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Full-Text Articles in Computer Engineering

Optimal Release Policies For A Software System With Warranty Cost And Change-Point Phenomenon, D.R. Prince Williams Jan 2013

Optimal Release Policies For A Software System With Warranty Cost And Change-Point Phenomenon, D.R. Prince Williams

Turkish Journal of Electrical Engineering and Computer Sciences

Determining the software quality and release time of the software is an important role of software reliability. Software reliability growth models (SRGMs) are applications of software reliability. The change-point is defined as the prominent change in the software testing time, in connection with the quality of a software error occurrence or error-detection phenomenon. As a result, the software reliability growth process, based on the change-point, affects the precision of the software reliability prediction, based on the SRGMs. To find the accurate total expected delivery cost with a suitable warranty period of the software system, a new cost model for the …


Novel Control Strategy For Voltage Source Converters Based On Energy Function, Sanaz Namayan Tavana, Gevork Gharehpetian, Mehrdad Abedi, Ali Bidadfar Jan 2013

Novel Control Strategy For Voltage Source Converters Based On Energy Function, Sanaz Namayan Tavana, Gevork Gharehpetian, Mehrdad Abedi, Ali Bidadfar

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes a nonlinear control strategy for pulse-width modulated voltage source converters (VSCs). A passivity-based approach, resulting from the Lyapunov direct method, is presented for designing an effective nonlinear VSC controller to improve their dynamic behaviors under perturbed conditions. The differential equations of the converters are obtained and then transformed into a d-q frame. Considering the nonlinearity of the transformed equations, the Lyapunov direct method is utilized to find a solution to improve the transient response. The time derivative of the Lyapunov function guarantees that increasing its dissipative term will result in the trajectory of the VSC system returning …


Adaptive Control Of A Time-Varying Rotary Servo System Using A Fuzzy Model Reference Learning Controller With Variable Adaptation Gain, Ömer Aydoğdu, Özdemi̇r Alkan Jan 2013

Adaptive Control Of A Time-Varying Rotary Servo System Using A Fuzzy Model Reference Learning Controller With Variable Adaptation Gain, Ömer Aydoğdu, Özdemi̇r Alkan

Turkish Journal of Electrical Engineering and Computer Sciences

The constant parameters in a conventional fuzzy controller lead to a poor performance for time-varying systems. In this study, a fuzzy model reference learning controller (FMRLC) with a newly defined variable adaptation gain is designed and implemented in the adaptive fuzzy control of a time-varying rotary servo (TVRS) system. In the design of the FMRLC, a knowledge-base modification algorithm with variable adaptation gain is used instead of a fuzzy relation table. Hence, it is provided that the learning and adaptation mechanism continuously updates the knowledge base of the adaptive fuzzy controller against any parameter variations, such as changing loads. By …


Optimized Operation And Maintenance Costs To Improve System Reliability By Decreasing The Failure Rate Of Distribution Lines, Hamed Hashemi Dezaki, Seyed Hossein Hosseinian, Hossein Askarian Abyaneh, Seyed Mohammad Mousavi Agah Jan 2013

Optimized Operation And Maintenance Costs To Improve System Reliability By Decreasing The Failure Rate Of Distribution Lines, Hamed Hashemi Dezaki, Seyed Hossein Hosseinian, Hossein Askarian Abyaneh, Seyed Mohammad Mousavi Agah

Turkish Journal of Electrical Engineering and Computer Sciences

Improving distribution system reliability has received a great deal of attention in recent years. Because of the limitation in expected budgets, it is desirable to determine the most efficient strategy to improve system reliability. This paper proposes a novel method to determine the optimized operation and maintenance costs in order to decrease the failure of system components. The proposed objective function includes the average system frequency interruption index (ASIFI) value. To achieve the best strategy to decrease failures of system components, it is necessary to find the minimum value of the objective function, considering the constraints of operation and maintenance …


Model Of A Photovoltaic Panel Emulator In Matlab-Simulink, Hayretti̇n Can Jan 2013

Model Of A Photovoltaic Panel Emulator In Matlab-Simulink, Hayretti̇n Can

Turkish Journal of Electrical Engineering and Computer Sciences

Being able to behave electrically similar to photovoltaic (PV) panels, PV emulator systems make it possible to perform different PV system tests under various operation conditions. In this paper, a model of a PV panel emulator is presented using the Power System Blockset under MATLAB-Simulink. The simulation of the emulator system is developed for testing a controller prior to a real-time implementation. The model can handle the dependence of all of the parameters in the model with respect to solar radiation and temperature. The simulation results show that the output characteristics of the simulator have good agreement with those of …


The Vortex Effect Of Francis Turbine In Electric Power Generation, Veli̇ Türkmenoğlu Jan 2013

The Vortex Effect Of Francis Turbine In Electric Power Generation, Veli̇ Türkmenoğlu

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, the vibration effects of a vortex that occurred in high-head Francis turbines and an alternator are examined. The vortex effect, which directly affects the efficiency and the quality of the energy, was tested at the DarÔøΩca-1 hydroelectric power plant (HPP) located in Ordu Province, Turkey. Formed by undissolved oxygen in the water, the vortex effect, which is parallel to the alternator load, causes tremendous vibration within the alternator and Francis turbine bearings. This problem, which has a direct negative effect on the alternator capacity, was solved by adding an air-admission system. In doing so, power production was …


A Practical Disturbance Generator To Test Performances Of Various Power Quality Mitigation Devices, Ahmet Teke, Mehmet Emi̇n Meral, Mehmet Tümay, Mehmet Uğraş Cuma Jan 2013

A Practical Disturbance Generator To Test Performances Of Various Power Quality Mitigation Devices, Ahmet Teke, Mehmet Emi̇n Meral, Mehmet Tümay, Mehmet Uğraş Cuma

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a practical thyristor-based 3-phase sag/swell/outage generator (disturbance generator) is designed to test various power quality mitigation devices (PQMDs), such as solid state transfer switch (SSTS), static voltage compensator (SVC), and uninterruptible power supply. The latest technological disturbance generators (DGs) and the proposed DG are comprehensively discussed and compared with focus on usefulness, economic aspects, and simplicity. The proposed DG is used for experimentally generating different fault conditions and testing a SSTS. The comparisons and analyses show that the proposed DG is an optimum and simple solution to generate sag, swell, unbalance, overvoltage, undervoltage, and outage to test …


Circulating Current Analysis Between Strands In Armature Winding Of A Turbo-Generator Using Analytical Model, Karim Abbaszadeh, Farhad Rezaee Alam Jan 2013

Circulating Current Analysis Between Strands In Armature Winding Of A Turbo-Generator Using Analytical Model, Karim Abbaszadeh, Farhad Rezaee Alam

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, the circulating current analysis between strands is studied while considering the different transpositions in the active part and without considering the transposition in the end winding region. First, this analysis is done while only considering the slot region, and then the end winding region is added to the model. The model used for this analysis is a circuit model, including the resistance and inductance of the strands and their induced back-electromotive force (EMF). The back-EMF sources and inductances are calculated through a 2D finite element analysis (FEA) of the active part and a 3D FEA for the …


A Novel Multirobot Map Fusion Strategy For Occupancy Grid Maps, Sebahatti̇n Topal, İsmet Erkmen, Aydan Müşerref Erkmen Jan 2013

A Novel Multirobot Map Fusion Strategy For Occupancy Grid Maps, Sebahatti̇n Topal, İsmet Erkmen, Aydan Müşerref Erkmen

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we consider the problem of merging partial occupancy grid environment maps, which are extracted independently by individual robot units during search and rescue (SAR) operations in icomplex disaster environments. Moreover, these maps are combined using intensity-based and area-based features without knowing the initial position and orientation of the robots. Our proposed approach handles the limitation of existing studies in the literature; for example, the limited overlapped area between partial maps of robots is enough for good merging performance and unstructured and complex partial environment maps can be merged efficiently. These abilities allow multirobot teams to efficiently generate …


Pc-Based Data Acquisition System For Plc-Controlled Linear Switched Reluctance Motor, Mahi̇r Dursun, Semi̇h Özden Jan 2013

Pc-Based Data Acquisition System For Plc-Controlled Linear Switched Reluctance Motor, Mahi̇r Dursun, Semi̇h Özden

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, a linear switched reluctance motor (LSRM) with 250 W, 6/4 poles, 3 phases, and 24 V was controlled with a programmable logic controller (PLC). Some parameters of the LSRM were set, and for PC monitoring, software developed by the authors was used. A serial port was used for communication between the PC and the PLC. The software was developed with Visual C#.Net 2008 for monitoring and controlling. This user interference allows for controlling of the motor's travelling distance with a running strategy. The first and second destination can be defined and the system provides that the motor …


The Development Of A Hardware- And Software-Based Simulation Platform For The Training Of Driver Candidates, Abdullah Çavuşoğlu, İsmai̇l Kurnaz Jan 2013

The Development Of A Hardware- And Software-Based Simulation Platform For The Training Of Driver Candidates, Abdullah Çavuşoğlu, İsmai̇l Kurnaz

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, a traffic simulation system (TSS) to provide novice driver candidates with opportunities for training and testing has been developed. Autonomous vehicles that follow the flow of traffic in a microsimulation environment were prepared using a hierarchical concurrent state machine. Autonomous vehicles are skilled and have behavioral aspects such as tracking the lanes, following the vehicles, complying with traffic rules, decelerating, accelerating, and intersection crossings. These driver behaviors are parameterized to allow the autonomous agents to act while disregarding the rules (i.e. aggressive behaviors) or behaving normally. The TSS is operated in 3 different modes, namely the orientation, …


Spatiotemporal Model Checking Of Location And Mobility Related Security Policy Specifications, Devri̇m Ünal, Mehmet Ufuk Çağlayan Jan 2013

Spatiotemporal Model Checking Of Location And Mobility Related Security Policy Specifications, Devri̇m Ünal, Mehmet Ufuk Çağlayan

Turkish Journal of Electrical Engineering and Computer Sciences

For the formal verification of security in mobile networks, a requirement is that security policies associated with mobility and location constraints are formally specified and verified. For the formal specification and verification of security policies, formal methods ensure that a given network configuration that includes certain network elements satisfies a given security policy. A process calculus based approach is presented, where ambient calculus is used for formal specification of security policies and ambient logic is used for formal representation of mobility and location constraints. A spatiotemporal model checking algorithm is presented for the model checking of formal specifications in ambient …


Current-Mode Quadrature Oscillator Based On Cccdtas With Noninteractive Dual-Current Control For Both Condition Of Oscillation And Frequency Of Oscillation, Adirek Jantakun, Winai Jaikla Jan 2013

Current-Mode Quadrature Oscillator Based On Cccdtas With Noninteractive Dual-Current Control For Both Condition Of Oscillation And Frequency Of Oscillation, Adirek Jantakun, Winai Jaikla

Turkish Journal of Electrical Engineering and Computer Sciences

The realization of 2 current-mode quadrature oscillators using current-controlled current differencing transconductance amplifiers (CCCDTAs) and grounded capacitors is presented. The proposed oscillators can provide 2 sinusoidal output currents with a 90° phase difference. They enable noninteractive dual-current control for both the condition of oscillation and the frequency ofi oscillation. The high-output impedances of the configurations enable the circuit to be cascaded without additional current buffers. The use of only grounded capacitors is ideal for integration. The circuit performances are depicted through PSpice simulations; they show good agreement to theoretical anticipation.


A Time--Memory Trade-Off Approach For The Solution Of Nonlinear Equation Systems, Hüseyi̇n Demi̇rci̇, Mahmut Şami̇l Sağiroğlu, Muhammed Oğuzhan Külekci̇ Jan 2013

A Time--Memory Trade-Off Approach For The Solution Of Nonlinear Equation Systems, Hüseyi̇n Demi̇rci̇, Mahmut Şami̇l Sağiroğlu, Muhammed Oğuzhan Külekci̇

Turkish Journal of Electrical Engineering and Computer Sciences

We propose a memory-based method for the solution of a specific type of nonlinear equation systems. We observe that when the equations in a system can be separated into 2 parts, where each subset contains fewer parameters than the whole set of equations, the system can be solved faster with a preprocessing phase. We show that reduced rounds of AES produce such a system under a chosen plaintext scenario. This observation enables us to solve that system within a practically applicable complexity of 2^{37} operations where a brute force approach requires 2^{72} trials. The method can be used for the …


Orthogonal Array Based Performance Improvement In The Gravitational Search Algorithm, Ökkeş Tolga Altinöz, Asim Egemen Yilmaz, Gerhard Wilhelm Weber Jan 2013

Orthogonal Array Based Performance Improvement In The Gravitational Search Algorithm, Ökkeş Tolga Altinöz, Asim Egemen Yilmaz, Gerhard Wilhelm Weber

Turkish Journal of Electrical Engineering and Computer Sciences

The gravitational search algorithm (GSA) is a novel heuristic method inspired by Newton's gravity and velocity equations. In addition, it is a population-based algorithm, in which each member (called an agent) in the population has a mass, velocity, and acceleration. Beginning with the first population state, agents influence each other via mass and velocity relations. This mutual effect causes agents to reach the optimum. Hence, the performance of the GSA to attain the optimum is related to the initial population formation, like other population-based algorithms. In this study, the orthogonal array (OA) concept is applied and injected to the GSA …


Control In Networked Systems With Fuzzy Logic, Akhan Akbulut, Oğuzhan Öztaş Jan 2013

Control In Networked Systems With Fuzzy Logic, Akhan Akbulut, Oğuzhan Öztaş

Turkish Journal of Electrical Engineering and Computer Sciences

Recently, the development of control systems based on network-based architecture is getting very high attention. Because of its fast data communication, network-based control is in high demand. However, there are some disadvantages, such as delays, data packet dropouts, and communication constraints. Network-based control systems are getting attention in the development of this architecture because of these disadvantages. Optimization of the system is supplied to improve the existing structure. The optimization is categorized into 2 main structures: software optimization and hardware optimization. The structure of the overall system is designed with these optimization strategies. A hierarchical and communicational structure has emerged …


Solution To The Unit Commitment Problem Using An Artificial Neural Network, Mehdi Zareian Jahromi, Mohammad Mehdi Hosseini Bioki, Masoud Rashidi Nejad, Roohollah Fadaeinedjad Jan 2013

Solution To The Unit Commitment Problem Using An Artificial Neural Network, Mehdi Zareian Jahromi, Mohammad Mehdi Hosseini Bioki, Masoud Rashidi Nejad, Roohollah Fadaeinedjad

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes a real-time solution to the unit commitment problem by considering different constraints like ramp-up rate, unit operation emissions, next hours load, and minimum down time. In this method, an optimized trade-off between cost and emission has been taken into consideration. The effectiveness of the proposed method was verified by the significant outcomes demonstrated.


A Comparative Study In Power Oscillation Damping By Statcom And Sssc Based On The Multiobjective Pso Algorithm, Ali Ajami, Mehdi Armaghan Jan 2013

A Comparative Study In Power Oscillation Damping By Statcom And Sssc Based On The Multiobjective Pso Algorithm, Ali Ajami, Mehdi Armaghan

Turkish Journal of Electrical Engineering and Computer Sciences

To improve the damping of power system oscillations by supplementary controller design for the static synchronous series compensator (SSSC) and static synchronous compensator (STATCOM), a multiobjective function based on the particle swarm optimization (PSO) algorithm for solving this optimization problem is introduced. The presented objective function includes the damping factor and the damping ratio of the lightly damped and undamped electromechanical modes. These controllers are adjusted to concurrently transfer the lightly damped and undamped electromechanical modes to a recommended region in the s-plane. For this purpose, the reduced linearized Phillips-Heffron model of the power system with a single machine and …


Exergoeconomic Analysis Of A Solar Photovoltaic System In İstanbul, Turkey, Ercan İzgi̇, Yunus Emre Akkaya Jan 2013

Exergoeconomic Analysis Of A Solar Photovoltaic System In İstanbul, Turkey, Ercan İzgi̇, Yunus Emre Akkaya

Turkish Journal of Electrical Engineering and Computer Sciences

This paper deals with the exergoeconomic analysis of a 750-Wp solar photovoltaic (PV) system that is constructed at the Meteorology Park of İstanbul Technical University (41.102° N, 29.02° E) in İstanbul, Turkey. It is known that seasonal differences cause a variation in the exergoeconomic parameters (energy and exergy loss rates) of solar PV systems. Due to this perspective, for regional climatic parameters 2 months are selected: April to represent the spring and August to represent the summer. Within this research, first the exergy analysis is performed on the system and then the economic values of the results are evaluated using …


Symbol Detection Using The Differential Evolution Algorithm In Mimo-Ofdm Systems, Muhammet Nuri̇ Seyman, Necmi̇ Taşpinar Jan 2013

Symbol Detection Using The Differential Evolution Algorithm In Mimo-Ofdm Systems, Muhammet Nuri̇ Seyman, Necmi̇ Taşpinar

Turkish Journal of Electrical Engineering and Computer Sciences

Channel estimation and symbol detection in multiple-input and multiple-output (MIMO)-orthogonal frequency division multiplexing (OFDM) systems are essential tasks. Although the maximum likelihood (ML) detector reveals excellent performance for symbol detection, the computational complexity of this algorithm is extremely high in systems with more transmitter antennas and high-order constellation size. In this paper, we propose the differential evolution (DE) algorithm in order to reduce the search space of the ML detector and the computational complexity of symbol detection in MIMO-OFDM systems. The DE algorithm is also compared to some heuristic approaches, such as the genetic algorithm and particle swarm optimization. According …


Stability Analysis Of Time-Delayed Dc Motor Speed Control System, Saffet Ayasun Jan 2013

Stability Analysis Of Time-Delayed Dc Motor Speed Control System, Saffet Ayasun

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, the stability of time-delayed DC motor speed control systems is analyzed. The measurement devices and communication links used by networked control systems, cause a significant amount of time delays. The stability boundary of the system in terms of the time delay is theoretically determined and an expression is obtained to compute the delay margin in terms of system parameters. The delay margin is defined as the maximum amount of time delay for which the DC motor speed control system is marginally stable. The results indicate that the system becomes unstable if the time delay exceeds the delay …


An Automotive Vehicle Dynamics Prototyping Platform Based On A Remote Control Model Car, Seli̇m Solmaz, Türker Coşkun Jan 2013

An Automotive Vehicle Dynamics Prototyping Platform Based On A Remote Control Model Car, Seli̇m Solmaz, Türker Coşkun

Turkish Journal of Electrical Engineering and Computer Sciences

The use of a modified remote control (RC) model car as a vehicle dynamics testing and development platform is detailed. Vehicle dynamics testing is an important aspect of automotive engineering and it plays a key role during the design and tuning of active safety control systems. Considering the fact that such tests are conductedi at great expense, scaled model cars can potentially be used to help with the process to reduce the costs. With this view, we instrument and develop a standard electric RC model car into a vehicle dynamics testing platform. We then implement 2 representative active safety control …


Design Of Adaptive Compensators For The Control Of Robot Manipulators Robust To Unknown Structured And Unstructured Parameters, Recep Burkan Jan 2013

Design Of Adaptive Compensators For The Control Of Robot Manipulators Robust To Unknown Structured And Unstructured Parameters, Recep Burkan

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a new adaptive-robust control approach for robot manipulators is developed. The adaptive-robust control law is not only robust to unknown structured parameters but also robust to unknown unstructured parameters such as unstructured joint friction and disturbances. The bounded disturbances and unstructured model are taken into account in a dynamic model and it is assumed that the structured and unstructured parameters are unknown. The structured and unstructured parameters are distinguished between parameters and these parameters are treated separately. Next, new parameter estimation functions are developed for each of the 2 uncertainty groups. After that, the developed dynamic adaptive …


Design And Evaluation Of Schemes For Computing Sum Of Squares In Fixed Point, Meti̇n Mete Özbi̇len, Milos D. Ercegovac Jan 2013

Design And Evaluation Of Schemes For Computing Sum Of Squares In Fixed Point, Meti̇n Mete Özbi̇len, Milos D. Ercegovac

Turkish Journal of Electrical Engineering and Computer Sciences

Several schemes for computing the sum of squares for fixed point numbers are designed, synthesized, and evaluated in this study. The schemes use radix-2 folding, radix-4 folding, and radix-4 dual recoding approaches for squaring. The schemes have been modeled in hardware description language, simulated, and synthesized using Cadence SOC81 in 45 nm and 90 nm libraries and with Mentor Graphics Leonardo Spectrum for 180 nm. We show delay and area for 16-, 24-, and 32-bit operands. After hard-wire and software optimizations, it is seen that schemes with radix-4 give better results, especially in area.


Eetbr: Energy Efficient Token-Based Routing For Wireless Sensor Networks, Taner Çevi̇k, Abdül Hali̇m Zai̇m Jan 2013

Eetbr: Energy Efficient Token-Based Routing For Wireless Sensor Networks, Taner Çevi̇k, Abdül Hali̇m Zai̇m

Turkish Journal of Electrical Engineering and Computer Sciences

The most significant drawback of wireless sensor networks is energy scarcity. As there is an increasing need for operating these networks for relatively long times, energy saving becomes the key challenge in the design of the architectures and protocols for sensor networks. Therefore, several research studies have been performed for making contributions to the analysis of this energy shortage problem. Most of these research activities have been focused on finding solutions for the energy consumption of the communication unit, which is the dominant energy dissipating component of the sensor nodes. In this paper, a novel, token-based routing protocol adapted with …


Performance Analysis Of Bid Calculation Methods In Multirobot Market-Based Task Allocation, Burak Kaleci̇, Osman Parlaktuna Jan 2013

Performance Analysis Of Bid Calculation Methods In Multirobot Market-Based Task Allocation, Burak Kaleci̇, Osman Parlaktuna

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, the empirical results of a market-based task allocation method for heterogeneous and homogeneous robot teams and different types of tasks in 2 different environments are presented. The proposed method allocates robots to tasks through a parallel multiitem auction-based process. The main contribution of the proposed method is energy-based bid calculations, which take into account both the heterogeneity of the robot team and features of the tasks. The multirobot task allocation problem is considered as the optimal assignment problem and the Hungarian algorithm is used to clear the auctions. Simulations are carried out using energy-based, distance-based, and time-based …


A New Digital Image Steganography Algorithm Based On Visible Wavelength, İbrahi̇m Coşkun, Feyzi̇ Akar, Özdemi̇r Çeti̇n Jan 2013

A New Digital Image Steganography Algorithm Based On Visible Wavelength, İbrahi̇m Coşkun, Feyzi̇ Akar, Özdemi̇r Çeti̇n

Turkish Journal of Electrical Engineering and Computer Sciences

Stenography is the science that ensures secret communication through multimedia carriers such as image, audio, and video files. The ultimate end of stenography is to hide the secret data in the carrier file so that they are not detected. To that end, stenography applications should have such features as undetectability; robustness; resistance to various images process, sing methods, and compression; and capacity of the hidden data. At the same time, those features distinguish stenography applications from watermarking and cryptography applications. This study is different from other studies in the literature in that the undetectability parameter has been achieved through hiding …


A New Color Image Quality Measure Based On Yuv Transformation And Psnr For Human Vision System, Yildiray Yalman, İsmai̇l Ertürk Jan 2013

A New Color Image Quality Measure Based On Yuv Transformation And Psnr For Human Vision System, Yildiray Yalman, İsmai̇l Ertürk

Turkish Journal of Electrical Engineering and Computer Sciences

Various methods for measuring perceptual image quality attempt to quantify the visibility of differences between an original digital image and its distorted version using a variety of known properties of the human vision system (HVS). In this paper, we propose a simple and effective full-reference color image quality measure (CQM) based on reversible luminance and chrominance (YUV) color transformation and peak signal-to-noise ratio (PSNR) measure. The main motivation of this new measure relies on a unique feature of the human eye response to the luminance and color. Experimental studies about the applicability of the CQM on a well-known test image …


Chaos Control Of Single Time-Scale Brushless Dc Motor With Sliding Mode Control Method, Yilmaz Uyaroğlu, Bariş Cevher Jan 2013

Chaos Control Of Single Time-Scale Brushless Dc Motor With Sliding Mode Control Method, Yilmaz Uyaroğlu, Bariş Cevher

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, the sliding mode control (SMC) scheme of single time-scale brushless DC motor (BLDCM) is investigated. The SMC method consists of 2 sections. To simplify the directive of the stability of the controlled single time-scale BLDCM in the sliding mode, first a special type of PI switching surface is adopted. Second, the SMC controller is obtained to guarantee the occurrence of the PI switching surface. The effectiveness of the theoretical analysis is evaluated by numerical simulations. Thus, the numerical results are used to show the verification and trustworthiness of the proposed method.


A Novel Approach For The Reconfiguration Of Distribution Systems Considering The Voltage Stability Margin, Mohammad Hasan Hemmatpour, Mohsen Mohammadian, Mohsen Rezaie Estabragh Jan 2013

A Novel Approach For The Reconfiguration Of Distribution Systems Considering The Voltage Stability Margin, Mohammad Hasan Hemmatpour, Mohsen Mohammadian, Mohsen Rezaie Estabragh

Turkish Journal of Electrical Engineering and Computer Sciences

In recent years, the problem of optimum reconfiguration in distribution systems (DSs) has been a task that must be solved in an optimal manner. This paper presents a new approach for the optimal reconfiguration of DSs based on a hierarchical 2-stage optimization problem to improve the power system voltage stability margin and reduce losses incorporating the constraints. The mentioned problem has been modeled as a nonlinear and multiobjective optimization problem. It uses the ability of the developed harmony search algorithm (HSA) as the first stage of the proposed optimization problem to reach the best network configuration. This reconfiguration algorithm starts …