An adaptive digital phase-locked loop and phase-locked method

Abstract

The present invention provides an adaptive digital phase-locked loop, including a phase detector, a PI regulator, and a conversion unit. The adaptive digital phase-locked loop also includes a sampling unit, a frequency multiplier, and an integral conversion unit, wherein the sampling The unit is used to sample the three-phase grid voltage at the sampling frequency generated by the frequency multiplier; the integral transformation unit is used to generate a phase-locked output phase according to the phase-locked output frequency; the frequency multiplier is used to A sampling frequency is generated according to the phase-locked output frequency, and the sampling frequency is N times the phase-locked output frequency, where N is a positive integer. The invention also provides a corresponding phase locking method. The self-adaptive digital phase-locked loop of the present invention can overcome the problem of large phase-locking error in the phase-locked loop based on synchronous rotation coordinate transformation, can automatically adapt to the frequency change of the power grid, realize fast tracking of the phase of the power grid, and improve the phase-locking precision.

Description

technical field [0001] The invention relates to the technical field of phase locking, and more specifically relates to an adaptive digital phase locking loop and a phase locking method, which are applied to grid-connected converters. Background technique [0002] The basic function of the phase-locked loop is to track and lock the phase of the AC signal, and provide information about the frequency and amplitude of the signal when necessary. In the control of the grid-connected converter, it is necessary to dynamically obtain the phase information of the grid voltage. Therefore, the performance of the phase-locked loop directly affects the performance of the grid-connected control of the converter. [0003] At present, in order to effectively improve the phase-locked accuracy and fast response of the phase-locked loop in the project, digital closed-loop phase-locked technology is generally used. The main solutions are: phase-locked loop based on zero-crossing detection, phase...

AI Technical Summary

Problems solved by technology

[0006] The technical problem to be solved by the present invention is to provide an adaptive digital phase-locked loop and a phase-locking method in view of the fact that the existing phase-locked loop technology cannot accurately find the phase zero point of the power grid under the condition that the frequency range of the power grid is large

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