A method for implementing a phase-locked loop

Abstract

The invention discloses a method for realizing a phase-locked loop. The method of the invention adopts recursive iteration to calculate the weight coefficient of each voltage component by introducing the step size factor of the fundamental wave and each harmonic adaptive filtering link; The per unit value of the component weight coefficient is frequency corrected through the proportional integral control link, and then based on the output signal of the frequency correction link, the output angle of the phase locked loop is obtained after phase correction by the integral link, and is fed back to the adaptive filter Algorithmic, used to reconstruct the fundamental wave and each harmonic, so as to realize the phase-locked loop of the entire double closed-loop adjustment. The method of the present invention can be realized by software programming, and has strong anti-interference; by adopting closed-loop control, the stability is high, the tracking speed is fast, and the low-pass filter link of the traditional phase-locked loop is avoided, and it is not affected by the harmonics and harmonics of the system voltage. Instantaneous drop and other disturbances can accurately and quickly track the fundamental frequency and phase information of the system voltage.

Description

technical field [0001] The invention belongs to the technical field of signal processing, and relates to a method for realizing a software phase-locked loop, in particular to a method for realizing a single-phase software phase-locked loop based on adaptive filtering of affine projection harmonic order. Background technique [0002] Since power electronic devices such as active filters, rectifiers, static var compensators, and photovoltaic grid-connected devices are often used in occasions with poor power quality, there are many situations such as system voltage distortion and instantaneous drop, and these power electronic devices All control systems require accurate and real-time system voltage fundamental frequency and phase information. Therefore, the fundamental frequency and phase tracking system with stable operation and quick response is an important part of the control system. At present, analog phase-locked loop and digital phase-locked loop technology are commonly ...

AI Technical Summary

Problems solved by technology

Its shortcoming is that the phase tracking dynamic response of this algorithm is very slow, and its tracking accuracy and dynamic response speed are affected by the cut-off frequency of the low-pass filter. In the case of system voltage distortion, the fundamental frequency and frequency of the system voltage cannot be accurately obtained. Phase information, and it is difficult to apply to occasions requiring fast response speed

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