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Frequency locking method and device for converting delay based on four-sampling method

A frequency-locking and frequency-locking loop technology, applied in circuit devices, harmonic reduction devices, AC network circuits, etc., can solve problems such as frequency-locking is susceptible to interference, long locking time, and poor harmonic suppression ability

Active Publication Date: 2021-09-10
SUZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] The purpose of the present invention is to provide a frequency-locking method and device based on four-sampling conversion delay, which can solve the problem of long locking time of the entire loop in the frequency-locked loop, frequency-locking that is susceptible to interference when the voltage signal has a DC bias, and The problem of poor harmonic suppression ability

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  • Frequency locking method and device for converting delay based on four-sampling method
  • Frequency locking method and device for converting delay based on four-sampling method
  • Frequency locking method and device for converting delay based on four-sampling method

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Embodiment 1

[0077] refer to figure 1 , the embodiment of the present invention provides a frequency-locking method based on four-sampling conversion delay, comprising the following steps:

[0078] S1: Obtain the initial three-phase grid voltage and convert it into a representation in the αβ two-phase stationary coordinate system;

[0079] S2: Construct a frequency-locked loop model based on the conversion delay of the four-sampling method, and use the frequency-locked loop model to determine the grid frequency estimate and the positive-sequence component and negative-sequence component of the three-phase grid voltage.

[0080] Specifically, such as Figure 1-Figure 3 As shown, the expression of the three-phase voltage in the a, b, c three-phase stationary coordinate system is transformed into the expression in the αβ two-phase stationary coordinate system by using the Clark transformation mathematical model. details as follows:

[0081] Express the three-phase voltage in the power grid...

Embodiment 2

[0141] Based on the same inventive concept, this embodiment provides a frequency-locking device based on four-sampling conversion delay, its problem-solving principle is similar to the above-mentioned frequency-locking method based on four-sampling conversion delay. No longer.

[0142] A frequency-locking device based on four-sampling conversion delay, comprising:

[0143] A coordinate converter for obtaining the initial three-phase grid voltage and converting it to a representation in the αβ two-phase stationary coordinate system;

[0144] The frequency-locked loop is used to construct the frequency-locked loop model based on the conversion delay of the four-sampling method and determine the estimated value of the grid frequency and the positive-sequence component and negative-sequence component of the three-phase grid voltage.

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Abstract

The invention discloses a frequency locking method and device for converting delay based on a four-sampling method. The frequency locking method comprises the following steps of acquiring initial three-phase power grid voltage and converting the initial three-phase power grid voltage into representation under an alpha-beta two-phase static coordinate system, and constructing a frequency-locked loop model based on four-sampling method conversion delay, and determining a power grid frequency estimation value and a positive sequence component and a negative sequence component of three-phase power grid voltage by using the frequency-locked loop model. The problems that the locking time of the whole loop in the frequency-locked loop is long, the frequency locking is easy to interfere under the condition that the voltage signal has direct current bias, and the harmonic suppression capability is poor can be solved.

Description

technical field [0001] The invention relates to the technical field of grid-connected inverters, and in particular to a frequency-locking method and device based on four-sampling conversion delay. Background technique [0002] In today's power production, transmission, distribution, and consumption systems, connecting various power electronic devices to perform flexible and reliable secondary regulation of electric energy is conducive to effectively enhancing the stability of the power system and improving the efficiency of energy use. When distributed power is connected to the large power grid through a grid-connected converter, the control of the grid-connected converter requires a grid synchronization system to accurately estimate the frequency and phase information of the fundamental positive-sequence voltage of the grid. At present, phase-locked loop technology and frequency-locked loop technology are the most widely used in power grid synchronization technology. [00...

Claims

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Application Information

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IPC IPC(8): H02J3/44H02J3/38H02J3/01
CPCH02J3/44H02J3/381H02J3/01H02J2203/20Y02E40/40
Inventor 王浩然樊明迪傅锐王绪郭琳媛杨勇赵龙陈蕴哲
Owner SUZHOU UNIV