Yazar "Karabacak, Murat" seçeneğine göre listele

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    Chattering free robust control of LCL filter based shunt active power filter using adaptive second order sliding mode and resonant controllers
    (Elsevier Sci Ltd, 2016) Kale, Murat; Karabacak, Murat; Kruschel, Wolfram; Kılıç, Fuat; Zacharias, Peter
    This paper proposes a new robust adaptive controller for LCL filter based shunt active power filters in order to solve the control problems of high overshoot and large settling time in the DC link voltage. To this end, the second order sliding mode with the adaptive gain super-twisting control law and proportional-resonant controllers with active damping are used in the DC bus voltage control loop and d-q axis current control loops respectively. The control objectives are fourfold: (I) driving the DC bus voltage to a reference signal; (ii) forcing the d-q axis current errors to zero; (iii) assuring a satisfactory power factor correction and a high harmonic performance in relation to the AC source; and (iv) eliminating the chattering effect. In the closed loop control system, three phase grid currents, LCL capacitor currents and the DC link voltage are available for feedback. As a result, the proposed controller has the advantages of zero overshoot response and fast acting chattering-free behavior. Results of experimental studies prove that the proposed control system guarantees to track reference signals with a high harmonic performance despite external disturbance uncertainties. (C) 2015 Elsevier Ltd. All rights reserved.
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    Design, modelling and simulation of a new nonlinear and full adaptive backstepping speed tracking controller for uncertain PMSM
    (Elsevier Science Inc, 2012) Karabacak, Murat; Eskikurt, Halil İbrahim
    In this study, a new nonlinear and full adaptive backstepping speed tracking control scheme is developed for an uncertain permanent magnet synchronous motor (PMSM). Except for the number of pole pairs, all the other parameters in both PMSM and load dynamics are assumed unknown. Three phase currents and rotor speed are supposed to be measurable and available for feedback in the controller design. By designing virtual control inputs and choosing appropriate Lyapunov functions, the final control and parameter estimation laws are derived. The overall control system possesses global asymptotic stability; all the signals in the closed loop system remain bounded, according to stability analysis results based on Lyapunov stability theory. Further, the proposed controller does not require computation of regression matrices, with the result that take the nonlinearities in quite general. Simulation results clearly exhibit that the controller guarantees tracking of a time varying desired reference speed trajectory under all the uncertainties in both PMSM and load dynamics without singularity and overparameterization. The results also show that all the parameter estimates converge to their true values on account of the fact that reference speed signal chosen to be sufficiently rich ensures persistency of excitation condition. Consequently, the proposed controller ensures strong robustness against all the parameter uncertainties and unknown bounded load torque disturbance in the PMSM drive system. Numerical simulations demonstrate the performance and feasibility of the proposed controller. (C) 2011 Elsevier Inc. All rights reserved.
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    An Implementation of Induction Motor Drive with Half Wave Symmetrical SVM
    (Praise Worthy Prize Srl, 2011) Karabacak, Murat; Eskikurt, Halil İbrahim; Öztürk, Ali
    In this study, the half wave symmetrical Space Vector Pulse Width Modulation (SVM) is employed in a v/f controlled three phase induction motor drive system with the intention of reducing harmonic components of the three phase currents feeding to the induction motor windings without using any artificial intelligence algorithm. The most important part of induction motor drives is the inverter. Inverters are used to convert direct current to alternative current and to modulate amplitude and frequency of the converted alternative current. For control of inverters, various Pulse Width Modulation (PWM) methods have been proposed so far. Among them, SVM method is the most frequently preferred method since it has certain advantages over the other PWM methods. These are primarily efficient DC-bus voltage utilization, high harmonic peiformance and low switching losses. However, conventional SVM does not have half wave symmetry and hence even order harmonics appear in the output voltages of the inverter. The half wave symmetrical SVM can be achieved by utilizing a specific switching sequence and hence provides better harmonic performance while preserving all the other advantages of the conventional SVM. In this study, the SVM with such switching pattern is applied to an induction motor drive system in order to minimize harmonic components, especially low order harmonics, of the three phase currents feeding the motor windings. Copyright (C) 2011 Praise Worthy Prize S.r.l. - All rights reserved.
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    LLCL Filter Design for Grid Connected Inverters; a Detailed Performance Analysis
    (Gazi Univ, 2016) Karabacak, Murat; Kılıç, Fuat; Saraçoğlu, Bilal; Boz, Ali Fuat; Ferikoğlu, Abdullah
    Currents injected into grid need to have a total harmonic distortion below 5% in grid connected inverters. To this aim, output filters are employed. For these filters, design conditions other than total harmonic distortion for voltage drop over the filter and reactive power consumption of the filter have to be also fulfilled. In literature, some filter schemes have been proposed to satisfy these conditions. In this study, the most important filter types are handled and a performance analysis between L, LCL and LLCL filter was implemented. Consequently, it is concluded that LLCL filter has higher performance and lower cost, on the condition that some risky points are considered.
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    A novel hysteresis band current controller scheme for three phase AC chopper
    (Elsevier Sci Ltd, 2013) Kale, Murat; Karabacak, Murat; Saraçoğlu, Bilal
    This paper presents the application of the hysteresis band current controller (HBCC) technique to the three phase pulse width modulation (PWM) AC chopper used for the purpose of controlling the magnitude of the sinusoidal currents and voltages applied to an AC load. If the HBCC technique used in the inverters is directly employed in the three phase PWM AC chopper, it causes the AC chopper to fail to provide balanced three phase sinusoidal currents for a three phase AC load. In return, this situation leads some unavoidable and serious faults to occur in the hardware of the three phase PWM AC chopper. In respect to this case, the detailed analysis expressing the related faults is presented. Consequently, for the first time, a novel HBCC technique overcoming these faults is proposed for the three phase PWM AC chopper. The proposed method is tested under various operating conditions and a very precise control performance is achieved. Simulation results prove the feasibility and validity of the proposed method. (C) 2012 Elsevier Ltd. All rights reserved.
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    Sensorless control application of PMSM with a novel adaptation mechanism
    (Springer, 2018) Dursun, Mustafa; Boz, Ali Fuat; Kale, Murat; Karabacak, Murat
    This paper proposes a novel adaptation design to replace the classical proportional-integral controller used in model reference adaptive system (MRAS) speed estimation. The proposed adaptation scheme is an association of two fuzzy units. The rules of each module were obtained by user experience and numerical data. In the traditional fuzzy logic controllers, the computational complication enhances with the attributes of the system variable quantities; the number of rules increases incrementally while the number of control variables increases. This negatively affects the response time of the system. This novel design was deduced to reduce the number of rules for a linear function of system variables. By this way, the response of the system became faster. Detailed simulation and experimental results were obtained for comparison of this novel method with traditional MRAS techniques. The results showed that the proposed method was faster in speed tracking and exhibited higher prediction accuracy and less oscillation than the traditional method. Thus, the proposed MRAS method was clearly seen to be applicable and reliable.
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    A SOGI Based Band Stop Filter Approach for a Single-Phase Shunt Active Power Filter
    (Institute of Electrical and Electronics Engineers Inc., 2018) Kale, Murat; Akar, Furkan; Karabacak, Murat
    Control of shunt active power filter (SAPF) requires a cascaded control structure as inner current closed loop followed by outer voltage control loop. The inner current control loop is responsible for tracking of a reference current while the outer voltage loop regulates DC bus voltage to a fixed value. Dynamic performance of the DC bus voltage regulation suffers from the adverse effects such that harmonic currents produced by SAPFs lead to fluctuations in DC bus voltage at certain harmonic frequencies. This causes SAPF to produce additional harmonic components, since the outer voltage loop deals with only fundamental waves where the fluctuations should not appear. This study proposes a DC bus voltage regulation methodology based on a Second Order Generalized Integrator (SOGI) acting as a band-stop filter with the aim of increasing the voltage regulation performance in the steady state. The proposed filter does not affect the transient response thanks to that it only suppresses the harmonic-induced fluctuations in DC bus voltage. Through a simulation study, the proposed methodology is validated, and the results prove the performance and feasibility of the proposed filter. © 2018 IEEE.
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    A SOGI Based Band Stop Filter Approach for a Single-Phase Shunt Active Power Filter
    (Ieee, 2018) Kale, Murat; Akar, Furkan; Karabacak, Murat
    Control of shunt active power filter (SAPF) requires a cascaded control structure as inner current closed loop followed by outer voltage control loop. The inner current control loop is responsible for tracking of a reference current while the outer voltage loop regulates DC bus voltage to a fixed value. Dynamic performance of the DC bus voltage regulation suffers from the adverse effects such that harmonic currents produced by SAPFs lead to fluctuations in DC bus voltage at certain harmonic frequencies. This causes SAPF to produce additional harmonic components, since the outer voltage loop deals with only fundamental waves where the fluctuations should not appear. This study proposes a DC bus voltage regulation methodology based on a Second Order Generalized Integrator (SOGI) acting as a band-stop filter with the aim of increasing the voltage regulation performance in the steady state. The proposed filter does not affect the transient response thanks to that it only suppresses the harmonic-induced fluctuations in DC bus voltage. Through a simulation study, the proposed methodology is validated, and the results prove the performance and feasibility of the proposed filter.
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    Speed and current regulation of a permanent magnet synchronous motor via nonlinear and adaptive backstepping control
    (Pergamon-Elsevier Science Ltd, 2011) Karabacak, Murat; Eskikurt, Halil İbrahim
    This paper proposes a new speed and current control scheme for a Permanent Magnet Synchronous Motor (PMSM) by means of a nonlinear and adaptive backstepping design. All the parameters in both PMSM and load dynamics are considered unknown. It is assumed that all state variables are measurable and available for feedback in the controller design. The final control and parameter estimation laws are derived by the design of the virtual control inputs and the Lyapunov function candidate. The overall control system is asymptotically stable according to stability analysis results based on Lyapunov stability theory. Simulation results clearly show that the controller guarantees tracking of a time varying reference speed owing to the fact that the speed and current tracking errors asymptotically converge to zero despite all the parameter uncertainties/perturbations and load torque disturbance variation. Numerical simulations reveal the performance and feasibility of the proposed controller. (C) 2011 Elsevier Ltd. All rights reserved.
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    Üç-fazlı asenkron motorun mikrodenetleyici tabanlı açık çevrim skaler hız denetimi
    (Düzce Üniversitesi, 2008) Karabacak, Murat; Saraçoğlu, Bilal
    Asenkron motorların düşük maliyet, az bakım gerektirme, dayanıklılık ve yüksek verim gibi özellikleri nedeniyle, asenkron motor sürücüleri (ayarlanabilir hızlı sürücüler) günümüz endüstrisinde çok yaygın olarak kullanılmaktadır. Bilindiği gibi, asenkron motor sürücülerinin en önemli kısmını eviriciler oluşturmaktadır. Evirici, doğru gerilimden alternatif gerilim elde etmek ve bu alternatif gerilimin genlik ve frekansını denetlemek amacıyla kullanılmaktadır. Evirici ile bu işlemlerin gerçekleştirilmesi için çeşitli darbe genişlik ayarı (DGA) yöntemleri kullanılmaktadır.Eviriciler beslenme şekillerine göre gerilim ara devreli (GADE) ve akım ara devreli (AADE) olmak üzere iki ana sınıfa ayrılmaktadır. Asenkron motorların hız denetimi için genellikle GADE kullanılmaktadır. Eviricilerin denetiminde kullanılan DGA yöntemleri, eviricinin çıkış performansını doğrudan etkilemektedir. DGA yöntemlerinin en çok bilineni sinüzoidal darbe genişlik ayarı (SDGA) yöntemidir. Mikroişlemci teknolojisindeki gelişmeler sayesinde, uzay vektör darbe genişlik ayarı (UVDGA) yöntemi, günümüzde en çok kullanılan DGA yöntemi haline gelmiştir. Bu yöntem, SDGA yöntemi ile kıyaslandığında, daha verimli doğru akım (DA) bara gerilimi kullanımı, harmonik performansı ve düşük anahtarlama kayıpları gibi belirli üstünlüklere sahiptir.Bu tez çalışmasında, tipik bir üç-fazlı asenkron motorun GADE kullanılarak SDGA ve UVDGA yöntemleri ile mikrodenetleyici tabanlı açık çevrim skaler hız denetimi deneysel olarak gerçekleştirilmiştir. Her iki yöntemde, evirici çıkışındaki faz gerilimi ve hat akımları Hall-effect gerilim ve akım algılayıcıları ile ölçülerek örneklenmiştir. Elde edilen sonuçlardan, her iki yöntemdeki; gerilim ve akımdaki harmonik dağılımları, Toplam Harmonik Bozunum (THB)' lar ve temel dalga genlikleri birbirleri ile karşılaştırılmıştır. Deneysel çalışmalar sonucunda, UVDGA yönteminin SDGA yöntemine göre daha üstün harmonik performansına ve daha verimli DA bara gerilimi kullanımına sahip olduğunu görülmüştür.