Microgrid on-grid to off-grid switching control system and control method thereof

Abstract

The invention relates to the field of distributed power generation and microgrids and discloses a microgrid on-grid to off-grid switching control system. The system comprises an energy-storage bidirectional converter, an on-grid switch and a controller; one side of the on-grid switch is connected with the output end of a main power source; the other side of the on-grid switch is connected with the output end of the energy-storage bidirectional converter; the output end of the energy-storage bidirectional converter is connected with a controller; if the controller receives a connection command, the controller adjusts main grid side voltage and microgrid side voltage of the on-grid switch in the same period; after the on-grid switch is closed, the energy-storage bidirectional converter converts from a voltage source mode to a current source mode and keeps current power unchanged; after on-grid time reaches set delay time, the energy-storage bidirectional converter outputs active power and reactive power. The invention further discloses a control method based on the system. By the use of the system, the problem that switching of the running mode of a microgrid causes disturbance to a load and a grid is solved, and seamless off-grid to on-grid switching is achieved.

Description

technical field [0001] The invention relates to the field of microgrids, in particular to a control system and method for switching microgrids from off-grid to grid-connected. Background technique [0002] Compared with conventional centralized power supply stations, distributed power generation has the following advantages: no or little transmission and distribution loss; no need to build substations and distribution stations, avoiding or delaying the increase in transmission and distribution costs; low civil engineering and installation costs; Independent, users can control by themselves, there will be no large-scale power supply accidents, and the reliability of power supply is high; remote control and monitoring of regional power quality and performance can be carried out; environmental protection pressure can be greatly reduced. [0003] With the rapid development of distributed power generation, microgrid is proposed as a new type of power distribution solution, which ...

AI Technical Summary

Problems solved by technology

However, in the existing technology, when the microgrid switches between off-grid and grid-connected operating modes, short-term power outages may occur, and the reliability of power supply is poor.

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