Electromagnetic transient analysis method and device of coaxial cable, computer equipment, readable storage medium and program product

Abstract

The invention relates to an electromagnetic transient analysis method and device of a coaxial cable, computer equipment, a readable storage medium and a program product. The method comprises the following steps: determining the size of a simulation area of the coaxial cable based on the real size of the coaxial cable, and dividing the simulation area of the coaxial cable into a plurality of grids based on the size of the simulation area and a preset rule; on the basis of the magnetic conductivity, the dielectric constant and the conductivity of the outer conductor and the magnetic conductivity, the dielectric constant and the conductivity of the inner conductor, constructing loss impedance of the coaxial cable per unit length to obtain target loss impedance of the coaxial cable per unit length; based on the corrected dielectric constants and the corrected magnetic conductivities corresponding to the grids and the target loss impedance, an electromagnetic analysis model corresponding to the simulation area is constructed; and obtaining an electromagnetic transient analysis result of the coaxial cable based on the electromagnetic analysis model. By adopting the method, electromagnetic transient analysis of the coaxial cable can be realized.

Description

Technical Field

[0001] The present application relates to the technical field of coaxial cables, and in particular to a method, device, computer equipment, readable storage medium and program product for electromagnetic transient analysis of coaxial cables. Background Art

[0002] Coaxial cable is a kind of cable widely used in communication and signal transmission. It consists of a multi-layer concentric structure, usually composed of an inner conductor, an insulating layer, an outer conductor and an outer sheath. Electromagnetic transient analysis of coaxial cables has important practical significance, especially in the wide context of modern high-frequency signal transmission and complex electromagnetic environments. Electromagnetic transient analysis can effectively evaluate the performance of cables under these conditions and ensure the integrity of transmitted signals.

[0003] Therefore, how to conduct electromagnetic transient analysis of coaxial cables has become a problem that needs to be solved urgently. Summary of the invention

[0004] Based on this, it is necessary to provide an electromagnetic transient analysis method, device, computer equipment, readable storage medium and program product for coaxial cables that can realize electromagnetic transient analysis of coaxial cables in response to the above technical problems.

[0005] In a first aspect, the present application provides an electromagnetic transient analysis method for a coaxial cable, wherein the coaxial cable includes an outer conductor and an inner conductor; the method includes: determining the size of a simulation area of ​​the coaxial cable based on the actual size of the coaxial cable, and dividing the simulation area of ​​the coaxial cable into multiple grids based on the size of the simulation area and preset rules; for each grid, obtaining a correction coefficient corresponding to the grid based on the outer radius of the outer conductor and the size of the grid; and correcting the dielectric constant and magnetic permeability corresponding to the grid based on the correction coefficient corresponding to the grid to obtain a corrected dielectric constant and corrected magnetic permeability corresponding to the grid; constructing the loss impedance of the coaxial cable per unit length based on the magnetic permeability, dielectric constant and conductivity of the outer conductor, and the magnetic permeability, dielectric constant and conductivity of the inner conductor to obtain a target loss impedance of the coaxial cable per unit length; constructing an electromagnetic analysis model corresponding to the simulation area based on the corrected dielectric constant and corrected magnetic permeability corresponding to each grid, and the target loss impedance; and obtaining an electromagnetic transient analysis result of the coaxial cable based on the electromagnetic analysis model.

[0006] In one embodiment, based on the magnetic permeability, dielectric constant and conductivity of the outer conductor, and the magnetic permeability, dielectric constant and conductivity of the inner conductor, the loss impedance of the coaxial cable per unit length is constructed to obtain the target loss impedance of the coaxial cable per unit length, including: based on the magnetic permeability, dielectric constant and conductivity of the outer conductor, and the magnetic permeability, dielectric constant and conductivity of the inner conductor, the loss impedance of the coaxial cable per unit length is constructed to obtain the loss impedance of the coaxial cable per unit length; the loss impedance includes a first loss impedance contributed by the current on the inner conductor on the outer surface of the inner conductor, a second loss impedance contributed by the current on the inner conductor on the inner surface of the outer conductor, a third loss impedance contributed by the current on the inner conductor on the outer surface of the outer conductor, a fourth loss impedance contributed by the current on the outer conductor on the inner surface of the outer conductor, and a fifth loss impedance contributed by the current on the outer conductor on the outer surface of the outer conductor; by using a vector matching method, the frequency characteristic curve of the loss impedance is fitted in the complex frequency domain to obtain the loss impedance in the frequency domain; the loss impedance in the frequency domain is converted to obtain the loss impedance in the time domain, and the loss impedance in the time domain is used as the target loss impedance.

[0007] In one of the embodiments, the electromagnetic analysis model includes an electric field analysis model and a magnetic field analysis model; based on the corrected dielectric constant and the corrected magnetic permeability corresponding to each grid, and the target loss impedance, an electromagnetic analysis model corresponding to the simulation area is constructed, including: based on the corrected dielectric constant corresponding to each grid, the conductivity corresponding to each grid, and the target loss impedance, an electric field analysis model corresponding to the simulation area is constructed; based on the corrected magnetic permeability corresponding to each grid and the magnetic permeability corresponding to each grid, a magnetic field analysis model corresponding to the simulation area is constructed.

[0008] In one embodiment, the simulation area includes a first area overlapping with the coaxial cable and a second area excluding the first area; the electric field analysis model includes a first electric field analysis model and a second electric field analysis model; based on the corrected dielectric constant corresponding to each grid, the conductivity corresponding to each grid, and the target loss impedance, an electric field analysis model corresponding to the simulation area is constructed, including: based on the current on the inner conductor and the current on the outer conductor corresponding to each grid in the first area, and the target loss impedance, a first electric field analysis model is constructed; based on the corrected dielectric constant corresponding to each grid in the second area and the conductivity corresponding to each grid, a second electric field analysis model is constructed.

[0009] In one of the embodiments, the simulation area includes a third area overlapping with the port of the coaxial cable and a fourth area excluding the third area; the magnetic field analysis model includes a first magnetic field analysis model and a second magnetic field analysis model; based on the corrected magnetic permeability corresponding to each grid and the magnetic permeability coefficient corresponding to each grid, a magnetic field analysis model corresponding to the simulation area is constructed, including: based on the voltage on the dielectric in the coaxial cable and the magnetic permeability corresponding to each grid in the third area, a first magnetic field analysis model is constructed; based on the corrected magnetic permeability corresponding to each grid in the fourth area and the magnetic permeability coefficient corresponding to each grid, a second magnetic field analysis model is constructed.

[0010] In one embodiment, the current on the inner conductor corresponding to each grid is determined according to the target loss impedance; the current on the outer conductor corresponding to each grid is determined according to the current on the inner conductor corresponding to each grid.

[0011] In a second aspect, the present application also provides an electromagnetic transient analysis device for a coaxial cable, the coaxial cable comprising an outer conductor and an inner conductor; the device comprises: a division module, for determining the size of a simulation area of ​​the coaxial cable based on the actual size of the coaxial cable, and dividing the simulation area of ​​the coaxial cable into a plurality of grids based on the size of the simulation area and a preset rule; a first determination module, for obtaining a correction coefficient corresponding to each grid based on the outer radius of the outer conductor and the size of the grid; and correcting the dielectric constant and magnetic permeability corresponding to the grid based on the correction coefficient corresponding to the grid to obtain a corrected dielectric constant and corrected magnetic permeability corresponding to the grid; a second determination module, for constructing a loss impedance of the coaxial cable per unit length based on the magnetic permeability, dielectric constant and conductivity of the outer conductor, and the magnetic permeability, dielectric constant and conductivity of the inner conductor, so as to obtain a target loss impedance of the coaxial cable per unit length; a third determination module, for constructing an electromagnetic analysis model corresponding to the simulation area based on the corrected dielectric constant and corrected magnetic permeability corresponding to each grid, and the target loss impedance; and obtaining an electromagnetic transient analysis result of the coaxial cable based on the electromagnetic analysis model.

[0012] In one of the embodiments, the second determination module is specifically used to construct the loss impedance of the coaxial cable based on the magnetic permeability, dielectric constant and conductivity of the outer conductor, and the magnetic permeability, dielectric constant and conductivity of the inner conductor, so as to obtain the loss impedance of the coaxial cable per unit length; the loss impedance includes a first loss impedance contributed by the current on the inner conductor on the outer surface of the inner conductor, a second loss impedance contributed by the current on the inner conductor on the inner surface of the outer conductor, a third loss impedance contributed by the current on the inner conductor on the outer surface of the outer conductor, a fourth loss impedance contributed by the current on the outer conductor on the inner surface of the outer conductor, and a fifth loss impedance contributed by the current on the outer conductor on the outer surface of the outer conductor; the frequency characteristic curve of the loss impedance is fitted in the complex frequency domain by the vector matching method to obtain the loss impedance in the frequency domain; the loss impedance in the frequency domain is converted to obtain the loss impedance in the time domain, and the loss impedance in the time domain is used as the target loss impedance.

[0013] In one of the embodiments, the electromagnetic analysis model includes an electric field analysis model and a magnetic field analysis model; the third determination module is specifically used to construct an electric field analysis model corresponding to the simulation area based on the corrected dielectric constant corresponding to each grid, the conductivity corresponding to each grid, and the target loss impedance; and to construct a magnetic field analysis model corresponding to the simulation area based on the corrected magnetic permeability corresponding to each grid and the magnetic permeability coefficient corresponding to each grid.

[0014] In one embodiment, the simulation area includes a first area overlapping with the coaxial cable and a second area excluding the first area; the electric field analysis model includes a first electric field analysis model and a second electric field analysis model; the third determination module includes a first construction module and a second construction module; the first construction module is used to construct a first electric field analysis model based on the current on the inner conductor and the current on the outer conductor corresponding to each grid in the first area, and the target loss impedance; the second construction module is used to construct a second electric field analysis model based on the corrected dielectric constant corresponding to each grid in the second area and the conductivity corresponding to each grid.

[0015] In one embodiment, the simulation area includes a third area overlapping with the port of the coaxial cable and a fourth area excluding the third area; the magnetic field analysis model includes a first magnetic field analysis model and a second magnetic field analysis model; the third determination module includes a third construction module and a fourth construction module; the third construction module is used to construct a first magnetic field analysis model based on the voltage on the dielectric in the coaxial cable and the magnetic permeability corresponding to each grid in the third area; the fourth construction module is used to construct a second magnetic field analysis model based on the corrected magnetic permeability corresponding to each grid in the fourth area and the magnetic permeability corresponding to each grid.

[0016] In one embodiment, the current on the inner conductor corresponding to each grid is determined according to the target loss impedance; the current on the outer conductor corresponding to each grid is determined according to the current on the inner conductor corresponding to each grid.

[0017] In a third aspect, the present application further provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of any one of the methods described in the first aspect when executing the computer program.

[0018] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of any one of the methods described in the first aspect are implemented.

[0019] In a fifth aspect, the present application further provides a computer program product, comprising a computer program, which, when executed by a processor, implements the steps of any one of the methods described in the first aspect.

[0020] In the electromagnetic transient analysis method, device, computer equipment, readable storage medium and program product of the above coaxial cable, the coaxial cable includes an outer conductor and an inner conductor. The simulation area size of the coaxial cable is determined based on the actual size of the coaxial cable, and the simulation area of ​​the coaxial cable is divided into multiple grids based on the simulation area size and preset rules. Then, for each grid, based on the outer radius of the outer conductor and the size of the grid, the correction coefficient corresponding to the grid is obtained, and the dielectric constant and magnetic permeability corresponding to the grid are corrected based on the correction coefficient corresponding to the grid to obtain the corrected dielectric constant and corrected magnetic permeability corresponding to the grid. Then, based on the magnetic permeability, dielectric constant and conductivity of the outer conductor, and the magnetic permeability, dielectric constant and conductivity of the inner conductor, the loss impedance of the coaxial cable per unit length is constructed to obtain the target loss impedance of the coaxial cable per unit length. Then, based on the corrected dielectric constant and corrected magnetic permeability corresponding to each grid, and the target loss impedance, an electromagnetic analysis model corresponding to the simulation area is constructed, and the electromagnetic transient analysis result of the coaxial cable is obtained based on the electromagnetic analysis model, that is, the electromagnetic transient analysis of the coaxial cable is realized. In addition, since the loss impedance is taken into account and the dielectric constant and permeability in the grid are corrected when constructing the electromagnetic analysis model, the constructed electromagnetic analysis model is closer to the actual situation, so the electromagnetic transient analysis results of the coaxial cable are more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0022] FIG1 is a schematic diagram of electromagnetic field vectors in a grid in the related art;

[0023] FIG2 is a schematic diagram of a segmented coaxial cable model in a grid in one embodiment;

[0024] FIG3 is a cross-sectional schematic diagram of a coaxial cable model in one embodiment;

[0025] FIG4 is a schematic flow chart of an electromagnetic transient analysis method for a coaxial cable in one embodiment;

[0026] FIG5 is a schematic diagram of setting a lossy coaxial cable model in a grid in one embodiment;

[0027] FIG6 is a schematic diagram showing the principle of constructing a coaxial cable model in one embodiment;

[0028] FIG7 is a schematic diagram of a flow chart of a method for constructing an electric field analysis model in one embodiment;

[0029] FIG8 is a schematic flow chart of a method for constructing a magnetic field analysis model in one embodiment;

[0030] FIG9 is a schematic diagram of a correction of a magnetic field value at a coaxial cable port in one embodiment;

[0031] FIG10 is a block diagram of an electromagnetic transient analysis device for a coaxial cable in one embodiment;

[0032] FIG. 11 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0034] Coaxial cable is a type of cable widely used in communication and signal transmission. It consists of a multi-layer concentric structure, usually composed of an inner conductor, an insulating layer, an outer conductor, and an outer sheath. The inner conductor is located at the core of the coaxial cable, usually made of copper or silver-plated copper wire, and is used to transmit electrical signals; the insulating layer is an insulating material wrapped around the inner conductor, usually polyethylene or polypropylene, to prevent signal leakage and provide electrical insulation; the outer conductor (also called the shielding layer) surrounds the insulating layer, usually braided copper wire or aluminum foil, and its main function is to shield external electromagnetic interference and provide a ground path for the signal; the outer sheath is the outermost protective shell of the coaxial cable, usually made of rubber or plastic, to prevent physical damage and environmental impact.

[0035] The advantages of coaxial cable include strong anti-interference ability, low signal attenuation, strong broadband transmission capability, high physical strength, easy installation and maintenance, and it is widely used in cable television, Internet broadband, monitoring systems, satellite communications and other fields. The design of coaxial cable includes one or more layers of metal shielding, which can effectively resist electromagnetic interference (EMI) and radio frequency interference (RFI), which makes it very suitable for use in places with complex electromagnetic environments, such as data transmission in cities. The structure of coaxial cable can reduce the attenuation of signals during transmission, especially for long-distance transmission of high-frequency signals. Compared with other cables, such as twisted pair, coaxial cable can transmit longer distances without the use of repeaters. Coaxial cable supports higher frequency signal transmission and has a wide frequency band, so it can be used to transmit large amounts of data, such as TV, Internet and telephone signals. In addition, it is also suitable for analog and digital signal transmission. The plastic or rubber sheath on the outside of coaxial cable provides strong physical protection and can resist environmental damage, mechanical stress and wet weather, making it particularly suitable for use outdoors or in harsh environments. Coaxial cables are easy to terminate and install. Common connectors include F-type, BNC (Bayonet Nut Connector) type, and N-type. They are all simple in design for quick connection and maintenance.

[0036] Electromagnetic transient analysis of coaxial cables has important practical significance, especially in the context of modern high-frequency signal transmission and wide application in complex electromagnetic environments. Electromagnetic transient analysis can effectively evaluate the performance of cables under these conditions and ensure the integrity of transmitted signals. Since coaxial cables are susceptible to external electromagnetic interference and signal reflection under high-frequency signals, electromagnetic transient analysis can help optimize terminal design, reduce reflections, and avoid signal distortion. Through analysis, overvoltage and overcurrent shocks caused by transient phenomena such as lightning strikes and electromagnetic pulses can also be prevented, thereby protecting the cable and extending its service life. In addition, coaxial cables will experience skin effect and dispersion effect in high-frequency applications, resulting in signal loss and distortion. Through electromagnetic transient analysis, these effects can be deeply understood, and the coaxial cable structure can be optimized to reduce losses during signal transmission and improve performance. At the same time, the electromagnetic compatibility of coaxial cables is crucial to system stability. Electromagnetic transient analysis can evaluate the anti-interference ability of coaxial cables in complex electromagnetic environments to ensure that they will not interfere with other devices while maintaining their own stable operation. Electromagnetic transient analysis can also perform modeling and simulation at the system level, and use tools to comprehensively evaluate the performance of coaxial cables in complex communication or power systems to optimize the overall design. In addition, electromagnetic transient analysis can help predict the aging of coaxial cables, perform life prediction and fault diagnosis, ensure that coaxial cables maintain efficient and reliable performance in long-term use, and reduce maintenance costs. Through these means, the safety, reliability and overall performance of coaxial cable systems can be significantly improved.

[0037] In traditional technology, electromagnetic transient analysis of coaxial cables is performed by using the Finite-Difference Time-Domain (FDTD) method. The FDTD algorithm is a powerful electromagnetic field numerical simulation method that is widely used in the electromagnetic characteristics analysis of coaxial cables. This method discretizes the Maxwell equations, divides time and space into grids, and solves the propagation and change process of electromagnetic waves in real time. For coaxial cables, the FDTD algorithm can deeply analyze its transmission characteristics, transient response, electromagnetic interference, and shielding effect. In specific applications, it is first necessary to build a geometric model of the cable, including key parts such as the inner conductor, insulation layer, outer conductor, and outer sheath. To ensure the accuracy of the simulation, the FDTD algorithm is crucial to the selection of spatial step size and time step size. The step size should be set according to the wavelength of the electromagnetic wave and the size of the computational domain, and the absorption boundary condition (Perfectly Matched Layer, PML) is used to prevent electromagnetic wave reflection. The excitation source can be set to a pulse signal or a continuous wave to analyze the transient and steady-state response of the coaxial cable. Through the calculation of the FDTD algorithm, the time domain changes of the electromagnetic field inside the coaxial cable can be obtained. These data can be converted into frequency domain information after Fourier transform to evaluate important parameters such as transmission coefficient, reflection coefficient, characteristic impedance, etc. In addition, the FDTD algorithm can also simulate the performance of coaxial cables under extreme conditions, such as transient response of lightning strikes or electromagnetic pulses, to help design and optimize cable structures. Based on the simulation results, engineers can adjust the material, thickness or shielding layer of the cable as needed to improve anti-interference ability and transmission efficiency. The FDTD algorithm can also be combined with other physical field simulations to evaluate the comprehensive performance of coaxial cables under multiple conditions.

[0038] When using the FDTD algorithm to perform electromagnetic transient analysis on coaxial cables, although it has high accuracy and applicability, it also has some limitations, mainly including the following aspects:

[0039] 1) Large demand for computing resources. The FDTD algorithm needs to discretize space and time and establish a fine grid. Especially for models with complex geometric structures such as coaxial cables, the accuracy of mesh division is required to be high. As the analysis frequency increases, the wavelength of the electromagnetic wave becomes shorter, and the grid density must also increase accordingly, resulting in an exponential increase in the number of grids that need to be processed. High-precision analysis may generate massive amounts of data, and the demand for computing resources (CPU, memory, storage) is very high, especially in three-dimensional simulations. This makes it difficult for the FDTD algorithm to complete calculations in a reasonable time when dealing with large and complex structures.

[0040] 2) Time step limitation. The time step of the FDTD algorithm is limited by the Courant-Friedrich-Levy (CFL) stability condition, and the step size must be small enough to ensure the stability of the numerical calculation. For high-frequency signals or small structures, the reduction of the time step will lead to a significant increase in calculation time. In addition, the FDTD algorithm is an explicit method and cannot skip any time period in the time domain, which means that even if you are only interested in a specific period of the transient response, the entire process still needs to be calculated step by step, further increasing the amount of calculation.

[0041] 3) Limited applicability in cases with complex dielectric parameters. The FDTD algorithm is usually used to deal with cases with uniform or simple electromagnetic media. However, when analyzing complex media (such as highly inhomogeneous dielectric materials, multilayer composite materials, etc.), the computational complexity and error of the FDTD algorithm may increase. In particular, the change of dielectric constant with frequency or the nonlinear behavior of the medium will cause the FDTD algorithm to require more complex modeling and calculations when dealing with these complex electromagnetic phenomena.

[0042] 4) The dissipative effect of materials is difficult to simulate accurately. The FDTD algorithm also has certain limitations in dealing with the dissipative effect of materials in coaxial cables (such as conductor loss). The FDTD algorithm is more suitable for simulating ideal conductors and ideal media. Although the dissipative characteristics of conductors or media can be described by adding loss parameters, its simulation accuracy is not as high as that of the frequency domain method. This limitation is more obvious in long-distance signal transmission or complex material systems.

[0043] Based on the above problems, the inventors proposed an electromagnetic transient analysis method for coaxial cables based on the FDTD algorithm taking into account broadband losses. Before introducing this application, the FDTD algorithm is first introduced in detail as follows to facilitate understanding by non-technical personnel.

[0044] The FDTD algorithm is a global discrete time-domain simulation algorithm. Its calculation area includes not only all simulated objects, but also the areas between simulated objects and their vicinity. At the beginning of the calculation, the calculation area needs to be discretized into a set of parallelepiped grids through the FDTD orthogonal grid. The electromagnetic field in each grid is assumed to be uniformly distributed. The grid size should be encrypted in areas where the electromagnetic field changes dramatically, such as the air-soil interface and the air-conductor interface. Large-size grids can be used in areas where the electromagnetic field changes slowly, such as the air or inside the soil. Take the lower left vertex of each parallelepiped grid as the origin, and define the electric field vectors pointing in the three orthogonal directions of XYZ on the three edges connected to the origin. , , , perpendicular to the three planes connected to the origin, define the magnetic field vectors pointing to the three orthogonal directions of XYZ , , , as shown in Figure 1. The electric field vector and magnetic field vector in each direction need to set the corresponding material parameters according to the relative spatial position, including conductivity , dielectric constant and magnetic permeability .

[0045] When a group of grids are arranged together to form a calculation area, the electromagnetic field vectors are staggered in space by half a space step (i.e., the grid size), and the electromagnetic vectors surround and surround each other, that is, the electric field vector in a certain direction is surrounded by four magnetic field vectors, and vice versa. The electromagnetic field vectors are also staggered in time by half a time step, that is, the overall electric field vector and the overall magnetic field vector are always 0.5 The above time-space characteristics meet the characteristics of solving Maxwell's discrete equations, because the electric field vector and magnetic field vector can be solved in an alternating step-by-step manner. Usually, a complete electromagnetic transient analysis requires tens of thousands of step-by-step iterations until the preset convergence conditions are met or the preset number of iterations is reached.

[0046] The setting of the coaxial cable model in the grid is shown in Figure 2. The coaxial cable model needs to be constructed on the edge of the grid. Its radial size is much smaller than the grid size, that is, there is no need to use the grid to discretize and solve its radial structure. The axial size of the coaxial cable model is discretized into several segments through the grid in the corresponding direction. Each segment of the coaxial cable model coincides with the electric field vector at the corresponding position in space. Among them, the cross-sectional view of the coaxial cable model is shown in Figure 3. The coaxial cable model includes an inner conductor A, an outer conductor B and a dielectric AB. The radius of the inner conductor A is , the inner radius of the outer conductor B is , the outer radius of the outer conductor B is .

[0047] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0048] In one embodiment, as shown in FIG. 4 , a method for electromagnetic transient analysis of a coaxial cable is provided, which is described by applying the method to a computer device, and includes the following steps:

[0049] Step 401, based on the real size of the coaxial cable, determine the size of the simulation area of ​​the coaxial cable, and based on the simulation area size and preset rules, divide the simulation area of ​​the coaxial cable into a plurality of grids.

[0050] The simulation area generally extends about 50% of the space outward on the basis of including all simulated objects to eliminate the influence of boundary effects, stray signal refraction and reflection, etc. The simulated objects include coaxial cables, air, soil, etc. Therefore, the size of the simulation area of ​​the coaxial cable can be determined by expanding the real size of the coaxial cable.

[0051] The preset rules include appropriately encrypting the grid size in the simulated object area with fine structures, such as the air-soil interface, the air-conductor interface, etc., and increasing the grid size in the area where the electromagnetic field changes slowly, such as inside the air or soil, so as to take into account both simulation accuracy and efficiency, that is, while ensuring simulation accuracy, reducing the demand for computing resources. In this way, based on the simulation area size and the predetermined grid sizes of different areas in the simulation area, the simulation area can be divided into multiple grids, and the coordinates of the lower left corner vertex of each grid are recorded, and each grid is coded to distinguish each grid.

[0052] Step 402, for each grid, based on the outer radius of the outer conductor and the size of the grid, obtain a correction coefficient corresponding to the grid; and based on the correction coefficient corresponding to the grid, correct the dielectric constant and permeability corresponding to the grid to obtain a corrected dielectric constant and a corrected permeability corresponding to the grid.

[0053] The coaxial cable model (also called lossy coaxial cable model) is arranged on an edge in an orthogonal direction in the grid and coincides with the electric field vector in that direction, as shown in FIG5 . The coaxial cable model includes an inner conductor A, an outer conductor B, and a dielectric AB. The radius of the inner conductor A is , the inner radius of the outer conductor B is , the outer radius of the outer conductor B is .

[0054] The principle of constructing a coaxial cable model based on cross-scale modeling technology is shown in Figure 6. When the axial electric field vector of the grid is assigned a value of 0, a radius of The lossless coaxial cable model is shown in Figure 6 (c) and (d). Among them, It is called the intrinsic radius of the grid. Through multiple solutions and analyses of the electric field distribution near the coaxial cable model, it can be known that the intrinsic radius ( ) and radial grid size ( ) is .

[0055] The purpose of modeling is to construct a simulation area with an outer radius of The lossy coaxial cable model is shown in Figure 6 (a) and (b). To this end, the conductor surface in Figure 6 (c) and (d) can be compared with the following The dielectric constant and magnetic permeability between the virtual circular surfaces with a radius of Correction is made so that the mutual capacitance and mutual inductance between the conductor surface and the virtual circular surface after correction are equal to the mutual capacitance and mutual inductance in Figure 6 (a) and (b), that is, a coaxial cable model that meets the requirements is constructed without mesh discretization. Correction coefficient It can be obtained by formula (1).

[0056] (1)

[0057] From formula (1), we can see that the correction coefficient The radial mesh size around the coaxial cable model can be and the outer radius of the coaxial cable Directly calculate. It should be noted that the outer radius of the coaxial cable The selection has a limited range, too large or too small outer radius Based on a large number of simulation cases, the outer radius The recommended selection range is .

[0058] Based on the correction factor obtained , the material parameters attached to the electric field vector and magnetic field vector around the coaxial cable model can be modified to construct an equivalent coaxial cable model. The material parameter correction method is as follows:

[0059] 1) Electric field material parameter correction

[0060] The dielectric constants corresponding to the four orthogonal electric field vectors perpendicular to the axis of the coaxial cable model are With correction factor Multiply to obtain the corrected dielectric constant , as shown in Figure 6 (c), and replace the original dielectric constant at the corresponding position.

[0061] (2)

[0062] 2) Magnetic field material parameter correction

[0063] The magnetic permeability corresponding to the four orthogonal magnetic field vectors surrounding the axial direction of the coaxial cable model is With correction factor Divide to obtain the corrected magnetic permeability , as shown in Figure 6 (d), and replace the original magnetic permeability at the corresponding position.

[0064] (3)

[0065] Step 403 , based on the magnetic permeability, dielectric constant and conductivity of the outer conductor, and the magnetic permeability, dielectric constant and conductivity of the inner conductor, the loss impedance of the coaxial cable per unit length is constructed to obtain the target loss impedance of the coaxial cable per unit length.

[0066] Under broadband impact, the current frequency range usually covers DC to several megahertz, and due to the skin effect, the current distribution in the conductor is different at different frequencies. When the frequency is low, the current distribution tends to be uniform. When the frequency is high, the current distribution is concentrated at the inner and outer boundaries of the cross-section of the inner and outer conductors. For a coaxial cable of unit length, the current contribution on the inner conductor A is on the outer surface of the inner conductor A. The first loss impedance , the current on the inner conductor A contributes to the inner surface of the outer conductor B The second loss impedance , the current on the inner conductor A contributes to the outer surface of the outer conductor B The third loss impedance , the current on the outer conductor B contributes to the inner surface of the outer conductor B The fourth loss impedance , the current on the outer conductor B contributes to the outer surface of the outer conductor B The fifth loss impedance , can be obtained by the following function:

[0067] (4)

[0068] (5)

[0069] (6)

[0070] (7)

[0071] (8)

[0072] in, is a plural identifier; is the angular frequency; , are the modified Bessel functions of the first kind of order 0 and 1; , are the modified Bessel functions of the second kind of order 0 and 1; , , ; , , and They are respectively the magnetic permeability, dielectric constant and conductivity of the inner conductor A of the coaxial cable. , , and are the magnetic permeability, dielectric constant and conductivity of the outer conductor B of the coaxial cable respectively.

[0073] In an optional embodiment, the first loss impedance, the second loss impedance, the third loss impedance, the fourth loss impedance and the fifth loss impedance may be directly used as the target loss impedance, or the first loss impedance, the second loss impedance, the third loss impedance, the fourth loss impedance and the fifth loss impedance may be further processed and the processed first loss impedance, the processed second loss impedance, the processed third loss impedance, the processed fourth loss impedance and the processed fifth loss impedance may be used as the target loss impedance.

[0074] Step 404, constructing an electromagnetic analysis model corresponding to the simulation area based on the corrected dielectric constant and the corrected magnetic permeability corresponding to each grid, and the target loss impedance; and obtaining an electromagnetic transient analysis result of the coaxial cable based on the electromagnetic analysis model.

[0075] Optionally, the electromagnetic analysis model includes an electric field analysis model and a magnetic field analysis model; based on the corrected dielectric constant and the corrected magnetic permeability corresponding to each grid, and the target loss impedance, an electromagnetic analysis model corresponding to the simulation area is constructed, including: based on the corrected dielectric constant corresponding to each grid, the conductivity corresponding to each grid, and the target loss impedance, an electric field analysis model corresponding to the simulation area is constructed; based on the corrected magnetic permeability corresponding to each grid and the magnetic permeability corresponding to each grid, a magnetic field analysis model corresponding to the simulation area is constructed.

[0076] The electromagnetic transient analysis result of the coaxial cable is obtained based on the electromagnetic analysis model, including: performing iterative calculation on the electromagnetic analysis model, and obtaining the electromagnetic transient analysis result of the coaxial cable when the iteration meets the termination condition.

[0077] The electromagnetic transient analysis of the above coaxial cable determines the size of the simulation area of ​​the coaxial cable based on the actual size of the coaxial cable, and divides the simulation area of ​​the coaxial cable into multiple grids based on the size of the simulation area and preset rules. Then, for each grid, based on the outer radius of the outer conductor and the size of the grid, the correction coefficient corresponding to the grid is obtained, and the dielectric constant and magnetic permeability corresponding to the grid are corrected based on the correction coefficient corresponding to the grid to obtain the corrected dielectric constant and corrected magnetic permeability corresponding to the grid. Then, based on the magnetic permeability, dielectric constant and conductivity of the outer conductor, and the magnetic permeability, dielectric constant and conductivity of the inner conductor, the loss impedance of the coaxial cable per unit length is constructed to obtain the target loss impedance of the coaxial cable per unit length. Then, based on the corrected dielectric constant and corrected magnetic permeability corresponding to each grid, and the target loss impedance, an electromagnetic analysis model corresponding to the simulation area is constructed, and the electromagnetic transient analysis result of the coaxial cable is obtained based on the electromagnetic analysis model, that is, the electromagnetic transient analysis of the coaxial cable is realized. In addition, since the loss impedance is taken into account and the dielectric constant and permeability in the grid are corrected when constructing the electromagnetic analysis model, the constructed electromagnetic analysis model is closer to the actual situation, so the electromagnetic transient analysis results of the coaxial cable are more accurate.

[0078] In one embodiment, the above step 403 constructs the loss impedance of the coaxial cable per unit length based on the magnetic permeability, dielectric constant and conductivity of the outer conductor, and the magnetic permeability, dielectric constant and conductivity of the inner conductor to obtain the target loss impedance of the coaxial cable per unit length, including:

[0079] Step 4031, construct the loss impedance of the coaxial cable based on the magnetic permeability, dielectric constant and conductivity of the outer conductor, and the magnetic permeability, dielectric constant and conductivity of the inner conductor, and obtain the loss impedance of the coaxial cable per unit length.

[0080] Among them, the loss impedance includes a first loss impedance contributed by the current on the inner conductor on the outer surface of the inner conductor, a second loss impedance contributed by the current on the inner conductor on the inner surface of the outer conductor, a third loss impedance contributed by the current on the inner conductor on the outer surface of the outer conductor, a fourth loss impedance contributed by the current on the outer conductor on the inner surface of the outer conductor, and a fifth loss impedance contributed by the current on the outer conductor on the outer surface of the outer conductor.

[0081] The first loss impedance, the second loss impedance, the third loss impedance, the fourth loss impedance and the fifth loss impedance refer to the above formulas (4) to (8).

[0082] Step 4032: Fit the frequency characteristic curve of the loss impedance in the complex frequency domain by a vector matching method to obtain the loss impedance in the frequency domain.

[0083] The loss impedance obtained by formulas (4) to (8) is expressed as an impedance parameter characteristic curve that changes with frequency. It cannot be directly substituted into the time domain equation of the FDTD algorithm for solution. Therefore, it is necessary to use the vector matching method (Vector Fitting Technique, VFT) to fit the complex impedance parameter characteristics and convert them into a set of rational functions, and then substitute them into the time domain simulation calculation in the form of convolution. Among them, the vector matching method has the advantages of high stability, few iterations, and fast convergence. It has been widely used in microwave, antenna design and other fields. The frequency response fitting technology is relatively mature and will not be repeated here.

[0084] By using the vector matching method, the frequency characteristic curve of the loss impedance per unit length of the coaxial cable can be fitted in the complex frequency domain as follows:

[0085] (9)

[0086] (10)

[0087] (11)

[0088] (12)

[0089] (13)

[0090] in, Characterize the complex frequency domain, is the vector matching order. for The DC component of for The emotional weight of for The remainder of for The extreme point. for The DC component of for The emotional weight of for The remainder of for The extreme point. for The DC component of for The emotional weight of for The remainder of for The extreme point. for The DC component of for The emotional weight of for The remainder of for The extreme point. for The DC component of for The emotional weight of for The remainder of for It should be noted that as many frequency points as possible should be evenly selected within each frequency order of magnitude of the original characteristic frequency curve to improve the accuracy of curve fitting.

[0091] Step 4033, convert the loss impedance in the frequency domain to obtain the loss impedance in the time domain, and use the loss impedance in the time domain as the target loss impedance.

[0092] Optionally, perform an inverse Laplace transform on equations (9) to (13) to transform them into a time domain convolution form to obtain the first loss impedance in the time domain: , the second loss impedance , the third loss impedance , the fourth loss impedance , Fifth loss impedance , and use it as the target loss impedance.

[0093] In one of the embodiments, before constructing an electromagnetic analysis model corresponding to the simulation area based on the corrected dielectric constant and the corrected magnetic permeability corresponding to each grid, and the target loss impedance, the method further includes: determining a time step.

[0094] Specifically, the selection range of the time step of the FDTD algorithm is determined by the minimum grid size and needs to meet the CFL criterion to prevent data divergence, oscillation, non-convergence and other problems that may occur in time domain calculations, namely:

[0095] (14)

[0096] in, , , is the minimum grid size in the three orthogonal directions of X, Y, and Z. is the propagation speed of light in the corresponding medium. In general, the time step is selected as the maximum value in formula (14) to reduce the number of simulations and improve simulation efficiency.

[0097] In one embodiment, the simulation area includes a first area overlapping the coaxial cable and a second area other than the first area, that is, the second area is other areas of the simulation area other than the first area. The electric field analysis model includes a first electric field analysis model and a second electric field analysis model.

[0098] As shown in FIG7 , a method for constructing an electric field analysis model is provided. Based on the corrected dielectric constant corresponding to each grid, the conductivity corresponding to each grid, and the target loss impedance, an electric field analysis model corresponding to the simulation area is constructed, including the following steps:

[0099] Step 701: construct a first electric field analysis model based on the current on the inner conductor and the current on the outer conductor corresponding to each grid in the first area, and the target loss impedance.

[0100] The first electric field analysis model is constructed as follows:

[0101] (15)

[0102] in, , , , ; The number of time steps is Time The electric field on a coaxial cable segment; represents the number of time steps; represents the time step; , are the current on the inner conductor A and the current on the outer conductor B respectively; and is the convolution term, and the iterative calculation formula is as follows:

[0103] (16a)

[0104] (16b)

[0105] in, , In order to ensure the stability of the simulation, the time step can be appropriately reduced when combined with the time domain convolution calculation. According to current practical experience, the time step generally needs to be reduced to between 0.8 and 0.9 times.

[0106] Step 702: construct a second electric field analysis model based on the corrected dielectric constant corresponding to each grid in the second region and the conductivity corresponding to each grid.

[0107] It can be understood that the modified dielectric constant and conductivity corresponding to the grid respectively represent the modified dielectric constant and conductivity in the space corresponding to the grid.

[0108] The second electric field analysis model is in the form of an iterative equation, and its iteration process involves the electric field vector value of the previous time step and the four magnetic field vectors surrounding the electric field vector. Therefore, the constructed second electric field analysis model is as follows:

[0109] (17)

[0110] in, , , are the electric field vectors in three orthogonal directions, , , is the electric field vector position number based on the grid number, represents the number of time steps, , They represent the conductivity and the corrected dielectric constant in the corresponding space respectively.

[0111] In one embodiment, the simulation area includes a third area overlapping with the port of the coaxial cable and a fourth area other than the third area; that is, the fourth area is other areas of the simulation area other than the third area. The magnetic field analysis model includes a first magnetic field analysis model and a second magnetic field analysis model.

[0112] As shown in FIG8 , a method for constructing a magnetic field analysis model is provided. Based on the corrected magnetic permeability corresponding to each grid and the magnetic permeability coefficient corresponding to each grid, a magnetic field analysis model corresponding to the simulation area is constructed, including the following steps:

[0113] Step 801: construct a first magnetic field analysis model based on the voltage on the dielectric in the coaxial cable and the magnetic permeability corresponding to each grid in the third region, wherein the voltage on the dielectric in the coaxial cable may be the port voltage of the dielectric.

[0114] It can be understood that the magnetic permeability corresponding to the grid represents the magnetic permeability in the space corresponding to the grid.

[0115] At the port of the coaxial cable, since the port voltage of dielectric AB is exposed, when calculating the four magnetic field vectors around the cable, the influence of the port voltage of dielectric AB on the magnetic field vector must be considered. , , , The magnetic field vector calculation equations need to be superimposed The impact of is shown in Figure 9.

[0116] by For example, the magnetic field vector is The magnetic field at the moment is:

[0117] (18)

[0118] in, represents the magnetic permeability in the corresponding space, Represents the port voltage of dielectric AB.

[0119] Step 802: construct a second magnetic field analysis model based on the corrected magnetic permeability corresponding to each grid in the fourth region and the magnetic permeability coefficient corresponding to each grid.

[0120] The constructed second magnetic field analysis model is as follows:

[0121] (19)

[0122] in, , They represent the corrected magnetic permeability and magnetic permeability respectively, and the magnetic permeability is generally set to 0. Compared with the magnetic field analysis model in the traditional technology, the magnetic permeability corresponding to the four orthogonal magnetic field vectors surrounding the axial direction of the coaxial cable model in this embodiment is replaced by the corrected magnetic permeability. .

[0123] In one embodiment, the voltage distribution on the dielectric AB in the coaxial cable can be solved by the transmission line equation, which is as follows:

[0124] (20)

[0125] in, , is the relative dielectric constant of dielectric AB, is the dielectric constant of vacuum.

[0126] In one embodiment, the current on the inner conductor corresponding to each grid is determined according to the target loss impedance; the current on the outer conductor corresponding to each grid is determined according to the current on the inner conductor corresponding to each grid.

[0127] Specifically, the total current used to calculate the axial electric field of the coaxial cable in the next cycle is , from the simulation area The magnetic field vector loop integral is estimated at time , for the axial direction , No. The total current flowing through the coaxial cable cross section is The calculation equation is as follows:

[0128] (twenty one)

[0129] in, Indicates the position number corresponding to the grid after the coaxial cable is segmented along the axial direction.

[0130] 1) Current on inner conductor A

[0131] The current on the inner conductor A of the coaxial cable is obtained by the historical current on the inner conductor A, the total current and the voltage distribution of the dielectric AB. The calculation formula is as follows:

[0132] (twenty two)

[0133] The equations for solving the coefficients are as follows

[0134]

[0135]

[0136]

[0137]

[0138]

[0139]

[0140]

[0141]

[0142]

[0143]

[0144] and is the convolution term, and the iterative calculation formula is as follows

[0145] (23a)

[0146] (23b)

[0147] (23c)

[0148] (23d)

[0149] in, , , .

[0150] 2) Current on the outer conductor B

[0151] The current on the outer conductor B of the coaxial cable is calculated by subtracting the current on the inner conductor A from the total current at the current moment, that is,

[0152] (twenty four)

[0153] Based on this, formulas (15)-(24) are repeatedly solved iteratively. Each iteration is equivalent to updating the electromagnetic field quantity in the calculation area in time and estimating it to the next time step. , realizing the step-by-step solution of electromagnetic field quantities in time. When the calculation iteration meets the termination condition, the electromagnetic field calculation is terminated and the calculation results are output, that is, the transient analysis results are obtained.

[0154] The termination condition may be the number of iterations, that is, when the number of electromagnetic field updates reaches a preset number of iterations, the electromagnetic field calculation is terminated. The termination condition may also be a convergence condition, that is, when the spatial electromagnetic field is in a steady-state distribution, or forms a periodic change and the waveform deviation of two adjacent periods meets the convergence condition, the electromagnetic field calculation is terminated.

[0155] In addition, at the beginning of the iteration, the excitation is set at the specified location in the form of a spatial electromagnetic field or a lumped circuit parameter element according to actual needs.

[0156] In summary, this application divides the simulation area into two parts, namely the inside of the coaxial cable and the outside of the coaxial cable; the traditional FDTD algorithm is used for the outside of the coaxial cable to solve the distribution characteristics of the electromagnetic field quantity under spatial transient impact through spatial discretization and electromagnetic field quantity iteration; the coaxial cable adopts cross-scale modeling technology, without the need for extremely fine grid discretization, and the coaxial cable model can be equivalently constructed by modifying the material parameters around the coaxial cable; the electromagnetic distribution inside the coaxial cable is solved in time domain form using the multi-conductor segmented transmission line method, which can accurately calculate the current distribution flowing through the inner and outer conductors of the coaxial cable and the voltage distribution in the dielectric under the premise of considering the frequency-varying loss; the frequency-varying impedance per unit length of the coaxial cable is calculated using the Bessel method. The FDTD electromagnetic field vector calculation is embedded in the impedance characteristics considering the broadband effect through the inverse Laplace transform. The internal electromagnetic field of the coaxial cable affects the electromagnetic environment outside the cable through the electromagnetic loss on the outer surface of the outer conductor and the dielectric voltage at the cable port. The electromagnetic field outside the coaxial cable affects the electromagnetic field inside the coaxial cable through the spatial magnetic field loop integral in the vicinity of the cable. The electromagnetic fields inside and outside the coaxial cable are bidirectionally coupled in each calculation cycle to ensure the accuracy of the calculation results.

[0157] In addition, compared with the traditional FDTD algorithm, the cross-scale modeling technology does not require dense network discretization of the internal space of the coaxial cable, and the external electromagnetic field of the coaxial cable can be solved based on a large-size discrete grid, thereby reducing memory usage, increasing the time step, and improving computational efficiency.

[0158] In addition, Bessel functions and transmission line equations are used to solve the frequency-varying impedance of coaxial cables, eliminating the need to generate complex high-order circuit matrices, greatly improving the stability and solution accuracy of electromagnetic transient analysis.

[0159] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0160] Based on the same inventive concept, the embodiment of the present application also provides an electromagnetic transient analysis device for a coaxial cable for implementing the electromagnetic transient analysis method for a coaxial cable involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in the embodiments of the electromagnetic transient analysis device for one or more coaxial cables provided below can refer to the limitations of the electromagnetic transient analysis method for a coaxial cable above, and will not be repeated here.

[0161] In an exemplary embodiment, as shown in FIG10 , a coaxial cable electromagnetic transient analysis device is provided, the coaxial cable comprising an outer conductor and an inner conductor; the coaxial cable electromagnetic transient analysis device 1000 comprises: a division module 1001, a first determination module 1002, a second determination module 1003 and a third determination module 1004, wherein:

[0162] The division module 1001 is used to determine the size of the simulation area of ​​the coaxial cable based on the real size of the coaxial cable, and divide the simulation area of ​​the coaxial cable into multiple grids based on the simulation area size and preset rules.

[0163] The first determination module 1002 is used to obtain a correction coefficient corresponding to each grid based on the outer radius of the outer conductor and the size of the grid; and to correct the dielectric constant and magnetic permeability corresponding to the grid based on the correction coefficient corresponding to the grid to obtain a corrected dielectric constant and corrected magnetic permeability corresponding to the grid.

[0164] The second determination module 1003 is used to construct the loss impedance of the coaxial cable per unit length based on the magnetic permeability, dielectric constant and conductivity of the outer conductor and the magnetic permeability, dielectric constant and conductivity of the inner conductor to obtain the target loss impedance of the coaxial cable per unit length.

[0165] The third determination module 1004 is used to construct an electromagnetic analysis model corresponding to the simulation area based on the corrected dielectric constant and the corrected magnetic permeability corresponding to each grid, and the target loss impedance; and obtain the electromagnetic transient analysis result of the coaxial cable based on the electromagnetic analysis model.

[0166] In one embodiment, the second determination module 1003 is specifically used to construct the loss impedance of the coaxial cable based on the magnetic permeability, dielectric constant and conductivity of the outer conductor, and the magnetic permeability, dielectric constant and conductivity of the inner conductor, so as to obtain the loss impedance of the coaxial cable per unit length; the loss impedance includes a first loss impedance contributed by the current on the inner conductor on the outer surface of the inner conductor, a second loss impedance contributed by the current on the inner conductor on the inner surface of the outer conductor, a third loss impedance contributed by the current on the inner conductor on the outer surface of the outer conductor, a fourth loss impedance contributed by the current on the outer conductor on the inner surface of the outer conductor, and a fifth loss impedance contributed by the current on the outer conductor on the outer surface of the outer conductor; the frequency characteristic curve of the loss impedance is fitted in the complex frequency domain by the vector matching method to obtain the loss impedance in the frequency domain; the loss impedance in the frequency domain is converted to obtain the loss impedance in the time domain, and the loss impedance in the time domain is used as the target loss impedance.

[0167] In one embodiment, the electromagnetic analysis model includes an electric field analysis model and a magnetic field analysis model; the third determination module 1004 is specifically used to construct an electric field analysis model corresponding to the simulation area based on the corrected dielectric constant corresponding to each grid, the conductivity corresponding to each grid, and the target loss impedance; based on the corrected magnetic permeability corresponding to each grid and the magnetic permeability coefficient corresponding to each grid, construct a magnetic field analysis model corresponding to the simulation area.

[0168] In one embodiment, the simulation area includes a first area overlapping with the coaxial cable and a second area excluding the first area; the electric field analysis model includes a first electric field analysis model and a second electric field analysis model; the third determination module 1004 includes a first construction module and a second construction module; the first construction module is used to construct a first electric field analysis model based on the current on the inner conductor and the current on the outer conductor corresponding to each grid in the first area, and the target loss impedance; the second construction module is used to construct a second electric field analysis model based on the corrected dielectric constant corresponding to each grid in the second area and the conductivity corresponding to each grid.

[0169] In one embodiment, the simulation area includes a third area overlapping with the port of the coaxial cable and a fourth area other than the third area; the magnetic field analysis model includes a first magnetic field analysis model and a second magnetic field analysis model; the third determination module 1004 includes a third construction module and a fourth construction module; the third construction module is used to construct a first magnetic field analysis model based on the voltage on the dielectric in the coaxial cable and the magnetic permeability corresponding to each grid in the third area; the fourth construction module is used to construct a second magnetic field analysis model based on the corrected magnetic permeability corresponding to each grid in the fourth area and the magnetic permeability corresponding to each grid.

[0170] In one embodiment, the current on the inner conductor corresponding to each grid is determined according to the target loss impedance; the current on the outer conductor corresponding to each grid is determined according to the current on the inner conductor corresponding to each grid.

[0171] Each module in the above-mentioned electromagnetic transient analysis device for coaxial cable can be implemented in whole or in part by software, hardware and their combination. Each module can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the corresponding operations of each module.

[0172] In an exemplary embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be shown in FIG11. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit, and an input device. The processor, the memory, and the input / output interface are connected via a system bus, and the communication interface, the display unit, and the input device are connected to the system bus via the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner may be implemented through WIFI, a mobile cellular network, near field communication (NFC) or other technologies. When the computer program is executed by the processor, a method for electromagnetic transient analysis of a coaxial cable is implemented. The display unit of the computer device is used to form a visually visible picture, which may be a display screen, a projection device, or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the computer device shell, or an external keyboard, touchpad or mouse.

[0173] Those skilled in the art will understand that the structure shown in FIG. 11 is merely a block diagram of a partial structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

[0174] In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the steps described in the above-mentioned embodiment of the electromagnetic transient analysis method of the coaxial cable are implemented.

[0175] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps described in the above-mentioned embodiment of the electromagnetic transient analysis method for a coaxial cable are implemented.

[0176] In one embodiment, a computer program product is provided, including a computer program, which, when executed by a processor, implements the steps described in the above-mentioned embodiment of the electromagnetic transient analysis method for a coaxial cable.

[0177] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0178] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0179] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for electromagnetic transient analysis of a coaxial cable, characterized in that: The coaxial cable comprises an outer conductor and an inner conductor; the method comprises: Determining a simulation area size of the coaxial cable based on a real size of the coaxial cable, and dividing the simulation area of ​​the coaxial cable into a plurality of grids based on the simulation area size and a preset rule; For each of the grids, a correction coefficient corresponding to the grid is obtained based on the outer radius of the outer conductor and the size of the grid; and the dielectric constant and the magnetic permeability corresponding to the grid are corrected based on the correction coefficient corresponding to the grid to obtain a corrected dielectric constant and a corrected magnetic permeability corresponding to the grid; Based on the magnetic permeability, dielectric constant and conductivity of the outer conductor, and the magnetic permeability, dielectric constant and conductivity of the inner conductor, the loss impedance of the coaxial cable per unit length is constructed to obtain a target loss impedance of the coaxial cable per unit length; Based on the corrected dielectric constant and the corrected magnetic permeability corresponding to each of the grids, and the target loss impedance, an electromagnetic analysis model corresponding to the simulation area is constructed; and based on the electromagnetic analysis model, an electromagnetic transient analysis result of the coaxial cable is obtained.

2. The method according to claim 1, characterized in that The method of constructing the loss impedance of the coaxial cable per unit length based on the magnetic permeability, dielectric constant and conductivity of the outer conductor and the magnetic permeability, dielectric constant and conductivity of the inner conductor to obtain the target loss impedance of the coaxial cable per unit length includes: The loss impedance of the coaxial cable is constructed based on the magnetic permeability, dielectric constant and conductivity of the outer conductor, and the magnetic permeability, dielectric constant and conductivity of the inner conductor, so as to obtain the loss impedance of the coaxial cable per unit length; the loss impedance includes a first loss impedance contributed by the current on the inner conductor on the outer surface of the inner conductor, a second loss impedance contributed by the current on the inner conductor on the inner surface of the outer conductor, a third loss impedance contributed by the current on the inner conductor on the outer surface of the outer conductor, a fourth loss impedance contributed by the current on the outer conductor on the inner surface of the outer conductor, and a fifth loss impedance contributed by the current on the outer conductor on the outer surface of the outer conductor; By means of a vector matching method, the frequency characteristic curve of the loss impedance is fitted in the complex frequency domain to obtain the loss impedance in the frequency domain; The loss impedance in the frequency domain is converted to obtain the loss impedance in the time domain, and the loss impedance in the time domain is used as the target loss impedance.

3. The method according to claim 1, characterized in that The electromagnetic analysis model includes an electric field analysis model and a magnetic field analysis model; the electromagnetic analysis model corresponding to the simulation area is constructed based on the corrected dielectric constant and the corrected magnetic permeability corresponding to each of the grids, and the target loss impedance, including: Based on the corrected dielectric constant corresponding to each of the grids, the conductivity corresponding to each of the grids, and the target loss impedance, an electric field analysis model corresponding to the simulation area is constructed; Based on the corrected magnetic permeability corresponding to each of the grids and the magnetic permeability coefficient corresponding to each of the grids, a magnetic field analysis model corresponding to the simulation area is constructed.

4. The method according to claim 3, characterized in that: The simulation area includes a first area overlapping with the coaxial cable and a second area other than the first area; the electric field analysis model includes a first electric field analysis model and a second electric field analysis model; the electric field analysis model corresponding to the simulation area is constructed based on the corrected dielectric constant corresponding to each of the grids, the conductivity corresponding to each of the grids, and the target loss impedance, including: constructing the first electric field analysis model based on the current on the inner conductor and the current on the outer conductor corresponding to each of the grids in the first region, and the target loss impedance; The second electric field analysis model is constructed based on the corrected dielectric constant corresponding to each of the grids in the second region and the conductivity corresponding to each of the grids.

5. The method according to claim 3, characterized in that: The simulation area includes a third area overlapping with the port of the coaxial cable and a fourth area other than the third area; the magnetic field analysis model includes a first magnetic field analysis model and a second magnetic field analysis model; the magnetic field analysis model corresponding to the simulation area is constructed based on the corrected magnetic permeability corresponding to each of the grids and the magnetic permeability coefficient corresponding to each of the grids, including: constructing the first magnetic field analysis model based on the voltage on the dielectric in the coaxial cable and the magnetic permeability corresponding to each of the grids in the third region; The second magnetic field analysis model is constructed based on the corrected magnetic permeability corresponding to each of the grids in the fourth region and the magnetic permeability coefficient corresponding to each of the grids.

6. The method according to claim 4, characterized in that The current on the inner conductor corresponding to each of the grids is determined based on the target loss impedance; the current on the outer conductor corresponding to each of the grids is determined based on the current on the inner conductor corresponding to each of the grids.

7. An electromagnetic transient analysis device for a coaxial cable, characterized in that: The coaxial cable comprises an outer conductor and an inner conductor; the device comprises: A division module, used to determine the size of the simulation area of ​​the coaxial cable based on the real size of the coaxial cable, and divide the simulation area of ​​the coaxial cable into a plurality of grids based on the simulation area size and a preset rule; A first determination module is used to obtain, for each of the grids, a correction coefficient corresponding to the grid based on the outer radius of the outer conductor and the size of the grid; and to correct the dielectric constant and magnetic permeability corresponding to the grid based on the correction coefficient corresponding to the grid to obtain a corrected dielectric constant and corrected magnetic permeability corresponding to the grid; A second determination module is used to construct the loss impedance of the coaxial cable per unit length based on the magnetic permeability, dielectric constant and conductivity of the outer conductor and the magnetic permeability, dielectric constant and conductivity of the inner conductor to obtain a target loss impedance of the coaxial cable per unit length; The third determination module is used to construct an electromagnetic analysis model corresponding to the simulation area based on the corrected dielectric constant and the corrected magnetic permeability corresponding to each of the grids, and the target loss impedance; and obtain the electromagnetic transient analysis result of the coaxial cable based on the electromagnetic analysis model.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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