Decentralized Autonomous Energy Management Strategy for Multi-Paralleled Hybrid Energy Storage Systems in the DC Microgrid with Mismatched Line Impedance

In this paper, a decentralized P-V{2} droop-based energy management strategy for the hybrid energy storage systems (HESSs), including multiple batteries/supercapacitors (SCs), in the DC microgrid is proposed. By using the output voltage of the SC converter as the unified feedback voltage in each HESS, the impacts of non-negligible and mismatched line impedance on the power allocation performance and bus voltage tracking are eliminated. Compared with the I-V droop-based method, the adopted P-V{2} droop technique improves the stability of the HESS, especially considering the constant power loads (CPLs). In addition, the state-of-charge (SoC) recovery is considered for the SCs to prolong the service life of the HESSs. Finally, the experiment and hardware-in-the-loop (HIL) simulations have been carried out for the studied system to verify the effectiveness of the proposed control strategy.