At present, in the distribution network consisting of DC power sources such as PV array, energy storage systems (ESS), data centers and charging, it is an ideal way to select a DC distribution network or a DC microgrid. This paper first establishes a model of DC microgrid consisting of PV array, direct-drive wind turbine generators, ESS and DC load, where PV array and direct drive wind turbines generators operate in MPPT control mode and ESS use improved droop control method. Ensure that the DC microgrid is rapidly entering a new stable point when the load or renewable energy resources (RES) input is constantly changing, so that the microgrid remains stable within a certain range. On the basis of voltage stability, the relationship between the MPPT curve of RES and the sagging characteristics of ESS is studied. The optimal control method of RES and ESS is adopted to appropriately change the operating characteristics of RES and it is no longer mandatory to operate at MPPT. Instead, run near this point to ensure optimal operation of the grid. The simulation results verify the effectiveness of the improved energy storage droop control mode and combined optimal control mode of RES and ESS.