*5.1. Steady State*

This case validates the distributed cooperative control when the DCESs are at a steady state, by comparing the performance of the droop control and consensus control. The simulation results of the primary control and distributed cooperative control of this multiple DCESs are shown in Figures 8 and 9, respectively.

**Figure 8.** Only with the primary control of multiple DCESs: (**a**) DC-bus voltage; (**b**) battery SOC.

In Figure 8, with only the primary control, the CL DC bus voltage is regulated to 119.2 V but deviates from the reference value of 120 V because of the droop gains and power allocation. The SOCs of the four batteries, whose initial value SOC0 are different from each other, are still in difference after the discharging. In Figure 9, the distributed cooperative control is simulated. It can be seen that the CL DC bus voltages between the four DCESs are in consensus and the average value is regulated to the rated value, owing to the secondary voltage control. However, the CL DC bus voltage of the individual DCES may differ from the rated value. Moreover, the SOCs eventually converge toward consensus thanks to the fact that the secondary SOC control forces the batteries with a high SOC to be discharged faster and meanwhile the batteries with a low SOC to be charged faster.

**Figure 9.** Distributed cooperative control of multiple DCESs: (**a**) DC-bus voltage; (**b**) battery SOC.
