A multi-band phase-locking method and system based on cross-coupling

Abstract

The invention discloses a multi-band phase locking method and a multi-band phase locking system based on cross coupling. According to the method and the system, a plurality of phase-locked filtering units are adopted for respectively detecting a plurality of frequency components in the electric network voltage, for each phase-locked filtering unit, each frequency component obtained after the filtering processing of other phase-locked filtering unit are fed forward to the input of a phase-locked loop for counteracting the interference on the phase locking and the filtering of the phase-locked filtering units caused by other frequency components in the electric network voltage signals. Because the crossed forward feed effect inhibits the interference of other frequency components, the detection precision of each phase-locked filtering unit on the phase of the corresponding frequency component in the electric network voltage signals is improved, and meanwhile, the phase-locked loop band width in the phase-locked filtering unit can be properly improved, so the response speed of the phase detection of the phase-locked filtering unit is accelerated. The method has the advantages that the phase of positive and negative sequence fundamental wave and harmonic wave components in the electric network voltage can be fast and accurately extracted when the electric network voltage is asymmetrical and generates distortion, in addition, the reliable electric network voltage phase reference can be provided for the control of a grid-connected inverter.

Description

technical field [0001] The invention relates to the technical field of grid-connected operation and control of power electronic converters, and more specifically, to a cross-coupling-based multi-band phase-locking method and system. Background technique [0002] Power electronic converters are widely used in new energy power generation systems and high-voltage direct current transmission systems. The large-scale development of new energy power generation has put forward higher requirements for the grid friendliness of new energy power generation. Under the conditions of grid failure and distortion, the converter needs to maintain grid-connected operation and meet certain active power and reactive power output requirements. HVDC transmission systems need to maintain high reliability in various operating environments such as grid faults and distortions. The control of the converter is based on the grid voltage orientation, and fast and accurate detection of the grid voltage ...

AI Technical Summary

Problems solved by technology

[0006] Aiming at the defects of the prior art, the present invention provides a multi-band phase-locking method based on cross-coupling, which aims to solve the problem that the existing phase-locked loop cannot quickly and accurately extract the phase information of the grid voltage under the condition of unbalanced and distorted grid voltage

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