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

A fundamental wave positive sequence, voltage extraction technology, applied in the measurement of current/voltage, the phase angle between voltage and current, electrical components and other directions, can solve the problems of slow operation speed, complex algorithm, difficult to achieve, etc., to achieve simple algorithm , Fast and accurate extraction, the effect of occupying less memory

CN104698254BActive Publication Date: 2017-08-22GUANGZHOU INST OF ENERGY CONVERSION - CHINESE ACAD OF SCI
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2017-08-22

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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.
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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...

Examples

Embodiment Construction

[0039] Such as Figure 1-2 As shown, a power grid fundamental wave positive sequence voltage extraction method includes the following steps:

[0040] a. When the power grid voltage is unbalanced, the fundamental wave of the power grid contains the positive sequence voltage of the fundamental wave of the power grid, the negative sequence voltage of the fundamental wave of the power grid, and the zero sequence voltage of the fundamental wave of the power grid, and the three-phase voltage obtained by sampling is e a 、e b 、e c They are:

[0041]

[0042]

[0043]

[0044] In the formula, U + , Indicates the effective value and initial phase angle of the fundamental positive sequence voltage of the power grid, U - , Indicates the effective value and initial phase angle of the fundamental negative sequence voltage of the power grid, U 0 , Represents the effective value and initial phase angle of the fundamental zero-sequence voltage of the power grid, w represent...