A method for low-frequency impedance analysis of parallel PSUs, a terminal and a storage medium

Abstract

This invention relates to the field of power electronics technology and discloses a method, terminal, and storage medium for low-frequency impedance analysis of parallel PSUs. In this invention, a low-frequency impedance model of a single PSU is established based on the DC-side voltage variation; then, an input admittance transfer function is established for n PSUs connected in parallel, filtering out the influence of coupling frequencies; finally, an equivalent aggregation is performed to obtain the frequency coupling factor for the n PSUs in parallel; and the low-frequency impedance model of the single PSU, the input admittance transfer function, and the frequency coupling factor are combined to perform low-frequency impedance analysis on the parallel PSUs. The low-frequency impedance model considers the influence of disturbance sources, the influence of input admittance in parallel operation on the model, and finally the influence of frequency coupling on the low-frequency impedance of the parallel PSUs after n PSUs are connected in parallel. This results in a more accurate low-frequency impedance analysis model for parallel PSUs, a greater understanding of the influence of more factors on the low-frequency impedance analysis of parallel PSUs, and better applicability.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to a method for low-frequency impedance analysis of parallel PSUs, a terminal, and a storage medium. Background Technology

[0002] The reliable operation of the data center power system is a prerequisite for the stability of the data center. The data center power supply system contains a large number of power electronic devices in its distribution system, exhibiting a very high concentration of power electronics. Because the equivalent impedance of the data center distribution network is much higher than the impedance of the transmission lines and substations supplying it, interactions occur between the data center power supply units (PSUs) and the distribution network, easily leading to complex low-frequency resonance problems that directly affect the stable operation of the data center power supply system. To address these issues, the following two solutions have been proposed: 1. Obtaining a parallel impedance model of multiple PSUs using online impedance measurement technology, and predicting the stability and resonant frequency of the parallel PSU system based on this model; 2. Assuming a proportional relationship between the equivalent impedances of two PSUs, establishing a low-frequency impedance matrix model of two parallel PSUs using impedance analysis.

[0003] The inventors have found that the related technologies still have at least the following problems: Method 1 obtains the impedance model through impedance measurement, which cannot be used to study the resonance mechanism and parameter influence of a multi-PSU parallel system, and it is difficult to give an effective resonance suppression method; Method 2 requires the PSU and load equivalent impedance to be proportional during the impedance modeling process, which limits the application of this method and cannot be extended to impedance modeling of a multi-PSU parallel system. Summary of the Invention

[0004] The purpose of this invention is to provide a method, terminal, and storage medium for low-frequency impedance analysis of parallel PSUs, so that the influence of other factors in the circuit can be considered more when performing low-frequency impedance analysis of multiple PSUs in parallel, which facilitates the provision of effective resonance suppression methods and has better applicability.

[0005] To address the aforementioned technical problems, embodiments of the present invention provide a low-frequency impedance analysis method for parallel PSUs, comprising:

[0006] A low-frequency impedance model for a single PSU is established based on the DC-side voltage variation. Based on this model, an input admittance transfer function for n PSUs connected in parallel, filtered by the coupling frequency, is established using Kirchhoff's current law. Furthermore, a frequency coupling factor for the n PSUs connected in parallel is obtained through equivalent aggregation, based on the single PSU low-frequency impedance model. Finally, the low-frequency impedance model of the parallel PSUs, the input admittance transfer function, and the frequency coupling factor are combined to obtain a low-frequency impedance model for the parallel PSUs, enabling low-frequency impedance analysis. Here, n is a positive integer greater than or equal to 2.

[0007] Embodiments of the present invention also provide a terminal, comprising: at least one processor; and,

[0008] A memory communicatively connected to at least one processor; wherein the memory stores instructions executable by at least one processor, the instructions being executed by at least one processor to enable at least one processor to perform a parallel PSU low-frequency impedance analysis method as described above.

[0009] Embodiments of the present invention also provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for low-frequency impedance analysis of parallel PSUs.

[0010] In this embodiment of the invention, a low-frequency impedance model for a single PSU is established based on the DC-side voltage variation. Based on this model, an input admittance transfer function for n PSUs connected in parallel, filtered by Kirchhoff's current law, is established. Based on the single PSU model, a frequency coupling factor for the n PSUs connected in parallel is obtained through equivalent aggregation. The low-frequency impedance model for the single PSU, the input admittance transfer function, and the frequency coupling factor are combined to obtain a low-frequency impedance model for the parallel PSUs, which is then used for low-frequency impedance analysis. Here, n is a positive integer greater than or equal to 2. First, a low-frequency impedance model for a single PSU is established based on the DC-side voltage variation. The influence of disturbance sources is considered when establishing this model. Then, the influence of input admittance in parallel operation is considered. Finally, the influence of frequency coupling on the low-frequency impedance of n parallel PSUs is considered. By simultaneously considering these three influencing factors when establishing the parallel PSU low-frequency impedance model, a more accurate analysis model of the parallel PSU low-frequency impedance can be obtained. This provides a clearer understanding of the influence of more factors on the analysis of the parallel PSU low-frequency impedance, facilitating the development of effective resonance suppression methods. Furthermore, it does not limit the relationships between individual PSUs, thus offering better applicability.

[0011] In another example, a low-frequency impedance model for a single PSU is established based on the DC-side voltage variation, including:

[0012] A low-frequency impedance model for a single PSU is established using the first formula;

[0013] The first formula is:

[0014] Among them, Y a (s) represents the input admittance transfer function of a single PSU without considering the influence of coupling frequency, Y c-2 (s) represents a single PSU in f p Input voltage at frequency f p -2f1 frequency input current transfer function, Y c+2 (s -2 ) for a single PSU in f p The transfer function of input current from input voltage at frequency -2f1 to the disturbance frequency, Y a (s -2 ) for a single PSU in f p The input admittance transfer function at a frequency of -2f1, neglecting the influence of coupling frequency, Y s (s -2 ) for in f p The equivalent admittance of a single PSU source side at a frequency of -2f1. By dynamically considering the DC-side voltage when establishing the low-frequency impedance model of a single PSU, more accurate information can be obtained from the resulting low-frequency impedance model of the single PSU, facilitating the analysis of the single PSU.

[0015] In another example, the frequency coupling factor includes:

[0016]

[0017] in: The small-signal component of the disturbance current generated by the coupling frequency. Y represents the small-signal component of the disturbance voltage generated by multiple PSUs connected in parallel input ports. ci+2 (s), Y ci-2 (s) is the frequency transfer function of the i-th (i = 1, 2, 3…n) PSU coupling, Y ai (s -2 () represents the i-th (i = 1, 2, 3…n) PSU at frequency f1-2f, without considering the effects of frequency coupling. p Input admittance at Y g (s-2) is f1-2f p Admittance at the specified frequency. By considering the influence of coupling factors caused by coupling during parallel operation on the low-frequency impedance analysis of the entire parallel PSU circuit, a more accurate low-frequency impedance model of the parallel PSU can be established, thus improving the accuracy of the analysis.

[0018] In another example, the low-frequency impedance analysis method for parallel PSUs also includes:

[0019] A new low-frequency impedance model for a single PSU is obtained by processing the parallel PSU low-frequency impedance model using Kirchhoff's current law. Low-frequency impedance analysis of a single PSU is then performed using this new model. By separating the new single PSU low-frequency impedance model from the parallel PSU low-frequency impedance model, which considers DC-side voltage dynamics and frequency coupling, a more accurate single PSU low-frequency impedance can be obtained compared to the original model. This new model better reflects real-world conditions and facilitates better impedance analysis of a single PSU. Attached Figure Description

[0020] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0021] Figure 1 This is a flowchart of a low-frequency impedance analysis method for a parallel PSU according to an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the PSU composition in a parallel PSU low-frequency impedance analysis method according to an embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram of a multi-PSU parallel structure in a low-frequency impedance analysis method for parallel PSUs according to an embodiment of the present invention.

[0024] Figure 4 This is a schematic diagram of a small-signal model under the disturbance frequency of multiple PSUs in parallel, according to an embodiment of the present invention, in a low-frequency impedance analysis method for parallel PSUs.

[0025] Figure 5 This is a schematic diagram of a small-signal model at the parallel coupling frequency of multiple PSUs in a low-frequency impedance analysis method according to an embodiment of the present invention.

[0026] Figure 6 This is a schematic diagram of a terminal structure according to another embodiment of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the various embodiments of the present invention to facilitate a better understanding of this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various changes and modifications based on the following embodiments. The division of the various embodiments below is for ease of description and should not constitute any limitation on the specific implementation of the present invention. The various embodiments can be combined with and referenced by each other without contradiction.

[0028] One embodiment of the present invention relates to a low-frequency impedance analysis method for parallel PSUs, which can be applied to terminal systems. In this embodiment, a low-frequency impedance model of a single PSU is established based on the DC-side voltage variation; based on the low-frequency impedance model of the single PSU, an input admittance transfer function for n PSUs in parallel, filtered by the coupling frequency, is established using Kirchhoff's current law; based on the low-frequency impedance model of the single PSU, a frequency coupling factor for the n PSUs in parallel is obtained through equivalent aggregation; the low-frequency impedance model of the single PSU, the input admittance transfer function, and the frequency coupling factor are combined to obtain a low-frequency impedance model for parallel PSUs, which is used to perform low-frequency impedance analysis on the parallel PSUs; wherein, n is a positive integer greater than or equal to 2. First, a low-frequency impedance model for a single PSU is established based on the DC-side voltage variation. The influence of disturbance sources is considered when establishing this model. Then, the impact of input admittance in parallel operation is considered. Finally, the influence of frequency coupling on the low-frequency impedance of n parallel PSUs is considered. By simultaneously considering these three influencing factors when establishing the parallel PSU low-frequency impedance model, a more accurate analysis model of the parallel PSU low-frequency impedance can be obtained. This provides a clearer understanding of the influence of more factors on the parallel PSU low-frequency impedance analysis, facilitating the development of effective resonance suppression methods. Furthermore, it does not limit the relationships between individual PSUs, thus offering better applicability. The implementation details of the parallel PSU low-frequency impedance analysis method in this embodiment are described below. These details are provided for ease of understanding and are not essential for implementing this solution.

[0029] like Figure 1 As shown, in step 101, a low-frequency impedance model of the single PSU is established based on the DC-side voltage change.

[0030] In one example, establishing a single PSU low-frequency impedance model based on DC-side voltage variation includes: establishing the single PSU low-frequency impedance model using a first formula;

[0031] The first formula is: Among them, Y a(s) represents the input admittance transfer function of a single PSU without considering the influence of coupling frequency, Y c-2 (s) represents a single PSU in f p Input voltage at frequency f p -2f1 frequency input current transfer function, Y c+2 (s -2 ) for a single PSU in f p The transfer function of input current from input voltage at frequency -2f1 to the disturbance frequency, Y a (s -2 ) for a single PSU in f p The input admittance transfer function at a frequency of -2f1, neglecting the influence of coupling frequency, Y s (s -2 ) for in f p The equivalent source-side admittance of a single PSU at a frequency of -2f1. In practical applications, each PSU can consist of a PFC and a DC-DC converter. Figure 2 This is a schematic diagram of a single PSU structure. Since the DC-DC converter is a constant power module, modeling a single PSU mainly involves modeling the low-frequency impedance of the single PFC. During modeling, adding a disturbance source on the AC side allows us to obtain the admittance of the single PFC AC disturbance voltage to the AC current at different frequencies.

[0032]

[0033]

[0034]

[0035] In the formula: The input current is a small-signal component. This represents the input voltage disturbance component. Considering the influence of source-side impedance and DC-side voltage dynamics, combining equations (1), (2), and (3), a complete single PFC input impedance model can be established as follows:

[0036]

[0037] In the formula: is in f p The equivalent admittance of a single PSU source side at a frequency of -2f1. By dynamically considering the DC-side voltage when establishing the low-frequency impedance model of a single PSU, more accurate information can be obtained from the resulting low-frequency impedance model of the single PSU, facilitating the analysis of the single PSU.

[0038] In step 102, based on the low-frequency impedance model of a single PSU, the input admittance transfer function of n PSUs connected in parallel, which filters out the influence of coupling frequency, is established using Kirchhoff's current law.

[0039] In one example, the input admittance transfer function includes:

[0040] Where: s is the complex frequency, Y ai (s) represents the i-th PSU at frequency f after filtering out the effects of frequency coupling. p The input admittance at point i = 1, 2, 3…n.

[0041] In step 103, based on the low-frequency impedance model of a single PSU, the frequency coupling factors of n PSUs in parallel are obtained through equivalent aggregation.

[0042] In one example, the frequency coupling factor includes:

[0043] Where: (i = 1, 2, 3…n) represents the small-signal component of the disturbance current generated by the coupling frequency, represents the small-signal component of the disturbance voltage generated by the parallel input ports of multiple PSUs, and are the coupling frequency transfer functions of the i-th (i = 1, 2, 3…n) PSU, and is the frequency transfer function of the i-th (i = 1, 2, 3…n) PSU at frequency f1-2f when the frequency coupling effect is not considered. p The input admittance at point Yg(s-2) is f1-2f p Admittance at a specific frequency. By considering the impact of coupling factors caused by coupling in parallel circuits on the low-frequency impedance analysis of the entire parallel PSU, a more accurate low-frequency impedance model of the parallel PSU can be established, improving the accuracy of the analysis. In specific implementation, based on the admittance model of a single PSU, an equivalent aggregation is used to establish a low-frequency impedance model containing n parallel PSUs. Figure 3 This is a schematic diagram of n PSUs connected in parallel.

[0044] Furthermore, in Figure 3 After taking into account the interference of the perturbation frequency, we can obtain Figure 4 Schematic diagram of a small-signal model under the disturbance frequency of multiple PSUs in parallel. Figure 3 After taking into account the interference of the coupling frequency, we can obtain Figure 5 Schematic diagram of a small-signal model under the coupling frequency of multiple PSUs in parallel. Figure 4 The input current on the grid side is:

[0045]

[0046] In formula (5) Expressions can be obtained through Figure 5 The system model under the multiple PSU parallel coupling frequency was further obtained.

[0047] Figure 5 At frequency f1-2f pThe admittance model is as follows:

[0048]

[0049] Figure 4 and Figure 5 For a controlled current source, the following relationship exists.

[0050]

[0051]

[0052] From equations (6) and (7), the relationship between them can be obtained as follows:

[0053]

[0054] Combining equation (8), the admittance of the coupled frequency component at the perturbation frequency, i.e., the coupling factor, can be obtained through equivalent aggregation.

[0055]

[0056] In step 104, the low-frequency impedance model of a single PSU, the input admittance transfer function, and the frequency coupling factor are combined to obtain the low-frequency impedance model of a parallel PSU, and low-frequency impedance analysis is performed on the parallel PSU; where n is a positive integer greater than or equal to 2.

[0057] In one example, the low-frequency impedance model of the parallel PSU includes:

[0058]

[0059] Among them, Y ai (s -2 () represents the i-th (i = 1, 2, 3…n) PSU at frequency f1-2f, without considering the effects of frequency coupling. p Input admittance at Y g (s -2 ) is f1-2f p Admittance at frequency; Y ai (s) represents the i-th PSU at frequency f after filtering out the effects of frequency coupling. p Input admittance at point i = 1, 2, 3…n; Y ci+2 (s), Y ci-2 (s) is the frequency transfer function of the i-th (i = 1, 2, 3…n) PSU coupling. In a specific implementation, the parallel low-frequency input impedance of the multiple PSUs can be obtained from equations (5) and (10) in the above embodiments.

[0060]

[0061] By establishing a low-frequency impedance model for a single PSU based on DC-side voltage variations, the influence of disturbance sources is considered in the establishment of the single PSU low-frequency impedance model. Then, the influence of input admittance on the model when connected in parallel is considered. Finally, the influence of frequency coupling on the low-frequency impedance of the parallel PSUs is considered. By simultaneously considering these three influencing factors when establishing the low-frequency impedance model of the parallel PSUs, a more accurate low-frequency impedance analysis model of the parallel PSUs can be obtained. The influence of more factors on the low-frequency impedance analysis of the parallel PSUs is clearly understood, which facilitates the provision of effective resonance suppression methods. Furthermore, it does not limit the relationship between individual PSUs, thus having better applicability.

[0062] In step 105, after obtaining the parallel PSU low-frequency impedance model, the method further includes: determining whether the parallel PSU low-frequency impedance model is stable using the Nyquist stability criterion.

[0063] In one example, as can be seen from Equation (11), the multi-PSU parallel low-frequency impedance model is a single-input single-output model. The stability of the system can be analyzed by the Nyquist stability criterion, which effectively simplifies the complexity of stability analysis.

[0064] Step 106 further includes: processing the parallel PSU low-frequency impedance model using Kirchhoff's current law to obtain a new single PSU low-frequency impedance model; and performing low-frequency impedance analysis on the single PSU using the new single PSU low-frequency impedance model.

[0065] In one example, the new single PSU low-frequency impedance model includes:

[0066]

[0067] In the formula: Y am (s) represents the m-th PSU at frequency f1-2f when frequency coupling is not considered. p Input admittance at Y cm+2 (s -2 ) is the m-th PSU in f p Input voltage at frequency f p The transfer function of the input current at frequency -2f1. In specific implementation, in order to analyze the interaction between different PSUs in the multi-PSU parallel structure, a low-frequency impedance model of the m-th PSU in the multi-PSU parallel system is established. When the influence of the m-th component is not present, equations (7) and (8) can be rewritten as follows:

[0068]

[0069]

[0070] Combining equations (6), (12), and (13), the equivalent admittance of the coupled frequency component at the disturbance frequency can be obtained as follows:

[0071]

[0072] From equation (14), the low-frequency input impedance of the m-th PSU in the parallel PSU configuration can be obtained as follows:

[0073]

[0074] By separating a new single PSU low-frequency impedance model from the parallel PSU low-frequency impedance model established after considering DC-side voltage dynamics and frequency coupling, a new single PSU low-frequency impedance model can be obtained that is more accurate than the original single PSU low-frequency impedance model. This new single PSU low-frequency impedance model is more in line with the actual situation and can help to better perform impedance analysis on a single PSU.

[0075] In this embodiment, a low-frequency impedance model for a single PSU is established based on the DC-side voltage variation. Based on this model, an input admittance transfer function for n PSUs connected in parallel, filtered by Kirchhoff's current law, is established. Then, based on the single PSU model, a frequency coupling factor for the n PSUs connected in parallel is obtained through equivalent aggregation. Finally, the low-frequency impedance model for the single PSU, the input admittance transfer function, and the frequency coupling factor are combined to obtain a low-frequency impedance model for the parallel PSUs, which is used for low-frequency impedance analysis. Here, n is a positive integer greater than or equal to 2. First, a low-frequency impedance model for a single PSU is established based on the DC-side voltage variation. The influence of disturbance sources is considered when establishing this model. Then, the influence of input admittance in parallel operation is considered. Finally, the influence of frequency coupling on the low-frequency impedance of n parallel PSUs is considered. By simultaneously considering these three influencing factors when establishing the parallel PSU low-frequency impedance model, a more accurate analysis model of the parallel PSU low-frequency impedance can be obtained. This provides a clearer understanding of the influence of more factors on the analysis of the parallel PSU low-frequency impedance, facilitating the development of effective resonance suppression methods. Furthermore, it does not limit the relationships between individual PSUs, thus offering better applicability.

[0076] The steps described above are for clarity only. In practice, they can be combined into one step or some steps can be broken down into multiple steps. As long as they include the same logical relationship, they are all within the scope of protection of this patent. Adding insignificant modifications or introducing insignificant designs to the algorithm or process, but without changing the core design of the algorithm and process, are also within the scope of protection of this patent.

[0077] Another embodiment of the present invention relates to a terminal, such as Figure 6 As shown, it includes at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the parallel PSU low-frequency impedance analysis method as described above.

[0078] The memory and processor are connected via a bus, which can include any number of interconnecting buses and bridges, connecting various circuits of one or more processors and memories. The bus can also connect various other circuits, such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and will not be described further herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be a single element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by the processor is transmitted over the wireless medium via an antenna, which further receives data and transmits it to the processor.

[0079] The processor manages the bus and general processing, and also provides various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory is used to store data used by the processor during operation.

[0080] The sixth embodiment of the present invention relates to a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the above-described method embodiments.

[0081] That is, those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0082] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the present invention.

Claims

1. A method for low-frequency impedance analysis of parallel PSUs, characterized in that, include: A low-frequency impedance model for a single PSU is established based on the DC-side voltage variation. Based on the low-frequency impedance model of the single PSU, the input admittance transfer function of n PSUs connected in parallel, which filters out the influence of coupling frequency, is established by Kirchhoff's current law. Based on the single PSU low-frequency impedance model, the frequency coupling factor of n PSUs in parallel is obtained through equivalent aggregation; The low-frequency impedance model of the single PSU, the input admittance transfer function, and the frequency coupling factor are combined to obtain the low-frequency impedance model of the parallel PSU for low-frequency impedance analysis. Where n is a positive integer greater than or equal to 2.

2. The low-frequency impedance analysis method for parallel PSUs according to claim 1, characterized in that, The process of establishing a low-frequency impedance model for a single PSU based on DC-side voltage changes includes: The low-frequency impedance model of the single PSU is established using the first formula; The first formula is: ; in, The input admittance transfer function for a single PSU without considering the effect of coupling frequency. For a single PSU in f p Input voltage at frequency f p -2 f 1. Frequency input current transfer function For a single PSU in f p -2 f The input current transfer function from the input voltage at frequency 1 to the disturbance frequency. For a single PSU in f p -2 f The input admittance transfer function at frequency 1, without considering the influence of coupling frequency. In order to be in f p -2 f Equivalent admittance of a single PSU source at frequency 1.

3. The low-frequency impedance analysis method for parallel PSUs according to claim 1, characterized in that, The input admittance transfer function includes: ； in: s For complex frequencies, To filter out the effects of frequency coupling, the first i Each PSU at frequency f p Input admittance at the location, i =1,2,3 …n .

4. The low-frequency impedance analysis method for parallel PSUs according to claim 1, characterized in that, The frequency coupling factor includes: ； in: The small-signal component of the disturbance current generated by the coupling frequency. This refers to the small-signal component of the disturbance voltage generated by multiple PSUs connected in parallel input ports. For the first i PSUs in f p -2 f The input current transfer function from the input voltage at frequency 1 to the disturbance frequency. For the first i PSUs in f p Input voltage at frequency f p -2 f 1. Frequency input current transfer function Let f1-2fp be the input admittance of the i-th PSU at frequency f1-2fp, without considering the effects of frequency coupling. The admittance at the frequency f1-2fp i =1,2,3 …n .

5. The low-frequency impedance analysis method for parallel PSUs according to claim 1, characterized in that, The parallel PSU low-frequency impedance model includes: ； in, To disregard the effects of frequency coupling, the first i Each PSU at frequency f 1-2 f p Input admittance at the location, Y g ( s -2 )for f 1-2 f p Admittance at the frequency; To filter out the effects of frequency coupling, the first i Each PSU at frequency f p Input admittance at the location ； For the first i PSUs in f p -2 f The input current transfer function from the input voltage at frequency 1 to the disturbance frequency. For the first i PSUs in f p Input voltage at frequency f p -2 f 1. Frequency input current transfer function i =1,2,3 …n .

6. The low-frequency impedance analysis method for parallel PSUs according to claim 5, characterized in that, After obtaining the low-frequency impedance model of the parallel PSU, the following is also included: The stability of the parallel PSU low-frequency impedance model is determined by the Nyquist stability criterion.

7. The low-frequency impedance analysis method for parallel PSUs according to claim 1, characterized in that, Also includes: A new single PSU low-frequency impedance model is obtained by processing the parallel PSU low-frequency impedance model using Kirchhoff's current law. Low-frequency impedance analysis of a single PSU is performed using the new single PSU low-frequency impedance model.

8. The low-frequency impedance analysis method for parallel PSUs according to claim 7, characterized in that, The new single PSU low-frequency impedance model includes: ； in: Let f1-2fp be the input admittance of the i-th PSU at frequency f1-2fp, without considering the effects of frequency coupling. The admittance at the frequency f1-2fp; For the first i PSUs in f p Input voltage at frequency f p -2 f 1. Frequency input current transfer function; To disregard the effects of frequency coupling, the first m Each PSU at frequency f 1-2 f p Input admittance at the location, For the first m PSUs in f p -2 f The input current transfer function from the input voltage at frequency 1 to the disturbance frequency. i =1,2,3 …n ; m =1,2,3 …n .

9. A terminal, characterized in that, include: At least one processor; as well as, A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the parallel PSU low-frequency impedance analysis method as described in any one of claims 1 to 8.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the low-frequency impedance analysis method for parallel PSUs as described in any one of claims 1 to 8.

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