Seamless switching control system and seamless switching control strategy based on indirect current control and droop control

Abstract

The invention discloses a seamless switching control system and a seamless switching control strategy based on indirect current control and droop control. A unique control structure is adopted, and a three-ring control structure constituted by a capacitance current internal ring, a capacitance voltage ring, and a grid-connected current ring is adopted, and at the same time, a unique phase-locked loop module, a phase-angle selection module, and a droop control module are provided. Current source control of an inverter switched to voltage source control based on the droop control during switching from grid-connection operation to isolated island operation is realized, and the load voltage quality of the process of the switching from the grid-connection operation to the isolated island operation is improved.

Description

technical field [0001] The invention belongs to the research field of grid-connected inverter control, and in particular relates to a seamless switching control system and strategy based on indirect current control and droop control. Background technique [0002] With the deepening of the environmental and energy crisis, new energy power generation has received more and more attention and application, and the grid-connected inverter is an indispensable interface device for the new energy power generation system to transmit electric energy to the grid. The performance of the inverter will have an important impact on the stability of the power generation system and the grid. [0003] When the grid is normal, the grid-connected inverter should be able to run in parallel with the grid, and supply power to the load together with the grid. When the grid fails, the distributed generation unit should immediately disconnect from the grid and supply power to the load independently, fo...

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Problems solved by technology

[0004] The purpose of the present invention is to overcome the above-mentioned problem that the main inverter fails and the whole microgrid system cannot work in the improved indirect current control, and to provide a seamless switching control system and strategy based on indirect current control and droop control, which can realize inverter The seamless switching between the grid-connected mode and the island mode improves the quality of the load voltage during the switching process, and in the island mode, the micro-grid system can operate in a multi-master and multi-slave structure, which improves the reliability of the system

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