The novel droop control strategy for low voltage microgrid without matching line impedance

In view of the independent operation of the AC low-voltage microgrid, differences can be existed in the state of charge (SOC) of parallel batteries because of the unmatched line impedance, which leads to the over-discharge of energy storage batteries and reduce the energy storage unit life. Therefore, an improved droop control strategy is proposed to consider the energy storage system with unmatched line impedance. Firstly, the dynamic virtual impedance is used to eliminate the influence of the line impedance. At the same time, the SOC index is reduced by the e-index droop, which reduces the impact of the error convergence process on the system. Finally, the control strategy is simulated by Matlab/Simulink, and the correctness and validity of the proposed method are verified.