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Articles 4291 - 4320 of 7215

Full-Text Articles in Computer Engineering

Design Of Low Power Cmos Lc Vco For Direct Conversion Transceiver, Manjula Sankararaju, Selvathi Dharmar Jan 2016

Design Of Low Power Cmos Lc Vco For Direct Conversion Transceiver, Manjula Sankararaju, Selvathi Dharmar

Turkish Journal of Electrical Engineering and Computer Sciences

No abstract provided.


Novel Dynamic Partial Reconfiguration Implementations Of The Support Vector Machine Classifier On Fpga, Hanaa Hussain, Khaled Benkrid, Hüseyi̇n Şeker Jan 2016

Novel Dynamic Partial Reconfiguration Implementations Of The Support Vector Machine Classifier On Fpga, Hanaa Hussain, Khaled Benkrid, Hüseyi̇n Şeker

Turkish Journal of Electrical Engineering and Computer Sciences

The support vector machine (SVM) is one of the highly powerful classifiers that have been shown to be capable of dealing with high-dimensional data. However, its complexity increases requirements of computational power. Recent technologies including the postgenome data of high-dimensional nature add further complexity to the construction of SVM classifiers. In order to overcome this problem, hardware implementations of the SVM classifier have been proposed to benefit from parallelism to accelerate the SVM. On the other hand, those implementations offer limited flexibility in terms of changing parameters and require the reconfiguration of the whole device. The latter interrupts the operation …


Tourism Demand Modelling And Forecasting Using Data Mining Techniques In Multivariate Time Series: A Case Study In Turkey, Selçuk Cankurt, Abdülhami̇t Subaşi Jan 2016

Tourism Demand Modelling And Forecasting Using Data Mining Techniques In Multivariate Time Series: A Case Study In Turkey, Selçuk Cankurt, Abdülhami̇t Subaşi

Turkish Journal of Electrical Engineering and Computer Sciences

In this study multiple linear regression, multilayer perceptron (MLP) regression, and support vector regression (SVR) are used to make multivariate tourism forecasting for Turkey. This paper is a comparative study of data mining techniques based on multivariate regression modelling with monthly data points to forecast tourism demand; it focuses on Turkey. Both MLP and SVR methods are widely employed in the variety forecasting problems. Most of the previous research on tourism forecasting used univariate time series or a limited number of variables with mostly yearly or quarterly, and rarely monthly frequencies. However, the application of data mining techniques for multivariate …


Intensity Exposure-Based Bi-Histogram Equalization For Image Enhancement, Tang Jing Rui, Nor Ashidi Mat Isa Jan 2016

Intensity Exposure-Based Bi-Histogram Equalization For Image Enhancement, Tang Jing Rui, Nor Ashidi Mat Isa

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we present a study of the usage of intensity exposure in histogram segmentation and its performance in histogram equalization. Two techniques are proposed: the mean-based bi-histogram equalization plateau limit (mean-BHEPL) or median-based BHEPL (median-BHEPL) and adaptive bi-histogram equalization algorithm (ABHE). Both techniques initially divide the input histogram into two subhistograms through a threshold value computed from the intensity exposure of the image. Histogram clipping for mean-BHEPL and median-BHEPL is then performed on these subhistograms using the mean and median values, respectively. Conventional histogram equalization is also implemented on each clipped subhistogram. The second proposed technique, ABHE, applies …


A Current-Based Simple Analog Mppt Circuit For Pv Systems, Bülent Büyükgüzel, Murat Aksoy Jan 2016

A Current-Based Simple Analog Mppt Circuit For Pv Systems, Bülent Büyükgüzel, Murat Aksoy

Turkish Journal of Electrical Engineering and Computer Sciences

A new single pilot-sensor maximum power point tracking (MPPT) system, consisting of a buck type DC/DC converter, was developed. It is controlled by an analog-based unit. The main difference between the proposed MPPT system and other systems is that the short circuit current of the pilot-PV module in our system is used to control the DC/DC converter. The circuit of the proposed system does not utilize an expensive digital signal processor nor a microcontroller; hence, the cost and the complexity of the system are reduced.


Process Time And Mppt Performance Analysis Of Cf, Lut, And Ann Control Methods For A Pmsg-Based Wind Energy Generation System, Abdulhaki̇m Karakaya, Ercüment Karakaş Jan 2016

Process Time And Mppt Performance Analysis Of Cf, Lut, And Ann Control Methods For A Pmsg-Based Wind Energy Generation System, Abdulhaki̇m Karakaya, Ercüment Karakaş

Turkish Journal of Electrical Engineering and Computer Sciences

Due to environmental issues such as global warming and the greenhouse effect, there is a growing interest in renewable sources of energy. Wind energy, which is the most important of these energy sources, can potentially meet a portion of the global energy demand. Numerous studies are being conducted worldwide to determine how the maximum level of power can be obtained from wind energy. In these studies, there is a particular interest in permanent magnet synchronous generators (PMSGs). This is because PMSGs exhibit a good performance within a wide range wind speeds and can be driven directly. In this study, the …


Autonomous Navigation With Obstacle Avoidance For Unmanned Aircraft Systems Using Milp, James A. Devens Jan 2016

Autonomous Navigation With Obstacle Avoidance For Unmanned Aircraft Systems Using Milp, James A. Devens

Theses and Dissertations

Autonomous coordination among multiple aerial vehicles to ensure a collision free airspace is a critical aspect of today’s airspace. With the rise of Unmanned Aerial Vehicles (UAVs) in the military and commercial sectors, obstacle avoidance in a densely populated airspace is necessary. This thesis investigates finding optimal or near-optimal trajectories in real-time for aircraft in complex airspaces containing a large number of obstacles. The solution for the trajectories is described as a linear program subject to mixed integer constraints, known as a Mixed Integer Linear Program (MILP). The resulting MILP problem is solved in real time using a well-known, public …


The Phononic Crystal Interface Layer Determines Slow-Wave And Pulse Broadening Effects, Li Sun, Aiming Ji, Jialing Hu, Canyan Zhu, Lijun Zhang, Jianfeng Yang, Lingfeng Mao Jan 2016

The Phononic Crystal Interface Layer Determines Slow-Wave And Pulse Broadening Effects, Li Sun, Aiming Ji, Jialing Hu, Canyan Zhu, Lijun Zhang, Jianfeng Yang, Lingfeng Mao

Turkish Journal of Electrical Engineering and Computer Sciences

The relationship among the slow-wave and echo pulse broadening effects in reflected acoustic waves and the width of the interface layer of phononic crystal has been theoretically investigated. It has been observed that not only the slow time for the reflected acoustic wave but also the echo pulse broadening reaches a saturation point as the size of the phononic crystal increases. From the viewpoint of the acoustic wave, there is an interface layer in the crystal that determines the slow-wave and the echo pulse broadening effects. The longest slow time, which is the time needed for transmitting 0.08 periods of …


A Hybrid Search Method Of Wrapper Feature Selection By Chaos Particle Swarm Optimization And Local Search, Mohammad Masoud Javidi, Nasibeh Emami Jan 2016

A Hybrid Search Method Of Wrapper Feature Selection By Chaos Particle Swarm Optimization And Local Search, Mohammad Masoud Javidi, Nasibeh Emami

Turkish Journal of Electrical Engineering and Computer Sciences

Finding a subset of features from a large dataset is a problem that arises in many fields of study. Since the increasing number of features has extended the computational cost of a system, it is necessary to design and implement a system with the least number of features. The purpose of feature selection is to find the best subset of features from the original ones. The result of the best selection is improving the computational cost and the accuracy of the prediction. A large number of algorithms have been proposed for feature subset selection. In this paper, we propose a …


A Ring Crossover Genetic Algorithm For The Unit Commitment Problem, Syed Basit Ali Bukhari, Aftab Ahmad, Syed Auon Raza, Muhammad Noman Siddique Jan 2016

A Ring Crossover Genetic Algorithm For The Unit Commitment Problem, Syed Basit Ali Bukhari, Aftab Ahmad, Syed Auon Raza, Muhammad Noman Siddique

Turkish Journal of Electrical Engineering and Computer Sciences

The unit commitment problem (UCP) is a nonlinear, mixed-integer, constraint optimization problem and is considered a complex problem in electrical power systems. It is the combination of two interlinked subproblems, namely the generator scheduling problem and the generation allocation problem. In large systems, the UCP turns out to be increasingly complicated due to the large number of possible ON and OFF combinations of units in the power system over a scheduling time horizon. Due to the insufficiency of conventional approaches in handling large systems, numerous metaheuristic techniques are being developed for solving this problem. The genetic algorithm (GA) is one …


Electric Arc Furnace Power Quality Improvement By Applying A New Digital And Predicted-Based Tsc Control, Mehdi Torabian Esfahani, Behrooz Vahidi Jan 2016

Electric Arc Furnace Power Quality Improvement By Applying A New Digital And Predicted-Based Tsc Control, Mehdi Torabian Esfahani, Behrooz Vahidi

Turkish Journal of Electrical Engineering and Computer Sciences

Static VAR compensators (SVC) can improve some of the power quality (PQ) indices such as voltage flicker, unbalances, and power factors in power systems if properly controlled. Different nonlinear and time-varying loads generate these parameters. One of the great nonlinear loads is the electric arc furnace (EAF), which causes waveform distortions, voltage unbalances, and fluctuations. In this paper, a new digital and prediction-based control for thyristor switched capacitors (TSCs) was proposed to compensate an actual steel industrial plant. The digital control was based on generating adequate synchronous pulses, calculating required suitable susceptance, and measuring correct reactive power. The proposed TSC …


Fuzzy Speed Estimation In The Case Of Sensorless Induction Machine Vector Control, Mohamed Bahloul, Mansour Souissi, Mohamed Chaabane, Larbi Chrifi Alaoui, Said Drid Jan 2016

Fuzzy Speed Estimation In The Case Of Sensorless Induction Machine Vector Control, Mohamed Bahloul, Mansour Souissi, Mohamed Chaabane, Larbi Chrifi Alaoui, Said Drid

Turkish Journal of Electrical Engineering and Computer Sciences

This paper deals with the problem of sensorless indirect field oriented control of an induction machine. Based on the fourth-order nonlinear model, we propose a novel structure of a full-order Takagi-Sugeno (TS) adaptive observer, through which we ensure the estimation of IM states and the rotor speed, which is considered as an immeasurable premise variable. This approach satisfies global stability for all operating conditions and operates under unknown applied load torque. In this work, a TS fuzzy model is presented to approximate a nonlinear IM model in the stationary rotating reference frame. A TS adaptive observer is then described. We …


Using Magnetic Field Analysis To Evaluate The Suitability Of A Magnetic Suspension System For Lightweight Vehicles, Hazril Md Isa, Noor Hafizah Amer, Wan Nor Liza Wan Mahadi, Rahizar Ramli Jan 2016

Using Magnetic Field Analysis To Evaluate The Suitability Of A Magnetic Suspension System For Lightweight Vehicles, Hazril Md Isa, Noor Hafizah Amer, Wan Nor Liza Wan Mahadi, Rahizar Ramli

Turkish Journal of Electrical Engineering and Computer Sciences

A suspension system in a vehicle acts as an isolator that isolates vibrations between the wheel tires and the vehicle body due to road irregularities. Additionally, a suspension system serves as a vehicle stabilizer that stabilizes the vehicle body during unusual driving patterns such as cornering, braking, or accelerating. A controllable suspension system has received significant attention in the automotive world in previous years since it can perform both of the aforementioned tasks without the presence of fluid damper. The study presented in this paper focuses on using magnetic flux density analysis to evaluate a number of parameters of an …


Energy-Aware Stochastic Scheduling Model With Precedence Constraints On Dvfs-Enabled Processors, Mohammad Sajid, Zahid Raza Jan 2016

Energy-Aware Stochastic Scheduling Model With Precedence Constraints On Dvfs-Enabled Processors, Mohammad Sajid, Zahid Raza

Turkish Journal of Electrical Engineering and Computer Sciences

The stochastic scheduling of precedence-constrained jobs on a heterogeneous processor is a challenging problem that requires solutions with one or more optimized QoS parameters. In this work, an energy-aware stochastic algorithm is proposed to schedule the batch of precedence-constrained jobs on heterogeneous DVFS-enabled processors with the objective of optimizing turnaround time and energy consumption. The processing time of tasks in all jobs and their precedence-constraint times are governed by independent probability distributions. The performance of the proposed stochastic algorithm is compared with SHEFT and ECS based on randomly generated batches of different sizes. The experimental study reveals that the proposed …


A Switching Inverse Dynamics Controller For Parallel Manipulators Around Drive Singular Configurations, Mustafa Özdemi̇r, Sitki Kemal İder Jan 2016

A Switching Inverse Dynamics Controller For Parallel Manipulators Around Drive Singular Configurations, Mustafa Özdemi̇r, Sitki Kemal İder

Turkish Journal of Electrical Engineering and Computer Sciences

Despite many advantages, parallel manipulators are known to possess drive singularities where the control of one or more degrees of freedom is lost. Around these singular configurations, the required actuator forces grow unbounded. Previous efforts in the literature put forward singularity-consistent trajectory planning and singularity-robust modification of the dynamic equations as a solution to this problem. However, this previous method is applicable only for the open-loop operation of the manipulator, whereas initial configuration errors, external disturbances, and modeling errors should necessarily be taken into account in a closed-loop sense in real-life applications. With this aim, a switching inverse dynamics controller …


Exploring Feature Sets For Turkish Word Sense Disambiguation, Bahar İlgen, Eşref Adali, Ahmet Cüneyd Tantuğ Jan 2016

Exploring Feature Sets For Turkish Word Sense Disambiguation, Bahar İlgen, Eşref Adali, Ahmet Cüneyd Tantuğ

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents an exploration and evaluation of a diverse set of features that influence word-sense disambiguation (WSD) performance. WSD has the potential to improve many natural language processing (NLP) tasks as being one of the most crucial steps in the area. It is known that exploiting effective features and removing redundant ones help improving the results. There are two groups of feature sets to disambiguate senses and select the most appropriate ones among a set of candidates: collocational and bag-of-words (BoW) features. We introduce the effects of using these two feature sets on the Turkish Lexical Sample Dataset (TLSD), …


Digital Implementation Of A Constant Frequency Hysteresis Controller For Dual Mode Operation Of An Inverter Acting As A Pv-Grid Interface And Statcom, Lenin Prakash, Arutchelvi Meenakshi Sundaram, Kalyanraj Durairaj Jan 2016

Digital Implementation Of A Constant Frequency Hysteresis Controller For Dual Mode Operation Of An Inverter Acting As A Pv-Grid Interface And Statcom, Lenin Prakash, Arutchelvi Meenakshi Sundaram, Kalyanraj Durairaj

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a new constant frequency hysteresis current controller for the grid interface of a PV-fed three-phase voltage source inverter (VSI) for a dual mode operation, feeding real power during the daytime and reactive power alone during nights, thereby acting as a STATCOM. The constant frequency is inherently achieved by means of digital implementation in a simplified manner without any complex manipulations to choose a variable band width; rather the hysteresis band varies as a natural consequence of selecting appropriate constant sampling frequency. Analytical proof is presented for the switching frequency to remain constant, without compromising on the performance …


The Simulation Of Sound Signal Masking With Different Chaotic Oscillations And Its Circuit Application, Mehmet Nuri̇ Almali, Zi̇nnur Di̇ki̇ci̇ Jan 2016

The Simulation Of Sound Signal Masking With Different Chaotic Oscillations And Its Circuit Application, Mehmet Nuri̇ Almali, Zi̇nnur Di̇ki̇ci̇

Turkish Journal of Electrical Engineering and Computer Sciences

The chaotic masking process on sound signals using the systems of Lorenz, Rössler, Sprott, Chen, and Arneodo chaotic oscillations are simulated with MATLAB/Simulink. The PID control method providing synchronization in the system is defined and the mean square errors between the times to reach synchronization and the input-output sound signals are compared for the system performance. The Sprott chaotic system is found to be the best synchronized system. Therefore, the application circuits are designed with respect to the Sprott chaotic system and its results are investigated in this study. It is seen that the system marked with the Sprott chaotic …


Improving Response Time Of Database Systems By Semantification Of Relational Data, Mustafa Yeni̇ad, Yakup Kutlu Jan 2016

Improving Response Time Of Database Systems By Semantification Of Relational Data, Mustafa Yeni̇ad, Yakup Kutlu

Turkish Journal of Electrical Engineering and Computer Sciences

New generation web technologies present the new problem of intelligent representation of data in semantically structured systems. In this study, data hosted in a relational database system were converted to a new generation of web technologies (i.e. Web 3.0) with the semantic mapping method and semantification of the data was accomplished. The success of the transformation procedure was verified by a cross-comparison of the data between the relational database and the semantic data repository. By comparing the response time for performing SQL queries and equivalent SPARQL queries such as select, insert, update, and delete, operations hold in the semantic data …


A Comprehensive Control Strategy Of Railway Power Quality Compensator For Ac Traction Power Supply Systems, Hamed Jafari Kaleybar, Siamak Farshad Jan 2016

A Comprehensive Control Strategy Of Railway Power Quality Compensator For Ac Traction Power Supply Systems, Hamed Jafari Kaleybar, Siamak Farshad

Turkish Journal of Electrical Engineering and Computer Sciences

The development of electrical railway systems leads to critical power quality problems in the power grid. This paper discusses a kind of half-bridge-based railway power quality compensator system (HBRPQC) that can compensate negative sequence currents, harmonics, and reactive power simultaneously. In order to keep the HBRPQC performance efficient for the different kinds of transformers used in traction power supply substations, a new multifunctional control strategy that performs better than previous methods is proposed. Due to the fast dynamicity of traction loads, a recessive self-tuning PI controller based on fuzzy logic is adopted in the current control system. The output control …


Computer-Assisted Cobb Angle Measurement From Posteroanterior Radiographs By A Curve Fitting Method, İbrahi̇m Yildiz Jan 2016

Computer-Assisted Cobb Angle Measurement From Posteroanterior Radiographs By A Curve Fitting Method, İbrahi̇m Yildiz

Turkish Journal of Electrical Engineering and Computer Sciences

Incorrect determination of the top or end vertebrae of a scoliotic curve causes measurement errors when using the Cobb method. Such problems are due to subjectivity. This study was performed to minimize subjectivity by using a curve fitting method. A digitally scanned posteroanterior radiographic image was used for each patient. User-defined midpoints of the curvature, which indicate the midpoints of the vertebrae, were used to fit the polynomial equation. The locations of the top and end vertebrae were calculated using the first derivative of the fitted polynomial equation to obtain the analytical Cobb angle. The interobserver technical error of measurements …


Certain Investigations On Power Generation Using Repulsive Magnets And New Stepped Dc Coupled Quasi Z-Inverter, Meenakshi Thillainayagam, Suthanthira Vanitha Narayanan, Sujith Kumar Sivaraman Jan 2016

Certain Investigations On Power Generation Using Repulsive Magnets And New Stepped Dc Coupled Quasi Z-Inverter, Meenakshi Thillainayagam, Suthanthira Vanitha Narayanan, Sujith Kumar Sivaraman

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a novel approach for power generation from rotating machines in textile mills using externally coupled repulsive magnets and a new stepped DC coupled Quasi Z-inverter. Power is obtained as a byproduct of the effective harnessing of rotational energy with the use of repulsive magnets. This derived power is stored in a battery arrangement and is retrieved, buck/boosted, and converted to multilevel AC voltage with the new stepped DC coupled quasi Z-inverter. The proposed inverter is powered by isolated voltage sources, uses fewer switches, and produces less distortion in the resulting multilevel voltage compared to its counterpart, and …


An Interval-Based Contingency Selection Approach Considering Uncertainty, Chao Xu, Wei Gu, Lizi Luo, Jianguo Yao, Shengchun Yang, Ke Wang, Dan Zeng, Miao Fan Jan 2016

An Interval-Based Contingency Selection Approach Considering Uncertainty, Chao Xu, Wei Gu, Lizi Luo, Jianguo Yao, Shengchun Yang, Ke Wang, Dan Zeng, Miao Fan

Turkish Journal of Electrical Engineering and Computer Sciences

Static security assessment is affected by uncertainties of load flow distributions introduced by renewable sources. A fast contingency selection approach based on interval theory is proposed in this paper. Firstly, an interval line active flow calculation algorithm is developed to reduce conservation in application of interval mathematics in line flow calculation. Then a novel interval comparison method based on Bayesian probability theory is applied in interval index comparison to give the relative severity information of contingencies. Finally, an approximately consistent ranking method is utilized in contingency ranking to rank screened contingencies. Numerical studies on several IEEE standard test systems and …


Validation Of Trnsys Modelling For A Fixed Slope Photovoltaic Panel, Kant Kanyarusoke, Jasson Gryzagoridis, Graeme Oliver Jan 2016

Validation Of Trnsys Modelling For A Fixed Slope Photovoltaic Panel, Kant Kanyarusoke, Jasson Gryzagoridis, Graeme Oliver

Turkish Journal of Electrical Engineering and Computer Sciences

TRNSYS stands for transient system simulation software. This paper describes a procedure that was used to validate a TRNSYS model for estimating electricity yields from a fixed slope photovoltaic (PV) panel. The objective was to find how close to reality predicted energy yield for a specified panel can be, at a location near one of the weather stations listed in the software's database. The software was used to predict daily total incident radiation on a horizontal plane and electrical energy yields from a 90 Wp panel when sloped at 34$^{\circ}$ facing north at a test site in Cape Town, South …


Integration Of Spectral And Spatial Information Via Local Covariance Matrices For Segmentation And Classification Of Hyperspectral Images, Uğur Ergül, Gökhan Bi̇lgi̇n Jan 2016

Integration Of Spectral And Spatial Information Via Local Covariance Matrices For Segmentation And Classification Of Hyperspectral Images, Uğur Ergül, Gökhan Bi̇lgi̇n

Turkish Journal of Electrical Engineering and Computer Sciences

In this work, a novel approach is presented for the feature extraction step in hyperspectral image processing to form more discriminative features between different pixel regions. The proposed method combines both spatial and spectral information, which is very important for segmentation and classification of hyperspectral images. For comparison, five different feature sets are formed using eigen decomposition of local covariance matrices of subcubes located around a pixel of interest in the scene. Subcubes of neighbor pixels are obtained by a windowed structure to expose pattern similarities. As a novel approach, local covariance matrices are computed in eigenspace and proposed feature …


Assessment Of Energy Performance Certificate Systems: A Case Study For Residential Buildings In Turkey, Kenan Yi̇ği̇t, Bora Acarkan Jan 2016

Assessment Of Energy Performance Certificate Systems: A Case Study For Residential Buildings In Turkey, Kenan Yi̇ği̇t, Bora Acarkan

Turkish Journal of Electrical Engineering and Computer Sciences

The importance of sustainable development and energy efficiency efforts has increased in the construction sector. Energy-saving efforts for buildings have become more important due to the global energy crisis, and energy rating systems have been developed globally for assessment of energy performance. In this study, international green building certificate and energy performance certificate (EPC) systems are presented. The official EPC system for buildings in Turkey is illustrated with case studies. Energy consumption and greenhouse gas emissions from residential buildings are calculated using the official national software, which is called BEP-TR. The impact of lighting on the total energy performance of …


Effect Of Transverse Magnetic Field On Low Pressure Argon Discharge, Ehsan Hashemi, Kaveh Niayesh, Hossein Mohseni Jan 2016

Effect Of Transverse Magnetic Field On Low Pressure Argon Discharge, Ehsan Hashemi, Kaveh Niayesh, Hossein Mohseni

Turkish Journal of Electrical Engineering and Computer Sciences

A numerical simulation was performed to investigate the effect of transverse magnetic fields on low pressure argon plasma. Discovering the variations in electric field, electric potential, power consumption in plasma, and dominant physical mechanisms after application of magnetic fields is the main output of this analysis. A simulation was performed using the finite element method. A 2-fluid model equipped with chemical reaction equations in argon plasma, heat transfer equation, and Poisson's equation was used to describe the plasma behavior. Two disk-shaped electrodes separated by 12 mm from each other were considered as a plasma chamber and an external transverse magnetic …


Minimum Number Of Permanent-Magnet Synchronous Generators For Coordinated Low-Voltage Ride-Through Of Induction Generators In Hybrid Wind Farms, Shenghu Li, Rui An Jan 2016

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, Hamid Shariatpanah, Morteza Sabouri Kenari, Roohollah Fadaeinedjad Jan 2016

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, Zeinulla Zhanabaev, Yeldos Kozhagulov, Dauren Zhexebay Jan 2016

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.