Impedance modeling and stability analysis method for voltage-control virtual synchronous generator

Abstract

The invention discloses an impedance modeling and stability analysis method for a voltage-control virtual synchronous generator. The influence of a virtual synchronous generator active controller is considered in order to provide a voltage-control virtual synchronous generator broadband small-signal modeling method based on a sequence impedance model, overcoming the difficulties in voltage-controlvirtual synchronous generator small-signal impedance modeling. On the basis of an established broadband small-signal sequence impedance model, a grid impedance model and Nyquist stability criterion,the influences of grid impedance and the number of voltage-control virtual synchronous generator grid-connected units upon system stability are analyzed. The results show that in any case of high gridimpedance and the large number of the virtual synchronous generator grid-connected units, a virtual synchronous generator grid-connected system can stably run. The models and method are provided forthe small disturbance stability analysis in the scenes, such as voltage-control virtual synchronous generators connected to a grid, and new energy stations; the popularization and application of the voltage-control virtual synchronous generators are benefited.

Description

technical field [0001] The invention relates to the field of renewable energy power generation systems, in particular to a small-signal sequence impedance modeling and stability analysis method for a voltage-controlled virtual synchronous generator. Background technique [0002] With the shortage of fossil energy and the aggravation of environmental pollution, new energy power generation has developed rapidly. A large amount of new energy power generation is distributed in remote areas such as the Gobi, mountains, and islands, making the connection between it and the main grid weak, and the power grid presents the characteristics of high inductance and weak power grid. Traditional new energy grid-connected inverters often adopt a current closed-loop control strategy based on the voltage phase of the grid-connected point, and its external characteristics are current sources. When traditional grid-connected inverters are connected to weak grids, they are prone to interactive ...

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Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide a method for impedance modeling and stability analysis of a voltage-controlled virtual synchronous generator to solve the problem that the voltage-controlled virtual synchronous generator is small when the influence of the active power controller is considered. The Dilemma of Signal Impedance Modeling

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