Phase-locked loop and phase locking method

A phase-locked loop and phase-locked technology, applied in the direction of electrical components, automatic power control, etc., can solve the problem that phase-locking cannot be achieved, and achieve the effect of smooth frequency self-adaptation, fast frequency self-adaptation, and accurate calculation

Inactive Publication Date: 2016-06-15
CENT SOUTH UNIV
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Problems solved by technology

[0005] The present invention provides a phase-locked loop and a phase-locked method, the purpose of which is to overcome the existing in the prior art biquad generalized PLL in the case of frequency fluctuations, imbalances and harmonics in the grid voltage, which cannot be realized phase lock problem

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  • Phase-locked loop and phase locking method
  • Phase-locked loop and phase locking method

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Embodiment Construction

[0064] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0065] A phase-locked loop adopts a biquad generalized integrator phase-locked module, and the biquad generalized integrator phase-locked module includes a Clark coordinate system transformation module, a QSG module, a PNSC module and an SRF-PLL module;

[0066] Among them, the QSG module is a quadrature signal generator, the PNSC module is a positive and negative sequence calculator, and the SRF-PLL module is a synchronous rotating coordinate system PLL module;

[0067] Also includes an HE module and an AFRC module connected to a biquad generalized integrator phase-locked module;

[0068] The HE module is a harmonic elimination module, and the AFRC module is a reference angular frequency calculation module;

[0069] The output terminal of the HE module is connected with the output terminal of the PI module in the SRF-PLL.

[0070] At the same time, t...

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Abstract

The invention discloses a phase-locked loop and a phase locking method. The phase-locked loop comprises a Clark transformation module, a QSG module, a PNSC module, a synchronous rotating coordinate system PLL module, an HE module and an AFRC module. The novel PLL can accurately operate under the situations of unbalanced voltage and serious voltage harmonic and frequency variation. The provided QSG and AFRC can accurately detect the positive-sequence power grid voltage sequence, the HE can well eliminate harmonic waves under the condition of serious power grid pollution, the AFRC make the frequency self-adapt quickly and be smooth, and the PLL can be achieved in the case that the power grid voltage has frequency fluctuation, imbalance and harmonic waves at the same time; the digital implementation of the improved digital PLL is performed through a method using a Tustin predeformation and increment algorithm to discretize, and the accuracy of the harmonic broadband of the power grid voltage can be ensured.

Description

technical field [0001] The invention belongs to the field of power grid control, in particular to a phase-locked loop and a phase-locked method. Background technique [0002] With the rapid development of power electronic devices, they play an increasingly important role in power systems. In power transmission, power conversion and power quality improvement, various types of power electronic equipment are used, such as flexible AC transmission system (FACTS), uninterruptible power supply (UPS), active power filter (APF) and so on. One of the most important aspects of controlling these grid-connected power converters is proper synchronization with the grid voltage, which requires the use of a phase-locked loop (PLL). [0003] Under normal grid voltage conditions, the synchronization of grid-connected inverters can be achieved by using the traditional PLL algorithm in the synchronous rotating coordinate system or the stationary coordinate system. If the grid voltage fails, t...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03L7/085
CPCH03L7/085
Inventor 于晶荣王越王家明于佳琪徐勇粟梅
Owner CENT SOUTH UNIV
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