Battery Optimization Operation Strategy for the "SOP-Storage-Charger" Devices Based on Adjustable Virtual Impedance

The soft open points-storage-charger (SSC) device integrates flexible interconnection, energy storage, and charging functions, which can mitigate energy fluctuations in the distribution network. However, during its operation, the frequent utilization of energy storage resources leads to high-power charging and discharging of batteries, thereby affecting their lifespan. To address this issue, a battery optimization operation strategy for the SSC device based on adjustable virtual impedance is proposed. Firstly, the functions of flexible interconnection, energy storage, and charging are all equivalently modeled as virtual impedances. The various energy pathways during the energy fluctuation process in the distribution network are analyzed. By adjusting the virtual impedance, the fluctuating energy can be effectively managed. Based on this, considering the operational characteristics of the SSC device, control methods for the adjustable virtual impedance of each part are proposed, and the physical significance and design principles of key parameters are analyzed. Finally, an experimental platform is built based on a hardware-in-the-loop (HIL) system to verify the theoretical results. The research demonstrates that the proposed method can mitigate voltage fluctuations in the distribution network while reducing the magnitude of charging and discharging currents in the energy storage system, thereby improving battery lifespan.