Selami balcı - Academia.edu (original) (raw)

Papers by Selami balcı

DergiPark (Istanbul University), Dec 1, 2015

Elektrik şebekesinden beslenen ve girişlerinde doğrultucu bulunan motor sürücüleri, kesintisiz gü... more Elektrik şebekesinden beslenen ve girişlerinde doğrultucu bulunan motor sürücüleri, kesintisiz güç kaynakları, AA gerilim ayarlayıcıları gibi elektronik cihazlar yaygın olarak kullanılmaktadır. Yapıları gereği şebekeden doğrusal olmayan akım çeken bu cihazlar, besleme hattı boyunca doğrusal olmayan gerilim düşümlerine sebep olurlar. Bu durumda, önlem alınmadığı takdirde aynı hattan beslenen diğer alıcılar için de güç kalitesi problemleri doğar. Şebeke frekanslı dönüştürücülerin girişinde uygun şekilde tasarlanmış silisli sac nüveli reaktörlerin kullanılması ile çekilen harmonik akımların seviyesi belli oranlara düşürülebilmektedir. Nüve malzemesinin seçimi ve reaktörün boyutlandırılması, akımın harmonik seviyesinin düşürülme kabiliyeti ile reaktörde oluşacak kayıpların belirleyicisi olmaktadır. Bu çalışmada, belirli bir hat akım değeri için nüveleri birbirinden farklı üç reaktör tasarlanmıştır. Tasarlanan reaktörlerin yük seviyesine bağlı endüktans değerlerindeki değişimleri görmek üzere, sonlu elemanlar metodu ile parametrik analizleri yapılmıştır. Analizlerin sonucunda reaktörlerin endüktans kararlılığı, kayıpları, standartlara uygunluğu gibi veriler karşılaştırmalı olarak sunulmuştur. Manyetik devre Ansys-Maxwell ile modellenmiştir. Reaktörün gerçekçi davranışlarını görmek için, manyetik devresinin Simplorer ile eşzamanlı benzetimi yapılmıştır.

ABSTRACT Interleaved DC-DC buck converters are used in medium to high power applications with the... more ABSTRACT Interleaved DC-DC buck converters are used in medium to high power applications with their advantages such as low electromagnetic interference and output voltage ripples. Although, discrete core inductors can be used, coupled inductors which use the same magnetic core can be used to obtain optimum design such as volume, cost and efficiency in interleaved converters. Also, in coupled inductor applications, duty ratio, saturation effect and interactions of the windings should be analyzed carefully. In this study, selection of core structure with different types of coupled inductors is investigated for whole operation range. Simulations are performed with co-simulations of Ansoft-Maxwel 3D and Simplorer software. Inductors that are designed in Maxwell by using Kool Mu E cores are used with buck converter, which was modeled in Simplorer. Results obtained from simulation studies are reported and compared with each other.

International Journal of Hydrogen Energy, Jul 1, 2017

In this study, an isolated three-level DC-DC converter is proposed for high power and high conver... more In this study, an isolated three-level DC-DC converter is proposed for high power and high conversion ratio applications such as fuel cells. The proposed system consists of a single phase three-level inverter, a medium frequency transformer and a diode rectifier unit. In the proposed system, a DC supply voltage is converted to a medium frequency AC voltage via a three-level inverter instead of the conventional two-level inverter. Since the threelevel inverter generates an AC waveform with multiple steps, lower voltage harmonics and lower EMI levels than conventional two-level inverter are achieved. Thus, the threelevel inverter provides higher efficiency value. The medium frequency transformer enables high voltage conversion ratio and provides galvanic isolation as well. The output voltage of the medium frequency transformer is converted to the DC voltage and thus the DC-DC conversion is achieved. According to simulation and experimental results, it is seen that the proposed DC-DC converter structure provides higher power density and higher efficiency values than conventional system.

International Journal of Applied Mathematics, Electronics and Computers, Dec 31, 2022

In this study, the inductor current ripple and output voltage ripple of a two-phase DC-DC boost c... more In this study, the inductor current ripple and output voltage ripple of a two-phase DC-DC boost converter, circuit performance is investigated according to the direct/inverse coupling effect of the coupled inductors. The coupled inductors are modeled with both power electronics circuit and electromagnetic modeling and by using finite element analysis software (FEA). However, the high frequency inductor designs generally use air-gapped composite ceramic ferrite cores and are designed with powder core (Kool Mu) core structures that eliminate air gap requirements. Thus, the fringe flux, which occurs in the air gaps in ferrite cores and reduces the useful flux, and the bad effects such as overheating and electromagnetic noises (EMI/EMC) in the air gaps in high frequency switching are also reduced. Especially in interleaved power converter designs, the performances of coupled inductors affect the output parameters of the power electronics circuit. Considering energy efficiency and more compact circuit topologies, the modeling and simulation approach of high-frequency inductors using finite element analysis software, which is emphasized in this study, popularly and scientifically guides power electronics circuit designers.

2022 11th International Conference on Renewable Energy Research and Application (ICRERA), Sep 18, 2022

This paper presents a reliable methodology based on imperialist competitive algorithm (ICA) for e... more This paper presents a reliable methodology based on imperialist competitive algorithm (ICA) for estimating the optimal parameters of photovoltaic (PV) generating unit. The PV system is simulated by single diode model and double diode model. The proposed constrained objective function is derived from the voltage-power curve of the PV system which has unique maximum power point (MPP). The analysis is performed on different types of PV systems; mono-crystalline, poly-crystalline and amorphous modules. The validation of ICA is investigated for PV cell/module operated under different irradiances and temperatures; the obtained results are compared with experimental data and other reported meta-heuristic optimization algorithms. The results confirm the validity and reliability of ICA in extracting the optimal parameters of the PV generating unit.

In this paper, 4-phase interleaved buck converter is simulated and implemented by using 16 bit ds... more In this paper, 4-phase interleaved buck converter is simulated and implemented by using 16 bit dsPIC30F2020 microcontroller. Proposed interleaved buck converter can operate as a single converter or interleaved converter mode. It shares the load current, and changes its switching frequency according to operation mode to achieve same ripple effect in interleaved converter mode. Before implementation stage firstly, the saturation effect of inductors and performance of converter have been tested and the system is simulated with co-simulation carried out with MATLAB/Simulink and FEM-based software. The data obtained from FEM-based software and Simulink is compatible with each other. Finally whole system is implemented and the advantages of the proposed converter structure have been presented based on comparison of simulated and experimental results with a traditional buck converter. It is seen that output current ripple, EMI level and voltage stress on components are reduced with proposed interleaved converter.

Journal of Electronic Materials, May 5, 2016

In this study, design and thermal analysis of a medium-frequency transformer with ferrite N87 cor... more In this study, design and thermal analysis of a medium-frequency transformer with ferrite N87 core have been carried out using finite-element analysis software. A thermal model of the medium-frequency transformer is generated and analyzed with different cooling methods. In addition, it is proposed to attach additional heat sinks at the top and bottom of the transformer core. Effects of these additional heat sinks on cooling performance and sizing of the transformer are investigated. Furthermore, the cooling capacity of the proposed material is investigated, depending on the air flow velocity for the forced-air cooling method. Thus, more realistic behavior of the ferrite N87 material is obtained for a medium-frequency transformer with 35 kVA rated power and 10 kHz operating frequency. Moreover, electromagnetic and thermal analyses are carried out through linked simulations. The heat distribution in the core including saturation effect is also investigated in detail.

This paper analyzes the dynamio performance of permanent magnet (PM) f%mchronous motors using dam... more This paper analyzes the dynamio performance of permanent magnet (PM) f%mchronous motors using damping and synchronizing torques. A numerical algorithm has been applied to obtain these torque components using a time-domain analysis off nonlinear systems. The effects of all electrical parameters have been examined and the optimum values which give maximum internal damping are defined. It has also beed demonstrated that the choice of the optimum values of these parameters results in well damped oscillations with improved dynamical performance following load changes.

DC-DC converters are commonly used in many fields such as renewable energy sources, electrical ve... more DC-DC converters are commonly used in many fields such as renewable energy sources, electrical vehicles, power supplies, battery chargers and fuel cell applications. These converters are used for purposes such as voltage conditioning, regulation of their outputs, obtaining maximum power and providing isolation. In practice, various criteria such as cost, performance, efficiency and size are considered while converter topology is determined. Filter components (L-C) which are used in DC-DC converter determine the converter size. In this study, an interleaved quadratic boost converter is designed for fuel cell applications and different inductor designs are investigated for the proposed quadratic boost converter. Four different inductor models are designed and simulation studies of the interleaved quadratic boost converter with these inductor models are carried out. Effects of the designed inductors on converter output waveform quality, total weight and volume, and converter efficiency are investigated and obtained results are compared. It is seen from obtained results that, the coupled inductor improves performance and efficiency of the interleaved quadratic boost converter.

Existing classical power grid systems are very sensitive against the integration of renewable and... more Existing classical power grid systems are very sensitive against the integration of renewable and distributed energy sources due to voltage and frequency fluctuations that cause several problems like power outrage and blackouts. On the other hand, increasing the power capacity of the existing grid system as well connection of the renewable energy sources to the grid are unavoidable. So that, a smooth connection of renewable and distributed power system to the grid is required and many researchers have done several researches on this hot topic. Therefore, intelligent techniques to connect the renewable energy sources to the grid have been addressed in this study and recent researches in this field have been reviewed and some comments have been done for the researchers, young engineers, students, transmission system operators, distribution system operators as well as policy makers and end users.

Europan journal of science and technology, Mar 25, 2023

Öz Günümüzde doğal ya da insan kaynaklı afetler binlerce insanın yaşamını yitirmesine veya hayat ... more Öz Günümüzde doğal ya da insan kaynaklı afetler binlerce insanın yaşamını yitirmesine veya hayat kalitesinin düşmesine sebep olmuştur. Bu bağlamda insanların can ve mal kayıplarını minimize etmek için arama kurtarma ekipleri her türlü afet ya da vakaya uygun ekipmanını envanterinde bulundurmak zorundadır. Envanterindeki ekipman arama kurtarma ekiplerinin olaya müdahale süresini kısaltabileceği için hayati öneme sahiptir. Kanatları hareketli olarak tasarlanan robot, doğal afetlerde mahsur kalan bireylere olayın türüne göre arama kurtarma ekipleri tarafından ilgili modül takılarak karadan veya havadan temel düzeyde (Powerbank, cep telefonu, özel ilaç ve gıda malzemesi gibi) malzeme yardımında bulunabilecektir. Böylelikle yaralının ya da afetzedenin hayatta kalma süresi artacaktır. Kanatları hareketli otonom robotun benzetim ve tasarımları Solid Works ortamında yapılmış olup gerekli donanım ve entegrasyon işlemleri de detaylıca ele alınmıştır. Prototipi gerçekleştirilen bu çalışmada farklı modüller takılarak robot hem karada hem havada hareket etmesi sağlanmıştır. Bunun yansıra kanatların istenilen açıda hareketi sağlanmış olup karada hareket esnasında manevra kabiliyeti gözlemlenmiştir. Ayrıca, robot karada hareket ederken yük taşıma haznesi kapaklarının kontrolü de sağlanmış ve başarılı sonuçlar elde edilmiştir. Robot İHA olarak kullanıldığında otonom-manuel uçuş esnasında görüntü aktarmada başarılı sonuçlar gözlemlenmiştir.

Electric Power Components and Systems, Nov 8, 2022

Medium-frequency power transformers are used in DC-DC converters topologies such as photovoltaic,... more Medium-frequency power transformers are used in DC-DC converters topologies such as photovoltaic, wind turbines, fuel cells, electric vehicles and uninterruptible power supply systems. In the design of magnetic circuit components such as transformer and inductor, the choice of the core material is of great importance in terms of losses and magnetic induction. For determining the size of the medium-frequency transformer, frequency and magnetic flux density are also two key parameters. In this study, the core volume change with the frequency is mathematically analyzed and modeled by using finite element analysis method. Parametric analysis provides very useful information in order to determine the excitation voltage level, which does not cause the saturation in the core, for the switching frequency. Thus, parameters of the designed transformer equivalent circuit can be optimized. Then, medium-frequency transformer is operated in power electronic circuits and saturation effect and core losses according to the preferred magnetic materials are investigated by performing co-simulation.

Karamanoğlu Mehmetbey Üniversitesi Mühendislik ve Doğa Bilimleri Dergisi

Elektrik enerjisi talebi tüm dünyada giderek artmakta ve sürdürülebilir enerji sağlama açısından ... more Elektrik enerjisi talebi tüm dünyada giderek artmakta ve sürdürülebilir enerji sağlama açısından şebeke altyapıların sürekli olarak geliştirilmesi gerekmektedir. Bu açıdan karmaşık davranışa sahip olan elektrik şebeke sistemlerinde yük tahminleri hem enerjinin etkin kullanımı hem de tedarikçi firmaların enerji şebekesi planlaması ve kamu hizmeti şirketi faaliyetleri için temel endekslerden biridir. Bu çalışmada, endüstriyel bir bölgede faaliyet göstermekte olan tüketicilerin saatlik, günlük, aylık ve yıllık olarak enerji harcamalarına ilişkin olarak geçmiş yıllardaki kullanımları dikkate alınarak gerçek bir veri seti değerleri elde edilmiştir. Daha sonra bu değerler kullanılarak gelecekteki yük profili ve taleplerinin belirlenmesine yönelik yaklaşımlar rapor edilmiştir. Böylece, geçmiş yıllardaki elektrik enerjisi tüketim verilerine dayalı olarak yük profili belirlenmiş olan endüstriyel tüketicilerin gelecekteki enerji taleplerinin ön kestiriminin yapılabilmesinde Karaman Organize S...

International Journal of Applied Mathematics Electronics and Computers

Kastamonu University Journal of Engineering and Sciences

In this study, it is aimed to isolate the output interface of single-phase inverter circuits and ... more In this study, it is aimed to isolate the output interface of single-phase inverter circuits and the grid from each other. For this purpose, three-dimensional isolation transformers are designed with a software using the In order to determine the leakage inductance behavior of the isolation transformer, whose electromagnetic modeling was carried out with Ferrite N87 core material, the geometric distances of the primary-secondary windings and the diameter sizing of the windings were changed in parametric linear steps, and a data set was obtained as a specific parametric scenario for the leakage inductance values. Thus, the estimation process of the electromagnetic modelling of the transformer has been successfully carried out thanks to the training and testing processes of Adaptive Network Based Fuzzy Inference Systems (ANFIS) with the numerical information obtained from the finite element analysis (FEA) parametric data set. After the estimation processes, the percentage error is cal...

Kalıcı tip mıknatıslı senkron motorlar, günümüzde sabit güç ve değişken hız gereksinimi olan bazı... more Kalıcı tip mıknatıslı senkron motorlar, günümüzde sabit güç ve değişken hız gereksinimi olan bazı otomasyon sistemlerinde, beyaz eşyalarda, savunma sanayii uygulamaları gibi birçok alanda kullanılmaktadır. CNC tezgâhları, ahşap tornaları, metal tornaları gibi ağır tork ve yüksek devir gerektiren uygulamalarda ise mil motorlar tercih edilir. Küçük bir hacme sahip olmalarına rağmen mil motorları, bulundukları sistemlerin daha yoğun ve verimli çalışmasını sağlarlar. Son yıllarda popüler konu haline gelen sonlu elemanlar analizi (SEA) yaklaşımı ile elektrik motorlarının performans incelemeleri, elektromanyetik modelleme ve benzetim çalışmaları kolaylıkla yapılabilmektedir. Böylece, farklı yapı ve özelliklerde tasarlanabilen elektrik motorlarının akım, gerilim, güç, tork ve hız karakteristikleri elde edilebilmektedir. Bu çalışmada, SEA yazılımı kullanılarak kalıcı tip mıknatıslı motorların (IPM) ve IPM mil motorların çalışma performanslarının karşılaştırması üzerine bir benzetim örneği verilmiştir. Böylece, mekatronik uygulama alanlarında sıkça kullanılan mil motorların tasarımı üzerine elde edilen performans verileri elde edilmiştir. Elektrik makinelerinin tasarımı konularına ilgi duyan araştırmacılar için örnek bir karşılaştırmalı SEA benzetim çalışması sunulmuştur.

Journal of Energy Systems

The inverters are frequently used in power electronics applications in the industrial area. Resea... more The inverters are frequently used in power electronics applications in the industrial area. Research on multi-level inverter circuit designs in power systems interfaces has intensified in recent years. The design type and quality of the inverter circuit topology is very important for the output voltage to be closer to the sinusoidal waveform. In addition, artificial intelligence techniques for the control algorithms of the power switches of the inverter circuit provide useful information in terms of monitoring the estimated the voltage conditions of the inverter output parameters. In this work, an Adaptive-Network Based Fuzzy Inference Systems (ANFIS) model is proposed to estimate the Total Harmonic Distortion (THD) value of the output current of a three-phase three-level inverter circuit. By changing the switching frequency in the control circuit of the inverter, a data set for the THD values of the inverter current is obtained by Fast Fourier Transform (FFT) analysis in MATLAB. Th...

Özet. Bu çalışmada, park ve bahçelerdeki çimleri biçmek için yüksek verimli, düşük maliyetli, kom... more Özet. Bu çalışmada, park ve bahçelerdeki çimleri biçmek için yüksek verimli, düşük maliyetli, kompakt ve otonom olarak hareket edebilen bir çim biçme makinesi robotu tasarlanmıştır. Geliştirilen robotun kontrolünde Arduino Nano kartı kullanılmıştır ve ön kısmına yerleştirilen ultrasonik mesafe sensör ile engeller algılanarak yön değiştirmesi sağlanmıştır. Ayrıca, enerji ihtiyacı için güneş enerjisinden faydalanılmıştır ve lityum-ion pillerin şarj olabilmesi için üst kısmına güneş paneli monte edilmiştir. Güç sistemindeki OLED monitör sayesinde pillerin durumu, şarj seviyesi gibi bilgiler kullanıcıya aktarılabilmektedir.

2018 IEEE 12th International Conference on Compatibility, Power Electronics and Power Engineering (CPE-POWERENG 2018), 2018

The main factor that has to be considered in the inductor designing is the power losses occurred ... more The main factor that has to be considered in the inductor designing is the power losses occurred in the core and windings, and temperature rise released depend on these power losses. In addition to worsening efficiency, temperature rise due to the power losses reduce lifespan of the isolation materials and cause significant change on electromagnetic behavior of the core. These effects become more important for the high power medium frequency inductors. Therefore, the cooling conditions have to be considered during the designing stage to keep the temperature rise of the inductors at a certain level. In this study, medium frequency inductor of an LCL filter used in the grid interactive inverter output has been designed. The toroidal gapped-core shape has been made up with silicon steel alloy. The core and the winding power losses of the inductor have been determined with finite element analysis (FEA) based co-simulations, and then its thermal behaviors have been investigated with the calculated heat sources for different ambient temperatures.