Noise source impedance extraction optimization method and system considering insertion loss method sensitivity

Abstract

The invention belongs to the technical field of noise source impedance extraction, and discloses a noise source impedance extraction optimization method and system considering the sensitivity of an insertion loss method, and the method comprises the steps: extracting an equivalent circuit of noise source impedance based on the insertion loss method, and calculating a noise attenuation coefficient through the equivalent circuit, a noise source impedance amplitude and phase information are sought according to the noise attenuation coefficient; calculating relative sensitivity by using the noise source impedance amplitude and phase information, and analyzing an influence rule of a noise attenuation coefficient on noise source impedance extraction precision based on the relative sensitivity; and generating a setting rule of a noise attenuation coefficient according to the influence rule, extracting a frequency band meeting the noise source impedance requirement by using the setting rule, and determining the inductance to perform noise source impedance extraction optimization operation. According to the method, firstly, analytical expressions of noise source impedance amplitude and phase are deduced, the influence rule of the noise source impedance property on noise source impedance extraction precision is analyzed, and the requirement required to be met by noise source impedance extraction precision is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of noise source impedance extraction, and particularly to an optimization method and system for noise source impedance extraction considering the sensitivity of the insertion loss method. Background Art

[0002] In recent years, with the continuous progress of power electronics technology, high-speed switching power semiconductor devices have been widely used in various fields to improve power density. However, as the switching frequency of power semiconductor devices increases, the electromagnetic interference (EMI) problem has become increasingly serious. EMI filters are the most commonly used and effective means to suppress electromagnetic interference. Therefore, the optimal design of EMI filters has become a research hotspot. When the noise source impedance changes, the insertion loss changes greatly. Since the amplitude and phase of the common-mode and differential-mode noise source impedances of power electronic converters vary greatly with frequency, the turning frequency design method of EMI filters based on the 50Ω / 50Ω system is no longer applicable, and the influence of the noise source impedance must be considered. Therefore, noise source impedance testing is a prerequisite for realizing the optimal design of EMI filters.

[0003] Existing noise source impedance extraction methods all have certain defects: The resonance method makes a parallel connection of an inductor or a capacitor with the equivalent noise source impedance to resonate, and obtains the amplitude of the noise source impedance through the quality factor and the resonance frequency. This method has a narrow frequency band of use, a cumbersome and complex test process, and general effects; The single current probe method injects interference into the circuit through a signal generator and uses a current probe to receive the interference. The dual current probe method uses two current probes to inject and receive interference into the circuit respectively, and uses a spectrum analyzer to measure the current change before and after injecting the interference to obtain the noise source impedance. Both methods can achieve full-band noise source impedance testing, but both require high-bandwidth current probes, and have high requirements for test equipment; The traditional insertion loss method and the noise source impedance correction calculation method based on insertion loss connect an inductor in series or a capacitor in parallel between the line impedance stabilization network (LISN) and the equipment under test (EUT), and calculate the amplitude of the noise source impedance by measuring the insertion loss obtained from the noise before and after insertion, but neither can obtain the phase; The noise source impedance extraction method based on inserting a passive two-port network measures the noise current after inserting two passive two-port networks with different parameters, establishes two relationships about the real part and the imaginary part of the noise source impedance, and realizes the extraction of the amplitude and phase of the noise source impedance by means of computer programming. However, experimental results show that the extraction error is relatively large in some frequency bands, and the reason for this error has not been analyzed in the existing technology.

[0004] Therefore, how to provide an optimized method and system for extracting the impedance of a noise source considering the sensitivity of the insertion loss method is an urgent problem to be solved at present. Summary of the Invention

[0005] Embodiments of the present invention provide an optimized method and system for extracting the impedance of a noise source considering the sensitivity of the insertion loss method to solve the problem of large extraction errors in some frequency bands in the prior art.

[0006] To provide a basic understanding of some aspects of the disclosed embodiments, a simple summary is given below. This summary part is not a general review, nor is it intended to identify key / important constituent elements or delineate the protection scope of these embodiments. Its sole purpose is to present some concepts in a simple form as a prelude to the detailed description that follows.

[0007] According to a first aspect of an embodiment of the present invention, an optimized method for extracting the impedance of a noise source considering the sensitivity of the insertion loss method is provided.

[0008] In one embodiment, the optimized method for extracting the impedance of a noise source considering the sensitivity of the insertion loss method includes:

[0009] Based on the equivalent circuit for extracting the impedance of the noise source by the insertion loss method, calculate the noise attenuation coefficient using the equivalent circuit, and seek the amplitude and phase information of the noise source impedance according to the noise attenuation coefficient; calculate the relative sensitivity using the amplitude and phase information of the noise source impedance, and analyze the influence law of the noise attenuation coefficient on the extraction accuracy of the noise source impedance based on the relative sensitivity; generate a setting rule for the noise attenuation coefficient according to the influence law, extract the frequency band that meets the requirements of the noise source impedance using the setting rule, and determine the inductor based on the frequency band extraction result for the optimized operation of extracting the noise source impedance.

[0010] In one embodiment, calculating the relative sensitivity using the amplitude and phase information of the noise source impedance and analyzing the influence law of the noise attenuation coefficient on the extraction accuracy of the noise source impedance based on the relative sensitivity includes: defining an analysis basis based on the analysis requirements of the insertion loss method, and judging the accuracy of the abscissa and ordinate of the intersection point of two sets of series circles according to the analysis basis; determining the amplitude and phase of the noise source impedance according to the accuracy result, judging the series relative sensitivity of the series noise attenuation coefficient error to the amplitude and phase of the noise source impedance, and judging the extraction accuracy of the noise source impedance based on the series relative sensitivity; analyzing the corresponding relationship between the inductor and the series noise attenuation coefficient based on the series relative sensitivity, and analyzing the influence law of the series noise attenuation coefficient on the extraction accuracy of the noise source impedance according to the relationship.

[0011] In one embodiment, a setting rule for generating a noise attenuation coefficient is generated according to an influence law. A frequency band meeting the requirements of the noise source impedance is extracted by using the setting rule. Based on the frequency band extraction result, determining an inductor to perform an optimization operation for extracting the noise source impedance includes: when it is determined that the series noise attenuation coefficient is within a set interval, determining the variation laws of the series relative sensitivity of the noise source impedance amplitude and the series relative sensitivity of the noise source impedance phase with respect to the inductor and the series noise attenuation coefficient; generating a setting rule for the series noise attenuation coefficient according to the variation laws of the inductor and the series noise attenuation coefficient, and selecting an inductor meeting the requirements to perform an insertion loss method test to determine the nature of the noise source impedance; generating an extraction optimization rule based on the nature of the noise source impedance, selecting a frequency band suitable for the inductor to extract the noise source impedance according to the extraction optimization rule, and determining the series inductance value according to the frequency band selection result; substituting the series inductance value and the series noise attenuation coefficient corresponding to the frequency band into the calculation formulas for the noise source impedance amplitude and phase to extract the noise source impedance, and obtaining the frequency characteristics of the noise source impedance.

[0012] According to the second aspect of the embodiments of the present invention, an optimization system for extracting a noise source impedance considering the sensitivity of the insertion loss method is provided.

[0013] In one embodiment, an optimization system for extracting a noise source impedance considering the sensitivity of the insertion loss method includes:

[0014] An amplitude-phase calculation module, configured to extract an equivalent circuit of the noise source impedance based on the insertion loss method, calculate a noise attenuation coefficient by using the equivalent circuit, and seek noise source impedance amplitude and phase information according to the noise attenuation coefficient;

[0015] An influence law analysis module, configured to calculate a relative sensitivity by using the noise source impedance amplitude and phase information, and analyze the influence law of the noise attenuation coefficient on the extraction accuracy of the noise source impedance based on the relative sensitivity;

[0016] An impedance extraction optimization module, configured to generate a setting rule for the noise attenuation coefficient according to the influence law, extract a frequency band meeting the requirements of the noise source impedance by using the setting rule, and determine an inductor to perform an optimization operation for extracting the noise source impedance based on the frequency band extraction result.

[0017] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects:

[0018] The present invention first derives the analytical expressions for the noise source impedance amplitude and phase, analyzes the nature of the noise source impedance and the influence law of the amplitude on the extraction accuracy of the noise source impedance based on the expressions. At the same time, taking the series inductor method for extracting a highly capacitive noise source impedance as an example, analyzes the influence law of the noise attenuation on the extraction accuracy of the noise source impedance, and proposes an optimization method for the insertion loss method, and the requirements that need to be met to improve the extraction accuracy of the noise source impedance.

[0019] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and do not limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings herein are incorporated into and constitute a part of this specification, showing embodiments consistent with the present invention, and are used together with the specification to explain the principles of the present invention.

[0021] Figure 1 is a flowchart of an optimized method for extracting a noise source impedance considering the sensitivity of the insertion loss method according to an exemplary embodiment;

[0022] Figure 2 is a schematic block diagram of an optimized system for extracting a noise source impedance considering the sensitivity of the insertion loss method according to an exemplary embodiment;

[0023] Figure 3 is an equivalent circuit diagram for testing the extraction of a noise source impedance by the series inductance method according to an exemplary embodiment;

[0024] Figure 4 is an equivalent circuit diagram for testing the extraction of a noise source admittance by the parallel capacitance method according to an exemplary embodiment;

[0025] Figure 5 is S when the noise source impedance is resistive according to an exemplary embodiment La2 versus A L2 variation diagram;

[0026] Figure 6 is S when the noise source impedance is resistive according to an exemplary embodiment Ca2 versus A C2 variation diagram;

[0027] Figure 7 is when the noise source impedance is resistive according to an exemplary embodiment versus A L2 variation diagram;

[0028] Figure 8 is when the noise source impedance is resistive according to an exemplary embodiment versus A C2 variation diagram;

[0029] Figure 9 is a schematic diagram of circle 2 according to an exemplary embodiment;

[0030] Figure 10 is the corresponding relationship between L and A according to an exemplary embodiment;

[0031] Figure 11is a graph showing the variation of S with A when the noise source impedance is capacitive according to an exemplary embodiment; La2 with A L2 ;

[0032] Figure 12 is a graph showing the variation of S with A when the noise source impedance is capacitive according to an exemplary embodiment; Ca2 with A C2 ;

[0033] Figure 13 is a graph showing the variation of S with A when the noise source impedance is capacitive according to an exemplary embodiment; with A L2 ;

[0034] Figure 14 is a graph showing the variation of S with A when the noise source impedance is capacitive according to an exemplary embodiment; with A C2 ;

[0035] Figure 15 is a graph showing the variation of S with A according to an exemplary embodiment; La1 with A L11 ;

[0036] Figure 16 is a graph showing the variation of S with A according to an exemplary embodiment; with A L11 ;

[0037] Figure 17 is a graph showing the variation of S with A and L according to an exemplary embodiment; La1 with A L1 and L 1 ;

[0038] Figure 18 is a graph showing the variation of S with A and L according to an exemplary embodiment; with A L1 and L 1 ;

[0039] Figure 19 is a graph showing the variation of S with A and L according to an exemplary embodiment; La2 with A L2 and L 2 ;

[0040] Figure 20 is a graph showing the variation of S with A and L according to an exemplary embodiment; with A L2 and L 2 ;

[0041] Figure 21 is a graph showing the variation of S with A La2 with AL22 Graph of the variation law;

[0042] Figure 22 Shown according to an exemplary embodiment With respect to A L22 Graph of the variation law;

[0043] Figure 23 Schematic diagram of a Buck converter shown according to an exemplary embodiment;

[0044] Figure 24 Shown according to an exemplary embodiment of A CM1 and A CM2 Error schematic diagram;

[0045] Figure 25 Schematic diagram of the simulation extraction result of the optimization method of the insertion loss method shown according to an exemplary embodiment;

[0046] Figure 26 Schematic diagram of the simulation extraction result of the traditional insertion loss method shown according to an exemplary embodiment;

[0047] Figure 27 Schematic diagram of the experimental extraction result of the optimization method of the insertion loss method shown according to an exemplary embodiment;

[0048] Figure 28 Schematic diagram of the experimental extraction result of the traditional insertion loss method shown according to an exemplary embodiment. Detailed implementation manners

[0049] The following description and the accompanying drawings fully disclose specific embodiments herein, enabling those skilled in the art to practice them. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. The scope of the embodiments herein includes the entire scope of the claims and all available equivalents of the claims. In this document, the terms "first", "second", etc. are only used to distinguish one element from another, without requiring or implying any actual relationship or order between these elements. In fact, the first element can also be called the second element, and vice versa. Moreover, the terms "comprising", "including" or any other variants thereof are intended to cover non-exclusive inclusion, such that a structure, device or equipment comprising a series of elements not only includes those elements but also other elements not expressly listed, or also includes elements inherent to such structure, device or equipment. Without further limitation, an element defined by the statement "comprising one..." does not exclude the presence of additional identical elements in the structure, device or equipment comprising the said element. The embodiments herein are described in a progressive manner, with each embodiment highlighting the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0050] In this document, the orientation or positional relationships indicated by the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing this document and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention. In the description herein, unless otherwise specified and defined, the terms "mounted", "connected" and "coupled" shall be understood in a broad sense. For example, it may be a mechanical connection or an electrical connection, or may also be the communication inside two elements. It may be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0051] In this document, unless otherwise stated, the term "plurality" means two or more.

[0052] In this document, the character " / " indicates that the objects before and after are in an "or" relationship. For example, A / B means: A or B.

[0053] In this document, the term "and / or" is an associative relationship describing an object, indicating that three relationships can exist. For example, A and / or B means: A or B, or, A and B these three relationships.

[0054] It should be understood that although the steps in the flowchart are shown sequentially in the direction of the arrows, these steps are not necessarily executed sequentially in the order indicated by the arrows. Unless there is a clear indication in this article, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, at least a part of the steps in the figure may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed alternately or in turn with at least a part of other steps or sub-steps or stages of other steps.

[0055] Each module in the device or system of the present application can be implemented in whole or in part by software, hardware, and their combination. The above-mentioned modules can be embedded in the processor of the computer device in hardware form or independent of it, or stored in the memory of the computer device in software form, so that the processor can call and execute the operations corresponding to each of the above modules.

[0056] Without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0057] Figure 1 An embodiment of the noise source impedance extraction optimization method considering the insertion loss method sensitivity of the present invention is shown.

[0058] In this alternative embodiment, the noise source impedance extraction optimization method considering the insertion loss method sensitivity includes:

[0059] Step S101, extracting the equivalent circuit of the noise source impedance based on the insertion loss method, calculating the noise attenuation coefficient using the equivalent circuit, and seeking the amplitude and phase information of the noise source impedance according to the noise attenuation coefficient;

[0060] Step S102, calculating the relative sensitivity using the amplitude and phase information of the noise source impedance, and analyzing the influence law of the noise attenuation coefficient on the extraction accuracy of the noise source impedance based on the relative sensitivity;

[0061] Step S103, generating a setting rule for the noise attenuation coefficient according to the influence law, extracting the frequency band that meets the requirements of the noise source impedance using the setting rule, and determining the inductor based on the frequency band extraction result to perform the noise source impedance extraction optimization operation.

[0062] In this alternative embodiment, when extracting the equivalent circuit of the noise source impedance based on the insertion loss method, calculating the noise attenuation coefficient using the equivalent circuit, and seeking the amplitude and phase information of the noise source impedance based on the noise attenuation coefficient, a test equivalent circuit for extracting the noise source impedance is designed by combining the insertion loss method with the series inductance method, and two inductors with known impedances are connected in series using the equivalent circuit; the noise voltage measured at the terminal of the linear impedance stable network before and after the noise source impedance is connected in series with the inductor is analyzed using the inductor, and the series noise attenuation coefficient is calculated based on the noise voltage; the real part and the imaginary part of the noise source impedance are obtained using the series noise attenuation coefficient, and the amplitude and phase of the noise source impedance are calculated based on the results of the real part and the imaginary part.

[0063] In this alternative embodiment, when obtaining the real part and the imaginary part of the noise source impedance using the series noise attenuation coefficient and calculating the amplitude and phase of the noise source impedance based on the results of the real part and the imaginary part, the noise source impedance can be expressed as a complex number form including the real part and the imaginary part, and at the same time, the load impedance is expressed as a complex number form including the resistance and reactance parts; the obtained results are combined with the series noise attenuation coefficient to generate the series circle locus equations of two inductors with known impedances, and the abscissa and ordinate of the centers of the two circle locus equations are determined; the radii of the two series circles and the distance between the centers are analyzed based on the two series circle locus equations, and the abscissa and ordinate of the intersection points of the two series circles are obtained by combining the abscissa and ordinate of the centers; the abscissa and ordinate of the intersection points are used as the real part and the imaginary part of the noise source impedance, and the amplitude and phase of the noise source impedance are calculated based on the results of the real part and the imaginary part.

[0064] In this alternative embodiment, when calculating the relative sensitivity using the amplitude and phase information of the noise source impedance and analyzing the influence law of the noise attenuation coefficient on the extraction accuracy of the noise source impedance based on the relative sensitivity, an analysis basis can be defined according to the analysis requirements of the insertion loss method, and the accuracy of the abscissa and ordinate of the intersection points of the two series circles can be judged based on the analysis basis; the amplitude and phase of the noise source impedance are determined according to the accuracy results, the series relative sensitivity of the series noise attenuation coefficient error to the amplitude and phase of the noise source impedance is judged, and the extraction accuracy of the noise source impedance is judged based on the series relative sensitivity; the corresponding relationship between the inductor and the series noise attenuation coefficient is analyzed based on the series relative sensitivity, and the influence law of the series noise attenuation coefficient on the extraction accuracy of the noise source impedance is analyzed according to the relationship.

[0065] In this alternative embodiment, when generating the setting rules for the noise attenuation coefficient according to the influence law, extracting the frequency band that meets the requirements of the noise source impedance using the setting rules, and determining the inductor based on the frequency band extraction result for the noise source impedance extraction optimization operation, it is possible to judge that when the series noise attenuation coefficient is within a set range, the variation law of the relative sensitivity of the series noise source impedance amplitude and the relative sensitivity of the series noise source impedance phase with respect to the inductor and the series noise attenuation coefficient; generating the setting rules for the series noise attenuation coefficient according to the variation law of the inductor and the series noise attenuation coefficient, and selecting the inductor that meets the requirements to perform the insertion loss method test to judge the nature of the noise source impedance; generating the extraction optimization rules based on the nature of the noise source impedance, selecting the frequency band suitable for the inductor to extract the noise source impedance according to the extraction optimization rules, and determining the series inductance value according to the frequency band selection result; substituting the series inductance value and the series noise attenuation coefficient corresponding to the frequency band into the noise source impedance amplitude and phase calculation formula to extract the noise source impedance, and obtaining the frequency characteristics of the noise source impedance.

[0066] Figure 2 Fig. shows an embodiment of the noise source impedance extraction optimization system considering the sensitivity of the insertion loss method according to the present invention.

[0067] In this alternative embodiment, the noise source impedance extraction optimization system considering the sensitivity of the insertion loss method includes:

[0068] An amplitude-phase calculation module 201, configured to extract the equivalent circuit of the noise source impedance based on the insertion loss method, calculate the noise attenuation coefficient using the equivalent circuit, and seek the noise source impedance amplitude and phase information according to the noise attenuation coefficient;

[0069] An influence law analysis module 202, configured to calculate the relative sensitivity using the noise source impedance amplitude and phase information, and analyze the influence law of the noise attenuation coefficient on the noise source impedance extraction accuracy based on the relative sensitivity;

[0070] An impedance extraction optimization module 203, configured to generate the setting rules for the noise attenuation coefficient according to the influence law, extract the frequency band that meets the requirements of the noise source impedance using the setting rules, and determine the inductor based on the frequency band extraction result for the noise source impedance extraction optimization operation.

[0071] To facilitate the understanding of the above technical solutions of this embodiment, the working principle or operation method of this embodiment in the actual process will be described in detail below. The specific implementation steps are as follows:

[0072] Step 1: Expressions of the noise source impedance amplitude and phase;

[0073] (1) Derivation of the noise source impedance expression:

[0074] The test equivalent circuit for extracting the noise source impedance by the insertion loss method is as Figure 3 as Figure 4As shown Figure 3 is the equivalent circuit for measuring the noise source impedance by the series inductance method. V s represents the noise source voltage, Z s represents the noise source impedance, Z load represents the load impedance, Z L represents the impedance of the series inductance. V and V' respectively represent the noise voltages measured at the LISN terminals before and after the series inductance. Figure 4 is the equivalent circuit for measuring the noise source admittance by the parallel capacitance method. I s represents the noise source current, Y s represents the noise source admittance, Y load represents the load admittance, Y C represents the admittance of the parallel capacitance. I and I' respectively represent the noise currents measured at the LISN terminals before and after the parallel capacitance.

[0075] Two inductors L 1 and L 2 with known impedances are connected in series. The noise voltages are V' and V" respectively, and the noise attenuation (series noise attenuation coefficient) A L1 and A L2 are as shown in the following formula (Formula 1):

[0076]

[0077] Two capacitors C 1 and C 2 with known admittances are connected in parallel. The noise currents are I' and I" respectively, and the noise attenuation (parallel noise attenuation coefficient) A C1 and A C2 are as shown in the following formula (Formula 2):

[0078]

[0079] Define Z s or Y s as x s +jy s and Z load or Y load as c load +jb load Define the impedance Z 1 of the series inductor L L1 or the admittance Y 1 of the parallel capacitor C C1 as c 1 +jb 1 Define the impedance Z 2 of the series inductor L L2 or the admittance Y 2 of the parallel capacitor C C2 as c 2 +jb2 , substitute into Equation (1) and Equation (2), and square both sides and rearrange to get the following equation (Equation 3):

[0080]

[0081] It should be noted that when defining Z s , Z s represents the noise source impedance, which indicates the degree of obstruction of the noise source to signal transmission. It is a complex number, where x s represents the real part, specifically the resistance of the noise source (the part of current loss); jy s represents the imaginary part, specifically the reactance of the noise source (the phase difference between current and voltage); when defining Y s , Y s represents the admittance of the noise source, which is the reciprocal of the impedance. Its complex form is: x s represents the real part, specifically the conductance of the noise source (the ability of current conduction), jy s represents the imaginary part, specifically the susceptance of the noise source (the phase difference between current and voltage).

[0082] When defining Z load , Z load represents the load impedance, specifically the total obstruction of the load to the signal. In its complex form, c load is the real part, representing the resistance of the load (the part of energy dissipation), jb load is the imaginary part, representing the reactance of the load (the phase difference between current and voltage, usually caused by inductance or capacitance), and j represents the imaginary number; when defining Y load , Y load represents the admittance of the load, which is the reciprocal of the impedance. In its complex form, c load is the real part, representing the conductance of the load (the ability of current conduction), jb load is the imaginary part, representing the susceptance of the load (the phase difference between current and voltage).

[0083] When the impedance Z 1 of the series inductor L L1 is considered, Z L1 = c 1 + jb 1 represents the impedance of the series inductor L 1 . Since the impedance of the inductor is Z L = jωL, where ω represents the angular frequency and L represents the inductance value, then c 1 is the resistance part of the inductor, usually 0 (because an ideal inductor has no resistance), but there may be a small resistance in actual situations, and b 1 is the reactance part of the inductor, which is a pure imaginary number, representing the reaction of the inductor to current, with the unit of ohm, usually positive, specifically indicating that the current lags behind the voltage; for the series inductor L2 The impedance Z L2 When L2 Z = c 2 + jb 2 is similar to the impedance of a series inductor and represents the impedance of another inductor L 2 whose characteristics are similar to those of L 1 : c 2 is the resistive part of the inductor, which is 0 in the ideal case, and b 2 is the reactive part of the inductor, representing the lag of the inductor with respect to the current.

[0084] When considering the admittance of a parallel capacitor C 1 the admittance Y C1 = c 1 + jb 1 represents the admittance of the parallel capacitor C 1 and the admittance of the capacitor is Y C = jωC, where ω is the angular frequency and C is the capacitance value. Since the capacitor is a purely imaginary element, the imaginary part of the admittance is the susceptance: c 1 is the conductance part of the capacitor, and an ideal capacitor has no conductance and is usually 0, and b 1 is the susceptance part of the capacitor, which is negative and represents the phase difference between the current and the voltage, with the current lagging behind the voltage. When considering the admittance of the parallel capacitor C 2 the admittance Y C2 = c 2 + jb 2 is similar to the admittance of the parallel capacitor and represents the admittance of another capacitor C 2 : c 2 is the conductance part of the capacitor, usually 0, and b 2 is the susceptance part of the capacitor, usually negative, representing the phase difference between the current and the voltage, with the current lagging behind the voltage.

[0085] Equation (3) is the locus equation of two circles. The abscissa x 1 of the center of circle 1, the ordinate y 1 of the center of circle 1, the radius r 1 of circle 1, and the center distance D are calculated as shown in the following equation (Equation 4):

[0086]

[0087] According to Equation (3), the abscissa x s and ordinate y s of the intersection points of the two circles are calculated as shown in the following equation (Equation 5):

[0088]

[0089] The x s and y sThat is, the real part and the imaginary part of the noise source impedance. Then, the amplitude a and the phase of the noise source impedance are expressed as shown in the following formula (Formula 6):

[0090]

[0091] According to Formulas (4), (5) and (6), it can be known that c 1 , c 2 , b 1 , b 2 , A L1 or A C1 and A L2 or A C2 The measurement errors of and A s or Y s will affect the extraction accuracy of. Among them, c 1 , c 2 , b 1 and b 2 can be measured relatively accurately by a vector network analyzer. However, the measurement errors of A L1 or A C1 and A L2 or A C2 are the main reasons for the large extraction errors of the insertion loss method in some frequency bands. Therefore, analyze the influence of the measurement errors of A L1 or A C1 and A L2 or A C2 on the extraction accuracy.

[0092] (2) Sensitivity:

[0093] The insertion loss method usually uses a series inductor and a parallel capacitor with good high-frequency performance. To simplify the analysis, assume that the inductor and the capacitor have no parasitic parameters, that is, c 1 = c 2 = 0, x 1 = x 2 = -c load . At this time, x 1 - x 2 = 0, (x 1 + x 2 ) / 2 < 0. According to Formula (5), since the real part x s of the noise source impedance must be greater than 0, so ±(y 2 - y 1 ) must be positive, and Formula (5) can be simplified to the following formula (Formula 7):

[0094]

[0095] To measure A Li(i = 1, 2) The influence of the error on the extraction accuracy of the amplitude and phase of the noise source impedance extracted by the series inductance method. The relative sensitivity S of the amplitude to A Li The relative sensitivity S of the error Lai (i = 1, 2) and the sensitivity of the phase to A Li The sensitivity of the error (i = 1, 2) is specifically shown in the following formula (Formula 8):

[0096]

[0097] In the formula, S Lai represents the series relative sensitivity of the amplitude of the noise source impedance, represents the series relative sensitivity of the phase of the noise source impedance, d represents differentiation, a represents amplitude, A L1 and A L2 respectively represent the series noise attenuation coefficients corresponding to the inductances of two groups of known impedances, b L1 and b L2 represent the reactances corresponding to the inductances of two groups of known impedances, Z s represents the noise source impedance, A Li represents the series noise attenuation coefficient, represents the phase.

[0098] To measure the influence of the A Ci (i = 1, 2) error on the extraction accuracy of the amplitude and phase of the noise source impedance extracted by the parallel capacitance method, the relative sensitivity S of the amplitude to A Ci The relative sensitivity S of the error Cai (i = 1, 2) and the sensitivity of the phase to A Ci The sensitivity of the error (i = 1, 2) is specifically shown in the following formula (Formula 9):

[0099]

[0100] In the formula, S Cai represents the parallel relative sensitivity of the amplitude of the noise source impedance, represents the parallel relative sensitivity of the phase of the noise source impedance, d represents differentiation, a represents amplitude, A C1 and A C2 respectively represent the parallel noise attenuation coefficients corresponding to the capacitances of two groups of known impedances, b L1 and b L2 represent the susceptances corresponding to the capacitances of two groups of known impedances, Z s represents the noise source impedance, A Ci represents the parallel noise attenuation coefficient, represents the phase.

[0101] Based on the analysis results, it can be seen that the smaller the sensitivity, the higher the extraction accuracy.

[0102] Step 2. Sensitivity analysis;

[0103] (1) Resistive noise source impedance:

[0104] According to Equations (8) and (9), when the load impedance is 25 Ω and the noise source impedance is resistive, by adjusting the series inductance or parallel capacitance impedance, make A L1 or A C1 remain at 4, and S La2 and S Ca2 vary with A L2 and A C2 as shown in Figure 5 and Figure 6 shown. and vary with A L2 and A C2 as shown in Figure 7 and Figure 8 shown.

[0105] Based on Figure 5 , Figure 6 , Figure 7 and Figure 8 the following rules can be obtained:

[0106] 1. When A L2 or A C2 is less than A L1 or A C1 , the closer A L2 or A C2 is to A L1 or A C1 and 1, the larger S La2 or S Ca2 and or become;

[0107] 2. When A L2 or A C2 is greater than A L1 or A C1 , the larger A L2 or A C2 , the smaller S La2 or S Ca2 and or become and there is a lower limit;

[0108] 3. The larger the magnitude of the noise source impedance or admittance, the smaller S La2 or S Ca2 and or become and there is a lower limit. When the magnitude of the noise source impedance or admittance is much larger than that of the load impedance or admittance, S La2 or SCa2 Close to 0 dB;

[0109] 4. For the extraction of the resistive noise source impedance, when the magnitude of the noise source impedance is greater than that of the load impedance, the series inductor method is proposed to be used; otherwise, the parallel capacitor method is proposed to be used.

[0110] To further analyze the above conclusion, the series inductor method is taken as an example for analysis. Since the noise source impedance is resistive, so y s = 0. At this time, the schematic diagram of Circle 2 is as Figure 9 shown, and the following formula (Formula 10) can be obtained from Figure 9 :

[0111]

[0112] Assume A L2 is much larger than A L1 , and since c oad ≈ 0, the following formula (Formula 11) can be obtained:

[0113]

[0114] Substitute Formula (11) into Formula (10) to get Formula (12):

[0115] a ≈ -c load + |Z L2 | / A L2 ;

[0116] From Formula (12), it can be obtained that A L2 being much larger than A L1 is the lower limit of S La2 , as shown in the following formula (Formula 13):

[0117]

[0118] Similarly, for the parallel capacitor method, when A C2 is much larger than A C1 , the lower limit of S Ca2 is as shown in the following formula (Formula 14):

[0119]

[0120] From Formulas (13) and (14), it can be seen that: Z load / Z s or Y load / Y s is larger, the lower limit of S La2 or S Ca2 is smaller. When Z s or Y s is much larger than Z load or Y load , this lower limit is close to 0 dB, when Zs or Y s equals Z load or Y load When this happens, the lower limit is close to 6 dB, which is consistent with Figure 5 and Figure 6 the results of

[0121] (2) Capacitive and inductive noise source impedance:

[0122] Taking the capacitive noise source impedance as an example. When extracting the capacitive noise source impedance by the series inductance method, A L (series noise attenuation coefficient) may be less than 1. According to Equation (1), when the load impedance is 25 Ω, the noise source impedance is capacitive, and the frequency is 200 kHz, the corresponding relationship between the series inductance value L and A L is as follows Figure 10 shown

[0123] According to Figure 10 the following rules can be obtained:

[0124] 1. When the resonance frequency of the series inductance and the capacitive noise source impedance is 200 kHz, A L is the smallest, and the larger the amplitude of the noise source impedance, the smaller the minimum value of A L ;

[0125] 2. When the amplitude of the noise source impedance is much larger than the amplitude of the load impedance, the minimum value of A L is close to 0. When the amplitude of the noise source impedance is much smaller than the amplitude of the load impedance, the minimum value of A L is close to 1.

[0126] According to Equation (8), when the load impedance is 25 Ω, the noise source impedance is capacitive, and the frequency is 200 kHz, by adjusting the series inductance or parallel capacitance impedance to make A L1 or A C1 remain at 4, the variation rules of S La2 and S Ca2 with A L2 or A C2 are as follows Figure 11 and Figure 12 shown

[0127] According to Figure 11 and Figure 12 the following rules can be obtained:

[0128] 1. The larger the amplitude of the noise source impedance or admittance, the smaller S La2 or S Ca2 and there is a lower limit;

[0129] 2. When A L2 or A C2 is greater than A L1 or AC1 When A L2 or A C2 is larger, S La2 or S Ca2 is smaller and there is a lower limit. The larger the magnitude of the noise source impedance or admittance, the smaller this lower limit. When the magnitude of the noise source impedance or admittance is much larger than the magnitude of the load impedance or admittance, this lower limit approaches the limit value;

[0130] 3. When using the series inductance method to extract a highly capacitive noise source impedance, A L2 can be less than 1. When A L2 is much less than 1, S La2 can be below 0 dB.

[0131] According to Equation (9), when the load impedance is 25 Ω, the noise source impedance is capacitive, and the frequency is 200 kHz, by adjusting the series inductance or parallel capacitance impedance to make A L1 or A C1 remain at 4, and changes with A L2 or A C2 as shown in Figure 13 and Figure 14 .

[0132] Based on Figure 7 the following rules can be obtained:

[0133] 1. The farther the magnitude of the noise source impedance or admittance is from the magnitude of the load impedance or admittance, or is larger;

[0134] 2. When A L2 or A C2 is greater than A L1 or A C1 , when A L2 or A C2 is larger, S La2 or S Ca2 is smaller and there is a lower limit;

[0135] 3. When using the series inductance method to extract a highly capacitive noise source impedance, A L2 can be less than 1. When A L2 is much less than 1, it can be very small.

[0136] From the above analysis, it can be seen that for the extraction of the magnitude of the capacitive noise source impedance, a series inductance method should be used for a highly capacitive noise source impedance, and a parallel capacitance method should be used for a low capacitive noise impedance. However, the farther the magnitude of the noise source impedance or admittance is from the magnitude of the load impedance or admittance, or However, the larger it is, since the impedance amplitudes of capacitive and inductive noise sources vary greatly with frequency, within most frequency bands or are both large, only when the error of A (series noise attenuation coefficient or parallel noise attenuation coefficient) is small can a high-precision phase be obtained. Based on the duality principle, the above conclusion also applies to the impedance of inductive noise sources.

[0137] Step Three: Optimization method of the insertion loss method;

[0138] (1) Requirements for improving the extraction accuracy of noise source impedance:

[0139] The extraction accuracy of noise source impedances with different amplitudes can be improved by using the series inductance method or the parallel capacitance method, and during the measurement of the noise source impedance, the extraction accuracy can be improved by adjusting the magnitude of A. Limited by space, taking a high-capacitive noise source impedance as an example, the requirements for improving the extraction accuracy of the noise source impedance will be determined.

[0140] Based on the analysis in Step Two, the series inductance method should be used for high-capacitive noise source impedance. Assume that A L1 and A L2 are A when a small series inductor and a large series inductor are respectively used. From Figure 10 it can be seen that A between 0 and 1 corresponds to two different inductance values. Therefore, in this embodiment, A L1 is divided into A L11 in the descending section and A L12 in the ascending section, and A L2 is divided into A L21 in the descending section and A L22 in the ascending section.

[0141] According to Equations (8) and (9), when the load impedance is 25 Ω, the noise source impedance is a 500 pF capacitor, and the frequency is 200 kHz, A L21 are respectively 0.1, 0.3, 0.5, and 0.7, and the variation laws of S La1 and with A L11 are as shown in Figure 15 and Figure 16 .

[0142] When A L22 are respectively 0.3, 0.7, 1.1, and 10, the variation laws of S La1 and with A L11 and L 1 are as shown in Figure 17 and Figure 18 .

[0143] When A L11When they are 0.1, 0.3, 0.5, and 0.7 respectively, S La2 and vary with A L2 and L 2 as shown in Figure 19 and Figure 20 respectively.

[0144] When A L12 is 0.3, 0.5, 1.1, and 2 respectively, S La2 and vary with A L22 as shown in Figure 21 and Figure 22 respectively.

[0145] It can be seen from Figure 15 , Figure 16 , Figure 17 , Figure 18 , Figure 19 , Figure 20 , Figure 21 and Figure 22 that the variation trend of S Lai with A L1 and A L2 is the same as that of . Therefore, when A meets the requirement of small amplitude error, the phase error is also small. In this embodiment, taking S La1 and S La2 both being less than 0 dB as the standard, the requirements for improving the extraction accuracy of the impedance of a highly capacitive noise source are analyzed.

[0146] It can be seen from Figure 15 , Figure 16 that when A L1 is A L11 , and A L2 is A L21 , S La1 can only meet the standard within a very small range and is difficult to meet in actual experiments.

[0147] It can be seen from Figure 17 , Figure 18 that when A L2 is A L22 , when A L11 is less than 0.65 or A L12 is less than 1 and A L22 is greater than A L12 + 0.1, S La1 meets the standard.

[0148] It can be seen from Figure 19 , Figure 20 that when A L2 is A L22 , and A L11When it is less than 0.65, A L22 should be less than 3, S La2 can meet the standard.

[0149] From Figure 21 and Figure 22 it can be known that when A L2 is A L22 , A L12 is less than 1 and A L22 is greater than A L12 +0.1, S La2 can meet the standard.

[0150] Combining Figure 15 , Figure 16 , Figure 17 , Figure 18 , Figure 19 , Figure 20 , Figure 21 and Figure 22 , to improve the extraction accuracy of the high-capacitance noise source impedance, the requirements that A should meet are shown in the following formula (Formula 15):

[0151] or

[0152] When the measurement error becomes larger or the extraction accuracy requirement becomes higher, the requirements that A should meet should also be more stringent.

[0153] (2) Judgment of the nature of the noise source impedance:

[0154] To improve the extraction accuracy of the noise source impedance, it is necessary to judge the nature of the noise source impedance.

[0155] According to Formula (1), assuming that the series inductor with an inductance value of L is an ideal inductor, the calculation formula for the noise attenuation A is shown in the following formula (Formula 16):

[0156]

[0157] In the formula, A represents the series noise attenuation coefficient, j represents the imaginary number, f represents the frequency, L represents the inductor, and L s represents the inductance of the inductive noise source impedance.

[0158] Assuming that the series inductor impedance in the concerned frequency band is much larger than the load impedance, this assumption condition is easily achieved in the conduction frequency band. When the noise source impedance is much smaller than the load impedance, Formula (16) can be simplified to the following formula (Formula 17):

[0159]

[0160] At this time, the slope k of A changing with frequency is approximately 20 dB / dec.

[0161] When the noise source impedance is much larger than the load impedance and the noise source impedance is inductive, Equation (16) can be transformed into the following equation (Equation 18):

[0162]

[0163] At this time, k is approximately 0 dB / dec.

[0164] When the noise source impedance is much larger than the load impedance and the noise source impedance is capacitive, Equation (16) can be transformed into the following equation (Equation 19):

[0165] A≈|1 - 4π 2 f 2 LC s |;

[0166] Before the resonance frequency of the series inductor and the capacitive noise source impedance, A is less than 1 and k is negative. After the resonance frequency, k is approximately 40 dB / dec.

[0167] From the above analysis, it can be seen that according to A and k, the series inductor method can be used to judge low noise source impedance, high capacitive noise source impedance and low capacitive noise source impedance. According to the duality principle, the parallel capacitor method can be used to judge high noise source impedance, low capacitive noise source impedance and low inductive noise source impedance, as shown in Table 1:

[0168] Table 1 Judgment of the nature of the noise source impedance

[0169] Property Series inductance method Parallel capacitance method Low capacitance k ≈ 20 dB / dec A < 1, k < 0 or k ≈ 40 dB / dec Low inductance k ≈ 20 dB / dec A > 1, k ≈ 0 High capacitance A < 1, k < 0 or k ≈ 40 dB / dec k ≈ 20 dB / dec High inductance A > 1, k ≈ 0 k ≈ 20 dB / dec

[0170] (3) Optimization method of the insertion loss method:

[0171] In the process of extracting the noise source impedance by the traditional insertion loss method, only 2 inductors are used, and it is difficult to ensure that A 1 and A 2 meet the requirements in the full frequency band. Therefore, it is impossible to measure the relatively accurate noise source impedance in the full frequency band. According to Equation (15), the experimental process of the insertion loss method can be optimized. Taking the series inductor method as an example, the experimental steps of the optimized method for extracting the noise source impedance by the insertion loss method are as follows:

[0172] 1. Frequency point selection: Test the noise spectrum of the EUT in the concerned frequency band, and select several frequency points with relatively high noise amplitudes in each decade frequency range to minimize the test error of A;

[0173] 2. Judgment of the nature of the noise source impedance: Select the inductor that meets the requirements, insert and test to obtain the frequency characteristics of A, judge the nature of the noise source impedance in different frequency bands according to Table 1, and determine the frequency band suitable for extracting the noise source impedance by this inductor according to the requirements that A should meet;

[0174] 3. Determine the inductance value of the series inductor: Select L in the remaining frequency bands according to the frequency band obtained in the above steps1 and L 2 For lower-frequency bands, inductors with larger inductance values should be selected, and for higher-frequency bands, inductors with smaller inductance values should be selected. Measure the impedance-frequency characteristics of each inductor and the frequency characteristics of A after insertion testing, and determine L for different frequency bands according to the requirements. 1 and L 2 ;

[0175] 4. Calculate the noise source impedance: Substitute A L1 , A L2 , Z L1 and Z L2 at each frequency point into the analytical expressions for the magnitude and phase of the noise source impedance to calculate the frequency characteristics of the noise source impedance.

[0176] Step Four: Simulation and Experimental Verification;

[0177] To verify the feasibility and effectiveness of the proposed optimization method, use the common-mode noise source impedance of the Buck converter shown in Figure 23 as the object of simulation and experiment. The circuit parameters are shown in Table 2. The LISN parameters are set according to the electromagnetic compatibility standard GJB151B-2013. The differential and common-mode noise separation uses the voltage method. The EMI receiver and LISN used are the EM5080B of CYBERTEK and the LISN J50 of 3Ctest, respectively. For easy experimental verification, connect a 200 pF capacitor C 1 between the source and ground of the Buck switch Q s . Since the impedance of this capacitor is much smaller than the original common-mode noise source impedance of the circuit, the impedance of this capacitor can be regarded as the common-mode noise source impedance.

[0178] Table 2 Circuit Parameters

[0179] Parameter Value DC input voltage / V 30 Switching frequency / kHz 50 (simulation) / 125 (experiment) Duty cycle 0.5 <![CDATA[C s / pF]]> 200

[0180] (1) Simulation Verification: Use Ltspice to simulate the Buck converter shown in Figure 23 . The simulation step size is 10 ns. According to the experimental steps of the proposed optimization method, L 1 and L 2 for different frequency bands can be determined as shown in Table 3:

[0181] Table 3 L 1 and L 2

[0182]

[0183]

[0184] Due to the errors in the simulation software and FFT analysis, the common-mode noise attenuation ACM1 and A CM2 The error with Figure 24 is shown as follows. Using this error, the feasibility and effectiveness of the proposed optimization method can be verified.

[0185] The simulation extraction results of the optimization method by the insertion loss method are as Figure 25 shown. As can be seen from Figure 25 A CM1 and A CM2 meet the requirements in the full frequency band, and both the amplitude and phase errors of the noise source impedance are small.

[0186] The simulation extraction results of the traditional insertion loss method are as Figure 26 shown. The inductance values of the two series-connected inductors are 30 μH and 100 μH respectively. As can be seen from Figure 26 before 1.25 MHz, A CM11 is too large, and after 2.8 MHz, A CM12 is too large, both of which do not meet the requirements. At this time, the extraction errors of the amplitude and phase of the noise source impedance increase significantly, verifying the feasibility and effectiveness of the proposed requirements and optimization method.

[0187] (2) Experimental verification: In the experiment, 11 common-mode inductors with different inductance values were wound using toroidal cores of different sizes and materials, and the impedance characteristic curves of these common-mode inductors were measured using a ZLN3 vector network analyzer. In the concerned frequency band, the parasitic parameters of these common-mode inductors are very small. The experimental extraction results of the optimization method by the insertion loss method are as Figure 27 shown. As can be seen from Figure 27 A CM1 and A CM2 meet the requirements in the full frequency band, and both the amplitude and phase errors of the noise source impedance are small.

[0188] The experimental extraction results of the traditional insertion loss method are as Figure 28 shown. In the concerned frequency band, the inductance values of the two series-connected inductors are approximately 5.36 μH and 11.5 μH. As can be seen from Figure 28 before 2.5 MHz, A CM11 is too large, and after 5 MHz, A CM12 is too large, both of which do not meet the requirements. At this time, the extraction errors of the amplitude and phase of the noise source impedance increase significantly, verifying the feasibility and effectiveness of the proposed requirements and optimization method.

[0189] In this embodiment, by analyzing S Lai , , S Cai and The influence law of the nature and amplitude of the noise source impedance on the extraction accuracy of the noise source impedance is obtained. For the extraction of the resistive noise source impedance, when the amplitude of the noise source impedance is greater than that of the load impedance, the series inductor method is proposed to be used; otherwise, the parallel capacitor method is proposed to be used.

[0190] For the extraction of the amplitudes of the capacitive and inductive noise source impedances, the series inductor method should be used for high noise source impedances, and the parallel capacitor method should be used for low noise source impedances. However, the farther the amplitude of the noise source impedance or admittance is from that of the load impedance or admittance, the greater the phase sensitivity. Since the amplitudes of the capacitive and inductive noise source impedances vary greatly with frequency, the phase sensitivity is relatively large in most frequency bands, and a high accuracy can be obtained only when the error is small.

[0191] When using the series inductor method or the parallel capacitor method to extract the resistive noise source impedance, the minimum amplitude sensitivity is 0 dB. When using the series inductor method to extract a high capacitive noise source impedance or the parallel capacitor method to extract a low inductive noise source impedance, the amplitude sensitivity can be less than 0 dB, which helps to improve the extraction accuracy of the noise source impedance.

[0192] Based on the above conclusions, the influence law of the magnitude of A on the extraction accuracy of the high capacitive noise source impedance is further analyzed, and the requirements for improving the extraction accuracy of the noise source impedance and the optimization method of the insertion loss method are proposed. The simulation and experimental results both prove that this method has a higher extraction accuracy than the original method in the entire frequency band.

[0193] The present invention is not limited to the structures already described and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present invention is only limited by the appended claims.

Claims

1. A noise source impedance extraction optimization method considering the sensitivity of the insertion loss method, characterized in that: The noise source impedance extraction optimization method includes: Extract the equivalent circuit of noise source impedance based on the insertion loss method, calculate the noise attenuation coefficient using the equivalent circuit, and seek the noise source impedance amplitude and phase information based on the noise attenuation coefficient; The relative sensitivity is calculated using the noise source impedance amplitude and phase information, and the influence of the noise attenuation coefficient on the noise source impedance extraction accuracy is analyzed based on the relative sensitivity. The setting rules of the noise attenuation coefficient are generated according to the influencing rules, the frequency bands that meet the noise source impedance requirements are extracted using the setting rules, and the inductance is determined based on the frequency band extraction results to perform noise source impedance extraction optimization operations.

2. The noise source impedance extraction optimization method considering the sensitivity of the insertion loss method according to claim 1 is characterized in that: The equivalent circuit of extracting the noise source impedance based on the insertion loss method, calculating the noise attenuation coefficient using the equivalent circuit, and seeking the noise source impedance amplitude and phase information according to the noise attenuation coefficient include: Based on the insertion loss method combined with the series inductance method, an equivalent circuit for extracting noise source impedance test is designed, and two groups of inductors with known impedance are connected in series using the equivalent circuit. Use the inductor to analyze the noise source impedance before and after the linear impedance stabilizes the noise voltage measured at the network end, and calculate the series noise attenuation coefficient based on the noise voltage; The series noise attenuation coefficient is used to obtain the real and imaginary parts of the noise source impedance, and the noise source impedance magnitude and phase are calculated based on the real and imaginary results.

3. The noise source impedance extraction optimization method considering the sensitivity of the insertion loss method according to claim 2 is characterized in that: The method of obtaining the real part and the imaginary part of the noise source impedance by using the series noise attenuation coefficient, and calculating the amplitude and phase of the noise source impedance based on the real part and the imaginary part results includes: The noise source impedance is expressed as a complex number with real and imaginary parts, while the load impedance is expressed as a complex number with resistance and reactance parts; Combining the expression result with the series noise attenuation coefficient to generate the series circular trajectory equations of two groups of inductors with known impedances, and determining the horizontal and vertical coordinates of the centers of the circles corresponding to the two groups of circular trajectory equations; Based on the trajectory equations of the two sets of series circles, the radius and the distance between the centers of the two sets of series circles are analyzed, and the horizontal and vertical coordinates of the intersection of the two sets of series circles are obtained in combination with the horizontal and vertical coordinates of the centers of the circles; The horizontal and vertical coordinates of the intersection point are used as the real and imaginary parts of the noise source impedance, and the noise source impedance amplitude and phase are calculated based on the real and imaginary part results.

4. The noise source impedance extraction optimization method considering the sensitivity of the insertion loss method according to claim 1, characterized in that: The method of calculating relative sensitivity by using noise source impedance amplitude and phase information, and analyzing the influence of noise attenuation coefficient on noise source impedance extraction accuracy based on relative sensitivity includes: Define the analysis basis based on the analysis requirements of the insertion loss method, and determine the accuracy of the horizontal and vertical coordinates of the intersection of the two sets of series circles based on the analysis basis; Determine the noise source impedance amplitude and phase according to the accuracy result, judge the series relative sensitivity of the series noise attenuation coefficient error to the noise source impedance amplitude and phase, and judge the extraction accuracy of the noise source impedance based on the series relative sensitivity; The corresponding relationship between the inductance and the series noise attenuation coefficient is analyzed based on the series relative sensitivity, and the influence of the series noise attenuation coefficient on the noise source impedance extraction accuracy is analyzed based on the relationship.

5. The noise source impedance extraction optimization method considering the sensitivity of the insertion loss method according to claim 4 is characterized in that: In the influence rule of the series noise attenuation coefficient on the noise source impedance extraction accuracy, when the load impedance is 25Ω, the noise source impedance is capacitive, and the frequency is 200kHz, the series noise attenuation coefficient is the smallest, and the larger the noise source impedance amplitude, the smaller the minimum value of the series noise attenuation coefficient.

6. The noise source impedance extraction optimization method considering the sensitivity of the insertion loss method according to claim 5, characterized in that: The calculation formula of the series relative sensitivity is: In the formula, S Lai Represents the relative sensitivity of the noise source impedance amplitude in series, represents the relative sensitivity of the noise source impedance phase series connection, d represents the derivative, a represents the amplitude, A L1 With A L2 Represents the series noise attenuation coefficient corresponding to two sets of inductors with known impedances, b L1 With b L2 Represents the reactance corresponding to the inductance of two sets of known impedances, Z s represents the noise source impedance, A Li represents the series noise attenuation coefficient, Indicates phase.

7. The noise source impedance extraction optimization method considering the sensitivity of the insertion loss method according to claim 1, characterized in that: The generating of the setting rule of the noise attenuation coefficient according to the influence rule, extracting the frequency band that meets the noise source impedance requirement by using the setting rule, and determining the inductance based on the frequency band extraction result to perform the noise source impedance extraction optimization operation includes: When the series noise attenuation coefficient is determined to be within the set interval, the relative sensitivity of the noise source impedance amplitude in series and the relative sensitivity of the noise source impedance phase in series vary with the inductance and the series noise attenuation coefficient; Generate a setting rule for the series noise attenuation coefficient based on the variation rule of the inductance and the series noise attenuation coefficient, and select an inductance that meets the requirements to perform an insertion loss method test to determine the impedance properties of the noise source; Generate extraction optimization rules based on the noise source impedance properties, select a frequency band suitable for inductor extraction of noise source impedance according to the extraction optimization rules, and determine the series inductance value according to the frequency band selection result; Substitute the series noise attenuation coefficient corresponding to the series inductance value and the frequency band into the noise source impedance amplitude and phase calculation formula to extract the noise source impedance and obtain the frequency characteristics of the noise source impedance.

8. The noise source impedance extraction optimization method considering the sensitivity of the insertion loss method according to claim 7, characterized in that: The properties of the noise source impedance include low capacitance, low inductance, high capacitance and high inductance; when the noise source impedance is low capacitance, the noise source impedance is less than the load impedance, and the slope of the series noise attenuation coefficient changing with frequency is 20; when the noise source impedance is low inductance, the noise source impedance is less than the load impedance, and the slope of the series noise attenuation coefficient changing with frequency is 20; when the noise source impedance is high capacitance, the noise source impedance is greater than the load impedance, the series noise attenuation coefficient is less than 1, and the slope changing with frequency is less than 0, or the slope of the series noise attenuation coefficient changing with frequency is 40; when the noise source impedance is high capacitance, the slope of the series noise attenuation coefficient changing with frequency is 0, and the series noise attenuation coefficient is greater than 1.

9. The noise source impedance extraction optimization method considering the sensitivity of the insertion loss method according to claim 8, characterized in that: When the noise source impedance is low inductive, the calculation formula for the series noise attenuation coefficient is: Where A is the series noise attenuation factor, j is an imaginary number, f is the frequency, L is the inductance, and L is s The inductance of the inductive noise source impedance.

10. A noise source impedance extraction optimization system considering the sensitivity of the insertion loss method, characterized in that: The noise source impedance extraction optimization system includes: An amplitude and phase calculation module is used to extract the equivalent circuit of the noise source impedance based on the insertion loss method, calculate the noise attenuation coefficient using the equivalent circuit, and seek the noise source impedance amplitude and phase information according to the noise attenuation coefficient; An influence law analysis module is used to calculate relative sensitivity using noise source impedance amplitude and phase information, and analyze the influence of noise attenuation coefficient on noise source impedance extraction accuracy based on relative sensitivity; The impedance extraction optimization module is used to generate setting rules for the noise attenuation coefficient according to the influence law, extract the frequency band that meets the noise source impedance requirements using the setting rules, and determine the inductance based on the frequency band extraction results to perform noise source impedance extraction optimization operations.

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