Transient stability judgment method and device for follow-up network type converter series-parallel system

By constructing an equivalent model of a hybrid system that includes virtual impedance, and utilizing the Lyapunov energy function and the Lassell invariant set principle, the problems of strong parameter dependence and lack of quantitative criteria in hybrid systems of grid-connected and grid-connected converters are solved. This enables quantitative judgment and parameter tuning of transient stability, thereby improving the transient stability of the system.

CN122136975APending Publication Date: 2026-06-02SHANGHAI UNIVERSITY OF ELECTRIC POWER
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Patent Information

Application Number
CN202610292715.1
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2026-03-11
Publication Date
2026-06-02

AI Technical Summary

Technical Problem

In the existing technology, the transient stability analysis of the hybrid system of grid-connected and grid-connected converters relies on fixed parameters inside the system, which are difficult to adjust flexibly and lack quantitative stability criteria, making the system prone to instability during faults and unable to provide specific parameter boundaries.

Method used

By constructing an equivalent model of a hybrid system that includes virtual impedance, and using the Lyapunov energy function and the Lassell invariant set principle, the critical range of virtual impedance is determined, the electrical coupling relationship between grid-type and grid-connected converters is optimized, and the quantitative judgment of transient stability is achieved.

Benefits of technology

It enables quantitative judgment and parameter tuning of the transient stability of the hybrid system, optimizes the electrical coupling relationship of the system during faults, and improves the transient stability of the system.

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Abstract

The invention relates to the technical field of power electronic converter control, and discloses a method and a device for judging transient stability of a hybrid system of a following and constructing network type converter, and the method comprises the steps: constructing an equivalent model of the hybrid system comprising the following network type converter and the constructing network type converter, and connecting a virtual impedance in a branch of the constructing network type converter in series; constructing a Lyapunov energy function according to the equivalent model, wherein independent variables comprise a power angle and a phase-locked loop frequency of a following network type converter, and a power angle, a frequency and a voltage amplitude of a constructed network type converter; when the derivative of the energy function with respect to time is smaller than or equal to 0, determining the stability domain boundary of the hybrid system by using a Ressel invariant set principle; and calculating the critical value range of the virtual impedance according to the change trend of the stability domain boundary, and determining the target value of the virtual impedance to maintain the transient stability of the hybrid system. According to the method, quantitative judgment and parameter setting of the transient stability of the hybrid system are realized.
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