Browsing by Author "Sular, Adem"

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Analysis of Passive Filters for Pv Inverters Under Variable Irradiances
(Ieee, 2019) Karaca, Muhammet; Mamizadeh, Ali; Genc, Naci; Sular, Adem
In this study, passive filters used for photovoltaic (PV) inverters producing different values of power under variable irradiation were analyzed. The use of passive filters is essential to obtain a sinusoidal output voltage with a low harmonic content at the output of PV inverters. For this reason, L-type, L-C and L-C-L type passive filters were designed for PV inverters operating with Maximum Power Point Tracking (MPPT) and Total Harmonic Distortion (THD) analyzes were performed under the same conditions. In addition, the behavior of these filters in PV inverters operating at different irradiations and therefore at different power ratings was observed and compared. In the study, Perturb and Observation (P&O) MPPT technique is used for PV inverter and classical PI controller is used for output voltage control. After the related design studies, the whole circuit with a rated power of 1kW was simulated in the Matlab/Simulink program and the results were compared.
Application of a New Power-Based Control Method for Induction Cooking Systems
(2020) Sular, Adem; Mamızadeh, Alı; Genç, Naci
Endüksiyon ısıtma sistemlerinde kullanılan rezonans evirgeçlerde maksimum güç aktarımı, anahtarlama frekansı rezonans frekansına eşit olduğu zaman gerçekleşir. Endüksiyon ocaklarının tencere türüne ve konumuna göre ortaya çıkan empedansın sürekli değişmesi ve buna bağlı olarak güç aktarım problemi ciddi bir sorun oluşturmaktadır. Bu çalışmada endüksiyon ısıtma sistemlerinde maksimum güç iletmek amacıyla Frekans İzlemeyle Maksimum Güç Transfer (MPTFT) algoritması geliştirilmiş, değişen empedans koşullarında rezonans frekansına çok yakın bir frekansta anahtarlama yapılması garantilenmiştir. Kontrol algoritmalarına tam uyumluluğundan dolayı, tez çalışmasında tam köprü seri rezonans evirgeç topolojisi tercih edilmiştir. Çıkış güç kontrolünün yapılması amacıyla evirgeç girişinde DA/DA Düşüren (Buck) dönüştürücü devresi tercih edilmiş, anahtarlama elemanının doluluk oranının kontrolünde ise Oransal-Integral (PI) kontrolcü kullanılmış ve böylece DA-Bara gerilim kontrolü yapılmıştır. Tasarlanan sistemin benzetim analizleri; Matlab/Simulink ve ANSYS/Maxwell 3D SEA ortamında modellenerek benzetimi gerçekleştirilmiştir. Deneysel uygulamada hızlı işlem yapabilme yeteneğinden dolayı FPGA kontrol kartı kullanılmış ve 1 kW' lık bir sistem tasarlanmış olup benzetim sonuçları ve iki farklı tencere için uygulama sonuçları karşılaştırılmıştır. Yapılan karşılaştırmalar sonucunda deneysel uygulama sonuçlarının Matlab/Simulink ve ANSYS/Maxwell 3D benzetim sonuçlarıyla uyumlu olduğu gözlemlenmiştir. Anahtar kelimeler: Endüksiyon ısıtma ve pişirme, Maksimum güç aktarım yöntemi, Frekans izlemeyle maksimum güç transfer (MPTFT) algoritması, FPGA, ANSYS/Maxwell 3D
Modified Sliding-Mode Controller for the Line-Commutated Converters of Back-To HVDC Systems
(Springer Heidelberg, 2025) Sular, Adem; Meral, Mehmet Emin
Line-commutated converter (LCC) high-voltage direct current (HVDC) systems are currently the most attractive valve converter topology for large-scale HVDC networks due to their high efficiency, low initial installation cost, low power loss, high system stability, and high reliability. This study presents a detailed study of LCC back-to-back HVDC converter stations, identifies the major components of such systems for parameter calculations and supports them with mathematical operations, explains the control methods of the rectifier and inverter units, and proposes a new controller structure. To elucidate its advantages, the proposed controller structure for LCC-HVDC converter stations is compared with other controller structures, namely, the classical proportional-integral (PI) controller and the anti-windup PI controller. The simulation results are obtained from the PSCAD/EMTDC software package. The comparison of the system results, such as settling times and maximum and minimum values for the three controllers, indicates that the proposed modified sliding-mode-based controller (MSMBC) outperforms the two other controllers in all aspects. Therefore, the proposed MSMBC makes highly important contributions to LCC-HVDC converter systems and is superior to other controllers due to its significant advantages.
Pv Power Based Duty Cycle Control of Quasi-Resonant Inverter for Induction Cooking
(Ieee, 2019) Sular, Adem; Mamizadeh, Ali; Genc, Naci; Karaca, Muhammet
In this study, photovoltaic (PV) power-based duty-cycle control is recommended for induction cooking (IC) topologies. The output power of the PV panels changes due to the change in solar irradiation. Based on this PV output power, variable duty-cycle control is recommended for single-switch quasi resonant inverter which is often used for IC applications. In the study, the output power is controlled by using the PV power value produced by MPPT to control the duty-cycle rate of the switch of the resonant inverter according to the variable input power, depending on the variable solar intensity and keeping the temperature and frequency constant. Thus, a quasi-resonant inverter is proposed which adjusts its own power increase or decrease according to the power change in the PV panel. This results in the batteries to be used in the system are allowed to have a longer life and constitute a significant financial gain. PV-powered single-switch quasi resonant inverter circuit with a rated power of 2kW was modeled in Matlab/Simulink environment and the results were presented.