US 12,334,732 B2
Off-grid start method and system for new energy power generation system
Xing Li, Hefei (CN); Houlai Geng, Hefei (CN); Qun Zheng, Hefei (CN); Menglin Cao, Hefei (CN); and Zhifei Zhang, Anhui (CN)
Assigned to Sungrow Power Supply Co., Ltd., Hefei (CN)
Appl. No. 18/273,006
Filed by Sungrow Power Supply Co., Ltd., Hefei (CN)
PCT Filed Nov. 8, 2021, PCT No. PCT/CN2021/129245
§ 371(c)(1), (2) Date Jul. 18, 2023,
PCT Pub. No. WO2022/166289, PCT Pub. Date Aug. 11, 2022.
Claims priority of application No. 202110150471.0 (CN), filed on Feb. 3, 2021.
Prior Publication US 2024/0088656 A1, Mar. 14, 2024
Int. Cl. H02J 3/00 (2006.01); H02J 3/18 (2006.01); H02J 3/38 (2006.01); H02J 3/46 (2006.01)
CPC H02J 3/007 (2020.01) [H02J 3/18 (2013.01); H02J 3/388 (2020.01); H02J 3/46 (2013.01); H02J 2203/10 (2020.01)] 9 Claims
OG exemplary drawing
 
1. A method for starting a new energy power generation system in an off-grid mode, wherein the new energy power generation system comprises one master unit and N−1 slave units, N is a positive integer greater than 1, the master unit is configured with N sequentially increasing predetermined voltages, and an N-th predetermined voltage is a rated predetermined voltage, wherein the method comprises:
controlling, by the master unit on detecting that a load voltage is less than a predetermined value, an output voltage of the master unit to be gradually increased based on the sequentially increasing predetermined voltages until a voltage stabilization condition is met, wherein the voltage stabilization condition comprises a condition in which the master unit has an overcurrent risk or a condition in which the output voltage of the master unit reaches the rated predetermined voltage;
determining, by each of the slave units after detecting that the load voltage is stabilized, a target predetermined voltage of the master unit meeting the voltage stabilization condition based on the stabilized load voltage;
starting a target slave unit with the target predetermined voltage as a predetermined voltage, and connecting the target slave unit to the master unit in parallel, wherein an identification of the target slave unit matches an arrangement number of the target predetermined voltage in the predetermined voltages; and
controlling, by the master unit after determining that the target slave unit is successfully connected to the master unit in parallel by detecting an output current of the master unit, the output voltage of the master unit to be gradually increased based on the sequentially increasing predetermined voltages until the voltage stabilization condition is met, until all the slave units are connected to the master unit in parallel and operate;
wherein the controlling, by the master unit on detecting that a load voltage is less than a predetermined value, an output voltage of the master unit to be gradually increased based on the sequentially increasing predetermined voltages until a voltage stabilization condition is met comprises:
controlling, by the master unit on detecting that the load voltage is less than the predetermined value, the output voltage of the master unit to be gradually increased based on the predetermined voltages;
determining, when a predetermined voltage of the master unit is increased to an i-th predetermined voltage and i is less than N, whether the master unit has an overcurrent risk based on the output current of the master unit, wherein i is a positive integer, 1≤i≤N, N represents a total number of the master unit and the slave units, and the N-th predetermined voltage is the rated predetermined voltage;
in a case that the master unit has the overcurrent risk, determining that the voltage stabilization condition is met; and
in a case the master unit does not have the overcurrent risk, updating the predetermined voltage of the master unit to be an (i+1)th predetermined voltage, and controlling the output voltage of the master unit to be gradually increased based on the predetermined voltages.