جستجوی مقالات مرتبط با کلیدواژه « عملکرد جزیره ای » در نشریات گروه « برق »

Recently, researchers are increasingly paying attention to the continuous use of renewable systems (such as fuel cells, wind, or solar) due to increased energy consumption, energy supply, and prevention of environmental damage. Photovoltaic power generation (PV) systems are one of the most important low-cost ways among new energy sources. In this paper, a photovoltaic (PV) system is used as the main power generator, and also PEMFC is used as energy storage equipment. The advantages of the proposed system include environmental compatibility, reduction of system noise, and low cost. The proposed control strategy also ensures the system stability in various situations of connection of distributed generation sources, such as photovoltaic system to the grid and non-linear load, which brings the island mode of operation. In addition, a battery with a fuel cell is used to store energy, which has a control system similar to the control of the distributed generation system and does not need to change the control mode of the system when changing the mode from an island.

Microgrid technology makes possible coordination and effective use of different energy resources for supplying loads. In order to have synchronous operation between inverter resources during the occurrence of islanding condition, the use of droop controller structure would be beneficial. In this paper, the conventional droop controller is modified to divide proportional power between resources and cause accurate voltage setting in output resources. By providing a model for connected inverter to the nonlinear load, a harmonic droop controller has been designed. By droop controller related to each harmonic, the harmonic voltages are calculated and add to the reference voltage. Therefore the quality of the output voltage is improved. Then the inverter voltage control loop would be modified with resistance impedance in the presence of non-linear loads, so that, in combination with harmonic droop controller, THD of output voltage considerably reduced. Simulation results show the ability of suggested method in reduction of harmonic voltages in inverters parallel operation.

In this paper a control scheme for grid-connected operation mode and the island state of distributed generation is presented. In normal conditions, every inverter DG system in micro-grids to supply a Preset power, normally operate in a constant current control mode. When micro-grids removed from the network, DG inverter of each system must recognize the island and change position to voltage control mode. In this situation micro-grids supply the fixed voltage to local load. In this paper, a synchronization algorithm is provided for reconnection to the network. The results of the simulation DG, network controllers, and the islanding is provided in MATLAB Simulink.

Constant current and constant voltage- frequency (V-f) control strategies are important control strategies of DG interface that considered in islanding system and connected to network modes in this paper. Constant current control strategy is suitable in connected to network mode; because DG voltage and frequency are equal to voltage and frequency of network. Constant voltage-frequency (V-f) control strategy is suitable in islanding system mode. To evidence of above subject، different scenarios simulated in PSCAD/EMTDC software. These scenarios analyzed different control strategies to distinguish islanding and not to distinguish it.