Rail transit system electromagnetic simulation method, device and equipment and storage medium

Abstract

The invention discloses the technical field of rail transit simulation, and particularly relates to a rail transit system electromagnetic simulation method, device and equipment and a storage medium. The method comprises the following steps: S1, establishing a geometric entity model of the rail transit system, wherein the geometric entity model comprises a traction power supply system model, a traction transmission system model and a communication system model; s2, measuring parameters of the geometric solid model, and establishing a finite element simulation model according to the parameters; s3, setting port excitation for the finite element simulation model, wherein the port excitation comprises voltage, current and frequency parameters; and S4, through three-dimensional electromagnetic field simulation software, based on the finite element simulation model and the port excitation, obtaining an electromagnetic field distribution condition of the rail transit system, and analyzing a coupling path of an interference source and sensitive equipment. Simulation is carried out based on real measurement data through the geometric solid model, electromagnetic field distribution under various operation conditions can be simulated, and an economical and efficient rail transit simulation scheme is provided.

Description

Technical Field

[0001] The present invention relates to the technical field of rail transit simulation, and in particular to a rail transit system electromagnetic simulation method, device, equipment and storage medium. Background Art

[0002] The development of electrified railways is crucial to the nation's economic vitality, and the construction of rail transit systems is a major project that affects public transportation. However, with the widespread use of electronic devices and high-precision digital equipment, the electromagnetic environment of rail transit systems has gradually deteriorated, becoming a major constraint on their development. Rail transit systems are complex, and nearly every device requires electromagnetic signals to function properly. The combined coupling effects of electromagnetic interference can cause these sensitive devices to malfunction. At the very least, this can increase information transmission delays and call drop rates, while at worst, it can cause operational failures and even threaten personnel safety.

[0003] Due to the varying device layouts within each subsystem and the interconnection methods between systems, electromagnetic interference typically propagates through multiple pathways, primarily radiation coupling caused by electromagnetic wave propagation and conduction coupling through complete circuit connections. In the ever-changing field operating environment, interference between interference sources and sensitive equipment often results from the combined effects of multiple coupling pathways, significantly complicating theoretical analysis and electromagnetic environment assessment.

[0004] While direct and effective, on-site measurements are labor-intensive and costly. Furthermore, laboratory simulations are overly idealized and fail to reflect the complexities of real-world engineering. Therefore, a more innovative analysis method is urgently needed to more accurately reproduce the actual electromagnetic environment. Computer-aided tools, particularly 3D electromagnetic simulation software, can create precise models with a high degree of environmental fidelity, making it easier to observe the distribution of electromagnetic fields, enabling early prediction of electromagnetic interference and more cost-effective assessments.

[0005] At present, although computational simulation tools such as Simulink can analyze the electromagnetic environment to a certain extent, the results are often difficult to display intuitively. The application of existing finite element software in electromagnetic simulation is mostly focused on device-level analysis, and there is no solution that can intuitively present the three-dimensional electromagnetic field distribution around the rail transit system. Therefore, when conducting a comprehensive assessment of the electromagnetic environment of the rail transit system, the existing technology faces the technical problem of being unable to accurately model and analyze the three-dimensional electromagnetic field distribution. These problems are precisely the key issues that the present invention aims to solve. The method of the present invention can effectively overcome the above-mentioned technical problems, thereby achieving a more accurate and efficient simulation and evaluation of the electromagnetic environment of the rail transit system. Summary of the Invention

[0006] The present invention aims to address existing issues such as complex electromagnetic environments, diverse interference coupling pathways, and limitations in simulation methods by providing an electromagnetic simulation method for rail transit systems. This method achieves efficient, economical, and accurate simulation and evaluation of the rail transit system's electromagnetic environment by accurately modeling each subsystem of the system, setting material properties and excitation parameters, performing comprehensive coupling analysis, and utilizing three-dimensional electromagnetic field simulation software to obtain electromagnetic field distribution. This method improves the accuracy of electromagnetic interference prediction and the comprehensiveness of system evaluation.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] In a first aspect, an embodiment of the present application provides a rail transit system electromagnetic simulation method, comprising the following steps:

[0009] S1. Establish a geometric entity model of the rail transit system, the geometric entity model includes a traction power supply system model, a traction drive system model, and a communication system model;

[0010] S2. Determining the parameters of the geometric solid model, and establishing a finite element simulation model based on the parameters;

[0011] S3. Setting port excitation for the finite element simulation model, including voltage, current and frequency parameters;

[0012] S4. Using three-dimensional electromagnetic field simulation software, based on the finite element simulation model and the port excitation, obtain the electromagnetic field distribution of the rail transit system and analyze the coupling path between the interference source and the sensitive equipment.

[0013] In this implementation, a comprehensive geometric solid model of the rail transit system is established to ensure the comprehensiveness and accuracy of the simulation. This allows subsequent simulations to fully reflect the actual electromagnetic behavior of the system, enhancing the reliability and practicality of the simulation.

[0014] In some embodiments, the traction power supply system model includes a pantograph, a contact network, a transmission line, a transformer, a converter, an inverter, and a traction motor; and performing electromagnetic simulation on the traction power supply system model includes the following steps:

[0015] S111. The overhead line obtains high-voltage power through the pantograph, and the transformer converts the high-voltage power into low-voltage AC power;

[0016] S112. The converter converts the low-voltage AC power into DC power, and the inverter converts the DC power into AC power with adjustable frequency and amplitude, which is ultimately supplied to the traction motor;

[0017] S113. Set port excitation for the transmission line in the traction motor to simulate the impact of the transmission line on the electromagnetic field distribution of the rail transit system.

[0018] In the above implementation, the traction power supply system is specifically simulated, which can accurately simulate the power collection, conversion and supply process, thereby more accurately evaluating the performance of the system in actual operation and improving the efficiency of system design and maintenance.

[0019] In some embodiments, the transmission line in step S113 uses a three-core cable to simulate the impact of the multi-layer structure of the three-core cable on the electromagnetic field distribution of the rail transit system.

[0020] In the above implementation, by simulating the impact of the multi-layer structure of the three-core cable on the electromagnetic field, an in-depth understanding of cable design and material selection is provided, which helps to optimize the electromagnetic compatibility and safety of the cable.

[0021] In some embodiments, the traction drive system model includes a transformer, a three-phase asynchronous motor, a converter, and an inverter; performing electromagnetic simulation on the traction drive system model includes the following steps:

[0022] S121 sets the transformer material, coil turns, current and cross-sectional current density; obtain low voltage AC power through the transformer;

[0023] S122. Using a converter to convert the AC power output of the transformer into DC power, and then converting the DC power into AC power with adjustable frequency and amplitude;

[0024] S123. Simulate the physical parameters of the stator winding and the magnetic field distribution of the rotor of the three-phase asynchronous motor, set the port excitation for the three-phase asynchronous motor, and simulate the electromagnetic field distribution of the three-phase asynchronous motor after being subjected to the port excitation.

[0025] In this implementation, detailed simulation of the electromagnetic characteristics of the traction drive system, particularly at the transformer, converter, and motor levels, enables system designers to accurately predict and adjust system performance under various operating conditions.

[0026] In some embodiments, the converter described in S122 is a four-quadrant IGBT converter.

[0027] In the above implementation, the use of a four-quadrant IGBT converter enhances the functionality of the converter, allowing for more flexible and efficient power conversion, adapting to a wider range of operating requirements, and thereby improving the overall performance and energy efficiency of the system.

[0028] In some embodiments, the communication system model is modeled based on a microstrip patch antenna; the microstrip patch antenna uses FR-4 as a dielectric substrate material with a relative dielectric constant of 4.4.

[0029] In the above implementation, by using a specific material FR-4 as the dielectric substrate of the microstrip patch antenna, the antenna design is optimized, its working efficiency and signal quality are improved, and the reliability and stability of the communication system are ensured.

[0030] In a second aspect, an embodiment of the present application provides an electromagnetic simulation device for a rail transit system, the simulation device comprising:

[0031] A model building unit, configured with interfaces and tools for creating and editing geometric entity models of rail transit systems, including traction power supply system models, traction drive system models, and communication system models;

[0032] a parameter determination unit, configured to receive the geometric solid model output from the model building unit, and determine various parameters of the model, thereby establishing a corresponding finite element model;

[0033] Excitation configuration unit, used to set the port excitation of the finite element model, including setting voltage, current and frequency parameters;

[0034] The simulation execution unit is equipped with 3D electromagnetic field simulation software, which is used to perform simulation operations based on the set finite element model and port excitation to obtain the electromagnetic field distribution of the rail transit system and analyze the coupling path between interference sources and sensitive equipment;

[0035] The result analysis unit is used to receive the electromagnetic field data output by the simulation execution unit and perform data analysis and visualization.

[0036] In the above implementation, the system device provides a one-stop solution, from model establishment to parameter determination, excitation configuration, simulation execution and result analysis, providing users with efficient and accurate simulation tools to support complex rail transit electromagnetic simulation needs.

[0037] In a third aspect, an embodiment of the present application provides a computer device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the method for electromagnetic simulation of a rail transit system is implemented.

[0038] In the above implementation, by implementing the simulation method on a computer device, the method can be widely deployed on different hardware, thereby enhancing the accessibility and flexibility of the method.

[0039] In a fourth aspect, an embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, a method for electromagnetic simulation of a rail transit system is implemented.

[0040] In the above implementation, the computer-readable storage medium provides a convenient way to distribute and deploy the simulation program, ensuring that different users can easily implement the simulation method on their devices, thereby promoting the popularization and application of the technology.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] Existing field measurements are not only costly but also difficult to accurately perform in complex environments. Traditional laboratory simulations are often based on simplified assumptions and fail to fully consider the complex environment and special operating conditions of train operation. By constructing a detailed geometric solid model and performing simulations based on real-world measurement data, this method can accurately simulate the electromagnetic field distribution under various operating conditions, thereby improving the practicality and accuracy of the simulation. Furthermore, by setting specific current and voltage excitations, this method can effectively simulate the actual impact of interference sources such as pantograph arcs on the electromagnetic environment, providing an economical and efficient solution for evaluating and optimizing the electromagnetic compatibility of rail transit systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a flow chart of an electromagnetic simulation method for a rail transit system according to embodiment 1 of the present invention;

[0044] Figure 2 This is a block diagram of an electromagnetic simulation system for a rail transit system according to embodiment 2 of the present invention;

[0045] Figure 3 This is a schematic diagram of a three-core cable model according to embodiment 2 of the present invention;

[0046] Figure 4 Schematic diagram of a transformer model according to embodiment 2 of the present invention;

[0047] Figure 5 Schematic diagram of a converter model according to embodiment 2 of the present invention;

[0048] Figure 6 Schematic diagram of a motor model according to embodiment 2 of the present invention;

[0049] Figure 7 Schematic diagram of the power transmission path of the traction drive system of embodiment 2 of the present invention;

[0050] Markings in the figure: 1-catenary, 2-transformer, 3-interior of traction converter, 4-inverter, 5-traction motor;

[0051] Figure 8 This is a structural diagram of a three-core cable according to embodiment 2 of the present invention;

[0052] Markings in the figure: 1-PVC outer sheath, 2-steel tape armor layer, 3-PVC inner lining layer, 4-non-woven fabric cabling wrap, 5-copper tape shield layer, 6-outer shield layer, 7-XLPE insulation shield layer, 8-inner shield layer, 9-conductor;

[0053] Figure 9 This is a circuit structure schematic diagram of a four-quadrant converter according to embodiment 2 of the present invention;

[0054] Figure 10 Schematic diagram of the traction drive system model according to embodiment 2 of the present invention;

[0055] Figure 11 This is a potential distribution diagram of the power supply line cross section according to embodiment 2 of the present invention;

[0056] Figure 12 This is the magnetic field distribution diagram of the 83000000ns transformer of Example 2 of the present invention;

[0057] Figure 13 2 is a distribution diagram of magnetic flux and magnetic induction field according to Example 2 of the present invention;

[0058] Figure 14 2 is a distribution diagram of magnetic flux and magnetic induction field according to Example 2 of the present invention;

[0059] Figure 15 1 is a graph showing three-phase induced voltage and core loss according to embodiment 2 of the present invention;

[0060] Figure 16 1 is a graph showing three-phase induced voltage and core loss according to embodiment 2 of the present invention;

[0061] Figure 17 This is the antenna frequency sweep curve of Example 2 of the present invention;

[0062] Figure 18 This is a graph of the antenna gain Gain Total according to Example 2 of the present invention;

[0063] Figure 19 This is a Radiation Pattern diagram of Example 2 of the present invention. DETAILED DESCRIPTION

[0064] The following is a further detailed description of a rail transit system electromagnetic simulation method, device, equipment and storage medium provided by the present invention in conjunction with the accompanying drawings and specific embodiments. However, this should not be understood as the scope of the above-mentioned subject matter of the present invention being limited to the following embodiments. All technologies implemented based on the content of the present invention belong to the scope of the present invention. The advantages and features of the present invention will become clearer with reference to the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0065] Example 1

[0066] This embodiment provides a specific implementation of a rail transit system electromagnetic simulation method. Starting from the overall rail transit system, it analyzes its main interference sources, sensitive equipment, and coupling paths, establishes a finite element simulation model of the primary research object, and applies excitation to the traction power supply system, traction drive system, and communication system models, solving for the electromagnetic field simulation distribution of each system. Results include the contact line potential distribution of the traction power supply system, the induced magnetic field distribution of the transformer, the magnetic field strength and flux linkage distribution around the permanent magnet motor, and the antenna radiation field. The method described in this embodiment enables more convenient and simple observation of the electromagnetic field distribution in three-dimensional space, early prediction of electromagnetic interference, and more cost-effective evaluation.

[0067] In a first aspect, an embodiment of the present application provides a rail transit system electromagnetic simulation method, comprising the following steps:

[0068] S1. Establish a geometric entity model of the rail transit system, the geometric entity model includes a traction power supply system model, a traction drive system model, and a communication system model;

[0069] S2. Determining the parameters of the geometric solid model, and establishing a finite element simulation model based on the parameters;

[0070] S3. Setting port excitation for the finite element simulation model, including voltage, current and frequency parameters;

[0071] S4. Using three-dimensional electromagnetic field simulation software, based on the finite element simulation model and the port excitation, obtain the electromagnetic field distribution of the rail transit system and analyze the coupling path between the interference source and the sensitive equipment.

[0072] In this implementation, a comprehensive geometric solid model of the rail transit system is established to ensure the comprehensiveness and accuracy of the simulation. This allows subsequent simulations to fully reflect the actual electromagnetic behavior of the system, enhancing the reliability and practicality of the simulation.

[0073] In some embodiments, the traction power supply system model includes a pantograph, a contact network, a transmission line, a transformer, a converter, an inverter, and a traction motor; and performing electromagnetic simulation on the traction power supply system model includes the following steps:

[0074] S111. The overhead line obtains high-voltage power through the pantograph, and the transformer converts the high-voltage power into low-voltage AC power;

[0075] S112. The converter converts the low-voltage AC power into DC power, and the inverter converts the DC power into AC power with adjustable frequency and amplitude, which is ultimately supplied to the traction motor;

[0076] S113. Set port excitation for the transmission line in the traction motor to simulate the impact of the transmission line on the electromagnetic field distribution of the rail transit system.

[0077] In the above implementation, the traction power supply system is specifically simulated, which can accurately simulate the power collection, conversion and supply process, thereby more accurately evaluating the performance of the system in actual operation and improving the efficiency of system design and maintenance.

[0078] In some embodiments, the transmission line in step S113 uses a three-core cable to simulate the impact of the multi-layer structure of the three-core cable on the electromagnetic field distribution of the rail transit system.

[0079] In the above implementation, by simulating the impact of the multi-layer structure of the three-core cable on the electromagnetic field, an in-depth understanding of cable design and material selection is provided, which helps to optimize the electromagnetic compatibility and safety of the cable.

[0080] In some embodiments, the traction drive system model includes a transformer, a three-phase asynchronous motor, a converter, and an inverter; performing electromagnetic simulation on the traction drive system model includes the following steps:

[0081] S121 sets the transformer material, coil turns, current and cross-sectional current density; obtain low voltage AC power through the transformer;

[0082] S122. Using a converter to convert the AC power output of the transformer into DC power, and then converting the DC power into AC power with adjustable frequency and amplitude;

[0083] S123. Simulate the physical parameters of the stator winding and the magnetic field distribution of the rotor of the three-phase asynchronous motor, set the port excitation for the three-phase asynchronous motor, and simulate the electromagnetic field distribution of the three-phase asynchronous motor after being subjected to the port excitation.

[0084] In this implementation, detailed simulation of the electromagnetic characteristics of the traction drive system, particularly at the transformer, converter, and motor levels, enables system designers to accurately predict and adjust system performance under various operating conditions.

[0085] In some embodiments, the converter described in S122 is a four-quadrant IGBT converter.

[0086] In the above implementation, the use of a four-quadrant IGBT converter enhances the functionality of the converter, allowing for more flexible and efficient power conversion, adapting to a wider range of operating requirements, and thereby improving the overall performance and energy efficiency of the system.

[0087] In some embodiments, the communication system model is modeled based on a microstrip patch antenna; the microstrip patch antenna uses FR-4 as a dielectric substrate material with a relative dielectric constant of 4.4.

[0088] In the above implementation, by using a specific material FR-4 as the dielectric substrate of the microstrip patch antenna, the antenna design is optimized, its working efficiency and signal quality are improved, and the reliability and stability of the communication system are ensured.

[0089] In a second aspect, an embodiment of the present application provides an electromagnetic simulation device for a rail transit system, the simulation device comprising:

[0090] A model building unit, configured with interfaces and tools for creating and editing geometric entity models of rail transit systems, including traction power supply system models, traction drive system models, and communication system models;

[0091] a parameter determination unit, configured to receive the geometric solid model output from the model building unit, and determine various parameters of the model, thereby establishing a corresponding finite element model;

[0092] Excitation configuration unit, used to set the port excitation of the finite element model, including setting voltage, current and frequency parameters;

[0093] The simulation execution unit is equipped with 3D electromagnetic field simulation software, which is used to perform simulation operations based on the set finite element model and port excitation to obtain the electromagnetic field distribution of the rail transit system and analyze the coupling path between interference sources and sensitive equipment;

[0094] The result analysis unit is used to receive the electromagnetic field data output by the simulation execution unit and perform data analysis and visualization.

[0095] In the above implementation, the system device provides a one-stop solution, from model establishment to parameter determination, excitation configuration, simulation execution and result analysis, providing users with efficient and accurate simulation tools to support complex rail transit electromagnetic simulation needs.

[0096] In a third aspect, an embodiment of the present application provides a computer device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the method for electromagnetic simulation of a rail transit system is implemented.

[0097] In the above implementation, by implementing the simulation method on a computer device, the method can be widely deployed on different hardware, thereby enhancing the accessibility and flexibility of the method.

[0098] In a fourth aspect, an embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, a method for electromagnetic simulation of a rail transit system is implemented.

[0099] In the above implementation, the computer-readable storage medium provides a convenient way to distribute and deploy the simulation program, ensuring that different users can easily implement the simulation method on their devices, thereby promoting the popularization and application of the technology.

[0100] Example 2

[0101] This embodiment shows a specific implementation method of a rail transit system electromagnetic simulation method. Figure 2 As shown in the figure, a geometric solid model of the rail transit system is first established to ensure its accuracy and practicality. Based on the actual data measured on the geometric solid model of the rail transit system, simulation parameters of various devices are set, including current and voltage excitations, to simulate the performance of the devices in real working environments. These excitations reflect the electromagnetic field conditions during device operation and provide the necessary input data for finite element simulation. Subsequently, in the simulation module, the electromagnetic field distribution under different train operating conditions is systematically simulated and measured. This approach allows for the effective analysis of the electromagnetic field around the system in both static and dynamic scenarios, and the intuitive observation of the impact of interference sources such as pantograph arcs on the electromagnetic field.

[0102] Compared to traditional on-site measurements, the simulation method described in this embodiment reduces the consumption of manpower and material resources while avoiding the limitations of numerical calculations based on assumptions under laboratory conditions. Through simulations supported by actual measurement data, the complex environmental factors and special operating conditions of train operation can be more comprehensively considered, providing more accurate electromagnetic field analysis results. This not only enhances the practicality of the simulation but also enables the precise simulation of the transient electromagnetic field distribution of high-speed trains, thus providing a scientific basis for the design and optimization of rail transit systems.

[0103] Specifically, the following steps are included:

[0104] S1. Establishing a geometric entity model of the rail transit system

[0105] The geometric entity model of the rail transit system includes the traction power supply system model, the traction drive system model and the communication system model.

[0106] S11. Traction power supply system model

[0107] The traction power supply system, the core power source of high-speed trains, consists of a substation and traction network. The substation includes high-voltage circuit breakers, transformers, and monitoring equipment. However, the low-frequency conductive field strength caused by the harmonics of high-voltage equipment is generally below 20 MHz, which does not interfere with broadcast FM, communications, and other equipment. The traction network, consisting of the catenary, rails, return lines, and earth return lines, is a major source of interference in rail transit systems.

[0108] In this embodiment, the traction power supply system model includes a pantograph, catenary, transmission lines, transformers, a converter, two inverters, and four traction motors. When operation starts, the pantograph on the roof slides to draw power from the catenary, which is typically 25kV and 50Hz. The power transmission path is as follows: Figure 7 As shown in the figure, electricity is first transmitted to the transformer and converted to 900V AC. It is then processed by the converter and inverter to convert it into adjustable AC between 0 and 1287V before being supplied to the traction motor. This series of power conversion and regulation ensures a continuous and stable power supply for high-speed trains.

[0109] In this embodiment, a three-core cable is used as an example to simulate the transmission line in the traction power supply system model. Figure 3 As shown in the figure, three-core cables are suitable for the structure of power cables in the transmission circuits of rail transit systems. They receive voltage from substations and are used for power transmission. The rated voltage of the transmission line is 25kV and the frequency is approximately 50Hz. Therefore, the selected cable is an AC polyethylene-insulated, steel-tape-armored, PVC-sheathed three-core power cable with a rated voltage of 35kV and below, which belongs to the category of medium and low voltage power cables.

[0110] like Figure 8As shown, the three-core cable utilizes a multi-layer design to enhance its performance and safety. The outer layer, consisting of a PVC outer jacket and steel tape armor, primarily protects the three-core cable from external environmental factors such as mechanical damage and chemical corrosion. The inner layer, comprising a PVC liner and a non-woven fabric cable wrap, provides necessary mechanical cushioning and padding, preventing dust and small particles from intruding into the three-core cable. The three-core cable also incorporates multiple shielding layers to protect against electromagnetic interference (EMI), including a copper tape shield, an outer shield, and an XLPE insulation shield. The copper tape shield directly blocks external EMI, while the outer shield and XLPE layers further enhance this performance. The XLPE layer is specifically designed to prevent leakage. The inner shield prevents electromagnetic signal leakage within the three-core cable. The core of the three-core cable is the conductor layer, whose primary function is to efficiently and stably transmit electrical signals. This meticulously designed multi-layer structure enables the three-core cable to adapt to diverse and complex environmental conditions, ensuring a stable power supply and clear signal transmission within rail transit systems.

[0111] Specifically, the dimensions and materials of the three-core cable are shown in Table 1:

[0112] Table 1 YJV22-21 / 35kV size parameters and material list

[0113]

[0114] S12. Traction drive system model

[0115] The traction drive system model includes a transformer, a three-phase asynchronous motor, a converter and an inverter.

[0116] S121. Transformer

[0117] like Figure 4 As shown, the transformer uses an iron core and copper coil made of nonlinear magnetic material, which is diamagnetic and has a relative magnetic permeability of 0.99990. In addition, it adopts an oil-immersed design, in which the relative magnetic permeability of the transformer oil is close to 1, to enhance insulation and heat dissipation efficiency. The technical parameters of the transformer are:

[0118] Low voltage side: 57 turns, 144.3A current per turn, 8225.1A total current, cross-sectional current density: 1.27×10 6 A / m 2 ;

[0119] High voltage side: 1425 turns, 5.77A per turn, 8222.25A total turn current, cross-sectional current density: 9.126×10 5 A / m 2 .

[0120] S122. Converter

[0121] like Figure 5 As shown in FIG, the converter structure includes a four-quadrant IGBT converter and a PWM inverter, which can convert AC power into DC power and then convert DC power into three-phase AC power with adjustable frequency and amplitude.

[0122] like Figure 9 As shown in the figure, in the four-quadrant IGBT converter, U1 and U2 on the left are the two-phase components of the four-quadrant converter. U1 and U2 are composed of two controllable switching elements (such as IGBT or thyristor), which are alternately turned on to control the direction and intensity of the current. N Converted to DC voltage U d On the right, U3, U4, and U5 represent the three phases of the three-phase inverter. Each contains two controllable switching elements, which regulate the output three-phase AC voltage by controlling the switching state. The middle capacitor C1 stores energy and provides a smooth DC voltage, eliminating AC components and ensuring DC voltage stability, acting as a filter. C2 and L2 are connected in series to absorb the second harmonic component in the circuit, reducing interference with the external power grid and improving the quality of the output current.

[0123] S123. Three-phase asynchronous motor

[0124] like Figure 6 As shown, this embodiment uses a three-phase asynchronous motor of model 1TB2019, with a rated power of 562kW and an insulation grade of Class 200, i.e., a temperature resistance of 200°C. It has the advantages of high torque, high efficiency, and low consumables. Its structure is divided into the following parts:

[0125] (1) The stator core is made of DW465-50 silicon steel sheets. The material is non-linear, the insulation grade is 200, and it can withstand high temperatures.

[0126] (2) The stator core is installed in the machine base. The stator winding is made of copper material. The three-phase windings are 120 degrees apart. The physical quantities that can be calculated or measured include the instantaneous value of phase voltage, instantaneous value of current, instantaneous value of magnetic flux, etc.

[0127] (3) The rotor is a permanent magnet. The rotating magnetic field around the stator and the constant magnetic field of the rotor attract each other, thus completing the attraction. Otherwise, it cannot be attracted. There is no winding on the rotor.

[0128] S13. Communication system model

[0129] Communication systems generally use rod antennas, coupled antennas, and microstrip antennas. In this embodiment, the communication system model uses a microstrip antenna that operates efficiently in the 900 MHz frequency band as an example. In some embodiments, a microstrip patch antenna is used. This microstrip patch antenna uses FR-4 as the dielectric substrate material, with a relative dielectric constant of 4.4, enabling the antenna to achieve maximum efficiency in the operating frequency range near 900 MHz. The approximate patch size is calculated based on the empirical formula for microstrip patch antennas. The length and width calculation formula is as follows:

[0130]

[0131] Where W is the width of the microstrip patch antenna, L is the length of the microstrip patch antenna, and ε r is the relative dielectric constant of the medium, ε e is the effective dielectric constant, c is the speed of light 3×10 8 m / s,f r That is the frequency of the center band. After calculation, the length is about 30mm and the width is half of the length.

[0132] Furthermore, the microstrip patch antenna model design takes into account clearances from surrounding structures, typically leaving approximately 2mm of space to reduce electromagnetic interference between adjacent components. The antenna gap is kept within 0.5mm to optimize the radiation pattern and prevent energy leakage. To further optimize antenna performance and meet miniaturization requirements, a coaxial probe feed method is employed. This feeding method not only supports efficient power transmission but also helps maintain the compactness of the overall antenna design.

[0133] S2. Set the basic parameters of each model

[0134] The basic parameters are the material properties of each model obtained in the previous steps, including antenna dimensions, dielectric material and relative permittivity, and the rated power of the three-phase asynchronous motor. After selection and calculation, these basic model parameters serve as input to the simulation software.

[0135] S3. Set port stimulus

[0136] The method for setting the port excitation is:

[0137] For the traction power supply system model, the center voltage of the transmission line is set to 25kV, the peripheral voltage is 0V, and a 50Hz sine function is selected as the excitation.

[0138] Figure 10The transformer of the traction drive system model is shown, with the location and characteristics of the cross section detailed. The cross section is perpendicular to the axis of the transformer and parallel to the winding plane, which makes it easier to understand the direction and target area of ​​the cut. Enter the transformer technical parameters in step S121. During the simulation, the reference coordinate system is first moved to the center line of the selected coil, and then the cut is made in the in plane cross section. The cut body is separated by the separate body operation, and the ports on one side are deleted, leaving only the ports on the other side for current excitation. When applying current excitation, the direction is specified and the current is loaded to the coil. After loading is completed, the current needs to be matrixed by defining parameters so that matrix operations can be used to simulate the current flow. Finally, set the parameters of the simulation analysis, including the calculation step size and the start and end times to complete the Analysis Setup step.

[0139] When setting up motor port excitation, use Maxwell software to define a band and place the moving object within the band to select forward rotation. Similar to the transformer setup, excitation is applied to each of the three phase windings. The current frequency of the winding group is maintained at approximately 50 Hz, and core losses are set to complete the system inspection.

[0140] In HFSS, the traction drive system converter model and the communication system antenna model were driven in DrivenModel mode. In this mode, the spatial domain is defined as a radiation boundary, allowing electromagnetic waves to propagate freely in space. The ground is treated as a good conductor, and excitation is applied to the junction of the coaxial feeder and the ground. A frequency sweep with a center frequency of 900 MHz is performed to determine the range and intensity of the radiation. After verification, the simulation is run.

[0141] ANSYS software provides an intuitive graphical user interface and result display interface, making it easier for users to perform geometric modeling and result analysis. Compared to SIMULINK, ANSYS can provide a more intuitive graphical user interface and result display interface, making it easier for users to perform geometric modeling and result analysis. At the same time, although finite element simulation software such as COMSOL Multiphysics and Abaqus support multi-physics field coupling, their electromagnetic simulation modules are not as efficient and accurate as ANSYS when dealing with complex electromagnetic problems. In addition, unlike other software that is limited to device-level analysis, the Maxwell and HFSS modules in ANSYS can be used to simultaneously study the low-frequency electromagnetic field distribution and high-frequency radiation effects at the device and system levels, intuitively displaying the electromagnetic field distribution in the three-dimensional space around the rail transit system.

[0142] S4. Use the 3D electromagnetic field simulation module to obtain the electromagnetic field distribution of the rail transit system

[0143] Starting with the rail transit system as a whole, the team analyzed its main interference sources, sensitive equipment, and coupling paths, established finite element simulation models of the primary research objects, and applied excitation to the traction power supply system, traction drive system, and communication system models, solving for the electromagnetic field simulation distribution of each system. Results included the contact line potential distribution of the traction power supply system, the induced magnetic field distribution of the transformer, the magnetic field intensity and flux linkage distribution around the permanent magnet motor, and the antenna radiation field. This allows for more convenient and simple observation of the electromagnetic field distribution in three dimensions, enabling early prediction of electromagnetic interference and achieving more cost-effective assessments.

[0144] Simulation results analysis:

[0145] Distribution of electromagnetic field in power supply line: The positions of multiple conductors in the traction system are basically fixed. The center voltage of the transmission line is 25kV, the peripheral voltage is 0V, and the cross-sectional potential distribution is as follows: Figure 11 .

[0146] Figure 11 The maximum field strength in this model does not occur at the center of the circle, but rather at the outer radius of the inner conductor. Under this model, the maximum value reaches 4,586,500 V / m. The breakdown field strengths of the protective materials, polyvinyl chloride (PVC), and polyethylene (PE), are 35-50 MV / m and 20-35 MV / m, respectively, which are sufficient to withstand the pressure and prevent dielectric breakdown. Furthermore, changes in the thickness of the protective material and the arrangement of the material layers significantly affect the field strength, leading to strict configuration and quality requirements for high-voltage transmission lines used in engineering practice.

[0147] Transient magnetic field distribution of transformer: The results of the transformer at two moments are intercepted from the simulation process as follows Figure 12 Although the maximum magnetic field strength can reach Tera level, Figure 12 It can be seen that the magnetic field strength is higher near the winding, but the influence of the magnetic field decays rapidly as the distance increases. This is determined by Maxwell's equations, especially near point or line sources, where the magnetic field strength usually decays rapidly as the distance increases. In addition, the density of the magnetic field lines (that is, the number of magnetic lines of force per unit area) is directly proportional to the strength of the magnetic field, given by Figure 12 As you can see, the magnetic flux lines of the winding are very sparse, and the impact range is very limited. Therefore, as long as the transformer oil is properly selected and the casing is well shielded, it will not have any further impact on the external system.

[0148] Traction motor magnetic field distribution: after operation Figure 13 , which is the distribution diagram of the magnetic flux induction field, which is the magnetic flux density (A / m) under the given time (Time = -0.04s) and speed (Speed ​​= 4.5m / s) conditions. 2 ) along the horizontal axis (x-axis) is a description of the magnetic flux passing through a plane. Figure 14, which is the magnetic induction field distribution diagram, and the different color areas in the diagram show the magnetic induction intensity at that point. The three-phase induced voltage curve is obtained Figure 15 and loss Figure 16 Here we select the result of 0.04s. The maximum magnetic induction intensity of 2.62T appears at the edge of the winding. In the centimeter-level space nearby, the induction intensity drops rapidly to 10 -4 T, so for traction motors, the electromagnetic characteristics optimization plan also focuses on the material selection and metal shielding level of core components, and no longer considers the impact on the surrounding space.

[0149] Antenna model gain: The antenna sweep frequency curve and gain size are obtained by simulation, such as Figure 17 The antenna sweep frequency curve, with frequency as the horizontal axis and gain as the vertical axis, represents the antenna working load at different frequencies; Figure 18 This is a graph showing how antenna gain changes with spatial angle. Color coding indicates different gain values, with brighter colors indicating higher gain and darker colors indicating lower gain. This shows how energy is distributed across the entire solid angle. Figure 19 It is a three-dimensional polarization diagram of antenna radiation, which shows the radiation pattern of the antenna and characterizes the directional characteristics of the electromagnetic waves emitted or received by the antenna.

[0150] It can be read that the resonant frequency obtained by sweeping the 800-1000MHz wave is approximately 928MHz. Near the center frequency, it belongs to spatial radiation, and the radiation is maximum in the tangent direction of the diagonal line of the positive semi-axis of the Z and X coordinate axes. Since the transmission distance of electromagnetic waves is proportional to the antenna gain, the antenna gain used by directional base stations is greater and the influence range is wider.

[0151] Taking into account the transmission loss caused by the atmospheric absorption of waves and polarization direction errors, the loss formula for the antenna line-of-sight transmission path within 20m and within the range of 20m-5km is given:

[0152] L bf1 =32.44+10lgr+20lgf

[0153] L bf2 =42.6+26lgr+20lgf

[0154] In the above two formulas, L bf1 and L bf2 They are the free space loss values ​​within 20m and in the range of 20m-5km, respectively. f represents the frequency in MHz, and r represents the horizontal distance between the field point and the center of the antenna, calculated in km.

[0155] exist Figure 17In the simulation shown, the electromagnetic wave resonant frequency of the 900MHz microstrip patch antenna is about 928MHz. Near the center frequency, the return loss at the resonance point is the largest, but it is only -11.8dB. In the 30% humidity environment, the potentials of the high-voltage end, the ground end, and their surroundings are significantly improved, and the maximum electric field strength can reach 2×10 3 For a high-speed train with a speed of 350 km / h, the initial arc loading has a maximum magnetic field strength of about 5.3×10 -9 T, and when the arc burns most violently, the magnetic field strength can reach 5.2×10 -3 T, the magnetic density curve amplitude at different instants or distances is different, and the magnetic flux of the arc steady-state combustion can reach up to 2.5Wb / m 2 .

[0156] In actual projects, antenna equipment of rail transit systems is often arranged next to sensitive equipment or installed on the ground. Therefore, the electromagnetic field strength generated by the antenna at a certain point in space is the sum of the direct field strength and the secondary field strength formed by reflection.

[0157] In summary, the interference sources modeled in this embodiment, such as the power supply lines, transformers, antennas, and traction motors, can operate normally and conform to normal values ​​after modeling. While analyzing specific interference sources to achieve device-level analysis, the system-level analysis of the electromagnetic impact of the entire system on the external area is also completed. This is a new model establishment and simulation method, which provides a reference basis for the selection of electronic devices in rail transit systems and the formulation of electromagnetic compatibility standards.

[0158] Example 3

[0159] Example 3 provides a rail transit system electromagnetic simulation device, a computer device, and a computer-readable storage medium for implementing a rail transit system electromagnetic simulation method described in the present invention.

[0160] An electromagnetic simulation device for a rail transit system, comprising the following units:

[0161] A model building unit, configured with interfaces and tools for creating and editing geometric entity models of rail transit systems, including traction power supply system models, traction drive system models, and communication system models;

[0162] a parameter determination unit, configured to receive the geometric solid model output from the model building unit, and determine various parameters of the model, thereby establishing a corresponding finite element model;

[0163] Excitation configuration unit, used to set the port excitation of the finite element model, including setting voltage, current and frequency parameters;

[0164] The simulation execution unit is equipped with 3D electromagnetic field simulation software, which is used to perform simulation operations based on the set finite element model and port excitation to obtain the electromagnetic field distribution of the rail transit system and analyze the coupling path between interference sources and sensitive equipment;

[0165] The result analysis unit is used to receive the electromagnetic field data output by the simulation execution unit and perform data analysis and visualization.

[0166] A computer device comprises a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the electromagnetic simulation method for a rail transit system according to the present invention is implemented.

[0167] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the electromagnetic simulation method for a rail transit system according to the present invention is implemented.

[0168] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware.

[0169] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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 specification.

[0170] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A rail transit system electromagnetic simulation method, characterized in that: The following steps are involved: S1. Establishing a geometric entity model of the rail transit system, the geometric entity model includes a traction power supply system model, a traction drive system model and a communication system model; S2. Determine the parameters of the geometric solid model, and establish a finite element simulation model according to the parameters; S3. Setting port excitation for the finite element simulation model, including voltage, current and frequency parameters; S4. Using three-dimensional electromagnetic field simulation software, based on the finite element simulation model and the port excitation, the electromagnetic field distribution of the rail transit system is obtained, and the coupling path between the interference source and the sensitive equipment is analyzed.

2. The electromagnetic simulation method for a rail transit system according to claim 1, characterized in that: The traction power supply system model includes a pantograph, a contact network, a transmission line, a transformer, a converter, an inverter and a traction motor; and performing electromagnetic simulation on the traction power supply system model includes the following steps: S111. The overhead line obtains high-voltage power through the pantograph, and the transformer converts the high-voltage power into low-voltage AC power; S112. The converter converts the low voltage AC power into DC power, and the inverter converts the DC power into AC power with adjustable frequency and amplitude, which is finally supplied to the traction motor; S113. Setting port excitation for the transmission line in the traction motor to simulate the influence of the transmission line on the electromagnetic field distribution of the rail transit system.

3. The electromagnetic simulation method for a rail transit system according to claim 2, characterized in that: In step S113, the transmission line adopts a three-core cable, and the influence of the multi-layer structure of the three-core cable on the electromagnetic field distribution of the rail transit system is simulated.

4. The electromagnetic simulation method for a rail transit system according to claim 2, characterized in that: The traction drive system model includes a transformer, a three-phase asynchronous motor, a converter and an inverter; performing electromagnetic simulation on the traction drive system model includes the following steps: S121. Set the transformer material, coil turns, current and cross-sectional current density; obtain low voltage alternating current through the transformer; S122. Using a converter to convert the AC power output by the transformer into DC power, and then converting the DC power into AC power with adjustable frequency and amplitude; S123. Simulate the physical parameters of the stator winding and the magnetic field distribution of the rotor of the three-phase asynchronous motor, set the port excitation for the three-phase asynchronous motor, and simulate the electromagnetic field distribution of the three-phase asynchronous motor after being excited by the port.

5. The electromagnetic simulation method for a rail transit system according to claim 1, characterized in that: The converter described in S122 adopts a four-quadrant IGBT converter.

6. The electromagnetic simulation method for a rail transit system according to claim 1, characterized in that: The communication system model is modeled according to a microstrip patch antenna; the microstrip patch antenna uses FR-4 as a dielectric substrate material, and the relative dielectric constant is 4.

4.

7. An electromagnetic simulation device for a rail transit system, characterized in that: The simulation device comprises: A model building unit, configured with interfaces and tools, for creating and editing a geometric entity model of a rail transit system, including a traction power supply system model, a traction drive system model, and a communication system model; A parameter determination unit, used for receiving the geometric solid model output from the model building unit, and determining various parameters of the model, and then establishing a corresponding finite element model; An excitation configuration unit, used to set port excitation for the finite element model, including setting voltage, current and frequency parameters; A simulation execution unit, which is loaded with three-dimensional electromagnetic field simulation software and is used to perform simulation operations based on the set finite element model and port excitation to obtain the electromagnetic field distribution of the rail transit system and analyze the coupling paths of interference sources and sensitive equipment; The result analysis unit is used to receive the electromagnetic field data output by the simulation execution unit and perform data analysis and visualization.

8. A computer device, characterized in that: The computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, a rail transit system electromagnetic simulation method as described in any one of claims 1 to 6 is implemented.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method for electromagnetic simulation of a rail transit system as claimed in any one of claims 1 to 6 is implemented.

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