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Analysis of grid connected wind power system
(Institute of Electrical and Electronics Engineers Inc., 2019) Bekiroğlu, Erdal; Yazar, Muhammed Duran
The importance of renewable energy sources has increased rapidly in recent years. Among these renewable energy sources, wind energy comes to leading due to its advantages such as clean, sustainable and cost-effective. Wind power energy source is an intermittent energy source. The power output can vary widely because of the random variables of wind speed. The wind turbine output is equal to wind speed's cube. The grid-connected wind power which includes many paralleled wind turbines, transformers and collection lines, will affect stability of the power system. In the present study, the grid-connected wind power system has been analyzed for 30 km, 120 km transmission lines where wind speeds are 6 m/s, 11 m/s, respectively. Simulation results and conclusions have been given for impact of wind speed and transmission line length on active power, reactive power, and power factor.
Asenkron motorlar için denetleyici tabanlı yol verme ve koruma rölesinin gerçekleştirilmesi
(2007) Bayındır, Ramazan; Demirbaş, Şevki; Irmak, Erdal; Bekiroğlu, Erdal
Bu çalışmada üç fazlı asenkron motorlar için koruma ve yıldız-üçgen yol verme rölesi PIC 16F877 denetleyicisi ile gerçekleştirilmiştir. Röle ile faz sırası, faz kopukluğu, düşük/yüksek gerilim kontrolü yapıldıktan sonra üç fazlı motora yıldız-üçgen yol verilmiştir. Klasik yol verme ve koruma röleleri ile karşılaştırıldığında, tasarlanan röle ile kullanılan eleman sayısı azalmış, fiziki yapı küçülmüş ve bağlantı karmaşası ortadan kaldırılmıştır. Ayrıca sayısal bir yol verme sistemi ve koruma rölesi sayesinde sistemin güvenirliği artırılmıştır.
Automatic synchronization unit for the parallel operation of synchronous generators
(Ieee, 2009) Bekiroğlu, Erdal; Bayrak, Alper
In this study, an automatic synchronization unit has been developed for the parallel connection of synchronous generators. Two synchronous generators are connected in parallel automatically with the developed control unit. Synchronous generators are also connected in parallel with the line. The voltages, frequencies, phase sequences and synchronism time data have been transferred to the microcontroller. These data are monitored and evaluated by the control algorithm coded into the microcontroller. Parallel operation of generators are realized automatically when all parallel connection conditions are occur. The system doesn't require additional measuring tools for monitoring and control processes. The developed automatic synchronization unit is fast, cost effective, reliable and precise to be used for monitoring, measurement and parallel operation of the synchronous generators.
Comparative study on mechanical properties of undoped and Ce-doped Bi-2212 superconductors
(Springer, 2013) Zalaoğlu, Yusuf; Bekiroğlu, Erdal; Doğruer, Musa; Yıldırım, Gürcan; Öztürk, Özgür; Terzioğlu, Cabir
This study discusses the mechanical performances of Bi1.8Sr2.0CexCa1.1Cu2.1Oy ceramics with x = 0, 0.001, 0.003, 0.005, 0.01, 0.03, 0.05 and 0.1 by way of Vickers microhardness (H-v) measurements performed at different applied loads in the range of 0.245-2.940 N. For the potential industrial applications, the important mechanical characteristics such as Vickers microhardness, elastic modulus, yield strength, fracture toughness and brittleness index values of the samples studied are extracted from the microhardness measurements. All the results obtained indicate that the Vickers hardness, Young's (elastic) modulus, yield strength, fracture toughness and brittleness index values suppress with the increment of the Ce concentration in the system as a consequence of the degradation in the connectivity between superconducting grains. The decrement in the H-v values with the applied load is attributed Indentation Size Effect behaviour of the samples studied. Moreover, the experimental results of Vickers microhardness measurements are estimated using the 5 different models such as Kick's law, proportional sample resistance model, modified proportional sample resistance model, elastic/plastic deformation model and Hays-Kendall approach. According to the results obtained from the simulations, Kick's law is not useful model to obtain information about the origin of the indentation size effect feature of the Ce-doped bulk Bi-2212 superconductors. On the other hand, the Hays-Kendall approach is determined as the most suitable model for the description of the mechanical properties of the superconducting samples. In addition, the bulk porosity analysis for the samples reveals that the porosity increases monotonously with the Ce inclusion in the Bi-2212, leading to the degradation of the grain connectivity.
Comparison of trapezoidal and sinusoidal pwm techniques for speed and position control of pms
(Vsb-Technical Univ Ostrava, 2020) Bekiroğlu, Erdal; Dalkın, Ahmet
In this article, speed and position controls of Permanent Magnet Synchronous Motor (PMSM) are performed by using a genetic algorithm-based controller. Hall Effect sensors have been used to obtain position data of the motor. Since Hall Effect sensors have been mounted, PMSM has been driven as a Brushless DC (BLDC) motor. Sinusoidal and trapezoidal current reference models have been used in the control system. The proposed control system has been operated for speed control as well as position control of the motor. The developed genetic-based speed and position control method has been tested for both trapezoidal and sinusoidal PWM commutation techniques. The results obtained from these commutation techniques have been compared. Speed and position results of the motor have been obtained under the different load and operating conditions. The results reveal that the proposed control system is reliable, robust and effective.
Degeneration of mechanical characteristics and performances with Zr nanoparticles inserted in Bi-2223 superconducting matrix and increment in dislocation movement and cracks propagation
(Springer, 2016) Akdemir, Ertuğrul; Pakdil, Murat; Bilge, Habibullah; Kahraman, Mehmet Fatih; Bekiroğlu, Erdal; Yıldırım, Gürcan; Öz, Muhammed
This study explains the role of Zr concentration level on mechanical characteristics and performance belonging to the bulk Bi-2223 superconducting materials by means of standard Vickers microhardness (H-v) measurements at different applied loads in the range of 0.245-2.940 N and evaluated theoretical calculations. The experimental measurement results obtained display that the mechanical performances regress with the increment of the Zr addition level due to the increased artificial disorders/damages/breaks/voids/cracks and irregular grain orientation distribution. In other words, the Zr addition accelerates both the dislocation movement and especially the cracks/voids propagation of as a consequence of the decrement in the Griffith critical crack length, being one of the most striking points deduced from this work. These vital findings are also favored by the extracted parameters of Young's modulus, yield strength, fracture toughness and brittleness index. Nevertheless, it is found that every sample studied exhibit typical indentation size effect (ISE) behavior due to the production of the elastic and plastic deformations simultaneously in the system. Moreover, the load dependent microhardness values are theoretically analyzed with the aid of six available models such as six available approaches: Meyer's law, proportional sample resistance model, modified proportional sample resistance model, elastic/plastic deformation, Hays-Kendall (HK) and indentation-induced cracking model for the first time. The results obtained show that the HK approach exhibits perfectly performance on the analysis of the mechanical characteristics of the superconducting materials exhibiting ISE behavior whereas the other models are inadequate to explain the load independent mechanical characteristics of the Bi-2223 system added by the Zr nanoparticles.
Design and double-stage optimization of synchronous reluctance motor for electric vehicles
(Taylor & Francis Inc, 2023) Bekiroğlu, Erdal; Esmer, Sadullah
In this study, a high-power synchronous reluctance motor (SynRM) was designed for the traction motor of electric vehicle (EV) and its double-stage optimization was performed. Genetic algorithm and sensitivity analysis methods were used to obtain the best design parameters. Double-stage optimization was carried out to minimize the torque ripple and obtain the targeted torque, speed, and power values of the SynRM. In the first stage, the genetic algorithm method was used to improve the design parameters of the stator and rotor. With the improved design parameters, it was observed that the torque ripple decreased. In the second stage, the sensitivity analysis method was used. In this method, the effect of changing the skew angle of the stator on the torque ripple was investigated. The performance of the designed motor was examined in the optimization process. It was observed that the targeted torque, power, speed, efficiency, and torque ripple minimization values are successfully achieved with the best stator and rotor parameters. The results showed that SynRM produces high torque and high power with high efficiency and low torque ripple over wide speed range. It is quite proper to use the designed SynRM as a traction motor of new generation electric vehicles.
Design and implementation of drive and control system for ultrasonic motor over power line communication
(Taylor & Francis Inc, 2024) Daldal, Nihat; Aytar, Oktay; Bekiroğlu, Erdal; Bal, Güngör
In this study, remote control application of an ultrasonic motor (USM) has been achieved over the power line communication (PLC) system. Fast, practical, affordable and effective operating mode is essential for the USM. This study aimed to develop an original, efficient, effective and economical method. Drive and control of USM control has been succeeded with the developed PLC control system. A two-phase high-frequency inverter, a power line transmitter, and a power line receiver circuits have been designed to drive and control of the ultrasonic motor. Required measurements are acquired from the power line to select the most suitable communication frequency and coupling circuit impedance for the PLC system. For the communication frequency and impedance value measurements the receiver and the transmitter circuits have been designed. The PLC-controlled system has been tested for different operating conditions of the ultrasonic motor. USM control has been accomplished over the existing power line without using extra cables and interfaces for communication. The obtained results show that the PLC-controlled system is practical, reliable, cost-effective, and feasible for the remote control of the USM. This research contributes a new and essential perspective for the PLC-based remote control studies in addition to the USM drive and control strategies.
Design and magnetic analysis of a grounding transformer compatible with wind power system
(IEEE, 2023) Demiral, Elif; Bekiroğlu, Erdal; Yazar, Muhammed Duran
The aim of this study is to design and magnetic analysis of a grounding transformer in order to prevent material damage caused by phase-ground faults that may occur in wind energy systems. A zig-zag transformer is designed with a new winding design technique, different from the traditional zig-zag transformer design. Due to the lack of analytical formulas, finite element analysis (FEA) is used to calculate leakage reactance of designed transformer. The designed zig-zag transformer is analyzed in the ANSYS Maxwell environment. The proposed grounding transformer for wind power systems is investigated in terms of 3-phase 3D leakage reactance, 1-phase 3D leakage reactance, core losses of 3D, core losses of 2D, and flux density. The obtained results showed that the designed zig-zag transformer is compatible with wind power systems.
Design of highly effective multilayer feedforward neural network by using genetic algorithm
(Wiley, 2020) Üstün, Oğuz; Bekiroğlu, Erdal; Önder, Mithat
This paper presents a highly effective and precise neural network method for choosing the activation functions (AFs) and tuning the learning parameters (LPs) of a multilayer feedforward neural network by using a genetic algorithm (GA). The performance of the neural network mainly depends on the learning algorithms and the network structure. The backpropagation learning algorithm is used for tuning the network connection weights, and the LPs are obtained by the GA to provide both fast and reliable learning. Also, the AFs of each neuron in the network are automatically chosen by a GA. The present study consists of 10 different functions to accomplish a better convergence of the desired input-output mapping. Test studies are performed to solve a set of two-dimensional regression problems for the proposed genetic-based neural network (GNN) and conventional neural network having sigmoid AFs and constant learning parameters. The proposed GNN has also been tested by applying it to three real problems in the fields of environment, medicine, and economics. Obtained results prove that the proposed GNN is more effective and reliable when compared with the classical neural network structure.
Design, Optimization, and Performance Improvement of Synchronous Reluctance Motor for Micro-Mobility Vehicles
(2023) Bekiroğlu, Erdal; Esmer, Sadullah
In this study, design, optimization, and performance improvement of a 2-kW synchronous reluctance motor (SynRM) have been performed for micro-mobility electric vehicles. The finite-element method has been used for analyses. At first, SynRM has been designed in Ansys Maxwell with initial stator and rotor parameters. Then, stator and rotor parameters of SynRM have been optimized by using a genetic algorithm. Thus, the torque capacity of SynRM has been increased and the torque ripple has been reduced. In addition, the performance of optimized SynRM has been investigated by adding magnets to its rotor. Designed SynRM and permanent magnet-supported SynRM have been compared. It has been seen that the permanent magnet-supported SynRM produces higher torque with higher efficiency and less torque ripple. Simulation results proved that the permanent magnet-supported SynRM can be used successfully in micro-mobility class electric vehicles.
Examination of effective nucleation centers for flux pinning of vortices and optimum diffusion annealing temperature for Au-diffusion-doped Bi-2212 polycrystalline compound
(Elsevier Science Sa, 2016) Sarıtekin, Namık Kemal; Pakdil, Murat; Bekiroğlu, Erdal; Yıldırım, Gürcan
This comprehensive study declares experimentally the effect of diffusion annealing temperature in a range of 600 degrees C-850 degrees C on the electrical, superconducting and microstructural properties of the Au-diffusion-doped Bi-2212 polycrystalline compounds with the aid of the available experimental methods such as bulk density, dc resistivity (rho-T), transport critical current density (J(c)), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and electron dispersive X-ray (EDX) measurements. The experimental findings of the dc electrical resistivity and XRD investigations present that the Au impurities are effectively entered into the crystalline structure of the Bi-2212 system. In fact, the EDX examinations confirm that the Au impurities may mostly be substituted for the Sr-sites in the Bi-2212 crystal matrix due to the increase of electronegativity. Besides, the J(c) measurements present that highly dispersed Au impurities with higher electronegativity bind tightly to form the effective nucleation centers through the intra-grain and inter-grain boundaries for the flux pinning of the vortices in the Bi-2212 crystal structure. Furthermore, it is observed that the vital characteristics, being responsible for newly/novel and feasible market areas for the universe economy, improve significantly with the increment in the diffusion annealing temperature up to the value of 800 degrees C as a consequence of the retrogression in the disorders, dislocations, defects, lattice strains, misorientations and local structural distortions in the Cu-O-2 consecutively stacked layers, leading to the development of the metastability (enhancement of the hole trap energy) belonging to the superconducting materials studied. However, after the critical temperature point, the properties recrudesce dramatically due to the penetration of excess Au foreign impurities in the Bi-2212 crystal structure. In more details, the XRD measurement findings display that the diffusion annealing temperature promotes significantly the high phase as a consequence of the increment in both the average crystallite size and c-axis length or decrement in the constant parameter a. In this respect, the solid compound produced at the annealing temperature of 800 degrees C obtains the maximum (minimum) c-axis length of 35.43 angstrom (5.32 angstrom) and average grain size of 68.7 nm. Similarly, the same sample exhibits the smoothest and densest surface morphology with the best interaction between the superconducting grains and largest crystalline distribution. Finally, the highest T-c(onset) and T-c(offset) values are noted to be about 89.78 K and 89.01 K, respectively. This is attributed to the fact that the Au nanoparticles penetrated transit from inherently overdoped nature of the Bi-2212 compound to optimally doped state. To sum up, the annealing temperature of 800 degrees C favors the Bi-2212 superconducting ceramics for usage in the large scale applications. (C) 2016 Elsevier B.V. All rights reserved.
Experimental Analysis of Energy Quality at Campus Network-Case Study: Bolu Abant Izzet Baysal University (Engineering Building)
(2020) Bekiroğlu, Erdal; Yildiz, Haluk
In this study energy quality of university campus network have been analyzed experimentally. The experimentaltests and measurements have been implemented at Engineering Building of the Bolu Abant Izzet BaysalUniversity (Turkey). Energy quality analysis has been performed by making current, voltage, frequency, powerfactor, harmonics, neutral-earth voltage measurements at the main distribution board of the EngineeringBuilding. Besides, active power filter has been connected and its effects examined. The reasons for the energyquality problems on the electric power distribution system of the campus building have been revealed andrequired solutions have been offered.
Experimental investigation of input-output characteristics of a travelling-wave ultrasonic motor
(Springer, 2008) Bekiroğlu, Erdal; Bal, Güngör
Speed, position and load characteristics of the ultrasonic motor is considerably influenced from the input characteristics such as driving frequency, magnitude and phase difference of phase voltages. Input and output characteristics of a traveling-wave ultrasonic motor have been investigated from the experimental point of view in the present study. For this aim, a half-bridge serial-resonance inverter based drive system has been designed and then implemented. The inverter is featured with pulse width modulation and pulse frequency modulation techniques. The frequency, amplitude and phase angle of two-phase sinusoidal output of the driver has been designed to be changed for the control purpose. Then the measuring circuits and tools have been set up to obtain required measurements. Input characteristics such as duty ratio of control signal-dc reference voltage, dc reference voltage-driving frequency and output characteristics such as driving frequency-rotor speed, driving frequency-feedback voltage, phase voltage-rotor speed are obtained from the experiments. Also load characteristics are studied with experiments. Afterwards these characteristics are discussed in details. This study gives a systematical experimental approach in order to demonstrate operating and control principles and characteristics of the travelling-wave ultrasonic motor.
Fault-ride through improvement of DFIG under symmetrical/asymmetrical voltage dips
(Taylor & Francis Inc, 2023) Bekiroğlu, Erdal; Yazar, Muhammed Duran
In this study, improving fault-ride through capacity of the DFIG under symmetrical and asymmetrical voltage dips has been investigated. Initially, a crowbar protection circuit has been designed for the rotor side converter (RSC). With the help of the crowbar, the fault ride-through (FRT) ability of the wind energy conversion systems (WECS) has been increased, while the capacitors, rotor windings, and converters are protected from critical damage caused by the voltage dip. Then, the crowbar has been equipped with a fuzzy logic controller (FLC) to increase the FRT capacity. The switching time of the crowbar circuit has also been improved to protect the WECS from this serious damage. The suggested WECS has been designed and analyzed in Matlab/Simulink under symmetrical/asymmetrical voltage dips. DC bus voltage, electromagnetic torque, grid currents, crowbar current, and terminal voltage results of DFIG have been obtained. The simulation results of the DFIG have been compared. The results have also been contrasted with related studies. The obtained results demonstrated the robustness, applicability, and dependability of the suggested system.
Fuzzy logic based DSP controlled servo position control for ultrasonic motor
(Pergamon-Elsevier Science Ltd, 2004) Bal, Güngör; Bekiroğlu, Erdal; Demirbaş, Şevki; Çolak, İlhami
In this paper, position control of an ultrasonic motor was implemented on the basis of fuzzy reasoning. A digitally controllable two phase serial resonant inverter was developed to drive the ultrasonic motor by using a TMS320F243 digital signal processor. The driving frequency was used as a control input in the position control loop. The position characteristics obtained from the proposed drive and control system were demonstrated and evaluated by experiments. The experimental results verify that the developed position control scheme is highly effective, reliable and applicable for the ultrasonic motor.
A highly effective load adaptive servo drive system for speed control of travelling-wave ultrasonic motor
(Ieee-Inst Electrical Electronics Engineers Inc, 2005) Bal, Güngör; Bekiroğlu, Erdal
This paper presents a highly effective load adaptive drive system to control the speed of a travelling-wave ultrasonic motor. The motor driver was built based on the two-phase high-frequency inverter using the. mechanical resonant frequency of the ultrasonic motor. To digitally control the drive system, a TMS320F243 digital signal processor was adapted to the driver. The developed system includes two feedback loops; speed control loop and feedback voltage-resonant frequency tracking loop. The driving frequency was used as a control input to control the motor. Direct pulse-width modulation (PWM) control was used to obtain the required driving frequency. The developed drive system was experimentally tested under several operating conditions. The obtained results demonstrated the effectiveness of the drive system for high performance drive applications.
Implementation of indirect vector control to induction motor with zero current transition inverter
(Ieee, 2009) Bal, Güngör; Öztürk, Nihat; Bekiroğlu, Erdal
In this study, the speed control of the vector controlled induction motor was implemented by using hard switching and soft switching inverters. A TMS320F243 digital signal processor was used to implement control algorithm during practical implementation. With the use of the vector control, complex structure of the controller is simplified, and dependence to variations of the motor parameters is reduced. In order to reduce switching losses arising mainly from hard switching method a soft switching method was designed and implemented. Switching signals of the auxiliary switches are independent from main switching signals in the proposed method. The method can be applied to the puls width modulation (PWM) inverter by setting up proper switching strategies.
Improving energy efficiency in climatic test chambers with deep learning and absolute humidity methods
(IEEE, 2023) Bekiroğlu, Erdal; Karaca, Hakan
Climatic test chambers are devices used to simulate environmental conditions for the testing and verification of products in various industries. However, these chambers can consume significant amounts of energy, resulting in high operating costs and environmental impacts. Therefore, the need to optimize the energy efficiency of climatic test chambers while maintaining their performance is becoming increasingly important. In this paper, we will discuss the control method for humidity testing by calculating the use of the LSTM algorithm instead of the classical control method PID to control climatic test chambers to improve energy efficiency and the control method based on absolute humidity instead of relative humidity. In particular, we harness the power of artificial neural networks to reduce energy consumption and improve control of climatic test chambers based on various input parameters such as temperature, humidity, and test duration. By changing the control methods, we aim to increase efficiency and make it more suitable and efficient for smart grid systems.
Improving fault ride through capability of DFIG with fuzzy logic controlled crowbar protection
(Institute of Electrical and Electronics Engineers Inc., 2022) Bekiroğlu, Erdal; Yazar, Muhammed Duran
Doubly fed induction generators (DFIG) are sensitive to intense disturbances in the grid. Various methods such as crowbar protection circuits are used to increase the fault ride-through (FRT) capability of DFIGs. Crowbar is one of the most important protection methods used to protect the rotor side converter, rotor windings, and capacitors in the wind energy conversion system (WECS) from the damage of overcurrent/overvoltage. Setting the timing of the crowbar switch excellently is significant for the stability of the grid and the efficiency of the WECS. In this study, a Fuzzy logic controller (FLC) block has been added to control the crowbar switch to improve the timing of the crowbar and improve the FRT capability of the WECS. The performance of DFIG-based WECS with FLC under symmetric voltage dip was investigated by using Matlab/Simulink environment at a constant wind speed of 12 m/s. DC bus voltage, crowbar current, the terminal voltage of DFIG, and electromagnetic torque results were obtained. The results of the crowbar with the proposed controller and the results of the crowbar without FLC were compared. The results revealed that the proposed system is reliable, proper, and prevailing for the grid-connected DFIG under grid fault conditions. © 2022 IEEE.

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