An exCHB_ESS System Battery-Side Fundamental Frequency and Doubled Frequency Ripple Power Suppression Method

The circuit structure of the capacity-expanding high-voltage direct-connected energy storage system (exCHB-ESS) is suitable for large-scale energy storage applications, but the nature of the half-bridge module in the laminated module determines that there are fundamental and doubled-frequency pulsating power during the energy exchange between the battery pack and the grid, which affects the thermal stability and lifetime of the battery pack. In order to suppress the low-frequency pulsating power on the battery side of the expanded high-voltage direct-hanging energy storage system, this paper proposes to insert a composite bi-directional lift-voltage converter between the double-layer battery side and the ratio converter. The power pulsation on the battery side is buffered by controlling the voltage ripple of the intermediate DC capacitor. The simulation and experimental results verify the correctness of the theoretical analysis.