This single-phase energy storage inverter is a highly flexible and efficient core device for energy storage systems, meeting diverse energy needs across scenarios. It supports both grid-tied and off-grid AC coupling functions: when grid-connected, excess solar power can be fed into the grid; in off-grid mode, it delivers stable power supply. The AC coupling design enables easy upgrading of existing systems without modifying original wiring.It allows three-phase configuration and multi-inverter parallel operation, effortlessly expanding power output to meet the demands of residential, small and medium-sized commercial and industrial users. The parallel system maintains strong stability with efficient, interference-free operation.