A method and system for evaluating pulsed electromagnetic fields

Abstract

The present application relates to a method and system for evaluating pulsed electromagnetic field, comprising: for the road field generating device with conical or cylindrical structure, using uniformity index to evaluate pulsed electromagnetic field; or, evaluating the full waveform of pulsed electromagnetic field and / or the attribute of main pulse and / or stray pulse therein. The present application makes pulsed electromagnetic field have quantitative standard by evaluating the full waveform of pulsed electromagnetic field and / or the attribute of main pulse and / or stray pulse therein. For the evaluation of uniformity index, the quantitative relationship between the acceptable size of measured object and the space of pulsed electromagnetic field and its field uniformity is established, which enhances the reliability, accuracy and consistency of the experiment.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic field technology, specifically relating to a method and system for evaluating pulsed electromagnetic fields. Background Technology

[0002] Pulsed electromagnetic fields are widespread in nature and industry, and are an important component of electromagnetic interference. Specifically, in electromagnetic effect testing, to confirm whether electromechanical and electronic equipment is subjected to various pulsed electromagnetic fields, specialized devices are needed to simulate and reproduce these fields. The basic method is to first generate a pulse waveform in a conductive circuit, and then convert this pulse waveform into an electromagnetic field through appropriate conversion processing. During this conversion process, the generated pulse waveform may be distorted due to various reasons. Therefore, it is necessary to establish indicators for evaluating or assessing pulsed electromagnetic fields. However, existing evaluation or assessment methods define the quality of pulsed electromagnetic fields rather indirectly, such as directly using port voltage waveforms or pulse electric field peak values. These existing methods lead to subjective and biased evaluation results that cannot accurately reflect the performance of pulsed electromagnetic fields. Therefore, it is necessary to propose a method and system for evaluating pulsed electromagnetic fields. Summary of the Invention

[0003] In order to overcome the above-mentioned problems in the prior art, the present invention provides a method and system for evaluating pulsed electromagnetic fields, which solves the above-mentioned problems in the prior art.

[0004] A method for evaluating pulsed electromagnetic fields includes:

[0005] S1. For road field generation devices with conical or cylindrical structures, uniformity index is used to evaluate pulsed electromagnetic fields;

[0006] Alternatively, S2. Evaluate the properties of the full waveform of the pulsed electromagnetic field and / or the main pulse and / or stray pulses therein.

[0007] In addition to the aspects and any possible implementations described above, an implementation is further provided, wherein S1 specifically includes:

[0008] S11. The feed point of the road field generation device is the origin of the coordinate system, and a cylindrical coordinate system or a spherical coordinate system is constructed with the direction of electromagnetic wave propagation as the radial direction.

[0009] S12. Obtain the theoretical value of the electric field waveform of the road field conversion device in cylindrical or spherical coordinate system;

[0010] S13. Obtain the field uniformity error of the object being measured in the electric field;

[0011] S14. Obtain the uniformity index based on the theoretical value of the electric field waveform and the field uniformity error.

[0012] In addition to the aspects described above and any possible implementation, a further implementation is provided, wherein S2 specifically includes: setting A' as the time coordinate of the peak value of the main pulse A, and B' as the peak time coordinate of the earliest appearing stray pulse B; using the time difference from A' to B' to characterize the time window of the pulsed electromagnetic field, with the stray pulse amplitude corresponding to B' being E1 and the main pulse amplitude corresponding to A' being E0, then using the ratio of the earliest stray peak amplitude of the electric field to K p To evaluate pulsed electromagnetic fields, the expression is as follows:

[0013] In addition to the aspects and any possible implementations described above, a further implementation is provided, wherein S2 specifically includes: setting t1 as the start time of the main pulse A waveform, t2 as the end time of the main pulse A waveform, t3 as the end time of the stray pulse B waveform, and the electric field power as E(t), where t is time, then the stray power ratio of the electric field waveform R... ps To evaluate pulsed electromagnetic fields, the expression is as follows:

[0014]

[0015] In addition to the aspects and any possible implementations described above, a further implementation is provided, wherein S2 specifically includes: setting the ideal non-reflective port voltage of the electric field to U(t) and the power to E(t), then using the full waveform quality R of the electric field. EU To evaluate pulsed electromagnetic fields, the expression is as follows:

[0016] τ delay.

[0017] As described above and in any possible implementation, a further implementation is provided, wherein S2 specifically includes: setting the main pulse waveform of the electric field to E main (t), power is E f (t), then the quality of the electric field main pulse waveform R EfU To evaluate pulsed electromagnetic fields, the expression is as follows:

[0018]

[0019] As described above regarding the aspects and any possible implementations, a further implementation is provided, wherein the R EfU and R EU The values ​​are all less than 1.

[0020] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the road-field conversion device includes a mirrored monocone, a coaxial cone, or an antenna.

[0021] The present invention also provides a system for evaluating pulsed electromagnetic fields, the system comprising:

[0022] Memory, which stores executable instructions;

[0023] A processor that executes the executable instructions in the memory to implement the method.

[0024] Beneficial effects of the present invention

[0025] This invention provides a method for evaluating pulsed electromagnetic fields. For path field generation devices with conical or cylindrical structures, the method uses a uniformity index to evaluate the pulsed electromagnetic field; alternatively, it evaluates the properties of the full waveform and / or the dominant pulse and / or stray pulses within the pulsed electromagnetic field. This invention uses mathematical modeling to assess the uniformity index of the spatial distribution of the electric field generated by path field conversion devices such as mirrored single cones, coaxial cones, and antennas. By evaluating the full waveform and / or the properties of the dominant pulse and / or stray pulses within the pulsed electromagnetic field, this invention provides a quantitative standard for pulsed electromagnetic fields. Furthermore, the evaluation of the uniformity index establishes a quantitative relationship between acceptable test object size and the space and uniformity of the pulsed electromagnetic field, all of which enhance the reliability, accuracy, and consistency of the experiments. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the main pulse and stray pulse in the electric field waveform of the present invention;

[0027] Figure 2 This is a time-based schematic diagram of the main pulse and stray pulse in the electric field waveform of the present invention.

[0028] Figure 3 This is a schematic diagram of the cylindrical coordinate system of the present invention. Figure 1 ;

[0029] Figure 4 This is a schematic diagram of the cylindrical coordinate system of the present invention. Figure 2 ;

[0030] Figure 5 This is a schematic diagram of the time window in the electric field waveform of the present invention;

[0031] Figure 6 This is a schematic diagram of the mirror-like single-cone pulse electromagnetic field of the present invention;

[0032] Figure 7 This is a schematic diagram of the simulation results of the mirror single-cone pulse electromagnetic field waveform of the present invention. Figure 1 ;

[0033] Figure 8 This is a schematic diagram of the simulation results of the mirror single-cone pulse electromagnetic field waveform of the present invention. Figure 2 ;

[0034] Figure 9 This is a schematic diagram of the simulation results of the mirror single-cone pulse electromagnetic field waveform of the present invention. Figure 3 ;

[0035] Figure 10 This is a schematic diagram of the electric field waveform time window of a 2m long mirror-shaped single cone according to the present invention.

[0036] Figure 11 This is a schematic diagram showing the peak amplitude ratio of stray electric field of a 2m long mirror-faced single cone according to the present invention.

[0037] Figure 12 This is a schematic diagram of the full waveform of the electric field at different positions of the 2m long mirror-shaped single cone of the present invention.

[0038] Figure 13 The diagram shows the corresponding cylindrical coordinate system ρ for analysis based on position points taken on two lines with pitch angles θ = 68.5° and 85°. Detailed Implementation

[0039] To better understand the technical solution of this invention, the content of this invention includes, but is not limited to, the specific embodiments described below. Similar technologies and methods should be considered within the scope of protection of this invention. To make the technical problems to be solved, the technical solutions, and advantages of this invention clearer, a detailed description will be provided below in conjunction with the accompanying drawings and specific embodiments.

[0040] It should be understood that the embodiments described in this invention are merely some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0041] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0042] This invention provides a method for evaluating pulsed electromagnetic fields, comprising:

[0043] S1. For road field generation devices with conical or cylindrical structures, uniformity index is used to evaluate pulsed electromagnetic fields;

[0044] Alternatively, S2. Evaluate the properties of the full waveform of the pulsed electromagnetic field and / or the main pulse and / or stray pulses therein, wherein S1 and S2 have no order.

[0045] Furthermore, S1 specifically includes: S11. The feed point of the road field generation device is the origin of the coordinate system, and a cylindrical coordinate system or a spherical coordinate system is constructed with the direction of electromagnetic wave propagation as the radial direction;

[0046] S12. Obtain the theoretical value of the electric field waveform of the road field conversion device in cylindrical or spherical coordinate system;

[0047] S13. Obtain the field uniformity error of the object being measured in the electric field;

[0048] S14. Obtain the uniformity index based on the theoretical value of the electric field waveform and the field uniformity error.

[0049] Specifically, this method is suitable for road field conversion devices with conical or cylindrical structures, including mirrored single cones, coaxial cones, or antennas. A cylindrical or spherical coordinate system is constructed with the feed point of the device as the origin and the electromagnetic wave propagation direction as the radius. Assume ρ is the radius coordinate in the coordinate system defined by the road field conversion device, with a value of 1-10 cm. U(t) is the voltage waveform of the excitation signal, which can be a continuous wave or a pulse waveform, etc. t is time, and E... c (t) is the theoretically calculated value of the electric field waveform obtained by excitation, and then the relationship is as shown in expression (1), where G E It is a constant related to the directionality of the field conversion device and is known in advance. Meanwhile, it is assumed that Δρ is the dimension of the object under test (e.g., an electronic device whose electromagnetic field adaptability needs to be tested) in the radial dimension of the coordinate system, and the field uniformity error ΔE at this dimension is evaluated. c When calculating, use expression (2). The advantage of this method is that it can evaluate the uniformity index of the electric field spatial distribution generated by road field conversion devices such as mirror cones, coaxial cones and antennas through mathematical modeling.

[0050]

[0051]

[0052] Therefore, the obtained uniformity index F E Calculated from expression (3):

[0053]

[0054] Therefore, the beneficial effect of this method is that the uniformity index of the electric field spatial distribution generated by the path field conversion device such as the mirror single cone, coaxial cone or antenna can be evaluated by the above mathematical modeling method, and the uniformity index can be used to evaluate the pulse electromagnetic field.

[0055] S2 specifically includes the time window W of the electric field waveform. tCalculations are performed on stray peak amplitude ratio, waveform stray power ratio, electric field stray peak time interval and electric field stray peak amplitude ratio, electric field overall waveform quality and / or electric field main pulse waveform quality. These methods can be used together or individually to evaluate pulsed electromagnetic fields. Each method is described below.

[0056] Optionally, the time delay from pulse peak position B' to A' is equal to the electric field waveform time window W. t This method is used as an evaluation index to assess pulsed electromagnetic fields. It is suitable for all pulsed electromagnetic field waveforms. Assuming the pulse waveform output by the circuit is an independent single pulse, stray pulses may be generated after the energy is converted from the circuit to the electromagnetic field. These stray pulses are derived from imperfect circuit-field conversion. The time delay of the stray pulse relative to the main pulse is the time window during which the main pulse can transmit without distortion. Assuming A is the time coordinate of the start of the main pulse and B is the time coordinate of the start of the first stray pulse, the time delay of the stray pulse can be represented by B→A, which is the maximum possible time width under the condition of no aliasing with the reflected pulse, i.e., the "time window". However, in actual detection algorithms, the start times A and B of the main pulse are difficult to detect. A' represents the time coordinate of the main pulse peak, and B' represents the time coordinate of the earliest appearing stray pulse peak. The time delays B'→A' and B→A differ slightly in some cases, but the difference is very small. Therefore, the pulse peak position delay B'→A' is used instead, and the time difference from A' to B' is used to characterize the time window of the pulsed electromagnetic field. Another advantage of this method is that it can still detect delays even in cases of slight pulse aliasing, as long as the aliasing has not reached the peak value. Figure 1 As shown. Therefore, in the pulsed electric field required for testing, the time delay of the stray pulse relative to the main pulse is the time window during which the main pulse can transmit without distortion, and the electric field waveform time window W. t The bigger the better.

[0057] Alternatively, the ratio of the earliest stray peak amplitude of the electric field can also be used as an evaluation metric. Similarly, as... Figure 1 As shown, the time difference from A' to B' is used to characterize the time window of the pulsed electromagnetic field. The earliest stray pulse amplitude E1 corresponds to the peak value of the first stray pulse B', and the amplitude ratio of the stray pulse to the main pulse A' is E0. Then, the amplitude ratio Kp of the earliest stray peak of the electric field is calculated by expression (4):

[0058] In a pulsed electric field, the earliest stray peak amplitude is greater than K. p The smaller the better.

[0059] Alternatively, the stray power ratio of the electric field waveform can also be used as an evaluation index, such as... Figure 2As shown, t1 is the start time of the main pulse, t2 is the end time of the main pulse A, and t3 is the end time of the stray pulse B waveform. The stray power ratio R of the electric field waveform is... ps Obtained from expression (5):

[0060] E(t) represents the full waveform pulse, which includes the main pulse and its corresponding stray pulses.

[0061] Optionally, the peak time interval and peak amplitude ratio of the stray electric field can also be considered. In some cases, the earliest stray pulse is not the one with the largest amplitude. Therefore, by traversing the entire pulse, the stray pulse with the largest peak amplitude, E2, is detected. The relative time delay between this stray electric field peak E2 and the main pulse peak E0 is the index stray electric field peak time interval. This interval reflects the arrival time of the largest undesirable stray electric field, and the larger this time, the better. At the same time, the amplitude ratio of the stray electric field peak to the main pulse peak is the stray electric field peak amplitude ratio K. m :

[0062]

[0063] The earliest stray peak amplitude in the electric field is greater than K m The smaller the better, and the larger the time interval between stray electric field peaks, the better.

[0064] Alternatively, the overall waveform quality of the electric field can also be determined. This involves finding the ideal, reflection-free port voltage waveform U(t) and the overall waveform of the electric field, including stray pulses E(t), i.e., the correlation function of the entire pulse waveform considering both the main pulse and stray pulses. The maximum value of the correlation sequence is the indexed overall waveform quality of the electric field R. EU The calculation formula is shown in (7).

[0065]

[0066] If the waveform is discretized, the correlation formula for discrete sequences can also be used. R calculated from the above formula... EU When the value is less than 1, in the pulsed electric field required for the test, R EU The closer to 1, the better. In this invention, R... EU When the value is greater than 0.96, the waveform quality of the entire waveform is relatively good.

[0067] Preferably, the quality of the electric field master pulse waveform can also be used as an evaluation index. The ideal, reflection-free port voltage master pulse waveform U(t), generated by the port excitation source, and the electric field master pulse waveform E are calculated. main The correlation sequence of (t) is set with power E. f (t), then the quality of the electric field main pulse waveform R EfU To evaluate pulsed electromagnetic fields, the expression is as follows:

[0068]

[0069] If the waveform is discretized, the correlation formula for discrete sequences can also be used. The R calculated from the above formula... EfU When the value is less than 1, in the pulsed electric field required for the test, R EfU The closer to 1, the better. In this invention, when its value is greater than 0.99, the waveform quality of the main pulse is considered to be better.

[0070] Furthermore, the known variables used in the pulse voltage waveform and pulse electromagnetic field waveform of the present invention are obtained by measurement using sensors and instruments, or by circuit or electromagnetic field simulation calculations. All the above indicators reflect the parameters of the pulse electromagnetic field in different dimensions, and can be used individually or several can be combined into a parameter set for comprehensive analysis and judgment.

[0071] The present invention also provides a system for evaluating pulsed electromagnetic fields, the system comprising:

[0072] Memory, which stores executable instructions;

[0073] A processor that executes the executable instructions in the memory to implement the method.

[0074] The following examples illustrate this.

[0075] Example 1:

[0076] When the road field rotating device is a mirrored single-cone system, a cylindrical coordinate system is established with the feed point of the mirrored single cone as the origin. The maximum error is introduced by the field uniformity in the direction of the cylindrical coordinate radius ρ. When the measured object, such as an electronic device whose electromagnetic field adaptability needs to be tested, has a radial dimension of 2cm, the field uniformity error at the 2cm scale calculated by the previous uniformity index method at different locations is as follows: Figure 3 As shown. When the measured object has a radial dimension of 5 cm, the field uniformity error at the 5 cm scale calculated by the uniformity index method varies at different locations, as shown below. Figure 4 As shown in the figure. These two different calculation results demonstrate that the larger the length of the radius ρ in cylindrical coordinates, the smaller the error introduced by the uniformity of the direction field, indicating that the uniformity index method of the present invention is effective and reasonable.

[0077] Example 2:

[0078] like Figure 5The pulsed electromagnetic field shown uses the electric field waveform time window index. It can be seen that the main pulse and stray pulses have slight aliasing. However, by using this index to detect the peak time coordinates of the main pulse and stray pulses, the time delay can be detected, indicating that the method is effective.

[0079] Example 3:

[0080] like Figure 6 As shown, this is a road field conversion device with a mirror-like single-cone structure. The single-cone busbar is 2m long and has two lines with pitch angles θ = 68.5° and 85° relative to it, forming a plumb line OG. The analysis uses electric field waveform time windows and electric field stray peak amplitude ratio as evaluation indicators. The ideal non-reflective port voltage waveform is shown below. Figure 12 As shown, the voltage waveform is then obtained by taking position points on two lines with pitch angles θ = 68.5° and 85°. Figures 7-9 The pulsed electromagnetic field waveform shown is as follows, where, Figure 7 This is the case where the pitch angle θ = 68.5° and the distance from the feeder point is 0.5m. Figure 8 This is the case where the pitch angle θ = 68.5° and the distance from the feeder point is 1.25m; Figure 9 For the case of a pitch angle θ = 68.5° and a distance of 2m from the feed point, the electric field waveform time windows obtained at different locations using the time window index are as follows: Figure 10 As shown, the peak amplitude ratio of the stray electric field at different locations is used to calculate the peak amplitude of the stray electric field at different locations, for example... Figure 11 As shown. The electric field full waveform quality data obtained by calculating using the electric field full waveform quality index is as follows. Figure 13 As shown. That is Figure 7-9 Three typical cases of E(t) are given. Figure 12 Given the case of U(t), the following calculations are performed using time windows, stray peak amplitude ratio of the electric field, and the full waveform quality index of the electric field to obtain the results. Figure 10 , 11 and 13.

[0081] The foregoing description illustrates and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A method for evaluating pulsed electromagnetic fields, characterized in that, include: S1. For road field conversion devices with conical or cylindrical structures, uniformity index is used to evaluate pulsed electromagnetic fields; S1 specifically includes: S11. The power supply point of the road field conversion device is the origin of the coordinate system, and a cylindrical coordinate system or a spherical coordinate system is constructed with the direction of electromagnetic wave propagation as the radial direction. S12. Obtain the theoretical value of the electric field waveform of the road field conversion device in cylindrical or spherical coordinate system; S13. Obtain the field uniformity error of the object being measured in the electric field; S14. The uniformity index is obtained based on the theoretical value of the electric field waveform and the field uniformity error. Assume ρ is the radius coordinate in the coordinate system defined by the field conversion device, with a value of 1-10 cm; U(t) is the voltage waveform of the excitation signal, t is time, and E... c If (t) is the theoretically calculated value of the electric field waveform obtained from the excitation, then the expression is: , Among them G E It is a constant related to the directionality of the road field conversion device; assuming Δρ is the dimension of the measured object in the radial dimension of the coordinate system, the field uniformity error ΔE at this dimension is evaluated. c When, the expression is , Therefore, the obtained uniformity index The expression is: 。 2. The method for evaluating pulsed electromagnetic fields according to claim 1, characterized in that, The road field conversion device includes a mirrored single cone, a coaxial cone, or an antenna.

3. A system for evaluating pulsed electromagnetic fields, characterized in that, The system includes: Memory, which stores executable instructions; A processor that executes the executable instructions in the memory to implement the method of any one of claims 1-2.

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