High-precision detection method, device and equipment for broadband impedance of common-mode inductor

Abstract

The invention relates to the technical field of impedance measurement, in particular to a high-precision detection method, device and equipment for broadband impedance of a common-mode inductor, and the method comprises the steps: selecting a maximum value and a minimum value from actual impedance data, and obtaining an accurate impedance measurement value corresponding to each frequency segment; acquiring characteristic values according to the left and right data of the maximum value in the preset frequency band, and acquiring a parasitic interference degree according to the impedance measurement accurate value and the characteristic values; obtaining an interference permission degree according to the number of maximum values in a preset frequency sweeping range and a minimum frequency interval between the maximum values and the minimum values; and obtaining a weight corresponding to a maximum value according to the parasitic interference degree and the interference permission degree, fitting non-maximum values in the impedance actual data and obtaining an error, and further realizing fitting of an impedance frequency curve of the common mode inductor. According to the invention, the impedance frequency curve of the common mode inductor can be accurately obtained, so that the impedance detection is more accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of impedance measurement, and in particular to a method, device and equipment for high-precision detection of broadband impedance of a common mode inductor. Background Art

[0002] Common-mode inductors have high impedance over a wide frequency range and can effectively suppress high-frequency noise generated by high-frequency switching power supplies, so they are widely used. However, improperly designed or poorly performing common-mode inductors can cause strong electromagnetic radiation on current traces, causing electromagnetic interference to electronic and electrical components and affecting product performance. To ensure the quality of common-mode inductors, their impedance needs to be evaluated, and the accuracy of impedance measurement is critical.

[0003] In the impedance analysis process, determining the impedance of the common-mode inductor at each frequency is a key step in the measurement. At present, the least squares method is often used to fit the impedance of the common-mode inductor at different frequency bands to infer the impedance at other frequencies. However, due to the influence of many factors such as the additional impedance introduced by components, environmental factors, and the common-mode inductor's own scanning frequency band, the impedance data obtained may be interfered to varying degrees, resulting in large errors in the least squares fitting results, which in turn affects the accuracy of the common-mode inductor impedance calculation. Summary of the invention

[0004] In order to solve the problem that the impedance frequency data of the common mode inductor in the prior art is not accurate enough, resulting in poor fitting results, the purpose of the present invention is to provide a high-precision detection method for the broadband impedance of the common mode inductor. The technical solution adopted is as follows: Acquire impedance measurement data of the common mode inductor at different frequency bands, and acquire actual impedance data of the common mode inductor at different frequency bands according to the impedance measurement data; The maximum value and the minimum value are respectively selected from the actual impedance data to form a maximum value sequence and a minimum value sequence, and the maximum value sequence and the minimum value sequence are respectively fitted to obtain a maximum value curve and a minimum value curve, and the impedance measurement accurate value corresponding to each frequency segment is obtained according to the maximum value curve and the minimum value curve, wherein each frequency segment contains only one frequency corresponding to the maximum value; Respectively determine the left data and the right data of the maximum value in the preset frequency band, obtain the characteristic value corresponding to the maximum value according to the left data and the right data, and obtain the parasitic interference degree according to the impedance measurement accurate value and the characteristic value; Obtaining the number of the maximum values ​​within a preset frequency sweep range, analyzing the minimum frequency interval between the maximum value and the minimum value, and obtaining the interference tolerance corresponding to the maximum value according to the number and the minimum frequency interval; The weight corresponding to the maximum value is obtained according to the parasitic interference degree and the interference allowance, the non-maximum value in the actual impedance data is fitted and the error corresponding to each non-maximum value is obtained, the inverse of the error is used as the weight corresponding to the non-maximum value, and the impedance frequency curve of the common mode inductor is fitted according to the weight corresponding to each actual impedance data.

[0005] Furthermore, the process of acquiring the actual impedance data includes: Clustering the impedance measurement data in any frequency band to obtain at least two clusters, and obtaining an average value of the impedance measurement data in each cluster as a representative impedance value of the cluster; The absolute value of the difference between the impedance representative values ​​corresponding to the two types of clusters is used as the measured impedance difference value, and on the center line of the two types of clusters, the projection length of the impedance representative value of each type of cluster in the direction of the center line is obtained respectively; Obtaining the sum of the projection lengths corresponding to the two types of clusters respectively, and subtracting the sum of the projection lengths from the measured impedance difference value to obtain an impedance error value of the free gap between the two types of clusters; The average value of the difference between any two impedance measurement data in each cluster is taken as the impedance difference average value, the sum of the impedance difference average values ​​corresponding to the two clusters is calculated, and the impedance error value is divided by the sum of the impedance difference average values ​​to obtain the cluster difference value between the two clusters; Repeat the cluster difference value acquisition process to obtain the cluster difference value between any two clusters, and calculate the average value of the cluster difference value as the cluster difference average value; The actual impedance data of the common mode inductor in the frequency band is obtained according to the cluster difference average value and the impedance representative value.

[0006] Further, obtaining actual impedance data of the common mode inductor in the frequency band according to the cluster difference average value and the impedance representative value includes: Obtaining the cluster difference average value and the impedance representative value corresponding to the i-th cluster, wherein the value range of i is 1 to the number of clusters; Obtaining the sum of the cluster difference averages corresponding to each cluster; The impedance actual component corresponding to the i-th cluster is obtained by multiplying the cluster difference average value corresponding to the i-th cluster by the impedance representative value of the i-th cluster and then dividing the result by the sum of the cluster difference average values; Repeat the process of obtaining the actual impedance component to obtain the actual impedance component corresponding to each cluster; The actual impedance components are added in sequence to obtain the actual impedance data of the common mode inductor in the frequency band.

[0007] Further, obtaining the accurate impedance measurement value corresponding to each frequency segment according to the maximum value curve and the minimum value curve includes: In the frequency segment, the maximum value curve and the minimum value curve are respectively integrated to obtain a maximum value integration result and a minimum value integration result; Dividing the maximum value integration result and the minimum value integration result by the length of the frequency segment respectively to obtain a maximum value average integration result and a minimum value average integration result, and subtracting the minimum value average integration result from the maximum value average integration result to obtain an extreme value average integration difference value; Obtaining a maximum parameter vector and a minimum parameter vector respectively corresponding to the maximum curve and the minimum curve in the frequency segment, and obtaining a parameter vector norm by taking a norm after subtracting the minimum parameter vector from the maximum parameter vector; The parameter vector norm is multiplied by the extreme value average integral difference value and then normalized to obtain a normalized result, and the impedance measurement accurate value under the frequency segment is obtained by subtracting the normalized result from a preset first value; The process of obtaining the accurate impedance measurement value is repeated to obtain the accurate impedance measurement value in each frequency segment.

[0008] Further, obtaining the characteristic value corresponding to the maximum value according to the left data and the right data includes: The slope of the curve after the left data is fitted is recorded as the left slope, and the slope of the curve after the right data is fitted is recorded as the right slope; The difference between the maximum value and the minimum value in the left data is obtained and recorded as the left difference value, and the difference between the maximum value and the minimum value in the right data is obtained and recorded as the right difference value; The left slope minus the right slope is used as the input value of the exponential function with base e, the left difference is added to the right difference to obtain the sum of the left and right differences, the sum of the left and right differences is multiplied by the output value of the exponential function, and then normalized to obtain the eigenvalue corresponding to the maximum value.

[0009] Further, obtaining the parasitic interference degree according to the impedance measurement accurate value and the characteristic value includes: The characteristic value is divided by the impedance measurement accurate value to obtain the parasitic interference level.

[0010] Further, acquiring the interference tolerance corresponding to the maximum value according to the quantity and the minimum frequency interval includes: The minimum frequency interval is divided by the number to obtain the interference tolerance corresponding to the maximum value.

[0011] Further, obtaining the weight corresponding to the maximum value according to the parasitic interference degree and the interference tolerance includes: The parasitic interference degree is multiplied by the interference allowable degree and then normalized to obtain an interference normalization value, a preset second value is subtracted from the interference normalization value to obtain an impedance fitting weight, and the impedance fitting weight is normalized to obtain a weight corresponding to the maximum value.

[0012] The embodiment of the present invention further provides a high-precision detection device for broadband impedance of common mode inductors, the device comprising: An impedance actual data module is used to obtain impedance measurement data of common mode inductors at different frequency bands, and obtain impedance actual data of the common mode inductors at different frequency bands according to the impedance measurement data; An impedance measurement accurate value module, used to select the maximum value and the minimum value from the actual impedance data to form a maximum value sequence and a minimum value sequence, and to fit the maximum value sequence and the minimum value sequence to obtain a maximum value curve and a minimum value curve, respectively, and to obtain the impedance measurement accurate value corresponding to each frequency segment according to the maximum value curve and the minimum value curve, wherein each frequency segment contains only one frequency corresponding to the maximum value; A parasitic interference degree module, used to respectively determine the left data and the right data of the maximum value in a preset frequency band, obtain the characteristic value corresponding to the maximum value according to the left data and the right data, and obtain the parasitic interference degree according to the impedance measurement accurate value and the characteristic value; An interference tolerance module, used to obtain the number of the maximum values ​​within a preset frequency sweep range, analyze the minimum frequency interval between the maximum value and the minimum value, and obtain the interference tolerance corresponding to the maximum value according to the number and the minimum frequency interval; A weight fitting module is used to obtain the weight corresponding to the maximum value according to the parasitic interference degree and the interference allowance, fit the non-maximum value in the actual impedance data and obtain the error corresponding to each non-maximum value, use the inverse of the error as the weight corresponding to the non-maximum value, and realize the fitting of the impedance frequency curve of the common mode inductor according to the weight corresponding to each actual impedance data.

[0013] An embodiment of the present invention also provides a high-precision detection device for broadband impedance of common-mode inductors, the device comprising a processor and a memory storing computer program instructions; the processor reads and executes the computer program instructions to implement the steps of the above method.

[0014] The present invention has the following beneficial effects: Obtain impedance measurement data of common mode inductors in different frequency bands, and obtain actual impedance data of the common mode inductors in different frequency bands according to the impedance measurement data. The actual impedance data is more accurate than the impedance measurement data. Select the maximum value and the minimum value from the actual impedance data to form a maximum value sequence and a minimum value sequence, and fit the maximum value sequence and the minimum value sequence to obtain a maximum value curve and a minimum value curve, and obtain the impedance measurement accuracy corresponding to each frequency segment according to the maximum value curve and the minimum value curve, wherein each frequency segment contains only one frequency corresponding to the maximum value. The larger the impedance measurement accuracy value, the higher the measurement accuracy of the impedance data. Determine the left data and the right data of the maximum value in the preset frequency band respectively, obtain the characteristic value corresponding to the maximum value according to the left data and the right data, and obtain the parasitic interference degree according to the impedance measurement accuracy value and the characteristic value. The larger the parasitic interference degree, the lower the accuracy of the impedance data. Obtain the number of the maximum values ​​within the preset frequency sweep range, analyze the minimum frequency interval between the maximum value and the minimum value, and obtain the interference tolerance corresponding to the maximum value according to the number and the minimum frequency interval. The larger the interference tolerance, the larger the error of the allowed parasitic interference degree. Obtain the weight corresponding to the maximum value according to the parasitic interference degree and the interference tolerance, fit the non-maximum values ​​in the actual impedance data and obtain the error corresponding to each non-maximum value, use the inverse of the error as the weight corresponding to the non-maximum value, and implement the fitting of the impedance frequency curve of the common-mode inductor according to the weight corresponding to each actual impedance data. After determining the weight of each impedance data, complete the fitting of the impedance frequency curve of the common-mode inductor, the fitting result is more accurate, and then the impedance of the common-mode inductor is obtained more accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A flowchart of a high-precision detection method for broadband impedance of a common-mode inductor provided by the first embodiment of the present invention; Figure 2 A flowchart of a process for obtaining actual impedance data provided by the second embodiment of the present invention; Figure 3Another flow chart of the process of obtaining actual impedance data provided by the third embodiment of the present invention; Figure 4 A flowchart of a process for obtaining an accurate impedance measurement value provided by a fourth embodiment of the present invention; Figure 5 A flowchart of a process for obtaining characteristic values ​​provided in a fifth embodiment of the present invention; Figure 6 It is a schematic diagram of a high-precision detection device for broadband impedance of a common-mode inductor provided by a sixth embodiment of the present invention. DETAILED DESCRIPTION

[0017] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the broadband impedance high-precision detection method, device and equipment of a common mode inductor proposed by the present invention, its specific implementation method, structure, features and effects in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0018] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0019] The specific scheme of a method, device and equipment for high-precision detection of broadband impedance of a common-mode inductor provided by the present invention is described in detail below in conjunction with the accompanying drawings.

[0020] See also Figure 1 , which shows a flow chart of a method for high-precision detection of broadband impedance of a common-mode inductor provided by a first embodiment of the present invention, the method comprising: S101. Obtain impedance measurement data of common mode inductors at different frequency bands, and obtain actual impedance data of the common mode inductors at different frequency bands according to the impedance measurement data.

[0021] Use a test fixture to connect the common mode inductor to be tested to the impedance analyzer, adjust the scanning frequency band of the impedance analyzer, and obtain the impedance of the common mode inductor in different frequency bands. The scanning frequency band is adjusted step by step from low frequency to high frequency, and the impedance of the common mode inductor is measured multiple times in each frequency band, so as to obtain an orderly impedance measurement data sequence: . Represents the impedance of the common mode inductor corresponding to the mth scanning frequency band in the kth impedance measurement data sequence, wherein the value of k is 1 to the number of the impedance measurement data sequences, and the value range of m is 1 to the number of the scanning frequency bands.

[0022] The process of acquiring the actual impedance data will be described in detail in the second embodiment and the third embodiment, and will not be repeated here.

[0023] S102. Select the maximum value and the minimum value from the actual impedance data to form a maximum value sequence and a minimum value sequence, and fit the maximum value sequence and the minimum value sequence to obtain a maximum value curve and a minimum value curve, respectively, and obtain the accurate impedance measurement value corresponding to each frequency segment according to the maximum value curve and the minimum value curve, wherein each frequency segment contains only one frequency corresponding to the maximum value.

[0024] The extreme point detection algorithm in the prior art may be used to select the maximum value and the minimum value from the actual impedance data.

[0025] The process of obtaining the accurate impedance measurement value will be described in detail in the fourth embodiment and will not be repeated here.

[0026] That is to say, there are as many frequency segments as there are maxima.

[0027] S103. Determine the left data and the right data of the maximum value in the preset frequency band respectively, obtain the characteristic value corresponding to the maximum value according to the left data and the right data, and obtain the degree of parasitic interference according to the impedance measurement accurate value and the characteristic value.

[0028] In the preset frequency band, data on the left side of the frequency corresponding to the maximum value is left data, and data on the right side of the frequency corresponding to the maximum value is right data.

[0029] The process of obtaining the characteristic value will be described in detail in the fifth embodiment and will not be repeated here.

[0030] The parasitic interference degree is obtained according to the impedance measurement accurate value and the characteristic value, specifically including: dividing the characteristic value by the impedance measurement accurate value to obtain the parasitic interference degree.

[0031] The parasitic interference degree can be expressed as: ; Wherein, t represents the parasitic interference degree, b represents the characteristic value, Indicates the accurate value of the impedance measurement.

[0032] S104. Obtain the number of the maximum values ​​within the preset frequency sweep range, analyze the minimum frequency interval between the maximum value and the minimum value, and obtain the interference tolerance corresponding to the maximum value according to the number and the minimum frequency interval.

[0033] The minimum frequency interval refers to the minimum absolute value of the difference between the frequency corresponding to the maximum value and the frequency corresponding to the minimum value. In other words, the minimum frequency interval refers to the frequency interval between the maximum value and the minimum value closest to it.

[0034] Acquiring the interference tolerance corresponding to the maximum value according to the quantity and the minimum frequency interval, specifically including: The minimum frequency interval is divided by the number to obtain the interference tolerance corresponding to the maximum value.

[0035] When measuring impedance data in different frequency bands, the appearance of peaks is not only affected by the setting of the scanning frequency step size, but also significantly depends on the span of the scanning frequency. When the frequency span is large, it is normal to have large impedance changes between adjacent data points, which may result in no extreme values ​​in a large frequency range. At this time, large changes in impedance are considered normal. At the same time, due to the large frequency range and few data points, it is normal to have significant differences between the upper and lower extreme values ​​of impedance. However, under this condition, the impact of family planning interference is aggravated, which may cause normal common-mode inductor impedance to be misjudged as abnormal interference value.

[0036] Therefore, a frequency fluctuation threshold η is set for the maximum value, and the actual measurement data is screened out through this threshold as the basis for frequency sweep analysis. It is worth noting that the frequency sweep range and frequency band are different in definition: the former is defined by the number of fixed common mode inductor impedance maximum points, while the latter is based on a fixed frequency interval length.

[0037] All impedance maximum points must be identified within the specified sweep frequency range. If there are fewer maximum points and the frequency intervals between them are larger, the risk of misjudging the degree of parasitic interference is higher, and significant interference phenomena may be mistaken for normal impedance changes. Therefore, in this case, the interference tolerance should be appropriately relaxed. The greater the interference tolerance, the greater the allowed parasitic interference error.

[0038] On the one hand, the smaller the impedance interference tolerance is, the higher the accuracy of the parasitic interference degree obtained through the frequency characteristics is, thus giving a larger fitting weight to this type of common-mode inductor impedance. On the other hand, the smaller the parasitic interference degree of the impedance is, the more the impedance obtained reflects the actual impedance measured by the real impedance analyzer, thus giving a larger weight. On the contrary, if there is parasitic interference in the impedance, it usually causes the measured impedance of the common-mode inductor to be larger, thus giving a smaller weight, and adjusting the impedance measurement result through the weight.

[0039] The interference tolerance can be expressed as: ; Among them, the represents the interference tolerance, the represents the minimum frequency interval, and n represents the number.

[0040] S105. Obtain the weight corresponding to the maximum value according to the parasitic interference degree and the interference allowance, fit the non-maximum values ​​in the actual impedance data and obtain the error corresponding to each non-maximum value, use the inverse of the error as the weight corresponding to the non-maximum value, and implement the fitting of the impedance frequency curve of the common mode inductor according to the weight corresponding to each actual impedance data.

[0041] Obtaining a weight corresponding to the maximum value according to the parasitic interference degree and the interference tolerance specifically includes: The parasitic interference degree is multiplied by the interference allowable degree and then normalized to obtain an interference normalization value, a preset second value is subtracted from the interference normalization value to obtain an impedance fitting weight, and the impedance fitting weight is normalized to obtain a weight corresponding to the maximum value.

[0042] The impedance fitting weight can be expressed as: ; Among them, the represents the impedance fitting weight, the norm represents a normalization function, such as a range normalization function. The t represents the parasitic interference degree, the Represents the preset second value, and the preset second value threshold may be 1.

[0043] The impedance fitting weights corresponding to the maximum values ​​may be obtained by repeating the process of obtaining the impedance fitting weights corresponding to the maximum values.

[0044] The impedance fitting weight may be normalized as follows: ; Among them, the represents the impedance fitting weight, the represents the sum of the impedance fitting weights, the Represents the normalized result corresponding to the w.

[0045] The weights corresponding to the respective maximum values ​​may be obtained by repeating the process of obtaining the weights corresponding to the maximum values.

[0046] After selecting a frequency band to be analyzed, obtain the common mode inductor impedance data measured multiple times in this frequency band. Given that the impedance of common mode inductors in high frequency bands is generally large, even normal impedance measurement errors may cause significant changes in impedance values. Therefore, if judgment is made based solely on the similarity between impedance values, there may be a greater risk of misjudgment. To avoid this, it is necessary to comprehensively consider the distribution fluctuation characteristics of these impedance data and combine them with their similarity to other measured impedances to more accurately evaluate the reliability of the measurement data.

[0047] Figure 2 This is a flow chart of a process for obtaining actual impedance data provided by a second embodiment of the present invention. The process for obtaining actual impedance data includes: S201. Cluster the impedance measurement data in any frequency band to obtain at least two clusters, and obtain an average value of the impedance measurement data in each cluster as a representative impedance value of the cluster.

[0048] The clustering method may be a Density-Peaks clustering algorithm, which obtains the local density of each impedance measurement data, reflecting the similarity between different impedance measurement data under the same scanning frequency band.

[0049] The impedance value of the cluster center is the impedance representative value.

[0050] S202. Taking the absolute value of the difference between the impedance representative values ​​corresponding to the two types of clusters as the measured impedance difference value, and obtaining the projection length of the impedance representative value of each cluster in the direction of the center line on the center line of the two types of clusters.

[0051] The greater the impedance difference between different clusters and the larger the free impedance gap between clusters, it indicates that there is obvious fluctuation in the impedance data of the current scanning frequency band, which further indicates that the impedance data is more obviously disturbed by parasitic parameters, and thus the measurement accuracy of the impedance data is lower.

[0052] The measured impedance difference between the i-th cluster and the j-th cluster can be expressed as: ; Among them, the represents the measured impedance difference between the i-th cluster and the j-th cluster, represents the impedance representative value of the i-th cluster, Represents the impedance representative value of the j-th cluster.

[0053] S203. Obtain the sum of the projection lengths corresponding to the two types of clusters respectively, and subtract the sum of the projection lengths from the measured impedance difference value to obtain the impedance error value of the free gap between the two types of clusters.

[0054] The impedance error value can be expressed as: ; Among them, the represents the impedance error value, the represents the measured impedance difference between the i-th cluster and the j-th cluster, represents the sum of the projection lengths, where represents the projection length of the impedance representative value of the ith cluster in the direction of the center line, Represents the projection length of the impedance representative value of the j-th cluster in the direction of the center line.

[0055] The larger the free gap is, the more obvious the difference is between the measured impedances, which means that the repeatability of the impedance measurement results is poor, there is obvious parasitic parameter interference in the actual measurement process, and the impedance accuracy is poor.

[0056] S204. Take the average value of the difference between any two impedance measurement data in each cluster as the impedance difference average value, calculate the sum of the impedance difference average values ​​corresponding to the two clusters, and divide the impedance error value by the sum of the impedance difference average values ​​to obtain the cluster difference value between the two clusters.

[0057] The cluster difference value can be expressed as: ; Among them, the represents the cluster difference value, the represents the impedance error value, the represents the average impedance difference corresponding to the i-th cluster, Represents the average impedance difference corresponding to the j-th cluster.

[0058] When the impedance value is large, the measurement result itself will be accompanied by a large fluctuation error. In view of this, the average difference in impedance within each cluster is calculated. If the impedance difference reflected by the two free gaps is similar to or smaller than this average difference, it can be inferred that the impedance difference of these free gaps is within the normal measurement fluctuation range.

[0059] S205. Repeat the process of obtaining the cluster difference value to obtain the cluster difference value between any two clusters, and calculate the average value of the cluster difference value as the cluster difference average value.

[0060] If the impedance difference of a cluster center is closer to the impedance differences of the other cluster centers, it means that the impedance is more likely to represent the impedance value of the real common mode inductor.

[0061] S206. Obtain actual impedance data of the common mode inductor in the frequency band according to the cluster difference average value and the impedance representative value.

[0062] The method of obtaining the actual impedance data of the common mode inductor in the frequency band according to the cluster difference average value and the impedance representative value will be described in detail in the third embodiment and will not be repeated here.

[0063] Figure 3 Another flowchart of the process of obtaining the actual impedance data provided by the third embodiment of the present invention, obtaining the actual impedance data of the common mode inductor in the frequency band according to the cluster difference average value and the impedance representative value includes: S301. Obtain the cluster difference average value and the impedance representative value corresponding to the i-th cluster, wherein the value range of i is 1 to the number of clusters.

[0064] The cluster difference mean can be used To express.

[0065] S302. Obtain the sum of the cluster difference averages corresponding to each cluster.

[0066] The sum of the cluster difference means can be expressed as: , that is, add up the average values ​​of the cluster differences corresponding to each cluster.

[0067] S303. After multiplying the cluster difference average value corresponding to the ith cluster by the impedance representative value of the ith cluster, the resultant value is divided by the sum of the cluster difference average values ​​to obtain the impedance actual component corresponding to the ith cluster.

[0068] The actual component of impedance corresponding to the i-th cluster can be expressed as: , wherein the represents the impedance representative value of the i-th cluster, represents the sum of the average values ​​of the cluster differences, Represents the average value of the cluster differences corresponding to the i-th cluster.

[0069] S304. Repeat the process of acquiring the actual impedance component to obtain the actual impedance component corresponding to each type of cluster.

[0070] S305. Add the actual impedance components in sequence to obtain actual impedance data of the common mode inductor in the frequency band.

[0071] ; Among them, the It represents the actual impedance data of the common mode inductor in the frequency band, and the value range of i is from 1 to the number of clusters.

[0072] The above process uses the Density-Picks clustering technology to perform cluster anomaly detection on the impedance data within the same scanning frequency band, thereby verifying the authenticity of the measured impedance and determining the actual impedance value of the scanning frequency band accordingly.

[0073] However, on the other hand, it should be noted that the impedance of the common-mode inductor may be significantly affected by the frequency, resulting in the impedance data obtained in this frequency band generally containing relatively obvious parasitic parameters. In this case, the aforementioned method is difficult to effectively distinguish the interference caused by significant parasitic parameters in multiple measurements of the common-mode inductor in a certain frequency band, which in turn causes the impedance data obtained in the scanned frequency band to have large errors and reduce accuracy. In addition, the extreme values ​​obtained for the common-mode inductor have an important influence on the final fitting results and require special attention.

[0074] If the frequency band factors cause the interference of parasitic parameters, it will induce a certain degree of impedance peak phenomenon in the local range. Specifically, when the common mode inductor or measurement fixture and other components introduce parasitic parameters, it may cause LC resonance in the circuit at a specific frequency, which will lead to an abnormal increase in the impedance amplitude and form an obvious peak (maximum value). The appearance of these abnormal peaks will disturb the impedance performance of the common mode inductor in the frequency domain, causing it to show abnormal fluctuations, thereby destroying the original change trend of the impedance.

[0075] Figure 4 The flowchart of the process of obtaining the accurate impedance measurement value provided by the fourth embodiment of the present invention, wherein obtaining the accurate impedance measurement value corresponding to each frequency segment according to the maximum value curve and the minimum value curve includes: S401. In the frequency segment, respectively integrate the maximum value curve and the minimum value curve to obtain a maximum value integration result and a minimum value integration result.

[0076] The maximum value integral result can be expressed as: , where the integration interval is the frequency segment.

[0077] The minimum value integral result can be expressed as: , where the integration interval is the frequency segment.

[0078] Under normal circumstances, the maximum value curve is similar to the minimum value curve and has the same variation trend, which reflects the impedance variation of the common mode inductor.

[0079] The maximum value change curve is used as the segmentation standard of the curve, and the scanning frequency is segmented according to the maximum value (such as The frequency band consists of a maximum value, and each frequency band corresponds to an impedance data of a maximum value).

[0080] S402. Divide the maximum value integration result and the minimum value integration result by the length of the frequency segment to obtain a maximum value average integration result and a minimum value average integration result, and subtract the minimum value average integration result from the maximum value average integration result to obtain an extreme value average integration difference value.

[0081] The maximum average integral result can be expressed as: , where L is the length of the frequency segment.

[0082] The minimum average integral result can be expressed as: , where L is the length of the frequency segment.

[0083] The extreme value average integral difference value can be expressed as: ; Among them, the represents the extreme value average integrated difference value.

[0084] The extreme value average integral difference reflects the fluctuation of impedance within the scanning frequency band, indicating that the smaller the allowable impedance fluctuation error of the two curves, under this condition, if the maximum impedance change and the minimum impedance change of the common mode inductor have the same trend characteristics, it means that the measurement accuracy of the impedance data is higher.

[0085] The extreme average integral difference value effectively quantifies the fluctuation of impedance within the scanning frequency range, indicating that when the impedance fluctuation error allowed by the two curves is smaller, if the maximum impedance change and the minimum impedance change of the common mode inductor show consistent trend characteristics, this directly indicates that the impedance data measurement has higher accuracy.

[0086] S403. Obtain a maximum parameter vector and a minimum parameter vector respectively corresponding to the maximum curve and the minimum curve in the frequency segment, and obtain a parameter vector norm by subtracting the minimum parameter vector from the maximum parameter vector.

[0087] The parameter vector norm can be expressed as: ; Among them, the represents the maximum parameter vector, represents the minimum parameter vector, Represents the norm function.

[0088] It should be noted that the maximum value parameter and the minimum value parameter are obtained by locally fitting the impedance of the frequency segment, rather than fitting the entire maximum value curve and the minimum value curve.

[0089] S404. The parameter vector norm is multiplied by the extreme value average integral difference value and then normalized to obtain a normalized result, and a preset first value is subtracted from the normalized result to obtain the accurate impedance measurement value under the frequency segment.

[0090] The accurate value of the impedance measurement can be expressed as: ; Among them, the is a normalization function, such as a range normalization function, represents the preset first value, the preset first value threshold may be 1, Indicates the accurate value of the impedance measurement.

[0091] S405. Repeat the process of obtaining the accurate impedance measurement value to obtain the accurate impedance measurement value in each frequency segment.

[0092] If a local peak is caused by parasitic parameter interference, a significant impedance change will occur in the local frequency band. The greater the difference between the local impedance change trend and the global trend, the greater the degree to which the local impedance peak in the area is interfered by the parasitic parameters, and the lower the accuracy of the impedance measurement.

[0093] Select an actual impedance with a maximum value as the benchmark, obtain all actual impedance values ​​in the entire frequency band, and perform local fitting on these impedances (different from the previous extreme value fitting). If there are obvious trends and amplitude changes on both sides of the local peak, this usually means that the impedance of this frequency band is abnormally affected by parasitic parameters, resulting in reduced data accuracy. On the contrary, if the maximum and minimum impedance curves are highly consistent in trend despite the presence of a significant local peak, this indicates that the local peak may be a normal resonance phenomenon in the common mode inductor. In this case, the impedance measurement data is considered to be accurate because the local peak does not deviate significantly from the overall trend, reflecting the high accuracy of the measurement. Therefore, the consistency of the local peak of impedance with the global trend becomes a key indicator for evaluating measurement accuracy and identifying parasitic parameter interference.

[0094] Figure 5 The flowchart of the process of obtaining the characteristic value provided by the fifth embodiment of the present invention, wherein obtaining the characteristic value corresponding to the maximum value according to the left data and the right data includes: S501. Record the slope of the curve after the left data is fitted as the left slope, and record the slope of the curve after the right data is fitted as the right slope.

[0095] The fitting method may be the least squares method or the like.

[0096] When the impedance peak appears, the left side shows an upward trend and the right side shows a downward trend. The greater the difference between the left and right sides, the more obvious the impedance change trend at the corresponding frequency.

[0097] S502. Obtain the difference between the maximum value and the minimum value in the left data and record it as the left difference value, and obtain the difference between the maximum value and the minimum value in the right data and record it as the right difference value.

[0098] The left difference and the right difference reflect the amplitude change.

[0099] S503. Subtract the right slope from the left slope and use it as the input value of the exponential function with base e, add the left difference to the right difference to get the sum of the left and right differences, multiply the sum of the left and right differences by the output value of the exponential function, and then perform normalization to obtain the eigenvalue corresponding to the maximum value.

[0100] The characteristic value can be expressed as: ; Among them, the represents the eigenvalue, the represents a normalization function, such as a range normalization function, represents an exponential function with the natural constant e as the base, represents the left slope, the represents the right side slope, the represents the left difference, the represents the right side difference.

[0101] Said It reflects the trend of the impedance peak and the change in its amplitude, indicating the characteristics of the peak.

[0102] Figure 6 A schematic diagram of a high-precision detection device for broadband impedance of a common-mode inductor provided by a sixth embodiment of the present invention, the device comprising: The impedance actual data module 601 is used to obtain impedance measurement data of the common mode inductor in different frequency bands, and obtain the impedance actual data of the common mode inductor in different frequency bands according to the impedance measurement data; The impedance measurement accurate value module 602 is used to select the maximum value and the minimum value from the actual impedance data to form a maximum value sequence and a minimum value sequence, and respectively fit the maximum value sequence and the minimum value sequence to obtain a maximum value curve and a minimum value curve, and obtain the impedance measurement accurate value corresponding to each frequency segment according to the maximum value curve and the minimum value curve, wherein each frequency segment contains only one frequency corresponding to the maximum value; The parasitic interference degree module 603 is used to respectively determine the left data and the right data of the maximum value in the preset frequency band, obtain the characteristic value corresponding to the maximum value according to the left data and the right data, and obtain the parasitic interference degree according to the impedance measurement accurate value and the characteristic value; The interference tolerance module 604 is used to obtain the number of the maximum values ​​within the preset frequency sweep range, analyze the minimum frequency interval between the maximum value and the minimum value, and obtain the interference tolerance corresponding to the maximum value according to the number and the minimum frequency interval; The weight fitting module 605 is used to obtain the weight corresponding to the maximum value according to the parasitic interference degree and the interference allowance, fit the non-maximum values ​​in the actual impedance data and obtain the error corresponding to each non-maximum value, use the inverse of the error as the weight corresponding to the non-maximum value, and realize the fitting of the impedance frequency curve of the common mode inductor according to the weight corresponding to each actual impedance data.

[0103] The technical features and technical effects of a high-precision detection device for wide-band impedance of a common-mode inductor proposed in an embodiment of the present invention are the same as those of the method proposed in an embodiment of the present invention, and are not described in detail herein.

[0104] An embodiment of the present invention also provides a high-precision detection device for broadband impedance of common-mode inductors, the device comprising a processor and a memory storing computer program instructions; the processor reads and executes the computer program instructions to implement the steps of the above method.

[0105] The present invention has the following beneficial effects: Obtain impedance measurement data of common mode inductors in different frequency bands, and obtain actual impedance data of the common mode inductors in different frequency bands according to the impedance measurement data. The actual impedance data is more accurate than the impedance measurement data. Select the maximum value and the minimum value from the actual impedance data to form a maximum value sequence and a minimum value sequence, and fit the maximum value sequence and the minimum value sequence to obtain a maximum value curve and a minimum value curve, and obtain the impedance measurement accuracy corresponding to each frequency segment according to the maximum value curve and the minimum value curve, wherein each frequency segment contains only one frequency corresponding to the maximum value. The larger the impedance measurement accuracy value, the higher the measurement accuracy of the impedance data. Determine the left data and the right data of the maximum value in the preset frequency band respectively, obtain the characteristic value corresponding to the maximum value according to the left data and the right data, and obtain the parasitic interference degree according to the impedance measurement accuracy value and the characteristic value. The larger the parasitic interference degree, the lower the accuracy of the impedance data. Obtain the number of the maximum values ​​within the preset frequency sweep range, analyze the minimum frequency interval between the maximum value and the minimum value, and obtain the interference tolerance corresponding to the maximum value according to the number and the minimum frequency interval. The larger the interference tolerance, the larger the error of the allowed parasitic interference degree. Obtain the weight corresponding to the maximum value according to the parasitic interference degree and the interference tolerance, fit the non-maximum values ​​in the actual impedance data and obtain the error corresponding to each non-maximum value, use the inverse of the error as the weight corresponding to the non-maximum value, and implement the fitting of the impedance frequency curve of the common-mode inductor according to the weight corresponding to each actual impedance data. After determining the weight of each impedance data, complete the fitting of the impedance frequency curve of the common-mode inductor, the fitting result is more accurate, and then the impedance of the common-mode inductor is obtained more accurately.

[0106] It should be noted that the sequence of the above embodiments of the present invention is for description only and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0107] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. A high-precision detection method for broadband impedance of common mode inductors, characterized in that: The method comprises: Obtaining impedance measurement data of the common mode inductor at different frequency bands, and obtaining actual impedance data of the common mode inductor at different frequency bands according to the impedance measurement data; The maximum value and the minimum value are respectively selected from the actual impedance data to form a maximum value sequence and a minimum value sequence, and the maximum value sequence and the minimum value sequence are respectively fitted to obtain a maximum value curve and a minimum value curve, and the impedance measurement accurate value corresponding to each frequency segment is obtained according to the maximum value curve and the minimum value curve, wherein each frequency segment contains only one frequency corresponding to the maximum value; Respectively determine the left data and the right data of the maximum value in the preset frequency band, obtain the characteristic value corresponding to the maximum value according to the left data and the right data, and obtain the parasitic interference degree according to the impedance measurement accurate value and the characteristic value; Obtaining the number of the maximum values ​​within a preset frequency sweep range, analyzing the minimum frequency interval between the maximum value and the minimum value, and obtaining the interference tolerance corresponding to the maximum value according to the number and the minimum frequency interval; The weight corresponding to the maximum value is obtained according to the parasitic interference degree and the interference allowance, the non-maximum value in the actual impedance data is fitted and the error corresponding to each non-maximum value is obtained, the inverse of the error is used as the weight corresponding to the non-maximum value, and the impedance frequency curve of the common mode inductor is fitted according to the weight corresponding to each actual impedance data.

2. The high-precision detection method for broadband impedance of common mode inductors according to claim 1, characterized in that: The process of obtaining the actual impedance data includes: Clustering the impedance measurement data in any frequency band to obtain at least two clusters, and obtaining an average value of the impedance measurement data in each cluster as a representative impedance value of the cluster; The absolute value of the difference between the impedance representative values ​​corresponding to the two types of clusters is used as the measured impedance difference value, and on the center line of the two types of clusters, the projection length of the impedance representative value of each type of cluster in the direction of the center line is obtained respectively; Obtaining the sum of the projection lengths corresponding to the two types of clusters respectively, and subtracting the sum of the projection lengths from the measured impedance difference value to obtain an impedance error value of the free gap between the two types of clusters; The average value of the difference between any two impedance measurement data in each cluster is taken as the impedance difference average value, the sum of the impedance difference average values ​​corresponding to the two clusters is calculated, and the impedance error value is divided by the sum of the impedance difference average values ​​to obtain the cluster difference value between the two clusters; Repeat the cluster difference value acquisition process to obtain the cluster difference value between any two clusters, and calculate the average value of the cluster difference value as the cluster difference average value; The actual impedance data of the common mode inductor in the frequency band is obtained according to the cluster difference average value and the impedance representative value.

3. The high-precision detection method for broadband impedance of common mode inductors according to claim 2, characterized in that: Obtaining actual impedance data of the common mode inductor in the frequency band according to the cluster difference average value and the impedance representative value includes: Obtaining the cluster difference average value and the impedance representative value corresponding to the i-th cluster, wherein the value range of i is 1 to the number of clusters; Obtaining the sum of the cluster difference averages corresponding to each cluster; The impedance actual component corresponding to the i-th cluster is obtained by multiplying the cluster difference average value corresponding to the i-th cluster by the impedance representative value of the i-th cluster and then dividing the result by the sum of the cluster difference average values; Repeat the process of obtaining the actual impedance component to obtain the actual impedance component corresponding to each cluster; The actual impedance components are added in sequence to obtain the actual impedance data of the common mode inductor in the frequency band.

4. The high-precision detection method for broadband impedance of common mode inductors according to claim 1, characterized in that: Obtaining the accurate impedance measurement value corresponding to each frequency segment according to the maximum value curve and the minimum value curve includes: In the frequency segment, the maximum value curve and the minimum value curve are respectively integrated to obtain a maximum value integration result and a minimum value integration result; Dividing the maximum value integration result and the minimum value integration result by the length of the frequency segment respectively to obtain a maximum value average integration result and a minimum value average integration result, and subtracting the minimum value average integration result from the maximum value average integration result to obtain an extreme value average integration difference value; Obtaining a maximum parameter vector and a minimum parameter vector respectively corresponding to the maximum curve and the minimum curve in the frequency segment, and obtaining a parameter vector norm by taking a norm after subtracting the minimum parameter vector from the maximum parameter vector; The parameter vector norm is multiplied by the extreme value average integral difference value and then normalized to obtain a normalized result, and the normalized result is subtracted from a preset first value to obtain the accurate impedance measurement value under the frequency segment; The process of obtaining the accurate impedance measurement value is repeated to obtain the accurate impedance measurement value in each frequency segment.

5. The high-precision detection method for broadband impedance of common mode inductors according to claim 1, characterized in that: Obtaining the characteristic value corresponding to the maximum value according to the left data and the right data includes: The slope of the curve after the left data is fitted is recorded as the left slope, and the slope of the curve after the right data is fitted is recorded as the right slope; The difference between the maximum value and the minimum value in the left data is obtained and recorded as the left difference value, and the difference between the maximum value and the minimum value in the right data is obtained and recorded as the right difference value; The left slope minus the right slope is used as the input value of the exponential function with base e, the left difference is added to the right difference to obtain the sum of the left and right differences, the sum of the left and right differences is multiplied by the output value of the exponential function, and then normalized to obtain the eigenvalue corresponding to the maximum value.

6. The high-precision detection method for broadband impedance of common mode inductors according to claim 1, characterized in that: Obtaining the parasitic interference degree according to the impedance measurement accurate value and the characteristic value includes: The characteristic value is divided by the impedance measurement accurate value to obtain the parasitic interference level.

7. The high-precision detection method for broadband impedance of common mode inductors according to claim 1, characterized in that: Acquiring the interference tolerance corresponding to the maximum value according to the quantity and the minimum frequency interval includes: The minimum frequency interval is divided by the number to obtain the interference tolerance corresponding to the maximum value.

8. The high-precision detection method for broadband impedance of common mode inductors according to claim 1, characterized in that: Obtaining the weight corresponding to the maximum value according to the parasitic interference degree and the interference tolerance includes: The parasitic interference degree is multiplied by the interference allowable degree and then normalized to obtain an interference normalization value, a preset second value is subtracted from the interference normalization value to obtain an impedance fitting weight, and the impedance fitting weight is normalized to obtain a weight corresponding to the maximum value.

9. A high-precision detection device for broadband impedance of common mode inductors, characterized in that: The device comprises: An impedance actual data module is used to obtain impedance measurement data of common mode inductors at different frequency bands, and obtain impedance actual data of the common mode inductors at different frequency bands according to the impedance measurement data; An impedance measurement accurate value module, used to select the maximum value and the minimum value from the actual impedance data to form a maximum value sequence and a minimum value sequence, and to fit the maximum value sequence and the minimum value sequence to obtain a maximum value curve and a minimum value curve, respectively, and to obtain the impedance measurement accurate value corresponding to each frequency segment according to the maximum value curve and the minimum value curve, wherein each frequency segment contains only one frequency corresponding to the maximum value; A parasitic interference degree module, used to respectively determine the left data and the right data of the maximum value in a preset frequency band, obtain the characteristic value corresponding to the maximum value according to the left data and the right data, and obtain the parasitic interference degree according to the impedance measurement accurate value and the characteristic value; An interference tolerance module, used to obtain the number of the maximum values ​​within a preset frequency sweep range, analyze the minimum frequency interval between the maximum value and the minimum value, and obtain the interference tolerance corresponding to the maximum value according to the number and the minimum frequency interval; A weight fitting module is used to obtain the weight corresponding to the maximum value according to the parasitic interference degree and the interference allowance, fit the non-maximum value in the actual impedance data and obtain the error corresponding to each non-maximum value, use the inverse of the error as the weight corresponding to the non-maximum value, and realize the fitting of the impedance frequency curve of the common mode inductor according to the weight corresponding to each actual impedance data.

10. A high-precision broadband impedance detection device for common mode inductors, characterized in that: The device comprises a processor and a memory storing computer program instructions; the processor reads and executes the computer program instructions to implement the steps of the method according to any one of claims 1 to 8.

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