Energy storage transformation system and control method thereof

Abstract

The invention provides an energy storage transformation system and a control method thereof, and the method comprises the steps: judging whether an own off-grid side input parameter is greater than an absorbable parameter or not after an energy storage converter in the energy storage transformation system detects that a power grid is abnormal; if yes, for the purpose of controlling power reduction of power generation control equipment arranged on the off-grid side of the energy storage converter, controlling the energy storage converter to stop grid connection, and judging whether off-grid side input parameters meet preset switching conditions or not in real time; when the result is satisfied, controlling itself to switch into an off-grid operation state, and outputting a first preset off-grid voltage frequency; and because grid-connected operation stopping is not equal to off-grid operation, enabling the power generation control equipment to trigger over-frequency protection after detecting the first preset off-grid voltage frequency, so that the energy storage converter can determine the action time sequence of self rapid grid-connected and off-grid switching according to the relation between the off-grid side input parameter and the absorbable parameter when the power grid is abnormal, rapid off-grid power supply can be achieved under the condition that requirements are met, and the problem of overvoltage of the energy storage bus is solved.

Description

technical field [0001] The invention relates to the technical field of control technology, in particular to an energy storage transformation system and a control method thereof. Background technique [0002] At present, in the energy storage retrofit system, taking the parallel operation of the photovoltaic inverter and the energy storage converter as an example, the wiring method is generally as follows: figure 1 Shown: The AC output side of the photovoltaic inverter is connected to the off-grid side of the energy storage converter. [0003] When the power grid is abnormal, the photovoltaic inverter can use the off-grid voltage of the energy storage converter to realize power generation operation; when the load is light and the sunlight is sufficient, the photovoltaic inverter can charge the battery of the energy storage converter; Heavy, the photovoltaic inverter can supply power to the load together with the energy storage converter to improve the energy utilization rate...

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Problems solved by technology

[0005] In this regard, this application provides an energy storage retrofit system and its control method to solve the problem that the existing energy storage retrofit system needs to be switched to off-grid operation when an abnormality occurs on the grid side during grid-connected operation. In the fully charged state or without battery access, the energy storage converter cannot absorb the power of the photovoltaic inverter, resulting in the problem of busbar overvoltage

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