Energy conversion device of micro-grid

Abstract

The invention relates to an energy conversion device of a micro-grid, and belongs to the technical field of grid energy control, the device comprises an AC / DC power converter, a non-isolated DC / DC power converter and an isolated DC / DC power converter, the AC / DC power converter adopts a T-type three-level inverter circuit structure, and an AC side is connected with an AC grid. A direct current side is connected with the non-isolated DC / DC power converter and the isolated DC / DC power converter through a direct current bus, so that the conversion of a working mode in a bidirectional transition process between a grid-connected state and an off-grid state can be completed; a main circuit of the non-isolated DC / DC power converter adopts a three-level bidirectional conversion circuit, a first port of the non-isolated DC / DC power converter is connected with a DC bus, a second port of the non-isolated DC / DC power converter is connected with an energy storage battery, and the non-isolated DC / DC power converter is used for realizing charging, discharging and voltage stabilizing effects; the isolated DC / DC power converter comprises a pre-stage structure and a post-stage structure which are respectively corresponding to the BUCK-BOOST circuit and the bidirectional AC / DC power resonant converter and is used for realizing charging and discharging of an electric vehicle load. According to the invention, flexible conversion of operation modes of the micro-grid can be realized.

Description

technical field [0001] The invention belongs to the technical field of grid energy control, and in particular relates to an energy conversion device for a micro grid. Background technique [0002] Most of the power sources in the microgrid are micro power sources and small units (less than 100kW) with power electronic interfaces, including micro gas turbines, fuel cells, photovoltaic cells, and energy storage units such as supercapacitors, flywheels, and batteries. These devices are installed on the user side and have the characteristics of low cost, low voltage, and low pollution. However, in the existing microgrid, the grid connection between the microgrid and the large power grid (AC grid) is generally realized through the bidirectional AC / DC. , due to the improper cooperation between the device structure itself and the control strategy, the efficiency of the conversion function of the device is low during operation. Contents of the invention [0003] The object of the...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide an energy conversion device for a micro-grid, which is used to solve the problem of low efficiency of the conversion function of the AC / DC device of the existing micro-grid

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