Ibrahim Sefa

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Interest of renewable energy sources increases with the increasing world power demand and decreasing of fossil energy sources. Many of the new energy sources like the PV, the fuel cell or the wind, produces direct voltage so it is needed a suitable direct current to alternating current inverter to connect them to an alternating current load or the utility(More)
In this study, a single stage, three-phase, three-level neutral point clamped inverter is designed for grid connected renewable energy systems. The proposed voltage source inverter is operated in current controlled mode and a PI current controller is used for the production of switching pattern. Also the proposed inverter is operated in parallel with public(More)
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(More)
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 as an(More)
In this study, a grid interactive inverter which is capable of importing electrical energy, generated from renewable energy sources such as wind, solar and fuel cells, to the grid line is designed and simulated with MATLAB/Simulink. A line frequency transformer and LCL filter is used at the output of the grid interactive inverter that is designed as voltage(More)
In order to obtain uninterrupted power in many critical applications such as control, protection, and communication; high current capacity battery groups are used as a replacement energy source. Charging the battery groups is made by DC/DC converters which are fed over power factor corrected rectifiers in a single or three-phase network according to their(More)
Controlled/uncontrolled rectifiers draw harmonic reach currents from the grid. Harmonic components of the line current affect the grid and other equipment around the point of common coupling. Therefore, so the grid current harmonic distortion levels must be kept at desired level. Multi-pulse rectifiers are commonly used in high power rectifier systems to(More)
In this study, a MATLAB based simulator is designed which can be used for education in power quality and harmonics. The designed simulator is user-interactive and also can be used in undergraduate and graduate laboratory studies. The harmonic components that are entered by the user are visualized graphically. Furthermore, power quality indices such as total(More)