Micro-grid system and control method therefor

Abstract

The invention relates to a micro-grid system, which comprises a storage battery, an energy storage converter, a monitoring circuit and a controllable switch. When the micro-grid system is in a grid-connected mode, the energy storage converter outputs a constant power under the control of an inner current loop unit; an outer voltage loop unit does not participate in the control in the grid-connected mode, but is still in an operating state; and the outer voltage loop unit estimates a given current loop signal in advance when the micro-grid system is switched into an island mode from the grid-connected mode according to four input signals of the outer voltage loop unit. When the micro-grid system is switched into the island mode from the grid-connected mode, the outer voltage loop unit is put into operation, and the inner current loop unit controls output voltage and frequency of the energy storage converter to be constant according to the given current loop signal which is estimated in advance and output by the outer voltage loop unit. According to the micro-grid system, the outer voltage loop unit controls the output given current loop signals to be the same before and after the mode is switched, so that seamless switching of the grid-connected mode or the island mode can be achieved. The invention further relates to a control method for the micro-grid system.

Description

technical field [0001] The invention relates to the technical field of power supply, in particular to a microgrid system and a control method thereof. Background technique [0002] A microgrid system is a small distribution subnetwork that includes distributed power generation devices, energy storage converters and loads, and has certain self-regulation and control capabilities. It can operate both in grid-connected mode and in island mode in the event of a grid failure. Microgrid technology has promoted the development of renewable energy utilization and distributed power generation, and has attracted the attention of countries all over the world. [0003] In the micro-grid system, the energy storage converter is the core of the entire micro-grid system, which stores energy in the grid-connected mode, and acts as the main power supply of the micro-grid system in the island mode, providing voltage and frequency for the entire micro-grid system support. At present, the cor...

AI Technical Summary

Problems solved by technology

At present, the core problem of the microgrid system is how to reduce the switching impact caused by switching the microgrid system from the grid-connected mode to the island mode so as to achieve seamless switching. However, there are still technical difficulties in achieving seamless switching in traditional technologies. It may even lead to instability of the microgrid system

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