Irfan Yazici

A FPGA based digital design training platform

The role of laboratories are very important in engineering education. In this paper FPGA based digital design training platform was designed for Electrical & Electronics Engineering undergraduate students. Training platform interface was created at Visual C# program. The system combines the hardware and software and students access to both software and hardware tools to practice, implement and test their designs in the laboratory environment. The main purpose of the system is to minimize the losing and damaging TTL components used in laboratory environment, to increase the students hardware and software abilities and creative senses.

Hardware-based simple, fast and accurate measurement of power system frequency using a hybrid system

All digital methods developed for frequency measurement suffer from one or more factors such as superimposed noise, non-linear static characteristics, high-order harmonics and slow response because of complex computations. The measurement speed of conventional analogue methods is constant and depends on the input signal frequency. Additionally, as a result of deviated and/or spurious zero-crossings caused by the DC component, noise and high-order harmonics in the AC waveform, it is hard to attain the desired accuracy with conventional analogue methods. In this study, a phase-locked loop and microcontroller-based hybrid frequency measurement method developed by the modification of conventional zero-crossing is presented. The input signal, with harmonics and noise, and the frequency can be measured in a fast and accurate way with the proposed method, whose real-time application is extremely simple; this is demonstrated in a comparable manner to the studies in the literature. The measurement method presented in this study is fast, cheap, reliable, accurate and suitable for real-time applications.

An application study about SMPS design and reduction of common mode noises

A switched-mode power supply (also called as switching-mode power supply, SMPS, or simply switcher) is an electronic power supply unit (PSU) that incorporates a switching regulator. This paper investigates SMPS design and a filter solution for common mode noises. At first, the design of an SMPS which has three outputs has been presented after that common mode noises have been determined and then these noises have been tried to be reduced by the filter. The experimental studies have shown that there is a considerable reduction in common mode noises thanks to designed filter.

Design of model-refence discrete-time sliding mode power system stabilizer

Power system stabilizers (PSSs) improve the dynamic stability of power systems by increasing the damping torque of the synchronous machines in the system. Over the last four decades, various approaches for the design of PSSs have been reported in the literature. Sliding mode controller is one of these approaches which has some advantages, such as the parameter insensitivity and the realization simplicity, over the other approaches. In this paper, as a new approach for design of the PSS, a model reference discrete time sliding mode controller (MRDSMC) is presented. The effectiveness and the robustness of the proposed MRDSMC based PSS is demonstrated by a number of studies. Similation results show that the proposed PSS performs better for less overshoot and less settling time compared with the conventional and LQR based stabilizers under normal load operation and the significant system parameter variation conditions.

Ayrık-zaman KKK, LQR ve PID kontrolör performanslarının alçaltıcı tip Da-Da dönüştürücü üzerinde kıyaslanması

Bu calismada, surekli-akim modunda calistirilan alcaltici tip Da-Da donusturuculer icin ayrik-zamanda uc farkli kontrolor tasarlanmis ve benzetim calismalari ile performanslari karsilastirmali olarak incelenmistir. Bu amacla oncelikle alcaltici tip Da-Da donusturucunun matematiksel modeli elde edilmis ve donusturucunun surekli-akim modunda calisabilmesi icin kritik enduktans degeri belirlenmistir. Daha sonra ayrik-zamanda uc ayri kontrolor; kayan kipli kontrolor, dogrusal karesel regulator ve oransal-integral-turev kontrolorleri tasarlanmis ve bu kontrolorlerin performanslari yerlesme zamani, asim ve bozuculara karsi dayaniklilik kriterleri acisindan benzetim calismalari ile karsilastirmali olarak incelenmistir.

Designing of 2-DOF PID control algorithm for magnetic levitation systems

Bu calismada, acik cevrim, kararsiz ve lineer olmayan ikinci dereceden bir yapida oldugu icin bir bircok kontrol problemine konu olan manyetik top askilama sistemine uygun 2 Serbestlik Dereceli PID kontrolcusu tasarlanmis ve geleneksel PID kontrolcusuyle kiyaslanmistir. Sistem fiziksel parametreler baz alinarak modellenmis ve uygun birer denge noktasi civarinda Tylor serisine acilarak lineerlestirilmistir. PID kontrol parametreleri, ikinci dereceden sistemler icin uygun bir yontem olan kok yerlestirme metoduyla belirlenmis ve ayni parametreler 2 serbestlik dereceli PID icin de kullanilmistir. Onerilen bu kontrol algoritmasi ileri yol kazanc parametrelerine sahip oldugu icin geleneksel PID kontrolcusune gore gecici hal performansinin daha da iyilestirilmesi mumkun olmaktadir. Geleneksel kontrolcuden kaynaklanan sisteme ait transfer fonksiyonundaki sifirlarin sebep oldugu asimlarin onune gecilmistir.

Sensorless double integral sliding mode MPPT control for the WECS

In this paper, a double integrator sliding mode controller (DISMC) via the mechanical sensorless maximum power point tracking (MPPT) method is suggested to extract maximum power from a wind energy conversion system (WECS). The controller is required to bring the system to the maximum power point reference generated by the MPPT method. However, the controller design for the WECS operated in a wide wind speed range is a challenging task due to its highly nonlinear behavior. In this study, to enhance the performance of the WECS, a voltage mode DISMC, which is not used before for the WECS, is offered. The dynamic performance of the proposed method, considering the different wind speed scenarios, is proved with the simulation studies. Additionally, the performance of the DISMC is compared with that of the conventional sliding mode controller for the same wind speed scenarios.

Yükseltici Tip DC-DC Dönüştücüler İçin Ayrık-Zaman Köntrolör Tasarımı

In this paper, a small signal model for the boost converter is obtained. Two digital controllers using pole placement technique and Linear Quadratic Optimal Regulator (LQR) methods are designed and applied to the boost converter. The compensated system’s operations and analysis are discussed and verified through MATLAB/Simulink simulation. Comparison between the two controllers related to the design methodology, implementation issues and transient measured performance is carried out.

Real time implementation of a digital controlled boost converter

This paper presents real time implementation of a digital controlled conventional boost converter works on the fixed frequency driven by the duty cycle control techniques. The digital controller, implemented using ADUC841 microcontroller, monitors the output voltage and calculate the error to determine the next duty cycle value. Simulation and experimental results indicates that the constructed PI controlled boost converter have good transient response as well as stable and accurate steady-state response during the drastically changes occur in input voltage and output load.

Real time implementation of hybrid sine wave reference generator based on PLL and DLT

A sine signal synchronous to the power system voltage signal is required in most power electronics based industrial applications. In this study, a phase locked loop (PLL) and direct look-up table (DLT) based hybrid sine oscillator is developed, and sinusoidal signals of the desired frequency that is synchronous to the reference input signal is generated in real time applications carried out with the developed oscillator.