Elektrik Elektronik Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/411
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Article Citation - Scopus: 6Design of Frameless Gimbal Motor for Uav Applications(International Organization on 'Technical and Physical Problems of Engineering', 2022) Arslan, S.; İskender, İres; Iskender, I.; Arslan, Serdar; Elektrik-Elektronik Mühendisliği; Bilgisayar MühendisliğiRecently, application areas of the Unmanned Aerial Vehicle (UAV) systems have started to expand very rapidly due to the fact that offering more effective, economical, reliable and safe solutions compared to manned air platforms, satellites and/or various ground platforms. However, desire to develop higher performance, resourceful, lighter, small and low powered payload make the gimbal platforms mandatory part of the UAVs in a short time and their role is getting increased day by day. In parallel with the increasing demand for precise stabilization, robustness, lightness and agility in gimbal systems, it has become an important trend to use more-electric (ME) customed systems instead of traditional market products. The electric motors that control the speed and position of the gimbal system are simply referred to as gimbal motors. Related design study focuses on designing direct-drive in-runner frameless gimbal motor with the following features; 8.5 VAC line voltages, 24-slot/28-pole combination, 60 rpm, 80 mN.m. Permanent magnet synchronous motor topology is determined to offer higher torque density, higher precision and fast response required for gimbal platforms. The selecting criteria of dimensions, performance parameters, materials, machine type with rotor structures and motor duty cycle are also explained. The gimbal motor is performed analytically in Ansys RMxprt with parametric assignments, statistically and sensitively tuned in Maxwell 2D and optimized in Maxwell 3D by finite element method (FEM) optimetric convergence approach with magnetostatic and transient solutions to get the final machine shape. This study is currently part of the gimbal system to be produced for medium sized surveillance UAV. Since the gimbal motor has been prototyped, all dimensions given are valid. © 2022, International Organization on 'Technical and Physical Problems of Engineering'. All rights reserved.Article Citation - Scopus: 1High Voltage Dc Systems and the Related Commisioning(International Organization on 'Technical and Physical Problems of Engineering', 2020) Haliloglu, A.B.; İskender, İres; Iskender, I.; Elektrik-Elektronik MühendisliğiThe number of High Voltage Direct Current (HVDC) projects worldwide has increased considerably due to the growing interest in this mature technology. Rapid development in semiconductor technology have led to the development of converter technology and thus new application areas have emerged. In this study, historical development of HVDC systems, differences among them considering installation types and application areas are explained. Circuit models of HVDC systems, working principle and general usage purposes are also explained. The differences between conventional Current Source Converters (CSC) and Voltage Source Converters (VSC), which are expressed as relatively new technology, are discussed. Also, within the scope of a project, a HVDC prototype system developed by local engineers from mechanical design to control and protection software has been described. In addition, the tests to be performed before commissioning of HVDC and similar systems are explained. Descriptions of the tests, methods to perform the tests and some issues that should be considered while performing the tests are given. © 2020, International Organization on 'Technical and Physical Problems of Engineering'. All rights reserved.Article Citation - Scopus: 5Three-Phase Buck Type Pfc Rectifier for Electrical Vehicle Battery Charger(International Organization on 'Technical and Physical Problems of Engineering', 2019) Demirkutlu, E.; İskender, İres; Iskender, I.; Elektrik-Elektronik MühendisliğiThree-phase AC/DC buck-type power factor correction (PFC) rectifier is presented in this paper. State of the art three-phase AC/DC rectifiers and improvements of the rectifier topologies are researched in this study. The SWISS Rectifier is implemented for Electrical Vehicle (EV) battery charger with 220 VLN-rmsS / 50 Hz three-phase input. The SWISS Rectifier for EV charger application is implemented by means of simulations. Depending upon the battery pack needs, 48 VDC output voltage is examined under both steady-state and dynamic load change conditions. © 2019, International Organization on 'Technical and Physical Problems of Engineering'. All rights reserved.Article Citation - Scopus: 4Comparing Control Performances of Mrac and Pid Applied on a Brushless Dc Motor(International Organization on 'Technical and Physical Problems of Engineering', 2020) Ciba, S.; İskender, İres; Iskender, I.; Ariani, H.A.; Elektrik-Elektronik MühendisliğiBrushless DC motors are powered by a DC electric source and are used widely used in appliance, automotive, aerospace, medical and industrial equipment due to their compact size and light weight. Parallel to improvements in semiconductor industries the operating frequency of semiconductor switches and microcontrollers are getting improve and this provides conditions to use different algorithms in motor control. In this study the reference model adaptive control of a DC brushless motor will be studied. Brushless DC motors have some advantages such as long working life, high efficiency, and low maintenance requirements; however their control is a bit complicated. For this reason, there have been published many studies in relative with speed control of brushless DC motors. Classical or modern control methods can be used for this purpose. In this study, BLDC motor is controlled with firstly classical PID controller and secondly model reference adaptive control (MRAC) based on MIT law method and the results are compared. © 2020, International Organization on 'Technical and Physical Problems of Engineering'. All rights reserved.Article Citation - Scopus: 10Sensorless Speed Control of a Bldc Motor Using Improved Sliding Mode Observer Technique(International Organization on 'Technical and Physical Problems of Engineering', 2019) Topal, M.; İskender, İres; Iskender, I.; Genc, N.; Elektrik-Elektronik MühendisliğiThis paper proposes controlling the velocity of BLDC motor using sliding mode observer technique based on the estimation of back electromotive force (back EMF). There are many different sensorless control methods for BLDC motor, but in this paper one of them is examined in detail, comparing with the zero crossing points detection of back EMF and hall sensor control. The proposed method estimates the velocity and rotor position by measuring terminal voltages and currents. According to the rotor position, two inverter switches are energized to commutate the phases of BLDC motor. As comparing desired and real line currents, the commutation signals are acquired with hysteresis band. The simulation model of the suggested method is performed by using MATLAB Simulink environment and results have been simulated to interrogate the performance of the BLDC motor under a load change condition also with reference speed. © 2019, International Organization on 'Technical and Physical Problems of Engineering'. All rights reserved.Article Citation - Scopus: 2Pi Control of a Novel Power Converter by Using Heuristic Optimization(International Organization on 'Technical and Physical Problems of Engineering', 2021) Tulay, G.; İskender, İres; Karakaya, M.; Iskender, I.; Elektrik-Elektronik MühendisliğiIn this study, obtaining the PI control coefficients of a power converter using the heuristic optimization method was investigated. A new converter has been designed to increase the lifetime of the energy storage unit of a satellite power subsystem. It is also possible to increase the active duty life of the satellite by using the aforementioned converter according to the increased battery life. © 2021, International Organization on 'Technical and Physical Problems of Engineering'. All rights reserved.Article Citation - Scopus: 11Performance Analysis of a Distribution Transformer Using Ansys Maxwell(International Organization on 'Technical and Physical Problems of Engineering', 2020) Ariani, H.A.; İskender, İres; Iskender, I.; Karakaya, M.; Elektrik-Elektronik MühendisliğiThe purpose of this study is to verify the theoretical calculations of a three-phase transformer by analyzing its magnetic field behaviors and losses under no-load and full-load working conditions using an advanced simulation program that runs based on finite elements method (FEM). This paper presents detailed explanations on defining the parameters and obtaining the results, and also the calculation method for determining the magnitude of the magnetic field and the core and ohmic losses of the transformer. The reliability of the analysis is confirmed by theoretical calculation results. © 2020, International Organization on 'Technical and Physical Problems of Engineering'. All rights reserved.Article Citation - Scopus: 9Design and Performance Analysis of a Three Winding Transformer Used in Solar System(International Organization on 'Technical and Physical Problems of Engineering', 2021) Jahi, A.; İskender, İres; Iskender, I.; Elektrik-Elektronik MühendisliğiDue to the increasing of the fossil fuels prices in the past years and lack of these sources, all scientists encouraged to looking for the alternative energy sources. One of these energy sources is the renewable solar resources. Power transfer from solar systems to grid is achieved using step up transformers. This type of transformer is energized from a converter/inverter with or without variable frequency. The losses of such transformer are higher than those used in sinusoidal voltage power systems. This is due to harmonics content in the transformer input voltage and current. In this study the design and production of a PV transformer have been done according to the IEEE C57.159 guide and the loss analyses of transformer have been done using ANSYS MAXWELL considering the procedures proposed in standards of IEC 61378-1, IEEE C57.110 and the method proposed by Dowell. Finally, the thermal modeling and behavior of the transformer was investigated using the thermal model given in [25] to determine the hot spot and life time of the transformer using MATLAB program. © 2021, International Organization on 'Technical and Physical Problems of Engineering'. All rights reserved.Article Citation - Scopus: 4Cost Optimization of Oil Type Distribution Transformer Using Multi-Objective Genetic Algorithm(Erol Kurt, 2024) Iskender, I.; Yükselen, E.; Telli, S.The demand for electrical energy is increasing day by day with the development of technology in the world. Distributing electric energy to all regions that need energy is a principal issue, and this necessitates the use of transformers to convert the voltage to the desired level. Accordingly, the use of transformers, one of the electrical devices converting AC voltage level at a defined frequency has grown significantly. In this study, design parameters of a 25 kVA, 33/0.4 kV, Yzn11, oil-type distribution transformer are optimized using the Multi-Objective Genetic Algorithm (MOGA) technique by decreasing the weight of the significant materials and manufacturing cost. Electromagnetic analysis of the transformer is performed with ANSYS Maxwell based on the design results obtained from the optimization study for validation of the method. The experimental design parameters are also compared with the optimization results. It is observed that optimum results are achieved by using the proposed approach. © 2024 Published by peer-reviewed open access scientific journal, JES at DergiPark (https://dergipark.org.tr/jes)Conference Object Citation - Scopus: 2Optimal Design of an In-Runner Direct-Drive Synchronous Permanent Magnet Starter/Generator for Uavs(Institute of Electrical and Electronics Engineers Inc., 2022) Iskender, I.; Navruz, T.S.; Arslan, S.The aim of improving efficiency, safety, and reliability as part of more-electric-aircraft initiatives is mediating the rapid development of aerospace systems. In addition, the increasing need for leadership in the sociomilitary-economic area brings the focus of studies on unmanned aerial vehicles in aviation. However, developments in power electronics and control algorithms, permanent magnets, high-speed transmission elements, and iron core material technologies reveal the need for using Starter/Generator structures in hybrid propulsion systems. This paper explores the optimum design of an In-runner Synchronous Permanent Magnet Starter/Generator with specifications of 1 kW-4500 rpm for motor mode and 1.25 kW-5500 rpm for generator mode, especially for small UAVs equipped with a piston engine. Thus, charging the battery packs and the required thrust can be provided with higher efficiency. The preliminary dimensions are obtained analytically. The design issues of materials and topologies are discussed. The novel model is optimised in Ansys Maxwell 2D based on finite element analyses. Dynamic and static simulations are performed with the optimetric sensitivity method, and the efficiency study is carried out in Maxwell 3D. The data obtained as a result of analytical and numerical calculations are verified. © 2022 IEEE.