US 12,348,042 B2
Photovoltaic energy storage system and control method thereof
Jixing Qiu, Shanghai (CN); Shen Chen, Shanghai (CN); and Feidong Xu, Shanghai (CN)
Assigned to Delta Electronics (Shanghai) Co., Ltd., Shanghai (CN)
Filed by Delta Electronics (Shanghai) Co., Ltd., Shanghai (CN)
Filed on Jan. 6, 2022, as Appl. No. 17/570,166.
Claims priority of application No. 202110086850.8 (CN), filed on Jan. 22, 2021.
Prior Publication US 2022/0239107 A1, Jul. 28, 2022
Int. Cl. H02J 3/38 (2006.01); H02J 3/32 (2006.01); H02J 7/00 (2006.01)
CPC H02J 3/381 (2013.01) [H02J 3/32 (2013.01); H02J 7/00712 (2020.01); H02J 2300/24 (2020.01)] 21 Claims
OG exemplary drawing
 
1. A control method for a photovoltaic energy storage system, the photovoltaic energy storage system comprising an energy storage unit, a photovoltaic array assembly, an inverter and a rapid shutdown switch, the inverter being electrically coupled to the energy storage unit and the photovoltaic array assembly, the rapid shutdown switch is electrically coupled to the inverter, a power grid and a load, the inverter comprising a first terminal, a second terminal and a common terminal, a voltage between the first terminal and the common terminal being a first voltage, a voltage between the second terminal and the common terminal being a second voltage, a voltage between the first terminal and the second terminal being a third voltage, the control method comprising steps of:
(S1) detecting at least two voltages of the first voltage, the second voltage and the third voltage;
(S2) determining whether the rapid shutdown switch is turned off according to the at least two detected voltages and a reference value; and
(S3) when it is determined that the rapid shutdown switch is turned off, cutting off a connection between the inverter and the energy storage unit and a connection between the inverter and the photovoltaic array assembly,
wherein the reference value contains a first threshold value, and the first voltage, the second voltage and the third voltage are obtained after the step S1 is completed, wherein the step S2 comprises sub-steps of:
obtaining a first ratio after an absolute value of a difference between the first voltage and the second voltage is divided by the third voltage;
comparing the first ratio with the first threshold value; and
when the first ratio is greater than the first threshold value, confirming that the rapid shutdown switch is turned off.