This study proposes a novel combined primary and secondary control approach for direct current microgrids

specifically in islanded mode. In primary control

this approach establishes an appropriate load power sharing between the distributed energy resources based on their rated power. Simultaneously

it considers the load voltage deviation and provides satisfactory voltage regulation in the secondary control loop. The proposed primary control is based on an efficient droop mechanism that only deploys the local variable measurements

so as to overcome the side effects caused by communication delays. In the case of secondary control

two different methods are devised. In the first

low bandwidth communication links are used to establish the minimum required data transfer between the converters. The effect of communication delay is further explored. The second method excludes any communication link and only uses local variables. Accordingly

a self-sufficient control loop is devised without any communication requirement. The proposed control notions are investigated in MATLAB/Simulink platform to highlight system performance. The results demonstrate that both proposed approaches can effectively compensate for the voltage deviation due to the primary control task. Detailed comparisons of the two methods are also provided.