A Novel Efficient Model For The Power Flow Analysis Of Power Systems,
2015
TÜBİTAK
A Novel Efficient Model For The Power Flow Analysis Of Power Systems, Amir Safdarian, Mahmud Fotuhi Firuzabad, Farrokh Aminifar
Turkish Journal of Electrical Engineering and Computer Sciences
The overall system status calculated by power flow analysis is the most basic information used for all decisions taken by power system operators and planners. While conventional AC power flow solutions are computationally tractable, approximate DC models are employed in many applications, such as optimal power flow studies and unit commitment problems, mainly due to the linear nature of DC models. These models do not provide any information on the reactive power and voltage magnitude quantities and occasionally inaccurate results of the active power values. This paper presents an efficient power flow approach compromising both the conflicting aspects of speed …
Sensitivity Analysis And Optimum Design For The Stator Of Synchronous Reluctance Machines Using The Coupled Finite Element And Taguchi Methods, Hossein Azizi, Abolfazl Vahedi
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents an investigation of the effect and optimization of stator geometry design parameters on the performance of synchronous reluctance machines (SynRMs). The level of importance of the stator design variable on the characteristic of the SynRM is determined using both the Taguchi method and a parametric analysis. An optimum design parameter combination is obtained using sensitivity analysis along with signal-to-noise ratio results. The 2-dimensional finite element model (FEM) of a SynRM is used to perform a sensitivity analysis and construct a Taguchi design of the experiment. The FEM simulation results confirm that the performance of the SynRM can …
Investigation Of Respiratory And Heart Rate Variability In Hypertensive Patients,
2015
TÜBİTAK
Investigation Of Respiratory And Heart Rate Variability In Hypertensive Patients, Ramazan Aldemi̇r, Mahmut Tokmakçi
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, in order to examine the effect of respiration on heart rate variability (HRV), signal processing analyses were performed between the signal received from the periodic movement of the chest of respiration and the pulse plethysmograph (PPS) signal, providing the calculation of both the time and frequency behavior of HRV and also including pulse rate information at the same time. Respiration is used as the comparison parameter in both healthy subjects and in hypertensive patients, not only with the time and frequency components of the HRV, but also with the galvanic skin resistance simultaneously taken with body temperature …
A New Cascaded Multilevel Inverter With Series And Parallel Connection Ability Of Dc Voltage Sources,
2015
TÜBİTAK
A New Cascaded Multilevel Inverter With Series And Parallel Connection Ability Of Dc Voltage Sources, Ebrahim Babaei, Saeed Sheermohammadzadeh Gowgani, Mehran Sabahi
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a new multilevel inverter is proposed based on the connection of DC voltage sources in series and parallel. The proposed topology is composed of series basic units that consist of series and parallel connections of DC voltage sources. The values of the DC voltage sources differ from one unit to another. A new algorithm to determine the magnitude of the DC voltage sources of the proposed structure is presented. All of the related equations for the proposed multilevel inverter are extracted and the optimum structure from several points of view such as the maximum blocked voltage by …
A Hierarchic Approach Based On Swarm Intelligence To Solve The Traveling Salesman Problem,
2015
TÜBİTAK
A Hierarchic Approach Based On Swarm Intelligence To Solve The Traveling Salesman Problem, Mesut Gündüz, Mustafa Servet Kiran, Eren Özceylan
Turkish Journal of Electrical Engineering and Computer Sciences
The purpose of this paper is to present a new hierarchic method based on swarm intelligence algorithms for solving the well-known traveling salesman problem. The swarm intelligence algorithms implemented in this study are divided into 2 types: path construction-based and path improvement-based methods. The path construction-based method (ant colony optimization (ACO)) produces good solutions but takes more time to achieve a good solution, while the path improvement-based technique (artificial bee colony (ABC)) quickly produces results but does not achieve a good solution in a reasonable time. Therefore, a new hierarchic method, which consists of both ACO and ABC, is proposed …
Adaptive Network-Based Inference System Models On Multiband Patch Antenna Design,
2015
TÜBİTAK
Adaptive Network-Based Inference System Models On Multiband Patch Antenna Design, Erdem Demi̇rci̇oğlu, Murat Hüsnü Sazli, Orhan Şengül, Şehabeddi̇n Taha İmeci̇, Hakki Alparslan Ilgin
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, an adaptive network-based fuzzy inference system (ANFIS) for multiband microstrip patch antenna (MMPA) modeling is proposed. The MMPA includes a single patch with inverted L-shaped stubs on the edges. The antenna production process needs iterative runs of the electromagnetic (EM) simulator, fabricating and testing the simulated antenna to find the optimum geometry. Production processes (design, simulation, fabrication, and testing) and the cost computation time add to the overall manufacturing expenses. A computer-aided modeling approach using the ANFIS is developed and trained with data acquired from the EM simulators, Sonnet Suites and AWR AXIEM, and measurement data. The …
Enhancing Sliding Mode Control With Proportional Feedback And Feedforward: An Experimental Investigation On Speed Sensorless Control Of Pm Dc Motor Drives, Mehmet Dal
Turkish Journal of Electrical Engineering and Computer Sciences
This paper investigates the enhancement of sliding mode control (SMC) with the combined use of feedforward torque compensation and proportional error feedback control. The proposed enhancement is adapted to the control of permanent magnet (PM) DC motor drives by synthesis of the equivalent control equation augmented as proportional feedback and feedforward terms. A novel sliding function, introduced by utilizing the estimated load torque and the estimated rotor current, is examined and compared with another known sliding function obtained by nonideal differentiation of the estimated rotor speed. The significance of the proposed enhancements to SMC consists of the elimination of disturbance, …
Short-Term Load Forecasting Using Mixed Lazy Learning Method,
2015
TÜBİTAK
Short-Term Load Forecasting Using Mixed Lazy Learning Method, Seyed-Masoud Barakati, Ali Akbar Gharaveisi, Seyed-Mohammad Reza Rafiei
Turkish Journal of Electrical Engineering and Computer Sciences
A novel short-term load forecasting method based on the lazy learning (LL) algorithm is proposed. The LL algorithm's input data are electrical load information, daily electricity consumption patterns, and temperatures in a specified region. In order to verify the ability of the proposed method, a load forecasting problem, using the Pennsylvania-New Jersey-Maryland Interconnection electrical load data, is carried out. Three LL models are proposed: constant, linear, and mixed models. First, the performances of the 3 developed models are compared using the root mean square error technique. The best technique is then selected to compete with the state-of-the-art neural network (NN) …
Control Of Oxygen Excess Ratio In A Pem Fuel Cell System Using High-Order Sliding-Mode Controller And Observer,
2015
TÜBİTAK
Control Of Oxygen Excess Ratio In A Pem Fuel Cell System Using High-Order Sliding-Mode Controller And Observer, Seyed Mehdi Rakhtala, Abolfazl Ranjbar Noei, Reza Ghaderi, Elio Usai
Turkish Journal of Electrical Engineering and Computer Sciences
The main objective of this manuscript is to design a high-order sliding-mode observer to provide finite time estimation of unmeasurable states (x_4: oxygen mass, x_5: nitrogen mass) together with the oxygen excess ratio (ratio of the input oxygen flow to the reacted oxygen flow in the cathode). This is done by applying second-order sliding modes through either super twisting or suboptimal controllers to control the proton exchange membrane fuel cell's breathing. The estimated oxygen excess ratio is controlled in a closed-loop system using 2 distinct sliding-mode approaches: a cascaded super twisting controller and a single-loop suboptimal structure. Simulation results are …
A New Systematic And Flexible Method For Developing Hierarchical Decision-Making Models,
2015
TÜBİTAK
A New Systematic And Flexible Method For Developing Hierarchical Decision-Making Models, Ulaş Beldek, Mehmet Kemal Leblebi̇ci̇oğlu
Turkish Journal of Electrical Engineering and Computer Sciences
The common practice in multilevel decision-making (DM) systems is to achieve the final decision by going through a finite number of DM levels. In this study, a new multilevel DM model is proposed. This model is called the hierarchical DM (HDM) model and it is supposed to provide a flexible way of interaction and information flow between the consecutive levels that allows policy changes in DM procedures if necessary. In the model, in the early levels, there are primary agents that perform DM tasks. As the levels increase, the information associated with these agents is combined through suitable processes and …
A Robust Algorithm Based On A Failure-Sensitive Matrix For Fault Diagnosis Of Power Systems: An Application On Power Transformers, Yunus Bi̇çen, Faruk Aras
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a robust algorithm for fault diagnosis of power system equipment based on a failure-sensitive matrix (FSM) is presented. The FSM is a dynamic matrix structure updated by multiple measurements (online) and test results (offline) on the systems. The algorithm uses many different artificial intelligence and expert system methods for adaptively detecting the location of faults, emerging failures, and causes of failures. In this algorithm, all data obtained from the power transformer, which have various nonlinear input and output parameters, are processed using the parallel matrix structure of the FSM to reach a global solution quickly. The parameters …
Dynamic Modeling Of Modular Fuel Cell For Maximum Power Point Tracking And Torque Ripple Reduction In Direct Torque Control Of Induction Motor, Majid Valizadeh, Mohammad Reza Feyzi, Ebrahim Babaei, Mehran Sabahi
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a comprehensive dynamic model of a proton exchange membrane fuel cell (FC) based on the electrical empirical model. The presented model is useful for online control as well as having suitable accuracy. FC stacks produce a DC voltage with a ratio of 2:1 in output from no-load to full-load. In vehicles that are equipped with FCs, the output voltage of the FC is drastically changed because the power and torque of the vehicle change with the driving cycle. In order to improve the performance of the direct torque control of induction motors, the modular structure of a …
A New Heuristic Method To Solve Unit Commitment By Using A Time-Variant Acceleration Coefficients Particle Swarm Optimization Algorithm, Arsalan Najafi, Mohsen Farshad, Hamid Falaghi
Turkish Journal of Electrical Engineering and Computer Sciences
Unit commitment is one of the most important problems in power system operation. Because of the large amount of parameters and constraints, it contains a high level of complexity. In this paper a new method based on a time-variant acceleration coefficients particle swarm optimization algorithm has been proposed to solve the unit commitment problem. Integer coding (for satisfying minimum up/down constraints) and binary coding (for satisfying spinning reserve constraint) have been utilized in the proposed method. Simulations in the different cases have been done with different sizes. Numerical results have shown the superiority and better convergence of the proposed method …
Short-Term Load Forecasting Without Meteorological Data Using Ai-Based Structures,
2015
TÜBİTAK
Short-Term Load Forecasting Without Meteorological Data Using Ai-Based Structures, İdi̇l Işikli Esener, Tolga Yüksel, Mehmet Kurban
Turkish Journal of Electrical Engineering and Computer Sciences
STLF is used in making decisions about economical power generation capacity, fuel purchasing, safety assessment, and power system planning in order to have economical power conditions. In this study, Turkey's 24-hour-ahead load forecasting without meteorological data is studied. ANN, wavelet transform and ANN, wavelet transform and RBF NN, and EMD and RBF NN structures are used in STLF procedures. Local holidays' historical load data are changed into data with normal day characteristics, and the estimation results of these days are not included in error computation. To obtain more accurate results, a regulation on forecasted loads is proposed. Regulated and unregulated …
An Intelligence-Based Islanding Detection Method Using Dwt And Ann,
2015
TÜBİTAK
An Intelligence-Based Islanding Detection Method Using Dwt And Ann, Mehrdad Heidari, Ghodratollah Seifossadat, Morteza Razaz
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a new method based on artificial neural network (ANN) and discrete wavelet transform (DWT) is proposed for electrical islanding detection. Transient signals produced during an event are used in the proposed method. ANN is trained to classify the transient events as islanding and nonislanding. The required features for classifying are extracted through DWT of voltage and current transient signals. The proposed method is then simulated on a medium voltage distribution system of CIGRE with 2 kinds of DGs. Results show that this method can detect electrical islands more rapidly and accurately.
Epilepsy Diagnosis Using Artificial Neural Network Learned By Pso,
2015
TÜBİTAK
Epilepsy Diagnosis Using Artificial Neural Network Learned By Pso, Nesi̇be Yalçin, Gülay Tezel, Ci̇han Karakuzu
Turkish Journal of Electrical Engineering and Computer Sciences
Electroencephalogram (EEG) is used routinely for diagnosis of diseases occurring in the brain. It is a very useful clinical tool in the classification of epileptic seizures and the diagnosis of epilepsy. In this study, epilepsy diagnosis has been investigated using EEG records. For this purpose, an artificial neural network (ANN), widely used and known as an active classification technique, is applied. The particle swarm optimization (PSO) method, which does not need gradient calculation, derivative information, or any solution of differential equations, is preferred as the training algorithm for the ANN. A PSO-based neural network (PSONN) model is diversified according to …
Improving The Performance Of Primal--Dual Interior-Point Method In Inverse Conductivity Problems,
2015
TÜBİTAK
Improving The Performance Of Primal--Dual Interior-Point Method In Inverse Conductivity Problems, Ashkan Javaherian, Amir Movafeghi, Reza Faghihi, Effat Yahaghi
Turkish Journal of Electrical Engineering and Computer Sciences
This study improves the performance of primal--dual interior-point method in inverse conductivity problems via replacing the conventional, complicatedly calculated scalar regularization parameter with a diagonal matrix termed ``multi-regularization parameter matrix'' here. The solution of the PD--IPM depends considerably on the choice of the regularization parameter. Calculation of the optimal regularization parameter, which yields the most accurate solution, is not simple due to the long iterative nature of the algorithm. The objective optimization, which is implemented by minimizing error in the solutions over an extensive range of the regularization parameters, yields the most accurate solution that can be achieved, although this …
Continuous-Time Hopfield Neural Network-Based Optimized Solution To 2-Channel Allocation Problem,
2015
TÜBİTAK
Continuous-Time Hopfield Neural Network-Based Optimized Solution To 2-Channel Allocation Problem, Zekeri̇ya Uykan
Turkish Journal of Electrical Engineering and Computer Sciences
The channel allocation problem in cellular radio systems is NP-complete, and thus its general solution is not known for even the 2-channel case. It is well known that the link gain system matrix (or received-signal power system matrix) of the radio network is (and may be highly) asymmetric, and that as the Hopfield neural network is applied to optimization problems, its weight matrix should be symmetric. The main contribution of this paper is as follows: turning the channel allocation problem into a maxCut graph partitioning problem, we propose a simple and effective continuous-time Hopfield neural network-based solution by determining its …
Control Of Soil Moisture With Radio Frequency In A Photovoltaic-Powered Drip Irrigation System,
2015
TÜBİTAK
Control Of Soil Moisture With Radio Frequency In A Photovoltaic-Powered Drip Irrigation System, Mahi̇r Dursun, Semi̇h Özden
Turkish Journal of Electrical Engineering and Computer Sciences
Solar-powered irrigation systems are becoming increasingly widespread. However, the initial setup costs of these systems are very high. To reduce these costs, both the energy usage and the prevention of losses from irrigation systems are very important. In this study, a drip irrigation control system of 1000 dwarf cherry trees was controlled using soil moisture sensors in order to prevent excessive water consumption and energy losses in a solar-powered irrigation system. The control system comprises units that are energized with solar panels, and the flow of information is implemented via radio frequency. Thus, by removing the cables that create difficulties …
Type Iii Compensated Voltage Mode Line Feedforward Synchronously Rectified Boost Converter For Driving Class D Audio H-Bridge To Deliver 7 W Peak Power Into An 8 Omega Speaker, Yavuz Kiliç
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a circuit topology for a synchronously rectified boost converter aimed to act as a power supply for a Class D H-bridge that would deliver up to 7 W peak power into an 8 Omega speaker is presented. The design is implemented in a submicron BCD process technology. Some of the challenges in this design are as follows. The first challenge was to optimise the design such that it would not cause on-chip power dissipation levels that would go beyond acceptable levels for Wafer Level Chip Scale Package (WLCSP), which is a commonly used package for space constrained …
