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Power grid impedance detection method based on LCL filter damping

A grid impedance and detection method technology, applied in the direction of measuring resistance/reactance/impedance, instruments, measuring devices, etc., can solve the problems of high requirements for system control methods and low accuracy of grid impedance methods, and achieve low cost and reduced The effect of overall cost and high efficiency

Pending Publication Date: 2021-10-08
NORTHWESTERN POLYTECHNICAL UNIV
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  • Abstract
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Problems solved by technology

[0005] To sum up, the commonly used grid impedance method has problems such as low accuracy and high requirements for the system control method.

Method used

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  • Power grid impedance detection method based on LCL filter damping
  • Power grid impedance detection method based on LCL filter damping
  • Power grid impedance detection method based on LCL filter damping

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Embodiment Construction

[0029] In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0030] A grid impedance detection method based on LCL filter damping, comprising steps:

[0031] Step 1. By cascading an all-pass filter to the system, using its ability to reshape the phase of the system can give the system the maximum magnitude margin to keep it stable. By using the Bode diagram of the cascaded all-pass filter in the system under different grid impedances, the all-pass filter that maximiz...

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Abstract

The invention relates to a power grid impedance detection method based on LCL filter damping, and belongs to the power grid impedance detection technology. On the basis that an all-pass filter is used for remodeling a system phase to keep stable, a pole of the all-pass filter is reconfigured to excite system resonance, an inter-harmonic algorithm is adopted to detect a current harmonic frequency during resonance, and the frequency is matched with a system 0dB ride-through frequency under different power grid impedances, so that the detection of a power grid impedance value can be realized. The method has the advantages of being high in pertinence, low in cost, high in efficiency and capable of detecting with the higher impedance resolution, and can be used for detecting the impedance of the power grid to monitor the system state.

Description

technical field [0001] The invention relates to a grid impedance detection technology, in particular to a grid impedance detection method based on an LCL filter damping method. Background technique [0002] At present, there are a large number of literatures at home and abroad that have carried out related research on grid impedance detection. According to the different disturbance modes of grid impedance detection methods, grid impedance detection methods can be classified into active detection methods and passive detection methods. [0003] The grid impedance passive measurement method does not need to inject disturbance signals into the system, but only needs to use the inherent parameter information of the system or the excitation of natural load changes to estimate the grid impedance. The grid impedance active measurement method uses the controller of the inverter itself to generate a disturbance, and actively applies the disturbance to the grid, and then collects the ...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R27/02
CPCG01R27/02
Inventor 姚文利王琪张晓斌
Owner NORTHWESTERN POLYTECHNICAL UNIV