Voltage control of a hybrid ac/dc microgrid in stand-alone operation mode

The stability of dc and ac bus voltage is of the most important issues in all microgrids including ac, dc or ac/dc hybrid microgrids. In this paper, a hybrid ac/dc microgrid is proposed to reduce processes of multiple reverse conversions in an ac or dc microgrid and to facilitate the connection of various renewable ac and dc sources and loads to power system. Also, all control schemes used among all converters will be developed in order to improve the voltage stability of hybrid microgrid. To give robustness to improve the dynamic voltage stability of the microgrid, a voltage stabilizer is proposed and applied to the doubly fed induction generator (DFIG) installed in ac part. Results are achieved considering the uncertainty of the generators and loads existed in microgrid verifying the robustness of the controllers to restore and stabilize quickly the voltage of both ac and dc grids.