CN-122020948-A - Phasor group modeling and resolving method and device for grid-related converter

CN122020948ACN 122020948 ACN122020948 ACN 122020948ACN-122020948-A

Abstract

The invention relates to the technical fields of power systems, new energy grid connection and power electronic simulation, in particular to a phasor group modeling and resolving method and device for a grid-related converter, wherein the method comprises the steps of extracting current dominant frequency components of alternating-current ends of each voltage source converter from a target power grid; the method comprises the steps of calculating a current signal at an output end of an upper bridge arm of an ith three-phase voltage source type converter according to a current dominant frequency component, converting the current signal into a direct current side current frequency component phasor, extracting a voltage dominant frequency component of a direct current end of each voltage source type converter, calculating an alternating current side a-phase voltage of the ith three-phase voltage source type converter according to the voltage dominant frequency component, converting the alternating current side a-phase voltage into an alternating current side voltage frequency component phasor, and carrying out main phase group modeling and resolving on the direct current side current frequency phasor and the alternating current side voltage frequency phasor which are converted at a certain specific frequency. Therefore, the problems of large simulation calculation amount, low simulation efficiency and the like in the related technology are solved.

Inventors

ZHANG SHUQING
SHI KAIYUAN
ZHANG WEIJIE
JIAO RUIQI
TANG SHAOPU

Assignees

清华大学

Dates

Publication Date: 20260512
Application Date: 20251202

Claims (10)

1. The phasor group modeling and resolving method for the grid-related converter is characterized by comprising the following steps of: Extracting current dominant frequency components of alternating current ends of each voltage source type converter in a target power grid, wherein the target power grid comprises a power grid of a plurality of voltage source type converters, each voltage source type converter comprises a direct current side, an alternating current side and k three-phase voltage source type converters, the direct current side is connected with the direct current ends of the k three-phase voltage source type converters, and the alternating current ends of the k three-phase voltage source type converters are connected with the alternating current side; Calculating a current signal of an upper bridge arm output end of the ith three-phase voltage source type converter according to the current dominant frequency component, and converting the current signal of the upper bridge arm output end of the ith three-phase voltage source type converter into a phasor form to obtain a direct-current side current frequency component phasor; Extracting a voltage dominant frequency component of a direct current end of each voltage source type converter from the target power grid; Calculating an alternating current side a-phase voltage of the ith three-phase voltage source type converter according to the voltage dominant frequency component, and converting the alternating current side a-phase voltage of the ith three-phase voltage source type converter into a phasor form to obtain an alternating current side voltage frequency component phasor; And modeling and resolving a main phasor group for the direct-current side current frequency component phasor and the alternating-current side voltage frequency component phasor of each transformation under a specific frequency.
2. The phasor group modeling and resolving method for a grid-oriented converter according to claim 1, wherein the dc side includes a dc link network and k filter circuits, the dc link network is respectively connected to each filter circuit, and each filter circuit is respectively connected to a dc end of each voltage source converter.
3. The phasor group modeling and resolving method for a grid-related converter according to claim 1, wherein the ac side includes k grid-connected circuits and an ac interconnection network, the ac interconnection network is respectively connected to each grid-connected circuit, and each grid-connected circuit is respectively connected to an ac end of each voltage source converter.
4. The method for modeling and resolving phasor groups for grid-oriented converters according to claim 1, wherein the extracting the current dominant frequency component of the ac end of each voltage source converter in the target grid comprises: Under the condition that the alternating-current side current of the three-phase voltage source type converter and the preset three-phase controller reference signal are in positive sequence, the input end three-phase current time domain signal of the ith three-phase voltage source type converter adopts a dominant frequency combination form as follows: the dominant frequency combination form for the port relation function of the upper bridge arm of the ith three-phase voltage source type converter is as follows: Under the condition that the alternating-current side current of the three-phase voltage source type converter and the preset three-phase controller reference signal are both negative sequences, the three-phase current time domain signal of the input end of the ith three-phase voltage source type converter adopts a dominant frequency combination form: the dominant frequency combination form for the port relation function of the upper bridge arm of the ith three-phase voltage source type converter is as follows: Wherein, the The three-phase currents at the input end of the ith three-phase voltage source type converter respectively, For the number of dominant frequency components at the input, 、、 ...... The angular frequency of the current at the input end is respectively, 、、 ...... The current phases of the input ends are respectively, The term that indicates the dc component is located, , , Respectively the port relation function of the upper bridge arm of the ith three-phase voltage source type converter, For the number of port dominant frequency components, 、、 ...... The angular frequency of the current at the input end is respectively, 、、 ...... The current phases of the input ends are respectively, The term that indicates the dc component is located, , 。
5. The method for modeling and resolving a phasor group for a grid-connected inverter according to claim 1, wherein the converting the current signal at the output end of the upper leg of the ith three-phase voltage source type inverter into a phasor form to obtain a dc-side current frequency component phasor comprises: under the condition that the alternating-current side current of the three-phase voltage source type converter and a preset three-phase controller reference signal are in positive sequence, the expression of the direct-current side current frequency phasor is as follows: Under the condition that the alternating-current side current of the three-phase voltage source type converter and the preset three-phase controller reference signal are both negative sequences, the expression of the direct-current side current frequency phasor is as follows: Wherein, the In the form of the phasor of the mth frequency component of the a-phase current on the ac side of a three-phase voltage source converter, the angular frequency of the phasor being , In the form of a phasor of the nth frequency component of the switching signal, the angular frequency of the phasor being , In the form of a phasor of the frequency component of the direct current generated by the m-th frequency component of the a-phase current of the alternating current side and the n-th frequency component of the switching signal under the positive sequence condition, the angular frequency of the phasor is , In the form of a phasor of the frequency component of the direct current generated by the m-th frequency component of the a-phase current of the alternating current side and the n-th frequency component of the switching signal under the negative sequence condition, the angular frequency of the phasor is 。
6. The method for modeling and resolving a phasor set for a grid-oriented converter according to claim 1, wherein the modeling and resolving a main phasor set for the dc-side current frequency component phasor and the ac-side voltage frequency component phasor for each transformation at a specific frequency includes: setting a specific frequency component current phasor except power frequency of a phase at an alternating current side a of a three-phase voltage source type converter Is that Angular frequency of Dominant frequency component of switching signal Is that Angular frequency of And (2) and ; Calculating a first current phasor generated by the current and the switching signal on the direct current side according to the current frequency component phasor on the direct current side, and calculating a first voltage phasor generated by the current and the switching signal on the direct current side according to the first current phasor; calculating a second voltage phasor generated by the voltage and the switching signal on the alternating current side according to the voltage frequency component phasor on the alternating current side and the first voltage phasor, and calculating a second current phasor generated by a second voltage phasor with the angular frequency converted for the first time on the alternating current side according to the second voltage phasor; Calculating a third current phasor generated by the second current phasor on the direct current side according to the direct current side current frequency component phasor and the second current phasor, and calculating a third voltage phasor generated by the second current phasor on the direct current side according to the third current phasor; And calculating a fourth voltage phasor generated by the third voltage phasor on the alternating current side according to the alternating current side voltage frequency component phasor and the third voltage phasor, and calculating the frequency coupling impedance of the secondary transformation and a fourth current phasor generated by the fourth voltage phasor on the alternating current side according to the fourth voltage phasor.
7. Phasor group modeling and solving device for grid-related converter is characterized by comprising: The first extraction module is used for extracting current dominant frequency components of alternating current ends of each voltage source type converter in a target power grid, wherein the target power grid comprises a power grid of a plurality of voltage source type converters, each voltage source type converter comprises a direct current side, an alternating current side and k three-phase voltage source type converters, the direct current side is connected with the direct current ends of the k three-phase voltage source type converters, and the alternating current ends of the k three-phase voltage source type converters are connected with the alternating current side; The first conversion module is used for calculating a current signal of the output end of the upper bridge arm of the ith three-phase voltage source type converter according to the current dominant frequency component and converting the current signal of the output end of the upper bridge arm of the ith three-phase voltage source type converter into a phasor form so as to obtain a direct-current side current frequency component phasor; the second extraction module is used for extracting the voltage dominant frequency component of the direct current end of each voltage source type converter in the target power grid; The second conversion module is used for calculating the a-phase voltage of the alternating current side of the ith three-phase voltage source type converter according to the voltage dominant frequency component and converting the a-phase voltage of the alternating current side of the ith three-phase voltage source type converter into a phasor form so as to obtain the frequency component phasor of the alternating current side voltage; And the modeling and resolving module is used for carrying out main phasor group modeling and resolving on the DC side current frequency phasors and the AC side voltage frequency phasors which are transformed at a certain specific frequency.
8. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor executing the program to implement the phasor set modeling and resolving method for a grid-oriented converter as claimed in any one of claims 1 to 6.
9. A computer program product, characterized in that the computer program/instructions, when executed by a processor, implements the phasor set modeling and resolving method for a grid-oriented converter according to any one of claims 1-6.
10. A computer readable storage medium having stored thereon a computer program, the program being executable by a processor for implementing the phasor set modeling and resolving method for a grid-oriented converter as claimed in any one of claims 1-6.

Description

Phasor group modeling and resolving method and device for grid-related converter Technical Field The invention relates to the technical field of power systems, new energy grid connection and power electronic simulation, in particular to a phasor group modeling and resolving method and device for a grid-related converter. Background In the simulation of the power electronic power grid, when the scale of the electromechanical system in the simulated object system is huge, the power electronic equipment is connected with the electromechanical system through a grid connection point, for example, the grid connected with a large number of new energy field groups is contained, and the main problems of synchronous stability and voltage stability of the electromechanical system are concerned, and the problems of excessively complex model, low simulation speed and large calculation amount can occur due to the fact that a detailed converter model is adopted in the situation. In the stability analysis of the large system level, ripple waves caused by a switching process on a direct current side and sideband harmonics caused on an alternating current side are not important points to be considered, and modeling of switching action details of a converter (hereinafter referred to as a grid-related converter for short) at a grid connection point where power electronic equipment is connected with an alternating current large power grid is neither practical nor necessary. The dynamic phasor method models a circuit by using time-varying phasors, and a dynamic process of rapid change in the circuit is simulated by using k-order dynamic phasors, but from the current theoretical analysis and practical situation, the main links of the system stability problem in a large number of converter grid-connected scenes are transient crossing and sub-super-synchronous frequency band processes instead of harmonic waves of integral multiples of fundamental frequency, and in addition, when the modeling is needed by using phasors of a plurality of frequencies, a corresponding frequency domain model is independently built for each frequency, so that the complexity can be greatly improved. The frequency shift method converts the fundamental frequency signal into a similar direct current signal by shifting the complete frequency spectrum of the signal, and can simulate the fundamental frequency signal with a larger step length, but the frequency shift method is only applicable to a system with the dominant fundamental frequency signal, when the system comprises a plurality of discrete frequency components, the frequency spectrum still has high frequency components after being shifted, smaller step length simulation still needs to be adopted, and the improvement of the calculation efficiency is not obvious. Disclosure of Invention The invention provides a phasor group modeling and resolving method and device for a grid-related converter, which are used for solving the problems of large simulation calculated amount, low simulation efficiency and the like in the related technology. An embodiment of a first aspect of the present invention provides a phasor group modeling and resolving method for a grid-related converter, including the following steps: Extracting current dominant frequency components of alternating current ends of each voltage source type converter in a target power grid, wherein the target power grid comprises a power grid of a plurality of voltage source type converters, each voltage source type converter comprises a direct current side, an alternating current side and k three-phase voltage source type converters, the direct current side is connected with the direct current ends of the k three-phase voltage source type converters, and the alternating current ends of the k three-phase voltage source type converters are connected with the alternating current side; Calculating a current signal of an upper bridge arm output end of the ith three-phase voltage source type converter according to the current dominant frequency component, and converting the current signal of the upper bridge arm output end of the ith three-phase voltage source type converter into a phasor form to obtain a direct-current side current frequency component phasor; Extracting a voltage dominant frequency component of a direct current end of each voltage source type converter from the target power grid; Calculating an alternating current side a-phase voltage of the ith three-phase voltage source type converter according to the voltage dominant frequency component, and converting the alternating current side a-phase voltage of the ith three-phase voltage source type converter into a phasor form to obtain an alternating current side voltage frequency component phasor; And modeling and resolving a main phasor group for the direct-current side current frequency component phasor and the alternating-current side voltage frequency component phasor of each transformation