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Articles 2281 - 2310 of 2767
Full-Text Articles in Computer Sciences
E-Mfdbscan: An Evolutionary Clustering Algorithm For Gene Expression Time Series, Atakan Erdem, Taflan İmre Gündem
E-Mfdbscan: An Evolutionary Clustering Algorithm For Gene Expression Time Series, Atakan Erdem, Taflan İmre Gündem
Turkish Journal of Electrical Engineering and Computer Sciences
DNA microarray experiments are frequently used because they have various advantages. However, gene expression data from DNA microarray experiments are noisy, and, consequently, the computations that are based on such noisy data may lack accuracy. In this paper, an evolutionary uncertain data-clustering algorithm, E-MFDBSCAN, and a prediction model using E-MFDBSCAN for uncertain data are proposed. The proposed methodology may be successfully applied to noisy gene expression data. In this methodology, global patterns of time series data can be extracted using our evolutionary clustering approach. These patterns are used to infer future projections. In the proposed methodology, an autoregressive time series …
Modeling And Simulation Of 2.5 Mva Sf6-Gas-Insulated Transformer, Okan Özgönenel, David Thomas
Modeling And Simulation Of 2.5 Mva Sf6-Gas-Insulated Transformer, Okan Özgönenel, David Thomas
Turkish Journal of Electrical Engineering and Computer Sciences
In recent years, environmental awareness has been a great concern, and even governments have sometimes been under pressure to comply with bilateral agreements. Mineral oil/epoxy cast resins are one of the most harmful soil pollutants. Of course, they provide a good insulation material in (distribution/power) transformers, but they present some disadvantages, such as low ignition point, additional insulation costs, requirement for an extinguishing apparatus, long clearance distance, toxicity, costly decontamination, and explosion risk. For this reason, gas-insulated transformers have nowadays been put into specifications. % This paper investigates SF6-gas-insulated transformer (GIT) designs for the complex distribution transformer model, i.e. 2.5 …
A Linear Magnetorheological Brake With Multipole Outer Coil Structure For High On-State And Low Off-State Force Outputs, Özgür Başer, Mehmet Alper Demi̇ray, Aytuğ Baş, Ergi̇n Kiliç, Gali̇p Ozan Erol
A Linear Magnetorheological Brake With Multipole Outer Coil Structure For High On-State And Low Off-State Force Outputs, Özgür Başer, Mehmet Alper Demi̇ray, Aytuğ Baş, Ergi̇n Kiliç, Gali̇p Ozan Erol
Turkish Journal of Electrical Engineering and Computer Sciences
A wide range of braking forces, from near zero to high values, is required in specific applications such as forces in haptic devices or steering stability in motorcycles. Classical piston cylinder type magnetorheological (MR) brakes are not suitable for these applications due to their high off-state forces. In this paper, a new linear type MR brake employing shear mode braking principle with a multipole outer coil structure is presented for high on-state and low off-state force outputs. To implement this device, an analytical model of the brake is derived by using magnetic circuit analysis to determine braking force. Magnetic finite …
Improved Resettable Integrator Control For A Bridgeless Interleaved Ac/Dc Converter, Kanimozhi Gunasekaran, Sreedevi Vellithirothi Thazhathu
Improved Resettable Integrator Control For A Bridgeless Interleaved Ac/Dc Converter, Kanimozhi Gunasekaran, Sreedevi Vellithirothi Thazhathu
Turkish Journal of Electrical Engineering and Computer Sciences
Plug-in hybrid electric vehicles (PHEVs) consist of a front-end boost rectifier, which incorporates a power factor correction (PFC) circuit for battery charging. Bridgeless interleaved (BLIL) PFC boost converter topology is proved as a standard PFC converter as it has high efficiency, reduced input current ripple, and reduced electromagnetic interference (EMI). This paper proposes a digital nonlinear control technique that employs a resettable integrator to shape the input current of the converter in phase with the input voltage to achieve high input power factor. This control approach rejects power source and load perturbations better than linear feedback control methods. This is …
Force And Torque Parameter Estimation For A 4-Pole Hybrid Electromagnet By Anfis Hybrid Learning Algorithm, Murat Atlihan, Bariş Can Yalçin, Kadi̇r Erkan
Force And Torque Parameter Estimation For A 4-Pole Hybrid Electromagnet By Anfis Hybrid Learning Algorithm, Murat Atlihan, Bariş Can Yalçin, Kadi̇r Erkan
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, a force and torque estimation method based on an adaptive neuro-fuzzy inference system (ANFIS) has been developed to get rid of multiple integral calculations of air gap coefficients that cause time delay for magnetic levitation control applications. During magnetic levitation applications that contain a 4-pole hybrid electromagnet, multiple integral calculations have to be done for obtaining air gap permanence parameters, and these parameters are needed to calculate force and torque parameters that are produced by the poles of the hybrid electromagnet, which means, if time delay occurs for calculation of permanence parameters, actual force and actual torque …
Space-Time Block Coded Spatial Modulation Scheme Enhanced By Employing An Intersymbol Phase And Power Allocation, Ahmet Faruk Coşkun
Space-Time Block Coded Spatial Modulation Scheme Enhanced By Employing An Intersymbol Phase And Power Allocation, Ahmet Faruk Coşkun
Turkish Journal of Electrical Engineering and Computer Sciences
This paper provides a brief and insightful examination of the advantages achieved by employing combined phase offsetting and power allocation mechanisms in the space-time block coded (STBC) transmission of spatial modulation schemes with cyclic structure (CSM). In order to achieve increased coding gain distances (CGDs) between transmitted code words (CWs), the power allocation mechanism is cascaded to the constellation mapping process of a STBC-CSM scheme, and the optimal power and phase weights for the conveyed information symbols, together with the phases for each CW, are searched by a heuristic algorithm based on differential evolution that yields the best CGD available …
Promoting Peak Shaving While Minimizing Electricity Consumption Payment For Residential Consumers By Using Storage Devices, Simona Oprea, Adela Bara, Mahmut Erkut Cebeci̇, Osman Bülent Tör
Promoting Peak Shaving While Minimizing Electricity Consumption Payment For Residential Consumers By Using Storage Devices, Simona Oprea, Adela Bara, Mahmut Erkut Cebeci̇, Osman Bülent Tör
Turkish Journal of Electrical Engineering and Computer Sciences
Nowadays, smart meters, sensors, and advanced electricity tariff mechanisms such as time-of-use (ToU), critical peak pricing tariff, and real time tariff enable electricity consumption optimization for residential consumers. The main scope of such mechanisms is to promote peak shaving, which leads to minimization of technical losses and avoidance (or delay) of grid onerous investments. This paper proposes a method to determine the optimum capacity of a storage device (SD) that significantly contributes to peak shaving of electricity consumption for residential consumers. Detailed modelling of diverse electric appliances' behavior and consumers' necessities is addressed in order to determine the optimum capacity …
The Design Of A Novel And Portable Energy Performance-Measuring Device For Household Refrigerators, İlhan Koşalay, Okan Bi̇ngöl, Hakki Gökhan İlk, Mahmut Yildirim, Burçi̇n Özkaya
The Design Of A Novel And Portable Energy Performance-Measuring Device For Household Refrigerators, İlhan Koşalay, Okan Bi̇ngöl, Hakki Gökhan İlk, Mahmut Yildirim, Burçi̇n Özkaya
Turkish Journal of Electrical Engineering and Computer Sciences
Refrigerators are one of the main devices used in our daily lives, and they play important roles in storing food and maintaining its freshness. Refrigerator manufacturing is improving day by day and it is important for the appliance to present a diverse array of functions to its users, since usage requirements vary from region to region. For this purpose, refrigerators must pass through various performance tests like an energy efficiency test while they are produced in factories. Factories have designated testing rooms for these performance tests. After the products' release, technical services and customers do not have such a luxury …
Fault Location In Distribution Systems With Dg Based On Similarity Of Fault Impedance, Zahra Moravej, Omid Hajhossani, Mohammad Pazoki
Fault Location In Distribution Systems With Dg Based On Similarity Of Fault Impedance, Zahra Moravej, Omid Hajhossani, Mohammad Pazoki
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a new method for locating a fault in distribution systems using the similarity of fault impedance. A four-step approach is proposed to locate the fault in the networks. First, pre- and during-fault voltages from smart feeders along the primary feeders are measured. Second, three-phase impedance to calculate fault current corresponding to voltage deviation from each smart meter is achieved. Third, a relation between fault current and fault impedance for each type of fault is extracted. Finally, based on the similarity of the estimated fault impedance for each bus, an error index is calculated. Moreover, an auxiliary process …
A Spatial Load Forecasting Method Based On Load Regularity Analysis, Bai Xiao, Tongtong Liu
A Spatial Load Forecasting Method Based On Load Regularity Analysis, Bai Xiao, Tongtong Liu
Turkish Journal of Electrical Engineering and Computer Sciences
A new method, based on regularity analysis of cellular load, is presented to determine the reasonable maximum of the load density index method of spatial load forecasting (SLF). Through analysis of cellular historical load data, each cellular load is decomposed into regular and random components. The regular part is used to reveal the regularity of the cellular load in different cycles, using random components to describe and characterize the intrinsic error of the cellular load. Adverse effects that occur by eliminating random components to suppress the intrinsic error allow extraction of the maximum of the regular part as the Class …
Inverse Kinematics Of A 7-Dof Redundant Robot Manipulator Using The Active Set Approach Under Joint Physical Limits, Modjtaba Rouhani, Sima Ebrahimabadi
Inverse Kinematics Of A 7-Dof Redundant Robot Manipulator Using The Active Set Approach Under Joint Physical Limits, Modjtaba Rouhani, Sima Ebrahimabadi
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a new approach for an online solution of the inverse kinematics problem based on nonlinear optimization for robots with joint physical constraints. The inverse kinematics problem is stated as a constrained nonlinear optimization problem and is solved using Kuhn--Tucker conditions analysis. The nonlinear multivariable optimization problem is locally converted into independent local linear constrained subproblems and each subproblem is analytically solved. For each joint, position limits and velocity limits are considered as physical constraints. The proposed structure benefits from a very low complexity design. The proposed method is fast and requires few calculations. The convergence of the …
A Model Of Optimal Burst Assembly For Delay Reduction At Ingress Obs Nodes, Viet Minh Nhat Vo, Van Hoa Le, Hoang Son Nguyen
A Model Of Optimal Burst Assembly For Delay Reduction At Ingress Obs Nodes, Viet Minh Nhat Vo, Van Hoa Le, Hoang Son Nguyen
Turkish Journal of Electrical Engineering and Computer Sciences
Burst assembly plays an important role in reducing the end-to-end delay of packets transported through optical burst switching (OBS) networks. Several methods have been proposed to reduce the delay of the packets buffered at ingress OBS nodes. However, these have created significant estimation errors, which result in wasting the reserved bandwidth or increasing the delay of excess packets. In this paper, we propose a model of optimal burst assembly for delay reduction, which minimizes the estimation error, eliminates the excess packets, and decreases the blocking probability of scheduling.
Low-Frequency Exposure Analysis Using Electric And Magnetic Field Measurements And Predictions In The Proximity Of Power Transmission Lines In Urban Areas, Hamza Feza Carlak, Şükrü Özen, Süleyman Bi̇lgi̇n
Low-Frequency Exposure Analysis Using Electric And Magnetic Field Measurements And Predictions In The Proximity Of Power Transmission Lines In Urban Areas, Hamza Feza Carlak, Şükrü Özen, Süleyman Bi̇lgi̇n
Turkish Journal of Electrical Engineering and Computer Sciences
In recent years, increasing energy demand has resulted in more loading in power transmission lines and correspondingly more electric and magnetic field occurrence. In this paper, electric and magnetic field levels around high voltage power transmission lines are measured and then calculated analytically by simulating the realistic case. Moreover, the field levels around these power lines have been predicted using multilayer perceptron artificial neural network (ANN) and generalized regression neural network models. Typical 154 kV power transmission line facilities of Turkey have been studied. Electric and magnetic field levels in the proximity of power transmission lines have been predicted with …
A Low Power Memoryless Rom Design Architecture For A Direct Digital Frequency Synthesizer, Salah Alkurwy, Sawal Ali, Md.Shabiul Islam, Md. Faizul Idros
A Low Power Memoryless Rom Design Architecture For A Direct Digital Frequency Synthesizer, Salah Alkurwy, Sawal Ali, Md.Shabiul Islam, Md. Faizul Idros
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a novel, memoryless, read-only memory (ROM) design architecture for a direct digital frequency synthesizer (DDFS). A pipelining technique is proposed to increase the phase accumulator (PA) throughput. However, this technique increases the number of registers as the pipeline stages increase. The shifted clocking technique is used to reduce the pipelined PA registers. The wave symmetry technique is applied to store (0: $\pi $/2) of the sine wave. The ROM is partitioned into three four-bit sub-ROMs based on the angular decomposition technique and trigonometric identity. A novel approach of memoryless ROM design technique is proposed and implemented in …
Robust Optimal Stabilization Of Balance Systems With Parametric Variations, Salman Zaffar, Attaullah Memon
Robust Optimal Stabilization Of Balance Systems With Parametric Variations, Salman Zaffar, Attaullah Memon
Turkish Journal of Electrical Engineering and Computer Sciences
This paper proposes a method of robust optimal stabilization for balance systems such as rocket and missile systems, Segway human transportation systems, and inverted pendulum systems. Constant-gain controllers such as linear-quadratic regulators may not guarantee stability let alone optimality for balance systems affected by parametric variations. The robust stability and robust performance achieved through the proposed variable-gain controller are better than those of the linear-quadratic regulator. The proposed controller consists of two components, one of which is designed offline for nominal values of parametric variations and one of which is updated online for off-nominal values of parametric variations. A salient …
Study And Analysis Of New Pulsed Electric Field Treatment Chamber Configurations For Food Extraction, Yassine Bellebna, Hamza Bermmaki, Abedelkader Semmak, Abdelkader Chaker, Amar Tilmatine
Study And Analysis Of New Pulsed Electric Field Treatment Chamber Configurations For Food Extraction, Yassine Bellebna, Hamza Bermmaki, Abedelkader Semmak, Abdelkader Chaker, Amar Tilmatine
Turkish Journal of Electrical Engineering and Computer Sciences
In all treatment chamber (TC) models used in industry and in research laboratories, the product to be treated is placed in one volume unit delimited between two electrodes energized by a pulsed voltage and the electric field lines are monoaxial and perpendicular to the electrodes. The objective of this paper is to perform an experimental analysis, based on the pulsed electric field-treated beet juice extraction efficiency, of two TC new configurations. The first model is constituted of one, two, or three parallel PEF units comprising several alternate ground-HV electrodes. The treatment chambers made of Plexiglas have a square parallelepipedic shape, …
An Ant Colony Optimization Algorithm-Based Classification For The Diagnosis Of Primary Headaches Using A Website Questionnaire Expert System, Ufuk Çeli̇k, Ni̇lüfer Yurtay
An Ant Colony Optimization Algorithm-Based Classification For The Diagnosis Of Primary Headaches Using A Website Questionnaire Expert System, Ufuk Çeli̇k, Ni̇lüfer Yurtay
Turkish Journal of Electrical Engineering and Computer Sciences
The purpose of this research was to evaluate the classification accuracy of the ant colony optimization algorithm for the diagnosis of primary headaches using a website questionnaire expert system that was completed by patients. This cross-sectional study was conducted in 850 headache patients who randomly applied to hospital from three cities in Turkey with the assistance of a neurologist in each city. The patients filled in a detailed web-based headache questionnaire. Finally, neurologists' diagnosis results were compared with the classification results of an ant colony optimization-based classification algorithm. The ant colony algorithm for diagnosis classified patients with 96.9412% overall accuracy. …
Sphere Decoding Algorithm For Multiuser Detection In A Distributed Antenna System, Fahad Khawaja, Alam Zaib, Shahid Khattak
Sphere Decoding Algorithm For Multiuser Detection In A Distributed Antenna System, Fahad Khawaja, Alam Zaib, Shahid Khattak
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, the impact of initial search radius on the complexity and performance of a sphere decoding algorithm is investigated for different user positions within a distributed antenna system. In a distributed antenna system, users can take up random positions within the cell clusters. The channel matrix can therefore take up infinitely different forms. In the presented work, a distributed antenna system with three different user positions in the cooperating cells is considered by employing different channel matrices. The effect on the complexity and performance of the sphere decoder due to the choice of the initial sphere radius is …
Creation Of A Dynamic Model Of The Electrification And Traction Power System Of A 25 Kv Ac Feed Railway Line Together With Analysis Of Different Operation Scenarios Using Matlab/Simulink, İlhan Kocaarslan, Mehmet Taci̇ddi̇n Akçay, Sirri Erdem Ulusoy, Emrah Bal, Hasan Ti̇ryaki̇
Creation Of A Dynamic Model Of The Electrification And Traction Power System Of A 25 Kv Ac Feed Railway Line Together With Analysis Of Different Operation Scenarios Using Matlab/Simulink, İlhan Kocaarslan, Mehmet Taci̇ddi̇n Akçay, Sirri Erdem Ulusoy, Emrah Bal, Hasan Ti̇ryaki̇
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, the simulation of an electrification system and traction power system of a 25 kV AC feed railway line was performed with all its subcomponents using MATLAB/Simulink. The power flow theory was used while modeling the railway electrification system. The transformer substation, catenary, rail, and vehicle were modeled together with the operational data. This model is used in order to determine the number of transformers, the distance of feeding centers, and the frequency of trips. The optimum design of electrification projects depends on these criteria. A dynamic structure was created with a new algorithm developed for vehicle load …
Investigation Of The Computational Speed Of Laguerre Network-Based Mpc In The Thermal Control Of Energy-Efficient Buildings, Ercan Atam
Turkish Journal of Electrical Engineering and Computer Sciences
The design of computationally efficient model predictive control (MPC) systems for the thermal control of buildings is a challenging task since long prediction horizons may be needed, which can take a significant computational time, especially when multizone buildings are considered. In this paper, we investigate the computational performance of a potential approach for this purpose, Laguerre network-based MPC (LN-MPC), for thermal control of buildings, where parameterization of control input over the prediction horizon is used to reduce the number of decision variables. The computational performance of the suggested framework with comparison to the classical MPC framework is investigated through a …
New Magnet Shape For Reducing Torque Ripple In An Outer-Rotor Permanent-Magnet Machine, Yusuf Özoğlu
New Magnet Shape For Reducing Torque Ripple In An Outer-Rotor Permanent-Magnet Machine, Yusuf Özoğlu
Turkish Journal of Electrical Engineering and Computer Sciences
Torque ripple is a major problem for permanent-magnet (PM) machines. It is examined by focusing on the magnetic circuit of the PM machine. Because there is a relationship between the torque ripple and the magnetic energy that is stored in the magnetic field along the air gap of the PM machine, a variation in the magnetic energy was revealed initially. A new magnet geometry is obtained by forming ledges and notches in the permanent magnets to modify the variation of the magnetic energy and the fluctuation in torque. Thus, a new PM design is proposed in this study to minimize …
Power Oscillation Damping Control By Pss And Dfig Wind Turbine Under Multiple Operating Conditions, Korakot Thanpisit, Issarachai Ngamroo
Power Oscillation Damping Control By Pss And Dfig Wind Turbine Under Multiple Operating Conditions, Korakot Thanpisit, Issarachai Ngamroo
Turkish Journal of Electrical Engineering and Computer Sciences
Multiple operating conditions in power systems including wind power sources significantly affect the damping of low frequency oscillation modes due to diverse generating and loading conditions, random wind speeds, line outage contingencies, etc. To cope with multiple operating conditions, this paper proposes the new parameter optimization technique of the power system stabilizer (PSS) and the doubly-fed induction generator (DFIG) wind turbine with the power oscillation damper (POD) based on the probability method. Different operating conditions are randomly generated by Monte Carlo simulation. Under the generated operating points, the particle swarm optimization of PSS and POD parameters is carried out to …
Design Of Adjustable T-Shaped And Y-Shaped Photonic Crystal Power Splitters For Tm And Te Polarizations, Mohammad Danaie, Ruhllah Nasirifar, Abbas Dideban
Design Of Adjustable T-Shaped And Y-Shaped Photonic Crystal Power Splitters For Tm And Te Polarizations, Mohammad Danaie, Ruhllah Nasirifar, Abbas Dideban
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, new topologies for realization of photonic crystal optical power splitters for TE and TM modes are proposed. The presented structures can be used for dividing input power with a desired ratio to output ports. The central input wavelength is designed for 1550 nm. To obtain wide-bandwidth power splitters for TE and TM modes, modified Y-shaped and T-shaped photonic crystal junctions are used. A triangular lattice of air holes and a square lattice of rods are used for Y-shaped and T-shaped platforms, respectively. For analyzing these structures, plane wave expansion and finite difference time domain methods are used. …
Discrete Design Optimization Of Distribution Transformers With Guaranteed Optimum Convergence Using The Cuckoo Search Algorithm, Levent Alhan, Nejat Yumuşak
Discrete Design Optimization Of Distribution Transformers With Guaranteed Optimum Convergence Using The Cuckoo Search Algorithm, Levent Alhan, Nejat Yumuşak
Turkish Journal of Electrical Engineering and Computer Sciences
Transformer design optimization methods presented in the literature rarely yield solutions directly applicable in production; the design engineer usually needs to convert the theoretical solution to a practical one. This problem is addressed in this paper, and a discrete transformer design optimization method is proposed that yields solutions with commercially available or productionally feasible dimensions, thus eliminating the need for further efforts of the design engineer to make the theoretical solution a feasible one. The cuckoo search, a nature-inspired metaheuristic algorithm, is used as the optimization algorithm in this study, and it is shown that the guaranteed global optimum solution …
A Novel And Realistic Hybrid Downlink-Uplink Coupled/Decoupled Access Scheme For 5g Hetnets, Nadeem Sial, Junaid Ahmed
A Novel And Realistic Hybrid Downlink-Uplink Coupled/Decoupled Access Scheme For 5g Hetnets, Nadeem Sial, Junaid Ahmed
Turkish Journal of Electrical Engineering and Computer Sciences
Cell association in present day heterogeneous networks (HetNets) is still based on the technique used by homogeneous cellular networks despite power and coverage area disparities of network nodes. In ongoing policy, both uplink (UL) and downlink (DL) associations are coupled based on DL characteristics, which introduces UL-DL asymmetry and cell load imbalances. Recently, decoupled cell association, also known as downlink-uplink decoupling (DUDe), has been introduced in 3rd Generation Partnership Project (3GPP) Release 12 to improve uplink performance, load balancing, and cell capacity. In DUDe, characteristics of both DL and UL channels can be considered. By using this concept, various theoretical …
Lifetime Maximization Of Wireless Sensor Networks With Sink Costs, Muhammed Emre Keski̇n
Lifetime Maximization Of Wireless Sensor Networks With Sink Costs, Muhammed Emre Keski̇n
Turkish Journal of Electrical Engineering and Computer Sciences
Balanced distribution of the energy load of the sensors is important for the elongation of wireless sensor network (WSN) lifetimes. There are four main WSN design issues affecting the energy distribution among the sensors: sensor locations, sensor activity schedules, mobile sink routes, and data flow routes. Many studies try to make energy usage more efficient through optimal determination of these design issues. However, only very few studies handle these four design issues in a combined manner. Additionally, the cost of the sinks is neglected in all studies. In this study, a mixed integer linear program is first proposed, in which …
Markovian Model For Reliability Assessment Of Microgrids Considering Load Transfer Restriction, Mohammad Almuhaini, Abdulrahman Al-Sakkaf
Markovian Model For Reliability Assessment Of Microgrids Considering Load Transfer Restriction, Mohammad Almuhaini, Abdulrahman Al-Sakkaf
Turkish Journal of Electrical Engineering and Computer Sciences
Reliability is an indispensable factor in power system design and operation and has a significant impact on grid safety and economy. Future power distribution systems are expected to be more sophisticated, owing to the increasing penetration of renewable resources and adoption of advanced information and communication technologies. Extant studies in this field tend to focus on the modeling and assessment of the reliability of future microgrid distribution systems, including distributed generation, without considering networked configuration and limited transfer capacity. In the work presented in this paper, a Markov model is implemented to perform a practical and accurate reliability evaluation of …
Optimal Reactive Power Flow In Bdfms For Converter Cost Reduction And Efficiency Improvement, Behzad Jandaghi, Hamed Gorginpour, Mohammad Naser Hashemnia, Hashem Oraee
Optimal Reactive Power Flow In Bdfms For Converter Cost Reduction And Efficiency Improvement, Behzad Jandaghi, Hamed Gorginpour, Mohammad Naser Hashemnia, Hashem Oraee
Turkish Journal of Electrical Engineering and Computer Sciences
A brushless doubly fed machine is equipped with two decoupled windings on its stator, known as the power winding and the control winding. The power winding reactive power can be controlled by voltage amplitude fed by the machine-side converter to the control winding, affecting both the converter size and machine efficiency. This paper investigates different proposed scenarios for optimal reactive power flow targeted to minimize the converter cost and maximize the machine efficiency. Previously, the grid-side converter has not been used for reactive power compensation. However, in the present paper it is shown how the grid-side converter can be effectively …
Calculation Of Current Limiting Reactance Of Hybrid Sfcl For Low Voltage Ride-Through Capability Enhancement In Dfig Wind Farms, Sillawat Romphochai, Komsan Hongesombut
Calculation Of Current Limiting Reactance Of Hybrid Sfcl For Low Voltage Ride-Through Capability Enhancement In Dfig Wind Farms, Sillawat Romphochai, Komsan Hongesombut
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a new approach for the low voltage ride-through capability enhancement of doubly-fed induction generator (DFIG) wind farms using a hybrid superconducting fault current limiter (SFCL) of the first peak current limiting type, which has the advantage of a fast recovery time. A design for the hybrid SFCL, focusing on current limiting reactor (CLR) reactance calculation, is proposed in this paper to determine an appropriate value for the CLR reactance that satisfies the grid code requirements of the DFIG wind turbines. High-temperature superconductors (HTS) such as Bi-2212, YBCO, Bi-2223, Ti-2223, and Hg-1223 are investigated for use in the …
Low Complexity Link Level Performance Prediction For Simo Systems, Asif Khan, Alam Zaib, Shahid Khattak
Low Complexity Link Level Performance Prediction For Simo Systems, Asif Khan, Alam Zaib, Shahid Khattak
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper a low-cost link level performance prediction technique is proposed for a single input and multiple output system. Receiver link level abstraction is used in system level simulations of large networks in order to reduce their complexity. Usually, a single lookup table is employed in link level abstraction to predict a receiver's performance under different channel conditions. In the presented work, the mean frame error rate curve of different diverse channels is proposed as the reference for performance prediction in single input multiple output systems. Its generation involves compression of the received code word into a single quality …