Adaptive-notch-filter-based harmonic wave extraction method

An adaptive notch and harmonic extraction technology, applied in the field of measuring electrical variables, can solve problems such as difficulty in application and measurement errors

Inactive Publication Date: 2015-08-19
ZHEJIANG UNIV
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Problems solved by technology

[0004] There are relatively mature methods for harmonic and reactive current detection in three-phase circuits, such as the three-phase instantaneous reactive power method, etc. However, for single-phase circuits, these methods are difficult to apply
[0005] Therefore, it is necessary to provide a harmonic extraction method based on an adaptive notch filter to solve the measurement problems generated by the original adaptive notch filter (ANF) method when there is a DC offset in the input and when the amplitude changes. error problem

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Embodiment Construction

[0033] The present invention will be described in further detail below in conjunction with the accompanying drawings.

[0034] A harmonic extraction method based on an adaptive notch filter, the steps are as follows:

[0035] 1. Collect the signal to be tested through the sampling device to obtain the input signal ;

[0036] 2. For input signal Processing to obtain the instantaneous value of each harmonic , fundamental frequency , DC offset , and each harmonic amplitude :

[0037] For the input signal by the following set of differential equations Do harmonic extraction:

[0038]

[0039] in: is the input signal containing harmonics; h is the number of harmonics; , , , Both are the quantity to be demanded of the equation; It is an adjustable parameter, which can be set as required; is the calculated fundamental wave amplitude; It is an adjustable parameter, which is used to represent the detection accuracy of the algorithm, and can be set as n...

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Abstract

The invention, which belongs to the technical field of electrical variable measurement, provides an adaptive-notch-filter-based harmonic wave extraction method. The method comprises: a, collecting a to-be-measured signal by a sampling device to obtain an input signal u(t); and b, carrying out harmonic wave extraction on the input signal u(t) so as to obtain each harmonic instantaneous value ./xh, a fundamental frequency omega 1, a direct current deviation A0, and each harmonic amplitude Ah. With the method, a problem of measurement error occurrence when direct current deviation occurs in the input and the amplitude is changed according to the original adaptive notch filter (ANF) method can be solved. Even though the amplitude and frequency of the input signal are changed suddenly and even the direct-current deviation is added, the fundamental frequency, the direct current deviation, and each harmonic instantaneous value and each harmonic amplitude can be extracted in real time with high precision based on the algorithm.

Description

technical field [0001] The invention belongs to the technical field of measuring electric variables, and in particular relates to a harmonic extraction method based on an adaptive notch filter. Background technique [0002] Electricity is an indispensable and important energy source in modern society, but with the development of science and technology, a large number of nonlinear power electronic devices appear in the modern power system, which makes the high-order harmonics in the power grid more and more serious. The direct manifestation of its impact on the power system is the periodic distortion of the current and voltage waveforms. In these current and voltage waveforms, a series of sine wave components (higher harmonic components) with frequencies that are integral multiples of the fundamental frequency appear. Higher harmonic components are called power harmonics. Power harmonics pose a potential threat to the safety, stability and economic operation of the power sys...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R23/165
Inventor 许征杰
Owner ZHEJIANG UNIV
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