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International Review of Automatic Control (Theory and Applications) - September  2012 (Vol. 5 N. 5) - Papers








International Review of Automatic Control - Papers


go to top  Control of a Wind Turbine Based on PMSG and Connected to the Grid
         by  A. Dahbi, M. Hachemi

          Vol. 5. n. 5, pp. 553-559


Abstract - This paper describes the operation and control of a variable-speed wind generator using the permanent magnet synchronous generator (PMSG). This generator is connected to the grid by means of fully controlled converters, which consists of a pulse width-modulation (PWM) rectifier, an intermediate DC circuit, and a PWM inverter. Two main objectives are analyzed, extracting maximum power from wind, and feeding the grid by high-power quality of electrical energy; for that we applied the strategies of maximum power point tracking (MPPT) with speed controller which allows the PMSG to operate at an optimal speed. For delivering power to the grid, DC-link voltage is controlled by inverter using pulse wave modulation (PWM) in a way to deliver only the active power into the grid, thus we have unit power factor. This paper shows the dynamic performance of the complete system by its simulation using Matlab Simulink.
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Keywords: Permanent-Magnet Synchronous Generator (PMSG), Maximum Power Point Tracking (MPPT) Control, Pulse Wave Modulation (PWM), Modelling.



go to top  Analysis & Design of Closed Loop Control Using PID to Enhance Voltage Stability for STATCOM
         by  D. V. V. V. CH. Mouli, K. Dhanvanthri

          Vol. 5. n. 5, pp. 560-566


Abstract - Static Synchronous Compensator simply termed as STATCOM is a device to supply (capacitive) or consume (inductive) reactive power by varying reactive current based on load conditions. When the load increased the voltage would reduce due to inductive current or vice versa. To make stable voltage at particular point irrespective of the load, closed loop control is fine compared to the open loop control. The voltage source inverter generally used to vary capacitance and current source inverter generally used to vary the inductance. In a closed loop, based on the error, modulation index or firing angle delay of inverter will be changed. The error is induced due to the system voltage variations. This paper presents the experiment results of how the firing angle corrects the system voltage by varying voltage source inverter output and how to make fine control algorithm using tuned proportional-integral-derivative control.
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Keywords: STATCOM, PID Control, Hand Tuning, Transfer Function, Modulation Index, Park’s Transformation.



go to top  Sliding Mode Controller Design Synchronized by PLL Application to Buck DC/DC Converter
         by  Bensaada Messaoud, Boudghene Stambouli Amine, Bekhti Mohammed, Nasri Boualem

          Vol. 5. n. 5, pp. 567-574


Abstract - The buck type DC-DC converters are used in applications where the required output voltage needed to be smaller than the source voltage. The control of this type DC-DC converters is more difficult than the buck type where the output voltage is smaller than the source voltage. This paper is a simple and systematic approaches to the design of sliding mode controller for buck DC-DC Converters. Various aspects of the design, including the practical problems and the proposed solutions, are detailed. However, these control strategies can't compensate for large load current and input voltage variations. In this paper, a new control strategy by compromising both schemes advantages and avoiding their drawbacks is proposed, analyzed and simulated.
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Keywords: Buck, DC/DC Converters, Sliding Mode Control.



go to top  Analysis of Lightning Surge Transference Through Three-Phase Step-Up Transformers
         by  Petar Sarajčev, Josip Vasilj, Ranko Goić

          Vol. 5. n. 5, pp. 575-583


Abstract - Analysis of transformer behavior due to different transient phenomena is of paramount importance, not only from the designer’s perspective, but also from the perspective of the system engineer. One of the situations, where the analysis of the transformer transient behavior is of importance, is the overvoltage protection selection for the generators connected through step-up transformers. It has been acknowledged that the accurate transformer modeling is very important when the transient being studied is dominated by the behavior of the transformer itself. However, frequently it is not possible to obtain the necessary data to compute the parameters needed for the particular transformer model, due to the fact that this data often depends on the transformer internal geometry, which is only available to the manufacturers and is considered proprietary information. This paper proposes one possible high-frequency transformer model, appropriate for the lightning surge transference analysis. Its performance will be analyzed by means of the comparison with the simpler analytical and numerical transformer models, derived for the same purpose and tested by the measurements carried-out on actual transformers.

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Keywords: Transformer Modeling, Step-Up Transformer, Lightning-Surge Transfer, Lumped-Parameter Model, Frequency-Dependence, Capacitance Network.



go to top  An Integrated Unbalance Compensation and Load Sharing Methods Using Inverter Based Distributed Generator
         by  H. Soleimani Bidgoli, S. V. Khatami, M. Abolhasani Zarjoo, M. Razmi

          Vol. 5. n. 5, pp. 584-592


Abstract - In this paper, a micro-grid that is feeding both three-phase and single phase loads is considered. Using, fuel cell four wire inverter as an unbalance current producer, load unbalanced viewed by rotary generator and unbalance voltage are compensated. Moreover, a load sharing control loop is integrated to the fuel cell inverter controller, in order to enhance the stabilization of system frequency and voltage during transient conditions. The feasibility of the proposed control strategy is demonstrated trough several conducted simulation case studies in PSCAD environment.
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Keywords: Micro Grid, Unbalance Compensation, Power Management.



go to top  Simulation and Control of Permanent Magnet Synchronous Generators Used in Wind Energy Conversion System
         by N. Lachguer, M. T. Lamchich

          Vol. 5. n. 5, pp. 593-598


Abstract - This paper presents the control strategy of permanent magnet synchronous generator (PMSG) used in wind energy conversion system, whose the PMSG stator is connected to the grid side through the back-to-back PWM converter an intermediate dc circuit. In this configuration, the control of the generator side converter can realize the maximal energy capture in variable wind speed, and the grid side converter controls the dc link and the power factor of line side. In attempt to mitigate the current harmonics injected into the grid, an LCL filter is inserted between the inverter and the grid. Simulation results of the system using the blocs Power System Blockset of Matlab /Simulink are illustrated to verify the effectiveness of this control strategy.

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Keywords: Permanent Magnet Synchronous Generators (PMSG), Wind Energy Conversion System (WECS), bock-to-back PWM Converter, LCL Filter.



go to top  Performance Evaluation of IPFC Using Fuzzy Logic Controller for Power System Stabilization
         by M. Moudjahed, M. Boudiaf

          Vol. 5. n. 5, pp. 599-605


Abstract - This paper presents the effect of Interline Power Flow Controller (IPFC) using a combination of a fuzzy logic controller (FLC) and a proportional Integral (PI) controller on damping transient oscillations of a multi-machine power system. The proposed approach is compared to the conventional regulation using an automatic voltage regulation (AVR) and speed governor to evaluate its performance. IPFC is modeled as an ideal series voltage source (master) with an ideal series voltage source (slave). The proposed method is tested on the disturbed Western Systems Council Coordinating (WSCC) 3 machine-9 bus system. The results are presented and discussed.

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Keywords: FACTS, UPFC, IPFC, SSSC, Fuzzy Logic Controller, Power System Stability.



go to top  A New Control Approach to Variable Speed PM Wind Generator for Enhancing Dynamic Stability of Wind Farm
         by  Marwan Rosyadi, S. M. Muyeen, Rion Takahashi, Junji Tamura

          Vol. 5. n. 5, pp. 606-616


Abstract - In this paper a new control scheme for variable speed permanent magnet wind generator connected to grid through LC filter is proposed in order to enhance stability of wind farms including fixed speed induction generators. Design and control approaches of two level back to back converters are developed in order for both active and reactive powers delivered to a power grid system to be controlled effectively. The stability perfor¬mances of the controller system such as characteristic of dynamic response and good margin are also investigated based on the bode diagram. To eva¬luate the controller system capabili¬ties, simula¬tion analyses for both transient and steady state conditions are per¬formed on a model system com¬posed of two wind farms connec¬ted to an infinite bus. The simula¬tions have been performed using PSCAD/EMTDC. The results show that the proposed controller is highly effective to augment voltage stability of the wind farm.
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Keywords: Variable Speed Wind Turbine, Permanent Magnet Synchronous Generator, Back To Back Converter, Voltage Stability, LC Filter.



go to top  Study and Simulation of Damping the Low Frequency Oscillations Based on Takagi-Sugeno Fuzzy Controller
         by  Majid Aryanezhad, Mohsen Saniei, Elahe Ostadaghaee

          Vol. 5. n. 5, pp. 617-623


Abstract - Oscillations of small magnitude and low frequency between 0.1 to 2.5 Hz often persist for long periods of time and some cases can hinder power transfer capability. Power System Stabilizers (PSS) are added to excitation system to improve the dynamic response and provide damping the low frequency oscillations. The conventional PSS (CPSS) which is used lead-lag compensation is resulting into poor performances under different loading conditions as the parameters setting are designed for specific operating conditions. This paper presents a new type of Fuzzy Logic Power System Stabilizer (FLPSS) in a Single Machine connected to Infinite Bus (SMIB).The generator is represented by the Phillips-Heffron model. In order to accomplish the stability enhancement, a Takagi-Sugeno fuzzy controller proposed with speed deviation (Δω) and acceleration (Δὼ) of the rotor of synchronous generator were taken as the inputs of fuzzy logic controller. The performance of the FLPSS is compared with Conventional Power System Stabilizer (CPSS) and without PSS (NOPSS). Simulation studies have been carried out using MATLAB SIMULINK. The simulation results demonstrated that the proposed FLPSS control scheme performs well and strongly control the power system under different changes in inputs.
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Keywords: Power System Stabilizer, Fuzzy Logic, Low Frequency Oscillations, Phillips-Heffron Model.



go to top  Swarm-based Approach to Path Planning Using Honey Bees Mating Algorithm and Adaptive Resonance Theory (ART1)
         by  Petar Curkovic, Bojan Jerbic, Tomislav Stipancic

          Vol. 5. n. 5, pp. 624-629


Abstract - In this paper, we propose a novel trajectory planning method for a robot navigating in the workspace containing arbitrarily distributed obstacles. To generate the robot’s trajectory, we developed an algorithm based on swarm intelligence concepts, to search valid and optimized trajectories in task space. The trajectories are optimized in terms of minimizing collisions and the total time elapsed. Additionally, we implement self-organizing neural architecture to robots’ controller. Using ART neural network of type 1, the robot is able to explore the environment and learn continuously.
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Keywords: Path Planning, Swarm Intelligence, Mobile Robot, Self Organization.



go to top  An Experiment-based Approach for Improving the Photovoltaic Power Supply System Performance by Matching Impedance
         by  M. Kamta, A. Dandoussou

          Vol. 5. n. 5, pp. 630-637


Abstract - This paper presents an experiment-based approach for choosing and designing a suitable maximum power point tracking system for a photovoltaic generator. This approach consists of the determination of load parameters by fitting a theoretical function to experimental points which have been recorded during cloudy days in Ngaoundere, Cameroon. The P-V curves of both photovoltaic generator and active load are plotted, taking into account the effects of irradiance, cell temperature and series resistance. The intersection points of these curves are the operating points of photovoltaic generator. Regarding the positions of these operating points in comparison to the maximum power points on the P-V curves, an appropriate converter topology can be chosen among the different converter topologies, i.e.: buck, boost, or buck-boost. Simulation results showed that the best is the choice of the converter topology, the higher is the photovoltaic power supply system performance.
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Keywords: Photovoltaic Generator, DC/DC Converter, MPPT, Matlab/Simulink.



go to top  Unbalance Sources Identification in Non-Sinusoidal Electric Power Systems
         by  Reyes S. Herrera, Jesús R. Vázquez

          Vol. 5. n. 5, pp. 638-645


Abstract - Voltage unbalance is one of the main problems in electric distribution system. The Standards limit the level of voltage unbalance in a specific point without considering its origin. Nevertheless, it may be important in different aspects. For example, to establish the most suitable procedure to mitigate the voltage and/or current unbalance or to identify the responsible agents for the system unbalance. To do that, a new index, denominated unbalance current ratio, is proposed in this paper. It is based on decomposing the actual current at the input of the load in three components: the first one is the required by an unbalanced linear load, the second one is the required by a balanced non-linear load and the third one corresponds to a balanced linear load. All of them compose the total current at the input of the analyzed load. The new index can be calculated from only the measurement of the current at the input of the load and the voltage at the point of common connection. Several simulation systems have been considered to check the index behavior and an experimental platform has been designed to verify its validity in unbalanced non-sinusoidal systems.
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Keywords: Distribution Systems, Power Quality, Unbalance, Harmonic Distortion.



go to top  Numerical Treatment of Singularly Perturbed Singular Two-Point Boundary Value Problem Using Non - polynomial Spline  in Optimal Control Problems
         by  K. Phaneendra, Y. N. Reddy, E. Siva Prasad

          Vol. 5. n. 5, pp. 646-651


Abstract - In this paper, a numerical solution for a class of singularly perturbed singular two-point boundary value problems in optimal control problems was presented on a uniform mesh by using non-polynomial spline function. Here, one singularity is the perturbation parameter and the other singularity is the point zero at which the coefficient function of the first derivative is not analytic. At the singularity zero the boundary value problem is modified and using it, the tridiagonal scheme obtained by the method is solved efficiently using discrete invariant imbedding. This method is very easy to implement. Numerical results are presented to illustrate the proposed method and compared with exact solution.
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Keywords: Singularly Perturbed Singular Boundary Value Problem, Singular Point, Non-Polynomial Spline, Boundary Layer.



go to top  Boundary Flux Reconstruction for Semilinear Parabolic Systems: Hum Approach
         by  A. Boutoulout, H. Bourray, F.Z. El Alaoui

          Vol. 5. n. 5, pp. 652-659


Abstract - This paper is devoted to extend the notion of regional gradient observability of a distributed parameter system governed by semilinear parabolic equations to boundary case. This original concept consists in studying the gradient observability of such a system only on a subregion Г of the boundary of the system evolution domain ∂Ω. We give definition and some properties of this notion and we show that under some hypothesis, the regional boundary gradient observability is guaranted. We show by means of Hilbert Uniqueness Method (HUM) combined with fixed point techniques that it is possible to reconstruct such a gradient on a desired subregion Γ. This approach leads to interesting results which are performed through numerical example and simulations
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Keywords: Distributed Systems - Semilinear Parabolic Systems - Boundary Gradient Reconstruction - Regional Boundary Observability - Fixed Point- Hilbert Uniqueness Method (HUM).



go to top  Improvement Control Power of Photovoltaic System Connected to the Grid
         by  F. Bouchafaa

          Vol. 5. n. 5, pp. 660-666


Abstract - This paper presents a simulation model of the electric part of a grid connected photovoltaic generation system. The model contains a detailed representation of the main components of the system that are the solar array, and the grid side inverter multilevel inverter NPC VSI. In order to extract the maximum amount of from the photovoltaic generator, we propose an intelligent control method for the maximum power point tracking (MPPT) of a photovoltaic system under variable temperature and insulation conditions. This method uses a fuzzy logic controller. As part of our work, we will focus on voltage inverter at three levels to NPC structure. The latter can increase the voltage supplied to the load (network) through their topology. Thus, they can generate more voltage sinusoidal possible and improve the total harmonic distortion through the high voltage levels provided by the structure of this new converter. The grid interface inverter transfers the energy drawn from the PV module into the grid by keeping common dc voltage constant. The PQ control approach has been presented for the multilevel inverter. The simulation results under Matlab/Simulink show the control performance and dynamic behaviour of grid connected photovoltaic system.
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Keywords: PV, MPPT, Fuzzy Logic Control, NPC Inverter, Enslavement, Power, Grid-Connected Photovoltaic System.



go to top  Neuro-Fuzzy Predictive Control
         by  Jana Paulusová, Mária Dúbravská

          Vol. 5. n. 5, pp. 667-672


Abstract - In this paper neuro-fuzzy predictive controller for nonlinear system is addressed, proposed and tested. The proposed neuro-fuzzy convolution model consists of a steady-state neuro-fuzzy model and a gain independent impulse response model. The proposed model is tested in model based predictive control of the concentration in the chemical reactor, manipulating its flow rate. The paper deals with theoretical and practical methodology, offering approach for intelligent neuro-fuzzy control design and its successful application.
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Keywords: ANFIS, Fuzzy Models, Neuro-Fuzzy, Predictive Control.



go to top  Precision Speed Control of DC Motor Drive System
         by  Hussein S. Sarhan, Rateb H. Issa, Mohammad A. Alia, Ibrahim K. Al-Abbas

          Vol. 5. n. 5, pp. 673-676


Abstract - DC motors have been widely used in industrial applications, requiring precision control of the motor speed and fast dynamic response. Phase-locked techniques are well suited to provide this control by phase locking the motor to a stable and accurate reference frequency. In this paper, a MOSFET-DC motor speed control system using PIC microcontroller, in which all digital loop principle is applied to precisely make the motor speed locked onto a reference frequency. Simulation and experimental results of the proposed system show that motor speed practically is not affected by load variations, and the time response of motor speed is fast and acceptable. The achieved speed regulation is 0.08-0.5%.
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Keywords: DC Motor, Precision Speed Control, Phase-Locked Loop, PIC Microcontroller.



go to top  Review of Corrective Switching and Corrective FACTS Controls for Use in Power Transmission Systems
         by  A. Obok Opok, K. A. Folly

          Vol. 5. n. 5, pp. 677-688


Abstract - The paper presents a review a number of publications on the use of corrective switching and FACTS control actions, as well as their practical applications.The review take into account the purpose of corrective switching and corrective FACTS control, switching elements and models, approaches to corrective switching and FACTS control. The review is organized into the following groups: line and bus bar switching, corrective switching algorithms, corrective switching and security, flexible transmission topology, and corrective FACTS control. Originally corrective switching was used forrelieve of branch overloads and bus voltage violations. However the advent and adoption of FACTS devices in transmission systems to control active and reactive power flows has added extra aspect for relieve of branch overloads and mitigation of bus voltage violations. It is demonstrated by recent research that economic efficiency can be realized in the transmission system through network topology changes by switching of lines in a systematic way. The aims of the review are: (i) to fill a gap on literature review on corrective switching and corrective FACTs control (ii) to identify new opportunities and developments for researchers on the subject and (iii) to highlight new trends and state of developments in that area with regard to application.
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Keywords: Transmission Switching, FACTS Control, Network Topology.



go to top  Cardiac Arrhythmias Detection by Neural Networks: VHDL Modeling and Synthesis on FPGA
         by  Z. Chalabi, D. Chalabi, A. Amara, N. Berrached

          Vol. 5. n. 5, pp. 689-694


Abstract - Electrocardiogram ECG reflects the heart's electrical activity. Any morphological or time modification of the signal may indicate pathology. This paper presents software and hardware implementation of an ECG signals classifier by the neural network, the multilayer perceptron (MLP), to diagnose cardiac arrhythmias. The first, software, aims to train and optimize the PML. The second, hardware, is to have a low power consumption and less expensive classifier. It is performed on the FPGA based VHDL description language using the development card, Cyclone II. The program is compiled and simulated in the Altera Quartus II software. MIT-BIH 'Arrhythmia Database has been used for training and validating of the PML classifier. The obtained results, by both techniques, are quite similar and are very satisfactory.
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Keywords: Characteristics Extraction, ECG, FPGA, Neuronal Classification, R Peaks Detection, PML, VHDL.



go to top  Self-Tuning-Parameter Fuzzy PID Speed Controller Performance in an Electro-Hydraulic Forklift with Different Rule Sets
         by  Tatiana A. Minav, Lasse I. E. Laurila, Juha J. Pyrhönen

          Vol. 5. n. 5, pp. 695-702


Abstract - The purpose of this study is to evaluate the performance of an electro-hydraulic forklift system with a different number of fuzzy rules in its self-tuning-parameter fuzzy PID speed controller. The drive consists of a direct-torque-controlled (DTC) electric servo motor directly running a reversible hydraulic pump. A self-tuning-parameter fuzzy PID controller is designed to control the rotational speed of a permanent magnet synchronous machine (PMSM). Simulation of an electro-hydraulic system of a working machine is carried out by a Matlab Simulink model. Analysis and verification of the practical results are performed. Comparisons are made with a different number of fuzzy rules.
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Keywords: Permanent Magnet Machines, Energy Efficiency, Energy Recovery, Forklift, Electric Servo Drive, Hydraulics, Self-Tuning-Parameter Fuzzy PID, Speed Control.



go to top  Discrete-Time Variable Structure Controller Synthesis Using Model in Canonical Subspace
         by  Olivera Iskrenovic-Momcilovic

          Vol. 5. n. 5, pp. 703-709


Abstract - Analyzed in this paper is the variable structure system (VSS) to control the n-th order object. First, a discrete mathematical model of the system over the canonical space, using the Euler method, was given for the discussed VSS system. Then, decomposition of the canonical space to subspaces with and without control by introducing the output variable differential was carried out. Finally, based on the quasi-sliding (zigzag) mode existence conditions, relations to provide this mode over the canonical subspace with control is derived. One illustrative example is used to demonstrate the discrete-time variable structure (DTVS) controller synthesis procedure over the canonical subspace.
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Keywords: Discrete-Time Systems, Variable Structure System, Sliding Mode Control, Euler Method, Canonical Subspace.



go to top  Estimation of Electrical Characteristics in Equivalent Circuit Model of Non-ideal Potential Transformer
         by  Mamdouh M. Halawa

          Vol. 5. n. 5, pp. 710-715


Abstract - In this paper equivalent circuit model of a non-ideal potential transformer (PT) with the model parameters determined practically using open-circuit and short-circuit tests. The experimental setup for determining the equivalent circuit parameters is presented. As an example of the usefulness of the non-ideal equivalent circuit of the PT, the parameters evaluated in the lab are used to calculate two important transformer characteristic; percentage regulation and maximum efficiency. The equivalent circuit of the tested transformer is also simulated using the LTspice/SwCAD III simulator to study some electrical characteristics of the PT. For instance, the frequency behavior of some parameters in the equivalent circuit is investigated accordingly. The parameters behaviors at frequencies up to 100 Hz, such as copper loss, iron loss, series impedance and shunt impedance, has been indicated in this paper.
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Keywords: Potential Transformers, Equivalent Circuit Model, Parametric Identification, Electrical Simulation, Transformer Characteristics.



go to top  A New MOSFET based Solar Charge Controller for Battery Charger Applications
         by  Rahul Gogia, Umashankar S.

          Vol. 5. n. 5, pp. 716-720


Abstract - A charge controller is a power electronic device used in medium voltage and medium power applications. This paper proposes a topology for a solar charge controller to regulate the power flowing from a photovoltaic panel into a rechargeable battery while also preventing periodic overcharging and is characterized by analog simplicity, high efficiency and reliability in design. This design also provides larger load current and faster charging of the batteries with the usage of power MOSFET’s. The controller design has been modeled and simulated in multi-sim software and then constructed in hardware to validate the results. It signifies the importance of developing devices that will harness renewable sources of energy in an era of increasing consumer demands for power and decreasing conventional sources of energy.
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Keywords: Charge Controller, Multi-Sim, Power MOSFET’s, Regulate Power.



go to top  Comparative Analysis between Fuzzy and Neural State Observation Approach of Nonlinear Systems Application to Induction Motors
         by A. N. Lakhal, A. S. Tlili, N. Benhadj Braiek

          Vol. 5. n. 5, pp. 720-727


Abstract - This paper deals with comparative analysis between two non conventional state observation methods. These are the fuzzy and the neural state observation approaches. The Takagi-Sugeno fuzzy state observer (T-S) is designed by applying the PDC concept (Parallel Distributed Compensation) which local models and local observers share the same fuzzy rules. The stability study of such observer, based on the use of a fuzzy non-quadratic Lyapunov function, led to the development of conditions of stability formulated as linear matrix inequalities (LMIs) for the calculation of gains of local observers to design non linear fuzzy observer. As for the neural state observer, it is based in one hand on neural identification of the non-linear system, and in the other hand on a pole placement technique for calculating the gains of state observation. For neural identification, we use a neural network with non linear parameters (RNPNL). This RNPNL is a multilayer feedforward neural network using the sigmoïdal activation function and the modified error backpropagation learning algorithm. The proposed state observation techniques are applied to the nonlinear model of the induction motor to reconstruct the non-measurable state variables and in particular the rotor flux.
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Keywords: Takagi-Sugeno Fuzzy State Observer, Neural State Observer, Non Quadratic Lyapunov Function, LMIs, Induction Motor.