Transient energy function analysis method considering inverter current saturation

Abstract

The invention provides a transient energy function analysis method considering inverter current saturation. Based on an inverter virtual synchronous generator control strategy, by establishing a virtual synchronous generator rotor movement equation and considering the inverter current saturation factor, a transient energy function is established with the first integral method; approximation is conducted on non-integrable terms relevant to path in the transient energy function with the linear path method, then the critical energy value is obtained with the BCU method, and critical clearing time is obtained. According to the transient energy function analysis method considering virtual rotational inertia and inverter current saturation, the stability of an electric system containing a virtual synchronous generator can be evaluated quantitatively; the transient energy function is established considering the inverter saturation factor and is closer to reality, the problem that system instability can be caused when a traditional online evaluation method is adopted due to conservative property is solved, and the method is an important supplement to time-domain simulation methods.

Description

technical field [0001] The invention designs a power system stability and control technology, in particular a transient energy function analysis method considering inverter current saturation. Background technique [0002] At present, with the increasing penetration rate of distributed power and the use of digital circuit control for power electronic devices connected to distributed power to the grid, the transient response speed is fast and there is almost no inertia. When DG accounts for a certain proportion, Small disturbances in the power grid can cause security and stability problems. In this context, scholars at home and abroad have proposed virtual synchronous generator technology, which realizes the friendly access of distributed power sources by controlling the inverter to simulate the operating principle of synchronous generators. [0003] Research on virtual synchronous generators domestic and foreign scholars focus on the grid-connected inverter to simulate the ...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a transient energy function analysis method considering inverter current saturation, which solves the problem that the critical cut-off time obtained by the traditional transient energy function analysis method considering the virtual moment of inertia inverter is too conservative, and when the system There is a major problem of system instability due to the long resection time during online evaluation

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