Internal mold based frequency adaptive phase-locked loop modeling method

Abstract

The invention discloses an internal mold based frequency adaptive phase-locked loop modeling method, and relates to the technical field of signal processing. The method comprises the following steps that a synchronous rotating coordinate system phase-locked loop SRF-PLL model is constructed; a frequency adaptive filter IMAF is used, a positive, negative and zero sequence separated calculation module PNZSC extracts a positive sequence fundamental wave voltage of the power system, and a low pass filter module in the SRF-PLL model is replaced; and at the same time, a source decoupling-end normalized phase-locked loop SUN-FLL is used to provide estimated frequency for the frequency adaptive filter IMAF, and finally the IMAF-PLL model is obtained. The method has a good frequency selection effect and high stability, and the phase-locked loop is more robust to resist voltage fluctuation and frequency fluctuation.

Description

technical field [0001] The invention relates to the technical field of signal processing, in particular to an internal model-based frequency adaptive phase-locked loop modeling method. Background technique [0002] During the operation of an independent power system or an independent grid, in addition to voltage distortion, there will also be system frequency fluctuations or offsets caused by load active power fluctuations. The most commonly used phase-locked loop (SRF-PLL) based on synchronous rotating coordinate system (SRF-PLL), can accurately extract the positive sequence component of the voltage, has good dynamic response speed and small error, but the voltage distortion and frequency fluctuation at the same time In the existing environment, because the low-pass filter of SRF-PLL does not have the ability of frequency adaptation, there are contradictions in the selection of bandwidth, and the synchronization effect is poor; the recently proposed double second order gene...

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Problems solved by technology

The most commonly used phase-locked loop (SRF-PLL) based on synchronous rotating coordinate system (SRF-PLL), can accurately extract the positive sequence component of the voltage, has good dynamic response speed and small error, but the voltage distortion and frequency fluctuation at the same time In the existing environment, because the low-pass filter of SRF-PLL does not have the ability of frequency adaptation, there are contradictions in the selection of bandwidth, and the synchronization effect is poor; the recently proposed double second order generalized integral phase locked loop (Double Second Order Generalized Integrator -PLL, DSOGI-PLL), its filter has a good suppression effect on three-phase unbalance and harmonic voltage, and has frequency adaptive characteristics, but it is still affected by frequency fluctuation and voltage amplitude fluctuation. There is a large phase error in the operating environment of frequency fluctuations

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