US 12,328,003 B2
Energy storage system, power conversion system, and method for optimizing primary frequency modulation
Mingxuan Dong, Shanghai (CN); and Kai Xin, Shanghai (CN)
Assigned to Huawei Digital Power Technologies Co., Ltd., Shenzhen (CN)
Filed by HUAWEI DIGITAL POWER TECHNOLOGIES CO., LTD., Shenzhen (CN)
Filed on Nov. 27, 2023, as Appl. No. 18/519,923.
Application 18/519,923 is a continuation of application No. PCT/CN2021/096865, filed on May 28, 2021.
Prior Publication US 2024/0106238 A1, Mar. 28, 2024
Int. Cl. H02J 3/24 (2006.01); H02J 3/32 (2006.01); H02J 3/34 (2006.01); H02J 7/00 (2006.01)
CPC H02J 3/32 (2013.01) [H02J 3/241 (2020.01); H02J 3/34 (2013.01); H02J 7/00041 (2020.01); H02J 7/0048 (2020.01)] 20 Claims
OG exemplary drawing
 
1. An energy storage system, comprising:
a plurality of energy storage batteries, wherein each of the plurality of energy storage batteries is configured to store or release electric energy;
a battery management system separately connected to a power conversion system and each of the plurality of energy storage batteries, and the battery management system is configured to monitor a state of charge (SoC) value, a voltage value, and a current value of each of the plurality of energy storage batteries; and
the power conversion system, wherein the power conversion system is separately connected to each of the plurality of energy storage batteries and a power grid, and the power conversion system is configured to:
obtain the SoC value of each of the plurality of energy storage batteries; and
determine, based on the SoC value of each of the plurality of energy storage batteries, that a target energy storage battery does not meet a target SoC value; and
when a present frequency of the power grid falls within a frequency modulation constant band, control, based on a preset mapping relationship between a SoC value and an active power, the target energy storage battery to be charged or discharged, wherein in the preset mapping relationship, a lower limit value of the SoC value corresponds to a lower limit value of the active power in the frequency modulation constant band, and an upper limit value of the SoC value corresponds to an upper limit value of the active power in the frequency modulation constant band, wherein the SoC value that is of the target energy storage battery and that is monitored by the battery management system reaches the target SoC value, and wherein the frequency modulation constant band is a first preset frequency range of the power grid.