameter tunings based on objective function for enhancing the dynamic stability performance for a SMIB. DEO an algorithm has a few parameters, simple rules, provides the optimum result and is applicable to a wide range of problems like other meta-heuristic algorithms. Use DEO gave the best results in damping LFO compared to particle swarm optimization (PSO) algorithm. From the comparison results between PSO and DEO, it was shown that DEO provides faster settling time, less overshoot, higher damping oscillations and greatly improves system stability. Also, the comparison results prove that the multiple stabilizers show supremacy over independent controllers in mitigationg LFO of a SMIB.
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.
Fuzzy coordination of facts controllers forSHRUTICH
1) This document presents a new fuzzy-coordination controller for coordinating FACTS controllers like UPFCs to damp oscillations in a multi-machine power system.
2) The controller first optimizes the parameters of traditional POD controllers for the FACTS devices, then uses a fuzzy logic controller to coordinate the inputs of the POD controllers based on power flows.
3) Digital simulations show the new fuzzy-coordination controller improves damping performance over a range of disturbances and operating conditions, and is robust to changes in system parameters. It coordinates the FACTS controllers to damp both local and inter-area oscillations in the power system.
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.
The document summarizes research on using a Dynamic Voltage Restorer (DVR) with a Z-Source Inverter (ZSI) to mitigate power quality issues for a welding load. It describes modeling a DVR system using MATLAB/Simulink to compensate for voltage sags, swells and total harmonic distortion (THD) injected at the source. Simulation results show the DVR is able to maintain a constant output voltage and current at the load during faults, regulating the voltage. The ZSI provides benefits like boosting the DC link voltage, reducing current and voltage ripples, and operating under short circuits. The control strategy uses sinusoidal pulse width modulation to generate gate pulses for the inverter.
This document compares buck and boost converter topologies for use in photovoltaic power systems to maximize power extraction from solar panels. It finds that the boost converter is better suited as the PV interface as it can maintain continuous input current flow to the load. Simulation results show that a boost converter tracking the maximum power point of a PV array can increase the output voltage from 17.1V to 24.9V and deliver 60W of power to the load. The boost converter also performs well under varying temperature and solar irradiation conditions according to the simulations.
This document presents a study on using a fuzzy logic controlled D-STATCOM (distributed static compensator) to improve power quality in a power distribution system. A D-STATCOM equipped with an LCL passive filter is modeled and connected in parallel to an 11kV distribution system. Fuzzy logic control is implemented to regulate the D-STATCOM's reactive power injection and compensate for voltage sags and total harmonic distortion. Simulation results show the D-STATCOM improves the voltage profile under different fault conditions and reduces current THD from 43.43% to 0.73% when the LCL filter is used. The paper concludes the D-STATCOM effectively mitigates voltage sags and enhances power quality in the distribution
Close Loop Control of Induction Motor Using Z-Source InverterIJSRD
In this paper a new closed loop control of induction motor fed by a Z – source inverter based on the vector control or field oriented control strategy is presented. Induction motor is supplied by Z – source inverter, in the Z – source inverter the term Z denotes impedance which means a combination of L & C element which are cross connected. The Z-source inverter consists of a unique impedance network (or circuit) to couple the inverter main circuit to the power supply, hence providing great features that cannot be observed in the conventional voltage-source inverter and current-source inverters in which capacitor and inductor are used, respectively.In the field oriented control method or vector control method speed of the induction motor, torque & 3 phase stator current is given to the field oriented controller and gate pulses for the inverter is generated to obtain the desired operation of the induction motor.
Hearing loss is one of the most common human impairments. It is estimated that by year 2015 more
than 700 million people will suffer mild deafness. Most can be helped by hearing aid devices depending on the
severity of their hearing loss. This paper describes the implementation and characterization details of a dual
channel transmitter front end (TFE) for digital hearing aid (DHA) applications that use novel micro
electromechanical- systems (MEMS) audio transducers and ultra-low power-scalable analog-to-digital
converters (ADCs), which enable a very-low form factor, energy-efficient implementation for next-generation
DHA. The contribution of the design is the implementation of the dual channel MEMS microphones and powerscalable
ADC system.
POWER STABILITY ANALYSIS OF A TRANSMISSION SYSTEM WITH A UNIFIED POWER FLOW C...IJITE
The unified power quality conditioner is the equipment used for regulated voltage distortion and voltage
unbalance in a power system. UPFC can enhance the power to flow through the transmission system by
controlling the power flow and voltage stability of the transmission line within their limits. This paper
presents a control scheme and Theoretical derivation of the unified power flow conditioner and the
simulation results are compared and contrasted in detail. UPFC is a combination of shunt Active and
series active power filters. UPFC contains a DC link capacitor in a single-phase voltage source inverter
with two back to back connected, three-phase three-wire and three-phase four-wire are arranged. The
fundamental target of this work is to determine the causes and impacts of power quality problems,
specifically voltage sag, voltage swell, power factor, and Total Harmonics Distortion (THD) and enhance
the power quality of a transmission system by UPFC based Transformative Intrinsic Algorithm (TIA). The
Simulation of the proposed method is developed by Mat lab Simulink software, and the simulation result
shows, the proposed method gives better solutions to control the power imbalance in the distribution
system with its cost-effectiveness.
Enhancement for Power Quality in Distribution Side Using Custom Power DevicesIOSR Journals
1) The document discusses enhancing power quality in distribution systems using custom power devices like the Interline Unified Power Quality Conditioner (IUPQC).
2) It proposes using a Synchronous Reference Frame (SRF) control algorithm with a modified Phase Locked Loop (PLL) for generating gate signals to improve the IUPQC's performance under distorted voltage conditions.
3) The SRF method transforms voltage and current signals into rotating dq coordinates to extract fundamental frequency components, while the modified PLL improves determination of positive sequence system voltages for better filtering.
FLC based on static var compensator for power system transient stability enha...TELKOMNIKA JOURNAL
1. The document discusses using a fuzzy logic controller combined with a PI controller to control a static var compensator (SVC) for improving power system transient stability.
2. A two generator, three bus test system is used to compare the performance of the fuzzy-SVC controller versus a conventional PI-SVC controller under different fault conditions.
3. Simulation results show that for a single line to ground fault, both controllers perform similarly. However, for a more severe three line to ground fault, the fuzzy-SVC controller is able to damp oscillations faster and achieve stability more quickly than the PI-SVC controller due to its ability to handle nonlinear system dynamics.
The document describes using particle swarm optimization (PSO) to control an interline power flow controller (IPFC) installed on a power transmission system. An IPFC uses voltage source converters to inject active and reactive power into transmission lines, allowing control of power flows. The document presents a MATLAB/Simulink model of an IPFC on a 4-bus system. Optimal parameters for the IPFC (magnitude and angle of injected voltages) are determined using PSO to minimize transmission line losses. Simulations apply this method to the IEEE 30-bus test system. PSO helps find optimal IPFC settings to efficiently control power flows in the multi-line transmission system.
This document presents a power factor correction technique using average current-mode control for DC-DC boost converters. It uses a fuzzy logic controller to control the output voltage and PI controllers to correct the input current shape. The methodology section describes the circuit, including a rectifier, boost converter, and control blocks. It also discusses average current mode control, the simulation model built in MATLAB, and the design of the fuzzy logic controller with seven membership functions for both inputs and one output. The results section shows simulation waveforms demonstrating power factor correction with low input current harmonics and regulated output voltage. It concludes the fuzzy controller provides better dynamic response to load changes than PI control.
This paper presents a grid-connected photovoltaic (PV) interface for delivering both active and reactive powers. The PV interface employs H-bridge topology DC-DC converter and inverter with analog control technology. The power flow is controlled solely by the adjustable DC output voltage of the DC to DC converter. In order to evaluate the PV interface system’s performances, it is tested by delivering power to the grid with low pawer factor. The experimental results show that at 300W active load, the inverter could deliver the reactive power of 400VAR. The PV interface could also produce very low harmonic voltage and current distorsions. The laboratory measurements show that the total harmonic distortions of inverter output voltage and current are 0.46% and 0.05%, respectively.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
IRJET- Design and Development of Interleaved Boost Converter using Fuzzy ...IRJET Journal
This document summarizes a research paper that proposes the design and development of an interleaved boost converter using a fuzzy logic controller. Some key points:
- The interleaved boost converter is used to boost the output voltage from a solar PV system in an efficient way with low voltage stress and higher power transfer ratio.
- A fuzzy logic controller is implemented to control the interleaved boost converter using a fuzzy logic algorithm for maximum power point tracking of the solar PV system.
- Simulation results in MATLAB show that the fuzzy logic controller improves the performance of the interleaved boost converter by reducing output voltage and current ripple compared to an open loop system.
- The proposed converter and fuzzy logic control method provide benefits such
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.
Adaptive Modified Minimally Switched Hysteresis Controlled Shunt Active Power...idescitation
The main focus of this article is to investigate the
effects of Adaptive control on the switching frequency and
Total Harmonic Distortion of a modified, minimally switched
hysteresis controlled shunt active power filter. Reference
current generation was done using Instantaneous real and
reactive power algorithm. Pulses to the minimally switched
grid interactive inverter in which only two switches are
controlled at a time, had been generated using a modified
hysteresis current controller. Use of Modified Hysteresis
controller results in reducing the switching loses to one-third
but results in increase in current THD than the conventional
hysteresis controller. To overcome this, pulses to the modified
hysteresis controller were generated employing adaptive
control by modifying pulses from a conventional hysteresis
controller. Using adaptive control instantaneous switching
frequency was reduced and maintained nearly constant and
THD was brought to the limits specified by the standards,
thus overcoming the disadvantage of conventional and modified
hysteresis controller which has variable switching frequency.
A comparison of Modified Hysteresis controller with and
without Adaptive control has been made, to show the reduction
in THD. The system was simulated using MATLAB-
SIMULINK.
Design and Analysis of Adaptive Neural Controller for Voltage Source Converte...IDES Editor
Usually a STATCOM is installed to support power
system networks that have a poor power factor and often poor
voltage regulation. It is based on a power electronics voltagesource
converter. Various PWM techniques make selective
harmonic elimination possible, which effectively control the
harmonic content of voltage source converters. The distribution
systems have to supply unbalanced nonlinear loads transferring
oscillations to the DC-side of the converter in a realistic
operating condition. Thus, additional harmonics are modulated
through the STATCOM at the point of common coupling
(PCC). This requires more attention when switching angles are
calculated offline using the optimal PWM technique. This
paper, therefore, presents the artificial neural network model
for defining the switching criterion of the VSC for the
STATCOM in order to reduce the total harmonic distortion
(THD) of the injected line current at the PCC. The model takes
into the account the dc capacitor effect, effects of other possible
varying parameters such as voltage unbalance as well as
network harmonics. A reference is developed for offline
prediction and then implemented with the help of back
propagation technique.
Controlling power flow losses in upfc system using adaptive neuro fuzzy contr...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
This paper presents a method to improve transient stability and damping of low frequency oscillations in a multi-machine power system using adaptive neuro-fuzzy control of FACTS devices. A Simulink model of a three generator power system equipped with a UPFC is developed. Simulation results show that a UPFC controlled using an adaptive neuro-fuzzy inference system controller more effectively improves transient stability and damps power oscillations compared to using SSSC. The neuro-fuzzy controller is trained using a hybrid learning algorithm to tune its parameters online based on generator speed deviation and acceleration as inputs.
For the up-coming generations of power-supply systems, the load located area power-supply sources are an effective one, in terms of our requirements: simplicity, integrity, battery-backup, etc. This could follow the Normalization of power factor & Reducing THD% values on input current, which makes us to add an essential to include a power-factor correction unit at supply side in these new typical topologies. This Proposed architecture presents an integrated battery manage system which can also offers PF correction along with Galvanic-Isolation of battery in a humble single structure. [3] The proposed scheme has the reliable characters like increased efficiency, compact circuit and reduced costs associated with a traditional standalone multiple-stages UPS with PFC. This paper addresses the UPS action, the analysis and simulation results of Proposed UPS scheme.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Os alunos do 8o ano realizaram vários trabalhos sobre a água com o objetivo de sensibilizar para a sua preservação. Os trabalhos incluíram a monitorização do consumo doméstico de água, escrita sobre a água, pesquisa sobre o ciclo da água e a importância de preservar este recurso.
1) O documento discute a evolução dos meios de pagamento, do físico para o eletrônico, impulsionada pela tecnologia digital.
2) Cartões de crédito e débito estão substituindo formas físicas como moedas e cheques, respondendo por mais de 80% das compras online.
3) Novas tecnologias como NFC prometem tornar os pagamentos ainda mais rápidos e seguros através de dispositivos móveis.
This document compares buck and boost converter topologies for use in photovoltaic power systems to maximize power extraction from solar panels. It finds that the boost converter is better suited as the PV interface as it can maintain continuous input current flow to the load. Simulation results show that a boost converter tracking the maximum power point of a PV array can increase the output voltage from 17.1V to 24.9V and deliver 60W of power to the load. The boost converter also performs well under varying temperature and solar irradiation conditions according to the simulations.
This document presents a study on using a fuzzy logic controlled D-STATCOM (distributed static compensator) to improve power quality in a power distribution system. A D-STATCOM equipped with an LCL passive filter is modeled and connected in parallel to an 11kV distribution system. Fuzzy logic control is implemented to regulate the D-STATCOM's reactive power injection and compensate for voltage sags and total harmonic distortion. Simulation results show the D-STATCOM improves the voltage profile under different fault conditions and reduces current THD from 43.43% to 0.73% when the LCL filter is used. The paper concludes the D-STATCOM effectively mitigates voltage sags and enhances power quality in the distribution
Close Loop Control of Induction Motor Using Z-Source InverterIJSRD
In this paper a new closed loop control of induction motor fed by a Z – source inverter based on the vector control or field oriented control strategy is presented. Induction motor is supplied by Z – source inverter, in the Z – source inverter the term Z denotes impedance which means a combination of L & C element which are cross connected. The Z-source inverter consists of a unique impedance network (or circuit) to couple the inverter main circuit to the power supply, hence providing great features that cannot be observed in the conventional voltage-source inverter and current-source inverters in which capacitor and inductor are used, respectively.In the field oriented control method or vector control method speed of the induction motor, torque & 3 phase stator current is given to the field oriented controller and gate pulses for the inverter is generated to obtain the desired operation of the induction motor.
Hearing loss is one of the most common human impairments. It is estimated that by year 2015 more
than 700 million people will suffer mild deafness. Most can be helped by hearing aid devices depending on the
severity of their hearing loss. This paper describes the implementation and characterization details of a dual
channel transmitter front end (TFE) for digital hearing aid (DHA) applications that use novel micro
electromechanical- systems (MEMS) audio transducers and ultra-low power-scalable analog-to-digital
converters (ADCs), which enable a very-low form factor, energy-efficient implementation for next-generation
DHA. The contribution of the design is the implementation of the dual channel MEMS microphones and powerscalable
ADC system.
POWER STABILITY ANALYSIS OF A TRANSMISSION SYSTEM WITH A UNIFIED POWER FLOW C...IJITE
The unified power quality conditioner is the equipment used for regulated voltage distortion and voltage
unbalance in a power system. UPFC can enhance the power to flow through the transmission system by
controlling the power flow and voltage stability of the transmission line within their limits. This paper
presents a control scheme and Theoretical derivation of the unified power flow conditioner and the
simulation results are compared and contrasted in detail. UPFC is a combination of shunt Active and
series active power filters. UPFC contains a DC link capacitor in a single-phase voltage source inverter
with two back to back connected, three-phase three-wire and three-phase four-wire are arranged. The
fundamental target of this work is to determine the causes and impacts of power quality problems,
specifically voltage sag, voltage swell, power factor, and Total Harmonics Distortion (THD) and enhance
the power quality of a transmission system by UPFC based Transformative Intrinsic Algorithm (TIA). The
Simulation of the proposed method is developed by Mat lab Simulink software, and the simulation result
shows, the proposed method gives better solutions to control the power imbalance in the distribution
system with its cost-effectiveness.
Enhancement for Power Quality in Distribution Side Using Custom Power DevicesIOSR Journals
1) The document discusses enhancing power quality in distribution systems using custom power devices like the Interline Unified Power Quality Conditioner (IUPQC).
2) It proposes using a Synchronous Reference Frame (SRF) control algorithm with a modified Phase Locked Loop (PLL) for generating gate signals to improve the IUPQC's performance under distorted voltage conditions.
3) The SRF method transforms voltage and current signals into rotating dq coordinates to extract fundamental frequency components, while the modified PLL improves determination of positive sequence system voltages for better filtering.
FLC based on static var compensator for power system transient stability enha...TELKOMNIKA JOURNAL
1. The document discusses using a fuzzy logic controller combined with a PI controller to control a static var compensator (SVC) for improving power system transient stability.
2. A two generator, three bus test system is used to compare the performance of the fuzzy-SVC controller versus a conventional PI-SVC controller under different fault conditions.
3. Simulation results show that for a single line to ground fault, both controllers perform similarly. However, for a more severe three line to ground fault, the fuzzy-SVC controller is able to damp oscillations faster and achieve stability more quickly than the PI-SVC controller due to its ability to handle nonlinear system dynamics.
The document describes using particle swarm optimization (PSO) to control an interline power flow controller (IPFC) installed on a power transmission system. An IPFC uses voltage source converters to inject active and reactive power into transmission lines, allowing control of power flows. The document presents a MATLAB/Simulink model of an IPFC on a 4-bus system. Optimal parameters for the IPFC (magnitude and angle of injected voltages) are determined using PSO to minimize transmission line losses. Simulations apply this method to the IEEE 30-bus test system. PSO helps find optimal IPFC settings to efficiently control power flows in the multi-line transmission system.
This document presents a power factor correction technique using average current-mode control for DC-DC boost converters. It uses a fuzzy logic controller to control the output voltage and PI controllers to correct the input current shape. The methodology section describes the circuit, including a rectifier, boost converter, and control blocks. It also discusses average current mode control, the simulation model built in MATLAB, and the design of the fuzzy logic controller with seven membership functions for both inputs and one output. The results section shows simulation waveforms demonstrating power factor correction with low input current harmonics and regulated output voltage. It concludes the fuzzy controller provides better dynamic response to load changes than PI control.
This paper presents a grid-connected photovoltaic (PV) interface for delivering both active and reactive powers. The PV interface employs H-bridge topology DC-DC converter and inverter with analog control technology. The power flow is controlled solely by the adjustable DC output voltage of the DC to DC converter. In order to evaluate the PV interface system’s performances, it is tested by delivering power to the grid with low pawer factor. The experimental results show that at 300W active load, the inverter could deliver the reactive power of 400VAR. The PV interface could also produce very low harmonic voltage and current distorsions. The laboratory measurements show that the total harmonic distortions of inverter output voltage and current are 0.46% and 0.05%, respectively.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
IRJET- Design and Development of Interleaved Boost Converter using Fuzzy ...IRJET Journal
This document summarizes a research paper that proposes the design and development of an interleaved boost converter using a fuzzy logic controller. Some key points:
- The interleaved boost converter is used to boost the output voltage from a solar PV system in an efficient way with low voltage stress and higher power transfer ratio.
- A fuzzy logic controller is implemented to control the interleaved boost converter using a fuzzy logic algorithm for maximum power point tracking of the solar PV system.
- Simulation results in MATLAB show that the fuzzy logic controller improves the performance of the interleaved boost converter by reducing output voltage and current ripple compared to an open loop system.
- The proposed converter and fuzzy logic control method provide benefits such
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.
Adaptive Modified Minimally Switched Hysteresis Controlled Shunt Active Power...idescitation
The main focus of this article is to investigate the
effects of Adaptive control on the switching frequency and
Total Harmonic Distortion of a modified, minimally switched
hysteresis controlled shunt active power filter. Reference
current generation was done using Instantaneous real and
reactive power algorithm. Pulses to the minimally switched
grid interactive inverter in which only two switches are
controlled at a time, had been generated using a modified
hysteresis current controller. Use of Modified Hysteresis
controller results in reducing the switching loses to one-third
but results in increase in current THD than the conventional
hysteresis controller. To overcome this, pulses to the modified
hysteresis controller were generated employing adaptive
control by modifying pulses from a conventional hysteresis
controller. Using adaptive control instantaneous switching
frequency was reduced and maintained nearly constant and
THD was brought to the limits specified by the standards,
thus overcoming the disadvantage of conventional and modified
hysteresis controller which has variable switching frequency.
A comparison of Modified Hysteresis controller with and
without Adaptive control has been made, to show the reduction
in THD. The system was simulated using MATLAB-
SIMULINK.
Design and Analysis of Adaptive Neural Controller for Voltage Source Converte...IDES Editor
Usually a STATCOM is installed to support power
system networks that have a poor power factor and often poor
voltage regulation. It is based on a power electronics voltagesource
converter. Various PWM techniques make selective
harmonic elimination possible, which effectively control the
harmonic content of voltage source converters. The distribution
systems have to supply unbalanced nonlinear loads transferring
oscillations to the DC-side of the converter in a realistic
operating condition. Thus, additional harmonics are modulated
through the STATCOM at the point of common coupling
(PCC). This requires more attention when switching angles are
calculated offline using the optimal PWM technique. This
paper, therefore, presents the artificial neural network model
for defining the switching criterion of the VSC for the
STATCOM in order to reduce the total harmonic distortion
(THD) of the injected line current at the PCC. The model takes
into the account the dc capacitor effect, effects of other possible
varying parameters such as voltage unbalance as well as
network harmonics. A reference is developed for offline
prediction and then implemented with the help of back
propagation technique.
Controlling power flow losses in upfc system using adaptive neuro fuzzy contr...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
This paper presents a method to improve transient stability and damping of low frequency oscillations in a multi-machine power system using adaptive neuro-fuzzy control of FACTS devices. A Simulink model of a three generator power system equipped with a UPFC is developed. Simulation results show that a UPFC controlled using an adaptive neuro-fuzzy inference system controller more effectively improves transient stability and damps power oscillations compared to using SSSC. The neuro-fuzzy controller is trained using a hybrid learning algorithm to tune its parameters online based on generator speed deviation and acceleration as inputs.
For the up-coming generations of power-supply systems, the load located area power-supply sources are an effective one, in terms of our requirements: simplicity, integrity, battery-backup, etc. This could follow the Normalization of power factor & Reducing THD% values on input current, which makes us to add an essential to include a power-factor correction unit at supply side in these new typical topologies. This Proposed architecture presents an integrated battery manage system which can also offers PF correction along with Galvanic-Isolation of battery in a humble single structure. [3] The proposed scheme has the reliable characters like increased efficiency, compact circuit and reduced costs associated with a traditional standalone multiple-stages UPS with PFC. This paper addresses the UPS action, the analysis and simulation results of Proposed UPS scheme.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Os alunos do 8o ano realizaram vários trabalhos sobre a água com o objetivo de sensibilizar para a sua preservação. Os trabalhos incluíram a monitorização do consumo doméstico de água, escrita sobre a água, pesquisa sobre o ciclo da água e a importância de preservar este recurso.
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VILLAMAR es una empresa de ingeniería que ofrece servicios de diseño, construcción, mantenimiento e instalaciones eléctricas. Cuenta con un equipo de profesionales con experiencia en proyectos inmobiliarios, industriales y comerciales. Sus servicios incluyen cálculos estructurales, consultoría, administración de proyectos y condominios, y mantención general de edificios.
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El documento contrasta las consecuencias de elegir la mentira frente a la verdad. La mentira eventualmente lleva al engaño propio y cierra puertas, mientras que la verdad abre puertas infinitas y conduce a resultados justos, claros y tolerantes. Se insta al lector a elegir el camino de la verdad para evitar enredarse en mentiras y desviarse del corazón.
This document summarizes a research paper that examines using a Unified Power Flow Controller (UPFC) and Power System Stabilizer (PSS) to mitigate oscillations in a power system. The paper presents a control scheme for the UPFC damping controller and analyzes the results of using the controller to damp oscillations compared to using an advanced PSS alone. The document provides background on the UPFC, which uses voltage-sourced converters to control active and reactive power flows and can improve power transmission stability. It describes the basic operating principle of the UPFC and presents the configuration used in practical implementations with two back-to-back voltage sourced converters connected by a common DC link.
International Journal of Engineering and Science Invention (IJESI) inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online
International Journal of Engineering Research and Development is an international premier peer reviewed open access engineering and technology journal promoting the discovery, innovation, advancement and dissemination of basic and transitional knowledge in engineering, technology and related disciplines.
IRJET- Enhancement of Power Flow Capability in Power System using UPFC- A RevieWIRJET Journal
This document reviews the use of a Unified Power Flow Controller (UPFC) to enhance power flow capability in power systems. The UPFC is a flexible AC transmission system (FACTS) device that can control both real and reactive power flows on a transmission line. It consists of two voltage source converters connected by a DC link: a static synchronous compensator (STATCOM) and a static synchronous series compensator (SSSC). The STATCOM controls reactive power and the DC link voltage, while the SSSC injects a controlled AC voltage in series with the transmission line to vary the transmission line impedance and power flow. Simulation results show that a UPFC installed on the IEEE 5 bus test system can control power flows and
Load flow analysis with upfc under unsymmetrical fault conditionAlexander Decker
This document discusses load flow analysis with and without a Unified Power Flow Controller (UPFC) under different fault conditions in a six bus power system simulation model. The UPFC is a Flexible AC Transmission System (FACTS) device that can control parameters like voltage, impedance, and phase angle to control power flow. The study aims to improve transient stability of the six bus system by determining active and reactive power on load buses under different fault types both with and without the UPFC. The control scheme and operating principle of the UPFC are also explained.
Transient Stability of Power System using Facts Device-UPFCijsrd.com
This paper is based on Occurrence of a fault in a power system causes transients. To stabilize the system, The Flexible Alternating Current Transmission (FACTS) devices such as UPFC are becoming important in suppressing power system oscillations and improving system damping. The UPFC is a solid-state device, which can be used to control the active and reactive power.. By using a UPFC the oscillation introduced by the faults, the rotor angle and speed deviations can be damped out quickly than a system without a UPFC. The effectiveness of UPFC in suppressing power system oscillation is investigated by analyzing their oscillation in rotor angle and change in speed occurred in the two machine system considered in this work. A proportional integral (PI) controller has been employed for the UPFC. It is also shown that a UPFC can control independently the real and reactive power flow in a transmission line. A MATLAB simulation has been carried out to demonstrate the performance of the UPFC in achieving transient stability of the two-machine five-bus system.
Review of the UPFC Different Models in Recent YearsIJPEDS-IAES
Unified Power Flow Controller (UPFC) is one of the most intriguing and, potentially, the most versatile classes of Flexible AC Transmission Systems (FACTS) devices. The UPFC is a device which can control simultaneously tree parameters line impedance, voltage, phase angle and dynamic compensation of AC power system. In order to analyze its true effects on power systems, it is important to model its constraints, due to various ratings and operating limits. This paper reviews on the different models of UPFC used in recent years and gives sets of information for each model of the UPFC in AC transmission. Then the different models are compared and features of each model are examined.
Power Flow Control In A Transmission Line Using Unified Power Flow ControllerIJMER
This paper concentrates on FACT device UPFC which is used for powerflow control in the
transmission side. With the growing demand of electricity, it is not possible to erect new lines to face the
situation. Flexible AC Transmission System (FACTS) makes use of the thyristor controlled devices and optimally
utilizes the existing transmission network. One of such device is Unified Power Flow Controller (UPFC) on
which the emphasis is given in this present work. Real, reactive power, and voltage balance of the unified
power-flow control (UPFC) system is analyzed. A novel coordination controller is proposed for the UPFC.
The basic control method is such that the shunt converter controls the transmission line reactive power
flow and the dc-link voltage. The series converter controls the real power flow in the transmission line and
the UPFC bus voltages. Experimental works have been conducted to verify the effectiveness of the
UPFC in power flow control in the transmission line. The simulation model was done in
MATLAB/SIMULINK platform.
The document proposes an artificial bee colony (ABC) algorithm based neuro fuzzy controller (NFC) to improve the performance of a unified power quality conditioner (UPQC) in compensating for power quality issues like voltage sags. The NFC uses the error and change in error voltage as inputs to a neural network. The ABC algorithm is used to optimize the neural network output. This optimized output is then used to generate optimal fuzzy rules and calculate the discharging capacitor voltage from a bias voltage generator, replacing the DC link capacitor. Simulation results show the proposed ABC-NFC method performs better than ANFIS, ANN, FLC and NFC in compensating for voltage sags.
Pe 2010 25-10-a facts device distributed power flow controllerSudeepthg Sudeepth
The document describes a new type of Flexible AC Transmission System (FACTS) device called the Distributed Power Flow Controller (DPFC). The DPFC is derived from the Unified Power Flow Controller (UPFC) by eliminating the common DC link between converters and distributing multiple single-phase series converters along the transmission line. This allows active power exchange between converters through the line using third harmonic frequencies instead of a DC link. The DPFC has the same control capabilities as the UPFC but offers improved reliability due to redundancy of series converters and lower cost due to smaller, isolated converters without high voltage insulation requirements. Experimental results from a scaled DPFC prototype are also presented.
Pe 2010 25-10-a facts device distributed power flow controllerSudeepthg Sudeepth
The document describes a new type of Flexible AC Transmission System (FACTS) device called the Distributed Power Flow Controller (DPFC).
The DPFC is derived from the Unified Power Flow Controller (UPFC) by eliminating the common DC link between the shunt and series converters. Instead, active power is exchanged between the converters through the transmission line at the third harmonic frequency.
The DPFC employs distributed FACTS concepts using multiple single-phase series converters instead of a single three-phase series converter like in the UPFC. This provides redundancy to increase reliability. It also avoids the need for high voltage isolation between phases since the converters are single-phase and floating.
Experimental results from a scaled
UPFC in order to Enhance the Power System ReliabilityIJMER
This document discusses unified power flow controllers (UPFCs) and their ability to enhance power system reliability. It provides an overview of FACTS devices and describes how UPFCs can control parameters like impedance, voltage, and phase angle to regulate power flow. The document summarizes the components, control modes, and benefits of UPFCs, and discusses modeling a single-phase UPFC in MATLAB/Simulink to demonstrate power flow control and voltage injection capabilities.
A New Approach to Powerflow Management in Transmission System Using Interline...IJERA Editor
In this paper a new approach to power flow management in transmission system using interline Power Flow
Controller (IPFC) is proposed and model for IPFC is developed and simulate by MATLAB software. Interline
Power Flow Controller is a versatile device can be used to control power flows of a multi-line system or subnetworks
An Interline Power Flow Controller (IPFC) is a converter based FACTS controller for series
compensation with capability of controlling power flow among multi-lines within the same corridor of the
transmission line. It consists of two or more Voltage Source Converters (VSCs) with a common dc-link. Real
power can be transferred via the common dc-link between the VSCs and each VSC is capable of exchanging
reactive power with its own transmission system
Performance and Analysis of Reactive Power Compensation by Unified Power Flow...ijeei-iaes
The Unified Power Flow Controller (UPFC) is the most versatile of the FACTS controllers envisaged so far. The main function of the UPFC is to control the flow of real and reactive power by injection of a voltage in series with the transmission line. Both the magnitude and the phase angle of the voltage can be varied independently. Real and Reactive power flow control can allow for power flow in prescribed routes, loading of transmission lines close to their thermal limits and can be utilized for improving transient and small signal stability of the power system. In this paper UPFC is incorporated in a SMIB (Single Machine Infinite Bus) system and the response of SMIB system has been recorded with and without UPFC, thereafter the comparison of both the output has been done. When no UPFC is installed, real and reactive power through the transmission line cannot be controlled. This paper presents control and performance of UPFC intended for installation on that transmission line to control power flow. Installing the UPFC makes it possible to control amount of active power flowing through the line. Simulations are carried out using MATLAB software to validate the performance of the UPFC.
ANFIS Based UPQC for Power Quality ImprovementIJMTST Journal
Analysis of a three-phase three wire Unified Power Quality Conditioner (UPQC) controlled with Adaptive Neuro Fuzzy Inference System based controller is presented in this project. UPQC is a custom power device which is integrated by series and shunt active power filters (APF) sharing a common dc bus capacitor. The shunt and series APFs are realized with the help of three – phase, three leg voltage source converters that are sharing a common DC capacitor. The fundamental voltages, currents are extracted by modified synchronous reference frame technique; switching pulses for both the filters are generated by conventional hysteresis based controller. The capacitance voltage is balanced by ANFIS based controller. Performance of the ANFIS based control algorithm of shunt active filter with series active filter is evaluated in terms of eliminating the power quality problems in a three phase, three-wire distribution system with non-linear and unbalanced load conditions. Adaptive neuro fuzzy logic control is used for dc capacitance balancing. System taken for test and the control algorithm are implemented with the help of Sim power systems and ANFIS editor of MATLAB / SIMULINK.
Nonlinear Control of UPFC in Power System for Damping Inter Area OscillationsIJMER
This document summarizes a research paper about using nonlinear control of Unified Power Flow Controllers (UPFCs) to damp inter-area oscillations in power systems. The paper proposes a nonlinear control method where UPFCs can control their interface bus angles to mitigate power system oscillations. The control method develops a reduced nonlinear model of the network and uses selected frequency measurements from a subset of dominant machines as inputs to FACTS controllers. The effectiveness of using this method with UPFCs to damp inter-area oscillations is validated on a test power system.
International Journal of Engineering Research and DevelopmentIJERD Editor
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This document provides a review of the Unified Power Flow Controller (UPFC), a type of Flexible AC Transmission System (FACTS) device. It discusses the basic components and operating principles of the UPFC, which combines the functions of a STATCOM and SSSC to control active and reactive power flow. The UPFC consists of two voltage source converters connected back-to-back via a DC link. One converter injects a voltage in series with the transmission line to control power flow while the other exchanges reactive power with the line to regulate the DC link voltage. Control schemes for both converters are described. The document also presents Simulink models of the UPFC and concludes it is effective for improving power system stability
Design of UPQC with Minimization of DC Link voltage for the Improvement of Po...IDES Editor
This document describes a proposed design for a Unified Power Quality Conditioner (UPQC) that uses fuzzy logic control to minimize DC link voltage fluctuations and improve power quality. The UPQC combines series and shunt inverters to compensate for voltage sags/swells, unbalanced voltages, harmonics, and reactive power. Fuzzy logic controllers are used to stabilize the DC link voltage and balance active power between the inverters. Simulation results show the fuzzy logic control provides better DC link voltage regulation compared to PI control, improving the UPQC's ability to compensate for power quality issues.
This document describes simulations carried out on Distributed Power-Flow Controller (DPFC) technology. Key points:
- DPFC is derived from Unified Power Flow Controller (UPFC) but eliminates the common DC link between shunt and series converters. Active power is exchanged through the transmission line using third-harmonic frequency components.
- DPFC has advantages over UPFC of lower cost due to lower component ratings/isolation for series converter, and higher reliability due to redundancy of series converters.
- Detailed simulations were performed on a two-machine system to illustrate DPFC's control features and ability to increase power transfer capability and improve system reliability compared to conventional systems. Laboratory tests validated the DPFC operating principle and
1. A.V.Sudhakara Reddy, M. Ramasekhara Reddy, Dr. M. Vijaya Kumar / International Journal
of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.1560-1565
Stability Improvement During Damping of Low Frequency
Oscillations with Fuzzy Logic Controller
A.V.Sudhakara Reddy1, M. Ramasekhara Reddy 2, Dr. M. Vijaya Kumar3
1
(M. Tech, Department of Electrical & Electronics Engg, JNTUACE, Pulivendula, A.P, India.)
2
(Assistant Professor, Department of Electrical & Electronics Engg, JNTUACE, Pulivendula, A.P, India.)
3
( Professor, Department of Electrical & Electronics Engg, JNTUACE, Anantapur, A.P, India.)
Abstract
Low Frequency Oscillations (LFO) transmission system near their limits. Thus, the
occur in power systems because of lack of the occurrence of the LFO has increased. FACTs
damping torque in order to dominance to power Controllers has capability to control network
system disturbances as an example of change in conditions quickly and this feature of FACTs can be
mechanical input power. In the recent past used to improve power system stability. The UPFC
Power System Stabilizer (PSS) was used to damp is a FACTS device that can be used to the LFO. The
LFO. FACTs devices, such as Unified Power primarily use of UPFC is to control the power flow
Flow Controller (UPFC), can control power flow, in power systems. The UPFC consists of two
reduce sub-synchronous resonance and increase voltage source converters (VSC) each of them has
transient stability. So UPFC may be used to two control parameters namely me, δe ,mb and δb
damp LFO instead of PSS. UPFC damps LFO [3]. The UPFC used for power flow control,
through direct control of voltage and power. A enhancement of transient stability, mitigation of
comprehensive and systematic approach for system oscillations and voltage regulation [3]. A
mathematical modelling of UPFC for steady- comprehensive and systematic approach for
state and small signal (linearize) dynamic studies mathematical modelling of UPFC for steady-state
has been proposed. The other modified linearize and small signal (linearized) dynamic studies has
Heffron-Philips model of a power system been proposed in [4-7]. The other modified
installed with UPFC is presented. For systems linearized Heffron-Philips model of a power system
which are without power system stabilizer (PSS), installed with UPFC is presented in [8] and [9]. For
excellent damping can be achieved via proper systems which are without power system stabilizer
controller design for UPFC parameters. By (PSS), excellent damping can be achieved via
designing a suitable UPFC controller, an proper controller design for UPFC parameters. By
effective damping can be achieved. In this designing a suitable UPFC controller, an effective
research the linearize model of synchronous damping can be achieved. It is usual that Heffron-
machine (Heffron-Philips) connected to infinite Philips model is used in power system to study
bus (Single Machine-Infinite Bus: SMIB) with small signal stability. This model has been used for
UPFC is used and also in order to damp LFO, many years providing reliable results [10]. In recent
adaptive neuro-fuzzy controller for UPFC is years, the study of UPFC control methods has
designed and simulated. Simulation is performed attracted attentions so that different control
for various types of loads and for different approaches are presented for UPFC control such as
disturbances. Simulation results show good Fuzzy control [11-14], conventional lead-lag
performance of neuro-fuzzy controller in control, Genetic algorithm approach, and Robust
damping LFO. control methods .
In this case study, the class of adaptive
Keywords – Neuro-Fuzzy Controller, Low networks that of the same as fuzzy inference system
Frequency Oscillations (LFO), Unified Power in terms of performance is used. The controller
Flow Controller (UPFC), Single Machine-Infinite utilized with the above structure is called Adaptive
Bus (SMIB). Neuro Fuzzy Inference System or briefly ANFIS.
Applying neural networks has many advantages
I. INTRODUCTION such as the ability of adapting to changes, fault
Flexible AC Transmission Systems, called tolerance capability, recovery capability, High-
FACTS, got in the recent years a well known term speed processing because of parallel processing and
for higher controllability in power systems by ability to build a DSP chip with VLSI Technology.
means of power electronic devices. Several FACTS- To show performance of the designed adaptive
devices have been introduced for various neuro-fuzzy controller, a conventional lead-lag
applications worldwide. The growth of the demand controller that is designed in is used and the
for electrical energy leads to loading the simulation results for the power system including
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2. A.V.Sudhakara Reddy, M. Ramasekhara Reddy, Dr. M. Vijaya Kumar / International Journal
of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.1560-1565
these two controllers are compared with each other. III.OPERATING PRINCIPLE OF UPFC
The following Section, the model of the power In the presently used practical
system including UPFC is presented. The proposed implementation, The UPFC consists of two
Adaptive Neuro-Fuzzy controller and lead-lag switching converters, which in the implementations
compensator are explained in Section III. The considered are voltage source inverters using gate
results of the simulation are finally given in Section turn-off (GTO) thyristor valves, as illustrated in the
IV. Finally conclusions are presented in section V. Fig 2.1. These back to back converters labeled
“Inverter 1 and “Inverter 2” in the figure are
II. MODEL OF THE POWER SYSTEM operated from a common dc link provided by a dc
INCLUDING UPFC storage capacitor.
UPFC is one of the famous FACTs devices This arrangement functions as an ac to ac
that is used to improve power system stability. Fig.1 power converter in which the real power can freely
shows a single machine- infinite-bus (SMIB) system flow in either direction between the ac terminals of
with UPFC. It is assumed that the UPFC the two inverters and each inverter can
performance is based on pulse width modulation independently generate (or absorb) reactive power
(PWM) converters. In figure 1 me, mb and δe, δb are at its own ac output terminal.
the amplitude modulation ratio and phase angle of
the reference voltage of each voltage source
converter respectively. These values are the input
control signals of the UPFC.
Fig. Basic circuit arrangement of unified power
flow controller
The basic function of inverter 1 is to
supply or absorb the real power demanded by
Inverter 2 at the common dc link. This dc link
power is converted back to ac and coupled to the
transmission line via a shunt-connected transformer.
Fig.1 A single machine connected to infinite bus Inverter 1 can also generate or absorb controllable
with UPFC reactive power, if it is desired, and there by it can
provide independent shunt reactive compensation
As it mentioned previously, a linearized for the line.
model of the power system is used in dynamic
studies of power system. In order to consider the
effect of UPFC in damping of LFO, the dynamic
model of the UPFC is employed; In this model the
resistance and transient of the transformers of the
UPFC can be ignored. The Linearized state variable
equations of the power system equipped with the
UPFC can be represented as [8].
Fig2.Principle configuration of an UPFC
The UPFC consists of a shunt and a series
transformer, which are connected via two voltage
source converters with a common DC-capacitor.
The DC-circuit allows the active power exchange
between shunt and series transformer to control the
phase shift of the series voltage. This setup, as
shown in Figure 1.21, provides the full
controllability for voltage and power flow. The
series converter needs to be protected with a
Where ΔmE, ΔmB , ΔδE and ΔδB are the Thyristor bridge. Due to the high efforts for the
deviation of input control signals of the UPFC. Also Voltage Source Converters and the protection, an
in this study IEEE Type- ST1A excitation system UPFC is getting quite expensive, which limits the
was used. practical applications where the voltage and power
flow control is required simultaneously.
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3. A.V.Sudhakara Reddy, M. Ramasekhara Reddy, Dr. M. Vijaya Kumar / International Journal
of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.1560-1565
IV. CONTROLLER DESIGN These are called normalized firing strengths. Then f
I. Lead-Lag Controller Design can be written as
As mentioned before, in this study two f = w¯1f1+......+ w20f20 (5)
different controllers have been used to damp LFO.
The first one is conventional lead-lag controller. It The above relation is linear with respect to
consists of gain block, washout block, lead-lag pi , qi, ri and i=1,…,20. So parameters can be
compensator block. The washout block is categorized into 2 sets: set of linear parameters and
considered as a high-pass filter, with the time set of nonlinear parameters. Now Hybrid learning
constant TW. Without this block steady changes in algorithm can be applied to obtain values of
input would modify the output. The value of TW is parameters. Hybrid learning algorithm is
not critical and may be in the range of 1 to 20 combination of linear and nonlinear parameters
seconds. In this study, the parameters obtained from learning algorithm. Description for learning
lead-lag controller design that is presented in, were procedure can be found in . This network is called
used. adaptive by Jang and it is functionally equivalent to
Sugeno type of a fuzzy system. It is not a unique
II. Adaptive Neuro-Fuzzy Controller Design presentation. With regard to the explanations
Another controller is adaptive neuro-fuzzy presented and with the help of MATLAB software,
controller. In this section, we will present the adaptive neuro-fuzzy controller can be designed.
procedure of designing of the adaptive neuro-fuzzy The rules surface for designed controller is
controller. In this research, the neuro fuzzy shown in figure 3.The membership functions for
controller has 2 inputs that are Δδ and Δω and it has input variable ∆𝜔 are presented in figure 4.
1 output that is f ∈ {∆𝑚E, ∆𝛿 E, ∆𝑚B, ∆𝛿 B }. For
each input 20 membership functions and also 20
rules in the rules base is considered. Figure 5
demonstrates the structure of adaptive neuro-fuzzy
controller for a sugeno fuzzy model with 2 inputs
and 20 rules.
Fig.3 The rules surface
Fig.3 ANFIS architecture for a two-input Sugeno
fuzzy model with 20 rules
In Figure 3, a Sugeno type of fuzzy system has the
rule base with rules such as follows:
1. If Δδ is A1 and Δω is B1 then f1=p1 Δδ+q1
Δω+r1.
2. If Δδ is A2 and Δω is B2 then f2=p2 Δδ+q2
Δω+r2. 𝜇 𝐴 𝑖 and 𝜇 𝐵 𝑖 are the membership functions
of fuzzy sets Ai and Bi for i=1,…,20. In evaluating
the rules, we choose product for T-norm (logical
and). Then controller could be designed in
following steps: Fig.4 The membership functions for input variable
1. Evaluating the rule premises: ∆𝜔
𝑤 𝑖 = 𝜇 𝐴 𝑖 (Δ𝛿) 𝜇 𝐵 𝑖 (∆𝜔), i= 1.....20
(2) One of the advantages of using neuro-
2.Evaluating the implication and the rule fuzzy controller is that we can utilize one of the
consequences: designed controllers for instance Δme controller in
𝑤 1 ∆𝛿,∆𝜔 𝑓1 (∆𝛿,∆𝜔 )+⋯+𝑤 20 (∆𝛿 ,∆𝜔 )𝑓 20 (∆𝛿 ,∆𝜔 ) place of the other controllers. While if we use
f(∆𝛿, ∆𝜔) =
𝑤 1(∆𝛿 ,∆𝜔 ) +⋯+𝑤 20(∆𝛿 ,∆𝜔 ) conventional lead-lag controllers, for each control
Or leaving the arguments out parameters, a controller must be designed.
𝑤 𝑓 +⋯+𝑤 20 𝑓20
f = 11 (3)
𝑤 1 +⋯+𝑤 20 V. SIMULATION RESULTS
This can be separated to phases by first defining In this research, two different cases are
𝑤𝑖
w¯i = 𝑤 +⋯+𝑤 studied. In the first case mechanical power and in
1 20
(4) the second case reference voltage has step change
and deviation in ω (Δω) and deviation in rotor angle
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of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.1560-1565
δ (Δδ) is observed. The parameter values of system
are gathered in Appendix. In first case, step change
in mechanical input power is studied. Simulations
are performed when mechanical input power has
10% increase (ΔPm=0.1 pu) at t=1 s. Simulation
results for different types of loads and controllers (
ΔmE, ΔδE, ΔmB, ΔδB ) and step change in
mechanical input power are shown in figures 5 to 9.
Figure 5.5
Generator Parameters :
M = 2H = 8.0MJ /MVA , D = 0.0, Td0’ = 5.044S
Xd = 1.0pu , Xq = 0.6 , Xd „ = 0.3
Exciter (IEEE Type ST1): 𝑘 𝐴 = 100, TA = 0.01S
Reactances: XIE = 0.1 pu , XE = XB =0.1 pu,
XBv = 0.3 pu, XE = 0.5 pu
Operation Condition: Pe = 0.8 pu, Vt = Vb=1.0 pu
UPFC parameters: mE = 0.4013, mB = 0.0789 ,
δE = -85.3478° , δB = -78.2174°
DC link: Vdc = 2 pu, Cdc = 1 pu Figure 5.6
Results with Lead-Lag controller : Results with Fuzzy controller :
Figure 5.1 Figure 6.1
Figure 5.2 Figure 6.2
Figure 5.3 Figure 6.3
Figure 5.4 Figure 6.4
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5. A.V.Sudhakara Reddy, M. Ramasekhara Reddy, Dr. M. Vijaya Kumar / International Journal
of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.1560-1565
conventional lead-lag compensator and the
proposed neuro-fuzzy controller for the UPFC
indicates that the proposed neuro-fuzzy controller
has less settling time and less overshoot in
comparison with the conventional lead-lag
compensator. Hence the performance of system can
be improved i.e., another way stability of power
system can be improved with fuzzy controller.
Figure 6.5
V. CONCLUSIONS
With regard to UPFC capability in
transient stability improvement and damping LFO
of power systems, an adaptive neuro-fuzzy
controller for UPFC was presented in this paper.
The controller was designed for a single machine
infinite bus system. Then simulation results for the
system including neuro-fuzzy controller were
compared with simulation results for the system
Figure 6.6 including conventional lead-lag controller.
Simulations were performed for different kinds of
loads. Comparison. showed that the proposed
adaptive neuro-fuzzy controller has good ability to
reduce settling time and reduce amplitude of LFO.
Also we can utilize advantages of neural networks
such as the ability of adapting to changes, fault
tolerance capability, recovery capability, High-
speed processing because of parallel processing and
Figure 7. FIS Editor ability to build a DSP chip with VLSI Technology.
Fuzzy logic is a convenient way to map an input
Fig 5.1 & 6.1 shows angular velocity space to an output space. Mapping input to output is
deviation during step change in mechanical input the starting point for everything. Hence stability of
power for nominal load (me Controller). Fig 5.2 & the system can be improved.
6.2 shows angular velocity deviation during step
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