Distributed Cooperative Secondary Control for Critical Bus Voltage Regulation

Abstract

Centralized secondary control has been utilized to regulate the voltage in island DC microgrids following droop control. Distributed Secondary control is employed because of the vulnerability to single point of failure in centralized control. In order to restore the crucial bus voltage to its nominal value and to ensure that the current distribution between the converters is acceptable, this paper suggests secondary distributed control that is consensus-based. Only the linked converters contribute to the regulation, and the critical bus controls the voltage adjustment. The undirected graph makes it simple to implement distributed energy resource cooperation through communication linkages. The consensus technique enables the system to accomplish both global and local goals while resolving problems that couldn't be handled separately. The voltage and current neighborhood tracing errors are produced as two adjustment terms (δv and δi. By combining these two elements, the nominal voltage is restored, and the current is properly distributed among the energy sources. All buses are connected to the leader to improve the consistency of voltage restoration and enhance the performance of the controllers associated with the proposed controllers in the literature. The voltage can be efficiently restored if all converters fail except one. To verify the effective operation of the suggested control method, a Medium Voltage DC Microgrid with five buses is tested using MATLAB-Simulink. It is made certain that the distributed secondary cooperative control can maintain voltage stability and enhance the distribution of current between converters.