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Improved virtual flux linkage orientation-based harmonic detection method

A virtual flux linkage and harmonic detection technology, applied in special data processing applications, instruments, electrical digital data processing, etc., can solve problems such as weak distortion and strain capacity, asymmetric grid voltage, etc., achieve stable frequency and realize frequency self-adaptation , Accurately track the effect of frequency changes

Inactive Publication Date: 2019-08-20
XUZHOU NORMAL UNIVERSITY
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  • Description
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  • Application Information

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Problems solved by technology

[0005] The purpose of the invention is to a kind of can improve traditional i p -i q The disadvantage of the harmonic detection algorithm is that it has weak adaptability to grid-side voltage distortion, and it can accurately lock the phase angle and frequency of the grid to eliminate the traditional i p -i q Harmonic detection algorithm Due to the detection error caused by grid voltage asymmetry, waveform distortion and DC offset component injection, the fundamental positive sequence current obtained by the system basically has no distortion

Method used

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  • Improved virtual flux linkage orientation-based harmonic detection method
  • Improved virtual flux linkage orientation-based harmonic detection method
  • Improved virtual flux linkage orientation-based harmonic detection method

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Embodiment 1

[0036] Such as figure 1 As shown, a harmonic detection method based on improved virtual flux linkage orientation, the grid voltage information passes through a phase-locked loop (Phase-locked Loop, PLL) and a sine-cosine signal generation circuit to obtain a sine-cosine signal in phase with the grid voltage, Calculate the grid phase angle and accurately lock the grid voltage phase. However, when the grid voltage is distorted or unbalanced, the effectiveness of the PLL will be greatly reduced, and there will be large errors in the phase-locked results, which will also affect the i p -i q The accuracy of the assay.

[0037] image 3 shown as figure 2 Bode plot of the third-order generalized integrator shown. It can be seen from the analysis that G 1 (s) can be regarded as a bandpass filter, which allows the signal of a specific frequency band to pass; G 2 (s) has the property of low-pass filtering, which shows a negative gain for high-frequency components, and can suppre...

Embodiment 2

[0044] This embodiment uses MATLAB / Simulink simulation software to build a simulation model and analyze the simulation results. A three-phase uncontrolled rectifier bridge with resistive inductive load is used as the harmonic source. The main parameters of the circuit are: unbalanced resistance R 1 is 50Ω, the load line inductance L 1 0.1mH, the rectifier bridge load resistor R 2 50Ω, L 2 is 0.1mH. As a comparison, the traditional i p -i q Harmonic detection method and virtual flux-linkage based orientation i p -i q The detection method is simulated and analyzed under different working conditions.

[0045] Figure 7 For the obvious unbalance of each phase voltage on the grid side, 3 zero-sequence, 5 negative-sequence and 7 positive-sequence components are injected, and the phase angle waveform obtained by the harmonic detection method is obtained when the DC component is injected into phase A. This method is hardly affected by grid-side voltage distortion and asymmet...

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Abstract

The invention discloses an improved virtual flux linkage orientation-based harmonic detection method. According to the method, a virtual power grid flux linkage is adopted as an improvement link of aphase-locked loop; the extraction of a positive sequence flux linkage is realized by means of a compound third-order generalized integrator and a positive and negative sequence component calculation module; on the basis that the phase angle and frequency of a power grid are accurately locked, the detection errors of a traditional ip-iq harmonic detection algorithm, which are caused by reasons suchas power grid voltage asymmetry, waveform distortion, direct-current offset component injection and even frequency change, are avoided, so that fundamental wave positive sequence current finally obtained by a system is basically free of distortion.

Description

technical field [0001] The invention relates to a harmonic detection method, in particular to a harmonic detection method based on improved virtual flux linkage orientation. Background technique [0002] The development of human society is inseparable from the utilization of energy. Fossil energy is the main energy used by human beings, including coal, oil and natural gas. However, fossil energy is non-renewable, and its storage capacity has declined sharply with human development. In the near future, fossil energy will be completely exhausted. In addition, the use of fossil energy will generate pollution and reduce the quality of the environment. In recent years, in order to cope with the global energy and environmental crisis, countries all over the world are actively developing various types of renewable energy. Solar photovoltaic power generation has been widely used due to its advantages of large storage capacity, wide distribution, clean and environmental protection,...

Claims

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Application Information

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IPC IPC(8): G01R23/16G06F17/50
CPCG01R23/16G06F30/20
Inventor 孟凡婷贾传圣刘振中
Owner XUZHOU NORMAL UNIVERSITY
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