Energy storage system and black start method thereof

Abstract

The invention provides an energy storage system and a black start method thereof. The energy storage system can comprise a plurality of energy storage modules, a plurality of direct current switches, at least two energy storage converters and a plurality of alternating current switches, wherein the plurality of energy storage modules are connected with the input ends of the at least two energy storage converters through the plurality of direct current switches, and the output ends of the at least two energy storage converters are connected in parallel to a parallel operation point through a plurality of alternating current switches; when each energy storage converter in the at least two energy storage converters detects a black-start starting instruction, the direct current switch and the alternating current switch corresponding to each energy storage converter are switched on so as to be connected to a parallel operation point in parallel; and each energy storage converter is also used for carrying out soft start at a voltage phase zero-crossing position of the parallel operation point, so that the output alternating voltage reaches the rated voltage to realize black start of the energy storage system. In the energy storage system and the black start method thereof, synchronous soft start can be carried out at the voltage phase zero-crossing position of the parallel operation point, and synchronous startup of all the energy storage converters is ensured, so that the black start time is shortened, the ring current is reduced, and the applicability is high.

Description

technical field [0001] The present application relates to the technical field of battery energy storage, and in particular to an energy storage system and a black start method thereof. Background technique [0002] When the micro-grid or isolated grid system is black-started, the system will be completely powered off, and the system will be in a "black" state. At this time, by starting the generator set with self-starting capability in the system (such as energy storage converter (power conditioning system, PCS)), to drive the generator set without self-starting capability, so as to realize the black start of the whole system (such as on-load start and no-load start). When the system is started on load, a single energy storage converter cannot start all the loads at the rated voltage, so at least two energy storage converters are required to be connected in parallel and start at the same time to meet the system's on-load start-up requirements. [0003] The inventors of the ...

AI Technical Summary

Problems solved by technology

However, the existing technology cannot control the simultaneous start-up of each energy storage converter, and cannot guarantee that the output voltage of each energy storage converter increases to the rated voltage at the same time, resulting in a large circulating current between each energy storage converter. And the black start time is too long

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