Electromechanical system integrated broadband electromagnetic radiation characteristic modeling method based on cable current and electrical equipment near-field test data

Abstract

The invention discloses an electromechanical system integrated broadband electromagnetic radiation characteristic modeling method based on cable current and electrical equipment near field test data, comprising the following steps: 1) modeling broadband radiation characteristics of each strong electromagnetic equipment of an electromechanical system, 2) modeling the wide-frequency-band radiation characteristics of interconnection cables among the strong electromagnetic devices of the electromechanical system to obtain a radiation electric field # imgabs1 # generated by the cables; 3) carrying out vector superposition on the radiation electric field # imgabs2 # generated by the strong electromagnetic devices and the radiation electric field # imgabs3 # generated by the cables to obtain a radiation electric field # imgabs2 # generated by the strong electromagnetic devices and a radiation electric field # imgabs1 # generated by the cables, and carrying out vector superposition on the radiation electric field # imgabs2 # generated by the strong electromagnetic devices and the radiation electric field # imgabs3 # generated by the cables; and 4) superposing the radiation electric field # imgabs5 # of the electromechanical system with the relative error between the radiation electric field and the test electric field to obtain a radiation electric field test value of the electromechanical system. According to the method, the system-level integrated radiation interference characteristic model of the electromechanical system can be effectively established, and the radiation field distribution of the electromechanical system in a large equipment platform can be quickly predicted.

Description

Technical Field

[0001] The present invention relates to the field of electromagnetic compatibility prediction, and in particular to a method for modeling the integrated broadband electromagnetic radiation characteristics of an electromechanical system based on cable current and near-field test data of electrical equipment. Background Art

[0002] The radiation interference of complex electrical systems mainly comes from strong electromagnetic devices and the cable networks connected thereto. At present, two methods are often used for the research on the radiation of cables and electromechanical systems, namely the full-wave analysis method and the approximate calculation method based on the multi-conductor transmission line (MTL) theory and the dipole array theory. The full-wave analysis method has the advantage of high accuracy, but with the diversification of cable networks, its disadvantages of long modeling time and large calculation amount limit the efficient calculation of cable radiation. The calculation method based on the multi-conductor transmission line theory and the dipole array theory equivalent the cable to a distributed parameter transmission line network, which can greatly reduce the calculation amount and shorten the calculation time on the premise of ensuring the calculation accuracy, and realizes efficient modeling analysis. However, at present, when using this approximate calculation method, it is mostly limited to the ideal straight and uniform transmission line model. This idealized model is not applicable to the application scenarios of constructing the radiation interference model of the electromechanical system composed of actual long cables and electromagnetic devices. Therefore, the following problems exist:

[0003] (1) The cables in actual application scenarios are often bent, the routing positions will also change, and there are various connectors in the actual cable network, which will inevitably affect the distribution of interference signals on the cables. However, the existing calculation models rarely analyze and consider these problems, and there is no corresponding modeling analysis method. (2) The electromagnetic radiation of the actual electromechanical system is jointly formed by the interconnected cables and electrical equipment, and the cable radiation and the electrical equipment radiation affect each other. However, the existing research often only focuses on the cable radiation model, lacking a modeling method for the integration of the radiation characteristics of electrical equipment and cables. (3) The interconnected cables in some actual electromechanical systems often span multiple compartments, with complex routing paths and layout positions, and are relatively long, resulting in the inability to perform overall surface data testing on the radiation planes of the equipment and cables. The electromagnetic radiation interference characteristic modeling method based on the overall near-field test data is not applicable, lacking a modeling method for the integration of the radiation characteristics of electrical equipment and cables when the cables in the electromechanical system are relatively long.

[0004] Therefore, at the beginning of the design of an electro - electrical system, it is necessary to propose an efficient and accurate modeling method for the radiation characteristics of complex cable networks and equipment in an electromechanical system, so as to evaluate the electromagnetic interference (EMI) level of electrical equipment and cable networks, and thus support the work of cable selection and routing, equipment layout optimization, and EMC index allocation, design, and rectification of electromechanical systems and the platforms they are on, in order to improve the overall EMC performance of electromechanical systems and the platforms they are on. Summary of the Invention

[0005] The object of the present invention is to provide an integrated broadband electromagnetic radiation characteristic modeling method for an electromechanical system based on cable current and near - field test data of electrical equipment, including the following steps:

[0006] 1) Model the wide - band radiation characteristics of each strong electromagnetic device in the electromechanical system to obtain the radiation electric field generated by the strong electromagnetic device

[0007] 2) Model the wide - band radiation characteristics of the interconnecting cables between each strong electromagnetic device in the electromechanical system to obtain the radiation electric field generated by the cables

[0008] 3) Perform vector superposition on the radiation electric field generated by the strong electromagnetic device and the radiation electric field generated by the cables to obtain the radiation electric field of the electromechanical system

[0009] Furthermore, in step 1), the steps of modeling the wide - band radiation characteristics of each strong electromagnetic device in the electromechanical system include:

[0010] 1.1) Obtain the near - field data of each strong electromagnetic device in the electromechanical system at preset frequency test points within a wide band through near - field measurement methods; the preset frequency test points are denoted as f0, f1, …, f s-1 and f0 < f1 < … < f s-1 ;

[0011] 1.2) Use the ADE algorithm to minimize the error between the radiation electric field generated by the dipole array and the test electric field, thereby establishing an optimal equivalent dipole array at different preset frequency test points;

[0012] 1.3) Solve the optimal equivalent dipole array to determine the polynomial coefficients of the wide - band dipole parameters, thereby establishing a wide - band model of the wide - band radiation characteristics of each strong electromagnetic device.

[0013] Furthermore, in step 1.2), the steps of establishing an optimal equivalent dipole array at different preset frequency test points include:

[0014] 1.2.1) Parameter and population initialization;

[0015] 1.2.2) Set the fitness function F, i.e.:

[0016]

[0017] 1.2.3) Calculate the crossover probability factor CRi and the scaling factor Fi for each individual in each generation of the population, and store them in the crossover probability factor set SCR and the scaling factor set SF respectively;

[0018] The crossover probability factor CRi and the scaling factor Fi are as follows:

[0019] CR i = randni(μ CR , 0.1)(2)F i = randci(μ F , 0.1)(3)

[0020] 1.2.4) Mutate the population individuals to obtain the mutated individuals;

[0021] The mutated individual v i,G is as follows:

[0022]

[0023] 1.2.5) In each dimension, perform a crossover operation on the mutated individual v i,G and the corresponding parent individual x i,G to obtain a new candidate solution individual u j,i,G , i.e.:

[0024]

[0025] 1.2.6) According to the fitness value, select the individual with better fitness between x i,G and u i,G as the parent individual x j,i,G of the next generation, i.e.:

[0026]

[0027] 1.2.7) Update the normal distribution expectation μ CR , the Cauchy distribution location parameter μ F adoptively, and return to step 1.2.3) until the fitness function value of the optimal population meets the preset termination iteration criterion or reaches the maximum number of iterations, and output the optimal dipole array.

[0028] The updated normal distribution expectation μ CR and the Cauchy distribution location parameter μF As follows:

[0029] μ CR μ = (1 - c)·μ CR + c·mean A (S CR )(7)

[0030]

[0031] Furthermore, in step 1.2.1), the steps for parameter and population initialization are as follows:

[0032] Set the maximum number of iterations to MaxGen;

[0033] Initialize the external archive population A as an empty set;

[0034] Initialize the crossover probability factor set SCR and the scaling factor set SF as empty sets;

[0035] Set the expectation μ of the normal distribution CR , the location parameter μ of the Cauchy distribution F , the probability p of the best individual in all individuals in each generation, and the control factor c;

[0036] Set the population size to Ns, the size of a population to NP, and the individual size to Dim;

[0037] Define the initial population as {x i,0 = (x 1,i,0 , x 2,i,0 ,..., x j,i,0 ,..., x Dim,i,0 ) | i = 1, 2,..., NP};

[0038] Among them, the individuals in the population are as follows:

[0039]

[0040] At the initial iteration G = 0, the j - th dimension x j,i,0 of the i - th individual is as follows:

[0041]

[0042] Furthermore, the optimal equivalent dipole array is as follows:

[0043]

[0044] Among them, the distance r, the coordinates x i',j' , y i',j' and z i',j' are as follows:

[0045]

[0046] Among them, K e , f1(r), and f2(r) are as follows:

[0047]

[0048] The matrix form of the optimal equivalent dipole array is as follows:

[0049]

[0050] In the absence of the ground, the conversion relationships y between the dipole moments Px, P z and P and the electric field and are as follows:

[0051]

[0052] In the presence of the ground, the conversion relationships y between the dipole moments Px, P z and P and the electric field and are as follows:

[0053]

[0054] In the absence of the ground, the conversion relationships y between the electric dipole moments Px, P z and P and the electric field and are as follows:

[0055]

[0056] In the presence of the ground, the conversion relationships y between the electric dipole moments Px, P z and P and the electric field and are as follows:

[0057]

[0058] In the absence of the ground, the conversion relationships y between the electric dipole moments Px, P z and P and the electric field and are as follows:

[0059]

[0060] When there is a ground plane, the conversion relationships between the electric dipole moments Px, P y and P z and the electric field are as follows: and are as follows:

[0061]

[0062] where r1 and r2 are as follows:

[0063]

[0064] Furthermore, in step 2), the steps of modeling the broadband radiation characteristics of the interconnection cables between the strong electromagnetic devices of the electromechanical system include:

[0065] 2.1) Measuring the terminal current data of the cable ports in the electromechanical system;

[0066] 2.2) Establishing an equivalent N-port model of the connector using the scattering parameter matrix of the connector in the interconnection cable;

[0067] 2.3) Calculating the per-unit-length parameter matrix and transmission matrix of the cable, and establishing the cable MTL equation, that is:

[0068]

[0069] 2.4) Obtaining the transmission parameter matrix of the bent cable, and cascading the transmission parameter matrices of the bent cable and the connector, so as to establish an arbitrary interconnection cable cascade model;

[0070] 2.5) Combining the cable boundary constraint conditions at the cable ports and the arbitrary interconnection cable cascade model, solving the cable MTL equation, obtaining the current distribution on the interconnection cables in the electromechanical system, and calculating the electric field radiation of the cable network using the dipole array theory, so as to model the broadband radiation characteristics of the interconnection cables between the strong electromagnetic devices of the electromechanical system.

[0071] Furthermore, in step 2.2), the scattering parameter matrix of the connector is as follows:

[0072]

[0073]

[0074] Furthermore, in step 2.4), the steps of establishing an arbitrary interconnection cable cascade model include:

[0075] 2.4.1) Divide the curved cable into multiple uniform cable sub-segments, thereby constructing the transmission matrix of the curved cable, that is:

[0076]

[0077] Among them, the transmission parameter matrix of the o-th uniform cable sub-segment is as follows:

[0078]

[0079] 2.4.2) Cascade the transmission parameter matrices of the curved cable and the connector to obtain:

[0080]

[0081] 2.4.3) Establish an arbitrary interconnect cable cascade model, that is:

[0082]

[0083] Among them, is the transmission parameter matrix of the connector, is the transmission parameter matrix of the cable in the k-th duct, is the equivalent transmission parameter matrix of all branches connected to node k.

[0084] Furthermore, in step 2.5), the steps for calculating the electric field radiation of the cable network include:

[0085] 2.5.1) Solve the cable current, that is:

[0086]

[0087] 2.5.2) Calculate the surface current distribution of the cable network, that is:

[0088]

[0089] 2.5.3) Equivalent each current-carrying cable segment to an electric dipole, and apply the dipole array theory to calculate the radiation field to obtain:

[0090]

[0091] 2.5.4) Calculate the total radiation electric field generated by the cable network, that is:

[0092]

[0093] In the formula, and are the total radiation electric fields generated by the real current segment and the image current segment on the cable network respectively, and They are the mirror image and the real electric field generated at the support end respectively.

[0094] The technical effect of the present invention is beyond doubt. The present invention proposes a hybrid modeling method for broadband electromagnetic radiation characteristics of electromechanical system integration that combines dipole array theory, Adaptive Differential Evolution (ADE) algorithm, and transmission line theory. It can effectively use the near-field data of the cable ends at both ports and strong electromagnetic devices in the electromechanical system within a limited number of frequency points to establish a system-level integrated radiation interference characteristic model of the electromechanical system, and can combine with 3D simulation software to quickly predict the radiation field distribution of the electromechanical system in a large equipment platform.

[0095] The beneficial effects of the present invention are as follows:

[0096] 1. The present invention provides a method for the broadband equivalent radiation interference model of an electromechanical system with cross-compartment layout based on cable port current and near-field test data of electrical equipment. It can make full use of the known information of the interconnected cable network (cable topology, load, etc.), and without relying on the internal structure of electrical equipment in the electromechanical system, etc., this method can be used to obtain its radiation source equivalent model, and it has strong applicability and is not limited to a certain type of electromechanical system;

[0097] 2. The present invention can make full use of the known information such as the cable type of the interconnected cable network in the electromechanical system. Only the near-field data of electrical equipment and the test data of cable ports in the electromechanical system need to be tested, which can not only greatly reduce the workload and difficulty of cable near-field testing, but is especially suitable for radiation interference modeling of electromechanical systems containing cross-compartment and very long interconnected cables.

[0098] 3. The present invention effectively uses the near-field data of the cable ends at both ports and strong electromagnetic devices in the electromechanical system within a limited number of frequency points to establish a broadband radiation interference model of the electromechanical system, which can be used to accurately standardize the broadband interference characteristics of the electromechanical system.

[0099] 4. Based on the radiation interference model of the electromechanical system established by the method proposed in the present invention, it is convenient to combine with 3D simulation software such as FEM to quickly predict the radiation field distribution of the electromechanical system in each compartment of the large equipment platform. Description of the Drawings

[0100] Figure 1 It is a flowchart of the hybrid modeling method for broadband radiation characteristics based on dipole array combination; Figure 2 It is a test schematic diagram; Figure 3 It is an N-port network; Figure 4 It is a schematic diagram of a complex interconnected cable network. Figure 5 It is a port network of a parallel branch cable; Figure 6is the mirror image of the current segment on the mirror plane; Figure 7 is the physical model of the electromechanical system; Figure 8 is the schematic diagram of modeling based on near-field data;

[0101] Figure 9 is the variation of the optimal dipole parameters with frequency; Figure 10 is the electric field radiation spectrum at (0mm, 0mm, 600mm); Figure 11 is the electric field distribution characteristics at z = 0.6m at different frequencies; Figure 12 is the electric field distribution at 350MHz obtained by CST simulation; Figure 13 is the electric field distribution at 350MHz obtained by the modeling method of the present invention Specific implementation manner

[0102] The present invention will be further described below with reference to the embodiments. However, it should not be understood that the scope of the above-mentioned subject matter of the present invention is limited to the following embodiments. Without departing from the above technical idea of the present invention, various substitutions and changes made according to the common general knowledge and customary means in the art shall be included within the protection scope of the present invention.

[0103] Embodiment 1:

[0104] See Figures 1 to 13 , a method for modeling the integrated broadband electromagnetic radiation characteristics of an electromechanical system based on cable current and near-field test data of electrical equipment, comprising the following steps:

[0105] 1) Model the broadband radiation characteristics of each strong electromagnetic device in the electromechanical system to obtain the radiation electric field generated by the strong electromagnetic device

[0106] 2) Model the broadband radiation characteristics of the interconnection cables between each strong electromagnetic device in the electromechanical system to obtain the radiation electric field generated by the cables

[0107] 3) Perform vector superposition on the radiation electric field generated by the strong electromagnetic device and the radiation electric field

[0108] Embodiment 2:

[0109] A method for modeling the integrated broadband electromagnetic radiation characteristics of an electromechanical system based on cable current and near-field test data of electrical equipment, the technical content is the same as that of Embodiment 1. Further, in step 1), the steps of modeling the broadband radiation characteristics of each strong electromagnetic device in the electromechanical system include:

[0110] 1.1) Obtain the near-field data of each strong electromagnetic device in the electromechanical system at the preset frequency test points within the broadband through the near-field measurement method; the preset frequency test points are denoted as f0, f1, …, f s-1 , and f0 < f1 < … < f s-1 ;

[0111] 1.2) Use the ADE algorithm to minimize the error between the radiation electric field generated by the dipole array and the test electric field, so as to establish the optimal equivalent dipole array at different preset frequency test points;

[0112] 1.3) Solve the optimal equivalent dipole array, determine the polynomial coefficients of the broadband dipole parameters, and thus establish the broadband model of the broadband radiation characteristics of each strong electromagnetic device.

[0113] Example 3:

[0114] An integrated broadband electromagnetic radiation characteristic modeling method for an electromechanical system based on cable current and near-field test data of electrical equipment, the technical content is the same as any one of Examples 1-2. Further, in step 1.2), the steps of establishing the optimal equivalent dipole array at different preset frequency test points include:

[0115] 1.2.1) Parameter and population initialization;

[0116] 1.2.2) Set the fitness function F, that is:

[0117]

[0118] where s is the number of frequency points, w is the wth frequency point calculated; N is the total number of points on the near-field plane at each frequency; t takes three components of x, y, and z. is the measured value of the t-component electric field of the qth calculation point at the wth frequency point; is the calculated value of the t-component electric field of the qth calculation point at the wth frequency point; Re and Im are respectively taking the real part and the imaginary part of the electric field;

[0119] 1.2.3) Calculate the crossover probability factor CRi and the scaling factor Fi of each individual in each generation of the population, and store them in the crossover probability factor set SCR and the scaling factor set SF respectively;

[0120] The crossover probability factor CRi and the scaling factor Fi are as follows:

[0121] CR i = randni(μ CR , 0.1)(2)F i = randci(μ F , 0.1)(3)

[0122] 1.2.4) Mutate the individuals in the population to obtain the mutated individuals;

[0123] The mutated individual v i,G is as follows:

[0124]

[0125] where x i,G is the G-th generation population. is randomly selected from the individuals with the top 100p% fitness values in the current population, where p ∈ (0, 1). x r1,G is randomly selected from the current individual, x r2,G is randomly selected from the union of the current population and the archive population A; x r2,G ≠ x r1,G ≠ x i,G ;

[0126] 1.2.5) In each dimension, perform a crossover operation on the mutated individual v i,G and the corresponding parent individual x i,G to obtain a new candidate solution individual u j,i,G , that is:

[0127]

[0128] In the formula, CR i is the crossover probability factor.

[0129] 1.2.6) According to the fitness value, select the individual with better fitness between x i,G and u i,G as the parent individual x j,i,G of the next generation, that is:

[0130]

[0131] 1.2.7) Update the normal distribution expectation μ CR and the Cauchy distribution location parameter μ F adoptively, and return to step 1.2.3) until the fitness function value of the optimal population meets the preset iteration termination criterion or reaches the maximum number of iterations, and output the optimal dipole array.

[0132] The updated normal distribution expectation μ CR and the Cauchy distribution location parameter μ F are as follows:

[0133] μ CR = (1 - c)·μ CR + c·mean A (S CR )(7)

[0134] Among them, c is a control factor, which has a strong ability to adapt to different problem-solving. c ∈ (0, 1), mean A (S CR ) represents the arithmetic mean of the elements of the set SCR.

[0135] Example 4:

[0136] A method for modeling the integrated broadband electromagnetic radiation characteristics of an electromechanical system based on cable current and near-field test data of electrical equipment. The technical content is the same as any one of Examples 1-3. Further, in step 1.2.1), the steps of parameter and population initialization are as follows:

[0137] Set the maximum number of iterations to MaxGen;

[0138] Initialize the external archive population A as an empty set;

[0139] Initialize the crossover probability factor set SCR and the scaling factor set SF as empty sets;

[0140] Set the expectation μ of the normal distribution CR , the location parameter μ of the Cauchy distribution F , the probability p of the best individual in each generation among all individuals, and the control factor c;

[0141] Set the population size to Ns, the size of one population to NP, and the individual size to Dim;

[0142] Define the initial population as {x i,0 = (x 1,i,0 , x 2,i,0 ,..., x j,i,0 ,..., x Dim,i,0 )|i = 1, 2,..., NP};

[0143] Among them, the individuals in the population are as follows:

[0144]

[0145] Among them, i refers to the serial number of the electric dipole, x i , y i and z i describe the position of the i-th electric dipole; and are the electric dipole moments in the three directions of the i-th electric dipole at the frequency f0 respectively; are the electric dipole moments in the three directions of the i-th electric dipole at the frequency f s-1 respectively; Re and Im represent the real part and the imaginary part of the complex value;

[0146] At the initial iteration \(G = 0\), the \(j\)-th dimension \(x\) of the \(i\)-th individual j,i,0 is as follows:

[0147]

[0148] where, and are the maximum and minimum boundaries that the individual can take in the \(j\)-th dimension, and \(rand(0, 1)\) is a random number uniformly distributed between 0 and 1.

[0149] Example 5:

[0150] A method for modeling the integrated broadband electromagnetic radiation characteristics of an electromechanical system based on cable current and near-field test data of electrical equipment. The technical content is the same as any one of Examples 1 - 4. Further, the optimal equivalent dipole array is as follows:

[0151]

[0152] where, \(P\) i',j',x , \(P\) i',j',y and \(P\) i',j',z are the electric dipole moment components of the \(j\)-th electric dipole in the \(x\), \(y\), and \(z\) directions in the \(i'\)-th dipole plane, respectively. Here, \(i = 1, 2, \cdots, N_i\), and \(N_i\) is the number of dipole planes. and are the electric fields in the \(x\), \(x\), and \(z\) directions at the \(j\)-th measurement point on the \(i\)-th near-field plane, respectively. \(j = 1, 2, \cdots, N_j\), and \(N_j\) is the number of measurement points on each scanning plane.

[0153] where, the distance \(r\), coordinates \(x\) i',j' , \(y\) i',j' and \(z\) i',j' are as follows:

[0154]

[0155] In the formula, \(x\) i',j' , \(y\) i',j' and \(z\) i',j' represent the \(x\), \(y\), and \(z\) coordinates of the \(j'\)-th electric dipole in the \(i'\)-th dipole plane, respectively; \(x\) i,j , \(y\) i,j and \(z\) i,j represent the \(x\), \(y\), and \(z\) coordinates of the \(j\)-th measurement point on the \(i\)-th near-field plane, respectively; \(r\) represents the distance between the measurement point and the dipole.

[0156] where, \(K\) e , \(f1(r)\), \(f2(r)\) are as follows:

[0157]

[0158] Among them, is the free space propagation constant, μ0 is the magnetic permeability of free space, ε0 is the permittivity of free space, and ω is the angular frequency; is the wave impedance of free space;

[0159] The matrix form of the optimal equivalent dipole array is as follows:

[0160]

[0161] In the formula, Px, P y and P z are the electric dipole moments in each direction of the dipoles in the electric dipole array respectively. and are the electric field values in the x, y, and z directions of the measurement point respectively; T e is the coefficient matrix;

[0162] When there is no ground, the conversion relationship y between the dipole moments Px, P z and P and the electric field and is as follows:

[0163]

[0164] When there is ground, the conversion relationship y between the dipole moments Px, P z and P and the electric field and is as follows:

[0165]

[0166] When there is no ground, the conversion relationship y between the electric dipole moments Px, P z and P and the electric field and is as follows:

[0167]

[0168] When there is ground, the conversion relationship y between the electric dipole moments Px, P z and P and the electric field and is as follows:

[0169]

[0170] In the absence of a ground plane, the conversion relationships between the electric dipole moments Px, P y and P z and the electric field are as follows: and are as follows:

[0171]

[0172] In the presence of a ground plane, the conversion relationships between the electric dipole moments Px, P y and P z and the electric field are as follows: and are as follows:

[0173]

[0174] where r1 and r2 are as follows:

[0175]

[0176] Example 6:

[0177] A method for modeling the integrated broadband electromagnetic radiation characteristics of an electromechanical system based on cable current and near-field test data of electrical equipment. The technical content is the same as any one of Examples 1-5. Further, in step 2), the steps for modeling the broadband radiation characteristics of the interconnection cables between the strong electromagnetic devices of the electromechanical system include:

[0178] 2.1) Measure the terminal current data of the cable ports in the electromechanical system;

[0179] 2.2) Establish an equivalent N-port model of the connector using the scattering parameter matrix of the connector in the interconnection cable;

[0180] 2.3) Calculate the per-unit-length parameter matrix and transmission matrix of the cable, and establish the cable MTL equation, that is:

[0181]

[0182] where R, L, C, and G are the per-unit-length resistance, inductance, capacitance, and conductance parameters, respectively; and are the column vectors of voltage and current, respectively; and are the impedance matrix and admittance matrix of the wire harness, respectively;

[0183] 2.4) Obtain the transmission parameter matrix of the bent cable, and cascade the transmission parameter matrices of the bent cable and the connector to establish an arbitrary interconnection cable cascade model;

[0184] 2.5) Combine the cable boundary constraint conditions of the cable port and the cascaded model of any interconnected cable, solve the MTL equation of the cable, obtain the current distribution on the interconnected cable in the electromechanical system, and calculate the electric field radiation of the cable network using the dipole array theory, so as to model the broadband radiation characteristics of the interconnected cables between the strong electromagnetic devices in the electromechanical system.

[0185] Example 7:

[0186] An integrated broadband electromagnetic radiation characteristic modeling method for an electromechanical system based on cable current and near-field test data of electrical equipment, the technical content is the same as any one of Examples 1-6. Further, in step 2.2), the scattering parameter matrix T of the connector C is as follows:

[0187]

[0188] where S UU , S UV , S VU and S VV are the elements of the scattering parameter matrix of the port network; A UU , B UV , C VU and D VV are the elements of the transmission matrix of the port network. V U and V V are the voltage matrices; I U and I V are the current matrices; a U and b U represent the incident wave and the reflected wave of the U port; a U = diag(a1,…,a U ); a V and b V represent the incident wave and the reflected wave of the V port; 1 is the identity matrix. Z U Z U is the impedance matrix of the U port, Z V is the impedance matrix of the V port, are the conjugates of Z U and Z V respectively; Z 0,i is the port impedance; is the conjugate of Z 0,i . J, G are intermediate matrices; g U , g V are parameter vectors; g 0_i is an intermediate parameter.

[0189] Example 8:

[0190] A method for modeling the integrated broadband electromagnetic radiation characteristics of an electromechanical system based on cable current and near-field test data of electrical equipment, the technical content is the same as any one of Embodiments 1-7. Further, in step 2.4), an arbitrary interconnected cable cascade model is established.

[0191] 2.4.1) Divide the curved cable into multiple uniform cable sub-segments, thereby constructing the transmission matrix of the curved cable, that is:

[0192]

[0193] Among them, the transmission parameter matrix of the o-th uniform cable sub-segment is as follows:

[0194]

[0195] In the formula, is the similarity diagonal matrix of the o-th uniform cable sub-segment, is the admittance matrix of the cable segment, is the propagation constant of the o-th segment of the uniform cable sub-segment; and are the elements of the transmission parameter matrix;

[0196] 2.4.2) Cascade the transmission parameter matrices of the curved cable and the connector to obtain:

[0197]

[0198] Among them, is the ratio of the input voltage to the input current of the branch line. and are the input voltage and input current of the branch line respectively; is the terminal voltage of the branch cable; is the terminating load of the branch cable, and are the elements of the transmission parameter matrix of the branch cable; 1 is the identity matrix; is the equivalent input impedance of the branch line; is the cascaded transmission parameter matrix;

[0199] 2.4.3) Establish an arbitrary interconnected cable cascade model That is:

[0200]

[0201] Among them, is the transmission parameter matrix of the connector, is the transmission parameter matrix of the cable of the k-th pipeline, is the equivalent transmission parameter matrix of all branches connected to node k.

[0202] Example 9:

[0203] A method for modeling the integrated broadband electromagnetic radiation characteristics of an electromechanical system based on cable current and near-field test data of electrical equipment. The technical content is the same as any one of Examples 1-8. Further, in step 2.5), the steps for calculating the electric field radiation of the cable network include:

[0204] 2.5.1) Solve the cable current, that is:

[0205]

[0206] In the formula, is the voltage; is the current;

[0207] 2.5.2) Calculate the surface current distribution of the cable network, that is:

[0208]

[0209] In the formula, α x 、α y 、α z are the component angles;

[0210] 2.5.3) Equivalent each cable current-carrying segment to an electric dipole, and apply the dipole array theory to calculate the radiation field, obtaining:

[0211]

[0212] Among them, (x i , y i , z i ) is the position of the i-th cable current-carrying segment, and r i is the distance between the i-th cable current-carrying segment and the electric field observation point; and are the x, y, and z component currents of the i-th cable current-carrying segment; Δx i , Δy i and Δz i are the lengths of the i-th current-carrying segment. The product of the current of the dipole and its size is the electric dipole moment. and are the electric fields in the x, y, and z directions generated by the i-th current-carrying segment respectively. ε is the external environmental dielectric constant, ω is the current angular frequency, β is the free space wave number, and Nz is the number of current-carrying segments;

[0213] Among them, the polar angle θ zi and azimuth angle of the i-th z-direction dipole current-carrying segment in the spherical coordinate system are as follows:

[0214]

[0215] The polar angle θ of the i-th current-carrying dipole segment in the y direction in the spherical coordinate system yi and the azimuth angle are as follows:

[0216]

[0217] The polar angle θ of the i-th current-carrying dipole segment in the x direction in the spherical coordinate system xi and the azimuth angle are as follows:

[0218]

[0219] 2.5.4) Calculate the total radiated electric field generated by the cable network That is:

[0220]

[0221] In the formula, and are the total radiated electric fields generated by the real current segments and the image current segments on the cable network respectively, and are the image and real electric fields generated by the support end respectively.

[0222] Example 10:

[0223] A method for modeling the integrated broadband electromagnetic radiation characteristics of an electromechanical system based on cable current and near-field test data of electrical equipment. The technical content is the same as any one of Examples 1-9. Further, calculate the relative error between the test value and the value calculated by this method to verify the accuracy of this method.

[0224] Example 11:

[0225] A method for modeling the integrated broadband electromagnetic radiation characteristics of an electromechanical system based on cable current and near-field test data of electrical equipment. The technical content is the same as any one of Examples 1-10. Further, the relative error between the test value and the value calculated by this method is as follows:

[0226]

[0227] Among them, i is the serial number of the calculation plane, i = 1, 2,..., Ni, and Ni is the number of calculation planes; j is the number of measurement points in each measurement plane, j = 1, 2,..., Nj, and Nj is the total number of calculation points in the i-th extrapolation plane; t takes three components of x, y, and z. is the j-th calculation point in the i-th extrapolation plane, and the electric field value obtained from the dipole array equivalent model; is the measured / value-simulated electric field value corresponding to this point; Re and Im are the real part and the imaginary part of the electric field respectively.

[0228] Example 11:

[0229] The specific steps of the collaborative modeling of the multi-dipole array combination based on the current test data of the interconnection cable terminals in the electromechanical system and the near-field data of each strong electromagnetic device in the system are as follows, and the method flow chart is as Figure 1 shown:

[0230] (1) Modeling method for the broadband radiation characteristics of strong electromagnetic devices:

[0231] 1) First, obtain the near-field data of each strong electromagnetic device in the electromechanical system at the preset frequency test points within the broadband through near-field measurement. In this paper, s preset frequency points f0, f1,..., f s-1 are taken as examples for discussion, and f0 < f1 <... < f s-1 .

[0232] 2) Secondly, based on the existing near-field data, utilize the global optimization ability of the ADE algorithm to establish an optimal equivalent dipole array model at s frequency points by minimizing the error between the radiation electric field generated by the dipole array and the test electric field, so as to achieve high-precision equivalent modeling of the radiation characteristics of each strong electromagnetic device in the electromechanical system at s frequency points.

[0233] The following are the detailed steps of the ADE algorithm for searching the optimal population of the equivalent dipole array of each strong electromagnetic device in the electromechanical system.

[0234] (a) Parameter and population initialization

[0235] When applying the ADE algorithm to find the optimal equivalent dipole array, it is first necessary to initialize the population and set parameters. Set the maximum number of iterations as MaxGen; initialize the external archive population A as an empty set, and A is used to store the individuals that have successfully participated in mutation; at the same time, the sets SCR and SF of the crossover probability factor and the scaling factor are also initially empty sets; according to the requirements of the optimization problem, set the expectation μCR of the normal distribution, the location parameter μF of the Cauchy distribution, the probability p of the optimal individual in each generation among all individuals, and the control factor c. In addition, set the population size as Ns; set the size of a population as NP, which depends on the number of dipole units in the dipole array; the individual size (the dimension of each individual) is expressed as Dim.

[0236] The initial population is defined as {x i,0 = (x 1,i,0 , x 2,i,0 ,..., x j,i,0 ,..., x Dim,i,0) | i = 1, 2, ..., NP}, specifically set as shown in (1). The expression of an individual in the population includes the position of the dipole and the dipole moment information at each frequency point.

[0237]

[0238] Where Re and Im represent the real and imaginary parts of the complex value respectively. The dimension Dim is related to the number of frequency points required for modeling.

[0239] After that, each individual is randomly generated according to a uniform distribution. Then, at the initial iteration G = 0, the j-th dimension of the i-th individual can be expressed by Equation (2).

[0240]

[0241] (b) Set the fitness function f according to the problem to be solved.

[0242] Next, define the fitness function in the ADE algorithm, which will guide the evolution of the population in the direction of reducing the error, that is, minimizing the gap between the field generated by the dipole array and the tested field, as shown in Equation (3).

[0243]

[0244] Where Re and Im are respectively taking the real and imaginary parts of the electric field.

[0245] The three-dimensional electric dipole array model is composed of several electric dipoles, and the expression of the radiated electric field it generates can be obtained by the superposition theorem and can be expressed by Equation (4).

[0246]

[0247] Among them, r, x i',j' , y i',j' and z i',j' can be expressed by Equation (5).

[0248]

[0249] Among them, K e , f1(r), f2(r) can be expressed by Equation (6).

[0250]

[0251] Among them is the free space propagation constant, μ0 = 4π×10 -7 H / m is the free space magnetic permeability, ε0 = 8.854×10 -12 F / m is the free space permittivity, ω is the angular frequency; is the wave impedance of free space.

[0252] The system of linear equations in Equation (4) is written in the form of a matrix equation as shown in Equation (7).

[0253]

[0254] The coefficient matrix T e can be obtained by rearranging Equation (5).

[0255] and represent the dipole moments Px, P y and P z and the electric field The conversion relationship between them is as follows:

[0256]

[0257] and correspond to the electric dipole moments Px, P y and P z and the electric field The conversion relationship between them is as follows:

[0258]

[0259] and represent the electric dipole moments Px, P y and P z and the electric field The conversion relationship between them is as follows:

[0260]

[0261] where r1 and r2 can be calculated from Equation (11).

[0262]

[0263] When there is a ground, the electric field of the dipole array is generated by both the real equivalent source and the image equivalent source. If the reference ground is located at z = 0 and the electric dipole array is located at z = z i′,j′ , according to the image theory, Equation (8) becomes Equation (12).

[0264]

[0265] Equation (9) becomes Equation (13).

[0266]

[0267] Equation (10) becomes Equation (14).

[0268]

[0269] (c) Calculate the crossover probability factor CRi and the scaling factor Fi for each individual in each generation of the population, and store them in the set SCR and the set SF respectively.

[0270] CRi is generated according to the normal distribution with mean μCR and standard deviation 0.1, and can be represented by Equation (15). Fi follows the Cauchy distribution with location parameter μF and standard deviation 0.1, and can be represented by Equation (16).

[0271] CR i = randni(μ CR , 0.1)(15)F i = randci(μ F , 0.1)(16)

[0272] (d) For the population {x i,0 = (x 1,i,0 , x 2,i,0 ,..., x j,i,0 ,..., x Dim,i,0 ,)|i = 1, 2,..., NP,} obtained by initialization, create a mutant vector according to the mutation strategy "DE / current-to-pbest" in each iteration. The mutant vector v i,G in the G-th iteration can be represented by (17).

[0273]

[0274] where x i,G is the population in the G-th generation. is randomly selected from the individuals in the top 100p% of the fitness values in the current population, p ∈ (0, 1). x r1,G is randomly selected from the current individual, x r2,G is randomly selected from the union of the current population and the archive population A, and they satisfy x r2,G ≠ x r1,G ≠ x i,G .

[0275] (e) To increase the diversity of the population and avoid the population individuals from falling into local optima due to "inbreeding", it is necessary to perform a crossover operation on the mutant individual v i,G vj,i,G and the corresponding parent individual x i,G in each dimension, that is, exchange a part of the solution to obtain a new set of candidate solution vectors u i,G , which can be represented by Equation (18).

[0276]

[0277] In the formula, CRi is the crossover probability factor.

[0278] (f) Perform a selection operation based on the fitness value, that is, select the one with better fitness between x i,G and u i,G as the parent individual x of the next generation for optimization operation. For a minimization problem, the selection mechanism can be represented by Equation (19). j,i,G For a minimization problem, the selection mechanism can be represented by Equation (19).

[0279]

[0280] If the u i,G scheme is successfully selected during the selection process, the corresponding CRi and Fi are respectively stored in the set SCR and the set SF. SCR represents the set of all successful crossover probability factors CRi in the G-th generation population. SF represents the set of all successful mutation factors in the G-th generation population. x i,G is added to the external archive population A. If the size of the external archive population A exceeds the threshold NP, some individuals are randomly deleted from it.

[0281] (g) At the end of each generation loop, the values of the μCR and μF parameters are controlled by adaptive parameters, which can be calculated by Equations (20) and (21).

[0282] μ CR = (1 - c)·μ CR + c·mean A (S CR )(20)

[0283] where c is a control factor, which has strong adaptability to different problem-solving abilities, c ∈ (0, 1), and mean A (S CR ) represents the arithmetic mean of the elements of the set SCR.

[0284] (h) After that, the mutation, crossover, and selection operations are performed in a loop until the fitness function value of the optimal population meets the preset termination iteration criterion or reaches the maximum number of iterations, and the optimal dipole array is output.

[0285] 3) After applying the ADE optimization method to determine the optimal dipole array of each strong electromagnetic device in the electromechanical system at s known preset frequency points, the polynomial coefficients of the broadband dipole parameters are determined by solving a linear equation, and a broadband model of the dipole array is established.

[0286] For the same radiation source, fix the heights and distributions of the dipole arrays at different frequency points to ensure the mutual correlation between the dipole moments. Then, make the dipole moment parameters of each dipole be frequency-dependent functions. Assuming such functions vary continuously with frequency, the dipole moment parameter x in the model 1,i can all be expressed as Taylor expansion polynomials of the free-space phase constant β, as shown in Equation (22).

[0287]

[0288] The key is to solve for the unknown parameters in the polynomial When using the ADE optimization algorithm to search for the optimal solution, it is necessary to know the upper and lower bounds of the optimization parameter space to ensure that the optimization can be performed within a reasonable range. Then, use the dipole parameter values at each frequency to construct the optimization parameter space. Once the dipole parameter values in the optimal dipole array are determined, the polynomial coefficients of the dipole parameters in Equation (22) can be obtained by solving a linear system.

[0289] Taking Re(P x,i ) as an example, β0, …, β i , …, β s-1 are the free-space constants corresponding to s preset frequency points. Then, the coefficients of the polynomial of the frequency phase of Re(P x,i ) are calculated by Equation (23).

[0290]

[0291] Among them, represents the real part value of the electric dipole moment in the x direction corresponding to the i-th dipole in the optimal population at f0, …, f s-1 .

[0292] Similarly, the polynomial coefficients of other dipole parameters can also be obtained in a similar manner to Equation (23). Once the unknown coefficients of the polynomial are obtained, each dipole parameter can be characterized as a frequency-dependent function, and the dipole array at the frequency point to be solved can be obtained based on this function.

[0293] Finally, after obtaining the dipole array at the calculated frequency point, according to the relationship between the dipole array and the radiation field, that is, Equation (7), the broadband radiation characteristics of the strong electromagnetic device can be calculated accurately and effectively.

[0294] (2) Model the broadband radiation characteristics of the interconnection cables between strong electromagnetic devices in the electromechanical system.

[0295] 1) Obtain the terminal current data of the cable ports in the electromechanical system through measurement, as Figure 2 shown.

[0296] 2) Establish an equivalent N-port model of the connector using the scattering parameters of the connectors in the interconnection cable, as Figure 3 shown. To accurately characterize the characteristics of the connector, it is necessary to obtain its scattering parameters.

[0297]

[0298] Among them, S UU , S UV , S VU and S VV are the elements of the scattering parameter matrix of the port network; A UU , B UV , C VU and D VV are the elements of the transmission matrix of the port network. V U and V V are the voltage matrices; I U and I V are the current matrices. The incident wave and the reflected wave of the U port are represented by a U and b U , where a U = diag(a1,…,a U ). The incident wave and the reflected wave of the V port are represented by a V and b V .

[0299] According to Equations (26) and (27), the transmission parameter matrix T C of the connector can be obtained through conversion of the scattering parameters.

[0300]

[0301] In the formula, 1 is the identity matrix. Z U Z U is the impedance matrix of the U port, Z V is the impedance matrix of the V port, are the conjugates of Z U and Z V respectively; g U and g V can be set as the following formula.

[0302]

[0303] In the formula, Z 0,i is the Figure 3 corresponding port impedance shown, which can be obtained by measurement or simulation, is the conjugate of Z 0,i .

[0304] 3) Calculate the per-unit-length parameter matrix and transmission matrix of the cable. For simple cables, use the corresponding formulas for calculation. For complex cables, the distributed parameters can be directly extracted using full-wave simulation software such as CST, and the corresponding MTL equations can be established.

[0305]

[0306] Among them, and are the column vectors of voltage and current respectively, and are the impedance matrix and admittance matrix of the wire harness respectively, which can be expressed by Eqs. (31) and (32).

[0307]

[0308] In the formula, R, L, C, and G are the per-unit-length resistance, inductance, capacitance, and conductance parameters respectively.

[0309] 4) Cascade the transmission parameter matrices of all the curved cables and connectors to obtain the overall transmission parameter matrix, and then an arbitrary interconnect cable cascade model considering various factors can be established.

[0310] ① Transmission parameter matrix of the transmission line

[0311] For Figure 4 the cable network shown, without loss of generality, any cable (including straight and uniform and curved and irregular) can be regarded as a non-uniform cable. The four per-unit-length parameters of the non-uniform cable are unevenly distributed, and it can be divided into a cascade of several very short uniform line elements to be approximately equivalent to a uniform transmission line. The transmission parameter matrix of the cascaded transmission line can be obtained by the product of the transmission parameter matrices of each section of the cable. If a non-uniform cable is decomposed into m sections, and each line element is Δz, the transmission matrix of the whole cable can be calculated by Eq. (33).

[0312]

[0313] In the formula, is the transmission parameter matrix of the oth uniform cable sub-section, which can be calculated by the following formula.

[0314]

[0315] In the formula, is the similarity diagonal matrix of the oth uniform cable sub-section, is the admittance matrix of the cable section, is the propagation constant of the oth section of the uniform cable sub-section.

[0316] ② Equivalent transmission parameter matrix of the parallel branch cable

[0317] Such asFigure 4 As shown in the figure, the interconnected cable network consists of a main cable and numerous branch cables. Figure 4 The branch k shown in the figure can be equivalent to a multi-port model, as Figure 5 shown. First, calculate the transmission parameter matrix of the branch cable according to Eqs. (33) - (35).

[0318] Then, the parallel branch transmission matrix can be calculated by Eq. (36).

[0319]

[0320] In the formula, 1 is the identity matrix; is the equivalent input impedance of the branch line. The equivalent input impedance of this branch line can be calculated based on the transmission parameter matrix of the branch cable, as shown in Eq. (37).

[0321]

[0322] Among them, is the ratio of the input voltage to the input current of the branch line. and are the input voltage and input current of the branch line respectively; is the terminal voltage of the branch cable; is the terminating load of the branch cable, and are the elements of the transmission parameter matrix of the branch cable.

[0323] ③ Transmission parameter matrix of the cascaded network

[0324] Multiply the T-parameter matrices of the components of the cascaded network to obtain the entire transmission matrix of the cascaded network. Figure 4 The T-parameter matrix of the cable network shown can be expressed as Eq. (38).

[0325]

[0326] Among them, is the transmission parameter matrix of the connector, is the transmission parameter matrix of the cable of the kth duct, is the equivalent transmission parameter matrix of all branches connected to node k. The middle multiplication part is the product of the transmission parameter matrix representing the port itself and the equivalent transmission parameter matrix of all branches connected to this node.

[0327] 5) Solve the cable MTL equation by combining the boundary constraint conditions to obtain the current distribution on the interconnected cables in the electromechanical system, and then calculate the electric field radiation of the cable network through the dipole array theory.

[0328] ① Solve the cable current

[0329] According to the multi-conductor transmission line theory, using the measured terminal current voltage the current at any point on the transmission line can be obtained. The voltage of the i-th section on the transmission line and current can be calculated by Equation (39).

[0330]

[0331] ② Calculate the electric field radiation of the cable network.

[0332] When the shape of the cable in space is arbitrarily curved, the current on the cable does not propagate uniformly along its axis direction, but propagates in any direction in three-dimensional space. Therefore, the current with any direction needs to be decomposed into x, y, and z components. Then, the dipole array theory is used to calculate the electric field radiated by each component current into space, and finally, the electric field contributions of each section are superimposed.

[0333] If the current at any point on the cable is then its components in the three coordinate axes of x, y, and z are respectively and It can be calculated according to the spatial angles α x , α y and α z between the cable and the x, y, and z axes, and can be expressed by Equation (40) and Equation (41).

[0334]

[0335] After calculating the surface current distribution of the cable network, each current-carrying cable section is equivalent to an electric dipole, and the dipole array theory is applied to calculate its radiation field.

[0336] According to the dipole array theory, the radiation electric field values of all current elements discrete on the transmission line are superimposed in each coordinate direction respectively, and the radiation electric field generated by the cable can be obtained. The electromagnetic radiation of the real cable section at any electric field observation point (x p , y p , z p ) can be expressed by Equation (42).

[0337]

[0338] Among them, (x i , y i , z i ) is the position of the i-th current-carrying cable section, and r i is the distance between the i-th current-carrying cable section and the electric field observation point; and is the current of the x, y, and z components of the i-th current-carrying cable segment; Δx i , Δy i and Δz i is the length of the i-th current-carrying segment, and the product of the current of the dipole and its size is the electric dipole moment. and are the electric fields in the x, y, and z directions generated by the i-th current-carrying segment respectively. ε is the external environmental permittivity, ω is the current angular frequency, β is the free-space wave number, and Nz is the number of current-carrying segments. Among them, θ zi and are the polar angle and azimuth angle of the i-th z-direction dipole current-carrying segment in the spherical coordinate system respectively, and can be expressed by Equation (43).

[0339]

[0340] θ yi and are the polar angle and azimuth angle of the i-th y-direction dipole current-carrying segment in the spherical coordinate system respectively, and can be expressed by Equation (44).

[0341]

[0342] θ xi and are the polar angle and azimuth angle of the i-th x-direction dipole current-carrying segment in the spherical coordinate system respectively, and can be expressed by Equation (45).

[0343]

[0344] It should be noted that when the ground is used as the reference conductor, the electromagnetic field will be reflected on the ground. Assuming that the ground is of infinite size, the method of images can be introduced to deal with the reflection effect. It replaces the plane with the image of the current-carrying conductor and calculates the result of the superimposed field generated by the actual conductor and its image, and the field in any direction above the image plane can be calculated, as shown in Figure 6 .

[0345] The total radiation electric field generated by the cable network can be expressed by Equation (46).

[0346]

[0347] In the formula, and are the total radiation electric fields generated by the real current segment and the image current segment on the cable network respectively, and are the image and real electric fields generated by the support end respectively. According to the same process above, they can be calculated using the dipole array theory.

[0348] (3) Modeling Method for Wide - Band Radiation Characteristics of Electromechanical Systems

[0349] Finally, the electric field generated by the equivalent dipole array of the cable and the electric field generated by the equivalent dipole array of the device are vectorially superposed to obtain the radiation electric field of the electromechanical system which can be expressed by Equation (47).

[0350]

[0351] Define the relative error between the calculated radiation electric field and the measured electric field as Equation (48).

[0352]

[0353] where i is the serial number of the calculation plane, i = 1, 2,..., Ni, and Ni is the number of calculation planes; j is the serial number of the measurement points in each measurement plane, j = 1, 2,..., Nj, and Nj is the total number of calculation points in the i - th extrapolation plane; t takes three components of x, y, and z. is the j - th calculation point in the i - th extrapolation plane, and the electric field value is obtained from the equivalent model of the dipole array is the measured / numerically simulated electric field value corresponding to this point. Re and Im are respectively taking the real part and the imaginary part of the electric field.

[0354] Example 12:

[0355] Verification of an integrated wide - band electromagnetic radiation characteristics modeling method for electromechanical systems based on cable current and near - field test data of electrical equipment is as follows:

[0356] The specific steps of the integrated wide - band electromagnetic radiation interference characteristics modeling method for electromechanical systems are as follows: The first step is to establish an equivalent dipole array model of a strong electromagnetic device. First, it is necessary to obtain the near - field data near the strong electromagnetic device at a finite number of frequency points. Then, the ADE optimization algorithm is used to determine the optimal equivalent dipole array representing the radiation characteristics of the strong electromagnetic device. Finally, combined with the optimal dipole population, the polynomial coefficients of each dipole parameter can be obtained by solving a series of linear equations. Once the polynomial coefficients are determined, the equivalent dipole array of the strong electromagnetic device at different frequencies can be calculated, and then the radiation characteristics of the strong electromagnetic device at different frequencies can be obtained In the second step, the terminal current data of the interconnection cables in the electromechanical system are measured, the cable current distribution is solved by combining the boundary equations, and then the electric field of the cable at the same space and the same frequency is calculated using the dipole theory In the third step, the two parts of the electric fields are vectorially summed to obtain the total electric field

[0357] Taking the modeling and analysis of an electromechanical system composed of interconnected cables and a strong electromagnetic cabinet as an example, the specific implementation manner of this invention patent is demonstrated. The calculation model is as Figure 7 shown.

[0358] The size of the strong electromagnetic device is set to: 0.70m × 0.60m × 0.40m. There are many small holes for ventilation, cooling and maintenance on both sides and the upper side of the cabinet. There is a small window on the right side of the chassis, and a broadband Archimedean spiral antenna is placed behind the small window to simulate the leaked radiation electric field in the strong electromagnetic cabinet. The interconnected devices are connected by a 0.5m long cable. The height z of the near-field measurement plane is 0.25m, the size of the measurement plane is 1m × 1m, and the measurement interval is 40mm, as Figure 8 shown. The size of the calculation plane is 1m × 1m, and the height is z = 0.6m. The data of the near-field scanning plane at ten frequency points are tested for modeling. The frequency points are 30MHz, 82MHz, 135MHz, 188MHz, 242MHz, 293MHz, 346MHz, 398MHz, 451MHz and 504MHz. 64 electric dipoles are used to establish the broadband radiation characteristic model of the electromechanical system. The ADE algorithm parameters are set as: p = 0.2, μCR = 0.5, μF = 0.5, c = 0.2. In ADE, when the optimal fitness value of the population is less than 0.10, the iteration process terminates, and the optimal population is obtained at this time. Subsequently, combining the dipole parameters of the optimal population, the matrix equation is solved to obtain all polynomial coefficients, and the relationship between the dipole parameters and the frequency is characterized, so as to obtain the dipole array at different frequencies. Taking a dipole in an optimal population as an example below, the relationship between the dipole parameters and the frequency is given, as Figure 9 shown. To verify the effect of the method of this invention in predicting the electric field in the entire wide frequency band, in the range of 30MHz to 504MHz, the radiation electric field at a detection point (0mm, 0mm, 600mm) is calculated every 1MHz, as Figure 10 shown.

[0359] The size of the strong electromagnetic device is set to: 0.70m × 0.60m × 0.40m. There are many small holes for ventilation, cooling and maintenance on both sides and the upper side of the cabinet. There is a small window on the right side of the chassis, and a broadband Archimedean spiral antenna is placed behind the small window to simulate the leaked radiation electric field in the strong electromagnetic cabinet. The interconnected devices are connected by a 0.5m long cable. The height z of the near-field measurement plane is 0.25m, the size of the measurement plane is 1m × 1m, and the measurement interval is 40mm, as Figure 8As shown. The calculation plane has dimensions of 1m×1m and a height of z = 0.6m. The data of the near-field scanning plane at ten frequency points are tested for modeling. The frequency points are 30MHz, 82MHz, 135MHz, 188MHz, 242MHz, 293MHz, 346MHz, 398MHz, 451MHz, and 504MHz. A broadband radiation characteristic model of the electromechanical system is established using 64 electric dipoles. The ADE algorithm parameters are set as: p = 0.2, μCR = 0.5, μF = 0.5, c = 0.2. In ADE, when the optimal fitness value of the population is less than 0.10, the iterative process terminates, and the optimal population is obtained at this time. Subsequently, combining the dipole parameters of the optimal population, the matrix equation is solved to obtain all polynomial coefficients, so that the relationship between the dipole parameters and the frequency is characterized, and the dipole array at different frequencies is obtained. Taking a dipole in an optimal population as an example, the relationship between the dipole parameters and the frequency is given as Figure 9 shown. To verify the effect of the method of the present invention in predicting the electric field in the entire wide frequency band, in the range of 30MHz to 504MHz, the radiated electric field at a detection point (0mm, 0mm, 600mm) is calculated every 1MHz, as Figure 10 shown.

[0360] Table 1 Relative error of electric field of different modeling methods

[0361]

Claims

1. An integrated electromechanical system broadband electromagnetic radiation characteristic modeling method based on cable current and electrical equipment near-field test data, characterized in that It includes the following steps: 1) Model the wide-band radiation characteristics of each strong electromagnetic device in the electromechanical system to obtain the radiation electric field generated by the strong electromagnetic device 2) Model the wide-band radiation characteristics of the interconnection cables between the strong electromagnetic devices in the electromechanical system to obtain the radiated electric field generated by the cables 3) The radiated electric field generated by strong electromagnetic devices and the radiated electric field generated by cables are vectorially superimposed to obtain the radiated electric field of the electromechanical system 2. A method for modeling the integrated broadband electromagnetic radiation characteristics of a mechatronic system based on cable current and near-field test data of electrical equipment, characterized in that, In step 1), the steps of modeling the wide-band radiation characteristics of each strong electromagnetic device in the electromechanical system include: 1.1) Obtain the near-field data of each strong electromagnetic device in the electromechanical system at the preset frequency test points within the broadband through the near-field measurement method; the preset frequency test points are denoted as f0, f1, …, f s-1 , and f0 < f1 < … < f s-1 ; 1.2) Using the ADE algorithm to minimize the error between the radiation electric field generated by the dipole array and the test electric field, so as to establish an optimal equivalent dipole array at different preset frequency test points; 1.3) Solving the optimal equivalent dipole array, determining the polynomial coefficients of the broadband dipole parameters, and thus establishing a broadband model of the wide-band radiation characteristics of each strong electromagnetic device.

3. A method for modeling the integrated broadband electromagnetic radiation characteristics of an electromechanical system based on cable current and near-field test data of electrical equipment, characterized in that, In step 1.2), the steps of establishing an optimal equivalent dipole array at different preset frequency test points include: 1.2.1) Parameter and population initialization; 1.2.2) Setting the fitness function F, that is: Where s is the number of frequency points, w is the w-th frequency point calculated; N is the total number of points on the near-field plane at each frequency; t takes three components of x, y, and z. is the measured value of the t-component electric field of the q-th calculation point at the w-th frequency point; is the calculated value of the t-component electric field of the q-th calculation point at the w-th frequency point; Re and Im are respectively taking the real part and the imaginary part of the electric field; 1.2.3) Calculating the crossover probability factor CRi and the scaling factor Fi of each individual in each generation of the population, and storing them in the crossover probability factor set SCR and the scaling factor set SF respectively; Crossover probability factor CR i and scaling factor F i are as follows: CR i = randni(μ CR , 0.1)(2) F i = randci(μ F , 0.1)(3) 1.2.4) Mutating the population individuals to obtain the mutated individuals; The mutated individual v i,G As shown below: where x i,G is the G-th generation population. is randomly selected from the individuals with the top 100p% of the fitness values in the current population, where p ∈ (0, 1). x r1,G is randomly selected from the current individuals, x r2,G is randomly selected from the union of the current population and the archive population A; x r2,G ≠ x r1,G ≠ x i,G ; 1.2.5) In each dimension, for the mutated individual v i,G and the corresponding parent individual x i,G perform a crossover operation to obtain a new candidate solution individual u j,i,G , that is: where CR i is the crossover probability factor. 1.2.6) Select the individual with a better fitness value between x i,G and u i,G as the parental individual x j,i,G for the next generation, i.e.: 1.2.7) Adopt an adaptive parameter update for the expected value μ of the normal distribution CR , the location parameter μ of the Cauchy distribution F , and return to step 1.2.3) until the fitness function value of the optimal population meets the preset iteration termination criterion or reaches the maximum number of iterations, and output the optimal dipole array. Updated expected value μ of the normal distribution CR , location parameter μ of the Cauchy distribution F Are as follows: μ CR = (1 - c)·μ CR + c·mean A (S CR )(7) Among them, c is a control factor, c ∈ (0, 1), mean A (S CR ) represents the arithmetic mean of the elements of the set SCR.

4. A method for modeling the integrated broadband electromagnetic radiation characteristics of an electromechanical system based on cable current and near-field test data of electrical equipment, characterized in that, In step 1.2.1), the steps of parameter and population initialization are: Setting the maximum number of iterations as MaxGen; Initializing the external archive population A as an empty set; Initializing the crossover probability factor set SCR and the scaling factor set SF as empty sets; Set the expectation μ of the normal distribution CR , the location parameter μ of the Cauchy distribution F , the probability p of the optimal individual in each generation among all individuals, and the control factor c; Setting the population size as Ns, the scale of one population as NP, and the individual scale as Dim; Define the initial population as {x i,0 =(x 1,i,0 , x 2,i,0 ,..., x j,i,0 ,..., x Dim,i,0 ) | i = 1, 2,..., NP}; Among them, the individuals in the population are as follows: where i refers to the serial number of the electric dipole, x i , y i and z i describe the position of the i-th electric dipole; and are the electric dipole moments in the three directions of the i-th electric dipole at the frequency f0, respectively; are the electric dipole moments in the three directions of the i-th electric dipole at the frequency f s-1 respectively; Re and Im represent the real and imaginary parts of the complex value, respectively. At the initial iteration G = 0, the j-th dimension x of the i-th individual is as follows: j,i,0 as follows: wherein, and are the maximum and minimum boundaries that an individual can take in the j-th dimension, and rand(0,1) is a random number uniformly distributed between 0 and 1.

5. A method for modeling the integrated broadband electromagnetic radiation characteristics of a mechatronic system based on cable current and near-field test data of electrical equipment, characterized in that, The optimal equivalent dipole array is as follows: where, P i',j',x , P i',j',y and P i',j',z are the electric dipole moment components in the x, y, and z directions of the j'-th electric dipole in the i'-th dipole plane, respectively, where i = 1, 2, ..., Ni, and Ni is the number of dipole planes. and are the electric fields in the x, x, and z directions at the j-th measurement point on the i-th near-field plane, respectively, where j = 1, 2, ..., Nj, and Nj is the number of measurement points on each scanning plane; Among them, the distance r, coordinates x i',j' , y i',j' and z i',j' are as follows: where x i',j' , y i',j' and z i',j' respectively represent the x, y, and z coordinates of the j'-th electric dipole in the i'-th dipole plane; x i,j , y i,j and z i,j respectively represent the x, y, and z coordinates of the j-th measurement point in the i-th near-field plane; r represents the distance between the measurement point and the dipole. where K e , f1(r), and f2(r) are as follows: Among them, is the free space propagation constant, μ0 is the magnetic permeability of free space, ε0 is the permittivity of free space, and ω is the angular frequency; is the wave impedance of free space; The matrix form of the optimal equivalent dipole array is as follows: where Px, P y and P z are the electric dipole moments of the dipoles in the electric dipole array in each direction respectively. and are the electric field values in the x, y, and z directions of the measurement point respectively; T e is the coefficient matrix; In the absence of a ground plane, the conversion relationships between the dipole moments Px, P y and P z and the electric field are as follows: and are as follows: When there is a ground, the dipole moments Px, P y and P z and the electric field The conversion relationship between and is as follows: In the absence of a ground plane, the conversion relationships between the electric dipole moments Px, P y and P z and the electric field are as follows: and are as follows: When there is a ground, the electric dipole moments Px, P y and P z and the electric field The conversion relationship between and is as follows: In the absence of a ground plane, the conversion relationships between the electric dipole moments Px, P y and P z and the electric field are as follows: and are as follows: When there is a ground, the electric dipole moments Px, P y and P z and the electric field The conversion relationship between and is as follows: Among them, r1 and r2 are as follows:

6. A method for modeling the integrated broadband electromagnetic radiation characteristics of an electromechanical system based on cable current and near-field test data of electrical equipment, characterized in that, In step 2), the steps of modeling the wide-band radiation characteristics of the interconnection cables between each strong electromagnetic device in the electromechanical system include: 2.1) Measuring the terminal current data of the cable ports in the electromechanical system; 2.2) Using the scattering parameter matrix of the connectors in the interconnection cables to establish an equivalent N-port model of the connectors; 2.3) Calculating the per-unit-length parameter matrix and the transmission matrix of the cable, and establishing the cable MTL equation, that is: wherein, R, L, C, and G are the resistance, inductance, capacitance, and conductance parameters per unit length, respectively; and are the column vectors of voltage and current, respectively; and are the impedance matrix and admittance matrix of the wire harness, respectively; 2.4) Obtaining the transmission parameter matrix of the bent cable, and cascading the transmission parameter matrices of the bent cable and the connector, so as to establish an arbitrary interconnection cable cascade model; 2.5) Combining the cable port cable boundary constraint conditions and the arbitrary interconnection cable cascade model, solving the cable MTL equation, obtaining the current distribution on the interconnection cables in the electromechanical system, and using the dipole array theory to calculate the electric field radiation of the cable network, so as to model the wide-band radiation characteristics of the interconnection cables between each strong electromagnetic device in the electromechanical system.

7. A method for modeling the integrated broadband electromagnetic radiation characteristics of a mechatronic system based on cable current and near-field test data of electrical equipment, characterized in that, In step 2.2), the scattering parameter matrix T of the connector C is as follows: where S UU , S UV , S VU and S VV are elements of the scattering parameter matrix of the port network; A UU , B UV , C VU and D VV are elements of the transmission matrix of the port network. V U and V V are voltage matrices; I U and I V are current matrices; a U and b U represent the incident wave and the reflected wave of the U port; a U = diag(a1,…,a U ); a V and b V represent the incident wave and the reflected wave of the V port; 1 is the identity matrix. Z U Z U is the impedance matrix of the U port, Z V is the impedance matrix of the V port, are the conjugates of Z U and Z V respectively; Z 0,i is the port impedance; is the conjugate of Z 0,i ; J, G are intermediate matrices; g U , g V are parameter vectors; g 0_i is an intermediate parameter.

8. A method for modeling the integrated broadband electromagnetic radiation characteristics of an electromechanical system based on cable current and near-field test data of electrical equipment, characterized in that, In step 2.4), establishing an arbitrary interconnection cable cascade model 2.4.1) Divide the bent cable into multiple uniform cable sub-segments to construct the transmission matrix of the bent cable That is: Among them, the transmission parameter matrix of the o-th uniform cable sub-segment is as follows: wherein, is the similarity diagonal matrix of the o-th uniform cable sub-segment, is the admittance matrix of the cable segment, is the propagation constant of the o-th uniform cable sub-segment; and are the elements of the transmission parameter matrix; 2.4.2) Cascading the transmission parameter matrices of the bent cable and the connector to obtain: Among them, is the ratio of the input voltage to the input current of the branch line. and are the input voltage and input current of the branch line respectively; is the terminal voltage of the branch cable; is the terminating load of the branch cable, and are the elements of the transmission parameter matrix of the branch cable; 1 is the identity matrix; is the equivalent input impedance of the branch line; is the cascaded transmission parameter matrix; 2.4.3) Establish an arbitrary interconnect cable cascading model That is: Among them, is the transmission parameter matrix of the connector, is the transmission parameter matrix of the cable of the k-th duct, is the equivalent transmission parameter matrix of all branches connected to node k.

9. A method for modeling the integrated broadband electromagnetic radiation characteristics of an electromechanical system based on cable current and near-field test data of electrical equipment, characterized in that, In step 2.5), the steps of calculating the electric field radiation of the cable network include: 2.5.1) Solving the cable current, that is: In the formula, is the voltage; is the current; 2.5.2) Calculating the surface current distribution of the cable network, that is: where α x , α y , α z are component angles; 2.5.3) Equivalent each current-carrying segment of the cable to an electric dipole, and applying the dipole array theory to calculate the radiation field to obtain: where (x i , y i , z i ) is the position of the i-th current-carrying segment of the cable, and r i is the distance between the i-th current-carrying segment of the cable and the electric field observation point; and are the currents in the x, y, and z components of the i-th current-carrying segment of the cable; Δx i , Δy i and Δz i are the lengths of the i-th current-carrying segment. The product of the current of the dipole and its size is the electric dipole moment. and are the electric fields in the x, y, and z directions generated by the i-th current-carrying segment, respectively. ε is the external environmental permittivity, ω is the current angular frequency, β is the free space wavenumber, and Nz is the number of current-carrying segments; wherein, the polar angle θ of the i-th z-direction dipole current-carrying segment in the spherical coordinate system zi and the azimuth angle are as follows: The polar angle θ of the i-th current-carrying segment of the y-direction dipole in the spherical coordinate system yi and the azimuth angle are as follows: The polar angle θ of the i-th x-direction dipole current-carrying segment in the spherical coordinate system xi and the azimuth angle are as follows: 2.5.4) Calculate the total radiated electric field generated by the cable network That is: Wherein, and are the total radiation electric fields generated by the real current segment and the image current segment on the cable network respectively, and are the image and real electric fields generated by the support end respectively.

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