This paper proposes an improvement of the direct power control (DPC) scheme of a grid connected three phase voltage source inverter based on artificial neural networks (ANN) and fuzzy logic (FL) techniques for the renewable energy applications. This advanced control strategy is based on two intelligent operations, the first one is the replacement of the conventional switching table of a three phase voltage source inverter (VSI) by a selector based on artificial neural networks approach, and the second one is the replacement of the hysteresis comparators by fuzzy logic controllers for the instantaneous active and reactive power errors. These operations enable to reduce the power ripples, the harmonic disturbances and increase the response time period of the system. Finally, the simulation results were obtained by Matlab/Simulink environment, under a unity power factor (UPF). These results verify the transient performances, the validity and the efficiency of the proposed DPC scheme.
In a distributed generation system, divers renewable agents are connected to the low voltage 3 phase utility grid by an inverter which is used as power condition and must assurance the higher efficiency of the renewable agent. To achieve this level of efficiency, a unitary power factor between the utility grid voltages and the inverter currents is necessary, and a synchronization algorithm is required for the perfect synchronization between the 3-phase utility grid and the renewable agent. The aim of this paper is to present the optimization of the performance of a Synchronization controller for a 3-phase photovoltaic grid-connected system, assessing its accuracy under different conditions and studying their drawbacks and advantages. A grid connected photovoltaic system with a nominal power of 5 kW is used so as to assess the behavior of the synchronization algorithm when the 3 phase utility grid is affected by some disturbances such as voltage unbalances.
Control of Two Stage PV Power System under the Unbalanced Three Phase Grid Vo...ijtsrd
This paper proposes a dynamic power decoupling DPD strategy for the three phase grid tied PV power system without increasing the dc link capacitance. Under normal condition, the interleaved boost converter will extract the maximum power point MPP from the PV array and the three phase inverter will inject the power to the grid. During the unbalanced grid fault scenario, the input power and current of the interleaved boost converter will be controlled by the proposed DPD to achieve the power decoupling capability as well as to eliminate the dc link voltage oscillation. The proposed work has been carried out in MATLAB, and the results are presented. Manasa | Nirmaladevi ""Control of Two Stage PV Power System under the Unbalanced Three-Phase Grid Voltages"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-2 , February 2020,
URL: https://www.ijtsrd.com/papers/ijtsrd30091.pdf
Paper Url : https://www.ijtsrd.com/engineering/electrical-engineering/30091/control-of-two-stage-pv-power-system-under-the-unbalanced-three-phase-grid-voltages/manasa
This work includes the establishment of a Photovoltaic system connected to the grid by means of an inverter. The fundamental goal of the work is to incorporate an advanced active power flow management scheme in order to adopt load at any weather condition along with the advantage of maximum active power flow and zero harmonics from PV inverter to the grid. The outcome of analysis and control design of grid connected PV inverter using a Proportional-Integral (PI) control technique is based on synchronous dq rotating reference frame so as to achieve maximum output voltage and record the active power. It has been observed that the model provides a better rate of stability as compared to the existing topology.
An inverter system applied with the PV source typically has a problem of lower input voltage due to constraint in the PV strings connection. As a countermeasure a DC-DC boost converter is placed in between to achieve a higher voltage at the inverter DC link for connection to the grid and to realize the MPPT operation. This additional stage contributes to losses and complexity in control thus reducing the overall system efficiency. This work discussed on the design and development of a grid-connected quasi-Z-source PV inverter which has different topology and control method compared to the conventional voltage source inverter and able to overcome the above disadvantages. Modelling and performance analysis of the voltage and current controller to achieve a good power transfer from the PV source, as well sycnchronization with the grid are presented in detail. Results from both simulation and experimental verification demonstrate the designed and developed grid-connected qZSI PV inverter works successfully equivalent to the conventional voltage source inverter system.
The emerging of inductive wireless power transfer (IWPT) technology provides more opportunities for the electric vehicle (EV) battery to have a better recharging process. With the development of IWPT technology, various way of wireless charging of the EV battery is proposed in order to find the best solution. To further understand the fundamentals of the IWPT system itself, an ample review is done. There are different ways of EV charging which are static charging (wired), static wireless charging (SWC) and dynamic wireless charging (DWC). The review starts with a brief comparison of static charging, SWC and DWC. Then, in detailed discussion on the fundamental concepts, related laws and equations that govern the IWPT principle are also included. In this review, the focus is more on the DWC with a little discussion on static charging and SWC to ensure in-depth understanding before one can do further research about the EV charging process. The in-depth perception regarding the development of DWC is elaborated together with the system architecture of the IWPT and DWC system and the different track versions of DWC, which is installable to the road lane.
Alternating current (AC) electrical drives mainly require smaller current (or torque) ripples and lower total harmonic distortion (THD) of voltage for excellent drive performances. Normally, in practice, to achieve these requirements, the inverter needs to be operated at high switching frequency. By operating at high switching frequency, the size of filter can be reduced. However, the inverter which oftenly employs insulated gate bipolar transistor (IGBT) for high power applications cannot be operated at high switching frequency. This is because, the IGBT switching frequency cannot be operated above 50 kHz due to its thermal restrictions. This paper proposes an alternate switching strategy to enable the use of IGBT for operating the inverter at high switching frequency to improve THD performances. In this strategy, each IGBT in a group of switches in the modified inverter circuit will operate the switching frequency at one-fourth of the inverter switching frequency. The alternate switching is implemented using simple analog and digital integrated circuits.
Environmental factors such as air pollution and increase in global warming by using polluting fuels are the most important reasons of using renewable and clean energy that runs in global community. Wind energy is one of the most suitable and widely used kind of renewable energy which had been in consideration so well. This paper introduces an electric power generation
system of wind based on Y-source and improved Y-source inverter to deliver optimal electrical power to the network. This new converter is from impedance source converters family. This presented converter has more degrees of freedom to adjust voltage gain and modulation. Also, by limiting the range of simultaneous control (shooting through) while it maintains the
highest power of maximizer, it can operate in higher modulation range. This causes the reduce of stress in switching and thus it will improve the quality of output. Recommended system had been simulated in MATLAB/Simulink and shown results indicate accurate functionality.
In a distributed generation system, divers renewable agents are connected to the low voltage 3 phase utility grid by an inverter which is used as power condition and must assurance the higher efficiency of the renewable agent. To achieve this level of efficiency, a unitary power factor between the utility grid voltages and the inverter currents is necessary, and a synchronization algorithm is required for the perfect synchronization between the 3-phase utility grid and the renewable agent. The aim of this paper is to present the optimization of the performance of a Synchronization controller for a 3-phase photovoltaic grid-connected system, assessing its accuracy under different conditions and studying their drawbacks and advantages. A grid connected photovoltaic system with a nominal power of 5 kW is used so as to assess the behavior of the synchronization algorithm when the 3 phase utility grid is affected by some disturbances such as voltage unbalances.
Control of Two Stage PV Power System under the Unbalanced Three Phase Grid Vo...ijtsrd
This paper proposes a dynamic power decoupling DPD strategy for the three phase grid tied PV power system without increasing the dc link capacitance. Under normal condition, the interleaved boost converter will extract the maximum power point MPP from the PV array and the three phase inverter will inject the power to the grid. During the unbalanced grid fault scenario, the input power and current of the interleaved boost converter will be controlled by the proposed DPD to achieve the power decoupling capability as well as to eliminate the dc link voltage oscillation. The proposed work has been carried out in MATLAB, and the results are presented. Manasa | Nirmaladevi ""Control of Two Stage PV Power System under the Unbalanced Three-Phase Grid Voltages"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-2 , February 2020,
URL: https://www.ijtsrd.com/papers/ijtsrd30091.pdf
Paper Url : https://www.ijtsrd.com/engineering/electrical-engineering/30091/control-of-two-stage-pv-power-system-under-the-unbalanced-three-phase-grid-voltages/manasa
This work includes the establishment of a Photovoltaic system connected to the grid by means of an inverter. The fundamental goal of the work is to incorporate an advanced active power flow management scheme in order to adopt load at any weather condition along with the advantage of maximum active power flow and zero harmonics from PV inverter to the grid. The outcome of analysis and control design of grid connected PV inverter using a Proportional-Integral (PI) control technique is based on synchronous dq rotating reference frame so as to achieve maximum output voltage and record the active power. It has been observed that the model provides a better rate of stability as compared to the existing topology.
An inverter system applied with the PV source typically has a problem of lower input voltage due to constraint in the PV strings connection. As a countermeasure a DC-DC boost converter is placed in between to achieve a higher voltage at the inverter DC link for connection to the grid and to realize the MPPT operation. This additional stage contributes to losses and complexity in control thus reducing the overall system efficiency. This work discussed on the design and development of a grid-connected quasi-Z-source PV inverter which has different topology and control method compared to the conventional voltage source inverter and able to overcome the above disadvantages. Modelling and performance analysis of the voltage and current controller to achieve a good power transfer from the PV source, as well sycnchronization with the grid are presented in detail. Results from both simulation and experimental verification demonstrate the designed and developed grid-connected qZSI PV inverter works successfully equivalent to the conventional voltage source inverter system.
The emerging of inductive wireless power transfer (IWPT) technology provides more opportunities for the electric vehicle (EV) battery to have a better recharging process. With the development of IWPT technology, various way of wireless charging of the EV battery is proposed in order to find the best solution. To further understand the fundamentals of the IWPT system itself, an ample review is done. There are different ways of EV charging which are static charging (wired), static wireless charging (SWC) and dynamic wireless charging (DWC). The review starts with a brief comparison of static charging, SWC and DWC. Then, in detailed discussion on the fundamental concepts, related laws and equations that govern the IWPT principle are also included. In this review, the focus is more on the DWC with a little discussion on static charging and SWC to ensure in-depth understanding before one can do further research about the EV charging process. The in-depth perception regarding the development of DWC is elaborated together with the system architecture of the IWPT and DWC system and the different track versions of DWC, which is installable to the road lane.
Alternating current (AC) electrical drives mainly require smaller current (or torque) ripples and lower total harmonic distortion (THD) of voltage for excellent drive performances. Normally, in practice, to achieve these requirements, the inverter needs to be operated at high switching frequency. By operating at high switching frequency, the size of filter can be reduced. However, the inverter which oftenly employs insulated gate bipolar transistor (IGBT) for high power applications cannot be operated at high switching frequency. This is because, the IGBT switching frequency cannot be operated above 50 kHz due to its thermal restrictions. This paper proposes an alternate switching strategy to enable the use of IGBT for operating the inverter at high switching frequency to improve THD performances. In this strategy, each IGBT in a group of switches in the modified inverter circuit will operate the switching frequency at one-fourth of the inverter switching frequency. The alternate switching is implemented using simple analog and digital integrated circuits.
Environmental factors such as air pollution and increase in global warming by using polluting fuels are the most important reasons of using renewable and clean energy that runs in global community. Wind energy is one of the most suitable and widely used kind of renewable energy which had been in consideration so well. This paper introduces an electric power generation
system of wind based on Y-source and improved Y-source inverter to deliver optimal electrical power to the network. This new converter is from impedance source converters family. This presented converter has more degrees of freedom to adjust voltage gain and modulation. Also, by limiting the range of simultaneous control (shooting through) while it maintains the
highest power of maximizer, it can operate in higher modulation range. This causes the reduce of stress in switching and thus it will improve the quality of output. Recommended system had been simulated in MATLAB/Simulink and shown results indicate accurate functionality.
The growing demand for electricity and the increasing integration of clean energies into the electrical grids requires the multiplication and reinforcement of high-voltage direct current (HVDC) projects throughout the world and demonstrates the interest in this electricity transmission technology. The transmitting system of the voltage source converter-high-voltage direct current (VSC-HVDC) consists primarily of two converter stations that are connected by a dc cable. In this paper, a nonlinear control based on the backstepping approach is proposed to improve the dynamic performance of a VSC-HVDC transmission system, these transport systems are characterized by different complexities such as parametric uncertainties, coupled state variables, neglected dynamics, presents a very interesting research topic. Our contribution through adaptive control based on the backstepping approach allows regulating the direct current (DC) bus voltage and the active and reactive powers of the converter stations. Finally, the validity of the proposed control has been verified under various operating conditions by simulation in the MATLAB/Simulink environment.
This paper presents a novel shunt active power filter (SAPF). The power converter that is used in this SAPF is constructed from a four-leg asymmetric multi-level cascaded H-bridge (CHB) inverter that is fed from a photovoltaic source. A three-dimensional space vector modulation (3D-SVPWM) technique is adopted in this work. The multi-level inverter can generate 27-level output with harmonic content is almost zero. In addition to the capability to inject reactive power and mitigating the harmonics, the proposed SAPF has also, the ability to inject real power as it is fed from a PV source. Moreover, it has a fault-tolerant capability that makes the SAPF maintaining its operation under a loss of one leg of the multi-level inverter due to an open-circuit fault without any degradation in the performance. The proposed SAPF is designed and simulated in MATLAB SIMULINK using a single nonlinear load and the results have shown a significant reduction in total harmonics distortion (THD) of the source current under the normal operating condition and post a failure in one phase of the SAPF. Also, similar results are obtained when IEEE 15 bus network is used.
Power quality is a concern for utility and grid operators due to a large penetration of intermittent and stochastic renewable power generation sources. One of the major concerns, when designing and controlling grid-feeding photovoltaic (PV) inverters is meeting the grid requirements. International grid requirements demand low-voltage ride-through (LVRT) capability and maintaining grid functionality during fault conditions. This paper presents a comprehensive review for several control techniques to assure the LVRT capability of grid-feeding converters as well as discussing their respective advantages and limitations in detail. Areas for further research are identified afterwards. Finally, the conclusion gives a brief summary and critique of the findings.
Transmission lines react to an unexpected increase in power, and if these power changes are not controlled, some lines will become overloaded on certain routes. Flexible alternating current transmission system (FACTS) devices can change the voltage range and phase angle and thus control the power flow. This paper presents suitable mathematical modeling of FACTS
devices including static var compensator (SVC) as a parallel compensator and high voltage direct current (HVDC) bonding. A comprehensive modeling of SVC and HVDC bonding in the form of simultaneous applications for power flow is also performed, and the effects of compensations are compared. The comprehensive model obtained was implemented on the 5-bus test system in MATLAB software using the Newton-Raphson method, revealed that generators have to produce more power. Also, the addition of these devices stabilizes the voltage and controls active and reactive power in the network.
Modeling and simulation of three phases cascaded H-bridge grid-tied PV inverterjournalBEEI
In this paper a control scheme for three phase seven level cascaded H-bridge inverter for grid tied PV system is presented. As power generation from PV depends on varing environmental conditions, for extractraction of maximum power from PV array, fuzzy MPPT controller is incorporated with each PV array. It gives fast and accurate response. To maintain the grid current
sinusoidal under varying conditions, a digital PI controller scheme is adopted. A MATLAB/Simulink model is developed for this purpose and results are presented. At last THD analysis is carried out in order to validate the performance of the overall system. As discussed, with this control strategy the balanced grid current is obtained keeping THD values with in the specified range of IEEE-519 standard.
Single Phase PV Grid-Connected in Smart Household Energy System with Anticipa...IJPEDS-IAES
This paper proposes an algorithm of Smart household energy systems to anticipate fault conditions in power system grid. Single phase PV grid- connected in smart household energy system is a smart system that determines electrical supply conditions to the load in residential electrical system. The smart system is consisted of two voltage source, conventional electricity system from national electricity provider as preferred source and photovoltaic as the alternative source. In smart system, fault conditions can be anticipated by selecting the appropriate voltage sources to supply the load. The condition of smart system can be described in power flow regulation to the load by detection and identification of amplitude, phase angle, and frequency of the voltage source compared to the system reference. The system mechanism is based on detection of voltage source using static transfer switch (STS) with phase locked loop (PLL) as voltage detection algorithm which output is used to determine decision logic algorithm for switching conditions. The results show that conditions of smart power system flow can be obtained based on voltage source selection in decision logic when fault condition occurs.
A new bidirectional multilevel inverter topology with a high number of voltage levels with a very reduced number of power components is proposed in this paper. Only TEN power switches and four asymmetric DC voltage sources are used to generate 25 voltage levels in this new topology. The proposed multilevel converter is more suitable for e-mobility and photovoltaic applications where the overall energy source can be composed of a few units/associations of several basic source modules. Several benefits are provided by this new topology: Highly sinusoidal current and voltage waveforms, low Total Harmonic Distortion, very low switching losses, and minimum cost and size of the device. For optimum control of this 25-level voltage inverter, a special Modified Hybrid Modulation technique is performed. The proposed 25-level inverter is compared to various topologies published recently in terms of cost, the number of active power switches, clamped diodes, flying capacitors, DC floating capacitors, and the number of DC voltage sources. This comparison clearly shows that the proposed topology is cost-effective, compact, and very efficient. The effectiveness and the good performance of the proposed multilevel power converter (with and without PWM control) are verified and checked by computational simulations.
An Adaptive Neuro-Fuzzy Inference Distributed Power Flow Controller (DPFC) in...IAES-IJPEDS
A well-prepared abstract enables the reader to identify the basic content of a document quickly and accurately, to determine its relevance to their interests, and thus to decide whether to read the document in its entirety. The Abstract should be informative and completely self-explanatory, provide a clear statement of the problem, the proposed approach or solution, and point out major findings and conclusions. The Abstract should be 100 to 200 words in length. The abstract should be written in the past tense. Standard nomenclature should be used and abbreviations should be avoided. No literature should be cited. The keyword list provides the opportunity to add keywords, used by the indexing and abstracting services, in addition to those already present in the title. Judicious use of keywords may increase the ease with which interested parties can locate our article.
Direct current (DC) electronic load is a useful equipment for testing the electrical system. It can emulate various load at a high rating. The electronic load requires a power converter to operate and a linear regulator is a common option. Nonetheless, it is hard to control due to the temperature variation. This paper proposed a DC electronic load using the boost converter. The proposed electronic load operates in the continuous current mode and control using the integral controller. The electronic load using the boost converter is compared with the electronic load using the linear regulator. The results show that the boost converter able to operate as an electronic load with an error lower than 0.5% and response time lower than 13 ms.
The inverter is the principal part of the photovoltaic (PV) systems that assures the direct current/alternating current (DC/AC) conversion (PV array is connected directly to an inverter that converts the DC energy produced by the PV array into AC energy that is directly connected to the electric utility). In this paper, we present a simple method for detecting faults that occurred during the operation of the inverter. These types of faults or faults affect the efficiency and cost-effectiveness of the photovoltaic system, especially the inverter, which is the main component responsible for the conversion. Hence, we have shown first the faults obtained in the case of the short circuit. Second, the open circuit failure is studied. The results demonstrate the efficacy of the proposed method. Good monitoring and detection of faults in the inverter can increase the system's reliability and decrease the undesirable faults that appeared in the PV system. The system behavior is tested under variable parameters and conditions using MATLAB/Simulink.
The increase in power demand has compelled the power system utilities to use series capacitive compensation in long transmission lines.
A problem called sub synchronous resonance (SSR) occurs in long lines because of series compensation. In this paper a flexible a.c. transmission
system (FACTS) device is used along with a proposed controller to damp out the sub synchronous oscillations from the system. An IEEE second
bench mark model is used for investigating the SSR problem, where a three phase short circuit fault is applied on the compensated transmission
line for analysis. A Matlab/Simulink model is used to study the time domain analysis of the system. An improvement in damping is seen with the
use of FACTS device i.e. unified power flow controller (UPFC) which is controlled by a Neural network (NN) based proportional integral (PI)
controller
Impact of hybrid FACTS devices on the stability of the Kenyan power system IJECEIAES
Flexible alternating current transmission system (FACTS) devices are deployed for improving power system’s stability either singly or as a combination. This research investigates hybrid FACTS devices and studies their impact on voltage, small-signal and transient stability simultaneously under various system disturbances. The simulations were done using five FACTS devices-static var compensator (SVC), static synchronous compensator (STATCOM), static synchronous series compensators (SSSC), thyristor controlled series compensator (TCSC) and unified power flow controller (UPFC) in MATLAB’s power system analysis toolbox (PSAT). These five devices were grouped into ten pairs and tested on Kenya’s transmission network under specific contingencies: the loss of a major generating machine and/or transmission line. The UPFC-STATCOM pair performed the best in all the three aspects under study. The settling times were 3 seconds and 3.05 seconds respectively for voltage and rotor angle improvement on the loss of a major generator at normal operation. The same pair gave settling times of 2.11 seconds and 3.12 seconds for voltage and rotor angle stability improvement respectively on the loss of a major transmission line at 140% system loading. From the study, two novel techniques were developed: A performance-based ranking system and classification for FACTS devices.
HIGH EFFICIENT BRIDGELESS BOOST RECTIFIER FOR LOW VOLTAGE ENERGY HARVESTING A...IAEME Publication
A single phase ac-dc bridgeless boost rectifier for low voltage energy harvesting applications is proposed in this paper. The conventional bridge type boost converters for low voltage energy harvesting requires more components hence they suffer from high power loss and require more number of energy storage components like inductors and capacitors. Conventional converters can be modeled for boost operation or buck-boost operation alone. The proposed converter overcomes the above mentioned draw backs of conventional converter. Detailed analysis of proposed convertor is also presented under boost, buck-boost mode operations. The proposed converter operation is analyzed using MATLAB/SIMULINK environment both open loop and closed loop conditions.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
This paper presents a thorough control structure of the distributed generators inside the microgrid during both grid-connected and islanded operation modes. These control structures of the DGs voltage source inverters are implemented in synchronous reference frame (SRF) and controlled using linear PI controllers. By implementing the control structures, the desired real and reactive power can be efficiently transferred to the local loads and the utility load by the microgrid generating units. A modified droop control technique is introduced to facilitate the microgrid performance during both modes of operation. The active and reactive power sharing of the load demand between the utility grid and the microgrid can be performed by this drop control technique during the islanded mode. The system performance during intentional islanding event and utility load increase is investigated. The effectiveness of the offered control structures is confirmed through simulation results during both modes of operation.
Design and Analysis of Three Phase Inverter with Two Buck/Boost MPPTs for DC ...IJERA Editor
Anintegration and operation of a three-phase inverter with twobuck/boost maximum power point trackers
(MPPTs) for dc-distribution applications. In a dc-distribution system, a three phase inverter isrequired to control
the power flow between dc busand three phase ac grid, and to regulate the dc bus to a certainrange of voltages.
A droop regulation mechanism according to the inverter inductor current levels to reduce capacitor size, balance
power flow, and accommodate load variation is proposed. Since thephotovoltaic (PV) array voltage can vary
from 0 to 5000 V, especially with thin-film PV panels, the MPPT topology is formed with buck and boost
converters to operate at the dc-bus voltage around 4000 V, reducing the voltage stress of its followed inverter.
Additionally, the controller can online check the input configuration of the two MPPTs, equally distribute the
PV-array output current to the two MPPTs in parallel operation, and switch control laws to smooth out mode
transition. A comparison between the conventional boost MPPT and the proposed buck/boost MPPT integrated
with a PV inverter is also presented. Asingle-phase bidirectional inverter with two buck/boost maximum power
point trackers (MPPTs) by using the closed loop circuit. This project is workout bySimulink using mat lab.
Recently, LCL has become amongst the most attractive filter used for grid-connected flyback inverters. Nonetheless, the switching of power devices in the inverter configuration creates harmonics that affect the end application behavior and might shorten its lifetime. Furthermore, the resonance frequencies produced by the LCL network contribute to the system instability. This paper proposes a step-by-step guide to designing an LCL filter by considering several key aspects such as the resonance frequency and maximum current ripple. A single-phase grid-connected flyback microinverter with an LCL filter was designed then constructed in the MATLAB/Simulink environment. Several different parameter variations and damping solutions were used to analyze the performance of the circuit. The simulation result shows a promising total harmonic distortion (THD) value below 5% and harmonic suppression up to 14%.
The extensive use of non-linear loads in industry becomes increasingly a serious problem that affects the quality of energy delivered to customers. Therefore, the shunt active power filter (SAPF) has emerged as an important industrial tool to eliminate induced harmonic currents and compensating of reactive power. This paper proposes an improved control configuration for SAPF based on a modern technique called predictive direct power control (Predictive-DPC). The principle of this control is based on the direct regulation of the instantaneous active and reactive powers to guarantee a good energy quality on the grid side. For this purpose the appropriate average voltage vector which cancels power tracking errors is calculated by a simple predictive model at the bigining of each control period. This type of control includes various features such as the lack of look up table (LUTs) and closed current loops and the constant switching frequency is achieved through the use of PWM modulation. The results of the simulation process show a high performance in the steady and transient state function for predictive-DPC control that might be a reasonable alternative to conventional DPC in the field of active power filtering.
In this paper, a detail design and description of a predictive current control scheme are adopted for three-phase grid-connected two-level inverter and its application in wind energy conversion systems. Despite its advantages, the predictive current controller is very sensitive to parameter variations which could eventually affected on system stability. To solve this problem, an estimation technique proposed to identify the value of harmonic filter parameter based on Model reference adaptive system (MRAS). Lyapunov stability theory is selected to guarantee a robust adaptation and stable response over large system parameter variation. The simulation results shows the efficiency of the proposed techniques to improve the current tracking performance.
Power quality optimization using a novel backstepping control of a three-phas...IJECEIAES
A novel nonlinear backstepping controller based on direct current (DC) link voltage control is proposed in three-phase grid-connected solar photovoltaic (PV) systems to control the active and reactive power flow between the PV system and the grid with improved power quality in terms of pure sinusoidal current injection with lower total harmonic distortion (THD), as well as to ensure unity power factor, or to compensate for reactive power required by the load, i.e., the electrical grid. The output power of the PV array is supplied to the grid through a boost converter with maximum power point tracking (MPPT) control and an inverter. Simulation results of the proposed controller show good robustness under nominal conditions, parameter variations, and load disturbances, which presents the main advantage of this controller as compared to an existing controller. The performance of this work was evaluated using a MATLAB/Simulink environment.
The growing demand for electricity and the increasing integration of clean energies into the electrical grids requires the multiplication and reinforcement of high-voltage direct current (HVDC) projects throughout the world and demonstrates the interest in this electricity transmission technology. The transmitting system of the voltage source converter-high-voltage direct current (VSC-HVDC) consists primarily of two converter stations that are connected by a dc cable. In this paper, a nonlinear control based on the backstepping approach is proposed to improve the dynamic performance of a VSC-HVDC transmission system, these transport systems are characterized by different complexities such as parametric uncertainties, coupled state variables, neglected dynamics, presents a very interesting research topic. Our contribution through adaptive control based on the backstepping approach allows regulating the direct current (DC) bus voltage and the active and reactive powers of the converter stations. Finally, the validity of the proposed control has been verified under various operating conditions by simulation in the MATLAB/Simulink environment.
This paper presents a novel shunt active power filter (SAPF). The power converter that is used in this SAPF is constructed from a four-leg asymmetric multi-level cascaded H-bridge (CHB) inverter that is fed from a photovoltaic source. A three-dimensional space vector modulation (3D-SVPWM) technique is adopted in this work. The multi-level inverter can generate 27-level output with harmonic content is almost zero. In addition to the capability to inject reactive power and mitigating the harmonics, the proposed SAPF has also, the ability to inject real power as it is fed from a PV source. Moreover, it has a fault-tolerant capability that makes the SAPF maintaining its operation under a loss of one leg of the multi-level inverter due to an open-circuit fault without any degradation in the performance. The proposed SAPF is designed and simulated in MATLAB SIMULINK using a single nonlinear load and the results have shown a significant reduction in total harmonics distortion (THD) of the source current under the normal operating condition and post a failure in one phase of the SAPF. Also, similar results are obtained when IEEE 15 bus network is used.
Power quality is a concern for utility and grid operators due to a large penetration of intermittent and stochastic renewable power generation sources. One of the major concerns, when designing and controlling grid-feeding photovoltaic (PV) inverters is meeting the grid requirements. International grid requirements demand low-voltage ride-through (LVRT) capability and maintaining grid functionality during fault conditions. This paper presents a comprehensive review for several control techniques to assure the LVRT capability of grid-feeding converters as well as discussing their respective advantages and limitations in detail. Areas for further research are identified afterwards. Finally, the conclusion gives a brief summary and critique of the findings.
Transmission lines react to an unexpected increase in power, and if these power changes are not controlled, some lines will become overloaded on certain routes. Flexible alternating current transmission system (FACTS) devices can change the voltage range and phase angle and thus control the power flow. This paper presents suitable mathematical modeling of FACTS
devices including static var compensator (SVC) as a parallel compensator and high voltage direct current (HVDC) bonding. A comprehensive modeling of SVC and HVDC bonding in the form of simultaneous applications for power flow is also performed, and the effects of compensations are compared. The comprehensive model obtained was implemented on the 5-bus test system in MATLAB software using the Newton-Raphson method, revealed that generators have to produce more power. Also, the addition of these devices stabilizes the voltage and controls active and reactive power in the network.
Modeling and simulation of three phases cascaded H-bridge grid-tied PV inverterjournalBEEI
In this paper a control scheme for three phase seven level cascaded H-bridge inverter for grid tied PV system is presented. As power generation from PV depends on varing environmental conditions, for extractraction of maximum power from PV array, fuzzy MPPT controller is incorporated with each PV array. It gives fast and accurate response. To maintain the grid current
sinusoidal under varying conditions, a digital PI controller scheme is adopted. A MATLAB/Simulink model is developed for this purpose and results are presented. At last THD analysis is carried out in order to validate the performance of the overall system. As discussed, with this control strategy the balanced grid current is obtained keeping THD values with in the specified range of IEEE-519 standard.
Single Phase PV Grid-Connected in Smart Household Energy System with Anticipa...IJPEDS-IAES
This paper proposes an algorithm of Smart household energy systems to anticipate fault conditions in power system grid. Single phase PV grid- connected in smart household energy system is a smart system that determines electrical supply conditions to the load in residential electrical system. The smart system is consisted of two voltage source, conventional electricity system from national electricity provider as preferred source and photovoltaic as the alternative source. In smart system, fault conditions can be anticipated by selecting the appropriate voltage sources to supply the load. The condition of smart system can be described in power flow regulation to the load by detection and identification of amplitude, phase angle, and frequency of the voltage source compared to the system reference. The system mechanism is based on detection of voltage source using static transfer switch (STS) with phase locked loop (PLL) as voltage detection algorithm which output is used to determine decision logic algorithm for switching conditions. The results show that conditions of smart power system flow can be obtained based on voltage source selection in decision logic when fault condition occurs.
A new bidirectional multilevel inverter topology with a high number of voltage levels with a very reduced number of power components is proposed in this paper. Only TEN power switches and four asymmetric DC voltage sources are used to generate 25 voltage levels in this new topology. The proposed multilevel converter is more suitable for e-mobility and photovoltaic applications where the overall energy source can be composed of a few units/associations of several basic source modules. Several benefits are provided by this new topology: Highly sinusoidal current and voltage waveforms, low Total Harmonic Distortion, very low switching losses, and minimum cost and size of the device. For optimum control of this 25-level voltage inverter, a special Modified Hybrid Modulation technique is performed. The proposed 25-level inverter is compared to various topologies published recently in terms of cost, the number of active power switches, clamped diodes, flying capacitors, DC floating capacitors, and the number of DC voltage sources. This comparison clearly shows that the proposed topology is cost-effective, compact, and very efficient. The effectiveness and the good performance of the proposed multilevel power converter (with and without PWM control) are verified and checked by computational simulations.
An Adaptive Neuro-Fuzzy Inference Distributed Power Flow Controller (DPFC) in...IAES-IJPEDS
A well-prepared abstract enables the reader to identify the basic content of a document quickly and accurately, to determine its relevance to their interests, and thus to decide whether to read the document in its entirety. The Abstract should be informative and completely self-explanatory, provide a clear statement of the problem, the proposed approach or solution, and point out major findings and conclusions. The Abstract should be 100 to 200 words in length. The abstract should be written in the past tense. Standard nomenclature should be used and abbreviations should be avoided. No literature should be cited. The keyword list provides the opportunity to add keywords, used by the indexing and abstracting services, in addition to those already present in the title. Judicious use of keywords may increase the ease with which interested parties can locate our article.
Direct current (DC) electronic load is a useful equipment for testing the electrical system. It can emulate various load at a high rating. The electronic load requires a power converter to operate and a linear regulator is a common option. Nonetheless, it is hard to control due to the temperature variation. This paper proposed a DC electronic load using the boost converter. The proposed electronic load operates in the continuous current mode and control using the integral controller. The electronic load using the boost converter is compared with the electronic load using the linear regulator. The results show that the boost converter able to operate as an electronic load with an error lower than 0.5% and response time lower than 13 ms.
The inverter is the principal part of the photovoltaic (PV) systems that assures the direct current/alternating current (DC/AC) conversion (PV array is connected directly to an inverter that converts the DC energy produced by the PV array into AC energy that is directly connected to the electric utility). In this paper, we present a simple method for detecting faults that occurred during the operation of the inverter. These types of faults or faults affect the efficiency and cost-effectiveness of the photovoltaic system, especially the inverter, which is the main component responsible for the conversion. Hence, we have shown first the faults obtained in the case of the short circuit. Second, the open circuit failure is studied. The results demonstrate the efficacy of the proposed method. Good monitoring and detection of faults in the inverter can increase the system's reliability and decrease the undesirable faults that appeared in the PV system. The system behavior is tested under variable parameters and conditions using MATLAB/Simulink.
The increase in power demand has compelled the power system utilities to use series capacitive compensation in long transmission lines.
A problem called sub synchronous resonance (SSR) occurs in long lines because of series compensation. In this paper a flexible a.c. transmission
system (FACTS) device is used along with a proposed controller to damp out the sub synchronous oscillations from the system. An IEEE second
bench mark model is used for investigating the SSR problem, where a three phase short circuit fault is applied on the compensated transmission
line for analysis. A Matlab/Simulink model is used to study the time domain analysis of the system. An improvement in damping is seen with the
use of FACTS device i.e. unified power flow controller (UPFC) which is controlled by a Neural network (NN) based proportional integral (PI)
controller
Impact of hybrid FACTS devices on the stability of the Kenyan power system IJECEIAES
Flexible alternating current transmission system (FACTS) devices are deployed for improving power system’s stability either singly or as a combination. This research investigates hybrid FACTS devices and studies their impact on voltage, small-signal and transient stability simultaneously under various system disturbances. The simulations were done using five FACTS devices-static var compensator (SVC), static synchronous compensator (STATCOM), static synchronous series compensators (SSSC), thyristor controlled series compensator (TCSC) and unified power flow controller (UPFC) in MATLAB’s power system analysis toolbox (PSAT). These five devices were grouped into ten pairs and tested on Kenya’s transmission network under specific contingencies: the loss of a major generating machine and/or transmission line. The UPFC-STATCOM pair performed the best in all the three aspects under study. The settling times were 3 seconds and 3.05 seconds respectively for voltage and rotor angle improvement on the loss of a major generator at normal operation. The same pair gave settling times of 2.11 seconds and 3.12 seconds for voltage and rotor angle stability improvement respectively on the loss of a major transmission line at 140% system loading. From the study, two novel techniques were developed: A performance-based ranking system and classification for FACTS devices.
HIGH EFFICIENT BRIDGELESS BOOST RECTIFIER FOR LOW VOLTAGE ENERGY HARVESTING A...IAEME Publication
A single phase ac-dc bridgeless boost rectifier for low voltage energy harvesting applications is proposed in this paper. The conventional bridge type boost converters for low voltage energy harvesting requires more components hence they suffer from high power loss and require more number of energy storage components like inductors and capacitors. Conventional converters can be modeled for boost operation or buck-boost operation alone. The proposed converter overcomes the above mentioned draw backs of conventional converter. Detailed analysis of proposed convertor is also presented under boost, buck-boost mode operations. The proposed converter operation is analyzed using MATLAB/SIMULINK environment both open loop and closed loop conditions.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
This paper presents a thorough control structure of the distributed generators inside the microgrid during both grid-connected and islanded operation modes. These control structures of the DGs voltage source inverters are implemented in synchronous reference frame (SRF) and controlled using linear PI controllers. By implementing the control structures, the desired real and reactive power can be efficiently transferred to the local loads and the utility load by the microgrid generating units. A modified droop control technique is introduced to facilitate the microgrid performance during both modes of operation. The active and reactive power sharing of the load demand between the utility grid and the microgrid can be performed by this drop control technique during the islanded mode. The system performance during intentional islanding event and utility load increase is investigated. The effectiveness of the offered control structures is confirmed through simulation results during both modes of operation.
Design and Analysis of Three Phase Inverter with Two Buck/Boost MPPTs for DC ...IJERA Editor
Anintegration and operation of a three-phase inverter with twobuck/boost maximum power point trackers
(MPPTs) for dc-distribution applications. In a dc-distribution system, a three phase inverter isrequired to control
the power flow between dc busand three phase ac grid, and to regulate the dc bus to a certainrange of voltages.
A droop regulation mechanism according to the inverter inductor current levels to reduce capacitor size, balance
power flow, and accommodate load variation is proposed. Since thephotovoltaic (PV) array voltage can vary
from 0 to 5000 V, especially with thin-film PV panels, the MPPT topology is formed with buck and boost
converters to operate at the dc-bus voltage around 4000 V, reducing the voltage stress of its followed inverter.
Additionally, the controller can online check the input configuration of the two MPPTs, equally distribute the
PV-array output current to the two MPPTs in parallel operation, and switch control laws to smooth out mode
transition. A comparison between the conventional boost MPPT and the proposed buck/boost MPPT integrated
with a PV inverter is also presented. Asingle-phase bidirectional inverter with two buck/boost maximum power
point trackers (MPPTs) by using the closed loop circuit. This project is workout bySimulink using mat lab.
Recently, LCL has become amongst the most attractive filter used for grid-connected flyback inverters. Nonetheless, the switching of power devices in the inverter configuration creates harmonics that affect the end application behavior and might shorten its lifetime. Furthermore, the resonance frequencies produced by the LCL network contribute to the system instability. This paper proposes a step-by-step guide to designing an LCL filter by considering several key aspects such as the resonance frequency and maximum current ripple. A single-phase grid-connected flyback microinverter with an LCL filter was designed then constructed in the MATLAB/Simulink environment. Several different parameter variations and damping solutions were used to analyze the performance of the circuit. The simulation result shows a promising total harmonic distortion (THD) value below 5% and harmonic suppression up to 14%.
LCL filter design for grid-connected single-phase flyback microinverter: a st...
Similar to Advanced Direct Power Control for Grid-connected Distribution Generation System Based on Fuzzy Logic and Artificial Neural Networks Techniques
The extensive use of non-linear loads in industry becomes increasingly a serious problem that affects the quality of energy delivered to customers. Therefore, the shunt active power filter (SAPF) has emerged as an important industrial tool to eliminate induced harmonic currents and compensating of reactive power. This paper proposes an improved control configuration for SAPF based on a modern technique called predictive direct power control (Predictive-DPC). The principle of this control is based on the direct regulation of the instantaneous active and reactive powers to guarantee a good energy quality on the grid side. For this purpose the appropriate average voltage vector which cancels power tracking errors is calculated by a simple predictive model at the bigining of each control period. This type of control includes various features such as the lack of look up table (LUTs) and closed current loops and the constant switching frequency is achieved through the use of PWM modulation. The results of the simulation process show a high performance in the steady and transient state function for predictive-DPC control that might be a reasonable alternative to conventional DPC in the field of active power filtering.
In this paper, a detail design and description of a predictive current control scheme are adopted for three-phase grid-connected two-level inverter and its application in wind energy conversion systems. Despite its advantages, the predictive current controller is very sensitive to parameter variations which could eventually affected on system stability. To solve this problem, an estimation technique proposed to identify the value of harmonic filter parameter based on Model reference adaptive system (MRAS). Lyapunov stability theory is selected to guarantee a robust adaptation and stable response over large system parameter variation. The simulation results shows the efficiency of the proposed techniques to improve the current tracking performance.
Power quality optimization using a novel backstepping control of a three-phas...IJECEIAES
A novel nonlinear backstepping controller based on direct current (DC) link voltage control is proposed in three-phase grid-connected solar photovoltaic (PV) systems to control the active and reactive power flow between the PV system and the grid with improved power quality in terms of pure sinusoidal current injection with lower total harmonic distortion (THD), as well as to ensure unity power factor, or to compensate for reactive power required by the load, i.e., the electrical grid. The output power of the PV array is supplied to the grid through a boost converter with maximum power point tracking (MPPT) control and an inverter. Simulation results of the proposed controller show good robustness under nominal conditions, parameter variations, and load disturbances, which presents the main advantage of this controller as compared to an existing controller. The performance of this work was evaluated using a MATLAB/Simulink environment.
In this paper, using a neural controller and a genetic optimization algorithm to control the voltage as well as, control the frequency of the grid along with the management of the reactive power of the micro-grid to control the output power during islanding using Simultaneous bilateral power converters with voltage/frequency droop strategy and optimization of PI coefficients of parallel power converters by genetic-neural micro-grid algorithm to suppress AC side-current flow that increases stability and improvement of conditions frequency and voltage are discussed. Given the performance of the micro-grid in two simulation scenarios, namely transition from on-grid to off-grid, the occurrence of a step change in load in island mode as well as return to working mode is connected. The ability to detect the robust performance and proper performance of two-level neural controller. The controller performance time was also very good, indicating the appropriate features of the method used to design the controller, namely two-level neural, genetics. The main advantage of this method is its simplicity of design. The method used is also efficient and resistant to changes in the system, which results from the simulations.
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.
Modeling and simulation of three phases cascaded H-bridge grid-tied PV inverterjournalBEEI
In this paper a control scheme for three phase seven level cascaded H-bridge inverter for grid tied PV system is presented. As power generation from PV depends on varing environmental conditions, for extractraction of maximum power from PV array, fuzzy MPPT controller is incorporated with each PV array. It gives fast and accurate response. To maintain the grid current sinusoidal under varying conditions, a digital PI controller scheme is adopted. A MATLAB/Simulink model is developed for this purpose and results are presented. At last THD analysis is carried out in order to validate the performance of the overall system. As discussed, with this control strategy the balanced grid current is obtained keeping THD values with in the specified range of IEEE-519 standard.
This paper presents an analysis of virtual-flux direct power control (VFDPC) technique for the three-phase pulse width modulation (PWM) ac-dc converter. The proposed VFDPC is developed by assuming the grid voltage and converter line filters quantities are related to a virtual three-phase ac motor. The controller works with less number of sensors by eliminating the voltage sensors used for measuring the three-phase grid voltage. The grid virtual flux which is proportional to the grid voltage will be estimated from the information of converter switching states, line current, and dc-link output voltage. Several analyses are performed in order to study the steady state and dynamic performance of the converter, particularly during the load and DC voltage output reference variations. The proportional integral (PI) controller at the outer voltage control loop of VFDPC is tuned properly and the entire PWM ac-dc converter system is simulated using MATLAB/Simulink to ensure the dc output voltage follow the desired output voltage under steady state and dynamic conditions. Ac-dc converter utilizing the proposed VFDPC is able to generate three-phase input current waveforms that are almost sinusoidal with low harmonics contents which is less than 5% and near unity power factor (pf) operation.
CONTROL OF BATTERY OPERATED SYSTEM WITH A DC-DC BOOSTCONVERTER FED DSTATCOM U...ijiert bestjournal
This paper presents a comprehensive survey of DSTATCOM control strategies put forward recently. It is
aimed at providing a broad perspective on the status of DSTATCOM control methods to researchers and
application engineers dealing with harmonic suppression issues. Many control techniques have been
designed, developed, and realized for active filters in recent years. The proposed DSTATCOM consists of a
three-leg Voltage Source Converter (VSC) with a dc bus capacitor. The PV array or battery operated boost
converter is proposed to maintain the dc link voltage of the dc bus capacitor for continuous compensation
for the load. This paper presents to evaluate the performance comparison of two control strategies for
extracting the reference currents to control the proposed DSTATCOM. The two control methods are
Synchronous Reference Frame (SRF) theory and IcosΦ algorithm. The performance of the DSTATCOM is
validated using MATLAB software with its simulink and Power System Block set (PSB) toolboxes. The
simulation results for the two control methods are compared to validate the superior performance of the
IcosΦ algorithm.
The power generation using solar photovoltaic (PV) system in microgrid requires energy storage system due to their dilute and intermittent nature. The system requires efficient control techniques to ensure the reliable operation of the microgrid. This work presents dynamic power management using a decentralized approach. The control techniques in microgrid including droop controllers in cascade with proportional-integral (PI) controllers for voltage stability and power balance have few limitations. PI controllers alone will not ensure microgrid’s stability. Their parameters cannot be optimized for varying demand and have a slow transient response which increases the settling time. The droop controllers have lower efficiency. The load power variation and steady-state voltage error make the droop control ineffective. This paper presents a control scheme for dynamic power management by incorporating the combined PI and hysteresis controller (CPIHC) technique. The system becomes robust, performs well under varying demand conditions, and shows a faster dynamic response. The proposed DC microgrid has solar PV as an energy source, a lead-acid battery as the energy storage system, constant and dynamic loads. The simulation results show the proposed CPIHC technique efficiently manages the dynamic power, regulates DC link voltage and battery’s state of charge (SoC) compared to conventional combined PI and droop controller (CPIDC).
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
This work presents a study of the three-phase parallel active power filter and the various controllers used in its control. Moreover, in order to improve the quality of electrical energy, by making it conform to the new normative constraints, we have also been led to develop and apply advanced automation methods. In this framework, this paper reports of several regulatory structures : fuzzy logic, PWM, new space vector PWM (NSVPWM), space vector PWM (SVPWM), HYSTERESIS moreover, in order to produce a parallel active filter, a thorough study of experimental feasibility was carried out, taking into account the industrial constraints of the product both in its design and its application.
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.
This article presents nonlinear control of wind conversion chain connected to the grid based on a permanent magnet synchronous generator. The control objectives are threefold; i) forcing the generator speed to track a varying reference signal in order to extract the maximum power at different wind speed (MPPT); ii) regulating the rectifier output capacitor voltage; iii) reducing the harmonic and reactive currents injected in the grid. This means that the inverter output current must be sinusoidal and in phase with the AC supply voltage (PFC). To this end, a nonlinear state-feedback control is developed, based on the average nonlinear model of the whole controlled system. This control strategy involves backstepping approach, Lyapunov stability and other tools from theory of linear systems. The proposed state-feedback control strategy is tested by numerical simulation which shows that the developed controller reaches its objectives.
The work presented in this paper is devoted to the control of a photovoltaic system connected to grid by a three level diode clamed inverter. A control structure based on three parts: dc link voltage control, power injected control and current control is proposed. In this work, the random PWM strategy is used to generate control signals for the multilevel inverter used us an interface to connect photovoltaic generators to the grid. Numerical simulations are performed using MATLAB / Simulink software, the simulation results for the proposed system indicate the performances of the proposed control structure, minimization of harmonics by the random PWM strategy applied and injection to the grid more active power by the multilevel inverter structure.
Two fuzzy logic controllers are proposed in this paper to control a three phase inverter for grid connected photovoltaic system. The first controller was used to predict the DC voltage that allows the three phase inverter to track the maximum power point of photovoltaic array under different environmental conditions such as irradiances and temperature. The second was used to control the active power and reactive power injected into the grid in order to inject the maximum active power produced by photovoltaic systems into grid with high efficiency and low total harmonic distortion using the same three phase inverter. The system components are photovoltaic array, DC link voltage, three-phase inverter, inverter control, LC filter, transformer and grid. To verify the effectivnesse of the introdueced system, modeling and simulation are verified in Matlab/Simulink due to its frequent use and its effectiveness.
A novel efficient adaptive-neuro fuzzy inference system control based smart ...IJECEIAES
A novel adaptive-neuro fuzzy inference system (ANFIS) control algorithm-based smart grid to solve power quality issues is investigated in this paper. To improve the steady-state and transient response of the solar-wind and grid integrated system proposed ANFIS controller works very well. Fuzzy maximum power point tracking (MPPT) algorithm-based DC-DC converters are utilized to extract maximum power from solar. A permanent magnet synchronous generator (PMSG) is employed to get maximum power from wind. To maximize both power generations, back-to-back voltage source converters (VSC) are operated with an intelligent ANFIS controller. Optimal power converters are adopted this proposed methodology and improved the overall performance of the system to an acceptable limit. The simulation results are obtained for a different mode of smart grid and non-linear fault conditions and the proven proposed control algorithm works well.
The study made in this paper concerns the use of the voltage-oriented control (VOC) of three-phase pulse width modulation (PWM) rectifier with constant switching frequency. This control method, called voltage-oriented controlwith space vector modulation (VOC-SVM). The proposed control scheme has been founded on the transformation between stationary (α-β) and and synchronously rotating (d-q) coordinate system, it is based on two cascaded control loops so that a fast inner loop controls the grid current and an external loop DC-link voltage, while the DC-bus voltage is maintained at the desired level and ansured the unity power factor operation. So, the stable state performance and robustness against the load’s disturbance of PWM rectifiers are boths improved. The proposed scheme has been implemented and simulated in MATLAB/Simulink environment. The control system of the VOC-SVM strategy has been built based on dSPACE system with DS1104 controller board. The results obtained show the validity of the model and its control method. Compared with the conventional SPWM method, the VOC-SVM ensures high performance and fast transient response.
Similar to Advanced Direct Power Control for Grid-connected Distribution Generation System Based on Fuzzy Logic and Artificial Neural Networks Techniques (20)
The aim of this research is the speed tracking of the permanent magnet synchronous motor (PMSM) using an intelligent Neural-Network based adapative backstepping control. First, the model of PMSM in the Park synchronous frame is derived. Then, the PMSM speed regulation is investigated using the classical method utilizing the field oriented control theory. Thereafter, a robust nonlinear controller employing an adaptive backstepping strategy is investigated in order to achieve a good performance tracking objective under motor parameters changing and external load torque application. In the final step, a neural network estimator is integrated with the adaptive controller to estimate the motor parameters values and the load disturbance value for enhancing the effectiveness of the adaptive backstepping controller. The robsutness of the presented control algorithm is demonstrated using simulation tests. The obtained results clearly demonstrate that the presented NN-adaptive control algorithm can provide good trackingperformances for the speed trackingin the presence of motor parameter variation and load application.
This paper presents a fast and accurate fault detection, classification and direction discrimination algorithm of transmission lines using one-dimensional convolutional neural networks (1D-CNNs) that have ingrained adaptive model to avoid the feature extraction difficulties and fault classification into one learning algorithm. A proposed algorithm is directly usable with raw data and this deletes the need of a discrete feature extraction method resulting in more effective protective system. The proposed approach based on the three-phase voltages and currents signals of one end at the relay location in the transmission line system are taken as input to the proposed 1D-CNN algorithm. A 132kV power transmission line is simulated by Matlab simulink to prepare the training and testing data for the proposed 1D- CNN algorithm. The testing accuracy of the proposed algorithm is compared with other two conventional methods which are neural network and fuzzy neural network. The results of test explain that the new proposed detection system is efficient and fast for classifying and direction discrimination of fault in transmission line with high accuracy as compared with other conventional methods under various conditions of faults.
Among the most widespread renewable energy sources is solar energy; Solar panels offer a green, clean, and environmentally friendly source of energy. In the presence of several advantages of the use of photovoltaic systems, the random operation of the photovoltaic generator presents a great challenge, in the presence of a critical load. Among the most used solutions to overcome this problem is the combination of solar panels with generators or with the public grid or both. In this paper, an energy management strategy is proposed with a safety aspect by using artificial neural networks (ANNs), in order to ensure a continuous supply of electricity to consumers with a maximum solicitation of renewable energy.
In this paper, the artificial neural network (ANN) has been utilized for rotating machinery faults detection and classification. First, experiments were performed to measure the lateral vibration signals of laboratory test rigs for rotor-disk-blade when the blades are defective. A rotor-disk-blade system with 6 regular blades and 5 blades with various defects was constructed. Second, the ANN was applied to classify the different x- and y-axis lateral vibrations due to different blade faults. The results based on training and testing with different data samples of the fault types indicate that the ANN is robust and can effectively identify and distinguish different blade faults caused by lateral vibrations in a rotor. As compared to the literature, the present paper presents a novel work of identifying and classifying various rotating blade faults commonly encountered in rotating machines using ANN. Experimental data of lateral vibrations of the rotor-disk-blade system in both x- and y-directions are used for the training and testing of the network.
This paper focuses on the artificial bee colony (ABC) algorithm, which is a nonlinear optimization problem. is proposed to find the optimal power flow (OPF). To solve this problem, we will apply the ABC algorithm to a power system incorporating wind power. The proposed approach is applied on a standard IEEE-30 system with wind farms located on different buses and with different penetration levels to show the impact of wind farms on the system in order to obtain the optimal settings of control variables of the OPF problem. Based on technical results obtained, the ABC algorithm is shown to achieve a lower cost and losses than the other methods applied, while incorporating wind power into the system, high performance would be gained.
The significance of the solar energy is to intensify the effectiveness of the Solar Panel with the use of a primordial solar tracking system. Here we propounded a solar positioning system with the use of the global positioning system (GPS) , artificial neural network (ANN) and image processing (IP) . The azimuth angle of the sun is evaluated using GPS which provide latitude, date, longitude and time. The image processing used to find sun image through which centroid of sun is calculated and finally by comparing the centroid of sun with GPS quadrate to achieve optimum tracking point. Weather conditions and situation observed through AI decision making with the help of IP algorithms. The presented advance adaptation is analyzed and established via experimental effects which might be made available on the memory of the cloud carrier for systematization. The proposed system improve power gain by 59.21% and 10.32% compare to stable system (SS) and two-axis solar following system (TASF) respectively. The reduced tracking error of IoT based Two-axis solar following system (IoT-TASF) reduces their azimuth angle error by 0.20 degree.
Kosovo has limited renewable energy resources and its power generation sector is based on fossil fuels. Such a situation emphasizes the importance of active research and efficient use of renewable energy potential. According to the analysis of meteorological data for Kosovo, it can be concluded that among the most attractive potential wind power sites are the locations known as Kitka (42° 29' 41" N and 21° 36' 45" E) and Koznica (42° 39′ 32″ N, 21° 22′30″E). The two terrains in which the analysis was carried out are mountain areas, with altitudes of 1142 m (Kitka) and 1230 m (Koznica). the same measuring height, about 84 m above the ground, is obtained for these average wind speeds: Kitka 6,667 m/s and Koznica 6,16 m/s. Since the difference in wind speed is quite large versus a difference in altitude that is not being very large, analyses are made regarding the terrain characteristics including the terrain relief features. In this paper it will be studied how much the roughness of the terrain influences the output energy. Also, that the assumption to be taken the same as to how much they will affect the annual energy produced.
Large-scale grid-tied photovoltaic (PV) station are increasing rapidly. However, this large penetration of PV system creates frequency fluctuation in the grid due to the intermittency of solar irradiance. Therefore, in this paper, a robust droop control mechanism of the battery energy storage system (BESS) is developed in order to damp the frequency fluctuation of the multi-machine grid system due to variable active power injected from the PV panel. The proposed droop control strategy incorporates frequency error signal and dead-band for effective minimization of frequency fluctuation. The BESS system is used to consume/inject an effective amount of active power based upon the frequency oscillation of the grid system. The simulation analysis is carried out using PSCAD/EMTDC software to prove the effectiveness of the proposed droop control-based BESS system. The simulation result implies that the proposed scheme can efficiently curtail the frequency oscillation.
This study investigates experimentally the performance of two-dimensional solar tracking systems with reflector using commercial silicon based photovoltaic module, with open and closed loop control systems. Different reflector materials were also investigated. The experiments were performed at the Hashemite University campus in Zarqa at a latitude of 32⁰, in February and March. Photovoltaic output power and performance were analyzed. It was found that the modified photovoltaic module with mirror reflector generated the highest value of power, while the temperature reached a maximum value of 53 ̊ C. The modified module suggested in this study produced 5% more PV power than the two-dimensional solar tracking systems without reflector and produced 12.5% more PV power than the fixed PV module with 26⁰ tilt angle.
This paper focuses on the modeling and control of a wind energy conversion chain using a permanent magnet synchronous machine. This system behaves a turbine, a generator, DC/DC and DC/AC power converters. These are connected on both sides to the DC bus, where the inverter is followed by a filter which is connected to the grid. In this paper, we have been used two types of controllers. For the stator side converter, we consider the Takagi-Sugeno approach where the parameters of controller have been computed by the theory of linear matrix inequalities. The stability synthesis has been checked using the Lyapunov theory. According to the grid side converter, the proportional integral controller is exploited to keep a constant voltage on the DC bus and control both types of powers. The simulation results demonstrate the robustness of the approach used.
The development of modeling wind speed plays a very important in helping to obtain the actual wind speed data for the benefit of the power plant planning in the future. The wind speed in this paper is obtained from a PCE-FWS 20 type measuring instrument with a duration of 30 minutes which is accumulated into monthly data for one year (2019). Despite the many wind speed modeling that has been done by researchers. Modeling wind speeds proposed in this study were obtained from the modified Rayleigh distribution. In this study, the Rayleigh scale factor (Cr) and modified Rayleigh scale factor (Cm) were calculated. The observed wind speed is compared with the predicted wind characteristics. The data fit test used correlation coefficient (R2), root means square error (RMSE), and mean absolute percentage error (MAPE). The results of the proposed modified Rayleigh model provide very good results for users.
This paper deals with an advanced design for a pump powered by solar energyto supply agricultural lands with water and also the maximum power point is used to extract the maximum value of the energy available inside the solar panels and comparing between techniques MPPT such as Incremental conductance, perturb & observe, fractional short current circuit, and fractional open voltage circuit to find the best technique among these. The solar system is designed with main parts: photovoltaic (PV) panel, direct current/direct current (DC/DC) converter, inverter, filter, and in addition, the battery is used to save energy in the event that there is an increased demand for energy and not to provide solar radiation, as well as saving energy in the case of generation more than demand. This work was done using the matrix laboratory (MATLAB) simulink program.
The objective of this paper is to provide an overview of the current state of renewable energy resources in Bangladesh, as well as to examine various forms of renewable energies in order to gain a comprehensive understanding of how to address Bangladesh's power crisis issues in a sustainable manner. Electricity is currently the most useful kind of energy in Bangladesh. It has a substantial influence on a country's socioeconomic standing and living standards. Maintaining a stable source of energy at a cost that is affordable to everyone has been a constant battle for decades. Bangladesh is blessed with a wealth of natural resources. Bangladesh has a huge opportunity to accelerate its economic development while increasing energy access, livelihoods, and health for millions of people in a sustainable way due to the renewable energy system.
When the irradiance distribution over the photovoltaic panels is uniform, the pursuit of the maximum power point is not reached, which has allowed several researchers to use traditional MPPT techniques to solve this problem Among these techniques a PSO algorithm is used to have the maximum global power point (GMPPT) under partial shading. On the other hand, this one is not reliable vis-à-vis the pursuit of the MPPT. Therefore, in this paper we have treated another technique based on a new modified PSO algorithm so that the power can reach its maximum point. The PSO algorithm is based on the heuristic method which guarantees not only the obtaining of MPPT but also the simplicity of control and less expensive of the system. The results are obtained using MATLAB show that the proposed modified PSO algorithm performs better than conventional PSO and is robust to different partial shading models.
A stable operation of wind turbines connected to the grid is an essential requirement to ensure the reliability and stability of the power system. To achieve such operational objective, installing static synchronous compensator static synchronous compensator (STATCOM) as a main compensation device guarantees the voltage stability enhancement of the wind farm connected to distribution network at different operating scenarios. STATCOM either supplies or absorbs reactive power in order to ensure the voltage profile within the standard-margins and to avoid turbine tripping, accordingly. This paper present new study that investigates the most suitable-location to install STATCOM in a distribution system connected wind farm to maintain the voltage-levels within the stability margins. For a large-scale squirrel cage induction generator squirrel-cage induction generator (SCIG-based) wind turbine system, the impact of STATCOM installation was tested in different places and voltage-levels in the distribution system. The proposed method effectiveness in enhancing the voltage profile and balancing the reactive power is validated, the results were repeated for different scenarios of expected contingencies. The voltage profile, power flow, and reactive power balance of the distribution system are observed using MATLAB/Simulink software.
The electrical and environmental parameters of polymer solar cells (PSC) provide important information on their performance. In the present article we study the influence of temperature on the voltage-current (I-V) characteristic at different temperatures from 10 °C to 90 °C, and important parameters like bandgap energy Eg, and the energy conversion efficiency η. The one-diode electrical model, normally used for semiconductor cells, has been tested and validated for the polemeral junction. The PSC used in our study are formed by the poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM). Our technique is based on the combination of two steps; the first use the Least Mean Squares (LMS) method while the second use the Newton-Raphson algorithm. The found results are compared to other recently published works, they show that the developed approach is very accurate. This precision is proved by the minimal values of statistical errors (RMSE) and the good agreement between both the experimental data and the I-V simulated curves. The obtained results show a clear and a monotonic dependence of the cell efficiency on the studied parameters.
The electrical distribution network is undergoing tremendous modifications with the introduction of distributed generation technologies which have led to an increase in fault current levels in the distribution network. Fault current limiters have been developed as a promising technology to limit fault current levels in power systems. Though, quite a number of fault current limiters have been developed; the most common are the superconducting fault current limiters, solid-state fault current limiters, and saturated core fault current limiters. These fault current limiters present potential fault current limiting solutions in power systems. Nevertheless, they encounter various challenges hindering their deployment and commercialization. This research aimed at designing a bridge-type nonsuperconducting fault current limiter with a novel topology for distribution network applications. The proposed bridge-type nonsuperconducting fault current limiter was designed and simulated using PSCAD/EMTDC. Simulation results showed the effectiveness of the proposed design in fault current limiting, voltage sag compensation during fault conditions, and its ability not to affect the load voltage and current during normal conditions as well as in suppressing the source powers during fault conditions. Simulation results also showed very minimal power loss by the fault current limiter during normal conditions.
This paper provides a new approach to reducing high-order harmonics in 400 Hz inverter using a three-level neutral-point clamped (NPC) converter. A voltage control loop using the harmonic compensation combined with NPC clamping diode control technology. The capacitor voltage imbalance also causes harmonics in the output voltage. For 400 Hz inverter, maintain a balanced voltage between the two input (direct current) (DC) capacitors is difficult because the pulse width modulation (PWM) modulation frequency ratio is low compared to the frequency of the output voltage. A method of determining the current flowing into the capacitor to control the voltage on the two balanced capacitors to ensure fast response reversal is also given in this paper. The combination of a high-harmonic resonator controller and a neutral-point voltage controller working together on the 400 Hz NPC inverter structure is given in this paper.
This paper presents a new simplified cascade multiphase DC-DC buck power converter suitable for low voltage and large current applications. Cascade connection enables very low voltage ratio without using very small duty cycles nor transformers. Large current with very low ripple content is achieved by using the multiphase technique. The proposed converter needs smaller number of components compared to conventional cascade multiphase DC-DC buck power converters. This paper also presents useful analysis of the proposed DC-DC buck power converter with a method to optimize the phase and cascade number. Simulation and experimental results are included to verify the basic performance of the proposed DC-DC buck power converter.
A hybrid DC/DC/AC converter connected to the grid without a three-phase transformer is controlled. The decentralized control method is applied to the hybrid DC-DC converter such that the maximum power of PV flows to the grid side. This controller must charge and discharge the battery at the proper time. It must also regulate DC-link voltage. An additional advantage of the proposed control is that the three-phase inverter does not need a separate controller such as PWM and SPWM. A simple technique is used for creating the desired phase shift in the three-phase inverter, which makes the active and reactive power of the inverter controllable. A new configuration is also proposed to transmit and manage the generation power of PV. In this scheme, the battery and fuel cell are employed as an auxiliary source to manage the generation power of PV. Finally, a real-time simulation is performed to verify the effectiveness of the proposed controller and system by considering the real characteristics of PV and FC.
More from International Journal of Power Electronics and Drive Systems (20)
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
6th International Conference on Machine Learning & Applications (CMLA 2024)ClaraZara1
6th International Conference on Machine Learning & Applications (CMLA 2024) will provide an excellent international forum for sharing knowledge and results in theory, methodology and applications of on Machine Learning & Applications.
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.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
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.
HEAP SORT ILLUSTRATED WITH HEAPIFY, BUILD HEAP FOR DYNAMIC ARRAYS.
Heap sort is a comparison-based sorting technique based on Binary Heap data structure. It is similar to the selection sort where we first find the minimum element and place the minimum element at the beginning. Repeat the same process for the remaining elements.
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.
2. ISSN: 2088-8694
IJPEDS Vol. 8, No. 3, September 2017 : 979 – 989
980
Various control strategies of voltage source inverter in grid connected photovoltaic systems have
been presented in the literature. These control techniques are classified according to their principles for using
the control loops of the powers and the currents in two categories: direct power control and voltage oriented
control (VOC). The DPC strategy directly uses the instantaneous active and reactive power as control
variables [7]; it is similar to the direct torque control (DTC) for induction motors [8]. This control method
has two configurations: one used the voltage vector named voltage-based direct power control (V-DPC) and
the other uses the virtual flux called virtual-flux-based direct power control (VF-DPC) [9]. However, the
DPC has main advantages such as, a simple algorithm, no separate PWM block, no current regulation loops,
and it has good dynamic performance. While VOC strategy allows orienting the current vector in the same
orientation as the voltage vector of the grid, where the current control is performed in the d-q synchronous
frame. This technique is similar to the vector control of the electric machines. The VOC can also use the
virtual flux to estimate the grid voltages; this method is known under the name virtual flux oriented control
(VFOC) [10]. Moreover, there are other types of controls that are used in the control of three phase voltage
source inverter connected to the utility grid such as, non-linear control based on the sliding mode [11] and
nonlinear control based on input-output feedback linearization [12].
In this paper, we propose a new structure of direct power control based on intelligent techniques for
three phase VSI connected to the utility grid. This new DPC consists, on the one hand, to replace the
conventional hysteresis regulators by fuzzy logic controllers. On the other hand, it allows replacing the
predefined switching table by a selector based on the artificial neural networks approach. Moreover, this
intelligent control constitutes a good solution to problems related to the conventional control. It allows
ensuring a unity power factor, well control the active and reactive powers injected in utility grid at their
references as well reduced considerably its fluctuations and also reduced the harmonic disturbances.
The paper is organized as follows: Section 2 presents the modeling of the three phase voltage source
inverter in grid connected photovoltaic systems, the principle of the new DPC structure is exposed in
section 3, section 4 is devoted to the fuzzy logic controllers design, the artificial neural networks selector are
described in section 5, section 6 shows the simulation results of the overall system. Finally, a conclusion is
given in section 7.
2. MODELING OF THREE PHASE VOLTAGE SOURCE INVERTER
Figure 1 shows the overall configuration of the proposed system. It is consists of a photovoltaic
system connected to a three phase voltage source inverter, which in turn connected to a three phase
inductance in order to transfer power to utility grid.
Figure 1. Functional diagram of the proposed system
3. IJPEDS ISSN: 2088-8694
Advanced Direct Power Control for Grid-Connected Distribution Generation System .... (Mustapha Jamma)
981
Figure 2 shows the equivalent diagram of a grid connected three phase DC/AC converter in α-β coordinates
system.
Figure 2. Equivalent diagram of a grid connected DC/AC converter
From the Figure 2, the mathematical model which governs this converter as ideal voltage source can be
expressed in α-β coordinates as follow:
dI
V U L
dt
dI
V U L
dt
(1)
For this three phase system, the grid active and reactive power can be determined by several techniques [13]
such as, the measurement of currents and grid voltages. In stationary α-β coordinates, the grid active and
reactive power is expressed as follow:
3
( . . )
2
3
( . . )
2
p U I U I
q U I U I
(2)
3. PRINCIPLES OF THE PROPOSED DPC STRATEGY
The DPC is the control structure that directly uses the instantaneous active and reactive power as
control variables. The switching states of the switches of the three phase inverter are determined using a
selector based on artificial neural networks approach, whose these inputs are the sector where is the position
of the voltage vector of the grid and the digitized errors dp, dq, between the values of the instantaneous active
and reactive power p, q, and their reference values pref, qref [14]. These errors are provided by fuzzy logic
controllers.This control technique is similar to the direct torque control of induction machines whose the
torque and the stator flux are the controlled quantities [8]. The simplified representation of the new DPC
based on artificial neural networks approach and on fuzzy logic controllers for the three phase voltage source
inverter is shown in Figure 3, in which (Sa, Sb, Sc) are the switching states of the VSI.
In order to obtain a unity power factor, the reference of reactive power is directly imposed equal to
zero. While the DPC technique uses the angular position of the grid voltage vector to determine the sector of
work, for that, the α-β plane is divided into twelve equal sectors, as shown in Figure 4. These sectors are
determined numerically as follow:
( 1)
6 6
n
n n
; n=1,2,…,12 (3)
Where n is the sector number.
4. ISSN: 2088-8694
IJPEDS Vol. 8, No. 3, September 2017 : 979 – 989
982
Figure 3. Block diagram of the proposed DPC strategy
Figure 4. Sectors and voltage vectors of VSI
4. THE PROPOSED FUZZY LOGIC CONTROLLERS
The fuzzy logic control is a strategy used in artificial intelligence. It allows determining a very
efficient control law compared to the traditional controller. While the fuzzy controller is based on three
important steps: fuzzification, inference engine and defuzzification [15].
In this work, the fuzzy logic system has two inputs for the active power block and two inputs for the
reactive power block. These inputs are the errors of active power ep, reactive power eq and their variations
dep, deq; they are determined respectively by the following expressions:
5. IJPEDS ISSN: 2088-8694
Advanced Direct Power Control for Grid-Connected Distribution Generation System .... (Mustapha Jamma)
983
( ) ( ) ( )
( ) ( ) ( 1)
p ref
p p p
e k p k p k
de k e k e k
(4)
And
( ) ( ) ( )
( ) ( ) ( 1)
q ref
q q q
e k q k q k
de k e k e k
(5)
4.1. Fuzzification
In order to perform the fuzzification of the errors of active and reactive powers, we have employed
the trapezoidal membership functions. Thus, the two fuzzy sets chosen to accomplish this fuzzification are: N
(Negative), P (Positive). The output variables are the two logic outputs dp and dq of two fuzzy controllers, the
discourse universe of its output is divided into two fuzzy sets, its membership functions are forms of type
singleton. The membership functions of the input and output variables are presented in Figures 5, 6 and 7.
Figure 5. Membership functions for active power
Figure 6. Membership functions for reactive power
6. ISSN: 2088-8694
IJPEDS Vol. 8, No. 3, September 2017 : 979 – 989
984
Figure 7. Membership functions for the output variable of the active and reactive power
4.2. Inference engine
The input linguistic variables ep, dep, eq and deq attack the inference engine where the whole
linguistic rules are executed. The fuzzy sets of output are then determined using the fuzzy implication
technique of Mamdani [16]. The Table 1 indicates the control linguistic rules of active and reactive power;
these rules can be written in the following form:
IF (ep IS N) AND (dep IS P) THEN (dp IS P)
IF (eq IS N) AND (deq IS P) THEN (dq IS P)
Table 1. The control linguistic rules of active and reactive power
4.3. Defuzzification
This defuzzification block allows transforming linguistic variables from the two fuzzy controllers to
real variables. To perform this task, several techniques have been proposed in the literature [17]. In our case,
the center of gravity technique is used to perform this deffuzzification. The conventional switching table of
the DPC is given in Table 2. It was built based on the outputs of two fuzzy controllers dp, dq and the sector
position of work ɣn.
Table 2. Switching table of the DPC
5. THE PROPOSED NEURAL NETWORKS SELECTOR
The development of neural networks is relatively recent. The origin of these latter comes from the
modeling test of biological neuron [18]. They form a set of nonlinear functions allowing building by learning,
a vast family of models and non-linear correctors [19]. The information in the neural networks spreads from
one layer to another. We can distinguish three types of layers: an input layer, hidden layers and the output
layer [20]. The neural networks are used in many areas include the classification, pattern recognition, the
static or dynamic modeling of process and the control of industrial processes [21].
ep,q
dep,q N p
N N N
p p p
dp dq ɣ1 ɣ2 ɣ3 ɣ4 ɣ5 ɣ6 ɣ7 ɣ8 ɣ9 ɣ10 ɣ11 ɣ12
1 0 V1 V2 V2 V3 V3 V4 V4 V5 V5 V6 V6 V1
1 1 V6 V1 V1 V2 V2 V3 V3 V4 V4 V5 V5 V6
0 0 V2 V3 V3 V4 V4 V5 V5 V6 V6 V1 V1 V2
0 1 V7 V7 V0 V0 V7 V7 V0 V0 V7 V7 V0 V0
7. IJPEDS ISSN: 2088-8694
Advanced Direct Power Control for Grid-Connected Distribution Generation System .... (Mustapha Jamma)
985
In this work, we proposed to change the conventional selector of the switching sequences of the
three phase VSI by a neural networks selector, in order to reduce the ripples of active and reactive power.
The inputs of the neural selector are the angular position of the voltage vector and the power errors provided
by the fuzzy logic controllers. So, these outputs are the switching states of the VSI. Figure 8 shows the
architecture of the neural networks used. While, the Table 3 shows the parameters of the neural networks
used. Thus, this neural selector is generated by Matlab/ Simulink environment.
Figure 8. Architecture of ANN selector
Table 3. Parameters of the neural networks used
Number of neurons in the input layer 3 neurons
Number of neurons in the hidden layer 20 neurons
Number of neurons in the output layer 3 neurons
Number of epochs 1500
Mean square error 10-6
Training algorithm of network Backpropagation algorithm
Type of activation functions Tansig and Purelin
6. SIMULATION RESULTS AND ANALYSIS
In order to show the performance of the new DPC strategy based on artificial neural networks
approach and fuzzy logic controllers applied to a grid connected three phase DC/AC converter system, we
present, in this section, the different results of numerical simulation. The system parameters are defined in
the Table 4.
Table 4. Electrical parameters of system
Parameters of system Value
Switching frequency 10 KHz
Line inductance L 0.01 H
DC-bus capacitor C 2400 µF
Grid phase voltage U 50 V
Grid frequency f 50 Hz
dc-bus voltage Vdc 113 V
The simulations are performed using Matlab/Simulink environment in steady and transient state.
This simulation study was conducted for the purpose to present and explain the operating stability of the new
DPC technique, and also to expose these dynamic performances. Figures 9-15 show the simulation results of
the new DPC scheme in steady-state under a unity power factor operation. The simulation of the twelve
sectors of the voltage vector in the α-β coordinate was shown in Figure 9. The Figure 10 shows the switching
states Sa, Sb and Sc of the switches of the three phase VSI established by the ANN selector. The waveform of
the DC-bus voltage Vdc is illustrated in Figure 11. The output phase voltage of the voltage source inverter is
given in Figure 12. Figure 13 shows the waveform of the active and reactive power injected into utility grid.
According to this figure, it was found that the DPC strategy based on fuzzy logic controllers, which do not
require any exacte mathematical model of the studied system, and the ANN approach provide better control
of active and reactive power and also a considerable minimization of the ripples of these powers during a
fixed time period. Figure 14 illustrates the waveforms of the currents injected into the grid under a UPF, it
may be noted that these currents have almost sinusoidal forms, which gives a reduced THD which is 0.17%.
The current Ia and the voltage Ua injected into the grid are in phase which illustrates a UPF, as shown in
Figure 15.
8. ISSN: 2088-8694
IJPEDS Vol. 8, No. 3, September 2017 : 979 – 989
986
Figure 9. The twelve sectors of the voltage vector
Figure 10. The switching states Sa, Sb and Sc of the VSI
Figure 11. DC bus voltage waveform
Figure 12. Waveform of the output voltage of the VSI
9. IJPEDS ISSN: 2088-8694
Advanced Direct Power Control for Grid-Connected Distribution Generation System .... (Mustapha Jamma)
987
Figure 13. Waveform of the injected active and reactive power into grid
Figure 14. The current waveform Ia, Ib and Ic
Figure 15. Phase grid voltage and grid currents at UPF
The waveforms of Figures 16-18 present the simulations results of the new DPC scheme in transient
state under a UPF, for a step change of the reference active power of pref = 0 W to pref = 100 W at t = 0.075 s.
The Figure 16 represents the waveforms of active and reactive power transferred into utility grid, we can note
here that the active power has a good tracking of its reference without affecting the reactive power (UPF),
which illustrates a decoupled control of this powers. The currents injected into utility grid responds well to
the variation of the reference active power, he establishes quickly after a transition phase as shown in
Figure 17. The current Ia and the voltage Ua are in phase (UPF) as shown in Figure 18.
It is evident from the simulation results that the DPC scheme based on artificial neural networks
approach and fuzzy logic controller for grid connected voltage source inverter, in steady and transient state,
give better responses in terms of overshoot, fast response and static error. Furthermore, they present an
improvement of the robustness, excellent dynamic performance of active and reactive power control, as well
as a significant mitigation of current ripples which seems sinusoidal, which gives a reduced THD.
10. ISSN: 2088-8694
IJPEDS Vol. 8, No. 3, September 2017 : 979 – 989
988
Figure 16. The waveform of the injected active and reactive power in the grid with active power step
Figure 17. The waveform of the currents with active power step
Figure 18. Phase grid voltage and grid currents (UPF) with active power step
7. CONCLUSION
In this paper, we have introduced an improved DPC strategy for three phase voltage source inverter
in grid connected photovoltaic systems based on intelligent techniques. This technique of control is simulated
using the Matlab/Simulink environment. The main objectives of the proposed control are to reduce the
ripples of the active and reactive power, maintain these powers at the required level as well as it guarantees
sinusoidal currents with low THD. The simulation results obtained have attested good static, dynamic
performances and excellent robustness of this advanced control scheme in steady and transient state.
11. IJPEDS ISSN: 2088-8694
Advanced Direct Power Control for Grid-Connected Distribution Generation System .... (Mustapha Jamma)
989
REFERENCES
[1] Y. Atia and M. M. Salem, “Novel deadbeat power control strategy for grid connected systems,” J. Electr. Syst. Inf.
Technol., vol/issue: 2(2), pp. 242–256, 2015.
[2] F. Blaabjerg, et al., “Overview of Control and Grid Synchronization for Distributed Power Generation Systems,”
IEEE Trans. Ind. Electron., vol/issue: 53(5), pp. 1398–1409, 2006.
[3] M. G. Molina and P. E. Mercado, “Modeling and control of grid-connected photovoltaic energy conversion system
used as a dispersed generator,” in Transmission and Distribution Conference and Exposition: Latin America, 2008
IEEE/PES, pp. 1–8, 2008.
[4] Syafaruddin, et al., “Polar coordinated fuzzy controller based real-time maximum-power point control of
photovoltaic system,” Renew. Energy, vol/issue: 34(12), pp. 2597–2606, 2009.
[5] D. Zhi, et al., “Improved Direct Power Control of Grid-Connected DC/AC Converters,” IEEE Trans. Power
Electron., vol/issue: 24(5), pp. 1280–1292, 2009.
[6] J. Hu and Z. Q. Zhu, “Investigation on Switching Patterns of Direct Power Control Strategies for Grid-Connected
DC–AC Converters Based on Power Variation Rates,” IEEE Trans. Power Electron., vol/issue: 26(12),
pp. 3582–3598, 2011.
[7] T. Noguchi, et al., “Direct power control of PWM converter without power-source voltage sensors,” Ind. Appl.
IEEE Trans. On, vol/issue: 34(3), pp. 473–479, 1998.
[8] C. Attaianese, et al., “Direct torque and flux control of induction motor drives,” in Power Electronics and Drive
Systems, Proceedings, International Conference on, vol. 2, pp. 642–648, 1997.
[9] M. Malinowski, et al., “A comparative study of control techniques for PWM rectifiers in AC adjustable speed
drives,” IEEE Trans. Power Electron., vol/issue: 18(6), pp. 1390–1396, 2003.
[10] M. Malinowski, et al., “Review and comparative study of control techniques for three-phase PWM rectifiers,”
Math. Comput. Simul., vol/issue: 63(3–5), pp. 349–361, 2003.
[11] B. Bouaziz, et al., “A Sliding Mode approach into Constant Switching Frequency Direct Power Control of a Grid
Connected Voltage Source Converter,” Int. J. Electr. Eng. Inform., vol/issue: 7(1), pp. 42–58, 2015.
[12] D. Lalili, et al., “Input output feedback linearization control and variable step size MPPT algorithm of a grid-
connected photovoltaic inverter,” Renew. Energy, vol/issue: 36(12), pp. 3282–3291, 2011.
[13] S. A. Larrinaga, et al., “Predictive control strategy for DC/AC converters based on direct power control,” IEEE
Trans. Ind. Electron., vol/issue: 54(3), pp. 1261–1271, 2007.
[14] H. R. Khoei and E. F. Shahraki, “Fuzzy Logic Based Direct Power Control of Induction Motor Drive,” Bulletin of
Electrical Engineering and Informatics, vol/issue: 5(3), pp. 296-306, 2016.
[15] A. Bouafia, et al., “Fuzzy-Logic-Based Switching State Selection for Direct Power Control of Three-Phase PWM
Rectifier,” IEEE Trans. Ind. Electron., vol/issue: 56(6), pp. 1984–1992, 2009.
[16] K. Chikh, et al., “Improved DTC Algorithms for Reducing Torque and Flux Ripples of PMSM Based on Fuzzy
Logic and PWM Techniques,” in MATLAB - A Fundamental Tool for Scientific Computing and Engineering
Applications – vol. 1, V. Katsikis, Ed. InTech, 2012.
[17] M. Barara, et al., “Advanced Control of Wind Electric Pumping System for Isolated Areas Application,” Int. J.
Power Electron. Drive Syst., vol/issue: 4(4), pp. 567, 2014.
[18] P. M. Menghal and A. J. Laxmi, “Neural network based dynamic simulation of induction motor drive,” in Power,
Energy and Control (ICPEC), 2013 International Conference on, pp. 566–571, 2013.
[19] R. T. S. Meziane and H. Benalla, “Direct torque control for induction motor using intelligent techniques,” J. Theor.
Appl. Inf. Technol., vol/issue: 3(3), pp. 35–44, 2007.
[20] X. Wu and L. Huang, “Direct torque control of three-level inverter using neural networks as switching vector
selector,” in Industry Applications Conference, 2001. Thirty-Sixth IAS Annual Meeting. Conference Record of the
2001 IEEE, vol. 2, pp. 939–944, 2001.
[21] D. O. Abdeslam, et al., “A Unified Artificial Neural Network Architecture for Active Power Filters,” IEEE Trans.
Ind. Electron., vol/issue: 54(1), pp. 61–76, 2007.