New energy high-frequency wire harness design method based on electromagnetic compatibility optimization

Abstract

The application aims to provide a new energy high-frequency wire harness design method based on electromagnetic compatibility optimization, and relates to the technical field of new energy, which comprises the following steps: step 1: an electromagnetic source model of the new energy high-frequency wire harness is established to obtain electromagnetic source intensity; based on the electromagnetic source intensity, the spatial electromagnetic field intensity is calculated; step 2: based on the spatial electromagnetic field intensity, the equivalent transmission line parameters are calculated; based on the equivalent transmission line parameters, the frequency-varying characteristic impedance is calculated; step 3: according to the frequency-varying characteristic impedance, the crosstalk voltage is calculated; the radiation field of the new energy high-frequency wire harness is calculated; according to the radiation field, the shielding effectiveness of the new energy high-frequency wire harness is calculated; step 4: according to step 1, step 2 and step 3, the constraint condition is set, and the objective function under the constraint condition is established; the objective function is solved by iteration to find the optimal design parameter vector of the corresponding new energy high-frequency wire harness. The application significantly improves the transmission stability and anti-interference ability of the new energy high-frequency wire harness.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy, and particularly relates to a new energy high-frequency wire harness design method based on electromagnetic compatibility optimization. BACKGROUND

[0002] In the modern new energy application field, especially under the background of rapid development of new energy vehicles and high-frequency signal transmission systems, the electromagnetic compatibility (EMC) of new energy high-frequency wire harness is particularly important. During high-frequency signal transmission, electromagnetic interference can cause signal crosstalk, radiation interference and other problems, thereby affecting the transmission quality and reliability of the system. With the increasing number of high-frequency devices such as high-frequency current driving systems and communication modules in new energy vehicles, the electromagnetic interference problem in the wire harness system becomes increasingly complex. The prior art has proposed various design methods to deal with high-frequency electromagnetic interference, but there are still many technical difficulties and problems to be solved.

[0003] Firstly, the prior art usually uses shielding materials to control high-frequency electromagnetic interference, but the shielding effectiveness of shielding materials under high-frequency current is not stable. Typical electromagnetic shielding design uses metal materials to cover the wire harness, and realizes reflection and absorption of electromagnetic interference through the conductive properties of metal materials. However, the higher the frequency, the stronger the penetration of electromagnetic waves, and the effectiveness of traditional metal shielding layers gradually decreases under high-frequency conditions. Especially under the influence of skin effect, the current concentrates on the surface of the shielding material rather than flowing inside, which causes the thickness of the shielding layer to significantly increase the shielding effect under very high frequency. Due to this characteristic, how to design a shielding layer with high attenuation effect under the premise of ensuring high-frequency shielding effectiveness is still a difficulty in the prior art. In addition, the traditional shielding material design usually only considers electromagnetic interference in a single frequency band or a narrow frequency band, and cannot provide stable shielding effectiveness in a wider frequency range. Secondly, the prior art usually relies on reasonable wire harness arrangement and distance control to control crosstalk. The distance between adjacent wire harnesses is one of the key factors affecting crosstalk voltage, and by increasing the distance between wire harnesses, the electromagnetic coupling strength between them can be reduced to a certain extent. However, in new energy vehicles, the number of wire harnesses is large and the space is limited, and the distance control between wire harnesses is limited, which makes it impossible to effectively reduce crosstalk by increasing the distance in some designs. In addition, during high-frequency signal transmission, electromagnetic coupling is more serious than in low-frequency cases, and the rapidly changing components in the signal produce strong transient voltages in adjacent wire harnesses. This transient interference not only affects the quality of signal transmission, but also reduces the stability of the entire system. Although the prior art has tried to use multi-layer shielding design to enhance the anti-crosstalk ability, such a solution increases the complexity and cost of the system, and has limited effect outside a certain frequency range. SUMMARY

[0004] Therefore, the main purpose of the present application is to provide a new energy high-frequency wire harness design method based on electromagnetic compatibility optimization, which realizes accurate control of electromagnetic interference of new energy high-frequency wire harness in complex electromagnetic environment. The method makes the new energy high-frequency wire harness maintain low radiation, low crosstalk and high shielding effectiveness under high frequency conditions through global optimization of the objective function, significantly improving the transmission stability and anti-interference ability of the new energy high-frequency wire harness.

[0005] In order to achieve the above purpose, the technical scheme of the present application is as follows:

[0006] The new energy high-frequency wire harness design method based on electromagnetic compatibility optimization comprises the following steps:

[0007] Step 1: Establishing a formula electromagnetic source model of the new energy high-frequency wire harness to obtain the electromagnetic source intensity of the new energy high-frequency wire harness at each spatial point; based on the electromagnetic source intensity, calculating the spatial electromagnetic field intensity;

[0008] Step 2: Based on the spatial electromagnetic field intensity, calculating the equivalent transmission line parameters of the new energy high-frequency wire harness; based on the equivalent transmission line parameters, calculating the frequency-dependent characteristic impedance of the new energy high-frequency wire harness;

[0009] Step 3: According to the frequency-dependent characteristic impedance, analyzing the crosstalk between adjacent wire harnesses in the new energy high-frequency wire harness, calculating the crosstalk voltage; according to the crosstalk voltage, calculating the radiation field of the new energy high-frequency wire harness; according to the radiation field, calculating the shielding effectiveness of the new energy high-frequency wire harness;

[0010] Step 4: According to step 1, step 2 and step 3, setting the constraint condition and establishing the objective function under the constraint condition, and solving the objective function by iteration to find the optimal design parameter vector of the new energy high-frequency wire harness; designing the new energy high-frequency wire harness through the optimal design parameter vector; the elements of the optimal design parameter vector include: the number of current sources of the new energy high-frequency wire harness, frequency-dependent resistance, frequency-dependent inductance, frequency-dependent capacitance, frequency-dependent conductance, shielding layer thickness and wire harness current.

[0011] Further, in step 1, the formula electromagnetic source model of the new energy high-frequency wire harness is established by the following formula to obtain the electromagnetic source intensity of the new energy high-frequency wire harness at each spatial point:

[0012]

[0013] Wherein, S(r,ω) represents the electromagnetic source intensity at the spatial point r under a given frequency ω; N is the number of current sources of the new energy high-frequency wire harness; i is an integer index; I i is the current intensity of the i th current source; is the attenuation factor of the current source intensity in the spatial propagation process, which simulates the inverse square attenuation characteristic of the distance from the current source to the spatial point; ri is the position vector of the i-th current source; t is the time variable; j is the negative imaginary unit; denotes the curl operation on the magnetization M i (r) of the i-th current source; M i (r) is the magnetization at the i-th current source, is the curl operator, which denotes the magnetization effect of the magnetic field generated by the current source on the surrounding region.

[0014] Further, in step 1, the spatial electromagnetic field intensity is calculated based on the electromagnetic source intensity by the following formula:

[0015]

[0016] where E(r, ω) denotes the spatial electromagnetic field intensity at spatial point r under given frequency ω; the skin depth δ(ω) defines the penetration depth of the electric field in the medium under frequency ω; r' is the position integral variable;

[0017] G(r, r') is the corresponding propagation Green's function under the position integral variable; S(r', ω) is the corresponding form of S(r, ω) under the position integral variable; V is the spatial range of the new energy high-frequency wire bundle.

[0018] Further, in step 2, the equivalent transmission line parameters of the new energy high-frequency wire bundle are calculated based on the spatial electromagnetic field intensity by the following formula:

[0019]

[0020] where, is the equivalent transmission line parameter of the new energy high-frequency wire bundle; R(ω) is the frequency-dependent resistance under given frequency ω; |E(r, ω)| is the modulus of the electric field intensity; σ c is the conductivity of the conductor of the new energy high-frequency wire bundle; C denotes the surrounding closed path of the new energy high-frequency wire bundle; dl denotes the distance integral variable on the surrounding closed path of the new energy high-frequency wire bundle; L(ω) is the frequency-dependent inductance under given frequency ω; μ0 is the vacuum permeability; d max is the diameter of the outer conductor of the new energy high-frequency wire bundle; d min is the diameter of the inner conductor of the new energy high-frequency wire bundle; μ r is the relative permeability of the new energy high-frequency wire bundle, which indicates the magnetic conductivity of the material of the new energy high-frequency wire bundle relative to the vacuum; ε r is the relative permittivity of the new energy high-frequency wire bundle, which indicates the capacitive characteristics of the material of the new energy high-frequency wire bundle relative to the vacuum; ε0 is the vacuum permittivity; C(ω) is the frequency-dependent capacitance under given frequency ω; G(ω) is the frequency-dependent conductance under given frequency ω; σ d is the conductivity of the medium.

[0021] Furthermore, in step 2, the frequency-varying characteristic impedance of the new energy high-frequency harness is calculated based on the equivalent transmission line parameters using the following formula:

[0022]

[0023] Among them, Z c γ(ω) is the frequency-varying characteristic impedance at a given frequency ω; γ(ω) is the propagation constant at a given frequency ω. X represents the length of the high-frequency wiring harness for new energy applications.

[0024] Furthermore, in step 3, the crosstalk between adjacent wires in the new energy high-frequency wire harness is analyzed and the crosstalk voltage is calculated based on the frequency-varying characteristic impedance using the following formula:

[0025]

[0026] Where Z0 is the nominal characteristic impedance; M 12 (ω) is the mutual inductance coefficient, representing the degree of electromagnetic coupling between two wire bundles; it is the mutual inductance of adjacent wire bundles at frequency ω; V xt (r,ω) represents the crosstalk voltage at a spatial point r at a given frequency ω.

[0027] Furthermore, in step 3, the radiation field of the new energy high-frequency harness is calculated based on the crosstalk voltage using the following formula:

[0028]

[0029] Among them, E rad (r,ω) represents the radiation field at a given frequency ω at a spatial point r after the addition of a shielding layer; k is the wave number; k is the wave vector.

[0030] Furthermore, in step 3, the shielding effectiveness of the new energy high-frequency wire harness is calculated based on the radiation field using the following formula:

[0031]

[0032] Where D is the shielding layer thickness of the new energy high-frequency harness; SE(ω) is the shielding effectiveness at frequency ω, in decibels; E0(r,ω) is the radiation field at spatial point r at frequency ω without shielding; α(ω) represents the attenuation constant at frequency ω, which determines the absorption intensity of electromagnetic waves by the shielding layer, and is a set value.

[0033] Furthermore, in step 4, constraints are set using the following formula:

[0034] |E rad (r,ω)| <E lim ;

[0035] |V xt (z,ω)|<V lim ;

[0036] SE(ω)>SE min ;

[0037] |Z c (ω)-Z0|<ΔZ max ;

[0038] wherein, E lim is a set radiation limit; V lim is a set crosstalk limit; SE ref is a target shielding effectiveness; ΔZ max is a set characteristic impedance threshold; and the objective function is defined as:

[0039]

[0040] min{EMC total};

[0041] wherein, EMC total is a performance indicator; ω1 is a set lower frequency limit; and ω2 is a set upper frequency limit.

[0042] With the above technical solution, the application has the following intended effects: The application accurately calculates the electromagnetic source intensity of each spatial point through the distributed electromagnetic source model, thereby realizing comprehensive analysis of electromagnetic field distribution in the high-frequency wire harness system. Traditional wire harness electromagnetic interference calculation methods usually ignore the distribution characteristics of current sources in space, while the application adds distribution calculation of electromagnetic source intensity in the modeling of high-frequency signals. Such distributed modeling method can effectively capture the electromagnetic field change of high-frequency electromagnetic signals at different spatial points. On this basis, through further field intensity calculation and equivalent transmission line parameter extraction, the application realizes accurate description of electromagnetic field intensity under different frequency conditions, thereby providing more accurate electromagnetic interference evaluation data. This fine electromagnetic source modeling method improves the accuracy of electromagnetic compatibility design, enabling designers to more accurately control and optimize electromagnetic interference characteristics in practical applications. Secondly, the application accurately evaluates the propagation characteristics of electromagnetic interference by calculating frequency-dependent characteristic impedance, crosstalk voltage and radiation field, and effectively controls signal attenuation and interference under high-frequency conditions. The calculation of frequency-dependent characteristic impedance can track the impedance changes of the wire harness in real time at different frequencies, thereby enabling the transmission impedance of the high-frequency wire harness system to remain stable within a wide frequency band. Impedance matching is crucial for reducing signal reflection and transmission loss, and the application effectively reduces the reflection loss of high-frequency signals in transmission and improves transmission efficiency through dynamic impedance calculation and optimization. This impedance optimization strategy can significantly reduce signal power loss in practical applications, ensuring that the system maintains high transmission quality and stability in complex frequency environments. In terms of crosstalk suppression, the application introduces crosstalk voltage calculation, and through comprehensive analysis of factors such as frequency-dependent characteristic impedance, mutual inductance coefficient and current change rate, effective control of crosstalk between adjacent wire harnesses is realized. Traditional crosstalk control methods mostly rely on increasing the distance between wire harnesses or using multiple layers of shielding. The application combines current source changes, wire harness characteristics and electromagnetic coupling strength for comprehensive evaluation through accurate crosstalk voltage calculation, thereby achieving more efficient anti-crosstalk capability without significantly increasing system complexity. Especially under high-frequency conditions, due to the enhanced electromagnetic coupling strength, the method of the application can effectively reduce electromagnetic interference between adjacent wire harnesses, thereby improving the anti-interference performance of signals. BRIEF DESCRIPTION OF DRAWINGS

[0043] Other features, objects, and advantages of the application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings:

[0044] Figure 1 The method flowchart of the new energy high-frequency wire harness design method based on electromagnetic compatibility optimization provided by the embodiment of the application. DETAILED DESCRIPTION

[0045] The method of the present application will be further described in detail below in combination with the accompanying drawings and embodiments of the present application.

[0046] Embodiment 1: Reference Figure 1 A new energy high-frequency wire harness design method based on electromagnetic compatibility optimization, the method comprising:

[0047] Step 1: Establish a distributed electromagnetic source model of the new energy high-frequency wire harness to obtain the electromagnetic source intensity of the new energy high-frequency wire harness at each spatial point; based on the electromagnetic source intensity, calculate the spatial electromagnetic field intensity;

[0048] Since new energy equipment often operates under high frequency conditions, it causes strong electromagnetic interference in the internal wire harness system, and these interferences become more complex and difficult to control as the frequency increases. The electromagnetic source distribution of the high-frequency wire harness has significant spatial and frequency dependence, therefore, designing an electromagnetic source model that can accurately reflect the electromagnetic field distribution characteristics becomes the basis for optimization design. The present application considers the spatial position, frequency characteristics and mutual coupling relationship of each current source in the high-frequency wire harness by establishing a distributed electromagnetic source model, thereby accurately expressing the electromagnetic source intensity at each position. The construction process of the electromagnetic source model is based on the mathematical expression of each current source, so that the contribution of the current source to the electromagnetic field in space can be described by parameters such as source position, frequency, amplitude and phase. In the actual high-frequency wire harness, different current sources are located at different spatial positions, and these current sources not only excite at a specific frequency, but also interfere with each other due to factors such as spatial distance, conductor medium, etc. Therefore, in order to accurately describe the electromagnetic source intensity of the current source in space, the model of the present application introduces the spatial distance factor between the source and the field, so that the electromagnetic field contribution of each current source gradually decays as the distance between the source point and the field point increases, which conforms to the inverse square law of electromagnetic radiation. At the same time, by combining the frequency components of each current source, the model can accurately reflect the dynamic changes caused by high-frequency current sources. This dynamic change includes the phase change over time, and the phase at different frequencies is described by a complex phase term, so as to reflect the fluctuation characteristics of the high-frequency current source in the time domain in the model.

[0049] In this electromagnetic source model, the spatial distribution and mutual coupling of multiple current sources are described through the superposition principle, which enables the model to capture the complex field effects of current sources in high-frequency wire bundles. Specifically, the electromagnetic source model treats each current source as an independent point source and calculates the electromagnetic field contribution of each source to any point in space through superposition. The electromagnetic contribution of each source is determined by its own intensity and spatial position, while its phase term determines the time-domain variation pattern of the electromagnetic field, which reflects the periodicity and frequency dependence of high-frequency signals. Through the distributed superposition method, the model can handle the resonance effects of multiple current sources at the same frequency and the mutual interference at different frequencies, thus forming a complete spatial electromagnetic field distribution. The model not only describes each current source independently, but also includes the coupling characteristics between different sources. Coupling effects are an important factor that cannot be ignored between high-frequency current sources, especially in high-density wire bundles, where strong electromagnetic coupling may occur between adjacent current sources, leading to amplification of interference signals. By introducing the interaction term between current sources in the model, the interference strength and interference pattern between multiple current sources can be more accurately reflected. This coupling description takes into account the phase synchronization phenomenon of current sources at the same frequency and the interference effect between different frequencies, enabling the electromagnetic source model to be used for complex electromagnetic interference analysis under high-frequency conditions. Specifically, this interaction term is calculated through the distance between the source and the field point and the propagation path of the electromagnetic wave, ensuring that the model can exhibit consistent coupling relationships at different frequencies and different positions.

[0050] In addition, the electromagnetic source model also introduces a frequency-dependent spatial attenuation factor to describe the penetration and attenuation of electromagnetic fields in transmission media. One of the characteristics of high-frequency electromagnetic wave propagation in media is the skin effect, that is, the field strength of electromagnetic waves gradually decreases with distance, especially in media with high conductivity, the field strength attenuation is more obvious. By incorporating the skin effect into the electromagnetic source model, the attenuation characteristics of high-frequency current sources in different media can be accurately simulated. This attenuation factor not only depends on the spatial distance, but also depends on the frequency, so that the model can reflect the attenuation law at different frequencies, especially in the high-frequency state, it can show strong field strength attenuation phenomenon, so as to be more consistent with the actual physical situation. The output result of the electromagnetic source model is the electromagnetic source intensity data at each spatial point, which provides the basic input condition for the subsequent calculation of electromagnetic field strength. Electromagnetic source intensity is the initial distribution of electric field and magnetic field in space, and in the design of new energy high-frequency wire harness, these data are directly related to the calculation of transmission line characteristics, impedance matching analysis and shielding effect evaluation. Since the model can accurately reflect the electromagnetic contribution of each current source at different positions in space, it provides a systematic method to analyze the overall electromagnetic characteristics of the wire harness system. As the number of current sources and frequency increases, the complexity of the model will also increase accordingly, but the calculation accuracy and spatial accuracy of electromagnetic field distribution will also be improved simultaneously. This method can ensure that the calculation results of electromagnetic source intensity are more consistent with the actual electromagnetic field distribution, especially in complex structures and multi-source conditions, the resolution capability of the model is further improved.

[0051] Step 2: Based on the spatial electromagnetic field strength, calculate the equivalent transmission line parameters of the new energy high-frequency wire harness; based on the equivalent transmission line parameters, calculate the frequency-dependent characteristic impedance of the new energy high-frequency wire harness;

[0052] The electromagnetic source intensity distribution provides the initial electromagnetic field information of each point in space, which determines the electromagnetic interference behavior and transmission characteristics of the high-frequency wire harness under specific frequency and geometric conditions. The working frequency of the new energy high-frequency wire harness is high, and the structure is complex. The electromagnetic field distribution around it is often not uniform, but is affected by multiple factors such as current source position, electrical conductivity, and dielectric, showing spatial and frequency dependence. Therefore, the principle of this step is mainly to analyze the spatial electromagnetic field intensity to obtain accurate transmission line equivalent parameters, which will be used in further electromagnetic compatibility optimization. In this calculation process, first, according to the electromagnetic source intensity obtained from the distributed electromagnetic source model, the electric field and magnetic field intensity in space are calculated by spatial integration. The calculation of spatial integration not only considers the independent contribution of each current source in space, but also reflects the propagation path and attenuation characteristics of electromagnetic waves in different media. Since electromagnetic waves under high-frequency conditions often have strong attenuation and refraction effects, the skin effect is also considered in the model, i.e., the phenomenon that electromagnetic waves gradually weaken with increasing transmission distance. This effect is particularly significant in conductive materials, especially under high-frequency working conditions, where electromagnetic energy tends to concentrate on the surface of the material, while the interior shows a rapid decay trend. This physical property is introduced into the frequency-dependent attenuation factor in the calculation of electromagnetic field intensity, which accurately reflects the field strength changes of electric and magnetic fields at different positions in the medium, providing a real data basis for the extraction of transmission line parameters. After obtaining the spatial electromagnetic field distribution information, the equivalent transmission line parameters of the new energy high-frequency wire harness are further calculated. The equivalent parameters of the transmission line include frequency-dependent resistance, inductance, capacitance, and conductance, which describe the propagation characteristics of electromagnetic signals in the high-frequency wire harness and are the key data for electromagnetic compatibility optimization. Specifically, the frequency-dependent resistance represents the current loss in the conductor, the frequency-dependent inductance describes the magnetic field effect caused by current changes, the frequency-dependent capacitance reflects the electric field coupling effect between adjacent conductors, and the frequency-dependent conductance describes the leakage behavior in the medium. Each parameter involves different electromagnetic phenomena, and the combined effect of these phenomena determines the impedance characteristics of the transmission line at different frequencies. To accurately calculate these equivalent parameters, this step extracts the RLCG parameters of the transmission line by analyzing the electric and magnetic fields based on the spatial electromagnetic field distribution characteristics. Unlike the relatively simple impedance expression under low-frequency conditions, under high-frequency conditions, the RLCG parameters all change with frequency. Therefore, the frequency is introduced as a variable into the expression of the transmission line parameters in the calculation process, so that each parameter can change with frequency. Such frequency dependence not only enhances the adaptability of the model, but also better fits the physical characteristics of the high-frequency wire harness. Next, by combining the frequency-dependent resistance, inductance, capacitance, and conductance parameters, the frequency-dependent characteristic impedance of the transmission line is further calculated. The characteristic impedance is an important characteristic of the transmission line, which describes the response of the transmission line to electromagnetic signals at different frequencies.Characteristic impedance is crucial in electromagnetic compatibility design, as it affects the reflection and absorption of signals in transmission lines. By substituting the frequency-dependent RLCG parameters into the calculation formula of characteristic impedance, the impedance characteristic curve of new energy high-frequency wire harness at different frequencies is obtained. This curve describes the propagation mode of signals, and if the characteristic impedance of the transmission line does not match the load impedance, reflected signals will be generated, leading to electromagnetic compatibility problems of the system. By ensuring that the characteristic impedance of the transmission line matches the load impedance as much as possible in the design, the reflected signals can be reduced, and the transmission efficiency and electromagnetic compatibility of the system can be improved.

[0053] Step 3: According to the frequency-dependent characteristic impedance, analyze the crosstalk between adjacent wire harnesses in the new energy high-frequency wire harness, calculate the crosstalk voltage; according to the crosstalk voltage, calculate the radiation field of the new energy high-frequency wire harness; according to the radiation field, calculate the shielding effectiveness of the new energy high-frequency wire harness;

[0054] Firstly, the coupling strength between the wire bundles can be solved by characteristic impedance. Characteristic impedance describes the impedance characteristics of transmission lines at different frequencies, and in adjacent wire bundles, due to the impedance matching or mismatching of different transmission lines, different degrees of coupling will occur between adjacent wire bundles when signals are transmitted. This coupling is reflected in the mutual influence of electric field and magnetic field in space, and further leads to electromagnetic induction between adjacent conductors, which is called crosstalk. Crosstalk voltage is an important parameter to measure the coupling strength, which directly reflects the interference strength of the signal on one wire bundle to the adjacent wire bundle. The size of the crosstalk voltage depends on the current of the source wire bundle, the distance between them, the characteristic impedance of the wire bundle, and the electromagnetic properties of the medium around the conductor. In this invention, by combining the distribution of each current source with the calculation results of the characteristic impedance, the coupling coefficient between each adjacent wire bundle is obtained, and the crosstalk voltage is calculated using the coupling coefficient. This step ensures that the coupling degree of high-frequency signals between wire bundles can be accurately described under high-frequency working conditions, providing basic data for the next step of radiation field analysis. After obtaining the crosstalk voltage, the radiation field characteristics of the system can be further derived. High-frequency currents propagate in the form of waves in the transmission line, and the existence of crosstalk causes part of the signal energy to be radiated from the wire bundle to the outside space in the form of electromagnetic waves. The strength of this radiation field determines the electromagnetic interference strength of the system, and also reflects the electromagnetic compatibility level of the system. The radiation field of the high-frequency wire bundle is determined by factors such as its physical structure, frequency and current source strength. Through the calculation of crosstalk voltage and characteristic impedance, the invention further analyzes the radiation field of the wire bundle and obtains the radiation electric field strength of the system at a specific location in space. The radiation field calculation considers the phase relationship between the source point and the field point, the attenuation characteristics of the propagation path, and the directivity characteristics of electromagnetic waves in space, so that the radiation distribution of the system under high-frequency conditions can be accurately predicted. This process ensures the accuracy of the radiation field strength data and lays a data foundation for subsequent shielding effectiveness calculation. Shielding effectiveness calculation is an important part of electromagnetic compatibility optimization for high-frequency wire bundle systems. Through the evaluation of shielding effectiveness, it can be judged whether the existing shielding design is sufficient to suppress the interference of the radiation field on the external environment. Shielding effectiveness is defined as the logarithmic ratio of the radiation field strength of the system with and without shielding, reflecting the attenuation effect of the shielding layer on electromagnetic waves. For high-frequency wire bundles, shielding effectiveness not only depends on the conductivity and magnetic permeability of the shielding material, but also depends on the thickness of the shielding layer, the frequency and the spatial position. In this invention, the calculation of shielding effectiveness is based on the radiation field data described above, and by comparing the radiation intensity with and without shielding, the value of shielding effectiveness is obtained. A frequency-dependent attenuation factor is introduced in the calculation process, which accurately describes the propagation characteristics of electromagnetic waves in the shielding layer and reflects the absorption ability of the shielding material at different frequencies. By adjusting the thickness and material properties of the shielding layer, the best shielding design can be found, thereby effectively suppressing high-frequency radiation.

[0055] Step 4: According to step 1, step 2 and step 3, set the constraint conditions, and establish the objective function under the constraint conditions, find the optimal design parameter vector of the new energy high-frequency wire harness through iterative solution of the objective function; through the optimal design parameter vector, the new energy high-frequency wire harness is designed; the elements of the optimal design parameter vector include: the number of current sources of the new energy high-frequency wire harness, frequency-variable resistance, frequency-variable inductance, frequency-variable capacitance, frequency-variable conductance, shielding layer thickness and wire harness current.

[0056] Firstly, the optimization process starts with the establishment of the objective function. The definition of the objective function is based on the overall performance of the high-frequency wire harness system in electromagnetic compatibility, aiming to minimize the radiation field intensity, crosstalk voltage and ensure that the shielding effectiveness meets certain standards. Since the interference effects of the high-frequency wire harness system are different at different frequency ranges, the objective function weights the effects of different frequencies, which can ensure that the electromagnetic compatibility indicators are prioritized in the main working frequency band of the system. After setting the objective function, further combined with the physical characteristics of the new energy high-frequency wire harness, several constraint conditions are proposed. These constraint conditions include the limit value of radiation intensity, the maximum allowable value of crosstalk voltage and the minimum standard of shielding effectiveness, etc. In addition, in order to ensure the stability of the wire harness system in practical application, the range limit of characteristic impedance is also taken as a constraint condition, which can ensure that the system will not cause reflection and power loss due to impedance mismatch in high-frequency state. By integrating these objectives and constraints, the optimization problem is transformed into a multi-objective constrained optimization problem. Next, the optimization solution process uses an iterative algorithm, which gradually adjusts the design parameter vector to approach the optimal solution. The design parameter vector includes the number of current sources, frequency-variable resistance, inductance, capacitance, conductance, shielding layer thickness and wire harness current, etc. These parameters determine the electromagnetic characteristics of the system, so in the iteration process, the values of different parameters directly affect the effect of electromagnetic compatibility optimization. At each iteration, the algorithm calculates the corresponding electromagnetic compatibility indicator value according to the current design parameter vector, evaluates whether it meets the constraint conditions, and brings the result into the objective function. If the objective function value is large, it means that the current design does not meet the best electromagnetic compatibility standard, and the algorithm will adjust the parameter vector to further reduce the objective function value; if the objective function value is close to the minimum value, and all constraint conditions are met, it means that the current design parameter combination has reached a relatively optimal electromagnetic compatibility level. Through this iterative adjustment, the optimal parameter combination is constantly searched, thereby realizing the optimization design of the high-frequency wire harness system.

[0057] The difficulty of this optimization process lies in the comprehensive balance of multiple objectives and multiple constraints, as different design parameters have multiple influences on electromagnetic compatibility indicators. For example, increasing the thickness of the shielding layer can effectively improve the shielding effectiveness, thereby reducing the radiation field intensity, but it may also increase the frequency-dependent resistance of the system, thereby affecting the transmission efficiency of the system. Similarly, adjusting the number of current sources or the current intensity of the wire harness may reduce the crosstalk effect, but it will also change the characteristic impedance of the system, causing the matching to deviate. Therefore, the optimization algorithm needs to dynamically balance the influences between design parameters during the iteration process to find the minimum value of the objective function under the premise of meeting all the constraints. Finally, the optimal design parameter vector obtained through multiple rounds of iteration represents the best electromagnetic compatibility solution for the new energy high-frequency wire harness under the current design requirements. This optimal parameter vector provides a more accurate design reference for the wire harness system, not only ensuring that its radiation interference to the outside world is minimized within the working frequency band, but also effectively suppressing the crosstalk within the wire harness system to ensure the stability of signal transmission. With the help of this optimization design result, engineers can design the actual wire harness system based on these parameters, thereby meeting the electromagnetic compatibility requirements of new energy equipment under high-frequency working conditions.

[0058] In step 1 of Example 2, the electromagnetic source model of the new energy high-frequency wire harness is established by the following formula, and the electromagnetic source intensity of the new energy high-frequency wire harness at each spatial point is obtained:

[0059]

[0060] where S(r, ω) represents the electromagnetic source intensity at spatial point r under a given frequency ω; N is the number of current sources of the new energy high-frequency wire harness; i is an integer index; I i is the current intensity of the i-th current source; is the attenuation factor of the current source intensity in spatial propagation, to simulate the inverse square attenuation characteristic of the distance from the current source to the spatial point; r i is the position vector of the i-th current source; t is the time variable; j is the negative sign; represents the curl operation item of the magnetization M i (r); M i (r) is the magnetization at the i-th current source, is the curl operator, representing the magnetization effect of the magnetic field generated by the current source on the surrounding area.

[0061] Specifically, in this model, S(r, ω) represents the electromagnetic source strength at a point r in space at frequency ω. This source strength is mainly determined by factors such as the strength, position, and magnetization of the current source. In the design of new energy high-frequency wire harness, this electromagnetic source model is particularly crucial because it can truly reflect the distribution of electromagnetic interference sources in the wire harness system under high-frequency conditions. By calculating the electromagnetic field strength contribution of each current source, the formula synthesizes the superposition effect of multi-source interference, so that the electromagnetic source strength at any point in space can be accurately calculated. The first term in the model, i.e. describes the electromagnetic contribution of the i-th current source to the point r in space. The strength of the current source is represented by the current I i , which indicates its contribution to the electromagnetic field under high-frequency signals, while is a distance attenuation factor that describes the inverse square distance decay characteristic of the electric field strength from the current source to the point r. This decay characteristic conforms to the law of electromagnetic radiation propagation in free space, ensuring the physical reasonableness of the model. The farther the distance, the smaller the influence of the current source on the point, which is consistent with the physical law of actual electromagnetic field distribution. In this term, exp(-jωt) is also included as a phase factor, which describes the time dependence and frequency characteristics of the electromagnetic wave. The current source in the high-frequency wire harness is usually in an alternating current state, so the phase term reflects the dynamic changes of the current source, thus more realistically simulating the time-varying characteristics of the electromagnetic source. In addition, the unit vector indicates the direction from the current source position to the point r in space. The unit vector ensures that the model can accurately reflect the directionality of electromagnetic field propagation in space, thus more comprehensively describing the distribution of electromagnetic field in different directions.

[0062] The second term in the formula represents the curl of the magnetization term. This part is used to describe the magnetization effect of the magnetic field generated by the current source in the surrounding area. High-frequency current sources not only form an electric field around them, but also cause magnetization effects in space through the changes in the magnetic field, especially in the presence of magnetically conductive media, which will lead to more complex electromagnetic interference distribution. The curl operator is used to calculate the spatial distribution of the magnetization and its contribution to the electromagnetic field, and through this operation, the changes in the magnetization in various directions can be captured. In this model, the magnetization M i(r) represents the magnetic field effect of the current source on the surrounding space, which reflects how the magnetic field generated by the high-frequency current source in its area affects the magnetism of the surrounding medium. This item is particularly important because under high-frequency conditions, the propagation of electromagnetic fields is not only affected by the strength of the electric field, but also by the changes in the magnetic field, which can cause magnetization effects in space. By adding this item to the model, the spatial impact of the electromagnetic source can be described in a wider range, thereby improving the accuracy of the calculation results. The output of the electromagnetic source model is the electromagnetic source strength S(r, ω) of the new energy high-frequency wire bundle at each spatial point, which provides the initial conditions for subsequent electromagnetic field strength calculations. Due to the complexity of electromagnetic interference under high-frequency conditions, this distributed electromagnetic source model can capture the field strength changes of each current source at different spatial positions and directions, making the entire electromagnetic compatibility analysis process more accurate. The multiple components in the model allow the electromagnetic source strength at each spatial point to be calculated independently, which is particularly important under multi-source conditions, because the electromagnetic field generated by each current source in space will be superimposed and interfered with other sources, so to obtain the overall electromagnetic field distribution, the combined effect of all current sources needs to be calculated.

[0063] In step 1 of embodiment 3, the spatial electromagnetic field strength is calculated based on the electromagnetic source strength by the following formula:

[0064]

[0065] where E(r, ω) represents the spatial electromagnetic field strength at spatial point r under a given frequency ω; the skin depth δ(ω) defines the penetration depth of the electric field in the medium at frequency ω; r' is the position integral variable;

[0066] G(r, r') is the corresponding propagation Green's function under the position integral variable; S(r', ω) is the corresponding form of S(r, ω) under the position integral variable; V is the spatial range of the new energy high-frequency wire bundle.

[0067] Specifically, in the formula, E(r, ω) represents the electric field strength at a spatial point r at a frequency ω, which is the cumulative result of the source strength calculated by the electromagnetic source model in space. This accumulation process is completed through triple integration, which gradually adds the influence of current sources on each point in space to reflect the electric field distribution of the wire harness system in the overall space. The integral variable r' represents the position of each source point in space, and r' is taken point by point in the integration process to calculate the electric field contribution of all current sources to the spatial point r. This integration method ensures that the electric field strength at any point in space can be accurately calculated, thereby achieving full-space coverage of high-frequency electromagnetic fields. The Green function G(r, r') is an indispensable key part of the formula, which describes the propagation characteristics of electromagnetic waves in space, especially the mutual influence of electric fields between different positions. In electromagnetic field theory, the Green function can be understood as a kind of propagation weight function, which reflects the reflection, refraction and attenuation of electromagnetic waves in the medium by weighting the propagation path between the current source and the spatial point. By introducing the Green function, the model not only describes the propagation of electromagnetic waves in free space, but also effectively adapts to the propagation in different media. The introduction of the Green function ensures that the calculation of electromagnetic field strength can adapt to various space propagation environments, and the change of electric field strength under different media and different propagation distances can be accurately calculated. This feature is particularly important in complex environments, as new energy high-frequency wire harness systems often transmit signals in multiple media, and the electromagnetic propagation characteristics of different media are different, which directly affects the distribution of electromagnetic fields.

[0068] Exponential decay factor introduced in the formula is a key term for describing the skin effect. The skin effect is a fundamental characteristic of high-frequency electromagnetic wave propagation in conductive media, which describes the concentrated distribution characteristics of electromagnetic waves on the surface of the medium, that is, the electromagnetic field is mainly concentrated on the surface of the conductor under high-frequency conditions, and quickly attenuates in the interior of the conductor with the increase of the distance. The skin depth δ(ω) describes the penetration depth of electromagnetic waves at different frequencies, and the smaller the value of δ(ω), the faster the attenuation of electromagnetic waves in the conductor. Through this term, the energy distribution of electromagnetic waves in different frequencies and different media can be characterized. For example, in a highly conductive medium, the energy of high-frequency electromagnetic waves will quickly concentrate on the surface, the penetration depth is small, and the attenuation is faster; while in a low-conductive medium, the electromagnetic wave penetrates deeper. Therefore, the introduction of the exponential attenuation factor not only reflects the skin effect of the electromagnetic wave, but also accurately describes the field strength attenuation in different frequencies and different media, so that the calculation result of the electric field is closer to the actual physical environment. In the process of triple integration calculation, the electromagnetic source intensity S(r', ω) is the initial excitation source in this formula, which describes the electric field contribution of each current source in the high-frequency linear beam system in space. The electromagnetic source intensity is obtained from the previous electromagnetic source model, and is accumulated point by point in the triple integration to transfer the comprehensive electric field effect of the current source to each position point in space. This process can be understood as the accumulation of the field strength distribution produced by each current source at different spatial positions, and the electric field contribution of all current sources to a specific position will be integrated together to obtain the actual electric field strength at that position. Since the current sources in the high-frequency linear beam usually have different distributions in space, the calculation of the electric field strength must consider the different positions and directions of each source point. Through this way of spatial integration, the electric field distribution can be simulated in all directions, ensuring that the electric field strength at any position point in space can be obtained through accurate calculation. The principle of this electromagnetic field strength calculation formula also involves the phase relationship and spatial attenuation characteristics of electromagnetic waves. Under high-frequency conditions, the phase change of electromagnetic waves has an important influence on the electric field distribution, and the distance from the source point to the field point and the characteristics of the propagation medium will cause the phase change of electromagnetic waves, thereby affecting the final intensity distribution of the electric field. One of the functions of the Green function is to consider this phase effect, which describes the phase change of electromagnetic waves at different positions through the distance dependence of the propagation path, so that the electric field distribution is more in line with the phase superposition law in actual high-frequency propagation. In addition, the introduction of the skin effect term not only reflects the attenuation characteristics, but also makes the change of the electric field strength at different positions present the real attenuation law. The setting of the skin depth can ensure that the calculated electric field strength does not exceed the limit of the actual physical environment, so that the result is more meaningful.

[0069] In step 2, based on the spatial electromagnetic field strength, the equivalent transmission line parameters of the new energy high-frequency linear beam are calculated by the following formula:

[0070]

[0071] wherein, R(ω) is the frequency-dependent resistance at a given frequency ω; |E(r,ω)| is the modulus of the electric field intensity; σ c σ is the conductivity of the conductor of the new energy high-frequency wire harness; C represents a closed path around the new energy high-frequency wire harness; dl represents a distance integral variable on the closed path around the new energy high-frequency wire harness; L(ω) is the frequency-dependent inductance at a given frequency ω; μ0 is the vacuum permeability; d max d is the diameter of the outer conductor of the new energy high-frequency wire harness; d min d is the diameter of the inner conductor of the new energy high-frequency wire harness; μ r μ is the relative permeability of the new energy high-frequency wire harness, indicating the magnetic conductivity of the material of the new energy high-frequency wire harness relative to the vacuum; ε r ε is the relative permittivity of the new energy high-frequency wire harness, indicating the capacitive characteristics of the material of the new energy high-frequency wire harness relative to the vacuum; ε0 is the vacuum permittivity; C(ω) is the frequency-dependent capacitance at a given frequency ω; G(ω) is the frequency-dependent conductance at a given frequency ω; σ d σ is the conductivity of the medium.

[0072] Specifically, the frequency-dependent resistance R(ω) represents the energy loss characteristics of the high-frequency wire harness conductor at a specific frequency. The calculation process of the resistance is based on the modulus |E(r,ω)| of the spatial electromagnetic field intensity and is obtained by integrating the closed path C. By accumulating the ratio of the square of the electric field intensity on the path around the conductor, the total value of the power loss on the entire path can be obtained. This process actually simulates the gradual energy loss of the conductor under high-frequency current excitation. The essence of the resistance is the consumption of energy, which will cause the current to gradually attenuate during transmission. Under high-frequency conditions, the electromagnetic wave will produce "skin effect", that is, the current concentrates in the surface area of the conductor and does not uniformly distribute inside the conductor. The skin effect increases the energy consumption of the high-frequency current on the surface of the conductor, so the high-frequency resistance is usually higher than the low-frequency resistance. The conductivity σ c in the formula is the key to the calculation of resistance, which reflects the ability of the conductor to react to the current. The lower the conductivity of the conductor, the greater the resistance, the more energy is consumed, and the more serious the attenuation of the signal during transmission. The calculation of the frequency-dependent resistance provides a basis for power loss control in electromagnetic compatibility design, so that the resistance characteristics can be optimized by controlling the conductivity of the material during design. Secondly, the frequency-dependent inductance L(ω) describes the magnetic field characteristics of the high-frequency wire harness under alternating current. The inductance parameter is determined by the geometric structure of the conductor and the magnetic permeability of the material. The vacuum permeability μ0 is a basic constant in the calculation of inductance, which is used to determine the distribution of the magnetic field around the conductor without the influence of external magnetic materials. The relative permeability μ ris the magnetic permeability of the conductor material, which determines the amplification of the magnetic field in the material relative to the vacuum. The logarithmic ratio of the outer diameter d max and the inner diameter d min reflects the influence of the geometry on the magnetic field. The magnetic field will periodically change under high-frequency current and form a stable magnetic induction effect around the conductor. This effect is essentially an inductive effect, and the resulting magnetic field will react on the current, thereby limiting the rate of change of the current. The calculation of the frequency-dependent inductance can accurately quantify the magnetic field effect of high-frequency signals, allowing designers to adjust the inductance value of the wire bundle according to the magnetic permeability and geometry. In electromagnetic compatibility design, the size of the inductance affects the total impedance and signal delay of the transmission line, and a suitable inductance value can effectively balance the magnetic field strength and current stability.

[0073] The third parameter is the frequency-dependent capacitance C(ω), which describes the electric field coupling characteristics between conductors. The calculation of capacitance involves the vacuum permittivity ε0and the relative permittivity ε r , which together determine the coupling strength of the electric field in space. The vacuum permittivity is a fundamental constant that indicates the capacitive characteristics of the electric field propagating in a vacuum, while the relative permittivity reflects the amplification or weakening effect of the medium around the conductor on the electric field. Under high-frequency conditions, electromagnetic waves will form a strong electric field around the conductor, and the coupling characteristics between conductors due to the mutual attraction or repulsion of charges will exhibit a capacitive effect. The logarithmic ratio of the outer diameter and the inner diameter of the conductor reflects the coupling situation at different spatial distances. As the distance between conductors increases, the capacitance will decrease, which is consistent with the physical law that high-frequency electromagnetic waves gradually attenuate in space. The greater the capacitance, the stronger the coupling between conductors, which manifests as a more concentrated electric field between conductors. This electric field concentration effect will affect the propagation speed of high-frequency signals, thereby affecting the transmission performance in electromagnetic compatibility design. The calculation of the frequency-dependent capacitance provides a basis for optimizing the electric field distribution of the transmission line, allowing designers to control the permittivity and geometric parameters to adjust the capacitive characteristics. Finally, the frequency-dependent conductance G(ω) describes the leakage characteristics of the medium around the conductor. The conductivity σ dis an important parameter in the calculation of frequency-dependent conductance, which reflects the leakage of the medium under high-frequency signals. The calculation of the conductance parameter involves the geometric characteristics of the conductor, and the logarithmic ratio of the outer diameter to the inner diameter of the conductor reflects the influence of geometric parameters on leakage. Frequency-dependent conductance is of great significance in electromagnetic compatibility design, as it describes the penetration and leakage of electromagnetic signals in the medium. In high-frequency signal propagation, the electric field will form leakage around the conductor, causing the signal to gradually attenuate during transmission. The size of the frequency-dependent conductance directly determines the energy loss of the signal. By calculating the ratio of the outer diameter to the inner diameter of the conductor, the influencing factors of the frequency-dependent conductance can be obtained, thereby guiding the material selection and geometric design during design. Higher leakage will cause high-frequency signals to attenuate rapidly, which has an adverse effect on the transmission performance of high-frequency electromagnetic signals. The calculation of frequency-dependent conductance enables accurate control of the leakage amount in the medium in electromagnetic compatibility design, reducing the loss of high-frequency signals during transmission.

[0074] In step 2, the frequency-dependent characteristic impedance of the new energy high-frequency wire harness is calculated based on the equivalent transmission line parameters by the following formula:

[0075]

[0076] where Z c (ω) is the frequency-dependent characteristic impedance at a given frequency ω; γ(ω) is the propagation constant at a given frequency ω; X is the length of the new energy high-frequency wire harness.

[0077] Specifically, the calculation formula of the characteristic impedance includes the equivalent transmission line parameters of the transmission line, including the frequency-dependent resistance R(ω), the frequency-dependent inductance L(ω), the frequency-dependent capacitance C(ω), and the frequency-dependent conductance G(ω). These parameters describe the attenuation, coupling, energy storage, and leakage of electromagnetic signals in the conductor and medium, respectively. By substituting these parameters into the characteristic impedance formula, the frequency-dependent impedance characteristics of the transmission line can be obtained. The calculation formula of the characteristic impedance reflects the complex behavior of electromagnetic signals in the high-frequency wire harness, especially under high-frequency conditions, as various effects on electromagnetic waves in the medium and conductor are enhanced, and the impedance characteristics show strong frequency dependence. By calculating the characteristic impedance Z cThe formula can effectively describe the behavior of the transmission line during high-frequency signal propagation, including signal attenuation, energy loss, and reflection. The R(ω) + jωL(ω) in the numerator represents the combined effect of resistance and inductance during electromagnetic signal transmission. The frequency-dependent resistance R(ω) represents the energy loss of the conductor to the signal. At high frequencies, due to the skin effect, the current is concentrated on the surface of the conductor, resulting in increased surface loss. The frequency-dependent inductance L(ω) describes the magnetic field effect of the transmission line under the action of high-frequency signals. Inductive effect will cause the signal to interact with the magnetic field during transmission, thereby exerting a counterforce on the change of current. The complex form of this part makes the impedance formula better simulate the characteristics of high-frequency signals under the dual action of electric field and magnetic field in the conductor. The complex term jωL(ω) contains the angular frequency ω, which indicates that the effect of inductance increases with the increase of frequency, so the inductive effect on the signal is more significant under high-frequency conditions. Overall, this part reflects the influence of the conductor characteristics in the transmission line on signal propagation.

[0078] The G(ω) + jωC(ω) in the denominator represents the influence of the medium on the signal, where the frequency-dependent conductance G(ω) describes the leakage characteristics of the medium, which is the energy loss caused by the leakage of the medium during signal transmission. The frequency-dependent capacitance C(ω) describes the coupling effect of the electric field between conductors, i.e., the influence of the distribution of the electric field in the transmission line on signal propagation. Under high-frequency conditions, the distribution of the electric field in space depends not only on the geometry of the transmission line, but also on the dielectric properties of the surrounding medium. The complex term jωC(ω) indicates the frequency dependence of the capacitance effect, and as the frequency increases, the coupling effect of the capacitance on signal propagation also increases. The introduction of the capacitance term makes the model truly reflect the electric field coupling and energy storage effect between conductors. The propagation constant γ(ω) is another key part of the characteristic impedance formula, which describes the attenuation and phase change of the signal during transmission in the transmission line. The propagation constant is calculated by combining the equivalent transmission line parameters, defined as The propagation constant is used in the formula to represent the attenuation factor of the signal, which is essentially the overall impedance experienced by the high-frequency signal in the transmission line. The real part of the propagation constant represents the degree of attenuation of the signal during spatial propagation, while the imaginary part represents the phase change of the signal. The degree of attenuation determines the speed of energy loss during signal transmission, while the phase change reflects the change in speed and relative position of the electromagnetic wave during transmission. The size of the propagation constant directly affects the attenuation characteristics of the signal in the transmission line. The larger the propagation constant, the faster the signal attenuates, and the more obvious the phase change. The exponential term exp(-γ(ω)X) in the formula describes the attenuation of the signal over the length X of the transmission line. Since the propagation constant contains frequency dependence, as the frequency changes, the rate of signal attenuation in the transmission line will also change. This exponential term reflects the overall energy loss of the signal over the length X of the transmission line, i.e., the electric field strength of the signal will gradually weaken in an exponential manner after passing through a transmission line with a length of X. The introduction of this term not only takes into account the effect of transmission line length, but also integrates the effect of the propagation constant on signal attenuation, making the calculation results more close to the actual situation in high-frequency environment. This part is of great significance for long-distance signal transmission, especially in high-frequency conditions, where the attenuation effect of the signal during transmission will become more pronounced. The calculated results of the characteristic impedance can not only be used to judge the electromagnetic compatibility of the transmission line, but also be used to analyze the reflection of the signal. When the characteristic impedance of the transmission line does not match the load impedance, the signal will reflect on the transmission line, causing part of the energy to return to the source, thereby reducing the transmission efficiency of the system and possibly causing interference. Therefore, by optimizing the characteristic impedance, we can achieve matching with the load impedance, thereby minimizing reflection and improving the transmission efficiency of the system. The frequency dependence of the characteristic impedance also makes it exhibit different transmission characteristics at different frequencies, especially in high-frequency conditions, where the reflection and interference of the signal are more complex, so the calculation of the characteristic impedance is crucial for the optimal design of high-frequency wire bundles.

[0079] In step 3, the cross-talk voltage between adjacent wire bundles in the new energy high-frequency wire bundle is analyzed and calculated according to the frequency-dependent characteristic impedance by the following formula:

[0080]

[0081] where Z0 is the nominal characteristic impedance; M 12 M(ω) is the mutual inductance, which represents the degree of electromagnetic coupling between two wire bundles, and it is the mutual inductance of adjacent wire bundles at frequency ω; V xt V(r,ω) is the cross-talk voltage at spatial point r at a given frequency ω.

[0082] Specifically, in the formula, the cross-talk voltage V xt(r, ω) is the voltage at spatial point r at frequency ω. The generation of crosstalk voltage is mainly determined by the characteristic impedance Z c (ω) of the wire bundle, the mutual inductance M 12 (ω) of the adjacent wire bundle, and the rate of change of current on the wire bundle. The characteristic impedance Z c (ω) represents the propagation impedance characteristics of the signal in the transmission wire bundle, which has a direct impact on the size of the crosstalk voltage. When the characteristic impedance is high, the signal is prone to reflection during transmission, thereby generating a larger electromagnetic interference on the adjacent wire bundle. Therefore, the ratio of the crosstalk voltage to the characteristic impedance plays a regulating role in the formula, where Z0 is the nominal characteristic impedance of the system, representing the ideal impedance value. Through this ratio, the size of the impact of the actual characteristic impedance deviating from the ideal impedance on the crosstalk voltage can be analyzed. The mutual inductance coefficient M 12 (ω) is a crucial parameter in crosstalk calculation, which represents the coupling strength between two adjacent wire bundles. Under high frequency conditions, the electromagnetic coupling between wire bundles increases with frequency, so the mutual inductance coefficient also shows obvious frequency dependence. Mutual inductance reflects how the current change of one wire bundle induces a voltage in the other adjacent wire bundle. The higher the mutual inductance coefficient, the stronger the coupling between the wire bundles, and the more easily the current change in the adjacent wire bundle affects the signal of the other wire bundle, resulting in a larger crosstalk voltage. The size of the mutual inductance coefficient depends on the distance, geometric arrangement, material properties, and frequency characteristics between the wire bundles. The closer the distance between the adjacent wire bundles, the larger the mutual inductance value, and the more significant the impact of crosstalk voltage. Therefore, the calculation of the mutual inductance coefficient is crucial for accurately predicting the crosstalk voltage, and by adjusting the arrangement and distance of the wire bundles, the size of the crosstalk can be effectively controlled.

[0083] The rate of change of current The time-varying situation of high-frequency signals in adjacent wire bundles is reflected. Under high-frequency conditions, the current changes rapidly with time, and the higher the rate of change, the more intense the electromagnetic field changes, thus producing stronger interference on adjacent wire bundles. The current rate of change term explains the influence of the transient characteristics of high-frequency signals on crosstalk, and the rapid change of transient current will cause violent fluctuations in the surrounding space electromagnetic field, thus inducing voltage fluctuations in adjacent wire bundles through mutual inductance coupling. Therefore, the introduction of this term further embodies the contribution of high-frequency transient current to the crosstalk voltage. The propagation constant γ(ω) is a parameter that describes the propagation characteristics of signals in transmission lines, which includes the attenuation and phase change of signals. The attenuation factor in the propagation constant describes the gradual weakening of the signal as the propagation distance increases, especially in long-distance propagation, the energy of the signal will gradually attenuate. This attenuation effect is reflected in the exponential term exp(-γ(ω)|r-z'|) in the formula, which describes the degree of attenuation of the signal during propagation between two points. The signal gradually weakens due to the influence of resistance and inductance during propagation, and the longer the propagation distance, the more obvious the attenuation, so the intensity of interference between adjacent wire bundles will also decrease with the increase of distance. The introduction of the exponential attenuation term ensures that the calculation result of crosstalk voltage under long-distance conditions conforms to the actual physical attenuation law. The integral term represents the accumulation of all positions on the transmission line length X, which is used to calculate the interference accumulation effect of adjacent wire bundles on the entire transmission line length. Since the change of current will produce different electromagnetic field distribution at different positions of the transmission line, the integral can accumulate the contribution of each segment on the transmission line length to the crosstalk voltage. In other words, the integral process makes the calculation of crosstalk voltage cover the comprehensive influence of all positions on the transmission line, so as to obtain an overall interference value. This integral method not only can capture the electromagnetic interference at local positions, but also can consider the influence of transmission line length on crosstalk voltage, especially in the case of long transmission line, the integral term can reflect the cumulative effect of interference. Through the combination of the above terms, the calculation formula of crosstalk voltage comprehensively describes the electromagnetic interference distribution of high-frequency wire bundles in actual operation. The interaction of frequency-dependent characteristic impedance, mutual inductance coefficient, current rate of change, propagation constant and transmission line length makes the crosstalk voltage accurately reflect the interference intensity at different frequencies and different positions. The electromagnetic compatibility design of high-frequency wire bundles needs to find a balance between these parameters to effectively control the crosstalk. This calculation formula provides a theoretical basis, so that designers can reduce the crosstalk effect by adjusting the characteristic impedance, increasing the distance between wire bundles or changing the arrangement of wire bundles, so as to optimize the electromagnetic compatibility of high-frequency wire bundles.

[0084] In step 3 of embodiment 7, the radiation field of the new energy high-frequency wire bundle is calculated according to the crosstalk voltage by the following formula:

[0085]

[0086] where E rad (r,ω) represents the radiation field at spatial point r under a given frequency ω after adding the shielding layer; k is the wave number; k is the wave vector.

[0087] Specifically, the radiation field E rad (r,ω) represents the electric field intensity at spatial point r under a given frequency ω. This electric field intensity is directly induced by the crosstalk voltage V xt (r,ω) generated by the transmission line, and the crosstalk voltage represents the electromagnetic coupling effect between adjacent wire bundles, and such coupled signals form a radiation field in space. Since the electromagnetic radiation of high-frequency wire bundles has fluctuations in frequency, the radiation characteristics need to be comprehensively analyzed through frequency, spatial distance, and transmission line characteristics. The combination of parameters in this formula enables the calculation of the radiation field to accurately reflect the electromagnetic intensity at different spatial points. In the formula, the term represents the initial excitation coefficient of the radiation field, where j represents the imaginary unit, ω is the angular frequency, and μ0 is the vacuum permeability. This coefficient plays an important role in the calculation of the radiation field. The introduction of the angular frequency ω indicates that the electric field intensity increases with the increase of frequency, and the higher the frequency, the greater the intensity of the radiation field. The magnetic permeability μ0 describes the propagation ability of electromagnetic waves in vacuum, which affects the propagation behavior of electromagnetic fields in space. The imaginary form of this term indicates that the radiation field contains phase information, and the imaginary unit j indicates that the phase of the radiation field fluctuates with time, which is determined by the fluctuation characteristics of high-frequency signals. Through this coefficient, the initial intensity and phase information of the radiation field can be accurately described. The component in the formula is the ratio of the crosstalk voltage to the frequency-dependent characteristic impedance, which represents the influence of the crosstalk voltage on the intensity of the radiation field. The characteristic impedance Z c (ω) is the impedance value of the transmission line at frequency ω, and a larger characteristic impedance means that the transmission line imposes greater restrictions on the change of current, thereby reducing the radiation of external electric fields. The greater the crosstalk voltage, the greater the intensity of the electric field radiation. By calculating the ratio of the crosstalk voltage to the characteristic impedance, the radiation characteristics of the wire bundle at different frequencies can be evaluated, especially in frequency bands where the characteristic impedance changes significantly, the intensity of the radiation field will produce greater fluctuations.

[0088] The radiation field formula also contains a term related to the propagation distance, i.e. where k is the wave number, |r - r'| represents the distance between the spatial points r and r'. The wave number k is the ratio of frequency to the speed of light, which describes the propagation characteristics of electromagnetic waves. As the propagation distance |r - r'| increases, the electric field strength gradually decays, which is achieved by the denominator term |r - r'|. The denominator term reflects the decay relationship of the radiation field, that is, the electric field strength decreases with the increase of the propagation distance, which conforms to the inverse proportion decay characteristics of electromagnetic waves in free space. The exponential term exp(-jk|r - r'|) reflects the phase change and frequency dependence of electromagnetic waves. Since electromagnetic waves experience periodic fluctuations when propagating in space, the change in phase directly determines the direction and amplitude of the electric field. The imaginary exponential form of this term reflects the phase decay of the radiation field with the propagation distance. Finally, the integral term represents the accumulation along the length of the transmission line. This integral superimposes the radiation intensities at different positions in space, thus obtaining the overall contribution of the line bundle system to the spatial radiation field. During the transmission of high-frequency signals, the contributions of crosstalk voltages at different positions to the radiation field are not the same, so by integrating these contributions at different positions, a comprehensive radiation intensity distribution is formed. This integration process ensures the accuracy of the radiation field intensity in space, especially under the condition of a long transmission line, through integration, the propagation and distribution of electromagnetic fields in space can be more comprehensively described.

[0089] In step 3, the shielding effectiveness of the new energy high-frequency line bundle is calculated according to the radiation field by the following formula:

[0090]

[0091] where D is the thickness of the shielding layer of the new energy high-frequency line bundle; SE(ω) is the shielding effectiveness at frequency ω, with units of decibels; E0(r,ω) is the radiation field at spatial point r at frequency ω without shielding; α(ω) represents the attenuation constant at frequency ω, which determines the absorption intensity of the shielding layer to electromagnetic waves, and is a set value.

[0092] Specifically, the first term in the formula describes the attenuation of the radiation field in the shielding layer. E rad (r,ω) is the radiation field intensity at spatial point r after installing the shielding layer, and E0(r,ω) represents the radiation field intensity without shielding. By calculating the ratio of the two, the attenuation effect of the shielding layer on electromagnetic waves at that spatial point can be obtained. The logarithmic form of this term means that the shielding effectiveness is measured in decibels (dB), which is convenient for intuitively evaluating the effect of the shielding layer. The higher the decibel value of the shielding effectiveness, the better the attenuation effect of the shielding layer, the smaller the intensity of the radiation field after the shielding layer, and the lower the electromagnetic interference. This part of the calculation directly reflects the shielding ability of the shielding layer to electromagnetic waves, providing guidance for the design of shielding materials and the optimization of shielding layer thickness. The second term in the formula represents the influence of material properties within the shielding layer on the strength of electromagnetic wave absorption. The attenuation constant a(ω) in this term is a set value that reflects the absorption ability of the shielding layer material at frequency ω. The penetration depth and absorption characteristics of electromagnetic waves vary at different frequencies, so the attenuation ability of the shielding layer material also has frequency dependence. The larger the attenuation constant a(ω), the stronger the absorption ability of the shielding material for electromagnetic waves, thereby more effectively reducing the radiation field strength. In this term, represents the influence of the magnetic permeability μ r and electrical conductivity σ c of the material on the shielding effectiveness. The magnetic permeability μ r represents the magnetic permeability of the material relative to vacuum, and a higher magnetic permeability can enhance the absorption of the magnetic field by the shielding material, thereby improving the shielding effectiveness. On the other hand, the electrical conductivity σ c describes the electrical conductivity of the material, and a material with higher electrical conductivity has stronger reflection ability for electromagnetic waves, effectively reducing the penetration and propagation of electromagnetic waves, thus providing better shielding. By combining the magnetic permeability and electrical conductivity, the absorption and reflection characteristics of the shielding material for electromagnetic waves can be comprehensively reflected, thereby accurately estimating its shielding effectiveness. The integral term represents the influence of the characteristic impedance Z c (ω) within the shielding layer thickness D on the shielding effectiveness. As the shielding layer thickness D increases, the path of electromagnetic waves within the shielding layer becomes longer, and such path lengthening leads to greater attenuation, thereby enhancing the shielding effect. This integration process actually describes the cumulative effect of the shielding layer thickness on electromagnetic wave absorption. The characteristic impedance |Z c (ω)| as a frequency-dependent impedance value reflects the resistance experienced by electromagnetic waves at different frequencies. A higher characteristic impedance means that electromagnetic waves are more difficult to propagate in the shielding layer, and such a shielding material has stronger reflection and absorption ability for electromagnetic waves. Therefore, by integrating the shielding layer thickness, the electromagnetic compatibility performance of the shielding layer at different thicknesses can be accurately described.

[0093] In step 4 of Example 9, the constraint condition is set by the following formula:

[0094] |E rad (r,ω)|<E lim ;

[0095] |V xt (z,ω)|<V lim ;

[0096] SE(ω)>SE min ;

[0097] |Z c (ω)-Z0|<ΔZ max ;

[0098] where E lim is the set radiation limit; V lim is the set crosstalk limit; SE ref is the target shielding effectiveness; and ΔZ max is the set characteristic impedance threshold. The objective function is defined as:

[0099]

[0100] min{EMC total};

[0101] where EMC total is the performance metric; ω1is the set lower frequency limit; and ω2is the set upper frequency limit.

[0102] Specifically, in the constraint conditions of the formula, first is the limit of the radiation field intensity,

[0103] E rad (r, ω) | < E lim , where E lim is the radiation limit. This limit is used to control the radiation field intensity of the wire harness system under high frequency conditions, ensuring that the system does not produce excessive electromagnetic interference to surrounding equipment. By limiting the radiation field intensity within the set radiation limit, unnecessary radiation interference of the system under high frequency can be prevented, and the electromagnetic compatibility performance is improved. The second constraint condition is the limit of the crosstalk voltage |V xt (z, ω) | < V lim , where V lim is the set crosstalk limit. The crosstalk voltage reflects the electromagnetic coupling between adjacent high-frequency wires, and a higher crosstalk voltage will cause increased interference between adjacent wires. Therefore, by setting the limit of the crosstalk voltage, the mutual interference of high-frequency signals between different wires can be effectively controlled, thereby ensuring the signal integrity of the transmission line. The third constraint condition is the limit of the shielding effectiveness SE(ω) > SE min , where SE min is the minimum requirement for shielding effectiveness. Shielding effectiveness represents the suppression ability of the shielding layer to high-frequency electromagnetic waves, and higher shielding effectiveness means that the shielding layer can effectively absorb or reflect electromagnetic waves, reducing the radiation intensity of electromagnetic interference. This constraint condition ensures that the design of the shielding layer can maintain sufficient shielding effectiveness under high-frequency conditions, thereby effectively suppressing the leakage of electromagnetic waves. The last constraint condition |Z c (ω) - Z0| < ΔZ max is used to control the deviation of the characteristic impedance, where Z0is the ideal characteristic impedance of the system, and ΔZ maxis the allowable deviation range of the characteristic impedance. The characteristic impedance of the high-frequency wire harness is an important parameter to maintain stability and matching during signal transmission. Mismatched impedance can cause signal reflection and increased transmission loss. By controlling the deviation of the characteristic impedance, signal reflection and loss during transmission can be effectively reduced, ensuring the stability of high-frequency signals during transmission.

[0104] On the basis of these constraints, the objective function EMC total is defined, which comprehensively measures the electromagnetic compatibility performance of the system. This objective function includes the radiation field intensity, crosstalk voltage, and shielding effectiveness into a comprehensive evaluation system. Through integral calculation, the objective function performs weighted and normalized processing on each index within the set frequency range (from ω1 to ω2), forming a comprehensive electromagnetic compatibility performance index. Specifically, the radiation field intensity |E rad (ω)| 2 and the crosstalk voltage |V xt (ω)| 2 are limited by the square and normalization, which ensures that different performance indicators can be compared in the same evaluation system. In addition, the shielding effectiveness SE(ω) is normalized by the target effectiveness SE ref , ensuring that the effects of the shielding layer at different frequencies can be accurately included in the evaluation system. The optimization goal of the objective function is to minimize EMC total , i.e., to reduce the impact of electromagnetic interference, so that the system achieves the best electromagnetic compatibility performance in a high-frequency environment. By minimizing this comprehensive performance index, overall control of electromagnetic interference can be achieved. The integral calculation in the formula ensures the overall compatibility performance of the system within the set frequency range, rather than the electromagnetic characteristics at a single frequency point. By controlling the radiation, crosstalk, and shielding effectiveness at different frequencies, optimal design of full-band electromagnetic compatibility can be achieved. Ultimately, the combination of this objective function and constraints enables the system to be optimized through design, ensuring low radiation field intensity, small crosstalk effect, and sufficient shielding effectiveness under high-frequency conditions. The results of the optimization provide precise data support for the design of new energy high-frequency wire harnesses, enabling the system to operate while meeting all electromagnetic compatibility requirements.

[0105] It will be obvious to a person skilled in the art that the application is not limited to the details of the above-described exemplary embodiments, but that the application can be implemented in other concrete forms without deviating from the spirit or the basic characteristics of the application. The embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the application being defined by the appended claims rather than by the above Description, which is therefore intended merely as a specification. All changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference signs in the claims should not be construed as limiting the claim concerned. Furthermore, it is to be noted that the term "comprising" does not exclude other elements or steps, that the term "a" or "an" does not exclude a plurality, and that a single processor or other unit can fulfil the functions of several units recited in the claims. The terms first, second and the like do not denote any ordering, but rather are used as names for naming different units.

Claims

1. A new energy high-frequency wire harness design method based on electromagnetic compatibility optimization, characterized in that, The method comprises: Step 1: establishing a distributed electromagnetic source model of the new energy high-frequency wire harness to obtain electromagnetic source intensity of the new energy high-frequency wire harness at each spatial point; and calculating spatial electromagnetic field intensity based on the electromagnetic source intensity; Step 2: calculating equivalent transmission line parameters of the new energy high-frequency wire harness based on the spatial electromagnetic field intensity; and calculating frequency-variable characteristic impedance of the new energy high-frequency wire harness based on the equivalent transmission line parameters; Step 3: analyzing crosstalk between adjacent wire harnesses in the new energy high-frequency wire harness according to the frequency-variable characteristic impedance to calculate crosstalk voltage; calculating a radiation field of the new energy high-frequency wire harness according to the crosstalk voltage; and calculating shielding effectiveness of the new energy high-frequency wire harness according to the radiation field; Step 4: setting a constraint condition and establishing a target function under the constraint condition according to Step 1, Step 2 and Step 3, and finding a corresponding optimal design parameter vector of the new energy high-frequency wire harness by iteratively solving the target function; and designing the new energy high-frequency wire harness through the optimal design parameter vector; elements of the optimal design parameter vector include: a number of current sources of the new energy high-frequency wire harness, frequency-variable resistance, frequency-variable inductance, frequency-variable capacitance, frequency-variable conductance, shielding layer thickness and wire harness current; In Step 1, the distributed electromagnetic source model of the new energy high-frequency wire harness is established by the following formula to obtain electromagnetic source intensity of the new energy high-frequency wire harness at each spatial point: ； wherein, denotes the electromagnetic source strength at a given frequency at a spatial point ; is the number of current sources of the new energy high-frequency wire harness; is an integer subscript index; is the current intensity of the th current source; is the attenuation factor of the current source intensity in the process of spatial propagation, to simulate the square inverse distance attenuation characteristic of the current source to the spatial point is the position vector of the th current source; is a time variable; is the imaginary symbol; denotes the curl operation item of the magnetization ; is the magnetization at the th current source, is the curl operator, which represents the magnetization effect of the magnetic field generated by the current source on the surrounding area, and the unit vector denotes the direction from the current source position to the spatial point ; In Step 1, the spatial electromagnetic field intensity is calculated based on the electromagnetic source intensity by the following formula: ； wherein, denotes the given frequency denotes the spatial electromagnetic field strength at a spatial point ; skin depth defines the penetration depth of the electric field in the medium at a frequency ; is a position integration variable; is the corresponding propagation Green's function at a position integration variable; is the corresponding form at a position integration variable; is the corresponding form at a position integration variable; is the spatial range of the new energy high-frequency wire harness.

2. The new energy high-frequency wire harness design method based on electromagnetic compatibility optimization according to claim 1, characterized in that, In Step 2, the equivalent transmission line parameters of the new energy high-frequency wire harness are calculated based on the spatial electromagnetic field intensity by the following formula: ； in, The equivalent transmission line parameters for high-frequency harnesses in new energy sources; For a given frequency Frequency conversion; The magnitude of the electric field strength; The conductivity of the conductor in the high-frequency wiring harness for new energy sources; This indicates the surrounding closed path of the high-frequency wiring harness for new energy sources. This represents the distance integral variable along the surrounding closed path of the high-frequency harness in the new energy source. For a given frequency Frequency-converting inductors; Permeability of free space; The diameter of the outer conductor of the high-frequency harness for new energy sources; The diameter of the inner conductor of the high-frequency wire harness for new energy sources; The relative permeability of the new energy high-frequency wire harness represents the magnetic permeability of the material of the new energy high-frequency wire harness relative to vacuum. The relative permittivity of the high-frequency wire harness for new energy sources represents the capacitance characteristic of the material of the high-frequency wire harness for new energy sources relative to vacuum. It is the vacuum permittivity; For a given frequency Frequency-converting capacitors; For a given frequency Frequency-dependent conductivity; denoted as ν, where ν is the electrical conductivity of the medium.

3. The new energy high-frequency wire harness design method based on electromagnetic compatibility optimization according to claim 2, characterized in that, In Step 2, the frequency-variable characteristic impedance of the new energy high-frequency wire harness is calculated based on the equivalent transmission line parameters by the following formula: ； wherein, is the frequency-dependent characteristic impedance at a given frequency ; is the propagation constant at a given frequency ; ; is the length of the new energy high-frequency wire harness.

4. The new energy high-frequency wire harness design method based on electromagnetic compatibility optimization according to claim 3, characterized in that, In Step 3, the crosstalk voltage is calculated by analyzing the crosstalk between adjacent wire harnesses in the new energy high-frequency wire harness according to the frequency-variable characteristic impedance by the following formula: ； wherein, is the nominal characteristic impedance; is the mutual inductance coefficient, representing the degree of electromagnetic coupling between two wire bundles, which is the mutual inductance between adjacent wire bundles at a frequency ; is the crosstalk voltage at a spatial point for a given frequency .

5. The new energy high-frequency wire harness design method based on electromagnetic compatibility optimization according to claim 4, characterized in that, In Step 3, the radiation field of the new energy high-frequency wire harness is calculated according to the crosstalk voltage by the following formula: ； wherein, represents the given frequency the radiation field at a spatial point ; is the wave number; is the wave vector.

6. The new energy high-frequency wire harness design method based on electromagnetic compatibility optimization according to claim 5, characterized in that, In Step 3, the shielding effectiveness of the new energy high-frequency wire harness is calculated according to the radiation field by the following formula: ； wherein, is the thickness of the shielding layer of the new energy high-frequency wire harness; is the shielding effectiveness at a frequency , unit: decibel; is the radiation field at a spatial point without shielding at a frequency ; represents the attenuation constant at a frequency , which determines the absorption intensity of the shielding layer to the electromagnetic wave, and is a set value.

7. The new energy high-frequency wire harness design method based on electromagnetic compatibility optimization according to claim 6, characterized in that, In Step 4, the constraint condition is set by the following formula: ； wherein, is a set radiation limit; is a set crosstalk limit; is a target shielding effectiveness; is a set characteristic impedance threshold; the objective function is defined as: ； ； wherein is a performance indicator; is a set lower frequency limit; is a set upper frequency limit.

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