A control method and device for an energy storage system

Abstract

The invention discloses a control method and device for an energy storage system. The method comprises the steps of calculating an output voltage reference value and a voltage phase angle of the energy storage system according to a VSG (Virtual Synchronous generator); carrying out coordinate conversion on the output voltage reference value, thereby obtaining a voltage component under a two-phase synchronous rotating coordinate system; taking the voltage component as an input voltage for voltage current double loop control, and carrying out the voltage current double loop control to obtain a three-phase voltage reference value; equally dividing the three-phase voltage reference value according to the number of power conversion units of each power conversion link, and superposing each part of the equally divided three-phase voltage reference value and the voltage component obtained through battery balance control, thereby obtaining a voltage reference signal of each power conversion unit. The energy storage system provided by the invention works under a voltage source state both in a grid-connected mode and a grid-disconnected mode, so a control policy does not need to be switched and the voltage and current overshoot problem is avoided. Through utilization of automatic voltage adjustment and frequency adjustment capabilities of the VSG, the energy storage system has a plug and play function and a voltage frequency automatic regulation function.

Description

technical field [0001] The present application relates to the technical field of electronic power conversion, in particular to a control method and device for an energy storage system. Background technique [0002] With the development of technology and the increase of environmental pressure, more and more distributed energy sources appear in production and life. Among them, the output of distributed energy sources such as wind power generation and solar power generation is random, intermittent and volatile, and large-scale Access will bring huge challenges to power grid peak regulation, operation control and power supply quality. Large-capacity energy storage technology can effectively improve the ability of the grid to accept distributed energy, and solve the problem of "intermittent energy generation directly connected to the grid impacting the grid", which will contribute to the faster development of distributed energy and increase the role of distributed energy in the g...

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Problems solved by technology

[0005] This application provides a control method and device for an energy storage system to solve the problems that a large-capacity energy storage system is difficult to seamlessly switch when off-grid and cannot be plugged and played in micro-grid applications

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