In this paper

a DC microgrid (DCMG) integrated with a set of nano-grids (NG) is studied. DCMG exchanges predetermined active and reactive power with the upstream network. DCMG and NGs are coordinately controlled and managed in such a way the exchanged P-Q power with external grid are kept on scheduled level following all events and operating conditions. The proposed control system

in addition to the ability of mutual support between DCMG and NGs

makes NGs support each other in critical situations. On the other hand

in all operating conditions

DCMG not only feeds three-phase loads with time-varying active and reactive power on the grid side but also injects constant active power into the grid. During events

NGs support each other

NGs support DCMG

and DCMG supports NGs. Such control strategies are realized by the proposed control method to increase resilience of the system. For these purposes

all resources and loads in DCMG and NGs are equipped with individual controllers. Then

a central control unit analyzes

monitors

and regularizes performance of individual controllers in DCMG and NGs. Nonlinear simulations show the proposed model can effectively control DCMG and NGs under normal and critical conditions.