At present the Renewable energy resources (RES) are being increasingly connected in distribution systems utilizing power electronic converters. This paper presents a novel control strategy for achieving maximum benefits from these grid-interfacing inverters when installed in 3-phase 4-wire distribution systems. The inverter is controlled to perform as a multi-function device by incorporating active power filter functionality. The inverter can thus be utilized as power converter to inject power generated from RES to the grid and shunt APF to compensate current unbalance, load current harmonics, load reactive power demand and load neutral current. All of these functions may be accomplished either individually or simultaneously. With such a control, the combination of grid-interfacing inverter and the 3-phase 4-wire linear/non-linear unbalanced load at point of common coupling appears as balanced linear load to the grid. This new control concept is demonstrated with extensive MATLAB/Simulink simulation studies and validated through digital signal processor-based laboratory experimental results.
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
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
Power Quality Improvement at Distribution Level for Grid Connected Renewable ...IJERA Editor
The non-linear load current harmonics may result in voltage harmonics and can create a serious PQ problem in
the power system network. Active power filters (APF) are extensively used to compensate the load current
harmonics and load unbalance at distribution level. This results in an additional hardware cost. However, in this
project it has incorporated the features of APF in the conventional inverter interfacing renewable with the grid,
without any additional hardware cost. Here, the main idea is the maximum utilization of inverter rating which is
most of the time underutilized due to intermittent nature of RES. The grid-interfacing inverter can effectively be
utilized to perform the four important functions they are to transfer active power harvested from the renewable
resources (wind, solar, etc.), load reactive power demand support, current harmonics compensation at PCC and
current unbalance and neutral current compensation in case of 3-phase 4-wire system. Moreover, with adequate
control of grid-interfacing inverter, all the four objectives can be accomplished either individually or
simultaneously. The PQ constraints at the PCC can therefore be strictly maintained within the utility standards
without additional hardware cost.
With such a control, the combination of grid-interfacing inverter and the 3-phase 4-wire linear/non-linear
unbalanced load at point of common coupling appears as balanced linear load to the grid. This new control
concept is demonstrated with extensive MATLAB/Simulink simulation studies
A CONTROL APPROACH FOR GRID INTERFACING INVERTER IN 3 PHASE 4 WIRE DISTRIBUT...IJMER
With the increase in load demand, the Renewable Energy Sources (RES) are
increasingly connected in the distribution systems which utilizes power electronic
Converters/Inverters. Nowadays, 3-phase 4-wire distribution power system has been widely used in
residential and office buildings, manufacturing facilities, schools etc This paper presents a novel
control strategy for achieving maximum benefits from the grid-interfacing inverters when installed in
3-phase 4-wire distribution systems. The inverter can thus be utilized as: 1) power converter to inject
power to the grid, and 2) shunt APF to compensate current unbalance, load current harmonics and
load neutral current. All of these functions may be accomplished either individually or
simultaneously. This new control concept is demonstrated with extensive MATLAB/Simulink
simulation studies
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
A Novel control of a Grid-Interfacing Inverter to Improve the Quality of Powe...IJERA Editor
Renewable energy resources (RES) are being increas- ingly connected in distribution systems utilizing power electronic converters. This paper presents a novel control strategy for achieving maximum benefits from these grid-interfacing inverters when installed in 3-phase 4-wire distribution systems. The inverter is controlled to perform as a multi-function device by incorporating active power filter functionality. The inverter can thus be utilized as: 1) power converter to inject power generated from RES to the grid, and 2) shunt APF to compensate current unbalance, load current harmonics, load reactive power demand and load neutral current. All of these functions may be accomplished either individually or simultaneously. With such a control, the combination of grid-interfacing inverter and the 3-phase 4-wire linear/non-linear unbalanced load at point of common coupling appears as balanced linear load to the grid. This new control concept is demonstrated with extensive MATLAB/Simulink simulation studies and validated through digital signal processor-based laboratory experimental results.
Power Quality Improvement of Grid Interconnection of renewable Energy Based D...IJERA Editor
This paper presents a grid interfacing inverter which compensates power quality problems and also interface Renewable Energy Sources with the help of electric grid. Renewable Energy Sources are being increasingly connected in distribution system utilizing power electronic converters. Grid interfacing inverter can be used: 1) To improve the transfer of active power harvested from RES; 2) To meet load reactive power demand support ; 3) To reduce current harmonics by incorporating the current harmonic compensator at point of common coupling(PCC) ; 4) current unbalance and neutral current compensation in case of 3-phase 4-wire system. The fuzzy logic can be used in many applications especially, when the process/models are complex to analyse by using classical methods. Mainly fuzzy logic controller is used to control DC capacitor voltage. Simulations are carried out using MATLAB/SIMULINK to verify the performance of the controller. The output shows the controller has fast dynamic response high accuracy of tracking DC voltage reference and robust to load parameters variations.
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
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
Power Quality Improvement at Distribution Level for Grid Connected Renewable ...IJERA Editor
The non-linear load current harmonics may result in voltage harmonics and can create a serious PQ problem in
the power system network. Active power filters (APF) are extensively used to compensate the load current
harmonics and load unbalance at distribution level. This results in an additional hardware cost. However, in this
project it has incorporated the features of APF in the conventional inverter interfacing renewable with the grid,
without any additional hardware cost. Here, the main idea is the maximum utilization of inverter rating which is
most of the time underutilized due to intermittent nature of RES. The grid-interfacing inverter can effectively be
utilized to perform the four important functions they are to transfer active power harvested from the renewable
resources (wind, solar, etc.), load reactive power demand support, current harmonics compensation at PCC and
current unbalance and neutral current compensation in case of 3-phase 4-wire system. Moreover, with adequate
control of grid-interfacing inverter, all the four objectives can be accomplished either individually or
simultaneously. The PQ constraints at the PCC can therefore be strictly maintained within the utility standards
without additional hardware cost.
With such a control, the combination of grid-interfacing inverter and the 3-phase 4-wire linear/non-linear
unbalanced load at point of common coupling appears as balanced linear load to the grid. This new control
concept is demonstrated with extensive MATLAB/Simulink simulation studies
A CONTROL APPROACH FOR GRID INTERFACING INVERTER IN 3 PHASE 4 WIRE DISTRIBUT...IJMER
With the increase in load demand, the Renewable Energy Sources (RES) are
increasingly connected in the distribution systems which utilizes power electronic
Converters/Inverters. Nowadays, 3-phase 4-wire distribution power system has been widely used in
residential and office buildings, manufacturing facilities, schools etc This paper presents a novel
control strategy for achieving maximum benefits from the grid-interfacing inverters when installed in
3-phase 4-wire distribution systems. The inverter can thus be utilized as: 1) power converter to inject
power to the grid, and 2) shunt APF to compensate current unbalance, load current harmonics and
load neutral current. All of these functions may be accomplished either individually or
simultaneously. This new control concept is demonstrated with extensive MATLAB/Simulink
simulation studies
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
A Novel control of a Grid-Interfacing Inverter to Improve the Quality of Powe...IJERA Editor
Renewable energy resources (RES) are being increas- ingly connected in distribution systems utilizing power electronic converters. This paper presents a novel control strategy for achieving maximum benefits from these grid-interfacing inverters when installed in 3-phase 4-wire distribution systems. The inverter is controlled to perform as a multi-function device by incorporating active power filter functionality. The inverter can thus be utilized as: 1) power converter to inject power generated from RES to the grid, and 2) shunt APF to compensate current unbalance, load current harmonics, load reactive power demand and load neutral current. All of these functions may be accomplished either individually or simultaneously. With such a control, the combination of grid-interfacing inverter and the 3-phase 4-wire linear/non-linear unbalanced load at point of common coupling appears as balanced linear load to the grid. This new control concept is demonstrated with extensive MATLAB/Simulink simulation studies and validated through digital signal processor-based laboratory experimental results.
Power Quality Improvement of Grid Interconnection of renewable Energy Based D...IJERA Editor
This paper presents a grid interfacing inverter which compensates power quality problems and also interface Renewable Energy Sources with the help of electric grid. Renewable Energy Sources are being increasingly connected in distribution system utilizing power electronic converters. Grid interfacing inverter can be used: 1) To improve the transfer of active power harvested from RES; 2) To meet load reactive power demand support ; 3) To reduce current harmonics by incorporating the current harmonic compensator at point of common coupling(PCC) ; 4) current unbalance and neutral current compensation in case of 3-phase 4-wire system. The fuzzy logic can be used in many applications especially, when the process/models are complex to analyse by using classical methods. Mainly fuzzy logic controller is used to control DC capacitor voltage. Simulations are carried out using MATLAB/SIMULINK to verify the performance of the controller. The output shows the controller has fast dynamic response high accuracy of tracking DC voltage reference and robust to load parameters variations.
Research Inventy : International Journal of Engineering and Scienceresearchinventy
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
Improved Power Quality by using STATCOM Under Various Loading ConditionsIJMTST Journal
A Power quality problem is an occurrence manifested as a nonstandard voltage, current or frequency that
results in a failure or a mis-operation of end user equipment’s. Utility distribution networks, sensitive
industrial loads and critical commercial operations suffer from various types of outages and service
interruptions which can cost significant financial losses. With the restructuring of power systems and with
shifting trend towards distributed and dispersed generation, the issue of power quality is going to take
newer dimensions. Injection of the wind power into an electric grid affects the power quality. The
performance of the wind turbine and thereby power quality are determined on the basis of measurements
and the norms followed according to the guideline specified in International Electro-technical Commission
standard, IEC-61400. The influence of the wind turbine in the grid system concerning the power quality
measurements are-the active power, reactive power, variation of voltage, flicker, harmonics, and electrical
behavior of switching operation and these are measured according to national/international guidelines.
Static Compensator (STATCOM) is connected at a point of common coupling with a battery energy storage
system (BESS) to mitigate the power quality issues. The battery energy storage is integrated to sustain the
real power source under fluctuating wind power. Here two control schemes for STATCOM are Fuzzy logic
controller and hybrid Fuzzy logic controller. We can better response for hybrid fuzzy compare to fuzzy logic
controller. The STATCOM control scheme for the grid connected wind energy generation system for power
quality improvement is simulated using MATLAB/SIMULINK in power system block set. Finally the proposed
scheme is applied for both balanced and unbalanced linear nonlinear loads.
Distributed Generation Sources are becoming an inseparable part of modern electrical grids. Finding the control strategies which can help them to be as much as possibly beneficial for the grid has been a big concern among the researchers. In this work, a PQ controller for connecting A DC source simulates the effect of a Distributed Generation to the grid based on the decoupling of Active and Reactive powers has been proposed. The Simulation results which have been in the MATLAB/Simulink environment show the effectiveness of this control technique for injecting the defined value of active and reactive power to the grid.
Improvement of Power Quality using Fuzzy Logic Controller in Grid Connected P...IAES-IJPEDS
In this paper, the design of combined operation of UPQC and PV-ARRAY is designed. The proposed system is composed of series and shunt inverters connected back to back by a dc-link to which pv-array is connected. This system is able to compensate voltage and current related problems both in inter-connected mode and islanding mode by injecting active power to grid. The fundamental aspect is that the power electronic devices (PE) and sensitive equipments (SE) are normally designed to work in non-polluted power system, so they would suffer from malfunctions when supply voltage is not pure sinusoidal. Thus this proposed operating strategy with flexible operation mode improves the power quality of the grid system combining photovoltaic array with a control of unified power quality conditioner. Pulse Width Modulation (PWM) is used in both three phase four leg inverters. A Proportional Integral (PI) and Fuzzy Logic Controllers are used for power quality improvement by reducing the distortions in the output power. The simulated results were compared among the two controller’s strategies With pi controller and fuzzy logic controller
Application of Unified Power Flow Controller in Nigeria Power System for Impr...ijtsrd
With the increased rate of urbanization and industrialization, the Nigerian electric power system is being put under pressure, high power losses which has led to fluctuation in voltage level. In this work the Nigeria 330Kv network of 42 bus system was considered. Data for the analysis were obtained from Transmission Company of Nigeria National Control Centre, Osogbo TCN and MATLAB PSAT software with newton Raphson's solution method embedded in it was used to carry out the analysis. The results of the analysis showed that many of the bus voltages were outside the voltage limits of ±5 i.e 0.95pu 1.05pu . After compensation with Flexible AC Transmission System devices FACTs namely Unified Power Flow Controller UPFC which can be used to control power flow on a transmission line, the voltage profile almost flat with bus voltages within acceptable voltage limits. It is also evident that the UPFC is device that can used to combat the voltage problem in the Nigerian electric power system. Adikaibe James | Prof. Engr. F. O. Enemuoh | Aghara Jachimma "Application of Unified Power Flow Controller in Nigeria Power System for Improvement of Voltage Profile" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd27838.pdfPaper URL: https://www.ijtsrd.com/engineering/electrical-engineering/27838/application-of-unified-power-flow-controller-in-nigeria-power-system-for-improvement-of-voltage-profile/adikaibe-james
Advance Technology in Application of Four Leg Inverters to UPQCIJPEDS-IAES
This article presents a novel application of four leg inverter with
conventional Sinusoidal Pulse Width Modulation (SPWM) Scheme to
Unified Power Quality Conditioner (UPQC). The Power Quality problem
became burning issues since the starting of high voltage AC transmission
system. Hence, in this article it has been discussed to mitigate the PQ issues
in high voltage AC systems through a three phase Unified Power Quality
Conditioner (UPQC) under various conditions, such as harmonic mitigation
scheme, non linear loads, sag and swell conditions as well. Also, it proposes
to control harmoincs with various artificial intelligent techniques. Thus
application of these control technique such as Neural Networks (ANN)
Fuzzy Logic makes the system performance in par with the standards
and also compared with existing system. The simulation results based on
MATLAB/Simulink are discussed in detail to support the concept developed
in the paper.
Power-Quality Improvement Features In Grid Interconnection of Wind Energy Sou...AM Publications
The increased power demand, the depletion of the fossil fuel resources and the growth of the environmental pollution has led
the world to think seriously of other alternative sources of energy. So renewable energy resources (RES) are being connected to the
distribution systems, mostly done by using power electronic converters. A new control strategy for achieving maximum advantage from
these grid-interfacing inverters which are when installed in 3-phase 4-wire distribution systems is given in this paper. With the inverter
control, the inverter can be used as a multi-function device, which includes the function of: 1) power converter to inject power generated
from RES to the grid, and 2) shunt APF to compensate current unbalance, load current harmonics, load reactive power demand and
load neutral current. These functions of the inverter can be done either individually or simultaneously. The proposed inverter with the
control when connected, helps the 3-phase 4-wire linear/non-linear unbalanced load at point of common coupling appear as balanced
linear load to the grid. With MATLAB/Simulink simulation studies, the proposed control technique is demonstrated and evaluated here.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
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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.
Comparison of PI and ANN Control Techniques for Nine Switches UPQC to Improve...MABUSUBANI SHAIK
Abstract: This paper presents a comprehensive review on the UPQC to reinforce power quality. Typically this can be often speculated to gift a broad outline on the varied possible intelligent controls used with UPQC. The most purpose of a UPQC is to control on voltage flicker/unbalance, reactive power and harmonics. In different words, the UPQC has the potential of up power quality at the purpose of installation on power industrial power systems. The appliance of computing is growing quick within the
space of power electronics and drives. From olden days to now days we are using twelve switches used in back to back configuration. But now we are using nine switches instead of 12 switches. In 9 switch UPQC converters given the most useful benefits compared to 12 switches power converter. The nine switches UPQC converter gets the best results by using of two methods. They are one is PI controller technique and other one is ANN controller technique. By contrast PI and ANN, ANN is better than PI for power quality enhancement and voltage sag and voltage swell mitigations. The factitious neural network
(ANN) is taken into account as a replacement tool to style management electronic equipment for power-quality (PQ) devices. A whole simulation study is administrated to analysis the performance of the ANN controller and compares its performance with the quality PI controller results. The nine-switch convertor has already been proved to possess sure benefits, additionally to its part saving topological feature. Despite these benefits, the nine-switch convertor has thus far found restricted applications because of its several perceived performance tradeoffs like requiring associate degree outsized dc-link capacitance, restricted amplitude sharing, and unnatural part shift between its 2 sets of output terminals. Rather than acceptive these tradeoffs as limitations, a nine-switch power conditioner is projected here that nearly ―converts‖ most of those topological short comings into
fascinating performance benefits. Aiming more to cut back its switch losses, Harmonics, Voltage Sag & Swell associate degree acceptable discontinuous modulation theme is projected and studied here thoroughly to doubly make sure that top reduction of commutations is achieved. With associate degree suitably designed management theme with PI and ANN with physical
phenomenon controller then incorporated, the nine-switch convertor is shown to favorably raise the general power quality in Simulation, thus justifying its role as an influence conditioner at a reduced value.
Keywords: ANN, Active Power Filters, PI Controller, Nine Switch Converter, Power Quality, UPQC.
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.
SIMULATION OF REDUCED SWITCH INVERTER BASED UPQC WITH FUZZY LOGIC AND ANN CON...MABUSUBANI SHAIK
ABSTRACT
This paper presents a new methodology to reduce harmonic distortion in UPQC using artificial neural network
and fuzzy logic controller. So this paper main aim is improve power quality by using UPQC with ANN and FLC. The most purpose of the proposed (ANN & FLC) is capable of providing good static and dynamic performances compared to PI controller. The UPQC is to control on voltage flicker/unbalance, reactive power and harmonics. In different words, the UPQC has the potential of up power quality at the purpose of installation on power industrial power systems. The appliance of computing is growing quick within the space of power electronics and drives. From olden days to now days we are using twelve switches used in back to back configuration. But now we are using nine switches instead of 12
switches. In 9 switch UPQC converter given the most useful benefits compared to 12 switches power converter. The nine switches UPQC converter gets the best results by using of three methods. They are one is PI controller technique, ANN controller technique and FLC controller technique. By contrast PI, FLC and ANN, ANN is better than (FLC & PI) for power quality enhancement and voltage sag and voltage swell mitigations. The factitious neural network (ANN) is taken into account as a replacement tool to style management electronic equipment for power quality (PQ) devices. A whole
simulation study is administrated to analysis the performance of the ANN controller and compares its performance with the quality FLC & PI controller’s results. The nine-switch convertor has already been proved to possess sure benefits,
additionally to its part saving topological feature. Despite these benefits, the nine-switch convertor has thus far found restricted applications because of its several perceived performance tradeoffs like requiring associate degree outsized
dc-link capacitance, restricted amplitude sharing, and unnatural part shift between its 2 sets of output terminals. Rather than acceptive these tradeoffs as limitations, a nine-switch power conditioner is projected here that nearly “converts” most of those topological short comings into fascinating performance benefits. Aiming more to cut back its switch losses,
Harmonics, Voltage Sag & Swell associate degree acceptable discontinuous modulation theme is projected and studied here thoroughly to doubly make sure that top reduction of commutations is achieved. With associate degree suitably
designed management theme with PI and ANN with Fuzzy logic controller then incorporated, the nine-switch convertor is shown to favorably raise the general power quality in Simulation, thus justifying its role as an influence conditioner at a reduced value.
KEYWORDS: ANN, Active Power Filters, PI Controller, Nine Switch Converter, Power Quality, UPQC
A fault-tolerant photovoltaic integrated shunt active power filter with a 27-...IJECEIAES
This paper introduces a fault-tolerant shunt active power filter (SAPF). The novility in of this work is that it poposes a solutions to increase the reliability of shunt active power filter to maintain its operation under a single-phase open-circuit fault in the SAPF. This will increase the reliability of the whole power system. The SAPF is composed of a 4-leg 27-level inverter based on asymmetric cascaded H-bridge topology. If an open-circuit fault is introduced to the operation of the SAPF, a special control technique will be implemented and the redundant leg of the SAPF will be activated. The faulttolerant SAPF can do many tasks under healthy operating conditions and post and open circuit fault depending on the state of charge (SOC) of the batteries. It can mitigate harmonics in the power system, improve power factor in the system by injecting reactive power, and inject real power to the system. The proposed SAPF is tested and simulated in MATLAB/Simulink and the results have shown a significant improvement in total harmonics distortion (THD) of the source current from 13.9% to 3.9% under the normal operating condition and from 42% to 8.4% post and open circuit fault.
A NOVEL CONTROL STRATEGY FOR POWER QUALITY IMPROVEMENT USING ANN TECHNIQUE FO...IJERD Editor
The proposed system presents power-control strategies of a Micro grid-connected hybrid generation
system with versatile power transfer. This hybrid system allows maximum utilization of freely available
renewable energy sources like wind and photovoltaic energies. For this, an adaptive MPPT algorithm along with
standard perturbs and observes method will be used for the system.
The inverter converts the DC output from non-conventional energy into useful AC power for the
connected load. This hybrid system operates under normal conditions which include normal room temperature
in the case of solar energy and normal wind speed at plain area in the case of wind energy. However, designing
an optimal micro grid is not an easy task, due to the fact that primary energy carriers are changeable and
uncontrollable, as is the demand. Traditional design and optimization tools, developed for controlled power
sources, cannot be employed here. Simulation methods seem to be the best solution.
The dynamic model of the proposed system is first elaborated in the stationary reference frame and
then transformed into the synchronous orthogonal reference frame. The transformed variables are used in
control of the voltage source converter as the heart of the interfacing system between DG resources and utility
grid. By setting an appropriate compensation current references from the sensed load currents in control circuit
loop of DG, the active, reactive, and harmonic load current components will be compensated with fast dynamic
response, thereby achieving sinusoidal grid currents in phase with load voltages, while required power of the
load is more than the maximum injected power of the DG to the grid. In addition, the proposed control method
of this paper does not need a phase-locked loop in control circuit and has fast dynamic response in providing
active and reactive power components of the grid-connected loads.
Grid Interconnection of Renewable Energy Sources at the Distribution Level Wi...Pradeep Avanigadda
Renewable energy resources (RES) are being increasingly connected in distribution systems utilizing power electronic converters.
This project presents a novel control strategy for achieving maximum benefits from these grid-interfacing inverters when installed in 3-phase 4-wire distribution systems.
The inverter can thus be utilized as:
1) power converter to inject power generated from RES to the grid &
2) shunt APF to compensate current unbalance, load current harmonics, load reactive power demand and load neutral current.
Artificial neural network based unity power factor corrector for single phas...IJECEIAES
Due to the negative effects of the non-linear semiconductor devices and the passive electrical components (inductor and capacitor) in the converter circuits, and that are deteriorating the power factor (PF) and total harmonics distortion (THD) of grid current, this study proposes a novel unity PF correction controller based on a new algorithm of neural network to improve the performance of a single phase boost DC-DC converter with respect to the mentioned concerns. The controller guarantees stable load voltage. The PF corrector, firstly measures the phase shift between grid voltage and grid current waveforms, then through a new artificial neural network (ANN) algorithm, a suitable duty cycle is predicted to guide and control the converter to reduce the phase shift between grid voltage and grid current as possible to have maximum PF which is unity PF, and to improve the THD level of grid current. The proposed system is simulated and evaluated via Simulink of MATLAB, the simulation results are collected at constant duty cycle and at controlled duty cycle through the proposed PF controller using different loads. The presented PF controller guarantees the unity power factor, and enhances the grid alternating current THD.
Research Inventy : International Journal of Engineering and Scienceresearchinventy
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
Improved Power Quality by using STATCOM Under Various Loading ConditionsIJMTST Journal
A Power quality problem is an occurrence manifested as a nonstandard voltage, current or frequency that
results in a failure or a mis-operation of end user equipment’s. Utility distribution networks, sensitive
industrial loads and critical commercial operations suffer from various types of outages and service
interruptions which can cost significant financial losses. With the restructuring of power systems and with
shifting trend towards distributed and dispersed generation, the issue of power quality is going to take
newer dimensions. Injection of the wind power into an electric grid affects the power quality. The
performance of the wind turbine and thereby power quality are determined on the basis of measurements
and the norms followed according to the guideline specified in International Electro-technical Commission
standard, IEC-61400. The influence of the wind turbine in the grid system concerning the power quality
measurements are-the active power, reactive power, variation of voltage, flicker, harmonics, and electrical
behavior of switching operation and these are measured according to national/international guidelines.
Static Compensator (STATCOM) is connected at a point of common coupling with a battery energy storage
system (BESS) to mitigate the power quality issues. The battery energy storage is integrated to sustain the
real power source under fluctuating wind power. Here two control schemes for STATCOM are Fuzzy logic
controller and hybrid Fuzzy logic controller. We can better response for hybrid fuzzy compare to fuzzy logic
controller. The STATCOM control scheme for the grid connected wind energy generation system for power
quality improvement is simulated using MATLAB/SIMULINK in power system block set. Finally the proposed
scheme is applied for both balanced and unbalanced linear nonlinear loads.
Distributed Generation Sources are becoming an inseparable part of modern electrical grids. Finding the control strategies which can help them to be as much as possibly beneficial for the grid has been a big concern among the researchers. In this work, a PQ controller for connecting A DC source simulates the effect of a Distributed Generation to the grid based on the decoupling of Active and Reactive powers has been proposed. The Simulation results which have been in the MATLAB/Simulink environment show the effectiveness of this control technique for injecting the defined value of active and reactive power to the grid.
Improvement of Power Quality using Fuzzy Logic Controller in Grid Connected P...IAES-IJPEDS
In this paper, the design of combined operation of UPQC and PV-ARRAY is designed. The proposed system is composed of series and shunt inverters connected back to back by a dc-link to which pv-array is connected. This system is able to compensate voltage and current related problems both in inter-connected mode and islanding mode by injecting active power to grid. The fundamental aspect is that the power electronic devices (PE) and sensitive equipments (SE) are normally designed to work in non-polluted power system, so they would suffer from malfunctions when supply voltage is not pure sinusoidal. Thus this proposed operating strategy with flexible operation mode improves the power quality of the grid system combining photovoltaic array with a control of unified power quality conditioner. Pulse Width Modulation (PWM) is used in both three phase four leg inverters. A Proportional Integral (PI) and Fuzzy Logic Controllers are used for power quality improvement by reducing the distortions in the output power. The simulated results were compared among the two controller’s strategies With pi controller and fuzzy logic controller
Application of Unified Power Flow Controller in Nigeria Power System for Impr...ijtsrd
With the increased rate of urbanization and industrialization, the Nigerian electric power system is being put under pressure, high power losses which has led to fluctuation in voltage level. In this work the Nigeria 330Kv network of 42 bus system was considered. Data for the analysis were obtained from Transmission Company of Nigeria National Control Centre, Osogbo TCN and MATLAB PSAT software with newton Raphson's solution method embedded in it was used to carry out the analysis. The results of the analysis showed that many of the bus voltages were outside the voltage limits of ±5 i.e 0.95pu 1.05pu . After compensation with Flexible AC Transmission System devices FACTs namely Unified Power Flow Controller UPFC which can be used to control power flow on a transmission line, the voltage profile almost flat with bus voltages within acceptable voltage limits. It is also evident that the UPFC is device that can used to combat the voltage problem in the Nigerian electric power system. Adikaibe James | Prof. Engr. F. O. Enemuoh | Aghara Jachimma "Application of Unified Power Flow Controller in Nigeria Power System for Improvement of Voltage Profile" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd27838.pdfPaper URL: https://www.ijtsrd.com/engineering/electrical-engineering/27838/application-of-unified-power-flow-controller-in-nigeria-power-system-for-improvement-of-voltage-profile/adikaibe-james
Advance Technology in Application of Four Leg Inverters to UPQCIJPEDS-IAES
This article presents a novel application of four leg inverter with
conventional Sinusoidal Pulse Width Modulation (SPWM) Scheme to
Unified Power Quality Conditioner (UPQC). The Power Quality problem
became burning issues since the starting of high voltage AC transmission
system. Hence, in this article it has been discussed to mitigate the PQ issues
in high voltage AC systems through a three phase Unified Power Quality
Conditioner (UPQC) under various conditions, such as harmonic mitigation
scheme, non linear loads, sag and swell conditions as well. Also, it proposes
to control harmoincs with various artificial intelligent techniques. Thus
application of these control technique such as Neural Networks (ANN)
Fuzzy Logic makes the system performance in par with the standards
and also compared with existing system. The simulation results based on
MATLAB/Simulink are discussed in detail to support the concept developed
in the paper.
Power-Quality Improvement Features In Grid Interconnection of Wind Energy Sou...AM Publications
The increased power demand, the depletion of the fossil fuel resources and the growth of the environmental pollution has led
the world to think seriously of other alternative sources of energy. So renewable energy resources (RES) are being connected to the
distribution systems, mostly done by using power electronic converters. A new control strategy for achieving maximum advantage from
these grid-interfacing inverters which are when installed in 3-phase 4-wire distribution systems is given in this paper. With the inverter
control, the inverter can be used as a multi-function device, which includes the function of: 1) power converter to inject power generated
from RES to the grid, and 2) shunt APF to compensate current unbalance, load current harmonics, load reactive power demand and
load neutral current. These functions of the inverter can be done either individually or simultaneously. The proposed inverter with the
control when connected, helps the 3-phase 4-wire linear/non-linear unbalanced load at point of common coupling appear as balanced
linear load to the grid. With MATLAB/Simulink simulation studies, the proposed control technique is demonstrated and evaluated here.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
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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.
Comparison of PI and ANN Control Techniques for Nine Switches UPQC to Improve...MABUSUBANI SHAIK
Abstract: This paper presents a comprehensive review on the UPQC to reinforce power quality. Typically this can be often speculated to gift a broad outline on the varied possible intelligent controls used with UPQC. The most purpose of a UPQC is to control on voltage flicker/unbalance, reactive power and harmonics. In different words, the UPQC has the potential of up power quality at the purpose of installation on power industrial power systems. The appliance of computing is growing quick within the
space of power electronics and drives. From olden days to now days we are using twelve switches used in back to back configuration. But now we are using nine switches instead of 12 switches. In 9 switch UPQC converters given the most useful benefits compared to 12 switches power converter. The nine switches UPQC converter gets the best results by using of two methods. They are one is PI controller technique and other one is ANN controller technique. By contrast PI and ANN, ANN is better than PI for power quality enhancement and voltage sag and voltage swell mitigations. The factitious neural network
(ANN) is taken into account as a replacement tool to style management electronic equipment for power-quality (PQ) devices. A whole simulation study is administrated to analysis the performance of the ANN controller and compares its performance with the quality PI controller results. The nine-switch convertor has already been proved to possess sure benefits, additionally to its part saving topological feature. Despite these benefits, the nine-switch convertor has thus far found restricted applications because of its several perceived performance tradeoffs like requiring associate degree outsized dc-link capacitance, restricted amplitude sharing, and unnatural part shift between its 2 sets of output terminals. Rather than acceptive these tradeoffs as limitations, a nine-switch power conditioner is projected here that nearly ―converts‖ most of those topological short comings into
fascinating performance benefits. Aiming more to cut back its switch losses, Harmonics, Voltage Sag & Swell associate degree acceptable discontinuous modulation theme is projected and studied here thoroughly to doubly make sure that top reduction of commutations is achieved. With associate degree suitably designed management theme with PI and ANN with physical
phenomenon controller then incorporated, the nine-switch convertor is shown to favorably raise the general power quality in Simulation, thus justifying its role as an influence conditioner at a reduced value.
Keywords: ANN, Active Power Filters, PI Controller, Nine Switch Converter, Power Quality, UPQC.
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.
SIMULATION OF REDUCED SWITCH INVERTER BASED UPQC WITH FUZZY LOGIC AND ANN CON...MABUSUBANI SHAIK
ABSTRACT
This paper presents a new methodology to reduce harmonic distortion in UPQC using artificial neural network
and fuzzy logic controller. So this paper main aim is improve power quality by using UPQC with ANN and FLC. The most purpose of the proposed (ANN & FLC) is capable of providing good static and dynamic performances compared to PI controller. The UPQC is to control on voltage flicker/unbalance, reactive power and harmonics. In different words, the UPQC has the potential of up power quality at the purpose of installation on power industrial power systems. The appliance of computing is growing quick within the space of power electronics and drives. From olden days to now days we are using twelve switches used in back to back configuration. But now we are using nine switches instead of 12
switches. In 9 switch UPQC converter given the most useful benefits compared to 12 switches power converter. The nine switches UPQC converter gets the best results by using of three methods. They are one is PI controller technique, ANN controller technique and FLC controller technique. By contrast PI, FLC and ANN, ANN is better than (FLC & PI) for power quality enhancement and voltage sag and voltage swell mitigations. The factitious neural network (ANN) is taken into account as a replacement tool to style management electronic equipment for power quality (PQ) devices. A whole
simulation study is administrated to analysis the performance of the ANN controller and compares its performance with the quality FLC & PI controller’s results. The nine-switch convertor has already been proved to possess sure benefits,
additionally to its part saving topological feature. Despite these benefits, the nine-switch convertor has thus far found restricted applications because of its several perceived performance tradeoffs like requiring associate degree outsized
dc-link capacitance, restricted amplitude sharing, and unnatural part shift between its 2 sets of output terminals. Rather than acceptive these tradeoffs as limitations, a nine-switch power conditioner is projected here that nearly “converts” most of those topological short comings into fascinating performance benefits. Aiming more to cut back its switch losses,
Harmonics, Voltage Sag & Swell associate degree acceptable discontinuous modulation theme is projected and studied here thoroughly to doubly make sure that top reduction of commutations is achieved. With associate degree suitably
designed management theme with PI and ANN with Fuzzy logic controller then incorporated, the nine-switch convertor is shown to favorably raise the general power quality in Simulation, thus justifying its role as an influence conditioner at a reduced value.
KEYWORDS: ANN, Active Power Filters, PI Controller, Nine Switch Converter, Power Quality, UPQC
A fault-tolerant photovoltaic integrated shunt active power filter with a 27-...IJECEIAES
This paper introduces a fault-tolerant shunt active power filter (SAPF). The novility in of this work is that it poposes a solutions to increase the reliability of shunt active power filter to maintain its operation under a single-phase open-circuit fault in the SAPF. This will increase the reliability of the whole power system. The SAPF is composed of a 4-leg 27-level inverter based on asymmetric cascaded H-bridge topology. If an open-circuit fault is introduced to the operation of the SAPF, a special control technique will be implemented and the redundant leg of the SAPF will be activated. The faulttolerant SAPF can do many tasks under healthy operating conditions and post and open circuit fault depending on the state of charge (SOC) of the batteries. It can mitigate harmonics in the power system, improve power factor in the system by injecting reactive power, and inject real power to the system. The proposed SAPF is tested and simulated in MATLAB/Simulink and the results have shown a significant improvement in total harmonics distortion (THD) of the source current from 13.9% to 3.9% under the normal operating condition and from 42% to 8.4% post and open circuit fault.
A NOVEL CONTROL STRATEGY FOR POWER QUALITY IMPROVEMENT USING ANN TECHNIQUE FO...IJERD Editor
The proposed system presents power-control strategies of a Micro grid-connected hybrid generation
system with versatile power transfer. This hybrid system allows maximum utilization of freely available
renewable energy sources like wind and photovoltaic energies. For this, an adaptive MPPT algorithm along with
standard perturbs and observes method will be used for the system.
The inverter converts the DC output from non-conventional energy into useful AC power for the
connected load. This hybrid system operates under normal conditions which include normal room temperature
in the case of solar energy and normal wind speed at plain area in the case of wind energy. However, designing
an optimal micro grid is not an easy task, due to the fact that primary energy carriers are changeable and
uncontrollable, as is the demand. Traditional design and optimization tools, developed for controlled power
sources, cannot be employed here. Simulation methods seem to be the best solution.
The dynamic model of the proposed system is first elaborated in the stationary reference frame and
then transformed into the synchronous orthogonal reference frame. The transformed variables are used in
control of the voltage source converter as the heart of the interfacing system between DG resources and utility
grid. By setting an appropriate compensation current references from the sensed load currents in control circuit
loop of DG, the active, reactive, and harmonic load current components will be compensated with fast dynamic
response, thereby achieving sinusoidal grid currents in phase with load voltages, while required power of the
load is more than the maximum injected power of the DG to the grid. In addition, the proposed control method
of this paper does not need a phase-locked loop in control circuit and has fast dynamic response in providing
active and reactive power components of the grid-connected loads.
Grid Interconnection of Renewable Energy Sources at the Distribution Level Wi...Pradeep Avanigadda
Renewable energy resources (RES) are being increasingly connected in distribution systems utilizing power electronic converters.
This project presents a novel control strategy for achieving maximum benefits from these grid-interfacing inverters when installed in 3-phase 4-wire distribution systems.
The inverter can thus be utilized as:
1) power converter to inject power generated from RES to the grid &
2) shunt APF to compensate current unbalance, load current harmonics, load reactive power demand and load neutral current.
Artificial neural network based unity power factor corrector for single phas...IJECEIAES
Due to the negative effects of the non-linear semiconductor devices and the passive electrical components (inductor and capacitor) in the converter circuits, and that are deteriorating the power factor (PF) and total harmonics distortion (THD) of grid current, this study proposes a novel unity PF correction controller based on a new algorithm of neural network to improve the performance of a single phase boost DC-DC converter with respect to the mentioned concerns. The controller guarantees stable load voltage. The PF corrector, firstly measures the phase shift between grid voltage and grid current waveforms, then through a new artificial neural network (ANN) algorithm, a suitable duty cycle is predicted to guide and control the converter to reduce the phase shift between grid voltage and grid current as possible to have maximum PF which is unity PF, and to improve the THD level of grid current. The proposed system is simulated and evaluated via Simulink of MATLAB, the simulation results are collected at constant duty cycle and at controlled duty cycle through the proposed PF controller using different loads. The presented PF controller guarantees the unity power factor, and enhances the grid alternating current THD.
Design of Low Cost Stair Climbing Robot Using ArduinoIJERA Editor
Since the invention of the wheel, Man has sought to reduce effort to get things done easily. Ultimately, it has resulted in the invention of the Robot, an Engineering Marvel. Up until now, the biggest factor that hampers wide proliferation of robots is locomotion and maneuverability. They are not dynamic enough to conform even to the most commonplace terrain such as stairs. To overcome this, we are proposing a stair climbing robot that looks a lot like the human leg and can adjust itself according to the height of the step. But, we are currently developing a unit to carry payload of about 4 Kg. The automatic adjustment in the robot according to the height of the stair is done by connecting an Android device that has an application programmed in OpenCV with an Arduino in Host mode. The Android Device uses it camera to calculate the height of the stair and sends it to the Arduino for further calculation. This design employs an Arduino Mega ADK 2560 board to control the robot and other home fabricated custom PCB to interface it with the Arduino Board. The bot is powered by Li-Ion batteries and Servo motors.
Comparative Analysis of the Effects of Cashew and Mango Extracts on the Rheol...IJERA Editor
Comparative analysis of the effects of cashew and mango extracts on the rheological properties of water based mud is presented. To control corrosion of drilling materials, corrosion inhibitor is usually used as one of the drilling mud additives. Such inhibitive substance can only be applied when it improves the rheological properties of the drilling mud. In this work, the mud samples were formulated in the absence and presence of various concentrations of cashew and mango extracts. The production method of the mud and the determination of its rheological and allied properties were carried out based on the mud production standards of American Petroleum Institute. From the analysis of the experimental results, cashew and mango leaves extracts are suitable additives for the production of water based mud. Mango leaves extract shows higher improvement of the rheological properties of the drilling mud. Use of plant leaves extracts as drilling mud additives will encourage local content development.
Research on License Plate Recognition and Extraction from complicated ImagesIJERA Editor
Vehicle number plate recognition has attracted many researchers for intelligent transportation systems such as the payment of parking fee, controlling the traffic volume, traffic data collection, etc. We are presenting an enhanced license plate extraction methodology which includes edge statistics and the morphology. The proposed methodology includes vertical edge extraction, background curve and noise removing, edge statistical analysis and morphology-based license plate extraction.
Il mio intervento del 15/11/2014 a BdiBlogger, l'evento organizzato per creare un punto d'incontro tra aziende e blogger.
Nell'intervento analizzo quali sono stati i fattori determinanti adottati dal mio blog - quello che si può definire un CEO Blog - quale base per il piano marketing della la mia azienda.
Holly Dorning, Research Analyst at the Nuffield Trust, explores whether we can measure quality of care for Allied Health Professionals, as part of her presentation to the QualityWatch conference on Allied Health Professionals.
Defluoridization Using a Natural Adsorbent, Strychnos PotatorumIJERA Editor
The study assessed the suitability of low-cost natural adsorbent to effectively remediate fluoride contaminated water. The removal of fluoride from aqueous solution by using Strychnos Potatorum was studied in batch technique. Influence of pH, adsorbent dose, contact time, co ions, speed and initial concentration on the adsorption were investigated. The maximum removal of fluoride ion was obtained at pH 7. The removal of fluoride was expressed with Langmuir and Freundlich isotherm. It was found that the sufficient time for adsorption equilibrium of fluoride ion was 1 hour. The removal of fluoride ions was maximum for the adsorbent dosage of SP is 50mg/50ml. The fluoride adsorption was maximum at 60minutes. The adsorption of F- ion was maximum in the shaking speed of 120 rpm. The presence of interfering ions such as nitrate and carbonate showed positive effect while sulphate and chloride showed little negative effect and phosphate showed high negative effect for the adsorbent. The optimum initial fluoride concentration for SP adsorbent was 1mg/50ml.
EU Budget Finland 2014-2020 update November 2014Joost Holleman
EU Budget Finland 2014-2020 update November 2014
The five European Structural and Investment Funds;
| The European Regional Development Fund
| The European Social Fund
| The Cohesion Fund
| The European Maritime and Fisheries Fund
| The European Agricultural Fund for Rural Development
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
A Novel Technique for Enhancing Active and Reactive Power Quality for Renewab...IJMER
Renewable energy resources (RES) are being increasingly connected in distribution systems utilizing power electronic converters. This paper presents a novel control strategy for achieving maximum benefits from these grid-interfacing inverters when installed in 3-phase 4-wire distribution systems. The inverter is controlled to perform as a multi-function device by incorporating active power filter functionality. The inverter can thus be utilized as: 1) power converter to inject power generated from RES to the grid, and 2) shunt APF to compensate current unbalance, load current harmonics, load reactive power demand and load neutral current. All of these functions may be accomplished either individually or simultaneously. With such a control, the combination of grid-interfacing inverter and the 3-phase 4-wire linear/non-linear unbalanced load at point of common coupling appears as balanced linear load to the grid. This new control concept is demonstrated with extensive MATLAB/Simulink simulation studies and results.
Grid Interconnection of Renewable Energy Sources at the Distribution Level Wi...Pradeep Avanigadda
Renewable energy resources (RES) are being increasingly
connected in distribution systems utilizing power electronic
converters. This paper presents a novel control strategy for
achieving maximum benefits from these grid-interfacing inverters
when installed in 3-phase 4-wire distribution systems. The inverter
is controlled to perform as a multi-function device by incorporating
active power filter functionality. The inverter can thus be
utilized as: 1) power converter to inject power generated from
RES to the grid, and 2) shunt APF to compensate current unbalance,
load current harmonics, load reactive power demand and
load neutral current. All of these functions may be accomplished
either individually or simultaneously. With such a control, the
combination of grid-interfacing inverter and the 3-phase 4-wire
linear/non-linear unbalanced load at point of common coupling
appears as balanced linear load to the grid. This new control
concept is demonstrated with extensive MATLAB/Simulink simulation
studies and validated through digital signal processor-based
laboratory experimental results.
Index Terms—Active power filter
A Technique for Shunt Active Filter meld micro grid SystemIJERA Editor
The proposed system presents a control technique for a micro grid connected hybrid generation system ith case study interfaced with a three phase shunt active filter to suppress the current harmonics and reactive power present in the load using PQ Theory with ANN controller. This Hybrid Micro Grid is developed using freely renewable energy resources like Solar Photovoltaic (SPV) and Wind Energy (WE). To extract the maximum available power from PV panels and wind turbines, Maximum power point Tracker (MPPT) has been included. This MPPT uses the “Standard Perturbs and Observe” technique. By using PQ Theory with ANN Controller, the Reference currents are generated which are to be injected by Shunt active power filter (SAPF)to compensate the current harmonics in the non linear load. Simulation studies shows that the proposed control technique performs non-linear load current harmonic compensation maintaining the load current in phase with the source voltage.
Grid Connected PV System with Power Quality Improvement Using Intelligent Con...IJMTST Journal
The depletion of the fossil fuel resources and the global warming effects has led the world to think
seriously of other alternative sources of energy. So renewable energy resources (RES) are being connected to
the distribution systems, mostly done by using power electronic converters. But use of power electronic
converters and non-linear loads like at distribution level injects harmonics, which intern cause power quality
problems. Distribution static compensator (DSTATCOM) is very popular in compensating power problems for
nonlinear and unbalanced loads. Any change in the load affects the DC-link voltage (DCLV) directly.
Conventionally, a PI controller is used to maintain the DCLV to the reference value, but its transient response
is poor. So, fuzzy logic controller is proposed which shows better dynamic response. To trigger inverter HCC
is used. The proposed inverter with the control when connected to wind energy, helps the 3-phase 4-wire
linear/non-linear unbalanced load at point of common coupling appear as balanced linear load to the grid.
With MATLAB/Simulink simulation studies, the proposed control technique is demonstrated and evaluated
here.
This paper deals with controlling a grid-connected dual-active bridge multilevel inverter for renewable energy integration. The concept of direct power control is integrated with model predictive control algorithm, which is termed as predictive direct power control, to control the real and reactive power injected into the power grid. The proposed multilevel inverter allows more options of feasible voltage vectors for switching vector selections in order to generate multilevel outputs, and thereby obtaining high power quality in the power grid. By using the predictive direct power control, simulation results show that the proposed multilevel inverter produces lower power ripple and manage to achieve currents with low total harmonic distortion which are well within the IEEE standard. The modeling and simulation of the system are implemented and validated by MATLAB Simulink software.
1.compensation of reactive power using d statcom in grid interfaced pv systemEditorJST
This paper displays the upgrade of voltage droops, Harmonic mutilation and low power figure utilizing Distribution Static Compensator (D-STATCOM) with LCL Passive Filter in Distribution Framework. At whatever point there is an entrance of photovoltaic cell energy to the low voltage appropriated matrix, there happen the issue of confuse in voltage and recurrence in the system, maybe brought on by non-direct loads, creating music. The model depends on the Voltage Source Converter (VSC) guideline. The D-STATCOM infuses a current into the framework to alleviate the voltage lists. LCL Passive Filter Was then added to D-STATCOM to enhance symphonies bending and low power figure. The reproductions were performed utilizing MATLAB SIMULINK.
Application of PI controller based active filter for harmonic mitigation of g...journalBEEI
The recent trends show the interconnection of PV system with electric grid. With this configuration the issue of harmonics comes into existence. The mounting figure of power-electronic instruments has formed considerable impression on the power-quality of electric supply. Harmonics deformations have conventionally been handled amid the application of passive-LC filters. Active Filter has emerged as a good substitute for passive filters to reduce the harmonics to great extent as it has numerous benefits over the former filters. The active filter’s most vital part is the applied control strategies. Several researches are being under process to advance the functioning of the filter. One of the important control requirements of filter is the regulation of DC link up capacitor voltage. Here the voltage supervision of capacitor is being done using PI controller. The paper show current harmonics compensation of PV grid connected system using PI controller based active filter. Simulation outcomes have been shown which displays the harmonics are within the IEEE boundaries.
REDUCING SOURCE CURRENT HARMONICS DUE TO BALANCED AND UN-BALANCED VOLTAGE VAR...IJCI JOURNAL
Electricity demand has been increasing due to the increase of population and industries. Hence it is very
important to feed the demand with quality of generation. Improvement of power quality is the greater
concern in advanced power system element, it is essential to congregate the need of energy by employ the
renewable energy generating sources like pv, fuel cell, biomass, wind, etc and utilizing many more
applications like grid interconnected systems, power quality improvement. The situations like harmonic,
reactive power exchanging, power factor correction, balanced and un-balanced voltage variations & so on,
due to greater effect on highly susceptible loads are to be encouraged in power distribution system. To
enhance these circumstances, custom power appliances are used to achieve high grid voltage stability. In
this paper, a voltage distortions controlled D-STATCOM based on fuzzy controller is a meticulous power
appliance for enhancing harmonic distortions from high power semiconductor switching device,
exchanging the both active & reactive power, defend the gird stability by implementing DG technology, to
regulate the power quality issues in power distribution network. This paper implements the comparative
analysis of PI and Fuzzy controlled DSTATCOM with energy backup scheme, controlled by pwm control
technique and founded that fuzzy based IPQ theory for generation of reference current signals improves the
power quality than PI based IPQ theory and this analysis is dynamically evaluated with Matlab/Simulink.
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A photovoltaic integrated unified power quality conditioner with a 27-level i...TELKOMNIKA JOURNAL
This paper presents a Unified Power Quality Conditioner (UPQC) with a 27-level inverter based on
an asymmetric H-bridge topology. Each phase of the inverter is composed of three H-bridges, supplied by
three DC sources scaled in the power of three. The output of the multilevel inverter is connected directly to
the point of common coupling (PCC) without the need to a transformer or a filter. The calculation of the Shunt
Active Power Filter (SAPF) compensation current is based on the generalized theory of synchronous frame
(d-q theory) while the calculation of a series active filter voltage is based on Instantaneous Reactive Power
(p-q theory). The control of the SAPF is achieved by using a closed-loop vector control followed by a new
multilevel modulation technique. In addition to the capability of harmonic elimination of both current and
voltage drawn from the source, the UPQC can produce real and reactive power to feed the loads during
prolonged voltage outages or source shortage. Batteries pack are used as a dc link, which is charged from
photovoltaic array connected to the battery through a maximum power point tracker and charge controller.
The injection of real and reactive power depends on the state of charge (SOC) of batteries, the frequency of
the system, real and reactive power of the load, and power factor at the point of PCC. The proposed UPQC
strategy is simulated in MATLAB SIMULINK and the results have shown a significant improved in Total
Harmonics Distortion (THD) of both the voltage and currents.
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.
Comparative Study of Three Phase Grid Connected Photovoltaic Inverter Using P...IJPEDS-IAES
A comparative study of three phase grid connected photovoltaic (PV)
inverter using Proportional-Integral (PI) controller and Fuzzy logic controller
(FLC) is presented in this paper. Proposed three phase inverter with single DC
source employing three phase transformer for grid connected PV system
controlled by using space vector pulse width modulation (SVPWM) technique.
PI and FLC are used as current controller for regulating the current. Perturb and
observe maximum power point technique (MPPT) is used for tracking of
maximum power from the PV panel. Finally total harmonic distortion (THD)
comparison made between two controllers for validation of results.
Furthermore swithing losses of inverter are also presented. The simulation
results are obtained using MATLAB simulink.
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
4.power quality improvement in dg system using shunt active filterEditorJST
Injection of power generated by the wind turbine system into an electric grid mainly effects the power quality. The performance of this wind turbine and its power quality is determined on the basis of its measurement of power ratings as per IEEE standards. The influence of the wind turbine in the grid system concerning the power quality measurements are the active power, reactive power, variation of voltage, flicker, harmonics, and electrical behavior of switching operation. To mitigate the power quality problems this paper proposes the shunt compensator techniques. Here, the proposed system is verified experimentally using both STATCOM and TSC compensators. This control schemes for grid connected wind energy system is simulated using Matlab/Simulink.
Improving Distribution Feeders for Photovoltaic Generation by Loop Power Cont...IJMER
Now a day’s solar power plants are more reliable, because no fuel and reduced CO2 emission. But the solar power generation system do not work in all weather conditions, it is power generated only solar radiation time .To overcome this problem by using (pv)). In fuel cell power generation there will be no problems, where as in fuel cell power distribution systems have some problems like overloading the distribution feeders. In this project to overcome this overloading by using Loop Power Controller (LPC).The loop power controller to control real power and reactive power flow by adjusting voltage ratio and phase shift. Daily loading unbalance is determined by analyzing (pv) power generation recording by using SCADA system and load profile based on Data Automation System (DAS).The loop power controller can improve controllability, operational flexibility and reduce power loss of the distribution system. The Loop Power Controller (LPC) is based on the MATLAB/ SIMULINK.
Similar to Enhancement in Power Quality With Grid Interconnection of Renewable Energy Sources at Distribution Level (20)
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
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This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
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Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Enhancement in Power Quality With Grid Interconnection of Renewable Energy Sources at Distribution Level
1. B.Yella Reddy Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 4, Issue 10( Part - 4), October 2014, pp.19-24
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Enhancement in Power Quality With Grid Interconnection of
Renewable Energy Sources at Distribution Level
B.Yella Reddy1
M.Pratap Naik2
1P.G. Student, Electrical & Electronics Engineering Department, Newton’s Institute of Engineering, Macherla,
A.P, India
2Assistant Professor, Electrical & Electronics Engineering Department, Newton’s Institute of Engineering
Macherla, A.P, India
ABSTRACT
At present the Renewable energy resources (RES) are being increasingly connected in distribution systems
utilizing power electronic converters. This paper presents a novel control strategy for achieving maximum
benefits from these grid-interfacing inverters when installed in 3-phase 4-wire distribution systems. The inverter
is controlled to perform as a multi-function device by incorporating active power filter functionality. The
inverter can thus be utilized as power converter to inject power generated from RES to the grid and shunt APF
to compensate current unbalance, load current harmonics, load reactive power demand and load neutral current.
All of these functions may be accomplished either individually or simultaneously. With such a control, the
combination of grid-interfacing inverter and the 3-phase 4-wire linear/non-linear unbalanced load at point of
common coupling appears as balanced linear load to the grid. This new control concept is demonstrated with
extensive MATLAB/Simulink simulation studies and validated through digital signal processor-based
laboratory experimental results.
Key Words- Active power filters (APF), distributed generation (DG), distribution system, grid interconnection,
power quality (PQ), and renewable energy.
I. INTRODUCTION
Electric utilities and end users of electric power
are becoming increasingly concerned about meeting
the growing energy demand. Seventy five percent of
total global energy demand is supplied by the burning
of fossil fuels. But increasing air pollution, global
warming concerns, diminishing fossil fuels and their
increasing cost have made it necessary to look
towards renewable sources as a future energy
solution. Since the past decade, there has been an
enormous interest in many countries on renewable
energy for power generation. The market
liberalization and government’s incentives have
further accelerated the renewable energy sector
growth. Renewable energy source (RES) integrated at
distribution level is termed as distributed generation
(DG). The utility is concerned due to the high
penetration level of intermittent RES in distribution
systems as it may pose a threat to network in terms of
stability, voltage regulation and power-quality (PQ)
issues. Therefore, the DG systems are required to
comply with strict technical and regulatory
frameworks to ensure safe, reliable and efficient
operation of overall network. With the advancement
in power electronics and digital control technology,
the DG systems can now be actively controlled to
enhance the system operation with improved PQ at
PCC. However, the extensive use of power
electronics based equipment and non-linear loads at
PCC generate harmonic currents, which may
deteriorate the quality of power.
Generally, current controlled voltage source
inverters are used to interface the intermittent RES in
distributed system. Recently, a few control strategies
for grid connected inverters incorporating PQ
solution have been proposed. In an inverter operates
as active inductor at a certain frequency to absorb the
harmonic current. But the exact calculation of
network inductance in real-time is difficult and may
deteriorate the control performance. A similar
approach in which a shunt active filter acts as active
conductance to damp out the harmonics in
distribution network is proposed. A control strategy
for renewable interfacing inverter based on – theory
is proposed. In this strategy both load and inverter
current sensing is required to compensate the load
current harmonics.
The non-linear load current harmonics may
result in voltage harmonics and can create a serious
PQ problem in the power system network. Active
power filters (APF) are extensively used to
compensate the load current harmonics and load
unbalance at distribution level. This results in an
RESEARCH ARTICLE OPEN ACCESS
2. B.Yella Reddy Int. Journal of Engineering Research and Applications www.ijera.com
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additional hardware cost. However, in this paper
authors have incorporated the features of APF in the,
conventional inverter interfacing renewable with the
grid, without any additional hardware cost. Here, the
main idea is the maximum utilization of inverter
rating which is most of the time underutilized due to
intermittent nature of RES. It is shown in this paper
that the grid-interfacing inverter can effectively be
utilized to perform following important functions: 1)
transfer of active power harvested from the
renewable resources (wind, solar, etc.); 2) load
reactive power demand support; 3) current harmonics
compensation at PCC; and 4) current unbalance and
neutral current compensation in case of 3-phase 4-
wire system. Moreover, with adequate control of
grid-interfacing inverter, all the four objectives can
be accomplished either individually or
simultaneously. The PQ constraints at the PCC can
therefore be strictly maintained within the utility
standards without additional hardware cost.
The paper is organized as follows. Section II,
deal with the system description. In section III,
simulation results are presented and finally Section
IV concludes the paper.
II. SYSTEM DESCRIPTION
The given system consists of RES connected to
the dc-link of a grid-interfacing inverter as shown in
Fig 1. The voltage source inverter is a key element of
a DG system as it interfaces the renewable energy
source to the grid and delivers the generated power.
The RES may be a DC source or an AC source with
rectifier coupled to dc-link. Usually, the fuel cell and
photovoltaic energy sources generate power at
variable low dc voltage, while the variable speed
wind turbines generate power at variable ac voltage.
Thus, the power generated from these renewable
sources needs power conditioning (i.e., dc/dc or
ac/dc) before connecting on dc-link. The dc-capacitor
decouples the RES from grid and also allows
independent control of converters on either side of
dc-link.
1. DC-Link Voltage and Power Control Operation
Due to the intermittent nature of RES, the
generated power is of variable nature. The dc-link
plays an important role in transferring this variable
power from renewable energy source to the grid. RES
are represented as current sources connected to the
dc-link of a grid-interfacing inverter. Fig. 2 shows the
systematic
representation of power transfer from the renewable
energy resources to the grid via the dc-link. The
current injected by renewable into dc-link at voltage
level Vdc can be given as
(1)
where is PRES the power generated from RES.
Fig.2.DC-Link equivalent diagram.
The current flow on the other side of dc-link can be
represented as,
(2)
where Pinv, PG and PLOSS are total power available at
grid-interfacing inverter side, active power supplied
to the grid and inverter losses, respectively. If
inverter losses are negligible then PRES=PG.
2. Control of Grid Interfacing Inverter
The control diagram of grid- interfacing inverter
for a 3-phase 4-wire system is shown in Fig. 3. The
fourth leg of inverter is used to compensate the
neutral current of load. The main aim of proposed
approach is to regulate the power at PCC during:
1)PRES=0; 2) PRES< total load power(PL); and 3) PRES>
total load power(PL).
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Fig.1. Schematic of proposed renewable based distributed generation system.
Fig.3. Block diagram representation of grid-interfacing inverter control.
While performing the power management
operation, the inverter is actively controlled in such a
way that it always draws/ supplies fundamental active
power from/ to the grid. If the load connected to the
PCC is non-linear or unbalanced or the combination
of both, the given control approach also compensates
the harmonics, unbalance, and neutral current. The
duty ratio of inverter switches are varied in a power
cycle such that the combination of load and inverter
injected power appears as balanced resistive load to
the grid. The regulation of dc-link voltage carries the
information regarding the exchange of active power
in between renewable source and grid. Thus the
output of dc-link voltage regulator results in an active
current (Im). The multiplication of active current
component (Im) with unity grid voltage vector
templates (Ua, Ub and Uc) generates the reference grid
currents ( , ). The reference grid neutral
current ( ) is set to zero, being the instantaneous
sum of balanced grid currents. The grid
synchronizing angle (θ) obtained from phase locked
loop (PLL) is used to generate unity vector template
as
(3)
(4)
(5)
The actual dc-link voltage (Vdc) is sensed and passed
through a first-order low pass filter (LPF) to
eliminate the presence of switching ripples on the dc-
link voltage and in the generated reference current
signals. The difference of this filtered dc-link voltage
and reference dc-link voltage (Vdc
*
) is given to a
discrete- PI regulator to maintain a constant dc-link
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voltage under varying generation and load conditions.
The dc-link voltage error (Vdcerr (n)) at nth
sampling
instant is given as:
(6)
The output of discrete-PI regulator at nth
sampling
instant is expressed as
(7)
where KPVdc=10 and KIVdc=0.05 are proportional and
integral gains of dc-voltage regulator. The
instantaneous values of reference three phase grid
currents are computed as
(8)
(9)
(10)
The neutral current, present if any, due to the
loads connected to the neutral conductor should be
compensated by forth leg of grid-interfacing inverter
and thus should not be drawn from the grid. In other
words, the reference current for the grid neutral
current is considered as zero and can be expressed as
(11)
The reference grid currents (Ia
*
,Ib
*
,Ic
*
and In
*
)are
compared with actual grid currents (Ia
*
, Ib
*
,Ic
*
and
In
*
) to compute the current errors as
(12)
(13)
(14)
(15)
These current errors are given to hysteresis
current controller. The hysteresis controller then
generates the switching pulses (P1 to Pg ) for the gate
drives of grid-interfacing inverter. The average model
of 4-leg inverter can be obtained by the following
state space equations
(16)
(17)
(18)
(19)
(20)
Where VInva, VInvb, VInvc and VInvn are the three-phase
ac switching voltages generated on the output
terminal of inverter. These inverter output voltages
can be modeled in terms of instantaneous dc bus
voltage and switching pulses of the inverter as
(21)
(22)
(23)
(24)
Similarly the charging currents, IInvad, IInvbd, IInvcd and
IInvnd on dc bus due to the each leg of inverter can be
expressed as
(25)
(26)
(27)
(28)
The switching pattern of each IGBT inside inverter
can be formulated On the basis of error between
actual and reference current of inverter, which can be
explained as:
If , then upper switch S1
will be OFF (P1=0) and lower switch will be ON
(P4=1) in the phase “a” leg of inverter. If
, then upper switch will be
ON (P1=1) and lower switch S4 will be OFF (P4=1) in
the phase “a” leg of inverter.
Where hb is the width of hysteresis band. On the
same principle, the switching pulses for the other
remaining three legs can be derived.
Initially the grid interfacing inverter is not
connected to the network (i.e the load power demand
is totally supplied by the grid alone). Therefore,
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before time t=0.72sec, the grid current profile is
identical to the load current profile. At t=0.72 sec, the
grid interfacing inverter is connected to the network.
At this instant the inverter starts injecting the current
in such a way that the profile of grid current starts
changing from unbalanced non linear to balanced
sinusoidal current. As the inverter also supplies the
load neutral current demand, the grid neutral current
becomes zero after t=0.72 sec.
At t=0.72sec, the inverter starts injecting active
power generated from RES(Pres=Pinv).since the
generated power is more than the load power demand
the additional power is fed back to the grid. The
negative sign of Pgrid, after time 0.72 sec suggests that
the grid is now receiving power from RES.
Moreover, the grid interfacing inverter also supplies
the load reactive power demand locally. Thus once
the inverter is in operation the grid only
supplies/receives fundamental active power.
At t=0.82 sec, the active power from RES is
increased to evaluate the performance of system
under variable power generation from RES. This
results in increased magnitude of inverter current. As
the load power demand is considered as constant, this
additional power generated from RES flows towards
grid, which can be noticed from the increased
magnitude of grid current as indicated by its profile.
At t=0.92 sec the power available from RES is
reduced. The corresponding change in the inverter
and grid currents are shown in fig. The active and
reactive power flows between the inverter, load and
grid during increase and decrease of energy
generation from RES shown in fig. the dc-link
voltage across the grid interfacing inverter during
different operating condition is maintained at
constant level in order to facilitate the active and
reactive power flow.
III. SIMULATION RESULTS
In order to verify the proposed control approach
to achieve multi-objectives for grid interfaced DG
systems connected to a 3-phase 4-wire network, an
extensive simulation study is carried out using
MATLAB/Simulink. A 4-leg current controlled
voltage source inverter is actively controlled to
achieve balanced sinusoidal grid currents at unity
power factor (UPF) despite of highly unbalanced
nonlinear load at PCC under varying renewable
generating conditions. A RES with variable output
power is connected on the dc-link of grid-interfacing
inverter. An unbalanced 3-phase 4-wire nonlinear
load, whose unbalance, harmonics, and reactive
power need to be compensated, is connected on PCC.
The fig 4., indicates the simulink model of proposed
system.
Fig 4. simulink modal of proposed system.
The waveforms of grid voltages (Va, Vb, Vc), grid
currents (Ia, Ib, Ic, In), unbalanced load current (I1a, I1b,
I1c, I1n) and inverter currents (Iinva, Iinvb, Iinvc, Iinvn) are
shown in fig. 5.
Fig. 5. Simulation results: y-axis - (a) Grid voltages,
(b) Grid Currents (c) Unbalanced load currents,
(d) Inverter Currents, x-axis-time in sec.
The corresponding active-reactive powers of grid
(Pgrid, Qgrid), load (Pload, Qload), and inverter (Pinv, Qinv)
are shown in fig. 6.
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Fig.6. Simulation results: y-axis- (a) PQ-Grid, (b) PQ
-Load, (c) PQ-Inverter, (d) dc-link voltage, x-axis
time sec.
From the simulation results it is known that the
grid interfacing inverter can be effectively used to
compensate the load reactive power, current
unbalance and current harmonics in addition to active
power injection from RES. This enables the grid to
supply/receive sinusoidal and balanced power at
UPF.
IV. CONCLUSION
This paper has presented a novel control of an
existing grid interfacing inverter to improve the
quality of power at PCC for a 3-phase 4-
wireDGsystem. It has been shown that the grid-
interfacing inverter can be effectively utilized for
power conditioning without affecting its normal
operation of real power transfer. The grid-interfacing
inverter with the proposed approach can be utilized
to:
i) Inject real power generated from RES to the grid,
and/or,
ii) Operate as a shunt Active Power Filter (APF).
This approach thus eliminates the need for additional
power conditioning equipment to improve the quality
of power at PCC. Extensive MATLAB/Simulink
simulation results have validated the proposed
approach and have shown that the grid-interfacing
inverter can be utilized as a multi-function device.
It is further demonstrated that the PQ
enhancement can be achieved under three different
scenarios: 1) PRES=0, 2) PRES < PLoad, and 3) PRES >
PLoad. The current unbalance, current harmonics and
load reactive power, due to unbalanced and non-
linear load connected to the PCC, are compensated
effectively such that the grid side currents are always
maintained as balanced and sinusoidal at unity power
factor. Moreover, the load neutral current is prevented
from flowing into the grid side by compensating it
locally from the fourth leg of inverter. When the
power generated from RES is more than the total load
power demand, the grid-interfacing inverter with the
proposed control approach not only fulfills the total
load active and reactive power demand (with
harmonic compensation) but also delivers the excess
generated sinusoidal active power to the grid at unity
power factor.
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