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Acquisition method of adaptive fractional phase-locked loop under grid voltage fault

A grid voltage and acquisition method technology, applied to the phase angle between voltage and current, electrical components, circuit devices, etc., can solve the problem of slow dynamic response speed of the loop filter, and achieve a wide range of parameter selection and filtering effect Good, the effect of increasing the corresponding speed

Active Publication Date: 2017-07-28
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to solve the problem that the phase sequence separation of the existing phase-locked loop cannot work accurately and quickly under various power grid faults, and the dynamic response speed of the loop filter is slow, and provides an automatic Adaptive Fractional Phase Locked Loop

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  • Acquisition method of adaptive fractional phase-locked loop under grid voltage fault
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  • Acquisition method of adaptive fractional phase-locked loop under grid voltage fault

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specific Embodiment approach 1

[0020] Specific implementation mode one: the following combination figure 1 with figure 2 Describe this embodiment, the acquisition method of the adaptive fractional phase-locked loop under the grid voltage fault described in this embodiment, the specific process of this method is:

[0021] Step 1. Establish a mathematical model in the two-phase α, β static coordinate system when the grid voltage fails;

[0022] Step 2, obtaining an adaptive observer according to the mathematical model obtained in step 1;

[0023] Step 3. Realize positive and negative sequence separation in the two-phase phase α, β static coordinate system;

[0024] Step 4, obtaining the angular frequency value of the grid voltage;

[0025] Step 5. Carry out coordinate transformation on the positive sequence component after separating the positive and negative sequences, and pass the fractional order PI in the synchronous d and q coordinate system λ The regulator is phase-locked to obtain the loop filter;...

specific Embodiment approach 2

[0027] Specific implementation mode two: this implementation mode further explains implementation mode one, and the mathematical model under the two-phase α, β static coordinate system when the grid voltage fault is established as described in step 1 is:

[0028]

[0029] Among them, e αβ Indicates the grid voltage in the two-phase stationary coordinate system; are positive and negative sequence components respectively; E + ,E - are the amplitudes of positive and negative sequence components respectively; ω is the fundamental angular velocity of grid voltage; are the initial phases of the positive and negative sequence components, respectively.

specific Embodiment approach 3

[0030] Specific implementation mode 3: This implementation mode further explains the implementation mode 2. The specific process of acquiring the adaptive observer described in step 2 is:

[0031] Set variable:

[0032] Differentiate formula (1) and formula (2) respectively to obtain the dual relational expression:

[0033]

[0034] in,

[0035] Set variables according to formula (2):

[0036] Among them, ω 0 Indicates the approximate value of the fundamental wave;

[0037] Then formula (3) is transformed into:

[0038]

[0039] in,

[0040] Then the adaptive observer is:

[0041]

[0042] in, with respectively e αβ , μ αβ and the observed values ​​of ξ,

[0043] is the observed value of ω; is the observation error; G(·) is the damping part added to the observer,

[0044] Take here Both δ and ρ are positive numbers.

[0045] In this embodiment, formula (5) and formula (6) are made difference, obtain:

[0046]

[0047] in, is the ob...

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Abstract

The invention provides a self-adaption fractional order phase-locked loop obtaining method under the power grid voltage fault, and relates to a self-adaption fractional order phase-locked loop. The method aims to solve the problems that phase sequence separation of an existing phase-locked loop cannot be achieved accurately and quickly under various power grid faults, and the dynamic response speed of a loop filter is low. The self-adaption fractional order phase-locked loop obtaining method under the power grid voltage fault includes the specific steps that mathematical models of a phase alpha and a phase beta under a static coordinate system when the power grid voltage fault occurs are built; a self-adaption observer is obtained; positive and negative sequence separation is achieved; an angular frequency value of the power grid voltage is obtained; the loop filter is obtained; the angular frequency value is transmitted to the loop filter in a feedforward mode, and the self-adaption fractional order phase-locked loop is obtained. The self-adaption fractional order phase-locked loop obtaining method is used for a wind generation set.

Description

technical field [0001] The invention relates to an adaptive fractional phase-locked loop. Background technique [0002] Many current standards require wind turbines to have power grid fault ride-through capability, which requires wind turbines to be able to work normally under a certain degree of voltage dips, voltage imbalances, frequency distortions, and phase mutations. Therefore, how to quickly and accurately detect the positive and negative sequence amplitude and phase information of the grid voltage becomes the key to the grid-connected inverter. [0003] The existing phase sequence separation schemes of PLLs mainly include: 1. Filter method based on synchronous d, q coordinate system; 2. Notch filter method based on synchronous d, q coordinate system; 3. Based on α, β stationary coordinates The T / 4 delay method of the system. However, the phase sequence separation scheme based on the synchronous d and q coordinate system will introduce a low-pass filter, but it will...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/00G01R19/04G01R25/00
CPCH02J3/00H02J2203/20
Inventor 郑雪梅李朋丁丹玫曹瀚楠李秋明冯勇
Owner HARBIN INST OF TECH