  Restricting bus voltage deviation is crucial for normal operation of
multi-bus DC microgrids, yet it has received insufficient attention due to the
conflict between two main control objectives in DC microgrids, i.e., voltage
regulation and current sharing. By revealing a necessary and sufficient
condition for achieving these two objectives, this paper proposes a compromised
distributed control algorithm, which regulates the voltage deviation of all
buses by relaxing the accuracy of current sharing. Moreover, for a class of DC
Microgrids consisting of both critical nodes and ordinary nodes, this paper
proposes a distributed control algorithm that restricts the voltage deviation
of critical nodes and simultaneously keeps the current sharing of ordinary
nodes. This algorithm also works under plug-and-play settings. Simulations
illustrate our theory.
