A novel communication-less control method for PV-ESS DC microgrids

Abstract This paper presents a novel communication-less control method for PV-ESS DC microgrids. First, the ESS closest to the critical load is selected as the master unit, and output voltage is set at the nominal voltage. This unit injects an AC signal into the DC bus, and the frequency of the signal is determined by the unit's SOC and current. Then, other ESSs (called slave units) regulate their output currents according to the received AC signal frequency and local SOC without participating in the bus voltage regulation. In addition, thelogic signal is introduced to determine whether the PV module operates at maximum power point Tracking (MPPT) or droop control mode based on the received frequency. Simulation results demonstrate that the proposed control method achieves superior performance compared to traditional droop control. The method ensures higher load sharing accuracy, lower voltage deviation, and SOCs equalization in the DC microgrid system relying no communication link.