Erdal Irmak

Gazi University · Department of Electrical and Electronic Engineering

In this paper, an event-triggered distributed secondary control, along with an energy management algorithm, was developed to ensure the voltage stability and power management of a DC microgrid containing batteries and renewable energy sources, such as PV systems and wind turbines. The energy management algorithm, employing fuzzy logic control, gove...

Although distributed secondary control helps control microgrids, it can provide insufficient performance in some cases where the system includes both renewable energy sources (RESs) and energy storage systems (ESSs). Therefore, an improved distributed secondary control structure is proposed in this study to improve efficiency and reliability in isl...

The growing interest in electric vehicles (EVs) as a solution to the environmental challenges and scarce energy resources, has created a myriad of challenges and opportunities. EVs operate on clean energy sources making them energy-efficient and sustainable. Nevertheless, the adoption of this mode of transport depends on finding a satisfactory reso...

Electric vehicles (EVs) have emerged as a promising solution to address environmental concerns and transform the transportation sector. This paper examines the state-of-the-art EVs, encompassing their history, definition, and different types. The advantages and limitations of each type are compared and contrasted, providing insights into their uniq...

This paper provides a comprehensive review of the future digitalization of microgrids to meet the increasing energy demand. It begins with an overview of the background of microgrids, including their components and configurations, control and management strategies, and optimization techniques. It then discusses the key digital technologies that can...

This paper provides a comprehensive overview of organic photovoltaic (OPV) cells, including their materials, technologies, and performance. In this context, the historical evolution of PV cell technology is explored, and the classification of PV production technologies is presented, along with a comparative analysis of first, second, and third-gene...

The electric power system is undergoing a significant transformation driven by advances in digital technologies. This article provides a comprehensive and detailed analysis of recent advances and the future outlook of electric power systems, with a particular emphasis on the impacts of digital transformation. By conducting a thorough examination of...

The use of renewables can make it more challenging to maintain a balance between supply and demand in microgrids due to their variable generation profiles. To address this issue, microgrids can be designed to be grid-interactive or to include energy storage units, or both. Additionally, demand-side management (DSM) strategies can be implemented to...

The power efficiency of photovoltaic energy systems mainly depends on climatic conditions such as solar irradiation and temperature. Therefore, several types of maximum power point tracking (MPPT) algorithms have been proposed to get the maximum efficiency. However, traditional algorithms perform insufficient response for reaching global maximum po...

A comprehensive and comparative review of control strategies for power-sharing operation in DC microgrids are presented in the paper. Since a microgrid consists of distributed generation sources and energy storage units, a control layer is required to manage the power-sharing operation between them. For this purpose, the control schemas used in DC...

The power system inertia based on the kinetic energy stored in synchronously connected rotating machines has a crucial effect on the frequency stability. As long as the use of renewables is increased, the share of conventional generators in electrical energy generation is decreased. Thus, the existing rotational inertia in the power system is reduc...

İnternet ve bilişim sistemleri üzerinde işlenen suçları tespit etmek amacıyla gerçekleştirilen adli bilişim incelemelerinin önemi, her geçen gün daha iyi anlaşılmaktadır. Bu minvalde suç ve suçlunun tespiti konusunda hukuka uygun dijital delillerin elde edilmesinin önemi çok büyüktür. Adli bilişim incelemelerinde, birçok farklı yöntem ile dijital d...

Covid-19, ilk olarak Aralık 2019’da Çin’de görülen bir virüs olmakla birlikte yayılımı ve şiddeti nedeniyle 11 Mart 2020’de Dünya Sağlık Örgütü tarafından küresel salgın olarak tanımlanmıştır. Aynı tarihte Türkiye’de de ilk vakanın görülmesiyle alınan yerinde ve zamanında önlemler sayesinde salgın eğrisindeki yükselişin önlenmesinde büyük bir başar...

Bu çalışmada, kablosuz ağlarda gerçekleştirilen şifre kırma saldırılarının ve Linux tabanlı sunucu sistemlerine yönelik önemli bir tehdit olan SSH kaba kuvvet saldırılarının, oluşturulan uygulama ortamlarında deneysel olarak test ve analizi gerçekleştirilmiştir. Ayrıca SSH kaba kuvvet saldırılarının, ELK-SIEM sistemi ile gerçek zamanlı ve ilişkisel...

Since renewable energy sources such as PV and wind provide intermittent energy generation, this paper presents an advanced DC/DC converter that is able to set its operational mode automatically to either multi-input multi-output (MIMO) or single-input multi-output (SIMO) depending on the input source conditions. Power flow is controlled through the...

Haberleşme, enerji, ulaşım ve sağlık hizmetleri gibi merkezi altyapı sistemleri, ülkeler için kritik altyapı sayılmaktadır. Bu sistemlerin yönetimini sağlayan operatörlerin yorgunluk durumları son derece önem arz etmektedir. Özellikle merkezi SCADA sistem operatörlerinin kısa süreli bir dalgınlık veya dikkatsizlikleri, ciddi bir olayın veya alarmın...

Abstract— Due to the nature of renewable energy, the variability in generation is high. The grid operator experiences operational concerns arising from the variable generation. In this study, distribution and differences of power angle in the grid are discussed and the effects of wind energy generation changes on power angles are analyzed in detail...

In this study, multi-input multi-output DC/DC converter topology is presented for both multisource operation and voltage unbalancing of Neutral Point Clamped (NPC) inverters. Multisource operation is provided with multi-input feature of proposed converter model. The unbalanced capacitor voltages in NPC inverter leading to increase the harmonics are...

In this study, Perturb and Observe Maximum Power Point Tracking (P&O MPPT) algorithm and Model Predictive Control (MPC) algorithm are combined to improve the dynamic performance of the control structure of boost converters used in renewable energy systems. For this purpose, a digital control method that does not need any comparator is developed. Th...

Electrical energy generation, transmission and distribution systems are evaluated in terms of national security dimension and defined as critical infrastructures. Monitoring and controlling of these systems are provided by Industrial Control Systems (ICS) or Supervisory Control and Data Acquisition (SCADA) systems. According to the latest advances...

Supervisory control and data acquisition (SCADA) systems play an important role in electrical power systems, which is one of the most critical infrastructures. They usually include digital controllers like PLCs to realize the automation of electromechanical processes and to accomplish the real time services. Ensuring a secure communication between...

This study focuses on smart home applications those especially use the wireless sensor networks to ensure the communication between the home devices and the central control unit. For this purpose, a prototype smart home network is designed which consists of some basic devices like refrigerator, television, washing machine etc. and also ZigBee nodes...

Design and simulation of a new inverter scheme are reported in the paper. The inverter is especially developed for an axial flux permanent synchronous generator (AFPMSG), which can be used for low power wind energy systems. The system includes a battery charge unit in addition to the inverter. Initially, the permanent magnet synchronous generator (...

This study presents an advanced computer interactive system for automatic parallel connection of synchronous generators and load sharing control between them. Because of its high operation speed and precision, a dsPIC microcontroller has been used in the study to control the conditions for paralleling and then to realize the connection, to transfer...

Bilgi güvenliği alanında risk değerlendirmesi siber saldırılara karşı alınacak önlemlerin en başlarında yer almaktadır. Bunun gerçekleştirilebilmesi için tehdit türlerinin çok iyi analiz edilmesi gerekmektedir. Bu çalışmada, kritik bilgi sistemlerine yönelik siber saldırı gerçekleştiren saldırganların profilleri incelenmiş, saldırı ağacı modeliyle...

Reactive power compensation of dynamic loads is one of the most important topics in electrical power systems. Therefore, various compensation techniques are continuously being developed in order to improve the power quality. In this context, this paper deals with the simulation and the analysis of a powerful Fixed Capacitor-Thyristor Controlled Rea...

Smart homes can be defined as homes which can satisfy the needs of comfort with the help of wireless modules. The smart home technologies make the daily life easier and offers safer, more comfortable and economic life spaces. The smart home systems allow the user to monitor and also control all electronic and electrical devices in the house. In thi...

Recently, growing electrical energy market and increasing integration of renewable energy sources (RES) in power systems have lead to new challenges on network planning step and operation, thus it is required to investigate and analyze properly the impacts of integrated RES on the power system. In this paper, the electricity transmission network wi...

This study presents integration of a real-time energy monitoring and control system with an advanced reactive power compensation unit based on fixed capacitor-thyristor controlled reactor (FC-TCR). Firing angles of the thyristors located in the FC-TCR are controlled by a microcontroller in order to keep the power factor within the limits. Electrica...

Bilgi güvenliği alanında risk değerlendirmesi siber saldırılara karşı alınacak önlemlerin en başlarında yer almaktadır. Bunun gerçekleştirilebilmesi için tehdit türlerinin çok iyi analiz edilmesi gerekmektedir. Bu çalışmada, kritik bilgi sistemlerine yönelik siber saldırı gerçekleştiren saldırganların profilleri incelenmiş, saldırı ağacı modeliyle...

Günümüzde birçok endüstriyel uygulamada mikrodenetleyici tabanlı kontrol ve izleme sistemleri kullanılmaktadır. Bu çalışmada, son zamanlarda kullanımı gittikçe yaygınlaşmakta olan dsPIC (Digital Signal Controller) mikrodenetleyicisi ele alınmıştır. dsPIC, özellikle yüksek hız ve tepki zamanı gerektiren uygulamalarda düşük maliyetli ve etkili çözüml...

This paper presents, a fault simulation on a microgrid consisting of a wind turbine, a solar panel and fuel cell. The power produced by different sources is combined on the same DC bus and converted to AC form using a three phase inverter in order to transfer it to 3-phase AC load. The system takes some precautions against some undesired situations...

This study introduces a novel and powerful speed control system with computer interface for wound-rotor induction machines (WRIM). In order to improve the sensitivity and stability of the control process, a high-speed digital signal processor (DSP) is used as the main controller. A serial resistor is connected to rotor side of WRIM to control the o...

This study proposes a parallel connection method for hybrid renewable energy sources connected on the same bus to obtain an optimum load sharing system among them. Although output voltage of the energy sources connected on the bus changes abruptly, the system continuously adjust the output voltage to a pre-defined constant reference value. Power sh...

The use of renewable energy sources are rapidly increasing as alternatives to conventional sources. As Turkey having a great potential of renewable sources, the consciousness of community is a very significant issue for the development in this area. A survey of renewable energy awareness is conducted in this paper; implemented on university student...

In this study, a highly instructive and novel remote laboratory platform using up to date software and hardware units is designed to teach main concepts of Electrical Engineering with the help of web-based simulations and remote accessible experiments in real time. Interactive experimental applications for direct current (DC) motors and several ele...

Data mining is a process of getting out useful information from data stacks. One of the most common application areas is to use classification of algorithms that estimate the future events by past experiences. In this context, in order to predict future events, a data warehouse is created by using the background of students which includes demograph...

In this paper, an experimental application focused on energy quality observation is developed. The required parameters are obtained from the system by the designed electronical measurement cards and then transferred to the computer. As the controller a Data Acquisition card is used and also a user-friendly web interface is prepared for computing an...

In this study, parallel connection of separate voltage sources has been realized using cuk converters. For this aim, output voltages of converters are measured continuously and then fixed to a reference value. The PWM signals which are required to control the converters and to sense the current and voltage signals are generated by an FPGA. Since th...

In this paper, an experimental application focused on energy quality observation is developed and power factor correction for the electrical power systems is simulated. The required parameters are obtained from the system by electronic cards and then transferred to the computer. As the controller a (DAQ) Data acquisition card is used and also a use...

In this study, a step motor training set is designed for educational purposes to resolve the lack of application on electrical machines and control techniques education. Forward and reverse rotation of the motor, application of half step and full step movement and speed control can be performed with designed microprocessor-based circuit and also vi...

In this study, energy monitoring system of a medium scale industrial plant is achieved through a computer interface both in real time and retrospective using recent data. In order to measure the energy, a measurement card is designed to convert the voltage and current signals in suitable levels for a programmable logic controller (PLC). Current and...

In this study, speed control of an induction motor by V/f ratio is presented visually in order to figure out the relation between the frequency and the speed of the motor. By the use of the system, transient and steady state behaviours of the motor under different frequencies can be analysed successfully over the visual user interface. The system c...

This study presents development of the system architecture to perform laboratory experiments over the Internet for electrical engineering education. Design and implementation of four-quadrant speed control experiment for a direct current (DC) motor is given in the article as a sample remote experimental study. The system designed consists of four m...

Nowadays, power electronics systems developed need small size, reliable, high quality and efficient switch mode power supplies. However, switch mode power supplies also require determining the operating parameters accurately for achieving intended energy conversion effectively and faultlessly. In this study, an interactive and object oriented param...

Ab stract-In this study, a novel zero-crossing detector has been designed and implemented that operates as quite steady under the distorted grids due to harmonics. For this aim, a circuit has been designed using UA741, an operational amplifier, which is not affected owing to instant spikes and sags on the signals of current or voltage. Most of the...

In recent years, interest to active power filters has been increased. This paper presents a comparative evaluation for two types of harmonic extraction methods used widely for single phase shunt active power filters which are the p-q theory and the sine multiplying method. These control theories are investigated in detail considering their mathemat...

This article introduces a novel web-based DC motor laboratory, called NeTRe-LAB, to support teaching electrical machines. The NeTRe-LAB includes favorable animations to facilitate understanding characteristics of the DC motor, interactive DC motor models for instructive simulations, and web-based experiments with online monitoring features. To illu...

In this study, an experimental application has been achieved for three phase induction motors including observation and control the motor speed by adjusting the frequency. A frequency converter and a PLC (Programmable Logic Controller) have been used in the system as main hardware units. Experimental operations such as starting and stopping the mot...

In this study, a Simulink simulation is realized for a converter system that is located between fixed-speed wind turbine and grid. The 3-phase output voltage has been modelled as a squirrel cage induction generator output as being the most widely used generator type in wind turbines. The output line voltages of wind turbine has been converted to DC...

This study introduces development of a user-friendly and quite effectual energy monitoring system which has been installed in Electrical Education Department of Gazi University in Turkey and in use since November 2007. The system developed monitors data in real time using a powerful energy analyzer which is capable of measuring many parameters of e...

In this study, real time monitoring and controlling of an elevator prototype based on PLC is developed. The software of PLC has been improved in Simatic Version 4.0 and the main control interface is also developed in Visual Basic as more visual. The system has been applied on a laboratory sized elevator prototype which includes a dc motor, sensors...

In this study, a smart home automation system has been developed to automatically achieve some activities performed frequently in daily life to obtain more comfortable and easier life environment. In the system developed, terminals and other components are controlled and observed via a computer interface using a programmable logic controller (PLC)....

In this paper, a fuzzy logic controller has been developed to obtain a stable current output adjusting the modulation index of a multilevel converter in a variable speed wind turbine system. The variable speed wind turbine system has been modeled containing a squirrel-cage induction generator (SCIG), and SPWM controlled AC-DC-AC converter which is...

This study introduces to usage of an up-to-date software platform named .NET for the Web-based learning models directed to education of a more special area that includes electrical machines courses in where dynamic and interactive simulations are also included. Users can perform several didactic educational activities by means of these dynamic simu...

This study introduces an original e-laboratory platform providing the use of experimental learning method. In this regard, experimental sets remotely accessible in real time via the internet have been developed. Electrical Control Circuits course and its laboratory applications have been dealt as sample studies. For this aim, an elaboratory platfor...

In this study, the speed and torque of a wound rotor induction motor (WRIM) have been controlled by adjusting the rotor resistance using a microcontroller. PI controller has been chosen for the speed control due to its simple structure and higher response time. Realized system has been tested on a 1,5 kW WRIM in a laboratory. Experimental results s...

In this study, internet-controlled heating ventilating and air-conditioning (HVAC) system has been proposed with programmable sleeping time and automatic operation mode, three steps fan speed unit, adjustable fan angle, a remote control device with an LCD and a web based control unit. A low cost microcontroller (MC) to control HVAC system and a PC...

In this study, a microcontroller based DC/DC boost converter has been designed and implemented for solar energy systems. The switching signals required to operate the system are generated by the microcontroller. Similarly, the current and the voltage values at the input terminal of the converter are measured by the microcontroller, and then the pow...

This paper describes the design and implementation of a data acquisition card for the hybrid energy system. Parameters of the solar and the wind sources such as the current, the voltage, the direction of wind, the operation conditions and the position of the solar system can be changed and illustrated on an LCD and displayed on a PC using the card...

This study introduces original system architecture for the Web based remote experimentation applications for e-learning systems. The speed control of a traveling wave ultrasonic motor (USM) is achieved as a remote experimental study over the Internet to illustrate the architecture. For this reason, a microcontroller based digitally controlled drive...

ZET Bu çalışmada, bir mikrodenetleyici yardımıyla rotoru sargılı asenkron motor (RSAM)'un rotor devresi direnci ayarlanarak, motorun tork ve hız kontrolü gerçekleştirilmiştir. Hız denetleyicisi olarak, yapısının basit ve tepki hızının yüksek olmasından dolayı PI denetleyici tercih edilmiştir. Gerçekleştirilen çalışma laboratuar ortamında 1,5 kW güc...

In this study, MATLAB Web Server (MWS), a special toolbox to deploy any MATLAB applications over the Internet easily, based simulation applications are developed and tested. Electrical machines which is an important topic in electrical engineering are dealt with and web based simulation of a direct current motor is developed. Thanks to results obta...

This study introduces a novel web based learning tool for electrical machines education. The tool developed consists of the real time experiments remotely accessible via internet in addition to thereotical presentations with animations and simulations on mathematical models of the electrical machines. The system is based on server/client architectu...

ZET Bu çalışmada, darbe genişlik modülasyonu denetimli IGBT anahtarlama elemanı kullanılarak bir doğru akım motorunun dört bölge hız denetimi gerçekleştirilmiştir. Uygulama çalışmasında PIC 18F4520 mikro denetleyici kullanılmıştır. Dört bölge kontrolünde tam köprü sürücü kullanılarak ölü bant gecikmesi yok edilmiştir. Hazırlanan deney kartı üzerind...

In this study, a digital protection and wye-delta starting relay based on PIC 16F877 microcontroller has been implemented for three-phase induction motors. The relay checks the phase sequence, phase loss and low/over voltage conditions before the motors started with wye-delta method. The relay developed in this study has superior features when comp...

In this study, a computer controlled building security system based on CANModul-592 microcontroller has been designed and implemented. The system includes fire alarm and intrusion detectors. The signals generated by detectors are transmitted to CANModul-592 that processes the signals and then sends to a computer via parallel port for controlling an...