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Öğe Exploring the Effect of Distribution Methods on Meta-Heuristic Searching process(Ieee, 2017) Kahraman, Hamdi Tolga; Aras, Sefa; Güvenç, Uğur; Sönmez, YusufIn this study, the effect of distributions of solution candidates on the problem space in the meta-heuristic search process and the performance of algorithms has been investigated. For this purpose, solution candidates have been created with random and gauss (normal) distributions. Search performance is measured separately for both types of distribution of algorithms. The performances of the algorithms have been tested on the most popular and widely used benchmark problems. Experimental studies have been conducted on the most recent meta-heuristic search algorithms. It has been seen that the search performance of algorithms varies considerably depending on the method of distribution. In fact, better results were obtained than the distribution methods used in the original versions of the algorithms. Algorithms have revealed their abilities in terms of neighborhoods searching, getting rid of local minimum traps and speeding up searches.Öğe Developing an CNC lathe augmented reality application for industrial maintanance training(Ieee, 2018) Güler, Osman; Yücedağ, İbrahimIn this study, developing an augmented reality training application for CNC (computer numerical control) lathe looms for industrial maintenance and repair training was described. The content has been developed for the CNC LATHE TEARS module, which is trained in the field of Machine Technologies to be operated on mobile like smart phone, tablet, etc. devices. First a training scenario was prepared for the development of the application. Then three dimensional model of a CNC lathe was modelled. Models designed to develop the augmented reality application have been transferred to the Unity3D game engine software, and using the Vuforia plug-in, a marker-based augmented reality application has been developed to work on android operating system based mobile devices like smartphone, tablet, etc. It is considered that using the developed application in the training of the students of the Machine Technologies Area in the institutions providing vocational and technical education in the official and private institutions affiliated to the Ministry of National Education, motivation of the students and the success rates of the courses will increase. At the same time, the developed application will provide facilitate the training of the users, increase the quality in production and faster maintenance and installation.Öğe Current Ripple Minimization of a PEM Fuel Cell via an Interleaved Converter to Prolong the Stack Life(Ieee, 2016) Yıldız, Emre; Vural, Bülent; Akar, FurkanThis paper focuses on to prolong the Proton Exchange Membrane (PEM) fuel cell stack life via an interleaved double switch buck-boost converter. PEM fuel cells are environmental friendly energy sources, and widely used in several applications such as electrical vehicles, power plants, back-up power units, thanks to their fast start-up ability, portability, and efficient operation. In the steady-state, the fuel cell current ripple may result in damage to the fuel cell chemical structure, so it is required to extract its power via a power converter that can overcome this issue. Therefore, in this work, a power converter topology and a control method are proposed in order to reduce the converter input current ripple in both buck and boost operation modes with the help of its two input inductors. In addition to that, sharing input current via these inductors decreases input capacitance voltage stresses and average current flowing through the interleaved inductors thus smaller input capacitance and inductors also increase the cost effectiveness of proposed converter. The simulation results indicate that the proposed interleaved buck-boost topology reduces the input current ripple, and leads less settling time hence better dynamic response owing to its interleaved structure.Öğe Use of Multifunctional Power Electronic Network Controllers in Smart Distribution Systems(Ieee, 2014) Kale, Murat; Hauer, Ines; Kruschel, Wolfram; Maurer, Tobias; Zacharias, PeterDiverse and dynamic load and generation patterns are putting new demands on the operation of distribution networks. New network management approaches and innovative equipment are needed to handle highly volatile voltage profiles resulting from intermittent distributed generation. This paper investigates the use of an inline voltage regulator in a LV network. As simulations based on realistic feed-in scenarios show, it is an efficient tool for influencing a network's voltage profile. Since voltage regulation is not required permanently, such a flexible power electronic device can be further used to increase a power system's efficiency and reliability by implementing features such as reactive power compensation or mitigation of harmonics. Concerning this matter, an approach for an adaptive system management is discussed that allows the provision of additional functionality whenever the converter is not used to its full capacity for the voltage regulation task.Öğe LCL Filter Design for Grid Connected Three-Phase Inverter(Ieee, 2018) Dursun, Mustafa; Döşoğlu, M. KenanIn this study, LCL filter design was performed by simulating and theoretical analysis detail of a grid-connected system in MATLAB / Simulink environment. Inverters connected to the grid, filter is required as an interface between the inverter and the electric grid. The most effective filter for suppressing of the current harmonics occurring from the switching frequency injected into the grid is the LCL filter. The LCL filter must be designed appropriately to achieve high quality grid currents. LCL parameters are calculated for synchronized operation of the converter and grid. Simulation results were shown that, the LCL filter designed for harmonics has decreased in high degree harmonics in inverter output.Öğe Control of DC link Voltage Unit with Fuzzy Logic Controller in the Wind Farm(Ieee, 2013) Döşoğlu, Mehmet Kenan; Poyraz, Gökhan; Dursun, Mustafa; Öztürk, AliIn this study, the analysis of wind farm that has Double Feed Induction Generator (DFIG) with Fuzzy Logic Controller (FLC) in its operation connected to the grid is realized. In wind farm, DC voltage control is modeled with FLC. Bus voltages that are connected to grid, load bus voltage, DC link voltage, active and reactive power variations of wind farm are examined. Simulation results are demonstrated with figures by Fuzzy Logic Controller (FLC)-Proportion Integrate (PI) comparison. As a result of the studies, it is observed that FLC makes the system stable in a shorter time than PI.Öğe Battery/UC Hybridization for Electric Vehicles via a Novel Double Input DC/DC Power Converter(Ieee, 2013) Akar, Furkan; Vural, BülentIn this work, for electric vehicles (EVs), a novel double input DC-DC power converter, that enables utilization of a battery and ultra-capacitor (UC) in parallel while increasing the overall performance of electric vehicles and recovering regenerative breaking energy, is introduced. Since UCs have higher power density when compared to batteries, by the use of a UC as a power input, DC bus voltage regulation at transients and peak loads is achieved easily, thus the life of the battery and efficiency of the system are increased. The average value model of the proposed converter is created in MA TLAB (R), Simulink (R) and SimPowerSystems (R) environment, then its dynamic performance is tested under the load determined from the ECE-15 drive cycle.Öğe Analysis of Reduced Order Model Based on Doubly-Fed Induction Generators during Different Fault Times(Ieee, 2013) Döşoğlu, Mehmet Kenan; Arsoy, Aysen BasaIn this study, three phase fault analysis of wind turbines consist of Doubly-Fed Induction Generators (DFIGs) has been examined. The dynamic analysis of DFIG has been conducted by Reduced Order Model (ROM). Three Phase fault has been made in 34.5 kV bus, happended in three bus power systems. The three phase fault time has been choosen as 0.02 second, 0.05 second and 0.1 seconds. 154 kV bus voltage, 34.5 kV bus voltage, DFIG output voltage, DFIG angular speed, DFIG electrical torque and DFIG d-q axes stator and rotor current variations of system in different fault times has been examined. According to the results, it has been seen that three phase fault is especially effective upon 34.5 kV bus voltage and DFIG output voltage in different fault time's analysis.Öğe A SOGI Based Band Stop Filter Approach for a Single-Phase Shunt Active Power Filter(Ieee, 2018) Kale, Murat; Akar, Furkan; Karabacak, MuratControl of shunt active power filter (SAPF) requires a cascaded control structure as inner current closed loop followed by outer voltage control loop. The inner current control loop is responsible for tracking of a reference current while the outer voltage loop regulates DC bus voltage to a fixed value. Dynamic performance of the DC bus voltage regulation suffers from the adverse effects such that harmonic currents produced by SAPFs lead to fluctuations in DC bus voltage at certain harmonic frequencies. This causes SAPF to produce additional harmonic components, since the outer voltage loop deals with only fundamental waves where the fluctuations should not appear. This study proposes a DC bus voltage regulation methodology based on a Second Order Generalized Integrator (SOGI) acting as a band-stop filter with the aim of increasing the voltage regulation performance in the steady state. The proposed filter does not affect the transient response thanks to that it only suppresses the harmonic-induced fluctuations in DC bus voltage. Through a simulation study, the proposed methodology is validated, and the results prove the performance and feasibility of the proposed filter.Öğe A Novel FACTS Based on Modulated Power Filter Compensator for Wind-Grid Energy Systems(Ieee, 2014) Duman, Serhat; Altaş, İsmail H.; Yörükeren, Nuran; Sharaf, Adel M.This paper represents a novel FACTS based on modulated power filter compensator (MPFC) for voltage stabilization in renewable wind energy with AC grid connected. Self-excited squirrel-cage induction generator (SEIG) is driven by a wind turbine for renewable a wind energy system. In order to improve voltage stabilization and energy utilization, the proposed FACTS technique is driven by a tri-loop dynamic error driven proportional-integral-derivate (PID) controller. To demonstrate the effectiveness of the proposed FACTS technique, a simulation model is developed for different operation conditions in MATLAB/SIMULINK software environment. Simulation results demonstrate that designed FACTS power filter compensator can be used to provide voltage regulation and efficient energy utilization.Öğe A High Voltage Gain Multi-Input Converter(Ieee, 2018) Akar, Furkan; Kale, MuratThis paper proposes a non-isolated unidirectional high step-up multi-input converter based on switched capacitor cells. The proposed structure specifically useful for hybrid power systems when energy sources with low output voltages, e.g., a photovoltaic system or a fuel cell, need to be connected to a dc bus with high voltage. Moreover, it is possible to store redundant energy into energy storage systems connected to the input of the converter, which is important for renewable energy systems.Öğe A High-Efficiency Bidirectional Non-Isolated Multi-Input Converter(Ieee, 2016) Akar, FurkanA high-efficiency bidirectional non-isolated converter with multiple input sources is presented in this work. In the proposed converter, the energy from/to the input sources is transferred via the coupled inductors connecting to a switch pair. This topology does not only allow active power sharing, but also results in reduced component count. It also achieves zero-voltage-switching without any extra switching losses hence improving the cost-effectiveness, power density and efficiency.Öğe A Comperative Study on Novel Machine Learning Algorithms for Estimation of Energy Performance of Residential Buildings(Ieee, 2015) Sönmez, Yusuf; Güvenç, Uğur; Kahraman, H. Tolga; Yılmaz, CemalThis study aims to improve the energy performance of residential buildings. heating load (HL) and cooling load (CL) are considered as a measure of heating ventilation and air conditioning (HVAC) system in this process. In order to achive an effective estimation, hybrid machine learning algorithms including, artificial bee colony-based k-nearest neighbor (abc-knn), genetic algorithm-based knn (ga-knn), adaptive artificial neural network with genetic algorithm (ga-ann) and adaptive ann with artificial bee colony (abc-ann) are used. Results are compared classical knn and ann methods. Thence, relations between input and target parameters are defined and performance of well-known classical knn and ann is improved substantialy.Öğe A Bidirectional Multi-Phase Multi-Input DC-DC Converter(Ieee, 2017) Akar, FurkanIn this work, a bidirectional non-isolated multiphase multi-input dc-dc converter is proposed. This converter can easily construct hybrid power systems by means of utilizing different power sources and energy storage elements with different characteristics and voltage levels. The proposed converter can work in both buck and boost modes in both directions. Compared to the single phase version, the multi-phase structure helps to decrease the current ripples, thus the sizes of inductors, filter requirements, and semiconductor losses are essentially reduced. In this work, an analysis for the proposed converter concerned its operation modes is presented and details of a simulation study are given to test it for a hybrid energy system.Öğe Optimal power flow incorporating FACTS devices using gravitational search algorithm(2012) Sönmez, Yusuf; Güvenç, Uğur; Duman, Serhat; Yörükeren, NuranThis paper aims to solve the optimal power problem (OPF) incorporating flexible AC transmission systems (FACTS) devices using Gravitational Search Algorithm (GSA) that minimizes the fuel cost function in the problem. In the optimization problem, Thyristor controlled series compensation (TCSC) and thyristor controlled phase shifter (TCPS) FACTS devices are considered to find their optimum location in transmission lines. In order to evaluate the effectiveness of proposed algorithm, it has been tested on modified IEEE 30 bus system and compared with particle swarm optimization (PSO) and hybrid tabu search and simulated annealing (TS/SA) approach which are used in solving the same problem and reported before in the literature. Results show that GSA produces better results than others and has fast computing time for solving OPF problem with FACTS. © 2012 IEEE.Öğe Investigation of various voltage sag analyses in wind farm through SVC(2011) Döşoğlu, Mehmet Kenan; Arsoy, Ayşen BasaIn this study, the systems connect wind farm various voltage sag wind Farm DC link voltage, system buses voltage examined. For study of various transient stability 7.2 MVAr Static Var Compensator (SVC) is used. In the wind farm examined, 6 MW Double Feed Induction Generator (DFIG) is used. Also it examined 3 phase fault, induction motor, both 3 phase fault and induction motor together in wind farm. The results achieved have proved that SVC yield good results when used in terms of transient stability of the system., SVC was found to be effective and successful for eliminating instability in a very short period of time. © 2011 Chamber of Turkish Electric.Öğe Investigation of transient stability of multi machine power systems with multiple UPFC(2011) Döşoğlu, Mehmet Kenan; Arsoy, Ayşen BasaThis study examines the impact of multiple UPFC on transient stability of a power system. A real based multi machine-65 bus system is modeled and analyzed with Unified Power Flow Controller (UPFC). The placement of the compensators is determined based on the transmission lines with highest voltage drop in the system. Transient stability effects are analyzed for three system cases, one without compensators, one with one compensator at a time and the last one with multiple compensators. Angle, angular speed of rotors and voltage of each bus is observed. The simulation results showed that the system with multiple compensators can damp oscillations more effectively, which makes the system in a more reliable operation. © 2011 Chamber of Turkish Electric.Öğe Developing an CNC lathe augmented reality application for industrial maintanance training(Institute of Electrical and Electronics Engineers Inc., 2018) Güler, Osman; Yücedağ, İbrahimIn this study, developing an augmented reality training application for CNC (computer numerical control) lathe looms for industrial maintenance and repair training was described. The content has been developed for the CNC LATHE TEARS module, which is trained in the field of Machine Technologies to be operated on mobile like smart phone, tablet, etc. devices. First a training scenario was prepared for the development of the application. Then three dimensional model of a CNC lathe was modelled. Models designed to develop the augmented reality application have been transferred to the Unity3D game engine software, and using the Vuforia plug-in, a marker-based augmented reality application has been developed to work on android operating system based mobile devices like smartphone, tablet, etc. It is considered that using the developed application in the training of the students of the Machine Technologies Area in the institutions providing vocational and technical education in the official and private institutions affiliated to the Ministry of National Education, motivation of the students and the success rates of the courses will increase. At the same time, the developed application will provide facilitate the training of the users, increase the quality in production and faster maintenance and installation. © 2018 IEEE.Öğe Determination of voltage stability critical loading values using simulated annealing(2009) Tosun, Salih; Öztürk, Ali; Yalçın, Mehmet AliIn this study, critical bus values in a power system are determined by using Simulated Annealing (SA) algorithm. As an example, a power system which contains the slack, generator and load buses is analyzed. Firstly, load value of the selected load bus is augmented step-by-step and load flow analysis is done for each case. This process is continued till there is no solution and in this way the critical bus values that are limit values of voltage stability are obtained. Secondly, by using SA algorithm, critical values are directly determined without augmenting the load of the selected load bus. The results show that the critical values can be easily determined using SA.Öğe A SOGI Based Band Stop Filter Approach for a Single-Phase Shunt Active Power Filter(Institute of Electrical and Electronics Engineers Inc., 2018) Kale, Murat; Akar, Furkan; Karabacak, MuratControl of shunt active power filter (SAPF) requires a cascaded control structure as inner current closed loop followed by outer voltage control loop. The inner current control loop is responsible for tracking of a reference current while the outer voltage loop regulates DC bus voltage to a fixed value. Dynamic performance of the DC bus voltage regulation suffers from the adverse effects such that harmonic currents produced by SAPFs lead to fluctuations in DC bus voltage at certain harmonic frequencies. This causes SAPF to produce additional harmonic components, since the outer voltage loop deals with only fundamental waves where the fluctuations should not appear. This study proposes a DC bus voltage regulation methodology based on a Second Order Generalized Integrator (SOGI) acting as a band-stop filter with the aim of increasing the voltage regulation performance in the steady state. The proposed filter does not affect the transient response thanks to that it only suppresses the harmonic-induced fluctuations in DC bus voltage. Through a simulation study, the proposed methodology is validated, and the results prove the performance and feasibility of the proposed filter. © 2018 IEEE.
