İskender, İres
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Iskender, Ires
Iskender, I.
Iskender, I.
Job Title
Prof. Dr.
Email Address
ires@cankaya.edu.tr
Main Affiliation
Elektrik-Elektronik Mühendisliği
Status
Current Staff
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Scopus Author ID
Turkish CoHE Profile ID
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WoS Researcher ID
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Sustainable Development Goals
11
SUSTAINABLE CITIES AND COMMUNITIES
0
Research Products
3
GOOD HEALTH AND WELL-BEING
0
Research Products
9
INDUSTRY, INNOVATION AND INFRASTRUCTURE
2
Research Products
6
CLEAN WATER AND SANITATION
0
Research Products
14
LIFE BELOW WATER
0
Research Products
12
RESPONSIBLE CONSUMPTION AND PRODUCTION
0
Research Products
8
DECENT WORK AND ECONOMIC GROWTH
0
Research Products
1
NO POVERTY
0
Research Products
4
QUALITY EDUCATION
0
Research Products
5
GENDER EQUALITY
0
Research Products
10
REDUCED INEQUALITIES
0
Research Products
16
PEACE, JUSTICE AND STRONG INSTITUTIONS
0
Research Products
15
LIFE ON LAND
0
Research Products
7
AFFORDABLE AND CLEAN ENERGY
16
Research Products
13
CLIMATE ACTION
1
Research Products
17
PARTNERSHIPS FOR THE GOALS
1
Research Products
2
ZERO HUNGER
0
Research Products
Documents
80
Citations
693
h-index
16
Documents
59
Citations
446
Scholarly Output
39
Articles
26
Views / Downloads
393/110
Supervised MSc Theses
5
Supervised PhD Theses
0
WoS Citation Count
50
Scopus Citation Count
137
WoS h-index
4
Scopus h-index
7
Patents
0
Projects
0
WoS Citations per Publication
1.28
Scopus Citations per Publication
3.51
Open Access Source
11
Supervised Theses
5
| Journal | Count |
|---|---|
| International Journal on Technical and Physical Problems of Engineering | 9 |
| International Journal of Renewable Energy Research | 4 |
| Engineering Science and Technology, an International Journal | 2 |
| 2nd International Symposium on Multidisciplinary Studies and Innovative Technologies (ISMSIT) -- OCT 19-21, 2018 -- Kizilcahamam, TURKEY | 1 |
| 9th International Conference on Electrical and Electronics Engineering (ICEEE) -- MAR 29-31, 2022 -- Alanya, TURKEY | 1 |
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39 results
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Now showing 1 - 10 of 39
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: 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 Amorf Çekirdekli Transformatörün Çoklu Fizik Yöntemiyle Elektromanyetik - Sıcaklık Analizi(2021) Najafi, Atabak; İskender, İresBu makalede, Amorf nüveli transformatörün sıcaklık analizini detaylı incelemek için, ısı transferi, akışkan akışı ve elektromanyetik analizlerini kapsayan çok disiplinli bir yaklaşım kullanılmıştır. Transformatörün bobini ve çekirdeğindeki güç kayıpları incelenip, sıcaklık ve akışkan akış analizleri elektromanyetik bir model ile birleştirilmiştir. Önerilen yöntem, Amorf çekirdekli gibi özel transformatörlerde, önceki noktasal sıcaklık bilgisine ya da sıcaklık Gradyan değerlerine ihtiyaç duymadan, sıcaklık değişimini detaylı olarak tahmin edebilmektedir. Teorik çalışma sonuçları uluslararası standartlara göre Dyn11, 34.5/0.4-kV, 630-kVA’lik amorf çekirdekli transformatör üzerine uygulanan deneysel çalışma sonuçlarıyla doğrulanmıştır. Teorik ve pratik çalışma sonuçlarının karşılaştırılması, sonuçların büyük bir uyum içinde olduğunu göstermekte olup, kullanılan yöntem genç mühendislere güç transformatörlerin sıcaklık analiz çalışmalarında faydalı bir araç oluşturmaktadır.Article Citation - WoS: 1Citation - Scopus: 3Surge Arrester Allocation for Lightning Protection of Vsc Based Hvdc Prototype(Elsevier - Division Reed Elsevier india Pvt Ltd, 2023) Haliloglu, Ali Burhan; Iskender, Ires; Burhan Haliloglu, AliHigh-voltage direct current (HVDC) systems, based on voltage source converters (VSC), enable asynchronous interconnection of grids with different frequencies and contribute to grid stability by controlling power quickly and precisely. Effective protection of these expensive systems, which must be in continuous operation, increases their lifetime. An overvoltage protection study is needed to ensure the proper protection of HVDC systems that contain multiple devices with varying insulation levels. In this study, lightning protection studies on a prototype VSC-based HVDC (VSC-HVDC) system are explained. In line with this, lightning impulses were modeled and applied to various points in the PSCAD model of the prototype VSC-HVDC, and the response of the system combined with the protection equipment was examined. All stages of protective equipment selection were explained step by step. The suitability of the selected protective equipment was verified based on the simulation results. After running dozens of scenarios, the protection coordination was optimized, and the critical points were determined instead of installing surge arresters at each connection point. In this way, a significant cost benefit was obtained for the investment in protective equipment. Finally, the results of the lightning impulse tests performed to verify the insulation of the VSC-HVDC prototype are reported.Conference Object Citation - Scopus: 4Analysis of Short Circuit Electromagnetic Force in a Three Winding Transformer Used in Solar System(Institute of Electrical and Electronics Engineers Inc., 2021) Iskender, I.; Jahi, A.Due 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 renewable solar energy. Power transmission from solar systems to grid is achieved using step up transformers. This type of transformer is energized from two inverter with or without variable frequency. Power transformers are deals with a variety of mechanical, electrical and thermal stresses during normal life time operation. Transient electromagnetic forces cause mechanical stress on transformer parameters where calculation of these forces with traditional methods is extremely complex due to the geometry of the transformer. Accordingly in this study, the electromagnetic forces takes place in the windings of a Photovoltaic (PV) transformer are investigated and for calculation of these forces, the 3D and 2D model of transformer is adapted in the ANSYS Workbench. The analysis of electromagnetic forces during the three line fault on high voltage side of the transformer are performed by the Finite Element Method (FEM) and compared with the analytical results. The numerical modeling technique discussed in this study would be useful in the design stage of PV transformer with regard to evaluate ability of transformer to withstand the short circuit current. © 2021 Chamber of Turkish Electrical Engineers.Article Citation - WoS: 3Citation - Scopus: 3Finite Element Method-Based Optimisation of Magnetic Coupler Design for Safe Operation of Hybrid Uavs(Mdpi, 2023) Iskender, Ires; Navruz, Tugba Selcen; Arslan, SamiThe integration of compact concepts and advances in permanent-magnet technology improve the safety, usability, endurance, and simplicity of unmanned aerial vehicles (UAVs) while also providing long-term operation without maintenance and larger air gap use. These developments have revealed the demand for the use of magnetic couplers to magnetically isolate aircraft engines and starter-generator shafts, allowing contactless torque transmission. This paper explores the design aspects of an active cylindrical-type magnetic coupler based on finite element analyses to achieve an optimum model for hybrid UAVs using a piston engine. The novel model is parameterised in Ansys Maxwell for optimetric solutions, including magnetostatics and transients. The criteria of material selection, coupler types, and topologies are discussed. The Torque-Speed bench is set up for dynamic and static tests. The highest torque density is obtained in the 10-pole configuration with an embrace of 0.98. In addition, the loss of synchronisation caused by the piston engine shaft locking and misalignment in the case of bearing problems is also examined. The magnetic coupler efficiency is above 94% at the maximum speed. The error margin of the numerical simulations is 8% for the Maxwell 2D and 4.5% for 3D. Correction coefficients of 1.2 for the Maxwell 2D and 1.1 for 3D are proposed.Master Thesis Mıl-std-461g Ce102'yi Karşılayacak Dc-dc Dönüştürücüler için Emı Filtre Tasarımı(2025) Ovalı, Tuğba Nur Atabey; İskender, İresElektromanyetik girişim (EMI), elektrikli cihazlar tarafından yayılan ve diğer elektrikli ekipmanların çalışmasını olumsuz yönde etkileyen istenmeyen dalgaları ifade eder. Günümüzde birçok elektronik cihaz, işlevselliğini ve performansını olumsuz yönde etkileyen EMI sorunları yaşamaktadır. Bu sorunu çözmek için çeşitli topolojilere sahip filtreler kullanılır. Özellikle tasarlanan filtrelerin MIL-STD-461G gibi EMC standartlarına uygun olmasına ve filtre tasarımlarının kesme frekansı, empedans uyumu, parazit etkileri gibi parametrelerle uyumlu olmasına dikkat edilmektedir. Elektromanyetik uyumluluk (EMC), cihazların yaydığı elektromanyetik enerji nedeniyle diğer cihazların çalışmasına müdahale etmeden çalışabilmesini ve harici elektromanyetik girişimlerden etkilenmeden işlevlerini yerine getirmeye devam edebilmesini sağlar. Günümüz teknolojisinde EMC uyumlu dönüştürücüler, savunma ve havacılık sanayisinden, uydu ve uzay sistemlerine, tıbbi cihazlardan endüstriyel otomasyon ve kontrol sistemlerine kadar pek çok alanda kullanılmaktadır. Bu cihazlar elektromanyetik girişim kontrolü sayesinde performans kriterlerini karşılar. Bu çalışma, MIL-STD-461G CE102 standartlarına uygun DC-DC dönüştürücüler için EMI filtrelerinin tasarımına odaklanmaktadır. Başlangıçta askeri sınıf dönüştürücünün gürültü profili ölçümleri elde edildi. Gürültü profilleri çıkarıldıktan sonra kullanılacak kesme frekansı ve ekleme kaybı gibi parametreler filtre tasarımında hesaplanmıştır. Son olarak teorik hesaplamalar LTspice programı kullanılarak simüle edildi ve filtrenin uygulamalı üretimi yapıldı.Article Citation - WoS: 2Citation - Scopus: 3Analysis and Design of a Special Type Power Transformer Used in Solar Power Plants(Gazi Universitesi, 2022) Yükselen, E.; Iskender, I.Due to growing of greenhouse gas emissions and lack of the fossil sources, governments encouraged all scientists and utilities for looking to the alternative energy sources such as solar renewable energy which can help to reduce carbon dioxide emissions. In this respect, Photovoltaic (PV) power plants have become more important in recent years and renewable energy sources integrated into the power system are increasing day by day. Transformers are the main components of electrical grids and are widely used in renewable power plants to transfer the energy they produce to the grid. Accordingly, transformers are one of the most critical equipment of PV plants, and their safe operation and stability in the electrical network are important. This type of transformer is supplied from solar panels through inverters and needs to be customized to work with each system. In this type of transformer, the losses are higher than those for transformers used in electrical power systems supplied by sinusoidal voltage considering existence of different voltage and current harmonics content produced by the inverter. In this study, a special type of PV transformer was designed in accordance with the target performance criteria, taking into account the effects of harmonics, and keeping the transformer losses and temperature rise at a safe level. In this paper also the simulation results are compared with those of experiments test to verify the design procedures. © 2022. International Journal of Renewable Energy Research.All Rights ReservedConference Object Citation - WoS: 3Citation - Scopus: 6A Novel Transformerless Single-Phase Three-Level Buck-Boost Inverter(Ieee, 2023) Demirkutlu, Eyyup; Iskender, IresThis paper proposes a novel transformerless, single-phase, three-level, buck-boost inverter. The proposed inverter can suppress the leakage current drawn from the input power source and provide a long-lasting solution for applications with a wide range and unregulated input voltage. Unlike similar topologies, in the proposed inverter there is no need to have a mid-point of DC sources or DC bus capacitors at the input side of the inverter. A single-phase, three-level, buck-boost inverter for realizing the power stage with 110-Vrms output AC voltage and a range of 100V-200V input DC voltage is investigated in this study. The proposed topology has been proven through theory, computer simulations, and experimental studies with SiC MOSFETs-based prototype of a 300-VA power supply. Theory, computer simulation, and experimental results are all correlated.Master Thesis Havacılık Uygulamaları için Dijital LLC Şarj Cihazının Simülasyonu ve Uygulaması(2025) Ünsal, Ali Kaan; İskender, İresLLC topolojisi batarya şarj cihazlarında sıklıkla kullanılmaktadır. Bu yüksek verimli topoloji özellikle uçaklarda kullanılan dahili batarya şarj cihazları için uygundur. Bu sayede uçaklarda daha küçük ve daha hafif bir şarj cihazı kullanılır. Dahili şarj cihazı bulunan uçaklar, acil durum bataryalarını sadece uçuş öncesinde değil, uçuş sırasında da şarj edebilmektedir. Bu tezde, donanım-içinde-çevrim test ortamı ile test edilecek DO-178C standardının temel ilkelerine uygun olarak yazılım geliştirilecek, dijital kontrollü bir batarya şarj cihazı tasarlanacak ve simüle edilecek. Tezin organizasyonu şu şekildedir. Bölüm I, LLC şarj cihazı ihtiyacını ve tasarımı için bir yol haritası sunmaktadır. Bölüm II, lityum-iyon bataryalar, rezonant LLC konvertörü, PID ve DO-178C havacılık standardı hakkında genel bilgiler vermektedir. Bölüm III, dijital LLC devresinin tasarımını sunmakta; LLC devresi ve PI kontrol tasarımını ayrıntılı şekilde açıklamakta ve simülasyon sonuçları paylaşmaktadır. Bölüm IV, yazılım gereksinimleri ve tasarımını içermektedir. Bölüm V, donanım-içinde-çevrim test metodolojisini ve geliştirilen LLC devre kaynak kodunun hedef cihaz üzerinde çalıştırılmasıyla elde edilen sonuçları sunmaktadır. Bölüm VI sonuçları ve gelecekte yapılabilecek çalışmalar için önerileri vermektedir.
