Automatic Superimposed Droop Frequency Control Scheme for DC Microgrids

This paper proposes a control strategy to improve the superimposed droop frequency control scheme in DC microgrids. Conventional droop-based schemes for DC microgrids control suffer from issues such as inaccurate power sharing among the sources, voltage control with insufficient quality, and adverse effect of the line resistance on the droop characteristic. To overcome these challenges, the superimposed droop frequency method has been introduced. However, the stable operation in terms of the load variations and improper voltage quality are still the challenges with this prior-art method due to the injected AC voltages. In this paper, a method is proposed to solve the stability problem and alleviate the overall voltage quality in the superimposed droop frequency scheme. The performance of the proposed method is verified by different simulation studies in MATLAB/SIMULINK environment.