Pseudo passive power grid impendence recognition system and method based on Goertzel algorithm

A technology of power grid impedance and identification method, applied in the measurement of resistance/reactance/impedance, impedance measurement, measurement of electrical variables, etc., can solve the problems of low quality of incoming current and burden on digital controllers, and achieve low system disturbance and high precision. , the effect of high efficiency
CN108445295AActive Publication Date: 2018-08-24武汉高仕达电气有限公司
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
武汉高仕达电气有限公司
Publication Date
2018-08-24

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Abstract

The invention relates to a pseudo passive power grid impendence recognition system and a method based on a Goertzel algorithm. The system comprises a grid-connected inverter, a sampling module, a control module and a PWM driving module, wherein the grid-connected inverter outputs a current set value into a power grid, the sampling module can sample lineside voltage and current through a voltage sensor and a current sensor, the control module can utilize the Goertzel algorithm to extract harmonic component signals of the sampled lineside voltage and current; finally, the harmonic component signals are utilized to calculate the power grid impendence. The pseudo passive detection method comprises the steps of monitoring power grid impendence and injecting harmonic wave into a power grid to measure power grid impendence when larger change happens. The method has the advantages of higher accuracy and smaller system disturbance. The Goertzel algorithm can effectively reduce a controller calculation amount and storage space and further reduces code complexity. In the occasions when only several frequency points need to be analyzed, the Goertzel algorithm has a higher efficiency than FFT.
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Description

Technical field

[0001] The invention relates to the field of distributed power generation systems, in particular to a quasi-passive grid impedance identification system and method based on the Goertzel algorithm. Background technique

[0002] Distributed power generation system fully integrates and utilizes scattered resources to produce and supply energy on-site according to user needs. It has multiple functions and can meet multiple goals of small and medium-sized power conversion and utilization systems.

[0003] The performance of the power system is closely related to the grid impedance, and the grid impedance changes with time and the operation status of the grid. Therefore, the accurate measurement of the grid impedance is the key technology to realize the high-performance adaptive control of the power system in the weak grid situation.

[0004] Conventional grid impedance measurement methods are:

[0005] The passive detection method uses the existing harmonic voltage, harmoni...

Claims

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