Series adaptive stabilizer (SAS) for use between grid-connected inverter and weak grid

Abstract

A series adaptive stabilizer (SAS) for use between a grid-connected inverter and a weak grid is disclosed. The SAS solves the problem of instability between the grid-connected inverter (GCI) and the weak grid in a mode of remodeling the impedance of the grid. Different from a traditional stabilizing method, the SAS does not need to know the information about the GCI, so that the SAS is regarded asa black box stabilizing module. The SAS, the GCI and a grid impedor are connected in series, and the SAS only consumes very low power, is higher in efficiency, and is better in economical efficiency.The SAS is realized through a very simple adaptive current controller without any additional phase-locked loop (PLL), and is easy to realize in practical application. In addition, the SAS can be automatically matched with different GCIs, and good adaptability and robustness are achieved.

Description

Technical field [0001] The invention belongs to the technical field of distributed power generation and microgrid, and specifically relates to a series adaptive stabilizer (SAS) used between a grid-connected inverter and a weak grid. Background technique [0002] Distributed power generation is of great significance for efficient use of renewable energy, improvement of energy structure, and response to global climate change. At the same time, the technology has the advantages of flexible installation location, high energy efficiency, and low power transmission line loss, so it has attracted wide attention from countries around the world and has been widely used in northern European countries. In practical applications, distributed generator sets often provide energy to the grid through grid-connected inverters (GCI), in order to achieve the goal of high autonomy and modularity, and at the same time have the advantages of scalability and maintainability. In this process, GCI is u...

AI Technical Summary

Problems solved by technology

[0004] However, all the above existing methods for improving stability focus on how to reshape the GCI impedance, in other words, GCI internal information is indispensable for the successful application of the above methods

However, this requirement actually hinders the modular development of power electronic systems.

For example, if the GCI is changed, the controller needs to redesign the original stabilization method again based on the new information from the new GCI, which obviously increases the R&D cycle and time cost

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