CN-122000901-A - New energy flexible direct current interconnection system oscillation suppression method and device

Abstract

The application provides a new energy flexible direct current interconnection system oscillation suppression method and device. The method can restrain oscillation of the new energy flexible direct current interconnection system according to fundamental wave modulation voltage of the energy storage converter under the three-phase static coordinate system and oscillation restraining voltage of the energy storage converter under the three-phase static coordinate system, reduces difficulty of oscillation restraining, improves practicality of the restraining method, and effectively restrains the oscillation. According to the application, on the basis of not changing the structure of the flexible direct current interconnection system, oscillation suppression is realized, so that the oscillation suppression effect is improved, the running performance of the new energy station and the flexible direct current transmission system is not influenced, the problems of equipment damage or off-grid of the new energy unit and the like are avoided, and the running stability and reliability of the flexible direct current interconnection system are improved.

Inventors

• ZHOU XIAO
• DU ZHENYU
• YANG YUEXI
• SUN YANYING
• BAI YU
• SHU ZHAN

Assignees

• 中国电力科学研究院有限公司
• 国网江西省电力有限公司电力科学研究院
• 国家电网有限公司

Dates

Publication Date

20260508

Application Date

20251216

Claims (20)

1. 1. The new energy flexible direct current interconnection system oscillation suppression method is characterized by comprising the following steps of: Controlling the actual value of the output current of the energy storage converter according to the active power reference value and the reactive power reference value of the energy storage converter to obtain the fundamental wave modulation voltage of the energy storage converter under a three-phase static coordinate system; Calculating oscillation suppression voltage of the energy storage converter under a three-phase static coordinate system according to the three-phase voltage actual value of the new energy station grid-connected point and the output current actual value of the energy storage converter; And suppressing oscillation generated by the new energy flexible direct current interconnection system according to the fundamental wave modulation voltage of the energy storage converter under the three-phase static coordinate system and the oscillation suppression voltage of the energy storage converter under the three-phase static coordinate system.
2. 2. The oscillation suppression method according to claim 1, wherein the controlling the actual value of the output current of the energy storage converter according to the active power reference value and the reactive power reference value of the energy storage converter to obtain the fundamental modulation voltage of the energy storage converter in the three-phase stationary coordinate system comprises: Performing phase-locked loop control on the actual value of the three-phase voltage of the new energy station grid connection point to obtain the synchronous phase of the power grid connected with the new energy flexible direct current interconnection system; Outputting a modulation voltage of the energy storage converter under a two-phase rotation coordinate system according to the synchronous phase of the power grid, the active power reference value of the energy storage converter, the reactive power reference value of the energy storage converter and the output current actual value of the energy storage converter; and performing inverse Pake transformation on the modulation voltage of the energy storage converter under the two-phase rotating coordinate system according to the synchronous phase of the power grid to obtain the fundamental wave modulation voltage of the energy storage converter under the three-phase static coordinate system.
3. 3. The oscillation suppression method according to claim 2, wherein the outputting the modulation voltage of the energy storage converter in the two-phase rotation coordinate system according to the synchronization phase of the power grid, the active power reference value of the energy storage converter, the reactive power reference value of the energy storage converter, and the output current actual value of the energy storage converter includes: performing park transformation on the actual value of the output current of the energy storage converter to obtain the actual value of the d-axis output current and the actual value of the q-axis output current of the energy storage converter under a two-phase rotation coordinate system; Calculating the d-axis output voltage of the energy storage converter under the two-phase rotation coordinate system according to the active power reference value of the energy storage converter and the d-axis output current actual value of the energy storage converter under the two-phase rotation coordinate system; Calculating the d-axis decoupling voltage of the energy storage converter under the two-phase rotating coordinate system according to the d-axis output current actual value of the energy storage converter under the two-phase rotating coordinate system; And superposing the q-axis output voltage of the energy storage converter under the two-phase rotation coordinate system with the d-axis decoupling voltage of the energy storage converter under the two-phase rotation coordinate system to obtain the q-axis modulation voltage of the energy storage converter under the two-phase rotation coordinate system.
4. 4. The oscillation suppression method according to claim 3, wherein the calculating the d-axis output voltage of the energy storage converter in the two-phase rotation coordinate system based on the active power reference value of the energy storage converter and the d-axis output current actual value of the energy storage converter in the two-phase rotation coordinate system includes: proportional integral control is carried out on the difference value between the active power reference value of the energy storage converter and the active power actual value of the energy storage converter, so that a d-axis current reference value of the energy storage converter under a two-phase rotating coordinate system is obtained; and performing proportional integral control on the difference value between the d-axis current reference value of the energy storage converter under the two-phase rotation coordinate system and the d-axis output current actual value of the energy storage converter under the two-phase rotation coordinate system to obtain the d-axis output voltage of the energy storage converter under the two-phase rotation coordinate system.
5. 5. The oscillation suppression method according to claim 3, wherein the calculating the q-axis output voltage of the energy storage converter in the two-phase rotation coordinate system based on the reactive power reference value of the energy storage converter and the q-axis output current actual value of the energy storage converter in the two-phase rotation coordinate system includes: proportional integral control is carried out on the difference value between the reactive power reference value of the energy storage converter and the reactive power actual value of the energy storage converter, so that a q-axis current reference value of the energy storage converter under a two-phase rotation coordinate system is obtained; And performing proportional integral control on the difference value between the q-axis current reference value of the energy storage converter under the two-phase rotation coordinate system and the q-axis output current actual value of the energy storage converter under the two-phase rotation coordinate system to obtain the q-axis output voltage of the energy storage converter under the two-phase rotation coordinate system.
6. 6. The oscillation suppression method according to claim 3, characterized in that, The d-axis decoupling voltage of the energy storage converter under a two-phase rotation coordinate system meets the following conditions , wherein, Represents the d-axis decoupling voltage of the energy storage converter under a two-phase rotation coordinate system, Representing the actual d-axis output current value of the energy storage converter under a two-phase rotation coordinate system, Represents the power frequency angular frequency, A sensing value representing a grid-connected inductance of the energy storage converter; The q-axis decoupling voltage of the energy storage converter under a two-phase rotation coordinate system meets the following conditions: , wherein, Represents the q-axis decoupling voltage of the energy storage converter under a two-phase rotation coordinate system, And the energy storage converter outputs an actual value of current on a q-axis under a two-phase rotation coordinate system.
7. 7. The oscillation suppression method according to claim 1, wherein the calculating the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system based on the three-phase voltage actual value of the new energy station grid-connected point and the output current actual value of the energy storage converter includes: Determining an oscillation suppression current reference value of the energy storage converter under a two-phase static coordinate system according to the three-phase voltage actual value of the new energy station grid-connected point; Determining oscillation compensation voltage of the energy storage converter under a two-phase static coordinate system according to the actual value of the output current of the energy storage converter and an oscillation suppression current reference value of the energy storage converter under the two-phase static coordinate system; and performing anti-Clark conversion on the oscillation compensation voltage of the energy storage converter under the two-phase static coordinate system to obtain the oscillation suppression voltage of the energy storage converter under the three-phase static coordinate system.
8. 8. The method of claim 7, wherein determining the reference value of the oscillation suppression current of the energy storage converter in the two-phase stationary coordinate system according to the actual value of the three-phase voltage of the new energy station grid-connected point comprises: Performing Clark conversion on the three-phase voltage actual values of the new energy station grid-connected points to obtain an alpha-axis voltage actual value and a beta-axis voltage actual value of the new energy station grid-connected points under a two-phase static coordinate system; And carrying out proportional resonance control on the difference value between the preset alpha-axis voltage reference value and the alpha-axis voltage actual value of the new energy station grid-connected point under the two-phase static coordinate system to obtain an alpha-axis oscillation suppression current reference value of the energy storage converter under the two-phase static coordinate system, and carrying out proportional resonance control on the difference value between the preset beta-axis voltage reference value and the beta-axis voltage actual value of the new energy station grid-connected point under the two-phase static coordinate system to obtain a beta-axis oscillation suppression current reference value of the energy storage converter under the two-phase static coordinate system.
9. 9. The oscillation suppression method according to claim 8, wherein the determining the oscillation compensation voltage of the energy storage converter in the two-phase stationary coordinate system according to the actual value of the output current of the energy storage converter and the oscillation suppression current reference value of the energy storage converter in the two-phase stationary coordinate system comprises: Performing Clark conversion on the actual value of the output current of the energy storage converter to obtain an actual value of alpha-axis current and an actual value of beta-axis current of the energy storage converter under a two-phase static coordinate system; proportional resonance control is carried out on the difference value between the alpha-axis oscillation suppression current reference value of the energy storage converter under the two-phase static coordinate system and the alpha-axis current actual value of the energy storage converter under the two-phase static coordinate system, so that alpha-axis oscillation compensation voltage of the energy storage converter under the two-phase static coordinate system is obtained; And carrying out proportional resonance control on the difference value between the beta-axis oscillation suppression current reference value of the energy storage converter under the two-phase static coordinate system and the beta-axis current actual value of the energy storage converter under the two-phase static coordinate system to obtain the beta-axis oscillation compensation voltage of the energy storage converter under the two-phase static coordinate system.
10. 10. The oscillation suppression method according to claim 1, wherein the suppressing oscillation occurring in the new energy flexible dc interconnection system according to the fundamental wave modulation voltage of the energy storage converter in the three-phase stationary coordinate system and the oscillation suppression voltage of the energy storage converter in the three-phase stationary coordinate system comprises: superposing fundamental wave modulation voltage of the energy storage converter under a three-phase static coordinate system and oscillation suppression voltage of the energy storage converter under the three-phase static coordinate system to obtain control voltage of the energy storage converter under the three-phase static coordinate system; Modulating the control voltage of the energy storage converter under a three-phase static coordinate system to obtain a control signal, and controlling the energy storage converter according to the control signal.
11. 11. The oscillation suppression method according to claim 1, characterized in that the oscillation suppression method further comprises: Performing Fourier transformation on the three-phase voltage actual values of the acquired new energy station grid-connected points to obtain voltage amplitude values of the new energy station grid-connected points under different frequencies; and if the voltage amplitude of the new energy station grid-connected point under different frequencies is larger than a preset voltage threshold, determining that the new energy flexible direct current interconnection system oscillates.
12. 12. The utility model provides a new forms of energy flexible direct current interconnected system oscillation suppression device which characterized in that includes: The control module is used for controlling the actual value of the output current of the energy storage converter according to the active power reference value and the reactive power reference value of the energy storage converter to obtain the fundamental wave modulation voltage of the energy storage converter under a three-phase static coordinate system; The calculation module is used for calculating the oscillation suppression voltage of the energy storage converter under a three-phase static coordinate system according to the three-phase voltage actual value of the new energy station grid connection point and the output current actual value of the energy storage converter; And the suppression module is used for suppressing oscillation generated by the new energy flexible direct current interconnection system according to fundamental wave modulation voltage of the energy storage converter under the three-phase static coordinate system and oscillation suppression voltage of the energy storage converter under the three-phase static coordinate system.
13. 13. The oscillation suppression apparatus of claim 12, wherein the control module is specifically configured to: Performing phase-locked loop control on the actual value of the three-phase voltage of the new energy station grid connection point to obtain the synchronous phase of the power grid connected with the new energy flexible direct current interconnection system; Outputting a modulation voltage of the energy storage converter under a two-phase rotation coordinate system according to the synchronous phase of the power grid, the active power reference value of the energy storage converter, the reactive power reference value of the energy storage converter and the output current actual value of the energy storage converter; and performing inverse Pake transformation on the modulation voltage of the energy storage converter under the two-phase rotating coordinate system according to the synchronous phase of the power grid to obtain the fundamental wave modulation voltage of the energy storage converter under the three-phase static coordinate system.
14. 14. The oscillation suppression apparatus of claim 13, wherein the control module is specifically configured to: performing park transformation on the actual value of the output current of the energy storage converter to obtain the actual value of the d-axis output current and the actual value of the q-axis output current of the energy storage converter under a two-phase rotation coordinate system; Calculating the d-axis output voltage of the energy storage converter under the two-phase rotation coordinate system according to the active power reference value of the energy storage converter and the d-axis output current actual value of the energy storage converter under the two-phase rotation coordinate system; Calculating the d-axis decoupling voltage of the energy storage converter under the two-phase rotating coordinate system according to the d-axis output current actual value of the energy storage converter under the two-phase rotating coordinate system; And superposing the q-axis output voltage of the energy storage converter under the two-phase rotation coordinate system with the d-axis decoupling voltage of the energy storage converter under the two-phase rotation coordinate system to obtain the q-axis modulation voltage of the energy storage converter under the two-phase rotation coordinate system.
15. 15. The oscillation suppression apparatus of claim 14, wherein the control module is specifically configured to: proportional integral control is carried out on the difference value between the active power reference value of the energy storage converter and the active power actual value of the energy storage converter, so that a d-axis current reference value of the energy storage converter under a two-phase rotating coordinate system is obtained; and performing proportional integral control on the difference value between the d-axis current reference value of the energy storage converter under the two-phase rotation coordinate system and the d-axis output current actual value of the energy storage converter under the two-phase rotation coordinate system to obtain the d-axis output voltage of the energy storage converter under the two-phase rotation coordinate system.
16. 16. The oscillation suppression apparatus of claim 14, wherein the control module is specifically configured to: proportional integral control is carried out on the difference value between the reactive power reference value of the energy storage converter and the reactive power actual value of the energy storage converter, so that a q-axis current reference value of the energy storage converter under a two-phase rotation coordinate system is obtained; And performing proportional integral control on the difference value between the q-axis current reference value of the energy storage converter under the two-phase rotation coordinate system and the q-axis output current actual value of the energy storage converter under the two-phase rotation coordinate system to obtain the q-axis output voltage of the energy storage converter under the two-phase rotation coordinate system.
17. 17. The oscillation suppression apparatus as defined in claim 14, wherein, The d-axis decoupling voltage of the energy storage converter under a two-phase rotation coordinate system meets the following conditions , wherein, Represents the d-axis decoupling voltage of the energy storage converter under a two-phase rotation coordinate system, Representing the actual d-axis output current value of the energy storage converter under a two-phase rotation coordinate system, Represents the power frequency angular frequency, A sensing value representing a grid-connected inductance of the energy storage converter; The q-axis decoupling voltage of the energy storage converter under a two-phase rotation coordinate system meets the following conditions: , wherein, Represents the q-axis decoupling voltage of the energy storage converter under a two-phase rotation coordinate system, And the energy storage converter outputs an actual value of current on a q-axis under a two-phase rotation coordinate system.
18. 18. The oscillation suppression apparatus of claim 12, wherein the computing module is specifically configured to: Determining an oscillation suppression current reference value of the energy storage converter under a two-phase static coordinate system according to the three-phase voltage actual value of the new energy station grid-connected point; Determining oscillation compensation voltage of the energy storage converter under a two-phase static coordinate system according to the actual value of the output current of the energy storage converter and an oscillation suppression current reference value of the energy storage converter under the two-phase static coordinate system; and performing anti-Clark conversion on the oscillation compensation voltage of the energy storage converter under the two-phase static coordinate system to obtain the oscillation suppression voltage of the energy storage converter under the three-phase static coordinate system.
19. 19. The oscillation suppression apparatus of claim 18, wherein the computing module is specifically configured to: Performing Clark conversion on the three-phase voltage actual values of the new energy station grid-connected points to obtain an alpha-axis voltage actual value and a beta-axis voltage actual value of the new energy station grid-connected points under a two-phase static coordinate system; And carrying out proportional resonance control on the difference value between the preset alpha-axis voltage reference value and the alpha-axis voltage actual value of the new energy station grid-connected point under the two-phase static coordinate system to obtain an alpha-axis oscillation suppression current reference value of the energy storage converter under the two-phase static coordinate system, and carrying out proportional resonance control on the difference value between the preset beta-axis voltage reference value and the beta-axis voltage actual value of the new energy station grid-connected point under the two-phase static coordinate system to obtain a beta-axis oscillation suppression current reference value of the energy storage converter under the two-phase static coordinate system.
20. 20. The oscillation suppression apparatus of claim 19, wherein the computing module is specifically configured to: Performing Clark conversion on the actual value of the output current of the energy storage converter to obtain an actual value of alpha-axis current and an actual value of beta-axis current of the energy storage converter under a two-phase static coordinate system; proportional resonance control is carried out on the difference value between the alpha-axis oscillation suppression current reference value of the energy storage converter under the two-phase static coordinate system and the alpha-axis current actual value of the energy storage converter under the two-phase static coordinate system, so that alpha-axis oscillation compensation voltage of the energy storage converter under the two-phase static coordinate system is obtained; And carrying out proportional resonance control on the difference value between the beta-axis oscillation suppression current reference value of the energy storage converter under the two-phase static coordinate system and the beta-axis current actual value of the energy storage converter under the two-phase static coordinate system to obtain the beta-axis oscillation compensation voltage of the energy storage converter under the two-phase static coordinate system.

Description

New energy flexible direct current interconnection system oscillation suppression method and device Technical Field The application relates to the technical field of new energy, in particular to a method and a device for suppressing oscillation of a new energy flexible direct current interconnection system. Background The flexible direct current transmission system (namely the flexible direct current interconnection system of the new energy) with the new energy is an optimal means for solving the problem of remote transmission and absorption of large-scale new energy due to the advantages of no need of phase-change voltage, flexible control and the like. Wind power, photovoltaic, flexible direct current converters and the like are complex to control, the speed is high, the control frequency band can reach thousands of hertz, and wide-frequency-domain oscillation of a new energy flexible direct current interconnection system is extremely easy to induce. According to the theory of impedance stability, the new energy flexible direct current interconnection system is considered to be caused by lack of damping at a certain non-fundamental frequency. The related art generally realizes the oscillation suppression of the new energy flexible direct current interconnection system by adjusting the damping characteristic of the new energy side or the damping characteristic of the flexible direct current converter side. However, the new energy station (such as a wind power plant) generally comprises a large number of wind power units, the impedance characteristic of the whole wind power plant is optimized by adjusting the impedance characteristic of the wind power units one by one, the whole wind power plant is affected by interaction among the wind power units, the difficulty of the whole adjustment process is high, and the practicality and the inhibition effect of the inhibition method are poor. Disclosure of Invention In order to solve the problems of poor practicality and poor inhibition effect of the inhibition method in the prior art, the application provides a new energy flexible direct current interconnection system oscillation inhibition method and device. In a first aspect, the present application provides a new energy flexible dc interconnection system oscillation suppression method, which may include: And controlling the actual value of the output current of the energy storage converter according to the active power reference value and the reactive power reference value of the energy storage converter to obtain the fundamental wave modulation voltage of the energy storage converter under the three-phase static coordinate system. And calculating the oscillation suppression voltage of the energy storage converter under the three-phase static coordinate system according to the three-phase voltage actual value of the new energy station grid connection point and the output current actual value of the energy storage converter. And suppressing oscillation of the new energy flexible direct current interconnection system according to the fundamental wave modulation voltage of the energy storage converter under the three-phase static coordinate system and the oscillation suppression voltage of the energy storage converter under the three-phase static coordinate system. In some possible implementations, the controlling the actual value of the output current of the energy storage converter according to the active power reference value and the reactive power reference value of the energy storage converter to obtain the fundamental modulation voltage of the energy storage converter under the three-phase static coordinate system includes: And performing phase-locked loop control on the actual value of the three-phase voltage of the new energy station grid connection point to obtain the synchronous phase of the power grid connected with the new energy flexible direct current interconnection system. And outputting the modulation voltage of the energy storage converter under the two-phase rotation coordinate system according to the synchronous phase of the power grid, the active power reference value of the energy storage converter, the reactive power reference value of the energy storage converter and the output current actual value of the energy storage converter. And performing inverse Peak conversion on the modulation voltage of the energy storage converter under the two-phase rotating coordinate system according to the synchronous phase of the power grid to obtain the fundamental wave modulation voltage of the energy storage converter under the three-phase stationary coordinate system. Further, outputting the modulation voltage of the energy storage converter under the two-phase rotation coordinate system according to the synchronous phase of the power grid, the active power reference value of the energy storage converter, the reactive power reference value of the energy storage converter and the output current actual va