Microgrid Voltage and Frequency Control Using Droop Control Based on Master/Slave Method

The concepts of a MicroGrid (MG) and distributed generation (DG) are two subjects that have been presented in the areas of electrical distribution systems. The MG is a cluster of various types of DGs working together to transfer a confident, economical, and environmental power. The MG can operate in two independent conditions: connected or islanding modes. Voltage and frequency control of MG is one of the most significant aspects of its stability. Most DG technologies that can be installed in the MG are not suitable for direct connection to the MG due to their power generation characteristics. Therefore, the installation of these units in the MG, using electronic power interfaces is necessary. Hence, the main concern in MG operation is to control power electronic converters. In this paper, droop control based on Master/Slave method was used in the coordinated control structure for voltage and frequency stability. In this method, when the upstream network was disconnected, MG could operate stably in islanding mode then, the voltage and frequency references were provided to other DGs by Master unit. In order to analyze the method proposed, a hybrid microgrid was considered and simulated in DigSILENT Power Factory. The results have shown that the method proposed ensures the performance of MG at emergency conditions such as islanding MG and MG’s voltage and frequency remained at acceptable level.