Resonance suppression method and system for grid-forming converter system based on sequence impedance remodeling

Abstract

The present disclosure discloses a resonance suppression method and system for a grid-forming converter system based on sequence impedance remodeling. The method comprises: obtaining grid-side voltage, grid-side current and converter-side current small signals after linearization based on a grid-forming converter active and reactive control strategy and a voltage and current dual-closed-loop control principle, and building a sequence impedance model of a grid-forming converter system output impedance based on a virtual synchronous generator; determining conditions for system stability based on the sequence impedance model in combination with a passive theory; and introducing an active damping feedback loop into a voltage control link of a grid-forming converter in combination with the conditions for system stability and remodeling an equivalent output impedance of converter resonance control to reduce a non-passive area of output positive and negative sequence impedances and achieve harmonic resonance suppression of a grid-connected current of the grid-forming converter.

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