Modeling method, device and equipment of filter circuit, computer readable storage medium and computer program product

Abstract

The invention provides a modeling method, device and equipment of a filter circuit, a computer readable storage medium and a computer program product. The method comprises the following steps: based on a loop equation of a filter circuit, determining a first conversion relationship among a filtered phase line voltage, a phase line voltage before filtering and a filtered phase current, and determining a second conversion relationship among the phase current before filtering, the phase line voltage before filtering and the filtered phase current; based on the first conversion relation, determining a plurality of first logic operation units included in the voltage module and a connection relation between the first logic operation units; based on the second conversion relation, determining a plurality of second logic operation units included in the current module and a connection relation between the second logic operation units; and constructing a simulation model of the filter circuit based on the connection relationship between the first logical operation units and the connection relationship between the second logical operation units. According to the invention, the modeling accuracy of the filter circuit can be improved.

Description

Technical Field

[0001] The present application relates to the field of computer technology, and in particular to a modeling method, device, equipment, computer-readable storage medium and computer program product for a filter circuit. Background Art

[0002] Signals usually contain multiple frequency components. Filter circuits can remove or weaken unnecessary frequency components and retain useful signals. Therefore, filter circuits play an important role in signal processing. With the rapid development of computer technology, filter circuit modeling is increasingly dependent on digital tools. Through software simulation and emulation, filter circuit design can be optimized and experimental cost and time can be reduced. Filter circuit modeling is not only used in traditional electronic and electrical engineering fields, but also expanded to biomedicine, automobile, aerospace and other fields.

[0003] In related technologies, filter circuit modeling relies on accurate mathematical models and parameter settings. If the model is inaccurate or the parameters are improperly set, the simulation results will differ greatly from the actual circuit performance. At the same time, over-reliance on modeling software and neglect of in-depth understanding of the filter circuit principle will result in low accuracy in filter circuit modeling. Summary of the invention

[0004] Embodiments of the present application provide a filter circuit modeling method, apparatus, device, computer-readable storage medium, and computer program product, which can improve the modeling accuracy of the filter circuit.

[0005] The technical solution of the embodiment of the present application is implemented as follows:

[0006] An embodiment of the present application provides a modeling method for a filter circuit, the method comprising:

[0007] Based on the loop equation of the filtering circuit, determining a first conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering and the phase current after filtering, and determining a second conversion relationship between the phase current before filtering and the phase line voltage before filtering and the phase current after filtering;

[0008] Based on the first conversion relationship, determining a connection relationship between a plurality of first logic operation units included in a voltage module and the first logic operation unit;

[0009] Based on the second conversion relationship, determining a connection relationship between a plurality of second logic operation units included in the current module and the second logic operation unit;

[0010] A simulation model of the filter circuit is constructed based on the connection relationship between the first logic operation units and the connection relationship between the second logic operation units.

[0011] The present application provides a filter circuit modeling device, including:

[0012] A first determination module is used to determine a first conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering and the phase current after filtering based on a loop equation of the filtering circuit, and to determine a second conversion relationship between the phase current before filtering and the phase line voltage before filtering and the phase current after filtering;

[0013] a second determining module, configured to determine a connection relationship between a plurality of first logic operation units included in a voltage module and the first logic operation unit based on the first conversion relationship;

[0014] a third determining module, configured to determine a connection relationship between a plurality of second logic operation units included in the current module and the second logic operation unit based on the second conversion relationship;

[0015] A model building module is used to build a simulation model of the filter circuit based on the connection relationship between the first logic operation units and the connection relationship between the second logic operation units.

[0016] An embodiment of the present application provides an electronic device, the electronic device comprising:

[0017] A memory for storing computer executable instructions or computer programs;

[0018] The processor is used to implement the modeling method of the filter circuit provided in the embodiment of the present application when executing the computer executable instructions or computer program stored in the memory.

[0019] An embodiment of the present application provides a computer-readable storage medium storing computer-executable instructions or a computer program for implementing the modeling method of the filter circuit provided in the embodiment of the present application when executed by a processor.

[0020] An embodiment of the present application provides a computer program product, including computer executable instructions or a computer program. When the computer executable instructions or the computer program are executed by a processor, the modeling method of the filter circuit provided in the embodiment of the present application is implemented.

[0021] The embodiments of the present application have the following beneficial effects:

[0022] By using the embodiment of the present application, based on the loop equation of the filter circuit, the first conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering and the phase current after filtering is determined, and the second conversion relationship between the phase current before filtering and the phase line voltage before filtering and the phase current after filtering is determined, and then based on the first conversion relationship, the connection relationship between the multiple first logic operation units included in the voltage module and the first logic operation unit is determined, and then based on the second conversion relationship, the connection relationship between the multiple second logic operation units and the second logic operation unit included in the current module is determined, and then based on the connection relationship between the first logic operation units and the connection relationship between the second logic operation units, the simulation model of the filter circuit is constructed. In this way, based on the loop equation of the filter circuit, the conversion relationship between the phase line voltage before filtering, the phase line voltage after filtering, the phase current before filtering, and the phase current after filtering is determined, so that based on the conversion relationship, the connection relationship between the multiple logic operation units and the logic operation units included in the voltage module and the current module of the simulation model is determined, avoiding the direct construction of the simulation model based on the circuit connection structure of the filter circuit, and improving the modeling accuracy of the filter circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of an application mode of a modeling method for a filter circuit provided in an embodiment of the present application;

[0024] Figure 2 is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application;

[0025] Figure 3A It is a first flow chart of the modeling method of the filter circuit provided in the embodiment of the present application;

[0026] Figure 3B is a second flow chart of the modeling method of the filter circuit provided in the embodiment of the present application;

[0027] Figure 3C is a third flow chart of the modeling method of the filter circuit provided in the embodiment of the present application;

[0028] Figure 3D is a fourth flow chart of the modeling method of the filter circuit provided in an embodiment of the present application;

[0029] Figure 3E is a fifth flow chart of the modeling method of the filter circuit provided in the embodiment of the present application;

[0030] Figure 4 It is a schematic diagram of the modeling process of the AC three-phase LC filter circuit simulation model provided in the embodiment of the present application;

[0031] Figure 5It is a schematic diagram of an AC three-phase LC balanced filter circuit provided in an embodiment of the present application;

[0032] Figure 6 is a schematic diagram of the operation logic of the first voltage module provided in an embodiment of the present application;

[0033] Figure 7 is a schematic diagram of the operation logic of the second voltage module provided in an embodiment of the present application;

[0034] Figure 8 is the output variable u provided in the embodiment of the present application AB Schematic diagram of voltage module operation logic;

[0035] Fig. 9 is the output variable i provided in the embodiment of the present application a Schematic diagram of the current module operation logic;

[0036] Fig.10 It is a schematic diagram of a simulation model of an AC three-phase LC filter circuit provided in an embodiment of the present application;

[0037] Fig.11 It is a schematic diagram of an AC three-phase LC unbalanced filter circuit provided in an embodiment of the present application;

[0038] Fig.12 is the output variable u provided in the embodiment of the present application A Schematic diagram of voltage module operation logic;

[0039] Fig.13 is the output variable i of the unbalanced filter circuit provided in the embodiment of the present application a Schematic diagram of the current module operation logic;

[0040] Fig.14 It is a schematic diagram of a simulation model of an AC three-phase LC unbalanced filter circuit provided in an embodiment of the present application;

[0041] Fig.15 is a schematic diagram of a three-phase line voltage waveform before filtering provided in an embodiment of the present application;

[0042] Fig.16 is a schematic diagram of a three-phase current waveform after filtering provided in an embodiment of the present application;

[0043] Fig.17 is a schematic diagram of a three-phase line voltage waveform after filtering provided in an embodiment of the present application;

[0044] Fig.18 is a schematic diagram of three-phase current waveforms before filtering provided in an embodiment of the present application;

[0045] Fig.19is a schematic diagram of comparing the output variable A-phase voltage waveforms provided in an embodiment of the present application;

[0046] Fig. 20 is a schematic diagram for comparing the waveforms of the phase current of phase A of the output variable provided in an embodiment of the present application;

[0047] Fig.21 1 is a schematic diagram of comparing the output variable B-phase voltage waveform provided in an embodiment of the present application;

[0048] Fig. 22 1 is a schematic diagram of comparing the waveforms of the phase current of the output variable B phase provided in an embodiment of the present application;

[0049] Fig.23 is a schematic diagram of comparing the output variable C-phase voltage waveform provided in an embodiment of the present application;

[0050] Fig.24 It is a schematic diagram for comparing the output variable C-phase current waveform provided in an embodiment of the present application.

[0051] It should be pointed out that the above-mentioned "first" and "second" are only used to distinguish different solutions, and do not represent the degree of superiority or inferiority of the solutions or the priority in the implementation process. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings. The described embodiments should not be regarded as limiting the present application. All other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of this application.

[0053] In the following description, reference is made to “some embodiments”, which describe a subset of all possible embodiments, but it will be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0054] In the following description, the terms "first\second\third" involved are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first\second\third" can be interchanged with a specific order or sequence where permitted, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0055] In the embodiments of the present application, the term "module" or "unit" refers to a computer program or a part of a computer program with a predetermined function, and works together with other related parts to achieve a predetermined goal, and can be implemented in whole or in part by using software, hardware (such as processing circuits or memories) or a combination thereof. Similarly, a processor (or multiple processors or memories) can be used to implement one or more modules or units. In addition, each module or unit can be part of an overall module or unit that includes the function of the module or unit.

[0056] Unless otherwise defined, all technical and scientific terms used in the embodiments of the present application have the same meanings as those commonly understood by those skilled in the art. The terms used in the embodiments of the present application are only for the purpose of describing the embodiments of the present application and are not intended to limit the present application.

[0057] Before further describing the embodiments of the present application in detail, the nouns and terms involved in the embodiments of the present application are explained. The nouns and terms involved in the embodiments of the present application are subject to the following interpretations.

[0058] 1) AC three-phase inductor-capacitor (LC) filter circuit: It is a circuit used in the field of power electronics and signal processing. It is mainly composed of inductor (L) and capacitor (C) components and is used to filter AC three-phase power supply or signal.

[0059] 2) Matrix Laboratory Simulation Software (MATLAB): It is a multi-purpose numerical calculation and scientific simulation software, widely used in engineering calculation, control design, signal processing, communication, image processing and other fields.

[0060] 3) Loop equation: A set of equations used in circuit analysis to describe the relationship between current and voltage in each loop in a circuit.

[0061] 4) First-order inertia link: It describes a simple linear time-invariant system whose output signal responds to the input signal with the characteristics of a first-order differential equation.

[0062] 5) Damping coefficient: It is the ratio between load impedance and system output impedance, which affects the circuit or system's ability to control signals.

[0063] Embodiments of the present application provide a filter circuit modeling method, apparatus, device, computer-readable storage medium, and computer program product, which can improve the modeling accuracy of the filter circuit.

[0064] The following describes an exemplary application of the electronic device provided in the embodiment of the present application. The electronic device provided in the embodiment of the present application can be implemented as various types of terminals such as a laptop computer, a tablet computer, a desktop computer, etc., and can also be implemented as a server. The following describes an exemplary application when the device is implemented as a server.

[0065] See also Figure 1 , Figure 1 Schematic diagram of the application mode of the modeling method of the filter circuit provided in the embodiment of the present application, for example, Figure 1 The server 200, the network 300 and the terminal 400 are involved. The terminal 400 is connected to the server 200 via the network 300. The network 300 can be a wide area network or a local area network, or a combination of the two.

[0066] In the modeling process of the filter circuit, the user triggers the modeling instruction on the terminal 400, and the terminal 400 responds to the user's modeling instruction and sends the modeling request to the server 200. The server 200 responds to the modeling request, obtains the filter circuit information, and analyzes the filter circuit principle in combination with Kirchhoff's voltage law and Kirchhoff's current law to obtain the loop equation of the filter circuit. Based on the loop equation of the filter circuit, the first conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering and the phase current after filtering is determined, and the second conversion relationship between the phase current before filtering and the phase line voltage before filtering and the phase current after filtering is determined. Based on the first conversion relationship, the connection relationship between the multiple first logic operation units included in the voltage module and the first logic operation unit is determined; based on the second conversion relationship, the connection relationship between the multiple second logic operation units included in the current module and the second logic operation unit is determined; based on the connection relationship between the first logic operation units and the connection relationship between the second logic operation units, the simulation model of the filter circuit is constructed, and the simulation model result is returned to the terminal 400. The terminal 400 receives and displays the simulation model result.

[0067] See also Figure 2 , Figure 2 is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application, the electronic device may be a terminal or a server, Figure 2 The electronic device 500 shown includes: at least one processor 410, a memory 450, and at least one network interface 420. The various components in the electronic device 500 are coupled together via a bus system 440. It is understood that the bus system 440 is used to achieve connection and communication between these components. In addition to the data bus, the bus system 440 also includes a power bus, a control bus, and a status signal bus. However, for the sake of clarity, the bus system 440 is not described in detail. Figure 2 Various buses are labeled as bus system 440 .

[0068] The processor 410 can be an integrated circuit chip with signal processing capabilities, such as a general-purpose processor, a digital signal processor (DSP), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc., where the general-purpose processor can be a microprocessor or any conventional processor, etc.

[0069] The memory 450 may be removable, non-removable, or a combination thereof. Exemplary hardware devices include solid-state memory, hard disk drives, optical disk drives, etc. The memory 450 may optionally include one or more storage devices that are physically remote from the processor 410.

[0070] The memory 450 includes a volatile memory or a non-volatile memory, and may also include both volatile and non-volatile memories. The non-volatile memory may be a read-only memory (ROM), and the volatile memory may be a random access memory (RAM). The memory 450 described in the embodiments of the present application is intended to include any suitable type of memory.

[0071] In some embodiments, memory 450 can store data to support various operations, examples of which include programs, modules, and data structures, or a subset or superset thereof, as exemplarily described below.

[0072] The operating system 451 includes system programs for processing various basic system services and performing hardware-related tasks, such as a framework layer, a core library layer, a driver layer, etc., which are used to implement various basic businesses and process hardware-based tasks.

[0073] The network communication module 452 is used to reach other electronic devices via one or more (wired or wireless) network interfaces 420. Exemplary network interfaces 420 include: Bluetooth, Wireless Authentication (WiFi), and Universal Serial Bus (USB).

[0074] In some embodiments, the device provided in the embodiments of the present application can be implemented in software. Figure 2 A modeling device 455 of a filter circuit stored in a memory 450 is shown, which may be software in the form of a program and a plug-in, etc., and includes the following software modules: a first determination module 4551, a second determination module 4552, a third determination module 4553, and a model building module 4554. These modules are logical, and therefore may be arbitrarily combined or further split according to the functions implemented. The functions of each module will be described below.

[0075] In some embodiments, the terminal or server can implement the modeling method of the filter circuit provided in the embodiment of the present application by running various computer executable instructions or computer programs. For example, computer executable instructions can be commands, machine instructions or software instructions at the microprogram level. The computer program can be a native program or software module in the operating system; it can be a local (Native) application (APPlication, APP), that is, a program that needs to be installed in the operating system to run, such as cloud computing APP or instant messaging APP; it can also be a small program that can be embedded in any APP, that is, a program that can be run only by downloading it to a browser environment. In short, the above-mentioned computer executable instructions can be instructions in any form, and the above-mentioned computer program can be an application, module or plug-in in any form.

[0076] The modeling method of the filter circuit provided in the embodiment of the present application will be explained in combination with the exemplary application and implementation of the server device provided in the embodiment of the present application.

[0077] The following describes the modeling method of the filter circuit provided by the embodiment of the present application. As mentioned above, the electronic device that implements the modeling method of the filter circuit of the embodiment of the present application can be a terminal, a server, or a combination of the two. Next, the modeling method of the filter circuit provided by the embodiment of the present application is described by taking the electronic device as a server as an example. Figure 3A , Figure 3A is a first flow chart of the modeling method of the filter circuit provided in the embodiment of the present application, which will be combined with Figure 3A The steps shown are explained.

[0078] In step 301, based on the loop equation of the filtering circuit, a first conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering and the phase current after filtering is determined, and a second conversion relationship between the phase current before filtering and the phase line voltage before filtering and the phase current after filtering is determined.

[0079] Here, the filter circuit can be an AC three-phase inductor-capacitor (LC) filter circuit. The connection modes of the filter circuit include Y-type connection and triangle connection. Each phase in the filter circuit contains an inductor element and a capacitor element, which are used to filter the AC three-phase power supply or signal. The loop equation is a set of equations used to describe the relationship between the current and voltage of each loop in the filter circuit. The loop refers to a closed path in the filter circuit. You can return to the starting point along this closed path. The loop equation of the filter circuit is established based on Kirchhoff's voltage law and Kirchhoff's current law. The phase line voltage refers to the voltage between any phase line and other phase lines, and the phase current refers to the current flowing through each phase load.

[0080] Take the triangle-connected filter circuit as an example, for example, refer to Figure 5 , Figure 5 : is a schematic diagram of an AC three-phase LC balanced filter circuit provided in an embodiment of the present application. The phase current on phase line A is i a , the phase current on phase line B is i b , the phase current on phase line C is i c , phase current i a , phase current i b , phase current i c are the phase currents before filtering, and the phase current i A , phase current i B , phase current i C The phase currents are filtered. The phase voltage between phase lines A and B is u ab , the phase line voltage between phase lines B and C is u bc , the phase line voltage between phase lines C and A is u ca , phase line voltage u ab , phase line voltage u bc , phase line voltage u ca are the phase line voltages before filtering, and the phase line voltage u AB , phase line voltage u BC , phase line voltage u CA Both are phase line voltages after filtering. a , L b , L c is the single-phase filter inductance value, C ab , C bc , C ca is the filtering single-phase capacitance value.

[0081] In some embodiments, the loop equation includes a first loop equation and a second loop equation, the first loop equation includes the inductance values ​​of the three phases, and the second loop equation includes the capacitance values ​​of the three phases, see Figure 3B , Figure 3B It is a second flow chart of the modeling method of the filter circuit provided in an embodiment of the present application. Figure 3A Step 301 shown may be performed by Figure 3B Steps 3011A to 3013A are implemented as described in detail below.

[0082] In step 3011A, when the inductance values ​​of the three phases are the same, the first loop equation is transformed to obtain a transformed first loop equation.

[0083] Here, the first loop equation is a loop equation established according to Kirchhoff's voltage law. The first loop equation is transformed into a matrix by row and column conversion, and the inductance values ​​of the three phases in the first loop equation are converted to the same inductance value to obtain the converted first loop equation. The converted first loop equation is used to characterize the conversion relationship between the phase current before filtering and the phase line voltage before filtering and the phase line voltage after filtering.

[0084] Take the triangle-connected filter circuit as an example, for example, refer to Figure 5 , Figure 5 : is a schematic diagram of an AC three-phase LC balanced filter circuit provided in an embodiment of the present application. The filter circuit includes loop 501, loop 502 and loop 503. According to Kirchhoff's voltage law, a first loop equation is established in combination with loop 501, loop 502 and loop 503. The first loop equation is shown in formula (1):

[0085]

[0086] Among them, u ab 、u bc 、u ca represents the three phase line voltages before filtering, u AB 、u BC 、u CA Represents the three phase line voltages after filtering, L a , L b , L c Indicates the inductance values ​​of the three phases, Represents the differential result of the three phase currents before filtering.

[0087] The first loop equation is transformed into a matrix with rows and columns. The result of the matrix transformation is shown in formula (2):

[0088]

[0089] Among them, L a , L b , L c Indicates the inductance values ​​of the three phases, represents the differential result of the three phase currents before filtering, u ab 、u bc 、u ca represents the three phase line voltages before filtering, u AB 、u BC 、u CA Represents the three phase line voltages after filtering.

[0090] The inductance values ​​L of the three phases in the first loop equation are a , L b , L c, converted to the same inductance value L, and the converted first loop equation is obtained. The converted first loop equation is shown in formula (3):

[0091]

[0092] in, represents the differential result of the three phase currents before filtering, L represents the inductance value of the three phases, u ab 、u bc Represents the two phase line voltages before filtering, u AB 、u BC Represents the two phase line voltages after filtering.

[0093] In step 3012A, when the capacitance values ​​of the three phases are the same, the second loop equation is transformed to obtain a transformed second loop equation.

[0094] Here, the second loop equation is a loop equation established according to Kirchhoff's current law. The second loop equation is transformed into a matrix by row and column conversion, and the capacitance values ​​of the three phases in the second loop equation are converted into the same capacitance value to obtain the converted second loop equation. The converted second loop equation is used to characterize the conversion relationship between the phase line voltage after filtering and the phase current before filtering and the phase current after filtering.

[0095] Take the triangle-connected filter circuit as an example, for example, refer to Figure 5 , Figure 5 : is a schematic diagram of an AC three-phase LC balanced filter circuit provided in an embodiment of the present application. The filter circuit includes loop 501, loop 502 and loop 503. According to Kirchhoff's current law, a second loop equation is established in combination with loop 501, loop 502 and loop 503. The second loop equation is shown in formula (4):

[0096]

[0097] Among them, i a 、i b 、i c represents the three phase currents before filtering, i A 、i B 、i C Represents the three phase currents after filtering, C ab , C ba , C ca Represents the capacitance values ​​of the three phases, It represents the differential result of the three phase line voltages after filtering.

[0098] The second loop equation is transformed into a matrix with rows and columns. The result of the matrix transformation is shown in formula (5):

[0099]

[0100] Among them, C ab , C bc , C ca Represents the capacitance values ​​of the three phases, Represents the differential result of the three phase line voltages after filtering, i a 、i b 、i c represents the three phase currents before filtering, i A 、i B 、i C Represents the three phase currents after filtering.

[0101] The capacitance values ​​C of the three phases in the second loop equation are ab , C ba , C ca , converted to the same capacitance value C, and the converted second loop equation is obtained. The converted second loop equation is shown in formula (6):

[0102]

[0103] in, represents the differential result of the three phase line voltages after filtering, C represents the capacitance value of the three phases, i a 、i b represents the two phase currents before filtering, i A 、i B Represents the two phase currents after filtering.

[0104] In step 3013A, a first conversion relationship and a second conversion relationship are determined based on the converted first loop equation and the converted second loop equation, respectively.

[0105] Here, in combination with the converted first loop equation and the converted second loop equation, the first conversion relationship between the filtered phase line voltage and the phase line voltage before filtering and the filtered phase current is determined, and the second conversion relationship between the phase current before filtering and the phase line voltage before filtering and the filtered phase current is determined.

[0106] In an embodiment of the present application, for a balanced filtering circuit, when the inductance values ​​of the three phases in the first loop equation are the same, the first loop equation is converted; when the capacitance values ​​of the three phases in the second loop equation are the same, the second loop equation is converted; based on the converted first loop equation and the converted second loop equation, it is convenient to subsequently determine the first conversion relationship and the second conversion relationship, respectively.

[0107] In some embodiments, the loop equation includes a first loop equation and a second loop equation, the first loop equation includes the inductance values ​​of the three phases, and the second loop equation includes the capacitance values ​​of the three phases, see Figure 3C , Figure 3C This is a third flow chart of the modeling method of the filter circuit provided in an embodiment of the present application. Figure 3A Step 301 shown may be performed by Figure 3C Steps 3011B to 3013B are implemented as described in detail below.

[0108] In step 3011B, when the inductance values ​​of the three phases are different, the first loop equation is transformed to obtain a transformed first loop equation.

[0109] Here, when the inductance values ​​of the three phases in the first loop equation are different, the first loop equation is established according to Kirchhoff's voltage law, and the first loop equation is subjected to a matrix row-column conversion to obtain the converted first loop equation. The converted first loop equation is used to characterize the conversion relationship between the phase current before filtering and the phase line voltage before filtering and the phase line voltage after filtering. It should be noted that the difference between step 3011B and step 3011A is that step 3011B is to establish the first loop equation based on an unbalanced filter circuit, and the inductance values ​​of the three phases in the first loop equation are different. Step 3011A is to establish the first loop equation based on a balanced filter circuit, and the inductance values ​​of the three phases in the first loop equation are the same.

[0110] In step 3012B, when the capacitance values ​​of the three phases are different, the second loop equation is transformed to obtain a transformed second loop equation.

[0111] Here, when the capacitance values ​​of the three phases in the second loop equation are different, the second loop equation is established according to Kirchhoff's current law, and the second loop equation is subjected to a matrix row-column conversion to obtain the converted second loop equation. The converted second loop equation is used to characterize the conversion relationship between the phase line voltage after filtering and the phase current before filtering and the phase current after filtering. It should be noted that the difference between step 3012B and step 3012A is that step 3012B is based on an unbalanced filtering circuit to establish the second loop equation, and the capacitance values ​​of the three phases in the second loop equation are different. Step 3012A is based on a balanced filtering circuit to establish the second loop equation, and the capacitance values ​​of the three phases in the second loop equation are the same.

[0112] In step 3013B, based on the converted first loop equation and the converted second loop equation, a first conversion relationship and a second conversion relationship are determined respectively.

[0113] Here, it should be noted that step 3013B is the same as step 3013A and will not be repeated here.

[0114] In an embodiment of the present application, for an unbalanced filter circuit, when the inductance values ​​of the three phases in the first loop equation are different, the first loop equation is converted; when the capacitance values ​​of the three phases in the second loop equation are different, the second loop equation is converted, and based on the converted first loop equation and the converted second loop equation, it is convenient to subsequently determine the first conversion relationship and the second conversion relationship respectively.

[0115] In some embodiments, the converted first-loop equation includes the first differential result of the phase current before filtering, and the converted second-loop equation includes the second differential result of the phase line voltage after filtering. The first conversion relationship and the second conversion relationship can be determined based on the converted first-loop equation and the converted second-loop equation, respectively, by executing the following steps: converting the first differential result in the converted first-loop equation into a differential operator to obtain a first operator conversion result; converting the second differential result in the converted second-loop equation into a differential operator to obtain a second operator conversion result; and determining the first conversion relationship and the second conversion relationship based on the first operator conversion result and the second operator conversion result.

[0116] Here, the first differential result is the differential result of the phase current before filtering, the second differential result is the differential result of the phase line voltage after filtering, and the differential operator is represented by Laplace transform s. The first differential result is subjected to Laplace transform s conversion processing to obtain the first operator conversion result. The second differential result is subjected to Laplace transform s conversion processing to obtain the second operator conversion result. Based on the first operator conversion result, the conversion relationship between the phase current before filtering and the phase line voltage before filtering and the phase line voltage after filtering can be obtained. Based on the second operator conversion result, the conversion relationship between the phase line voltage after filtering and the phase current before filtering and the phase current after filtering can be obtained. Combined with the first operator conversion result and the second operator conversion result, the first conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering and the phase current after filtering is determined, and the second conversion relationship between the phase current before filtering and the phase line voltage before filtering and the phase current after filtering is determined.

[0117] For example, taking a balanced filter circuit as an example, the first differential result in formula (3) is converted into a differential operator to obtain a first operator conversion result, and the first operator conversion result is shown in formula (7):

[0118]

[0119] Among them, i a 、i b , i c represents the three phase currents before filtering, s represents the differential operator, L represents the inductance values ​​of the three phases, u ab、u bc Represents the two phase line voltages before filtering, u AB 、u BC Represents the two phase line voltages after filtering.

[0120] The second differential result in formula (6) is converted into a differential operator to obtain a second operator conversion result, and the second operator conversion result is shown in formula (8):

[0121]

[0122] Among them, u AB 、u BC 、u CA represents the three phase line voltages after filtering, s represents the differential operator, C represents the capacitance values ​​of the three phases, i a 、i b represents the two phase currents before filtering, i A 、i B Represents the two phase currents after filtering.

[0123] Combining formula (7) and formula (8), the first conversion relationship is shown in formula (9):

[0124]

[0125] Among them, u AB 、u BC 、u CA represents the three phase line voltages after filtering, L represents the inductance value of the three phases, C represents the capacitance value of the three phases, s represents the differential operator, u ab 、u bc 、u ca represents the three phase line voltages before filtering, i A 、i B 、i C Represents the three phase currents after filtering.

[0126] Combining formula (7) and formula (8), the second conversion relationship is shown in formula (10):

[0127]

[0128] Among them, i a 、i b 、i c represents the three phase currents before filtering, L represents the inductance value of the three phases, C represents the capacitance value of the three phases, s represents the differential operator, i A 、i B 、i C represents the three phase currents after filtering, u ab 、u bc、u ca Represents the three phase line voltages before filtering.

[0129] In an embodiment of the present application, the first differential result in the converted first-loop equation is converted into a differential operator to obtain a first operator conversion result, and the second differential result in the converted second-loop equation is converted into a differential operator to obtain a second operator conversion result. Based on the first operator conversion result and the second operator conversion result, the efficiency of determining the first conversion relationship and the second conversion relationship can be improved.

[0130] Continue to refer Figure 3A In step 302, based on the first conversion relationship, a connection relationship between a plurality of first logic operation units and the first logic operation units included in the voltage module is determined.

[0131] Here, the first logic operation unit refers to a plurality of logic operation units in the voltage module, and the first logic operation unit includes an addition logic operation unit, a subtraction logic operation unit, a multiplication logic operation unit, and a time delay logic operation unit.

[0132] In some embodiments, the first conversion relationship includes a first coefficient corresponding to the phase current after filtering, the first conversion relationship includes a second coefficient corresponding to the phase line voltage before filtering, and the voltage module includes a first voltage module and a second voltage module, see Figure 3D , Figure 3D This is a fourth flow chart of the modeling method for the filter circuit provided in an embodiment of the present application. Figure 3A Step 302 shown may be performed by Figure 3D Steps 3021 to 3025 are implemented as described in detail below.

[0133] In step 3021, based on the preset time constant and the differential operator, the dynamic characteristic coefficient is determined, and the differential operator is discretized to obtain a discrete differential operator.

[0134] Here, the dynamic characteristic coefficient is the coefficient related to the first-order inertia link, which describes a simple linear time-invariant system whose output signal responds to the input signal with the characteristics of a first-order differential equation. The dynamic characteristic coefficient is obtained by reciprocally transforming the product of the preset time constant and the differential operator. The differential operator can be discretized using the discrete Z transform to obtain a discrete differential operator. The discrete Z transform is a mathematical transformation that converts a discrete time domain signal into the Z domain (complex frequency domain).

[0135] For example, based on the preset time constant τ and the differential operator s, the dynamic characteristic coefficient can be The preset time constant τ can be determined by formula (11):

[0136]

[0137] Among them, W n Expressed as L represents the inductance value and C represents the capacitance value.

[0138] The differential operators in formula (9) and formula (10) are discretized, and the discrete differential operators are shown in formula (12):

[0139]

[0140] Among them, s represents the differential operator, z -1 represents discrete Z transform, T s Represents the time constant.

[0141] In step 3022, the dynamic characteristic coefficient is multiplied by the first coefficient to obtain an updated first coefficient.

[0142] According to the first conversion relationship, a conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering and the phase current after filtering is obtained. The dynamic characteristic coefficient and the first coefficient corresponding to the phase current after filtering in the first conversion relationship are multiplied to obtain an updated first coefficient.

[0143] For example, taking the balanced filter circuit as an example, according to the first conversion relationship in formula (9), the conversion relationship between the phase line voltage after filtering, the phase line voltage before filtering, and the phase current after filtering can be obtained. The conversion relationship corresponding to the phase line voltage after filtering is shown in formula (13):

[0144]

[0145] Among them, u AB represents the phase line voltage after filtering, L represents the inductance value of the three phases, C represents the capacitance value of the three phases, s represents the differential operator, u ab represents the phase line voltage before filtering, i A 、i B Represents the two phase currents after filtering.

[0146] The dynamic characteristic coefficient and the filtered phase current i A 、i B The corresponding first coefficient Ls is multiplied to obtain the updated first coefficient:

[0147] In step 3023, based on the updated first coefficient and the discrete differential operator, a first logic operation result corresponding to the filtered phase current in the first conversion relationship is determined.

[0148] The differential operator in the updated first coefficient is replaced with a discrete differential operator to obtain the converted first coefficient, and the converted first coefficient is multiplied by the filtered phase current to obtain the first logical operation result. For example, the updated first coefficient is Combining formula (11) and formula (12), we can get The differential operator s in is replaced by a discrete differential operator The first coefficient after conversion is obtained, and the first coefficient after conversion can be determined by formula (14):

[0149]

[0150] in, represents the first coefficient after conversion, L represents the inductance value of the three phases, s represents the differential operator, τ represents the preset time constant, W n Expressed as z -1 represents discrete Z transform, T s Represents the time constant.

[0151] The converted first coefficient is multiplied by the filtered phase current to obtain a first logic operation result, which can be determined by formula (15):

[0152]

[0153] Among them, u out1 Represents the first logical operation result, represents the first coefficient after conversion, L represents the inductance value of the three phases, W n Expressed as z -1 represents discrete Z transform, T s represents the time constant, i A 、i B Represents the two phase currents after filtering.

[0154] In step 3024, based on the first logic operation result, a connection relationship between a plurality of first logic operation units and the first logic operation units included in the first voltage module is determined.

[0155] Here, the first voltage module is a voltage module with a dynamic characteristic coefficient added, and the formula of the first logic operation result is calculated to obtain the conversion relationship between the first logic operation result and the filtered phase current. According to the conversion relationship between the first logic operation result and the filtered phase current, the connection relationship between the multiple first logic operation units and the first logic operation units included in the first voltage module is determined. The first logic operation unit includes an addition logic operation unit, a subtraction logic operation unit, a multiplication logic operation unit, and a time delay logic operation unit.

[0156] For example, the formula (15) of the first logic operation result is deduced to obtain the conversion relationship between the first logic operation result and the filtered phase current as shown in formula (16):

[0157]

[0158] Among them, u out1 represents the first logical operation result, L represents the inductance value of the three phases, W n Expressed as z -1 represents discrete Z transform, T s represents the time constant, i A 、i B Represents the two phase currents after filtering.

[0159] According to the conversion relationship in formula (16), the connection relationship between the plurality of first logic operation units and the first logic operation units included in the first voltage module is determined. For example, refer to Figure 6 , Figure 6 6 is a schematic diagram of the operation logic of the first voltage module provided in the embodiment of the present application. The first voltage module includes a plurality of first logic operation units, and area 601 is 100W in formula (16). n L(i A -i B ), region 602 is the operation logic of formula (16) The operation logic.

[0160] In step 3025, based on the second coefficient and the first logic operation result, a connection relationship between the plurality of first logic operation units and the first logic operation unit included in the second voltage module is determined.

[0161] Here, the second voltage module is a voltage module with a damping coefficient added. Based on the second coefficient corresponding to the phase line voltage before filtering in the first conversion relationship and the first logic operation result, the connection relationship between the multiple first logic operation units and the first logic operation units included in the second voltage module is determined.

[0162] In an embodiment of the present application, an updated first coefficient is obtained by multiplying the dynamic characteristic coefficient by the first coefficient, and the first logical operation result corresponding to the filtered phase current in the first conversion relationship is determined based on the updated first coefficient and the discrete differential operator. Therefore, based on the first logical operation result, the connection relationship between the multiple first logical operation units and the first logical operation units included in the first voltage module can be determined, thereby improving the system stability of the first voltage module.

[0163] In some embodiments, the connection relationship between the multiple first logic operation units and the first logic operation unit included in the second voltage module can be determined based on the second coefficient and the first logic operation result by executing the following steps: based on the second coefficient and the first logic operation result, determine the first transfer function between the phase line voltage after filtering and the phase line voltage before filtering; use the damping coefficient to update the first transfer function to obtain a second-order damped second transfer function; based on the second transfer function and the discrete differential operator, determine the third conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering; based on the third conversion relationship, determine the connection relationship between the multiple first logic operation units included in the second voltage module and the first logic operation unit.

[0164] Here, based on the second coefficient corresponding to the phase line voltage before filtering in the first conversion relationship and the first logical operation result, the first transfer function between the phase line voltage after filtering and the phase line voltage before filtering is determined. The first transfer function is calculated to obtain the conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering, and the first transfer function is updated using the damping coefficient damp. The damping coefficient (damping factor) is the ratio between the load impedance and the system output impedance, which affects the control ability of the circuit or system to the signal. The damping coefficient can be set to a value between 0.1 and 0.2, and the damping coefficient is added to the first transfer function, and the first transfer function is constructed into a second-order damped second transfer function. The second transfer function can be used to describe a second-order system with damped oscillation characteristics.

[0165] The differential operator in the second transfer function is replaced by a discrete differential operator, and a third conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering is determined. According to the third conversion relationship, a connection relationship between multiple first logic operation units and the first logic operation units included in the second voltage module is determined.

[0166] For example, by combining formulas (13) to (15), the first transfer function between the phase line voltage after filtering and the phase line voltage before filtering can be determined by formula (17):

[0167]

[0168] in, represents the second coefficient, u AB represents the phase line voltage after filtering, u ab Indicates the phase line voltage before filtering, u out1 represents the first logic operation result, L represents the inductance value of the three phases, C represents the capacitance value of the three phases, and s represents the differential operator.

[0169] By calculating the first transfer function, the conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering can be determined by formula (18):

[0170]

[0171] Among them, u AB represents the phase line voltage after filtering, u ab Indicates the phase line voltage before filtering, u out1 Represents the first logical operation result, W n Expressed as s represents a differential operator.

[0172] Add the damping coefficient to formula (18), and construct formula (18) into a second-order damped second transfer function. The second transfer function can be determined by formula (19):

[0173]

[0174] Among them, u AB represents the phase line voltage after filtering, u ab Indicates the phase line voltage before filtering, u out1 Represents the first logical operation result, W n Expressed as s represents the differential operator, and damp represents the damping coefficient.

[0175] Replace the differential operator s in the second transfer function with a discrete differential operator The third conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering can be determined by formula (20):

[0176]

[0177] Among them, u AB represents the phase line voltage after filtering, u ab Indicates the phase line voltage before filtering, u out1 Indicates the result of the first logical operation, u out2 Represents the first intermediate logic operation result, W n Expressed as damp represents the damping coefficient, T s represents the time constant, z -1 Represents discrete Z transform.

[0178] The first intermediate logic operation result can be determined by formula (21):

[0179]

[0180] Among them, u ABrepresents the phase line voltage after filtering, u ab Indicates the phase line voltage before filtering, u out1 Indicates the result of the first logical operation, u out2 Represents the first intermediate logic operation result, W n Expressed as damp represents the damping coefficient, T s represents the time constant, z -1 Represents discrete Z transform.

[0181] According to the conversion relationship in formula (20) and formula (21), the connection relationship between the plurality of first logic operation units and the first logic operation units included in the second voltage module is determined. Figure 7 , Figure 7 The second voltage module includes a plurality of first logic operation units, and area 701 is a first intermediate logic operation result u out2 The corresponding operation logic.

[0182] In an embodiment of the present application, a first transfer function between the phase line voltage after filtering and the phase line voltage before filtering is determined by using a second coefficient and a first logic operation result, and the first transfer function is updated using a damping coefficient to obtain a second-order damped second transfer function. Based on the second transfer function and a discrete differential operator, a third conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering is determined. Based on the third conversion relationship, the connection relationship between the multiple first logic operation units and the first logic operation unit included in the second voltage module can be determined, thereby improving the system stability of the second voltage module.

[0183] Continue to refer Figure 3A In step 303, based on the second conversion relationship, a connection relationship between the plurality of second logic operation units and the second logic operation units included in the current module is determined.

[0184] Here, the second logic operation unit refers to a plurality of logic operation units in the current module, and the second logic operation unit includes an addition logic operation unit, a subtraction logic operation unit, a multiplication logic operation unit, and a time delay logic operation unit.

[0185] In some embodiments, the second conversion relationship includes a third coefficient corresponding to the phase line voltage before filtering, the second conversion relationship includes a fourth coefficient corresponding to the phase current after filtering, and the current module includes a first current module and a second current module, see Figure 3E , Figure 3E This is the fifth flow chart of the modeling method of the filter circuit provided in the embodiment of the present application. Figure 3A Step 303 shown may be performed by Figure 3ESteps 3031 to 3035 are implemented as described in detail below.

[0186] In step 3031, based on a preset time constant and a differential operator, a dynamic characteristic coefficient is determined, and the differential operator is discretized to obtain a discrete differential operator.

[0187] Here, it should be noted that step 3031 is the same as step 3021 and will not be repeated here.

[0188] In step 3032, the dynamic characteristic coefficient is multiplied by the third coefficient to obtain an updated third coefficient.

[0189] According to the second conversion relationship, the conversion relationship between the phase current before filtering, the phase line voltage before filtering, and the phase current after filtering is obtained. The dynamic characteristic coefficient and the third coefficient corresponding to the phase line voltage before filtering in the second conversion relationship are multiplied to obtain an updated third coefficient.

[0190] For example, taking the balanced filter circuit as an example, the conversion relationship between the phase current before filtering, the phase current after filtering, and the phase line voltage before filtering can be obtained according to the second conversion relationship in formula (10). The conversion relationship corresponding to the phase current before filtering is shown in formula (22):

[0191]

[0192] Among them, i a represents the phase current before filtering, i A represents the phase current after filtering, C represents the capacitance value of the three phases, s represents the differential operator, u ab 、u ca Represents the two phase line voltages before filtering.

[0193] The dynamic characteristic coefficient and the phase line voltage u before filtering ab 、u ca The corresponding third coefficient Cs is multiplied to obtain the updated third coefficient:

[0194] In step 3033, based on the updated third coefficient and the discrete differential operator, a second logic operation result corresponding to the phase line voltage before filtering in the second conversion relationship is determined.

[0195] The differential operator in the updated third coefficient is replaced with a discrete differential operator to obtain the converted third coefficient, and the converted third coefficient is multiplied by the phase line voltage before filtering to obtain the second logical operation result. For example, the updated first coefficient is Combining formula (11) and formula (12), we can get The differential operator s in is replaced by a discrete differential operator The converted third coefficient can be determined by formula (23):

[0196]

[0197] in, represents the third coefficient after conversion, C represents the capacitance value of the three phases, s represents the differential operator, τ represents the preset time constant, W n Expressed as z -1 represents discrete Z transform, T s Represents the time constant.

[0198] The converted third coefficient is multiplied by the phase line voltage before filtering to obtain the second logic operation result, which can be determined by formula (24):

[0199]

[0200] Among them, i out1 Represents the second logical operation result, represents the third coefficient after conversion, C represents the capacitance value of the three phases, W n Expressed as z -1 represents discrete Z transform, T s represents the time constant, u ab 、u ca Represents the two phase line voltages before filtering.

[0201] In step 3034, based on the second logic operation result, a connection relationship between the plurality of second logic operation units and the second logic operation units included in the first current module is determined.

[0202] Here, the first current module is a current module with a dynamic characteristic coefficient added, and the formula of the second logic operation result is calculated to obtain the conversion relationship between the second logic operation result and the phase line voltage before filtering. According to the conversion relationship between the second logic operation result and the phase line voltage before filtering, the connection relationship between the multiple second logic operation units included in the first current module and the second logic operation unit is determined. The second logic operation unit includes an addition logic operation unit, a subtraction logic operation unit, a multiplication logic operation unit, and a time delay logic operation unit.

[0203] For example, the second logic operation result of formula (24) is calculated to obtain the conversion relationship between the second logic operation result and the phase line voltage before filtering as shown in formula (25):

[0204]

[0205] Among them, i out1 represents the result of the second logic operation, C represents the capacitance value of the three phases, W n Expressed as z -1 represents discrete Z transform, T s represents the time constant, u ab 、u ca Represents the two phase line voltages before filtering.

[0206] According to the conversion relationship in formula (25), the connection relationship between the plurality of second logic operation units included in the first current module and the second logic operation unit is determined. Fig. 9 , Fig. 9 is the output variable i provided in the embodiment of the present application a The current module operation logic diagram is shown in FIG. 901. Area 901 is the 100W in formula (25). n C(u ab -u ca ), area 902 is the operation logic of formula (25) The operation logic.

[0207] In step 3035, based on the fourth coefficient and the second logic operation result, a connection relationship between a plurality of second logic operation units included in the second current module and the second logic operation unit is determined.

[0208] Here, the second current module is a current module with a damping coefficient added. Based on the fourth coefficient corresponding to the filtered phase current in the second conversion relationship and the second logic operation result, the connection relationship between the multiple second logic operation units and the second logic operation units included in the second current module is determined.

[0209] In an embodiment of the present application, by multiplying the dynamic characteristic coefficient with the third coefficient to obtain an updated third coefficient, the second logic operation result corresponding to the phase line voltage before filtering in the second conversion relationship is determined based on the updated third coefficient and the discrete differential operator. Therefore, based on the second logic operation result, the connection relationship between the multiple second logic operation units included in the first current module and the second logic operation units can be determined, thereby improving the system stability of the first current module.

[0210] In some embodiments, the connection relationship between multiple second logic operation units and second logic operation units included in the second current module can be determined based on the fourth coefficient and the second logic operation result by executing the following steps: based on the fourth coefficient and the second logic operation result, determine the third transfer function between the phase current before filtering and the phase current after filtering; update the third transfer function using the damping coefficient to obtain a second-order fourth transfer function with damping; based on the fourth transfer function and the discrete differential operator, determine the fourth conversion relationship between the phase current before filtering and the phase current after filtering; based on the fourth conversion relationship, determine the connection relationship between multiple second logic operation units and second logic operation units included in the second current module.

[0211] Here, based on the fourth coefficient corresponding to the filtered phase current in the second conversion relationship and the second logical operation result, the third transfer function between the phase current before filtering and the phase current after filtering is determined. The third transfer function is calculated to obtain the conversion relationship between the phase current before filtering and the phase current after filtering, and the third transfer function is updated using the damping coefficient. The damping coefficient can be set to a value between 0.1 and 0.2, the damping coefficient is added to the third transfer function, and the third transfer function is constructed into a second-order damped fourth transfer function. The fourth transfer function can be used to describe a second-order system with damped oscillation characteristics.

[0212] The differential operator in the fourth transfer function is replaced with a discrete differential operator, a fourth conversion relationship between the phase current before filtering and the phase current after filtering is determined, and based on the fourth conversion relationship, a connection relationship between multiple second logic operation units included in the second current module and the second logic operation units is determined.

[0213] For example, by combining formulas (22) to (24), the third transfer function between the phase current before filtering and the phase current after filtering can be determined by formula (26):

[0214]

[0215] in, represents the fourth coefficient, i a represents the phase current before filtering, i A represents the phase current after filtering, i ou t1 represents the second logic operation result, L represents the inductance values ​​of the three phases, C represents the capacitance values ​​of the three phases, and s represents the differential operator.

[0216] By calculating the third transfer function, the conversion relationship between the phase current before filtering and the phase current after filtering can be determined by formula (27):

[0217]

[0218] Among them, i a represents the phase current before filtering, i A represents the phase current after filtering, i out1 Represents the result of the second logic operation, W n Expressed as s represents a differential operator.

[0219] Add the damping coefficient to formula (27), and construct formula (27) into a second-order damped fourth transfer function. The fourth transfer function can be determined by formula (28):

[0220]

[0221] Among them, i a represents the phase current before filtering, i A represents the phase current after filtering, i out1 Represents the result of the second logic operation, W n Expressed as s represents the differential operator, and damp represents the damping coefficient.

[0222] Replace the differential operator s in the fourth transfer function with a discrete differential operator The fourth conversion relationship between the phase current before filtering and the phase current after filtering can be determined by formula (29):

[0223]

[0224] Among them, i a represents the phase current before filtering, i A represents the phase current after filtering, i out1 Indicates the result of the second logical operation, i out2 Represents the second intermediate logic operation result, W n Expressed as damp represents the damping coefficient, T s represents the time constant, z -1 Represents discrete Z transform.

[0225] The second intermediate logic operation result can be determined by formula (30):

[0226]

[0227] Among them, i a represents the phase current before filtering, i A represents the phase current after filtering, i out1 Indicates the result of the second logical operation, i out2 Represents the second intermediate logic operation result, Wn Expressed as damp represents the damping coefficient, T s represents the time constant, z -1 Represents discrete Z transform.

[0228] According to the conversion relationship in formula (29) and formula (30), the connection relationship between the plurality of second logic operation units included in the second current module and the second logic operation unit is determined. Fig. 9 , Fig. 9 is the output variable i provided in the embodiment of the present application a The current module operation logic diagram. Area 903 is the second intermediate logic operation result i in formula (30) out2 The corresponding operation logic.

[0229] In an embodiment of the present application, a third transfer function between the phase current before filtering and the phase current after filtering is determined by the fourth coefficient and the second logic operation result, and the third transfer function is updated using the damping coefficient to obtain a second-order fourth transfer function with damping. Based on the fourth transfer function and the discrete differential operator, a fourth conversion relationship between the phase current before filtering and the phase current after filtering is determined. Based on the fourth conversion relationship, the connection relationship between the multiple second logic operation units and the second logic operation units included in the second current module can be determined, thereby improving the system stability of the second current module.

[0230] Continue to refer Figure 3A In step 304, a simulation model of the filter circuit is constructed based on the connection relationship between the first logic operation units and the connection relationship between the second logic operation units.

[0231] Here, based on the connection relationship between the first logic operation units and the connection relationship between the second logic operation units, the Xilinx module library of the Matrix Laboratory simulation software (MATLAB) is used to construct a simulation model of the filter circuit.

[0232] In some embodiments, the voltage module includes voltage modules of three phases, and the current module includes current modules of three phases. The simulation model of the filter circuit can be constructed based on the connection relationship between the first logic operation units and the connection relationship between the second logic operation units by executing the following steps: constructing voltage modules of three phases based on the connection relationship between the first logic operation units; constructing current modules of three phases based on the connection relationship between the second logic operation units; constructing a simulation model of the filter circuit based on the voltage modules of three phases and the current modules of three phases.

[0233] Here, based on the connection relationship between the first voltage module and the first logic operation unit in the second voltage module, a voltage module of each phase is constructed. Based on the connection relationship between the first current module and the second logic operation unit in the second current module, a current module of each phase is constructed. The voltage modules of the three phases and the current modules of the three phases are packaged together to obtain a simulation model of the filter circuit.

[0234] For example, the filtered phase line voltage u AB As an example, based on the connection relationship between the first voltage module and the first logic operation unit in the second voltage module, the filtered phase line voltage u is constructed. AB The voltage module. The phase current before filtering i a As an example, based on the connection relationship between the first current module and the second logic operation unit in the second current module, the phase current i before filtering is constructed. a Current module. Fig.10 , Fig.10 1001 and 1002. The voltage module 1001 includes the phase line voltage u after filtering. AB 、u BC 、u CA The voltage modules of the three phases, the current module 1002 includes the phase current i before filtering a 、i b 、i c Current module for three phases.

[0235] In an embodiment of the present application, a three-phase voltage module is constructed through the connection relationship between the first logic operation units, and a three-phase current module is constructed through the connection relationship between the second logic operation units. Therefore, based on the three-phase voltage module and the three-phase current module, a simulation model of the filter circuit can be completely constructed.

[0236] In some embodiments, after constructing a simulation model of the filtering circuit based on the connection relationship between the first logic operation units and the connection relationship between the second logic operation units, the following steps can be performed: obtaining a simulated filtering waveform of the simulation model, and comparing the simulated filtering waveform with the actual filtering waveform to obtain a verification result of the simulation model; when the verification result indicates that the simulated filtering waveform is different from the actual filtering waveform, re-obtaining the loop equation of the filtering circuit, and constructing a simulation model of the filtering circuit based on the re-obtained loop equation.

[0237] Here, the simulation model is applied to a certain power conversion system for simulation test, and after multiple online real-time simulation tests, a simulated filtering waveform is obtained. The simulated filtering waveform is compared with the actual filtering waveform to obtain the verification result of the simulation model. When the verification result indicates that the simulated filtering waveform is different from the actual filtering waveform, the filtering circuit principle is re-analyzed to re-obtain the first loop equation and the second loop equation of the filtering circuit. The re-obtained first loop equation and the second loop equation are converted, and based on the re-converted first loop equation and the second loop equation, the first conversion relationship and the second conversion relationship are re-determined to construct a simulation model of the filtering circuit.

[0238] In an embodiment of the present application, when the verification result of the simulation model indicates that the simulated filtering waveform is different from the actual filtering waveform, the loop equation of the filtering circuit is re-acquired, and a simulation model of the filtering circuit is constructed based on the re-acquired loop equation, thereby improving the modeling accuracy of the filtering circuit.

[0239] In some embodiments, the modeling method of the filter circuit provided in the embodiment of the present application can be applied in the field of intelligent modeling. Based on the loop equation of the filter circuit, the server determines the first conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering and the phase current after filtering, and determines the second conversion relationship between the phase current before filtering and the phase line voltage before filtering and the phase current after filtering. Based on the first conversion relationship, the connection relationship between the multiple first logic operation units and the first logic operation unit included in the voltage module is determined. Based on the second conversion relationship, the connection relationship between the multiple second logic operation units and the second logic operation unit included in the current module is determined. Based on the connection relationship between the first logic operation units and the connection relationship between the second logic operation units, the simulation model of the filter circuit is constructed. In this way, the server determines the conversion relationship between the phase line voltage before filtering, the phase line voltage after filtering, the phase current before filtering, and the phase current after filtering based on the loop equation of the filter circuit, thereby determining the connection relationship between the multiple logic operation units and the logic operation units included in the voltage module and the current module of the simulation model based on the conversion relationship, avoiding the direct construction of the simulation model based on the circuit connection structure of the filter circuit, and improving the modeling accuracy of the filter circuit.

[0240] The following describes an exemplary application of the filter circuit modeling method provided in an embodiment of the present application in an online simulation scenario of an AC three-phase inductor-capacitor LC filter circuit.

[0241] The physical test of the converter has the disadvantages of high risk, high device cost and long development cycle. It is necessary to establish a simulation model and conduct real-time online semi-physical simulation test verification on the simulation model, thereby effectively shortening the product development cycle and improving product development efficiency. The current modeling method of the AC three-phase LC filter circuit usually uses the component modules in the Simscape Electrical module library of the MATLAB simulation software or the Specialized Power System module library to build a simulation model of the AC three-phase LC filter circuit.

[0242] In the process of modeling the simulation model, the related technology has the following problems:

[0243] The component modules of the simulation model are packaged and cannot be modified a second time. When the simulation model is simulated in real time in the CPU hardware unit, the simulation accuracy is poor, and the model in the module library cannot be downloaded to the FPGA board hardware for high-precision real-time online simulation test verification, which makes it impossible to guarantee the product development cycle.

[0244] In view of the problems existing in the related art, the embodiment of the present application proposes a modeling method for a filter circuit, which includes the following improvements compared with the related art:

[0245] (1) Based on the analysis of the principle of AC three-phase LC filtering circuit, the loop equation is established and calculated. According to the calculated results of the loop equation, a simulation model is built. In the process of building the simulation model, the dynamic characteristic coefficient related to the first-order inertia link is added to improve the system stability. The damping coefficient is added to the simulation model to avoid resonance of the simulation model.

[0246] (2) Using the Xilinx module library of MATLAB simulation software, a simulation model of the AC three-phase LC balanced filter circuit and a simulation model of the AC three-phase LC unbalanced filter circuit are built, which supports online modification of the capacitor or inductor in the filter circuit.

[0247] Example, reference Figure 4 , Figure 4 Schematic diagram of the modeling process of the AC three-phase LC filter circuit simulation model provided in the embodiment of the present application. Figure 4 The flow chart in the figure explains the modeling method of the filter circuit provided in the embodiment of the present application.

[0248] In step 401, the principle of the AC three-phase LC filter circuit is analyzed and the loop equation is calculated.

[0249] Based on the analysis of the principle of AC three-phase LC filter circuit, the loop equation is established and calculated. The basic structures of AC three-phase LC filter circuit mainly include Y-type structure and triangle structure. Taking the AC three-phase LC filter circuit with triangle structure as an example, the reference Figure 5 , Figure 5 : is a schematic diagram of an AC three-phase LC balanced filter circuit provided in an embodiment of the present application. The phase current on phase line A is i a , the phase current on phase line B is i b , the phase current on phase line C is i c , phase current i a , phase current i b , phase current i c are the phase currents before filtering, and the phase current i A , phase current i B , phase current i C The phase currents are filtered. The phase voltage between phase lines A and B is u ab , the phase line voltage between phase lines B and C is u bc , the phase line voltage between phase lines C and A is u ca , phase line voltage u ab , phase line voltage u bc , phase line voltage u ca are the phase line voltages before filtering, and the phase line voltage u AB , phase line voltage u BC , phase line voltage u CA Both are phase line voltages after filtering. a , L b , L c is the single-phase filter inductance value, C ab , C bc , C ca It is the filtering single-phase capacitance value (this is a triangle connection method, the single-phase capacitance value of the triangle connection is 1 / 3 of the single-phase capacitance value of the Y-type connection).

[0250] The AC three-phase LC filter circuit includes loop 501, loop 502 and loop 503. For example, loop 501, loop 502 and loop 503 can be combined to establish a first loop equation and a second loop equation. The first loop equation is shown in formula (1):

[0251]

[0252] Among them, u ab 、u bc 、u ca represents the three phase line voltages before filtering, u AB 、u BC 、u CA Represents the three phase line voltages after filtering, La , L b , L c Indicates the inductance values ​​of the three phases, Represents the differential result of the three phase currents before filtering.

[0253] The first loop equation is transformed into a matrix with rows and columns. The result of the matrix transformation is shown in formula (2):

[0254]

[0255] Among them, L a , L b , L c Indicates the inductance values ​​of the three phases, represents the differential result of the three phase currents before filtering, u ab 、u bc 、u ca represents the three phase line voltages before filtering, u AB 、u BC 、u CA Represents the three phase line voltages after filtering.

[0256] The inductance values ​​L of the three phases in the first loop equation are a , L b , L c , converted to the same inductance value L, and the converted first loop equation is obtained. The converted first loop equation is shown in formula (3):

[0257]

[0258] in, represents the differential result of the three phase currents before filtering, L represents the inductance value of the three phases, u ab 、u bc Represents the two phase line voltages before filtering, u AB 、u BC Represents the two phase line voltages after filtering.

[0259] The second loop equation is shown in formula (4):

[0260]

[0261] Among them, i a 、i b 、i c represents the three phase currents before filtering, i A 、i B 、i C Represents the three phase currents after filtering, C ab , C bc , C caRepresents the capacitance values ​​of the three phases, It represents the differential result of the three phase line voltages after filtering.

[0262] The second loop equation is transformed into a matrix with rows and columns. The result of the matrix transformation is shown in formula (5):

[0263]

[0264] Among them, C ab , C bc , C ca Represents the capacitance values ​​of the three phases, Represents the differential result of the three phase line voltages after filtering, i a 、i b 、i c represents the three phase currents before filtering, i A 、i B , i C represents the three phase currents after filtering.

[0265] The capacitance values ​​C of the three phases in the second loop equation are ab , C bc , C ca , converted to the same capacitance value C, and the converted second loop equation is obtained. The converted second loop equation is shown in formula (6):

[0266]

[0267] in, represents the differential result of the three phase line voltages after filtering, C represents the capacitance value of the three phases, i a 、i b represents the two phase currents before filtering, i A 、i B Represents the two phase currents after filtering.

[0268] The first differential result in formula (3) is converted by Laplace transform s (differential operator s), and the first operator conversion result is shown in formula (7):

[0269]

[0270] Among them, i a 、i b 、i c represents the three phase currents before filtering, s represents the differential operator, L represents the inductance values ​​of the three phases, and u ab 、u bc Represents the two phase line voltages before filtering, u AB 、u BC Represents the two phase line voltages after filtering.

[0271] The second differential result in formula (6) is transformed by Laplace transform s, and the second operator transformation result is shown in formula (8):

[0272]

[0273] Among them, u AB 、u BC 、u CA represents the three phase line voltages after filtering, s represents the differential operator, C represents the capacitance values ​​of the three phases, i a 、i b represents the two phase currents before filtering, i A 、i B Represents the two phase currents after filtering.

[0274] Combining formula (7) and formula (8), the first conversion relationship between the phase line voltage after filtering, the phase line voltage before filtering, and the phase current after filtering is shown in formula (9):

[0275]

[0276] Among them, u AB 、u BC 、u CA represents the three phase line voltages after filtering, L represents the inductance value of the three phases, C represents the capacitance value of the three phases, s represents the differential operator, u ab 、u bc 、u ca represents the three phase line voltages before filtering, i A 、i B 、i C Represents the three phase currents after filtering.

[0277] Combining formula (7) and formula (8), the second conversion relationship between the phase current before filtering, the phase line voltage before filtering, and the phase current after filtering is shown in formula (10):

[0278]

[0279] Among them, i a 、i b 、i c represents the three phase currents before filtering, L represents the inductance value of the three phases, C represents the capacitance value of the three phases, s represents the differential operator, i A 、i B 、i C represents the three phase currents after filtering, u ab 、u bc 、u ca Represents the three phase line voltages before filtering.

[0280] Continue to refer Figure 4 In step 402, a simulation model is built according to the calculation results of the loop equation.

[0281] According to the first conversion relationship in formula (9) and the second conversion relationship in formula (10), the simulation model is built using the Xilinx module library of MATLAB simulation software.

[0282] In step 403, inertia elements and damping coefficients are added during the construction of the simulation model.

[0283] In the process of building the simulation model, in order to improve the stability of the simulation model system, a first-order inertia link is added to the voltage module and current module of the simulation model. The dynamic characteristic coefficient related to the first-order inertia link is The preset time constant τ can be determined by formula (11):

[0284]

[0285] Among them, W n Expressed as L represents the inductance value and C represents the capacitance value.

[0286] In the process of building the simulation model, the differential operators in formula (9) and formula (10) are discretized, and the discrete differential operators are shown in formula (12):

[0287]

[0288] Among them, s represents the differential operator, z -1 represents discrete Z transform, T s Represents the time constant.

[0289] The output variable is u AB Taking the voltage module operation logic as an example, according to the first conversion relationship in formula (9), we can get u AB The corresponding conversion relationship, u AB The corresponding conversion relationship is shown in formula (13):

[0290]

[0291] Among them, u AB represents the phase line voltage after filtering, L represents the inductance value of the three phases, C represents the capacitance value of the three phases, s represents the differential operator, u ab represents the phase line voltage before filtering, i A 、i B Represents the two phase currents after filtering.

[0292] The filtered phase current i A 、i B The corresponding first coefficient Ls and the dynamic characteristic coefficient related to the first-order inertia link are multiplied to obtain the updated first coefficient: Combining formula (11) and formula (12), the first coefficient after conversion can be determined by formula (14):

[0293]

[0294] in, represents the first coefficient after conversion, L represents the inductance value of the three phases, s represents the differential operator, τ represents the preset time constant, W n Expressed as z -1 represents discrete Z transform, T s Represents the time constant.

[0295] The converted first coefficient is multiplied by the filtered phase current to obtain a first logic operation result, which can be determined by formula (15):

[0296]

[0297] Among them, u out1 Represents the first logical operation result, represents the first coefficient after conversion, L represents the inductance value of the three phases, W n Expressed as z -1 represents discrete Z transform, T s represents the time constant, i A 、i B Represents the two phase currents after filtering.

[0298] By calculating formula (15), the conversion relationship between the first logic operation result and the filtered phase current is shown in formula (16):

[0299]

[0300] Among them, u out1 represents the first logical operation result, L represents the inductance value of the three phases, W n Expressed as z -1 represents discrete Z transform, T s represents the time constant, i A 、i B Represents the two phase currents after filtering.

[0301] According to the conversion relationship in formula (16), the output variable u is constructed ABThe first voltage module. For example, refer to Figure 6 , Figure 6 6 is a schematic diagram of the operation logic of the first voltage module provided in the embodiment of the present application. The first voltage module includes a plurality of first logic operation units, and area 601 is 100W in formula (16). n L(i A -i B ), region 602 is the operation logic of formula (16) The operation logic of the first current module is the same as the operation logic of the first voltage module, which will not be repeated here.

[0302] In order to avoid resonance in the simulation model, a damping coefficient is added to the voltage module and current module of the simulation model. The damping coefficient can be set to a value between 0.1 and 0.2. Combining formulas (13) to (15), the output variable u is obtained. AB The phase line voltage u before filtering ab The first transfer function between can be determined by formula (17):

[0303]

[0304] in, represents the second coefficient, u out1 represents the first logic operation result, L represents the inductance value of the three phases, C represents the capacitance value of the three phases, and s represents the differential operator.

[0305] By calculating the first transfer function, the conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering can be determined by formula (18):

[0306]

[0307] Among them, u AB represents the phase line voltage after filtering, u ab Indicates the phase line voltage before filtering, u out1 Represents the result of the first logical operation, and W is represented by s represents a differential operator.

[0308] Add the damping coefficient to formula (18), and construct formula (18) into a second-order damped second transfer function. The second transfer function can be determined by formula (19):

[0309]

[0310] Among them, u AB represents the phase line voltage after filtering, u ab Indicates the phase line voltage before filtering, u out1Represents the result of the first logical operation, and W is represented by s represents the differential operator, and damp represents the damping coefficient.

[0311] Replace the differential operator s in the second transfer function with a discrete differential operator The third conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering can be determined by formula (20):

[0312]

[0313] Among them, u AB represents the phase line voltage after filtering, u ab Indicates the phase line voltage before filtering, u out1 Indicates the result of the first logical operation, u out2 Represents the first intermediate logic operation result, W n Expressed as damp represents the damping coefficient, T s represents the time constant, z -1 Represents discrete Z transform.

[0314] The first intermediate logic operation result can be determined by formula (21):

[0315]

[0316] Among them, u AB represents the phase line voltage after filtering, u ab Indicates the phase line voltage before filtering, u out1 Indicates the result of the first logical operation, u out2 Represents the first intermediate logic operation result, W n Expressed as damp represents the damping coefficient, T s represents the time constant, z -1 Represents discrete Z transform.

[0317] According to the conversion relationship in formula (20) and formula (21), the output variable u is constructed AB The second voltage module. For example, refer to Figure 7 , Figure 7 The second voltage module includes a plurality of first logic operation units, and area 701 is a first intermediate logic operation result u out2 The corresponding operation logic: The operation logic of the second current module is the same as that of the second voltage module, and will not be repeated here.

[0318] Continue to refer Figure 4 , in step 404, the construction of the simulation model is completed.

[0319] The first voltage module operation logic and the second voltage module operation logic are combined together to obtain a voltage module of an output variable of a phase. For example, refer to Figure 8 , Figure 8 is the output variable u provided in the embodiment of the present application AB Schematic diagram of the voltage module operation logic. Area 801 is the output variable u AB The first voltage module operation logic, region 802 is the output variable u AB The second voltage module operation logic. Output variable u BC 、u CA The voltage module operation logic and output variable u AB The voltage module operation logic is the same as that of FIG. 1 and will not be repeated here.

[0320] Example, reference Fig. 9 , Fig. 9 is the output variable i provided in the embodiment of the present application a The current module operation logic diagram is shown in FIG. 901. Area 901 is the 100W in formula (25). n C(u ab -u ca ), area 902 is the operation logic of formula (25) The operation logic of the second intermediate logic operation result i in formula (30) is shown in FIG. out2 The corresponding operation logic. Output variable i b 、i c The current module operation logic and output variable i a The current module operation logic is the same as that of , and will not be repeated here.

[0321] The three-phase voltage module and the three-phase current module are encapsulated into a simulation model of an AC three-phase LC filter circuit. For example, refer to Fig.10 , Fig.10 1 is a schematic diagram of a simulation model of an AC three-phase LC filter circuit provided in an embodiment of the present application. The simulation model includes a voltage module 1001 and a current module 1002. The simulation model provided in an embodiment of the present application can be used in other circuits including an AC three-phase LC filter. The input variables and output variables of the simulation model are shown in Table 1:

[0322] Table 1

[0323]

[0324] The above simulation model is built on the basis of a balanced filtering circuit, that is, the inductance values ​​of the three phases are the same, and the capacitance values ​​of the three phases are the same. For the unbalanced filtering circuit (the inductance values ​​of the three phases are different, and the capacitance values ​​of the three phases are different), the loop equation calculation process and the simulation model construction process are the same as the above process.

[0325] For example, take the Y-type AC three-phase LC unbalanced filter circuit as an example, refer to Fig.11 , Fig.11 : is a schematic diagram of an AC three-phase LC unbalanced filter circuit provided in an embodiment of the present application. The phase current on phase line A is i a , the phase current on phase line B is i b , the phase current on phase line C is i c , phase current i a , phase current i b , phase current i c are the phase currents before filtering, and the phase current i A , phase current i B , phase current i C are all filtered phase currents. The phase voltage on phase line A is u a , the phase voltage on phase line B is u b , the phase voltage on phase line C is u c , phase voltage u a , phase voltage u b , phase voltage u c are the phase voltages before filtering, and the phase voltage u A , phase voltage u B , phase voltage u C Both are phase voltages after filtering. a , L b , L c is the single-phase filter inductance value, C a , C b , C c is the filtering single-phase capacitance value (based on the single-phase capacitance value C connected in a triangle ab , C bc , C ca Two sets of loop equations are established for the unbalanced filter circuit in Y-type connection mode, and the two sets of loop equations are deduced. The deduced results of the two sets of loop equations are shown in formula (31) and formula (32):

[0326]

[0327] Among them, u A 、u B 、u C Represents the three phase voltages after filtering, L a , L b , Lc Indicates the inductance values ​​of the three phases, C a , C b , C c represents the capacitance value of the three phases, s represents the differential operator, u a 、u b 、u c Represents the three phase voltages before filtering, i A 、i B 、i C Represents the three phase currents after filtering.

[0328]

[0329] Among them, i a 、i b 、i c Represents the three phase currents before filtering, L a , L b , L c Indicates the inductance values ​​of the three phases, C a , C b , C c represents the capacitance value of the three phases, s represents the differential operator, i A 、i B 、i C represents the three phase currents after filtering, u a 、u b 、u c Represents the three phase voltages before filtering.

[0330] According to the conversion relationship in formula (31) and formula (32), the device module in the Xilinx module library of MATLAB simulation software is used to build a simulation model of the AC three-phase LC unbalanced filter circuit. In the process of building the simulation model of the unbalanced filter circuit, in order to improve the stability of the simulation model system, the dynamic characteristic coefficient and the damping coefficient are added to the voltage module and the current module of the simulation model. The process of adding the dynamic characteristic coefficient and the damping coefficient is the same as that of the above-mentioned balanced filter circuit. For example, refer to Fig.12 , Fig.12 is the output variable u provided in the embodiment of the present application A Schematic diagram of the voltage module operation logic. Area 1201 is the output variable u A The first voltage module operation logic, region 1202 is the output variable u A The second voltage module operation logic. Output variable u B 、u C The voltage module operation logic and output variable u A The voltage module operation logic is the same as that of the , so it will not be repeated here. Fig.13 , Fig.13 is the output variable i of the unbalanced filter circuit provided in the embodiment of the present application a Schematic diagram of the current module operation logic. Region 1301 is the output variable i of the unbalanced filter circuit a The first current module operation logic, region 1302 is the output variable i of the unbalanced filter circuit a The second current module operation logic, the output variable i of the unbalanced filter circuit b 、i c The current module operation logic and the output variable i of the unbalanced filter circuit a The current module operation logic is the same as that of , and will not be repeated here.

[0331] The three-phase voltage modules and three-phase current modules of the unbalanced filter circuit are encapsulated as a simulation model of the AC three-phase LC unbalanced filter circuit. For example, refer to Fig.14 , Fig.14 The simulation model of the AC three-phase LC unbalanced filter circuit provided in the embodiment of the present application is a schematic diagram. The simulation model of the AC three-phase LC unbalanced filter circuit provided in the embodiment of the present application can be used in a filter circuit that needs to perform an AC three-phase LC unbalanced working condition.

[0332] Continue to refer Figure 4 , in step 405, the simulation model performs a real-time simulation test.

[0333] In step 406, the correctness of the simulation model is verified.

[0334] If the filtering result of the simulation model is verified to be incorrect, the process proceeds to step 401 to analyze the principle of the AC three-phase LC filtering circuit and deduce the loop equation; if the filtering result of the simulation model is verified to be correct, the process proceeds to step 407 to complete the construction of the simulation model.

[0335] Taking the AC three-phase LC balanced filter circuit with a triangle structure as an example, the simulation model of the AC three-phase LC balanced filter circuit is applied to a certain power conversion system for semi-physical simulation test verification to verify the correctness and accuracy of the simulation model and set the inductance value L of the three phases. a , L b , L c Both are 1.12e -3 H, capacitance values ​​C of the three phases ab , C bc , C ca All 3e -4 F, the damping coefficient is set to a value between 0.1 and 0.2, and the simulation step is 1e -7 s.

[0336] After multiple online real-time simulation tests, the real-time online operation waveforms of the input variables and output variables of the simulation model are obtained to verify the effectiveness of the modeling method. Fig.15 , Fig.15 : is a schematic diagram of the three-phase line voltage waveform before filtering provided in an embodiment of the present application. The three-phase line voltage waveform before filtering includes the phase line voltage u before filtering ab Waveform 1501, phase line voltage u before filtering bc Waveform 1502, phase line voltage u before filtering ca Waveform 1503. Example, reference Fig.16 , Fig.16 : is a schematic diagram of a three-phase current waveform after filtering provided in an embodiment of the present application. The three-phase current waveform after filtering includes the phase current i A Waveform 1601, filtered phase current i B Waveform 1602, filtered phase current u C Waveform 1603. Example, reference Fig.17 , Fig.17 : is a schematic diagram of a three-phase line voltage waveform after filtering provided by an embodiment of the present application. The three-phase line voltage waveform after filtering includes the phase line voltage u AB Waveform 1701, filtered phase line voltage u BC Waveform 1702, filtered phase line voltage u CA Waveform 1703. Example, reference Fig.18 , Fig.18 : is a schematic diagram of the three-phase current waveform before filtering provided in the embodiment of the present application. The three-phase current waveform before filtering includes the phase current i before filtering a Waveform 1801, phase current i before filtering b Waveform 1802, phase current i before filtering c Waveform 1803. The simulation model provided in the embodiment of the present application can also be applied to semi-physical simulation debugging tests such as high-frequency auxiliary systems and locomotive auxiliary systems. The system operation of the simulation model is stable and the filtering effect is obvious.

[0337] Taking the Y-type AC three-phase LC unbalanced filter circuit as an example, the simulation model of the AC three-phase LC unbalanced filter circuit is compared with the Specialized Power System model for simulation test verification, and the inductance values ​​L of the three phases are set. a , L b , L c All 3e -3 H, capacitance values ​​C of the three phases a 3e -5 F, C b 7.8e -5 F, C c7.8e -5 F. The simulation model of the AC three-phase LC unbalanced filter circuit provided in the embodiment of the present application supports online changes in the inductance values ​​of the three phases and the capacitance values ​​of the three phases to simulate the working condition test of the AC three-phase LC unbalanced filter circuit. The simulation model provided in the embodiment of the present application is kept consistent with the parameters and input variables in the Specialized Power System model, and a simulation comparison test is performed to verify and obtain the waveform of the simulation test result.

[0338] Example, reference Fig.19 , Fig.19 The solid line represents the output variable A phase voltage u of the Specialized Power System model. A The waveform is represented by a dotted line, which indicates the output variable of the simulation model provided by the present application, the phase voltage u of the A phase A By comparing the waveforms, it can be seen that the output variable A phase voltage waveform of the simulation model provided by the present application and the output variable A phase voltage waveform of the Specialized Power System model are highly consistent. Fig. 20 , Fig. 20 1 is a schematic diagram showing the comparison of the output variable A phase current waveform provided by the embodiment of the present application. The solid line represents the output variable A phase current i of the Specialized Power System model. a The waveform is represented by a dotted line, which indicates the output variable of the simulation model provided by the present application, the phase current i of the A phase a Waveform, through waveform comparison, it can be obtained that the output variable A phase current waveform of the simulation model provided in the present application and the output variable A phase current waveform of the Specialized Power System model are highly consistent.

[0339] Example, reference Fig.21 , Fig.21 The solid line represents the output variable B phase voltage u of the Specialized Power System model. B The waveform is represented by a dotted line, which indicates the output variable of the simulation model provided by the present application, the phase voltage u of the phase B B By comparing the waveforms, it can be seen that the output variable B phase voltage waveform of the simulation model provided by the present application and the output variable B phase voltage waveform of the Specialized Power System model are highly consistent. Fig. 22 , Fig. 221 is a schematic diagram showing the comparison of the output variable B-phase current waveform provided by the embodiment of the present application. The solid line represents the output variable B-phase current i of the Specialized Power System model. b The waveform is represented by a dotted line, which indicates the output variable of the simulation model provided by the present application, the phase current i of the phase B b Waveform, through waveform comparison, it can be obtained that the output variable B phase current waveform of the simulation model provided in the present application and the output variable B phase current waveform of the Specialized Power System model are highly consistent.

[0340] Example, reference Fig.23 , Fig.23 The solid line represents the output variable C phase voltage u of the Specialized Power System model. C The waveform is represented by a dotted line, which indicates the output variable of the simulation model provided by the present application, the phase voltage u of the C phase C By comparing the waveforms, it can be seen that the output variable C phase voltage waveform of the simulation model provided by the present application and the output variable C phase voltage waveform of the Specialized Power System model are highly consistent. Fig.24 , Fig.24 1 is a schematic diagram showing a comparison of the output variable C phase current waveform provided in the embodiment of the present application. The solid line represents the output variable C phase current i of the Specialized Power System model. c The waveform is represented by a dotted line, which indicates the output variable of the simulation model provided by the present application, the phase current i of the C phase c Waveform, through waveform comparison, it can be obtained that the output variable C-phase current waveform of the simulation model provided in the present application and the output variable C-phase current waveform of the Specialized Power System model are highly consistent.

[0341] In summary, by comparing the simulation model provided in the present application with the Specialized Power System model, it can be verified that the three-phase voltage waveform and the three-phase current waveform of the output variables are highly consistent, which verifies the effectiveness of the modeling method of the filter circuit provided in the embodiment of the present application.

[0342] In the above-mentioned application scenario of real-time online simulation of the AC three-phase LC filter circuit, according to the calculated results of the loop equation of the AC three-phase LC filter circuit, the Xilinx module library of the MATLAB simulation software is used to build a simulation model of the AC three-phase LC filter circuit, which can perform semi-physical real-time online simulation tests. The dynamic characteristic coefficient and damping coefficient are added to the simulation model to improve the stability of the simulation model system operation. The simulation model supports online changes in the inductance and capacitance values ​​of the three-phase filter, and can perform semi-physical simulation tests of the three-phase LC unbalanced filter circuit. The simulation model is encapsulated as a module, which can be applied to the online real-time simulation of other main circuits including the three-phase LC filter circuit, so as to realize the rapid construction of the simulation model.

[0343] The following continues to describe the exemplary structure of the filter circuit modeling device 455 provided in the embodiment of the present application implemented as a software module. In some embodiments, such as Figure 2 As shown, the software modules in the modeling device 455 of the filter circuit stored in the memory 450 may include: a first determination module 4551, which is used to determine the first conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering and the phase current after filtering based on the loop equation of the filter circuit, and determine the second conversion relationship between the phase current before filtering and the phase line voltage before filtering and the phase current after filtering; a second determination module 4552, which is used to determine the connection relationship between the multiple first logic operation units included in the voltage module and the first logic operation unit based on the first conversion relationship; a third determination module 4553, which is used to determine the connection relationship between the multiple second logic operation units and the second logic operation unit included in the current module based on the second conversion relationship; a model construction module 4554, which is used to construct a simulation model of the filter circuit based on the connection relationship between the first logic operation units and the connection relationship between the second logic operation units.

[0344] In some embodiments, the loop equation includes a first loop equation and a second loop equation, the first loop equation includes the inductance values ​​of the three phases, the second loop equation includes the capacitance values ​​of the three phases, and the first determination module 4551 is also used to convert the first loop equation when the inductance values ​​of the three phases are the same to obtain the converted first loop equation, and the converted first loop equation is used to characterize the conversion relationship between the phase current before filtering and the phase line voltage before filtering and the phase line voltage after filtering; when the capacitance values ​​of the three phases are the same, the second loop equation is converted to obtain the converted second loop equation, and the converted second loop equation is used to characterize the conversion relationship between the phase line voltage after filtering and the phase current before filtering and the phase current after filtering; based on the converted first loop equation and the converted second loop equation, the first conversion relationship and the second conversion relationship are determined respectively.

[0345] In some embodiments, the loop equation includes a first loop equation and a second loop equation, the first loop equation includes the inductance values ​​of the three phases, the second loop equation includes the capacitance values ​​of the three phases, and the first determination module 4551 is also used to convert the first loop equation when the inductance values ​​of the three phases are different, to obtain the converted first loop equation, and the converted first loop equation is used to characterize the conversion relationship between the phase current before filtering and the phase line voltage before filtering and the phase line voltage after filtering; when the capacitance values ​​of the three phases are different, the second loop equation is converted to obtain the converted second loop equation, and the converted second loop equation is used to characterize the conversion relationship between the phase line voltage after filtering and the phase current before filtering and the phase current after filtering; based on the converted first loop equation and the converted second loop equation, the first conversion relationship and the second conversion relationship are determined respectively.

[0346] In some embodiments, the converted first-loop equation includes a first differential result of the phase current before filtering, and the converted second-loop equation includes a second differential result of the phase line voltage after filtering. The first determination module 4551 is also used to convert the first differential result in the converted first-loop equation into a differential operator to obtain a first operator conversion result; convert the second differential result in the converted second-loop equation into a differential operator to obtain a second operator conversion result; and determine the first conversion relationship and the second conversion relationship based on the first operator conversion result and the second operator conversion result.

[0347] In some embodiments, the first conversion relationship includes a first coefficient corresponding to the phase current after filtering, the first conversion relationship includes a second coefficient corresponding to the phase line voltage before filtering, the voltage module includes a first voltage module and a second voltage module, and the second determination module 4552 is also used to determine the dynamic characteristic coefficient based on a preset time constant and a differential operator, and discretize the differential operator to obtain a discrete differential operator; multiply the dynamic characteristic coefficient by the first coefficient to obtain an updated first coefficient; based on the updated first coefficient and the discrete differential operator, determine the first logical operation result corresponding to the filtered phase current in the first conversion relationship; based on the first logical operation result, determine the connection relationship between the multiple first logical operation units included in the first voltage module and the first logical operation unit; based on the second coefficient and the first logical operation result, determine the connection relationship between the multiple first logical operation units included in the second voltage module and the first logical operation unit.

[0348] In some embodiments, the second determination module 4552 is also used to determine the first transfer function between the phase line voltage after filtering and the phase line voltage before filtering based on the second coefficient and the first logical operation result; update the first transfer function using the damping coefficient to obtain a second-order damped second transfer function; determine the third conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering based on the second transfer function and the discrete differential operator; based on the third conversion relationship, determine the connection relationship between the multiple first logical operation units included in the second voltage module and the first logical operation unit.

[0349] In some embodiments, the second conversion relationship includes a third coefficient corresponding to the phase line voltage before filtering, the second conversion relationship includes a fourth coefficient corresponding to the phase current after filtering, the current module includes a first current module and a second current module, and the third determination module 4553 is also used to determine the dynamic characteristic coefficient based on a preset time constant and a differential operator, and discretize the differential operator to obtain a discrete differential operator; multiply the dynamic characteristic coefficient by the third coefficient to obtain an updated third coefficient; based on the updated third coefficient and the discrete differential operator, determine the second logic operation result corresponding to the phase line voltage before filtering in the second conversion relationship; based on the second logic operation result, determine the connection relationship between the multiple second logic operation units and the second logic operation units included in the first current module; based on the fourth coefficient and the second logic operation result, determine the connection relationship between the multiple second logic operation units and the second logic operation units included in the second current module.

[0350] In some embodiments, the third determination module 4553 is also used to determine a third transfer function between the phase current before filtering and the phase current after filtering based on the fourth coefficient and the second logic operation result; update the third transfer function using the damping coefficient to obtain a second-order damped fourth transfer function; determine a fourth conversion relationship between the phase current before filtering and the phase current after filtering based on the fourth transfer function and a discrete differential operator; and determine a connection relationship between multiple second logic operation units and the second logic operation units included in the second current module based on the fourth conversion relationship.

[0351] In some embodiments, the voltage module includes a three-phase voltage module, the current module includes a three-phase current module, and the model construction module 4554 is also used to construct a three-phase voltage module based on the connection relationship between the first logic operation units; to construct a three-phase current module based on the connection relationship between the second logic operation units; and to construct a simulation model of the filter circuit based on the three-phase voltage modules and the three-phase current modules.

[0352] In some embodiments, the model construction module 4554 is also used to construct a simulation model of the filter circuit based on the connection relationship between the first logic operation units and the connection relationship between the second logic operation units, then obtain a simulated filtering waveform of the simulation model, and compare the simulated filtering waveform with the actual filtering waveform to obtain a verification result of the simulation model; when the verification result indicates that the simulated filtering waveform is different from the actual filtering waveform, re-obtain the loop equation of the filter circuit, and construct a simulation model of the filter circuit based on the re-obtained loop equation.

[0353] The embodiment of the present application provides a computer program product, which includes computer executable instructions or computer programs, and the computer executable instructions or computer programs are stored in a computer-readable storage medium. The processor of the electronic device reads the computer executable instructions or computer programs from the computer-readable storage medium, and the processor executes the computer executable instructions or computer programs, so that the electronic device performs the above-mentioned method of the embodiment of the present application.

[0354] The present application embodiment provides a computer-readable storage medium storing computer-executable instructions, wherein the computer-executable instructions or computer programs are stored. When the computer-executable instructions or computer programs are executed by a processor, the processor will be caused to execute the method provided by the present application embodiment, for example, Figure 3A The modeling method of the filter circuit is shown.

[0355] In some embodiments, the computer-readable storage medium may be a memory such as FRAM, ROM, PROM, EPROM, EEPROM, flash memory, magnetic surface storage, optical disk, or CD-ROM; or it may be various devices including one or any combination of the above memories.

[0356] In some embodiments, computer executable instructions may be in the form of a program, software, software module, script or code, written in any form of programming language (including compiled or interpreted languages, or declarative or procedural languages), and may be deployed in any form, including as a stand-alone program or as a module, component, subroutine or other unit suitable for use in a computing environment.

[0357] As an example, computer-executable instructions may, but need not, correspond to a file in a file system, may be stored as part of a file that stores other programs or data, such as in one or more scripts in a HyperText Markup Language (HTML) document, in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files storing one or more modules, subroutines, or code portions).

[0358] As an example, computer executable instructions may be deployed to be executed on one electronic device, or on multiple electronic devices located at one site, or on multiple electronic devices distributed at multiple sites and interconnected by a communication network.

[0359] The above is only an embodiment of the present application and is not intended to limit the protection scope of the present application. Any modifications, equivalent substitutions and improvements made within the spirit and scope of the present application are included in the protection scope of the present application.

Claims

1. A modeling method for a filter circuit, characterized in that: The method comprises: Based on the loop equation of the filtering circuit, determining a first conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering and the phase current after filtering, and determining a second conversion relationship between the phase current before filtering and the phase line voltage before filtering and the phase current after filtering; Based on the first conversion relationship, determining a connection relationship between a plurality of first logic operation units included in a voltage module and the first logic operation unit; Based on the second conversion relationship, determining a connection relationship between a plurality of second logic operation units included in the current module and the second logic operation unit; A simulation model of the filter circuit is constructed based on the connection relationship between the first logic operation units and the connection relationship between the second logic operation units.

2. The method according to claim 1, characterized in that The loop equation includes a first loop equation and a second loop equation, the first loop equation includes the inductance values ​​of the three phases, the second loop equation includes the capacitance values ​​of the three phases, the loop equation based on the filtering circuit determines the first conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering and the phase current after filtering, and determines the second conversion relationship between the phase current before filtering and the phase line voltage before filtering and the phase current after filtering, including: When the inductance values ​​of the three phases are the same, the first loop equation is converted to obtain a converted first loop equation, wherein the converted first loop equation is used to characterize a conversion relationship between the phase current before filtering and the phase line voltage before filtering and the phase line voltage after filtering; When the capacitance values ​​of the three phases are the same, the second loop equation is converted to obtain a converted second loop equation, wherein the converted second loop equation is used to characterize the conversion relationship between the phase line voltage after filtering and the phase current before filtering and the phase current after filtering; Based on the converted first loop equation and the converted second loop equation, the first conversion relationship and the second conversion relationship are determined respectively.

3. The method according to claim 1, characterized in that The loop equation includes a first loop equation and a second loop equation, the first loop equation includes the inductance values ​​of the three phases, the second loop equation includes the capacitance values ​​of the three phases, the loop equation based on the filtering circuit determines the first conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering and the phase current after filtering, and determines the second conversion relationship between the phase current before filtering and the phase line voltage before filtering and the phase current after filtering, including: In the case where the inductance values ​​of the three phases are different, the first loop equation is converted to obtain a converted first loop equation, wherein the converted first loop equation is used to characterize the conversion relationship between the phase current before filtering and the phase line voltage before filtering and the phase line voltage after filtering; In the case where the capacitance values ​​of the three phases are different, the second loop equation is converted to obtain a converted second loop equation, wherein the converted second loop equation is used to characterize the conversion relationship between the phase line voltage after filtering and the phase current before filtering and the phase current after filtering; Based on the converted first loop equation and the converted second loop equation, the first conversion relationship and the second conversion relationship are determined respectively.

4. The method according to any one of claims 2 or 3, characterized in that: The converted first loop equation includes a first differential result of the phase current before filtering, the converted second loop equation includes a second differential result of the phase line voltage after filtering, and the first conversion relationship and the second conversion relationship are determined based on the converted first loop equation and the converted second loop equation, respectively, including: Converting the first differential result in the converted first loop equation into a differential operator to obtain a first operator conversion result; Converting the second differential result in the converted second loop equation into a differential operator to obtain a second operator conversion result; The first conversion relationship and the second conversion relationship are determined based on the first operator conversion result and the second operator conversion result.

5. The method according to claim 4, characterized in that The first conversion relationship includes a first coefficient corresponding to the phase current after filtering, the first conversion relationship includes a second coefficient corresponding to the phase line voltage before filtering, the voltage module includes a first voltage module and a second voltage module, and the determining, based on the first conversion relationship, a connection relationship between a plurality of first logic operation units included in the voltage module and the first logic operation unit includes: Based on a preset time constant and the differential operator, a dynamic characteristic coefficient is determined, and the differential operator is discretized to obtain a discrete differential operator; multiplying the dynamic characteristic coefficient by the first coefficient to obtain an updated first coefficient; Determining a first logic operation result corresponding to the filtered phase current in the first conversion relationship based on the updated first coefficient and the discrete differential operator; Based on the first logic operation result, determining a connection relationship between a plurality of first logic operation units included in the first voltage module and the first logic operation unit; Based on the second coefficient and the first logic operation result, a connection relationship between a plurality of first logic operation units included in the second voltage module and the first logic operation unit is determined.

6. The method according to claim 5, characterized in that The determining, based on the second coefficient and the first logic operation result, a connection relationship between a plurality of first logic operation units included in the second voltage module and the first logic operation unit comprises: Determine a first transfer function between the phase line voltage after filtering and the phase line voltage before filtering based on the second coefficient and the first logic operation result; Using the damping coefficient to update the first transfer function, to obtain a second-order damped second transfer function; Determining a third conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering based on the second transfer function and the discrete differential operator; Based on the third conversion relationship, a connection relationship between a plurality of first logic operation units included in the second voltage module and the first logic operation unit is determined.

7. The method according to claim 4, characterized in that The second conversion relationship includes a third coefficient corresponding to the phase line voltage before filtering, the second conversion relationship includes a fourth coefficient corresponding to the phase current after filtering, the current module includes a first current module and a second current module, and the determination of the connection relationship between the plurality of second logic operation units included in the current module and the second logic operation unit based on the second conversion relationship includes: Based on a preset time constant and the differential operator, a dynamic characteristic coefficient is determined, and the differential operator is discretized to obtain a discrete differential operator; multiplying the dynamic characteristic coefficient by the third coefficient to obtain an updated third coefficient; Determining a second logic operation result corresponding to the phase line voltage before filtering in the second conversion relationship based on the updated third coefficient and the discrete differential operator; Based on the second logic operation result, determining a connection relationship between a plurality of second logic operation units included in the first current module and the second logic operation unit; Based on the fourth coefficient and the second logic operation result, a connection relationship between a plurality of second logic operation units included in the second current module and the second logic operation unit is determined.

8. The method according to claim 7, characterized in that The determining, based on the fourth coefficient and the second logic operation result, a connection relationship between a plurality of second logic operation units included in the second current module and the second logic operation unit comprises: determining a third transfer function between the phase current before filtering and the phase current after filtering based on the fourth coefficient and the second logic operation result; Updating the third transfer function by using the damping coefficient to obtain a second-order fourth transfer function with damping; Determining a fourth conversion relationship between the phase current before filtering and the phase current after filtering based on the fourth transfer function and the discrete differential operator; Based on the fourth conversion relationship, a connection relationship between a plurality of second logic operation units included in the second current module and the second logic operation unit is determined.

9. The method according to claim 1, characterized in that: The voltage module includes three-phase voltage modules, the current module includes three-phase current modules, and the simulation model of the filter circuit is constructed based on the connection relationship between the first logic operation units and the connection relationship between the second logic operation units, including: Based on the connection relationship between the first logic operation units, construct the voltage modules of the three phases; Based on the connection relationship between the second logic operation units, construct the current modules of the three phases; A simulation model of the filter circuit is constructed based on the voltage modules of the three phases and the current modules of the three phases.

10. The method according to claim 1, characterized in that After constructing the simulation model of the filter circuit based on the connection relationship between the first logic operation units and the connection relationship between the second logic operation units, the method further includes: Acquire a simulated filtering waveform of the simulation model, and compare the simulated filtering waveform with an actual filtering waveform to obtain a verification result of the simulation model; When the verification result indicates that the simulated filtering waveform is different from the actual filtering waveform, the loop equation of the filtering circuit is re-acquired, and a simulation model of the filtering circuit is constructed based on the re-acquired loop equation.

11. A modeling device for a filter circuit, characterized in that: The device comprises: A first determination module is used to determine a first conversion relationship between the phase line voltage after filtering and the phase line voltage before filtering and the phase current after filtering based on a loop equation of the filtering circuit, and to determine a second conversion relationship between the phase current before filtering and the phase line voltage before filtering and the phase current after filtering; a second determining module, configured to determine a connection relationship between a plurality of first logic operation units included in a voltage module and the first logic operation unit based on the first conversion relationship; a third determining module, configured to determine a connection relationship between a plurality of second logic operation units included in the current module and the second logic operation unit based on the second conversion relationship; A model building module is used to build a simulation model of the filter circuit based on the connection relationship between the first logic operation units and the connection relationship between the second logic operation units.

12. An electronic device, characterized in that: The electronic device comprises: A memory for storing computer executable instructions or computer programs; A processor, configured to implement the filter circuit modeling method according to any one of claims 1 to 10 when executing the computer executable instructions or computer program stored in the memory.

13. A computer-readable storage medium storing computer-executable instructions or a computer program, characterized in that: When the computer executable instructions or computer program are executed by a processor, the modeling method of the filter circuit according to any one of claims 1 to 10 is implemented.

14. A computer program product comprising computer executable instructions or a computer program, characterized in that: When the computer executable instructions or computer program are executed by a processor, the modeling method of the filter circuit according to any one of claims 1 to 10 is implemented.

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