CN-122001366-A - Three-phase-locked loop control method and device

CN122001366ACN 122001366 ACN122001366 ACN 122001366ACN-122001366-A

Abstract

The invention belongs to the technical field of power system synchronization, and particularly relates to a three-phase-locked loop control method and device. The method comprises the steps of obtaining a q-axis power grid voltage sampling value of a three-phase power grid voltage sampling value under a two-phase rotation coordinate system, inputting the q-axis power grid voltage sampling value into a complex coefficient filtering sliding mode observer, extracting alternating frequency multiplication disturbance caused by distorted power grid voltage to obtain a q-axis voltage estimated value, a direct current estimated value in the alternating frequency multiplication disturbance and a total alternating current estimated value in the alternating frequency multiplication disturbance, wherein the complex coefficient filtering sliding mode observer is obtained based on complex filtering terms of parallel complex coefficient filters in the sliding mode observer, and calculating a phase angle estimated value of a three-phase-locked loop after feedback compensation based on the q-axis voltage estimated value, the direct current estimated value in the alternating frequency multiplication disturbance, the total alternating current estimated value in the alternating frequency multiplication disturbance and the power grid phase voltage amplitude. The control efficiency and accuracy of the phase-locked loop are improved, and the phase-locked loop has good stability and robustness.

Inventors

Guan Rixin
ZOU MIN
ZUO GUANGJIE
LI XIANG
SUN MAOXIANG
WU JIAN
CHENG YUAN
XU TAOTAO
SHI LIANG
CHEN HUIHUI
SHEN XUYANG
SUN TONG

Assignees

华能太仓发电有限责任公司
河南许继电力电子有限公司

Dates

Publication Date: 20260508
Application Date: 20241108

Claims (10)

1. A method of controlling a three-phase locked loop, comprising: acquiring a q-axis power grid voltage sampling value of a three-phase power grid voltage sampling value under a two-phase rotation coordinate system; Inputting a q-axis power grid voltage sampling value into a complex coefficient filtering sliding-mode observer, extracting alternating current frequency multiplication disturbance caused by distorted power grid voltage, and obtaining a q-axis voltage estimated value, a direct current estimated value in the alternating current frequency multiplication disturbance and a total alternating current estimated value in the alternating current frequency multiplication disturbance; And calculating the phase angle estimation value of the feedback-compensated three-phase-locked loop based on the q-axis voltage estimation value, the direct current estimation value in the alternating current frequency multiplication disturbance, the total alternating current estimation value in the alternating current frequency multiplication disturbance and the grid phase voltage amplitude.
2. The method of claim 1, wherein the complex coefficient filtered sliding mode observer has an estimated formula: sig(e 1 ) r ＝|e 1 | r sign(e 1 ) Wherein, the Is the first derivative of the q-axis voltage estimate, u q is the angular frequency estimate, k 1 is the first gain factor, k 2 is the second gain factor, e 1 is the difference between the q-axis grid voltage sample value and the q-axis voltage estimate, The method is characterized in that the method is used for estimating the first derivative of an alternating current frequency multiplication disturbance estimation value, s is a differential operator, r is a gain coefficient of a sliding mode function, b 0 is-1/V m ,V m is a power grid phase voltage amplitude value, and G CCF (s) is a complex filtering term.
3. The method according to claim 2, wherein the calculation formula used in calculating the phase angle estimation value of the feedback-compensated three-phase locked loop is: Wherein, the Is the phase angle estimation value of the three-phase-locked loop, kp is the gain coefficient, As the q-axis voltage estimate value, For a given q-axis voltage reference value, Is the total AC quantity estimated value in the AC frequency multiplication disturbance, Is the DC quantity estimated value in the AC frequency multiplication disturbance.
4. A method according to claim 2 or 3, wherein the difference between the q-axis grid voltage sampled value and the q-axis voltage estimated value is calculated based on the following formula: Wherein e 2 is the difference between the actual value and the estimated value of the alternating current frequency multiplication disturbance, Is the first derivative of the actual value of the ac frequency multiplication disturbance, As the first derivative of e 1 , Is the first derivative of e 2 .
5. The method of claim 1, wherein the complex filter term is a transfer function of a complex coefficient filter.
6. A three-phase-locked loop control device comprises a processor and is characterized in that the processor is used for acquiring a q-axis power grid voltage sampling value of a three-phase power grid voltage sampling value under a two-phase rotation coordinate system, inputting the q-axis power grid voltage sampling value into a complex coefficient filtering sliding mode observer, extracting alternating frequency multiplication disturbance caused by distorted power grid voltage to obtain a q-axis voltage estimated value, a direct current estimated value in the alternating frequency multiplication disturbance and a total alternating current estimated value in the alternating frequency multiplication disturbance, wherein the complex coefficient filtering sliding mode observer is obtained based on complex filtering items of a complex coefficient filter connected in parallel in the sliding mode observer, and calculating a phase angle estimated value of a three-phase-locked loop after feedback compensation based on the q-axis voltage estimated value, the direct current estimated value in the alternating frequency multiplication disturbance, the total alternating current estimated value in the alternating frequency multiplication disturbance and the power grid phase voltage amplitude.
7. The three-phase locked loop control apparatus of claim 6 wherein the complex coefficient filtered sliding mode observer has an estimated formula: sig(e 1 ) r ＝|e 1 | r sign(e 1 ) Wherein, the Is the first derivative of the q-axis voltage estimate, u q is the angular frequency estimate, k 1 is the first gain factor, k 2 is the second gain factor, e 1 is the difference between the q-axis grid voltage sample value and the q-axis voltage estimate, The method is characterized in that the method is used for estimating the first derivative of an alternating current frequency multiplication disturbance estimation value, s is a differential operator, r is a gain coefficient of a sliding mode function, b 0 is-1/V m ,V m is a power grid phase voltage amplitude value, and G CCF (s) is a complex filtering term.
8. The apparatus according to claim 7, wherein the calculation formula used in calculating the phase angle estimation value of the feedback-compensated three-phase locked loop is: Wherein, the Is the phase angle estimation value of the three-phase-locked loop, kp is the gain coefficient, As the q-axis voltage estimate value, For a given q-axis voltage reference value, Is the total AC quantity estimated value in the AC frequency multiplication disturbance, Is the DC quantity estimated value in the AC frequency multiplication disturbance.
9. The three-phase locked loop control apparatus according to claim 7 or 8, wherein the difference between the q-axis grid voltage sampling value and the q-axis voltage estimation value is calculated based on the following formula: Wherein e 2 is the difference between the actual value and the estimated value of the alternating current frequency multiplication disturbance, Is the first derivative of the actual value of the ac frequency multiplication disturbance, As the first derivative of e 1 , Is the first derivative of e 2 .
10. The three-phase locked loop control apparatus of claim 6 wherein the complex filter term is a transfer function of a complex coefficient filter.

Description

Three-phase-locked loop control method and device Technical Field The invention belongs to the technical field of power system synchronization, and particularly relates to a three-phase-locked loop control method and device. Background The phase-locked loop is used as a synchronous device and is generally used for a grid-connected scene of a new energy power electronic converter. However, with the development of a power system, a large amount of nonlinear power electronic equipment is connected into the distributed power generation system, so that a power grid contains rapidly-changing sinusoidal disturbance, which affects the operation of the grid-connected converter and the phase locking of the phase-locked loop. The phase-locked loop of the pre-filtering structure can separate the frequency-doubled sinusoidal disturbance in the power grid, so that the phase-locked loop is widely applied to a scheme of filtering power grid harmonic waves by the phase-locked loop. However, the phase-locked loop controller and the pre-filtering structure need to be designed in two parts, and the traditional phase-locked loop controller usually adopts PI control, and the control parameters are greatly influenced by the operation working conditions, so that the problem of insufficient robustness exists, and certain limitation exists in practical application. In order to solve this problem, b.l. guo et al propose an Extended State Observer (ESO) in a generalized integral form, which can effectively estimate the frequency multiplication disturbance in the power grid, and use the ladc (linear active disturbance rejection controller) as a controller of the phase-locked loop to improve the stability of the system, effectively reduce the influence of the distorted power grid on the phase-locked loop, but the method can only effectively extract the disturbance of a fixed frequency, and when the disturbance frequency of the power grid deviates, a complex frequency adaptive algorithm is required to correct, so that the complexity of the control algorithm is increased, the control speed is slow, and the robustness is to be further improved. Disclosure of Invention The invention aims to provide a three-phase-locked loop control method and device, which are used for solving the problems of slower control rate and lower robustness of the existing phase-locked loop control technology. The invention provides a three-phase-locked loop control method for solving the technical problems, which comprises the following steps: acquiring a q-axis power grid voltage sampling value of a three-phase power grid voltage sampling value under a two-phase rotation coordinate system; Inputting a q-axis power grid voltage sampling value into a complex coefficient filtering sliding-mode observer, extracting alternating current frequency multiplication disturbance caused by distorted power grid voltage, and obtaining a q-axis voltage estimated value, a direct current estimated value in the alternating current frequency multiplication disturbance and a total alternating current estimated value in the alternating current frequency multiplication disturbance; And calculating the phase angle estimation value of the feedback-compensated three-phase-locked loop based on the q-axis voltage estimation value, the direct current estimation value in the alternating current frequency multiplication disturbance, the total alternating current estimation value in the alternating current frequency multiplication disturbance and the grid phase voltage amplitude. Further, the complex coefficient filtering sliding mode observer has an estimation formula: sig(e1)r＝|e1|r sign(e1) Wherein, the Is the first derivative of the q-axis voltage estimate, u q is the angular frequency estimate, k 1 is the first gain factor, k 2 is the second gain factor, e 1 is the difference between the q-axis grid voltage sample value and the q-axis voltage estimate,The method is characterized in that the method is used for estimating the first derivative of an alternating current frequency multiplication disturbance estimation value, s is a differential operator, r is a gain coefficient of a sliding mode function, b 0 is-1/V m,Vm is a power grid phase voltage amplitude value, and G CCF(s) is a complex filtering term. Further, a calculation formula used when calculating the phase angle estimated value of the feedback-compensated three-phase-locked loop is: Wherein, the Is the phase angle estimation value of the three-phase-locked loop, kp is the gain coefficient,As the q-axis voltage estimate value,For a given q-axis voltage reference value,Is the total AC quantity estimated value in the AC frequency multiplication disturbance,Is the DC quantity estimated value in the AC frequency multiplication disturbance. Further, the difference between the q-axis power grid voltage sampling value and the q-axis voltage estimated value is calculated based on the following formula: Wherein e 2 is the difference betwe