Hamed Aliakbar - Iran University of Science and Technology,
Mahyar Khosravi - Iran University of Science and Technology,
Ali Asghar Bahrami Hidaji - Islamic Azad University - South Tehran Branch,

Today, the fast development of technologies related to renewable energy resources which has resulted in their cost decrease, allows reducing the use of fossil fuels and consequently, better protection of the environment. Another advantage of these resources is the possibility to employ them in remote areas. In order to integrate these resources, the microgrid concept has been proposed in the past years. The control of microgrids based on the distributed energy resources (DERs) and power electronic interfaces is an important and inevitable subject. In this paper, a system including a PV generator, a wind turbine connected to a doubly-fed induction generator (DFIG) and a wind farm together with power electronic devices and a battery energy storage is formed. Both linear and non-linear loads have been employed in this system. It should be noted that the main grid has been modeled as an infinite bus. The simulation results have been presented for this system. Beside these elements, a subsystem called central controller is also proposed and included in the system. This subsystem controls the whole system performance during load change conditions using a microturbine generator and the battery energy storage. The output power of the other generators available in the system are kept constant by this controller. This controller also improves the power quality and stability of the system. Moreover, a harmonic analysis is done for different voltage and current waveforms of the elements available in the system

Battery, Microgrid, central controller, Microturbine