| CPC H02J 7/0048 (2020.01) [H02J 7/00032 (2020.01); H02J 7/0014 (2013.01); H02J 7/06 (2013.01)] | 20 Claims |

|
1. A grid connection control method of an energy storage apparatus, wherein the energy storage apparatus comprises a plurality of energy storage sub-modules; the energy storage sub-module comprises a power unit and an energy storage unit; the power unit comprises a rectifying circuit and a voltage-sharing capacitor; the energy storage unit and the voltage-sharing capacitor are respectively connected in parallel with an output end of the rectifying circuit; the energy storage unit is capable of being connected to or disconnected from the output end of the rectifying circuit; input ends of all the rectifying circuits are connected in series to form a main energy transmission circuit; the main energy transmission circuit is capable of being connected to or disconnected from a direct-current bus of an electric power system; the method comprising:
in a state in which the main energy transmission circuit is disconnected from the direct-current bus, sequentially controlling the energy storage units of the energy storage sub-modules to be connected to corresponding voltage-sharing capacitors, so as to make the energy storage units pre-charge the corresponding voltage-sharing capacitors; and
controlling the main energy transmission circuit to be connected to the direct-current bus under a condition that the voltage-sharing capacitor of each energy storage sub-module meets a voltage-sharing capacitor pre-charge completion condition.
|