Yazar "Karafil, Akif" seçeneğine göre listele

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  • Küçük Resim Yok
    Öğe
    Comparison of regular and irregular 32 pulse density modulation patterns for induction heating
    (Wiley, 2021) Karafil, Akif; Ozbay, Harun; Oncu, Selim
    In this study, an induction heating (IH) application is carried out by transferring the maximum power extracted from photovoltaic (PV) panels to the stainless steel with the designed regular and irregular 32 pulse density modulation (PDM) controlled series resonant inverter. The main objective of this study is to analyse the changes in the system due to regular and irregular PDM patterns. Maximum power point tracker (MPPT) is used to control the output power at different solar irradiation values with varying PDM patterns. Regular and irregular PDM control methods are compared in terms of MPPT efficiency, cost, algorithm complexity, logic control structure and current/voltage stresses of the power switches. Zero current switching (ZCS) conditions are provided by using phase locked loop (PLL) technique at all power points of the PV system. The appropriate switching conditions are tracked continuously at resonant frequency, and therefore soft switching is realised. Perturb and observe (P&O) algorithm is used with the aim of tracking the maximum power in PV panels and high tracking efficiency is obtained with PDM-controlled P&O MPPT algorithm. ATMEL328P-AU microcontroller is used to control the inverter in the system.
  • Küçük Resim Yok
    Öğe
    Design and Analysis of Single-Phase Grid-Tied Inverter With PDM MPPT-Controlled Converter
    (Ieee-Inst Electrical Electronics Engineers Inc, 2020) Karafil, Akif; Ozbay, Harun; Oncu, Selim
    In this article, a novel method is presented for maximum power point tracker (MPPT) system to increase efficiency. For this purpose, maximum power obtained from photovoltaic (PV) panels by pulse density modulation (PDM)-controlled high-frequency series-resonant converter was transferred to grid by a single-phase inverter. The resonant converter and the single-phase inverter circuits used in the system were analyzed, designed, simulated, and implemented. The designed series-resonant converter was operated at resonant frequency for different solar radiation conditions using the PDM control technique, and therefore the maximum power point was tracked. Soft switching was achieved by continuously tracking the resonant frequency. Simulated and experimental results were presented for 600 W prototype by operating the MPPT converter over 100 kHz. The MPPT efficiency was obtained as 99 & x0025; and above. The maximum power tracking of the PV panels was achieved using the perturb and observe (P & O) algorithm with PDM technique. The generated PV power was transferred to the single-phase grid by an LCL-filtered inverter. Proportional integral controller was preferred in the control of single-phase grid-tied inverter.
  • Küçük Resim Yok
    Öğe
    PDM kontrollü rezonans dönüştürücülü MPPT içeren bir fazlı şebeke etkileşimli eviricinin gerçekleştirilmesi
    (Karabük Üniversitesi, 2018) Karafil, Akif; Öncü, Selim
    Bu tez çalışmasında, pals yoğunluk modülasyonu (PDM) kontrollü yüksek frekanslı rezonans dönüştürücü ile fotovoltaik (PV) panellerden elde edilen maksimum güç bir fazlı eviriciyle şebekeye aktarılmaktadır. Sistemde yer alan rezonans dönüştürücü ve bir fazlı evirici devrelerinin analizi, tasarımı, benzetimi ve uygulaması gerçekleştirilmiştir. Tasarlanan rezonans dönüştürücü, PDM kontrol yöntemi ile farklı güneş ışınım koşulları için rezonans frekansında çalıştırılarak maksimum güç noktası takibi (MPPT) yapılmaktadır. Rezonans frekansında uygun anahtarlama koşulları sürekli takip edilip yumuşak anahtarlama sağlanarak anahtarlama kayıpları azaltılmaktadır. PV simülatör kullanılarak 600 W'lık sistemde MPPT dönüştürücüsü 100 kHz üzerinde çalıştırılarak deneysel sonuçlar alınmıştır. İlk olarak, PV sistemin her güç noktasında faz kilitlemeli döngü (PLL) tekniği kullanılarak sıfır akım anahtarlama (ZCS) koşulları sağlanmış olup güç takibinin yapılabilmesi için PDM ile kontrol edilen izoleli tam köprü seri rezonans DA-DA güç dönüştürücünün uygulaması gerçekleştirilmiştir. PV panellerdeki maksimum gücün takip edilebilmesi için değiştir-gözle (P&O) algoritması kullanılmıştır. PV panellerden elde edilen maksimum güç LCL filtreli evirici ile bir fazlı şebekeye aktarılmaktadır. Bir fazlı şebeke etkileşimli eviricinin kontrolünde basit olması sebebiyle endüstriyel uygulamalarda yaygın olarak kullanılan oransal integral (PI) denetleyici tercih edilmiştir. Hem rezonans dönüştürücü hem de bir fazlı şebeke etkileşimli evirici tek bir dijital sinyal işlemcisi (DSP) üzerinden kontrol edilmiştir. Böylelikle maliyet ve sistem karmaşıklığı azaltılır.
  • Küçük Resim Yok
    Öğe
    Power Control of Resonant Converter MPPT by Pulse Density Modulation
    (Ieee, 2017) Karafil, Akif; Ozbay, Harun; Oncu, Selim
    This paper presents the simulation of series resonant converter system with proposed 32 pulse density modulation (PDM) patterns which transfer the electrical energy obtained from PV panels to load with high power density. Maximum power point tracking (MPPT) is achieved by deleting some control pulses. Therefore, zero current switching (ZCS) is achieved at 100 kHz resonant frequency. The average output power changes of series resonant converter are given according to the proposed 32 PDM patterns. Both the MPPT algorithm and the high frequency series resonant converter are controlled by TMS320F28335 DSP. In the 600 W PV system, soft switching condition is achieved by using the proposed 32 PDM technique.
  • Küçük Resim Yok
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    Pulse density modulation controlled converter for PV systems
    (Pergamon-Elsevier Science Ltd, 2017) Oncu, Selim; Karafil, Akif
    This paper presents a pulse density modulation (PDM) controlled resonant converter for photo-voltaic (PV) system. Maximum power point of the PV generation system is tracked by deleting some control pulses of full bridge series resonant converter. Phase of the converter current is controlled by phase locked loop circuit and zero current switching is achieved for different irradiation conditions. Perturb and observe method is used for maximum power point tracker and designed system is experimentally tested by solar array simulator for 600 W PV power with 116 kHz PDM-MPPT controlled resonant converter. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
  • Küçük Resim Yok
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    Sliding mode PLL-PDM controller for induction heating system
    (Tubitak Scientific & Technological Research Council Turkey, 2021) Ozbay, Harun; Karafil, Akif; Oncu, Selim
    In this study, a sliding mode controlled phase locked loop (SMC-PLL) was developed for induction heating (IH) applications with a resonant inverter. PLL applications are widely used in induction heating applications to achieve zero voltage switching and zero current switching. In many PLL applications, the frequency tracking is too slow and unreliable. Therefore, a sliding mode controller was developed to provide robust and fast PLL. Furthermore, a pulse density modulation (PDM) control strategy was developed to work at the resonant frequency for all power levels. The PDM power control is a good solution for the design of high-frequency inverters because of a great reduction of switching losses and electromagnetic noise. The PDM pattern for the desired output power is determined according to the set temperature value of the work piece. The proposed system was simulated in PSIM and a 250-W laboratory prototype was implemented with operating frequency of 35-42 kHz.