Showing papers by "Mustafa Şekkeli published in 2016"

Improved control configuration of PWM rectifiers based on neuro-fuzzy controller

Abstract: It is well-known that rectifiers are used widely in many applications required AC/DC transformation. With technological advances, many studies are performed for AC/DC converters and many control methods are proposed in order to improve the performance of these rectifiers in recent years. Pulse width modulation (PWM) based rectifiers are one of the most popular rectifier types. PWM rectifiers have lower input current harmonics and higher power factor compared to classical diode and thyristor rectifiers. In this study, neuro-fuzzy controller (NFC) which has robust, nonlinear structure and do not require the mathematical model of the system to be controlled has been proposed for PWM rectifiers. Three NFCs are used in control scheme of proposed PWM rectifier in order to control the dq-axis currents and DC voltage of PWM rectifier. Moreover, simulation studies are carried out to demonstrate the performance of the proposed control scheme at MATLAB/Simulink environment in terms of rise time, settling time, overshoot, power factor, total harmonic distortion and power quality.

Advanced configuration of hybrid passive filter for reactive power and harmonic compensation

Abstract: Harmonics is one of the major power quality problems for power systems. The harmonics can be eliminated by power filters such as passive, active, and hybrid. In this study, a new passive filter configuration has been improved in addition to the existing passive filter configurations. Conventional hybrid passive filters are not successful to compensate rapidly changing reactive power demand. The proposed configure are capable of compensating both harmonics and reactive power at the same time. Simulation results show that performance of reactive power and harmonic compensation with advanced hybrid passive filter is better than conventional hybrid passive filters.

Performance analysis of electronic power transformer based on neuro-fuzzy controller

Abstract: In recent years, electronic power transformer (EPT), which is also called solid state transformer, has attracted great interest and has been used in place of the conventional power transformers. These transformers have many important functions as high unity power factor, low harmonic distortion, constant DC bus voltage, regulated output voltage and compensation capability. In this study, proposed EPT structure contains a three-phase pulse width modulation rectifier that converts 800 Vrms AC to 2000 V DC bus at input stage, a dual active bridge converter that provides 400 V DC bus with 5:1 high frequency transformer at isolation stage and a three-phase two level inverter that is used to obtain AC output at output stage. In order to enhance dynamic performance of EPT structure, neuro fuzzy controllers which have durable and nonlinear nature are used in input and isolation stages instead of PI controllers. The main aim of EPT structure with the proposed controller is to improve the stability of power system and to provide faster response against disturbances. Moreover, a number of simulation results are carried out to verify EPT structure designed in MATLAB/Simulink environment and to analyze compensation ability for voltage harmonics, voltage flicker and voltage sag/swell conditions.

A performance comparison of static VAr compensator based on Goertzel and FFT algorithm and experimental validation.

Abstract: The main objective of the present paper is to introduce a new approach for measuring and calculation of fundamental power components in the case of various distorted waveforms including those containing harmonics. The parameters of active, reactive, apparent power and power factor, are measured and calculated by using Goertzel algorithm instead of fast Fourier transformation which is commonly used. The main advantage of utilizing Goertzel algorithm is to minimize computational load and trigonometric equations. The parameters measured in the new technique are applied to a fixed capacitor–thyristor controlled reactor based static VAr compensation system to achieve accurate power factor correction for the first time. This study is implemented both simulation and experimentally.

Simulation Study on Power Factor Correction Controlling Excitation Current of Synchronous Motor with Fuzzy Logic Controller

Abstract: The correction of power factor in electric power systems is called reactive power compensation. A synchronous motor is used as a capacitive reactive power generator in compensation systems. It is less costly for an enterprise to use a synchronous motor as both mechanical power generator and power factor corrector, which increases their efficiency. There are various studies on increasing the efficiency, capacity and stability of a power system using power factor correction under different operating conditions. This study focuses on the power factor correction of the system by controlling the excitation current of the synchronous motor via fuzzy logic thanks to the asynchronous motor connected to the system.

Türkiye gün öncesi elektrik piyasasında rüzgar enerjisi ve pompaj depolamalı hidroelektrik santral için optimum teklif oluşturulması

Abstract: Elektrik sebekesindeki talep guc arttiginda enerji fiyatlari artmakta, sebekedeki talep guc azaldiginda enerji fiyatlari azalmaktadir. Bu sebeple, gunluk toplam gelirin arttirilmasi icin uretimlerin yuksek talep guc degerlerinin olustugu saatlere kaydirilmasi gerekmektedir. Ruzgar Enerjisi Santralleri (RES) kararsiz ve kontrol edilemeyen uretim karakteristigine sahiptirler. Bu sebeple RES uretimlerini zaman ekseninde kaydirabilmek icin enerji depolama sistemlerine ihtiyac duyulmaktadir. Bu calismada; Turkiye enterkonnekte elektrik sebekesine bagli dort adet Ruzgar Enerjisi Santrali (RES) ve bu santrallerin enerji depolama ihtiyacini karsilamak uzere dusunulmus bir Pompaj Depolamali Hidroelektrik Santral (PHES), Turkiye gun oncesi elektrik piyasasinda incelenmistir. Beraber enerji uretimi yapacak bu santrallerin gun oncesi piyasa tekliflerini optimize etmek uzere dogrusal programlama yontemi kullanilarak bir optimizasyon algoritmasi gelistirilmistir. Optimizasyon stratejisi ile isletilen santrallerin uretimleri ve gelirleri incelendiginde, RES’lerin tek basina isletilmesi ile kiyasla senelik gelirin %2.737 oraninda arttigi ve uretimlerin talep gucun yuksek oldugu saatlere buyuk oranda kaydirilabildigi gorulmustur.

Türkiyede Bir Rüzgar Enerjisi Santrali Üretim Karakteristiğinin Pompaj Depolamalı Hidroelektrik Santral ile Değiştirilmesi.

Abstract: It is known that Wind Power Plants (WPP) have variable and not fully forecastable characteristics. These characteristics of WPPs, make difficult to ensure energy production-consumption balance in their integrated grid. Studies in recent years within this scope put forward there is an energy storage system requirement to change this undesirable (distorting grid's energy balance) property of wind energy. In this study primarily we evaluate energy production of a WPP installed in Turkey. Then, power productions of a WPP are tried to be smoothed by means of Pumped Storage Hydro Power Plant (PHPP). Joint operation of PHPP and WPP implemented by two seperate schedules. 1) Operating two power plant as a base load power plant by producing constant energy. 2) Operation of two power plants that the production can track energy demand. When we analayse the results based on relieability index and energy sale income its seen that two power plants are more reliable in working like base load power plant mode, more profitable in load tracking mode.

Power Quality Analysis Of A Campus Field: Case Study For Avşar Campus Of Kahramanmaraş Sütçü İmam University

Abstract: Each passing day the use of power electronics based components have been increased because of rising the human's quality of life and development of technology. The increased use of these elements have been caused corruptions over the electricity power systems and thus it affects negatively the energy quality over power systems. Two parameters of power quality are harmonics and flicker. In this work; the measurements were taked the transformer’s low voltage side which feed buildings of faculty of forest and rectorship where in Avsar Campus of Kahramanmaras Sutcu Imam University by means of network analyzer. The figures which were formed through these measurement’s data were interpreted in terms of harmonics and flicker and necessary solutions were offered.

Price Forecasting Model for Turkish Day-Ahead Electricity Market Using Neural Network

Abstract: Day-ahead electricity market (DAM) price forecasts are crucial parameters for market participants to create their next – day generation plan. Accurate price forecasts help participant companies to increase their profit by shifting generation to high price occurred hours. In this study we developed a forecast model for Turkish energy market because country’s energy market mechanism hasn’t got price forecast module and there is no available accurate price forecasts. Architecture of model is based on feed forward back propagation neural network approach. Four year period real market data are used in train and test phases. Results of this study show that forecasts of proposed model have acceptable accuracy and the performance of the model strongly depends on the market demand and generation capacities.