A method for extracting fundamental positive-sequence voltage of power grid and phase-locking method

Abstract

A power grid fundamental wave positive sequence voltage extraction method and a phase-locking method. The power grid fundamental wave positive sequence voltage extraction method uses a first-order inertial link to process the detected power grid fundamental wave voltage with a delay of 60°, and has a filtering effect at the same time. It can filter the high-order harmonics in the power grid, and then perform phasor operation on the processed power grid fundamental wave to obtain the positive sequence voltage of the power grid fundamental wave, so it can quickly and accurately extract the positive sequence voltage of the power grid fundamental wave. The algorithm is simple and takes up memory. less, can meet the requirements of digital control; the phase-locking method adds the above-mentioned power grid fundamental wave positive sequence voltage extraction link into the phase locked loop, and sends the power grid fundamental wave positive sequence voltage into d, q transformation to obtain the power grid fundamental wave positive sequence voltage phase , the phase-locking method extracts the fundamental positive-sequence voltage of the power grid before the Park transformation, does not need to use a low-pass filter, does not generate second harmonics, and thus does not affect the dynamic response speed of the system, ensuring accurate phase-locking.

Description

technical field [0001] The invention mainly relates to the technical field of extracting the fundamental positive-sequence voltage of the power grid and phase-locking in a state where the voltage of the power grid is distorted, and in particular relates to a method for extracting the fundamental positive-sequence voltage of the power grid and a phase-locking method. Background technique [0002] Now, various power electronic devices have been widely used in power systems, such as power active filters, dynamic reactive power compensation devices and grid-connected inverters, etc. Fast and accurate detection of grid amplitude and phase information is an important condition for ensuring the normal operation of these devices, ensuring power quality and equipment safety. [0003] In order to ensure the normal operation of various power electronic devices and ensure the power quality, the current zero-crossing comparison method is used to track the grid voltage phase, and the zero...

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Problems solved by technology

[0006] Patent No. 2013106023801 "Fundamental Positive Sequence Voltage Extraction and Phase-Locking Method" discloses a fundamental wave positive-sequence voltage extraction and phase-locking method. Using this method to extract the fundamental positive-sequence voltage of the power grid is to use the Clerk transform first, and the The three-phase voltage is transformed into a two-phase coordinate system of α and β. After two coordinate transformations, the fundamental positive sequence voltage of the power grid is obtained. However, using this method to extract the positive sequence voltage of the fundamental wave of the power grid requires a delay of 60° and a lead of 60°. and a leading 90° operation, the algorithm is complicated, and it is difficult to realize in the control system of the actual power electronic equipment

[0007] Patent No. 201200551382 "A Method for Detection of Power Grid Fundamental Positive Sequence Voltage Phase" can also realize the extraction of power grid fundamental positive sequence voltage, but a low-pass filter is used, and inverse triangulation is required in the operation Function operation, the operation speed is slow when implemented on the DSP platform

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