Research on Accurate Frequency Division Control Strategy for Hybrid Energy Storage Considering Line Resistance

For hybrid energy storage systems in DC microgrids, the virtual impedance control composed of virtual capacitance and virtual resistance can decompose the load power into high-frequency and low-frequency components, which are then respectively allocated to supercapacitors and batteries for response. However, considering line resistance in hybrid energy storage, the load current cannot achieve precise frequency division response. In order to solve this issue, the paper proposes an improved virtual impedance control strategy that can eliminate the limitations of the traditional virtual impedance control in scenarios where cable resistance cannot be neglected in DC microgrid systems. By comparing the traditional virtual impedance control and the improved virtual impedance control, the effectiveness of the proposed control strategy is verified.