A train interference analysis method and device and a storage medium

Abstract

The application discloses a train interference analysis method and device and a storage medium, and relates to the field of train interference analysis. In the scheme, the complex permittivity under different frequencies is measured in advance to obtain a corresponding relationship between the complex permittivity and the frequency, so that when electromagnetic analysis is performed on the whole train, the target complex permittivity corresponding to the current simulation frequency in the corresponding relationship is used instead of the complex permittivity provided in the existing literature, thereby avoiding the problem that the cited complex permittivity cannot be verified. Furthermore, the accuracy of electromagnetic testing on the whole train is higher by using the pre-measured complex permittivity. In addition, when electromagnetic analysis is performed on the whole train in the application, an electromagnetic simulation model is established, which is an entity simulation model based on the vehicle body structure. Compared with the simplified electromagnetic model commonly used in the prior art, the simulation result obtained is closer to the actual application scenario, so that the reference significance of the simulation result is greater and the value is higher.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of train interference analysis, and in particular to a train interference analysis method and device and a storage medium. BACKGROUND

[0002] At present, carbon fiber composite materials (composite materials) have been widely used in lightweight vehicle body manufacturing, covering parts, components to whole vehicle structure, but the electrical conductivity of composite materials is much lower than that of traditional metal materials, and has obvious anisotropy. The significant difference in material properties brings difficulties to the electromagnetic compatibility analysis and evaluation of the whole vehicle. Compared with the welding structure of the metal vehicle body, the composite material vehicle body assembly adopts a large number of glue riveting and plug-in processes for the connection of composite material-metal, composite material-composite material and metal-metal heterogeneous materials, and the connection interface exists in the discontinuous electrically connected state. When electrical and electronic equipment, wire slots / pipes and composite material vehicle body are integrated, the influence mechanism of these connection structures on the conduction and radiation interference of the interference source is not clear, which leads to the inability to effectively take the EMC design means such as filtering, shielding and lapping grounding to carry out EMC design on the composite material vehicle body.

[0003] Therefore, it is an urgent problem for those skilled in the art to provide a train interference analysis method to analyze the interference of a vehicle body including composite material structure. SUMMARY

[0004] The purpose of the present application is to provide a train interference analysis method, device and storage medium, which pre-measures the complex permittivity at different frequencies to obtain the corresponding relationship of complex permittivity-frequency, so as to use the target complex permittivity corresponding to the current simulation frequency in the corresponding relationship when performing electromagnetic analysis on the whole vehicle, instead of using the complex permittivity provided in the existing literature, thereby avoiding the problem that the quoted complex permittivity cannot be verified, and the accuracy of electromagnetic testing on the whole vehicle is higher. In addition, when performing electromagnetic analysis on the whole vehicle, the established electromagnetic simulation model is an entity simulation model based on the vehicle body structure. Compared with the simplified electromagnetic model commonly used in the prior art, the simulation result obtained is closer to the actual application scenario, so that the reference significance of the simulation result is greater and the value is higher.

[0005] To solve the above technical problems, the present application provides a train interference analysis method, comprising:

[0006] Pre-measuring the complex permittivity corresponding to the current frequency at different frequencies to obtain the corresponding relationship of complex permittivity-frequency, wherein the corresponding relationship at least includes nonlinear data of the complex permittivity changing with frequency;

[0007] establishing an entity electromagnetic simulation model according to a train body structure, the train body structure comprising at least an entity composite structure, an entity metal structure and an entity lap joint structure for connecting the entity composite structure and the entity metal structure;

[0008] determining a target complex permittivity corresponding to the current simulation frequency according to the current simulation frequency and the corresponding relationship;

[0009] introducing a preset interference source and performing interference response analysis on the train body according to the target complex permittivity and the entity electromagnetic simulation model.

[0010] Preferably, the preset interference source comprises a direct current interference source, and / or an alternating current interference source with a frequency lower than a preset value, and / or an alternating current interference source with a frequency higher than the preset value.

[0011] Preferably, the preset interference source comprises a stray current, and / or a traction inverter interference signal, and / or a lightning strike waveform.

[0012] Preferably, introducing a preset interference source and performing interference response analysis on the train body according to the target complex permittivity and the entity electromagnetic simulation model comprises:

[0013] when the direct current interference source or the alternating current interference source with a frequency lower than the preset value is introduced, performing interference response analysis on the train body according to the target complex permittivity and an entity electromagnetic simulation model of a first structure;

[0014] when the alternating current interference source with a frequency higher than the preset value is introduced, performing interference response analysis on the train body according to the target complex permittivity and an entity electromagnetic simulation model of a second structure;

[0015] wherein the train body structure included in the first structure is more complex than the train body structure included in the second structure.

[0016] Preferably, the entity composite structure is directly or indirectly connected with the grounding net through rivets or metal components.

[0017] Preferably, the way of measuring the complex permittivity is:

[0018] using a three-electrode non-contact method to establish a corresponding equivalent circuit with the to-be-measured composite material as a measurement electrode;

[0019] calculating the complex permittivity of the to-be-measured composite material according to the equivalent circuit.

[0020] Preferably, the structure of the to-be-measured composite material comprises a circular ring component and a cylindrical component, the circular ring component is sleeved on the outer layer of the cylindrical component, a gap is arranged between the circular ring component and the cylindrical component, and a gap is arranged between the outer layer of the circular ring component and the guard electrode.

[0021] Preferably, the complex permittivity of the measured composite material is calculated according to the equivalent circuit, comprising:

[0022] A plurality of equivalent equations are constructed according to the air equivalent circuit when the measured composite material is not loaded, the gap equivalent circuit when the measured composite material is loaded, and the equivalent circuit of the gap and the measured composite material when the measured composite material is loaded.

[0023] The inductance, capacitance and resistance of the measured composite material are calculated according to a plurality of the equivalent equations.

[0024] The complex permittivity of the measured composite material is calculated according to the inductance, capacitance and resistance of the measured composite material.

[0025] Preferably, the equivalent equation comprises:

[0026] The first equivalent equation is:

[0027] The second equivalent equation is:

[0028] The third equivalent equation is:

[0029] The fourth equivalent equation is:

[0030] Wherein, Y g is the air admittance when the measured composite material is not loaded, Y3 is the admittance of the gap between the measured composite material and the protective electrode after the measured composite material is loaded, C tg is the capacitance of the air with the same size as the measured composite material, R3 is the air resistance when the measured composite material is not loaded, C3 is the air capacitance when the measured composite material is not loaded, Y is the admittance of the gap and the measured composite material after the measured composite material is loaded, Y1 is the admittance of the measured composite material, and Δ is the error amount caused by the edge and ground capacitance effect.

[0031] To solve the above technical problems, the application further provides a train interference analysis device, comprising:

[0032] A memory for storing a computer program;

[0033] A processor for implementing the steps of the train interference analysis method as described above when storing the computer program.

[0034] To solve the above technical problems, the application further provides a computer readable storage medium, wherein the computer readable storage medium stores a computer program, and the computer program is executed by a processor to implement the steps of the train interference analysis method as described above.

[0035] The application provides a train interference analysis method and device and a storage medium, and relates to the field of train interference analysis. In the scheme, the complex permittivity under different frequencies is measured in advance to obtain the corresponding relationship between the complex permittivity and the frequency, so that when the whole vehicle is subjected to electromagnetic analysis, the target complex permittivity corresponding to the current simulation frequency in the corresponding relationship is used instead of the complex permittivity provided in the existing literature, thereby avoiding the problem that the cited complex permittivity cannot be verified. Furthermore, the accuracy of electromagnetic testing of the whole vehicle is higher by using the pre-measured complex permittivity. In addition, when the whole vehicle is subjected to electromagnetic analysis in the application, the electromagnetic simulation model established is an entity simulation model based on the vehicle body structure. Compared with the simplified electromagnetic model commonly used in the prior art, the simulation result obtained is closer to the actual application scenario, so that the simulation result has greater reference significance and higher value. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the prior art and embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0037] Figure 1 A flowchart of a train interference analysis method provided by the present application is shown in the figure;

[0038] Figure 2 A partial schematic view of a vehicle body structure provided by the present application is shown in the figure;

[0039] Figure 3 An electrode sample arrangement for measuring complex permittivity provided by the present application is shown in the figure;

[0040] Figure 4a A sample conduction current distribution diagram when the measured composite material is complete is shown in the figure;

[0041] Figure 4b A sample conduction current distribution diagram when the measured composite material has a notch is shown in the figure;

[0042] Figure 4c A sample displacement current distribution diagram when the measured composite material has a notch is shown in the figure;

[0043] Figure 5a An equivalent circuit diagram when the measured composite material is not loaded is shown in the figure;

[0044] Figure 5b A first equivalent circuit diagram after the measured composite material is loaded is shown in the figure;

[0045] Figure 5c A second equivalent circuit diagram provided by the present application after loading the test composite material;

[0046] Figure 6a A measurement structure schematic provided by the present application;

[0047] Figure 6b An equivalent circuit diagram provided by the present application;

[0048] Figure 7 An impedance analyzer LCR three-element parallel equivalent circuit model schematic provided by the present application;

[0049] Figure 8 A structure block diagram of a train interference analysis device provided by the present application. DETAILED DESCRIPTION

[0050] The core of the present application is to provide a train interference analysis method, device and storage medium, the complex dielectric constant under different frequencies is measured in advance to obtain the corresponding relationship of complex dielectric constant-frequency, so as to use the target complex dielectric constant corresponding to the current simulation frequency in the corresponding relationship when the whole vehicle is electromagnetically analyzed, instead of using the complex dielectric constant provided in the existing literature, avoiding the problem that the quoted complex dielectric constant cannot be verified, and the accuracy of the electromagnetic test of the whole vehicle is higher; in addition, when the whole vehicle is electromagnetically analyzed, the electromagnetic simulation model established is an entity simulation model based on the vehicle body structure, compared with the simplified electromagnetic model commonly used in the prior art, the simulation result obtained is closer to the actual application scenario, so that the reference significance of the simulation result is greater and the value is higher.

[0051] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0052] Please refer to Figure 1 , Figure 1 A flowchart of a train interference analysis method provided by the present application, the method comprises:

[0053] S11: The complex dielectric constant corresponding to the current frequency is measured in advance at different frequencies to obtain the corresponding relationship of complex dielectric constant-frequency, and the corresponding relationship at least includes the nonlinear data of the complex dielectric constant changing with frequency;

[0054] Specifically, in the prior art, when simulating the vehicle body structure, the input complex permittivity is generally cited from the existing complex permittivity in the existing literature, and the source of these values is difficult to trace. In addition, the currently disclosed method for measuring the complex permittivity is generally a single frequency point, such as 1 kHz or several GHz in the microwave frequency band, and these measurement points are not the main frequency points of concern for electromagnetic compatibility of rail vehicles. In combination with the electromagnetic compatibility test of the whole rail vehicle, the frequency range starts from 150 kHz to several MHz, and the external electromagnetic radiation emission is easy to exceed the standard, therefore, the existing complex permittivity measurement has limitations in the application of composite rail vehicles.

[0055] Therefore, before simulating the vehicle body structure in the present application, the complex permittivity corresponding to the current frequency is first measured at different frequencies to obtain the corresponding relationship between the complex permittivity and the frequency, wherein the measured frequency is the frequency that the rail vehicle usually encounters in actual application, for example, a target frequency point that the rail vehicle usually encounters in actual application can be determined first, then a plurality of frequency points are taken within a frequency band range of 10%-30% of the center frequency with the target frequency point as the center, to obtain a plurality of complex permittivities respectively corresponding to the plurality of frequency points, and then the vehicle body structure is simulated based on the measured complex permittivity to obtain a more accurate simulation result.

[0056] The corresponding relationship can be a table or other forms, which is not limited in the present application.

[0057] S12: An entity electromagnetic simulation model is established according to the vehicle body structure of the train, and the vehicle body structure at least includes an entity composite structure, an entity metal structure, and an entity lap joint structure for connecting the entity composite structure and the entity metal structure;

[0058] It is considered that the mainstream method for simulating the vehicle body structure at present is to simplify the complex three-dimensional model, such as equivalent thin skin to zero-thickness geometric surface, and simplify the overall model to complete surface without lap joint structure, which has a large difference from the actual structure of the vehicle body, so that valuable results cannot be obtained from the simplified simulation model.

[0059] For example, the track backflow part penetrates into the vehicle body, for the composite material structure of the vehicle body, there are a large number of composite material piece-metal structure piece glue rivet connection structures, the composite material structure itself and the metal structure exist potential difference, there is potential electrochemical corrosion risk, and the stray current can aggravate such phenomenon, therefore, only through entity modeling and specific input of complex dielectric constant, the current distribution of the composite material piece-metal piece can be simulated, and the corrosion risk can be judged, and the conventional simplified model and simulation cannot be given. For another example, the handrail rod or the vehicle body accumulates static electricity, passengers can feel static discharge when getting on and off the vehicle, and many speed, temperature and other sensors are installed on the composite material bogie and other parts of the vehicle. Such sensors are easily affected by static discharge or overvoltage. The source of these working conditions includes high-speed running friction static electricity accumulation, converter harmonics, lightning working conditions and the like. The simplified model is also difficult to describe the static electricity or voltage distribution of the internal or space position of the entity structure, especially the installation position of these sensors. In summary, the simplified structure used in the simulation and the complex dielectric constant disclosed in the literature cannot obtain accurate reference results.

[0060] Specifically, the design idea of the present application is that when the interference response analysis is performed on the vehicle body including the composite material structure, the corresponding entity electromagnetic simulation model is established, so that the established simulation model is closer to the actual vehicle body structure. Therefore, when the entity electromagnetic simulation model of the vehicle body structure is established, the model at least includes the entity composite material structure (such as the composite material plate or the composite material beam in the Figure 2 , the entity metal structure and the entity lap joint structure of the lap joint metal structure and the composite material structure (such as the lap joint structure being a rivet or a glue layer), which cannot be equivalent to a simple non-thickness or non-interference idealized geometric surface or lap joint point. For specific reference Figure 2 , Figure 2 A part of the vehicle body structure is provided in the present application.

[0061] It should be noted that when the entity electromagnetic simulation model is established in the present application, the entity simulation model can be adjusted according to the user preset or user demand, for example, the entity simulation model is established in the local part to be concerned, and the simplified simulation model is established in the part not to be concerned. For example, in a specific embodiment, the entity simulation model is established for the whole structure of the vehicle body. In another embodiment, when the response of the lap joint structure is analyzed, the entity model is established for the composite material-metal lap joint structure and the parts directly connected with the lap joint structure which need to be analyzed in the vehicle, and the simplified model is established for the remaining part.

[0062] When the interference response of the train is analyzed by the entity electromagnetic simulation model in the present application, the entity composite material structure and the entity lap joint structure are considered, the influence of the entity lap joint structure in the composite material vehicle body is avoided, and the interference analysis of the train including the composite material structure is realized.

[0063] S13: determining a target complex permittivity corresponding to the current simulation frequency according to the current simulation frequency and the corresponding relationship;

[0064] Specifically, when modeling and analyzing the solid composite structure, the most critical parameter of the solid composite structure is the complex permittivity. Currently, the complex permittivity disclosed is usually used to analyze the composite structure. However, the source and accuracy of the complex permittivity disclosed in the prior art need to be further studied. Therefore, in the present application, the target complex permittivity corresponding to the current simulation frequency is determined according to the corresponding relationship between the measured complex permittivity and the frequency, and the target complex permittivity is used as a parameter needed in subsequent simulation, so as to improve the accuracy and reliability of the simulation results.

[0065] It can be seen that in the present application, when the solid electromagnetic simulation model including the composite structure is analyzed, the complex permittivity can be more accurate, and the accuracy of the interference analysis of the solid electromagnetic simulation model can be improved.

[0066] S14: introducing a preset interference source, and performing interference response analysis on the vehicle body according to the target complex permittivity and the solid electromagnetic simulation model.

[0067] Specifically, after the solid electromagnetic simulation model is constructed and the target complex permittivity needed in the solid electromagnetic simulation model is determined, a preset interference source is introduced to perform interference response analysis on the solid electromagnetic simulation model.

[0068] The specific implementation mode of the preset interference source can include but is not limited to a direct current interference source, and / or an alternating current interference source with a frequency lower than a preset value, and / or an alternating current interference source with a frequency higher than a preset value. Further, the specific implementation mode of the preset interference source can include but is not limited to a stray current, and / or a traction inverter interference signal, and / or a lightning waveform, etc., or other implementation modes, which are not limited herein.

[0069] As a preferred embodiment, introducing a preset interference source, and performing interference response analysis on the vehicle body according to the target complex permittivity and the solid electromagnetic simulation model, includes:

[0070] When a direct current interference source or an alternating current interference source with a frequency lower than a preset value is introduced, interference response analysis on the vehicle body is performed according to the target complex permittivity and the solid electromagnetic simulation model of the first structure;

[0071] When an alternating current interference source with a frequency higher than a preset value is introduced, interference response analysis on the vehicle body is performed according to the target complex permittivity and the solid electromagnetic simulation model of the second structure;

[0072] The vehicle body structure included in the first structure is more complex than the vehicle body structure included in the second structure.

[0073] Specifically, the interference source usually includes a direct current interference source and an alternating current interference source. For the direct current interference source or the alternating current interference source with a frequency lower than a preset value, the frequency is relatively low, the simulation analysis is relatively easy, the calculation amount of the simulation analysis is relatively small, and the simulation analysis time required is relatively short. In order to improve the accuracy of the interference response analysis, in this case, the first structure corresponding to the solid electromagnetic simulation model can be relatively fine, such as considering some detailed lap joint structures and the like, that is, the solid electromagnetic simulation model has more detailed parts, so as to improve the accuracy of the interference response analysis.

[0074] For the alternating current interference source with a high frequency, the frequency is relatively high, the calculation amount required in the simulation analysis is relatively large, the simulation speed is relatively slow, and the simulation time required is relatively long. In this case, in order to improve the simulation speed and save the calculation resource, the vehicle body structure in the electromagnetic simulation model can be appropriately simplified (this part uses a simplified electromagnetic simulation model), such as some detailed lap joint structures or metal structures.

[0075] As a preferred embodiment, the composite structure is directly or indirectly connected with the grounding net through rivets or metal parts. In the simulation, the measured complex permittivity of the structure model is given to make the structure model a physical model with electrical connection properties, and then the electromagnetic simulation model of the first structure or the second structure is constructed.

[0076] Specifically, since the composite structure cannot be used as the equipotential reference surface of the vehicle body, the grounding net needs to be arranged separately. Therefore, as shown in Figure 2 , the composite vehicle body needs to be directly or indirectly connected with the grounding net through rivets or metal parts. In addition, the metal structure in the vehicle, such as a metal handrail, is also electrically connected to the vehicle body or the grounding net through the above connection mode. In this way, the composite vehicle body-grounding net-metal structure forms a composite vehicle body with complete grounding function.

[0077] As a preferred embodiment, the measurement method of the complex permittivity is as follows:

[0078] The three-electrode non-contact method is used to establish the corresponding equivalent circuit with the measured composite material as the measurement electrode.

[0079] The complex permittivity of the measured composite material is calculated according to the equivalent circuit.

[0080] Specifically, please refer to Figure 3 , Figure 3 The electrode sample arrangement diagram for measuring the complex permittivity is provided in the application. The impedance analyzer and the diameter test electrode are used to measure the anisotropic complex permittivity of the composite structure according to the three-electrode non-contact method. The guard electrode and the high-voltage electrode are the same as in the prior art, the measured composite material is arranged at the measurement electrode, and a certain gap is left between the measurement electrode and the guard electrode. The gap can be less than 0.2 mm.

[0081] As a preferred embodiment, the structure of the composite material to be measured includes a circular ring component and a cylindrical component, the circular ring component is sleeved outside the cylindrical component, and a gap is arranged between the circular ring component and the cylindrical component, and a gap is arranged between the outer layer of the circular ring component and the guard electrode.

[0082] Specifically, there is a small gap between the measurement electrode and the guard electrode, and because the conductivity of the composite material ranges from 100 S / m to 103 S / m, the conduction current on the contact surface between the measurement electrode and the sample may cross the gap to the non-measurement area (i.e., to the guard electrode), causing measurement errors.

[0083] Specifically, reference can be made to Figure 4a , Figure 4b and Figure 4c , wherein Figure 4a is a schematic diagram of the sample conduction current distribution of the composite material to be measured provided by the present application, Figure 4b is a schematic diagram of the sample conduction current distribution of the composite material to be measured provided by the present application, Figure 4c is a schematic diagram of the sample displacement current distribution of the composite material to be measured provided by the present application. The complex permittivity in the (x, y, z) direction is set to (10, 10, 1000), and the conduction current crossing phenomenon exists between the measurement electrode and the guard electrode of the complete sample. However, if the sample is removed from the part of the sample corresponding to the gap at the gap, the conduction current crossing phenomenon can be suppressed. Opening the gap may introduce stray capacitance, but through the displacement current distribution at the gap, no local enhancement phenomenon is found, and the edge capacitance effect of the small gap is not obvious. The above-mentioned sample is the composite material to be measured.

[0084] Therefore, the structure of the composite material to be measured in the embodiment is limited, which can be specifically set as a composite material to be measured including a circular ring component and a cylindrical component, wherein the circular ring component is sleeved outside the cylindrical component, and a gap (which is the gap described above) is arranged between the circular ring component and the cylindrical component, and a gap (which is the gap between the guard electrode and the test electrode described above) is arranged between the outer layer of the circular ring component and the guard electrode.

[0085] In addition, in order to further measure the anisotropy of the composite material to be measured, the composite material to be measured in the present application can include sample 1 and sample 2, wherein sample 1: the lamination plane is perpendicular to the axis, sample 2: the lamination plane is parallel to the axis, the thickness is 2mm-10mm, and the lamination can be fabric or unidirectional tape. That is, the combination of the cylindrical component and the circular ring component can be placed vertically or horizontally.

[0086] It can be seen that through the structure in the embodiment, the phenomenon of conduction current crossing from the measurement electrode to the guard electrode can be suppressed, measurement errors can be avoided, and the accuracy of measurement can be improved.

[0087] As a preferred embodiment, the complex permittivity of the measured composite material is calculated according to the equivalent circuit, comprising:

[0088] A plurality of equivalent equations are constructed according to the air equivalent circuit when the measured composite material is not loaded, the gap equivalent circuit when the measured composite material is loaded, and the equivalent circuit of the gap and the measured composite material when the measured composite material is loaded.

[0089] The inductance, capacitance and resistance of the measured composite material are calculated according to the plurality of equivalent equations.

[0090] The complex permittivity of the measured composite material is calculated according to the inductance, capacitance and resistance of the measured composite material.

[0091] As a preferred embodiment, the equivalent equation comprises:

[0092] The first equivalent equation:

[0093] The second equivalent equation:

[0094] The third equivalent equation:

[0095] The fourth equivalent equation:

[0096] Y0=1 / (jωC0) g Y0=1 / (jωC0) tg Y0=1 / (jωC0)

[0097] Specifically, the embodiment aims to provide a specific way of measuring the complex permittivity by the three-electrode method. Referring to Figure 5a 、 Figure 5b and Figure 5c wherein, Figure 5a is the equivalent circuit diagram provided by the present application when the measured composite material is not loaded, Figure 5b is the first equivalent circuit diagram provided by the present application after the measured composite material is loaded, Figure 5c is the second equivalent circuit diagram provided by the present application after the measured composite material is loaded. According to the above three equivalent circuit diagrams, the four equivalent equations (1)-(4) described above can be obtained. Subtracting equation (1) from equation (3) to obtain equation (5):

[0098]

[0099] The parameters on the right side of equation (5) are all measurable parameters. Substituting them into equation (4), we get:

[0100]

[0101] Equation (6) has three unknown parameters on the left: L1, C1, and R1. Y1 is measurable. Assuming the equation is linear within a certain frequency range, and L1, C1, and R1 remain unchanged, the number of equations obtained by measuring Y1 at multiple frequency points is much greater than the number of unknowns, forming an overdetermined system of equations. Therefore, the least squares method in the complex domain is used to estimate the circuit model parameters to obtain the circuit model parameter estimation equations to solve for L1, C1, and R1, as shown in equation (7):

[0102] A×K=B

[0103]

[0104] Equation (7) can be simplified to matrix form AK = B. Matrix A and B are obtained through multi-point measurement data, and K can be solved to obtain C1, R1, and L1. Here, with the target frequency point as the center, multiple frequency points are measured within a frequency band of 10%-30% of the center frequency to solve the least squares estimation equation (7).

[0105] The following is a method for obtaining the complex permittivity ε = ε' - ε" by measuring C1, R1, and L1: (e.g.) Figure 6a and 6b As shown, Figure 6a This application provides a schematic diagram of a measurement structure. Figure 6b An equivalent circuit diagram is provided for this application. The test sample (MUT) is equivalent to a parallel LCR equivalent circuit model, where R1 is the equivalent resistance caused by relaxation loss due to material polarization, C1 is the capacitance caused by sample polarization effect, L1 is the inductance caused by conduction current, and R2 is the high-frequency AC resistance of the sample.

[0106] Based on the equivalent circuit of the sample, we obtain:

[0107]

[0108] Taking R2, R1, and C1 as an equivalent capacitor, the current flowing through it and the approximate internal field are as follows:

[0109]

[0110]

[0111] Where I' is the sum of the capacitor polarization and conduction currents, E is the electric field strength inside the equivalent capacitor, J is the current density inside the equivalent capacitor, A is the electrode area, and tm is the sample thickness.

[0112] According to the intrinsic relation of the material:

[0113]

[0114] Where σ: sample conductivity, which can be obtained according to R2, Admittance.

[0115] Substitute current I', voltage V and ε = ε' - ε" into the above formula (11), we get:

[0116]

[0117] Comparing formula (12) with formula (9), we get:

[0118]

[0119] As shown in Figure 4, the precise impedance analyzer built-in LCR three-element parallel equivalent circuit model, circuit parameters R0, C0 and L1 can be directly read out.

[0120] Please refer to Figure 7 , Figure 7 The impedance analyzer LCR three-element parallel equivalent circuit model provided in this application is shown in the figure.

[0121] According to formula (8), we get Figure 2 The sample circuit parameters in Figure 7 The instrument circuit parameters match to get formula (14):

[0122] R0 = R1 + R2, C0 = C1, L0 = L1 (14)

[0123] Assuming R2 remains unchanged at low frequency, equal to the direct current resistance, then, formula (13) can be obtained:

[0124]

[0125] According to the above formula, the real part and the imaginary part of the sample complex dielectric constant can be calculated.

[0126] It should be noted that when calculating the imaginary part of the complex dielectric constant, the high-frequency alternating current resistance is equal to the direct current resistance, but the skin effect will cause the current lines to be concentrated towards the edge of the sample as the frequency increases, thereby causing the alternating current resistance to deviate from the direct current resistance value, and the greater the conductivity, the more obvious the skin depth. Therefore, a reasonable measurement frequency range needs to be determined. Due to the anisotropy of the composite material, the conductivity of the cross-section direction of the composite material is much larger than that of the thickness direction, about 1450 S / m. Under the premise of determining the size of the electrode, the conductivity of the cross-section direction determines the upper limit of the test frequency: assuming that the skin depth needs to be greater than the diameter of the electrode 5 mm, then the calculated frequency range is less than 6.99 MHz, at this time, the alternating current resistance deviates from the direct current resistance within 5%, and the alternating current resistance can be considered to be approximately equal to the direct current resistance. The imaginary part of the complex dielectric constant represents the relaxation loss, which is much smaller than the inherent conductivity loss of the composite material, and the influence of the imaginary part can be ignored. For example, when measuring the complex dielectric constant is only used for high-frequency simulation, the influence of the frequency limit on the imaginary part can be ignored.

[0127]

[0128] In summary, the calculation method in the present application can measure the complex dielectric constant at different frequencies to obtain the frequency-constant correspondence.

[0129] In summary, the train interference analysis method in the present application can analyze the interference response of the train body including the composite material by establishing an electromagnetic simulation model including the composite structure, the metal structure and the lap joint structure. In addition, when analyzing the interference of the train body, the target complex dielectric constant corresponding to the current test frequency is used instead of using a fixed complex dielectric constant, which improves the accuracy of the interference response analysis of the train body.

[0130] Please refer to Figure 8 , Figure 8 The structure block diagram of a train interference analysis device provided by the present application is shown in the figure, and the device comprises:

[0131] The memory 81 is used to store the computer program.

[0132] The processor 82 is used to realize the steps of the train interference analysis method as described above when storing the computer program. For the train interference analysis device, please refer to the above embodiments, which will not be described here again.

[0133] To solve the above technical problems, the present application also provides a computer readable storage medium, and the computer readable storage medium stores a computer program. When the computer program is executed by the processor, the steps of the train interference analysis method as described above are realized. For the computer readable storage medium, please refer to the above embodiments, which will not be described here again.

[0134] It should also be noted that, in the specification, relational terms such as first and second, and the like, can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0135] The above description of disclosed embodiments provides enabling concepts for practicing or using the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for analyzing interference in trains, characterized in that, include: The complex permittivity corresponding to the current frequency is measured in advance at different frequencies to obtain the correspondence between the complex permittivity and the frequency. The correspondence includes at least the nonlinear data of the complex permittivity changing with the frequency. A solid electromagnetic simulation model is established based on the train's body structure. The body structure includes at least a solid composite structure, a solid metal structure, and a solid overlapping structure for connecting the solid composite structure and the solid metal structure. Determine the target complex permittivity corresponding to the current simulation frequency based on the current simulation frequency and the corresponding relationship; A preset interference source is introduced, and the interference response of the vehicle body is analyzed based on the target complex permittivity and the physical electromagnetic simulation model. The method for measuring the complex permittivity is as follows: The equivalent circuit is established by using the composite material under test as the measuring electrode and employing the three-electrode non-contact method. The complex dielectric constant of the composite material under test is calculated based on the equivalent circuit. The complex dielectric constant of the composite material under test is calculated based on the equivalent circuit, including: Multiple equivalent equations are constructed based on the air equivalent circuit when the composite material under test is not loaded, the gap equivalent circuit when the composite material under test is loaded, and the gap and the equivalent circuit of the composite material under test when the composite material under test is loaded. The inductance, capacitance, and resistance of the composite material under test are calculated based on the multiple equivalent equations described above. The complex dielectric constant of the composite material under test is calculated based on its inductance, capacitance, and resistance.

2. The train interference analysis method as described in claim 1, characterized in that, The preset interference source includes a DC interference source, and / or an AC interference source with a frequency lower than the preset value, and / or an AC interference source with a frequency higher than the preset value.

3. The train interference analysis method as described in claim 1, characterized in that, The preset interference sources include stray current, and / or traction inverter interference signals, and / or lightning waveforms.

4. The train interference analysis method as described in claim 2, characterized in that, Introducing a preset interference source, and performing interference response analysis on the vehicle body based on the target complex permittivity and the physical electromagnetic simulation model, including: When the DC interference source or the AC interference source with a frequency lower than the preset value is introduced, the interference response analysis of the vehicle body is performed based on the target complex permittivity and the solid electromagnetic simulation model of the first structure. When an AC interference source with a frequency higher than the preset value is introduced, the vehicle body is subjected to interference response analysis based on the target complex permittivity and the physical electromagnetic simulation model of the second structure. The vehicle body structure included in the first structure is more complex than the vehicle body structure included in the second structure.

5. The train interference analysis method as described in claim 1, characterized in that, The solid composite structure is directly or indirectly connected to the grounding grid via rivets or metal components.

6. The train interference analysis method according to any one of claims 1-5, characterized in that, The structure of the composite material to be tested includes a ring component and a cylindrical component. The ring component is fitted over the outer layer of the cylindrical component, and there is a gap between the ring component and the cylindrical component. There is also a gap between the outer layer of the ring component and the protective electrode.

7. The train interference analysis method as described in claim 6, characterized in that, The equivalent equation includes: First equivalent equation: ; Second equivalent equation: ; Third equivalent equation: ; Fourth equivalent equation: ; in, This represents the air admittance without the composite material being tested being loaded. The admittance of the gap between the composite under test and the protective electrode after loading the composite under test. The capacitance of air of the same size as the composite material under test. The air resistance when the composite material under test is not loaded. Let Y be the air capacitance when the composite material under test is not loaded, and let Y be the admittance of the gap and the composite material under test after the composite material under test is loaded. Let Δ be the admittance of the composite material under test, and Δ be the error caused by edge and ground capacitance effects.

8. The train interference analysis method as described in claim 1, characterized in that, The complex permittivity at the current frequency is measured in advance at different frequencies, including: Determine the target frequency point for the train in practical applications; Using the target frequency as the center frequency, multiple frequency points are measured within a frequency band of 10%-30% of the center frequency to obtain the complex permittivity corresponding to each of the multiple frequency points.

9. A train interference analysis device, characterized in that, include: Memory, used to store computer programs; A processor, configured to implement the steps of the train interference analysis method as described in any one of claims 1-8 while storing a computer program.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the train interference analysis method as described in any one of claims 1-8.

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