Minimum Number Of Permanent-Magnet Synchronous Generators For Coordinated Low-Voltage Ride-Through Of Induction Generators In Hybrid Wind Farms, Shenghu Li, Rui An
Turkish Journal of Electrical Engineering and Computer Sciences
Coordinated low-voltage ride-through (LVRT) of induction generators (IGs) utilizing the excessive reactive power of permanent magnet synchronous generators (PMSGs) in hybrid wind farms is attractive due to saving investments on shunt compensators. The existing research is mainly based on dynamic simulations to given scenarios and does not quantify the necessary capacity and number of PMSGs. This paper newly proposes an analytical model to quantify the minimum number of the PMSGs for coordinated LVRT. The critical voltage at the point of common coupling (PCC) leading to slip instability of the IGs is quantified. To avoid instability, necessary var support from the …
Power Quality Assessment In Different Wind Power Plant Models,
2016
TÜBİTAK
Power Quality Assessment In Different Wind Power Plant Models, Hamid Shariatpanah, Morteza Sabouri Kenari, Roohollah Fadaeinedjad
Turkish Journal of Electrical Engineering and Computer Sciences
In order to fully study the power quality of a grid-connected wind farm, a suitable model providing accurate output for wind farms is necessary. In this paper, different methods, which have been proposed in previous studies, are investigated with regard to the power quality problem using a squirrel-cage induction generator wind turbine. These models are different in terms of accuracy and simulation time. The question is: which method is more suitable for simulation of a wind farm? To answer this question, a criterion should be introduced to compare different modeling methods. Full turbine representation is introduced as the best criterion …
Fpga Implementations Of Scale-Invariant Models Of Neural Networks,
2016
TÜBİTAK
Fpga Implementations Of Scale-Invariant Models Of Neural Networks, Zeinulla Zhanabaev, Yeldos Kozhagulov, Dauren Zhexebay
Turkish Journal of Electrical Engineering and Computer Sciences
Integrated circuit implementations of new models of neural networks with scale-invariant properties are presented. The specifics of such models are necessary in analysis of discrete mappings containing fractional power. We suggest an algorithm for increasing the power of a physical value by using a field-programmable gate array (FPGA). Comparisons between FPGA implementations and numerical results are demonstrated.
Video Temporal Error Concealment Using Improved Directional Boundary Matching Algorithm,
2016
TÜBİTAK
Video Temporal Error Concealment Using Improved Directional Boundary Matching Algorithm, Seyed Mojtaba Marvasti-Zadeh, Hossein Ghanei-Yakhdan
Turkish Journal of Electrical Engineering and Computer Sciences
Nowadays some systems such as multimedia systems try to present a high quality of digital videos every day. Because of the possible errors in communication channels, compressed video data would be damaged in the sending process. Error concealment is a useful technique for concealing the effects of sending errors at the decoder. In this paper, an improved directional boundary matching algorithm is presented, in which by using adjacent macroblocks (MBs) of the damaged MB a direction is identified for each boundary. Then every boundary of candidate MBs is compared to an identified direction. Finally, the candidate motion vector (MV) that …
Thermal Aging Of Solid Insulation Under Dual Temperature Variation,
2016
TÜBİTAK
Thermal Aging Of Solid Insulation Under Dual Temperature Variation, Amit Kumar Mehta, Ram Naresh Sharma, Sushil Chauhan
Turkish Journal of Electrical Engineering and Computer Sciences
The power transformer is one of the most expensive pieces of equipment in a high-voltage AC power system. An adequate monitoring system for power transformers can help in reducing the failure rate and thereby enhance system reliability and economic efficiency. Long-term and accelerated aging is not possible in real transformers, so prorated models of real transformers are preferred. This paper presents a study aimed at the aging of different cellulose papers and pressboards impregnated with transformer oil subjected to accelerated thermal aging at an oil temperature of 120 $^{\circ}$C and winding temperature of 150 $^{\circ}$C for time intervals extending from …
Stochastic Congestion Management Considering Power System Uncertainties: A Chance-Constrained Programming Approach,
2016
TÜBİTAK
Stochastic Congestion Management Considering Power System Uncertainties: A Chance-Constrained Programming Approach, Mehrdad Hojjat, Mohammad Hossein Javidi, Dariush Yazdanpanah
Turkish Journal of Electrical Engineering and Computer Sciences
Considering system uncertainties in developing power systems, algorithms such as congestion management (CM) are vital in power system analysis and studies. This paper proposes a new model for power system CM by considering power system uncertainties based on chance-constrained programming (CCP). In the proposed approach, transmission constraints are taken into account by stochastic, instead of deterministic, models. The proposed approach considers network uncertainties with a specific level of probability in the optimization process, and then an analytical approach is used to solve the new model of stochastic congestion management. In this approach, the stochastic optimization problem is transformed into an …
Behavior Learning Of A Memristor-Based Chaotic Circuit By Extreme Learning Machines,
2016
TÜBİTAK
Behavior Learning Of A Memristor-Based Chaotic Circuit By Extreme Learning Machines, Ayşegül Uçar, Emrehan Yavşan
Turkish Journal of Electrical Engineering and Computer Sciences
As the behavior of a chaotic Chua's circuit is nonstationary and inherently noisy, it is regarded as one of the most challenging applications. One of the fundamental problems in the prediction of the behavior of a chaotic Chua's circuit is to model the circuit with high accuracy. The current paper presents a novel method based on multiple extreme learning machine (ELM) models to learn the chaotic behavior of the four elements canonical Chua's circuit containing a memristor instead of a nonlinear resistor only by using the state variables as the input. In the proposed method four ELM models are used …
A New Algorithm Of Parameter Estimation Of A Photovoltaic Solar Panel,
2016
TÜBİTAK
A New Algorithm Of Parameter Estimation Of A Photovoltaic Solar Panel, Mustapha Belarbi, Kamel Haddouche, El-Habib Belarbi, Amine Boudghene-Stambouli
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, we present a new approach for estimating the one-diode model parameters of a photovoltaic solar panel according to the irradiance and temperature. These parameters are given, at a known irradiance and temperature, from the knowledge of three operating points: short circuit, open circuit, and maximum power. In the first step, the adopted approach concerns the resolution of the system of equations constituting the three operating points to write all the model parameters according to series resistance. Secondly, we make an iterative resolution at the optimal operating point by using the Newton--Raphson method to calculate the series resistance …
Optimal Power Flow With Svc Devices By Using The Artificial Bee Colony Algorithm,
2016
TÜBİTAK
Optimal Power Flow With Svc Devices By Using The Artificial Bee Colony Algorithm, Kadi̇r Abaci, Volkan Yamaçli, Ali̇ Akdağli
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper a simple and efficient heuristic search method based on the artificial bee colony (ABC) algorithm is presented and used for the optimal power flow (OPF) problem in power systems with static VAR compensator (SVC) devices. The total generation cost of a power system with SVC devices (which improve the voltage stability at load buses) is optimally minimized with the use of ABC. The ABC, which is based on the foraging behavior of honey bees searching for the best food source, is a recently proposed optimization algorithm. The performance of the presented ABC algorithm was tested and verified …
Extracting The Region Of Interest From Mfl Signals,
2016
TÜBİTAK
Extracting The Region Of Interest From Mfl Signals, Ali Sadr, Raziyeh Sadat Okhovat
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, we study the magnetic flux leakage (MFL) signals for detection of defects in ferromagnetic materials. MFL signals consist of a background that is not constant and is combined with noise. Since there are slight variations because of noise, any large distortion shows a defect. Here the estimation of the background and then the determination of a threshold to distinguish defects from noise have been used for locating defects. In this method, precise evaluation of these two parameters has a vital role on the defect detection. The concept of histograms has been employed for eliminating the effect of …
An Alternative Carry-Save Arithmetic For New Generation Field Programmable Gate Arrays,
2016
TÜBİTAK
An Alternative Carry-Save Arithmetic For New Generation Field Programmable Gate Arrays, Uğur Çi̇ni̇, Mustafa Aktan, Avni̇ Morgül
Turkish Journal of Electrical Engineering and Computer Sciences
In this work, a double carry-save addition operation is proposed, which is efficiently synthesized for 6-input LUT-based field programmable gate arrays (FPGAs). The proposed arithmetic operation is based on redundant number representation and provides carry propagation-free addition. Using the proposed arithmetic operation, a compact and fast multiply and accumulate unit is designed. To our knowledge, the proposed design provides the fastest multiply-add operation for 6-input LUT-based FPGA systems. A finite impulse response filter implementation is given to show the performance of the proposed structure. The proposed implementation provides a dramatic performance increase, which is at least 2 times faster than …
Incremental Weighted Bipartite Algorithm For Large-Scale Recommendation Systems,
2016
TÜBİTAK
Incremental Weighted Bipartite Algorithm For Large-Scale Recommendation Systems, Haihong E, Jianfeng Wang, Meina Song, Qiang Bi, Yingyi Liu
Turkish Journal of Electrical Engineering and Computer Sciences
Personalized recommendation systems are a solution for information overload. In the real recommendation system, the data are dynamic; thus, the real time of the system will be seriously affected if we recalculate after every change, and, in time, sensitive situation of the delayed updated calculation will affect the accuracy of the recommendation. The incremental calculation methods of collaborative filtering, clustering, singular value decomposition, and bipartite algorithm have achieved some progress; however, there is limited research on the incremental computation of the weighted bipartite algorithm. This paper proposes a personalized recommendation algorithm. In this algorithm, the rank of the recommendations is …
An Improved Real-Time Adaptive Kalman Filter With Recursive Noise Covariance Updating Rules,
2016
TÜBİTAK
An Improved Real-Time Adaptive Kalman Filter With Recursive Noise Covariance Updating Rules, Iyad Hashlamon, Kemaletti̇n Erbatur
Turkish Journal of Electrical Engineering and Computer Sciences
The Kalman filter (KF) is used extensively for state estimation. Among its requirements are the process and observation noise covariances, which are unknown or partially known in real-life applications. Uncertain and biased values of the covariances result in KF performance degradation or divergence. Unlike previous methods, we are using the idea of the recursive estimation of the KF to develop two recursive updating rules for the process and observation covariances, respectively designed based on the covariance matching principles. Each rule has a tuning parameter that enhances its flexibility for noise adaptation. The proposed adaptive Kalman filter (AKF) proves itself to …
Modified Hexagonal Sierpinski Gasket-Based Antenna Design With Multiband And Miniaturized Characteristics For Uwb Wireless Communication, Ademola Aluwaseun Kaka, Mehmet Toycan
Turkish Journal of Electrical Engineering and Computer Sciences
A modified hexagonal Sierpinski gasket-based fractal antenna is proposed for ultrawide-band (UWB) wireless applications. The designed antenna has miniaturized (36 $\times $ 48 mm$^{2})$ and multiband characteristics. Two design guidelines, the partial ground plane technique and the circular annular ring patch on the substrate, are applied to improve impedance matching and radiation pattern characteristics. According to the simulation results, the proposed modified antenna has a reflection coefficient $S_{11} $ of less than --15 dB, a linear phase of the reflection coefficient, 80{\%} radiation efficiency, 2--4.5 dBi antenna gain, and omnidirectional radiation pattern properties over the full UWB spectrum (3.1--10.6 GHz). …
Research On Switched Reluctance Machine Drive Topology And Control Strategies For Electric Vehicles,
2016
TÜBİTAK
Research On Switched Reluctance Machine Drive Topology And Control Strategies For Electric Vehicles, He Cheng, Hao Chen, Lei Ma, Guojun Yu
Turkish Journal of Electrical Engineering and Computer Sciences
The electric drive system is one of the key technologies for electric vehicles. First, the energy flow of an electric vehicle is analyzed in the driving, braking, and charging working states. After that, a drive topology that can achieve 3 working states is proposed based on the driving characteristics of a switched reluctance machine. In the driving state, the boost mode of a front-end converter is used to achieve different operating conditions, including low speed with a light load or high speed with a heavy load. In the braking state, the front-end converter is used to implement smooth switching between …
Sensorless Velocity And Direction Angle Control Of An Unmanned Vehicle,
2016
TÜBİTAK
Sensorless Velocity And Direction Angle Control Of An Unmanned Vehicle, Adnan Derdi̇yok, Abdullah Başçi̇
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper an observer based on measured and estimated currents and a kinematic model is designed to estimate the velocity and direction angle of an unmanned vehicle (UV). The Lyapunov stability theory is used to establish the stability conditions for the observer. It is shown that the observer will converge in a finite time and the observer gains satisfy the constraints of the stability conditions. The observed velocity and direction angle are used in the closed loop instead of measured ones for sensorless control of the UV. The velocity and direction angle control of the UV are carried out …
A 2.4-Ghz Highly Linear Derivative Superposition Gilbert Cell Mixer,
2016
TÜBİTAK
A 2.4-Ghz Highly Linear Derivative Superposition Gilbert Cell Mixer, Samaneh Sedighi, Omid Hashemipour, Massoud Dousti
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a new derivative superposition Gilbert cell to minimize the third-order nonlinear current term of transconductance transistors. To decrease the parasitic capacitance effect on gain, noise figure, and linearity of the circuit, extra inductors and capacitors are added between the switching and transconductance stages. The proposed mixer is simulated in 0.18-$\mu $m RF-CMOS technology with a 1.8-V supply. The results show an improvement of about 23 dBm in IIP3 compared to conventional mixers. The power consumption of this circuit is about 3.96 mW.
Design And Analysis Of A Novel Uwb Bandpass Filter Using 3-D Em Simulation-Based Neural Network Model With Hsa,
2016
TÜBİTAK
Design And Analysis Of A Novel Uwb Bandpass Filter Using 3-D Em Simulation-Based Neural Network Model With Hsa, Sali̇h Demi̇rel, Cafer Uyanik
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a new systematic analysis and design of the ultrawide-band bandpass filter by using the 3-D electromagnetic simulation-based multilayer perceptron neural network (MLP NN) model of unit elements. This MLP NN model is utilized efficiently as a fast and accurate model within a harmony search algorithm (HSA) procedure to determine the resultant optimum microstrip structure geometry. Moreover, the validity and efficiency of the HSA is manifested by comparing it with those of the standard metaheuristics, which are genetic and particle swarm algorithms. The filter that shows the best performance is designed and realized. Measurements taken from the realized …
Comprehensive Review Of Association Estimators For The Inference Of Gene Networks,
2016
TÜBİTAK
Comprehensive Review Of Association Estimators For The Inference Of Gene Networks, Zeyneb Kurt Yavuz, Ni̇zametti̇n Aydin, Gökmen Altay
Turkish Journal of Electrical Engineering and Computer Sciences
Gene network inference (GNI) algorithms allow us to explore the vast amount of interactions among the molecules in cells. In almost all GNI algorithms the main process is to estimate association scores among the variables of the dataset. However, there is no commonly accepted estimator to compute association scores for the current GNI algorithms. In this paper the association estimators that might be used in GNI applications are reviewed. The aim is to prepare a comprehensive and comparative review of all the important association estimators available in the literature. We performed this main aim by presenting, classifying, comparing, and discussing …
Discriminant-Based Bistability Analysis Of A Tmg-Induced Lac Operon Model Supported With Boundedness And Local Stability Results, Nesli̇han Avcu, Güleser Kalayci Demi̇r, Ferhan Pekergi̇n, Hakan Alyürük, Levent Çavaş, Cüneyt Güzeli̇ş
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents the results of a theoretical and numerical study on the analysis of bistable behavior of the most studied gene regulatory network, the lac operon, in terms of the model parameters. The boundedness of the state variables for the considered model are demonstrated, the parameter values providing the existence of the multiple equilibria and thus the bistable behavior are determined, and a local stability analysis of the equilibria is performed. The parameter region yielding the existence of multiple equilibria is determined in an algebraic way based on discriminants. The model given in the state equation form is defined …
