Inductance test method and system

Abstract

The invention relates to the technical field of inductance testing, in particular to an inductance testing method and system, and the method comprises the steps: building an inductance digital model; solving an impedance characteristic curve of the inductance digital model under different frequencies based on an equivalent circuit equation, selecting an optimal test frequency point, and applying a sine excitation signal with a set amplitude at the optimal test frequency point; calculating response data under the action of the excitation signal through an equivalent circuit equation of the inductance digital model, and reversely calculating an actual inductance value in combination with parameters of the inductance digital model; and adjusting parameters of the inductance digital model, repeatedly executing backstepping calculation until the maximum number of times is reached, outputting an inductance measurement result combination, performing statistical analysis on the inductance measurement result combination, and completing comprehensive evaluation of the inductance performance. According to the method, the uncertainty of the measurement result is scientifically evaluated, and the measurement requirements of inductors of different specifications can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of inductance testing, and in particular to an inductance testing method and system. Background Art

[0002] As a key basic component in electronic circuits, the accurate measurement of inductance performance parameters is of great significance to the design and quality control of electronic products. Inductance measurement technology has gone through a development process from simple LCR testers to complex network analyzers. With the rapid development of electronic technology, inductance devices have evolved towards high frequency, miniaturization, and high precision. Traditional measurement methods can no longer meet the accuracy requirements of inductance measurement in the modern electronics industry. At present, the traditional inductance measurement technology mainly has the following problems: on the one hand, the influence of the distributed parameters of the inductance is not fully considered during the measurement process, resulting in a deviation between the measurement results and the performance under the actual application state; on the other hand, the selection of the measurement frequency point lacks a scientific basis, and often uses empirical fixed frequency points, which cannot guarantee the optimality of the measurement results and cannot meet the requirements of the modern electronics industry for measurement accuracy. Based on this, in response to the above problems, we designed an inductance test method and system. Summary of the invention

[0003] The purpose of the present invention is to provide an inductance testing method and system, which transforms inductance measurement into a parameter identification problem by establishing an inductance digital model. On the one hand, the digital model comprehensively considers the influence of the distributed parameters of the inductance and improves the accuracy of the measurement result. On the other hand, the optimal test frequency is selected by impedance characteristic curve analysis to ensure the optimality of the measurement result. In addition, the present invention adopts multiple measurements and statistical analysis methods to realize scientific evaluation of the uncertainty of the measurement result, can adapt to the inductance measurement requirements of different specifications, and has good versatility.

[0004] The present invention is achieved through the following technical solutions:

[0005] An inductance testing method, the method comprising the steps of:

[0006] Establish the framework of inductor digital model;

[0007] Input the nominal parameters of the inductor to be tested into the inductor digital model framework, and set the test conditions to form the inductor digital model;

[0008] Based on the equivalent circuit equation, the impedance characteristic curve of the inductor digital model at different frequencies is solved, and the optimal test frequency point is selected, and a sinusoidal excitation signal with a set amplitude is applied at the optimal test frequency point;

[0009] Calculate the response data under the action of the excitation signal through the equivalent circuit equation of the inductor digital model;

[0010] Based on the response data and the parameters of the inductor digital model, the actual inductance value is calculated and represented as the inductance measurement result;

[0011] The parameters of the inductor digital model are adjusted, and the reverse calculation is repeated until the maximum number of times is reached. The combination of inductor measurement results is output, and the combination of inductor measurement results is statistically analyzed to complete the comprehensive evaluation of inductor performance.

[0012] Optionally, the nominal parameters of the inductor to be measured include: nominal inductance value, series resistance and distributed capacitance.

[0013] Optionally, the calculation formula of the inductance digital model framework is:

[0014]

[0015] Where Z is the total impedance of the inductor equivalent circuit, R s is the series resistance, L is the inductance, C p is the distributed capacitance, ω is the angular frequency, and j is the imaginary unit.

[0016] Optionally, the impedance characteristic curve of the inductor digital model at different frequencies is solved based on the equivalent circuit equation, and the calculation formula is:

[0017]

[0018] ω opt =2πf opt

[0019] Where Z(ω) is the impedance modulus, R(ω) is the frequency-dependent equivalent resistance, X(ω) is the frequency-dependent equivalent reactance, φ(ω) is the impedance phase angle, Z(ω)=f(ω), ω∈[ω1,ω2] is the impedance-frequency characteristic curve, ω1, ω2 are the start and end angular frequencies of the sweep range, respectively, ω opt is the optimal test angular frequency, f opt is the optimal test frequency.

[0020] Optionally, the response data includes: voltage response, current response and phase difference.

[0021] Optionally, the voltage response is calculated as follows:

[0022] v(t)=V m sin(ω opt t)

[0023] The calculation formula of the current response is:

[0024] i(t)=I m sin(ω opt t-φ)

[0025] The calculation formula of the phase difference is:

[0026]

[0027] Where v(t) is the voltage response, i(t) is the current response, φ is the phase difference, V m ,I m are the voltage and current amplitudes respectively, and t is the time.

[0028] Optionally, the statistical analysis of the combination of inductance measurement results is specifically performed as follows:

[0029] Obtaining a combination of inductance measurement results, and calculating an arithmetic mean of the combination of inductance measurement results;

[0030]

[0031] Calculate the standard deviation based on the arithmetic mean;

[0032]

[0033] Solve the standard uncertainty of type A and type B respectively;

[0034]

[0035]

[0036] Calculate the combined standard uncertainty based on the standard uncertainties of types A and B;

[0037]

[0038] Determine the expanded uncertainty and output the final inductance measurement result;

[0039]

[0040] U=k*u c

[0041] in, is the arithmetic mean, x i is the i-th inductance measurement result, n is the number of measurements, s is the standard deviation, u A 、u B are the standard uncertainties of type A and type B respectively, a i is the half width of the i-th error source, m is the number of error sources, u c is the combined standard uncertainty, k is the coverage factor, U is the expanded uncertainty, and L' is the final measurement result of the inductance.

[0042] An inductance testing system, comprising:

[0043] An inductor digital model building unit is used to build an inductor digital model framework, input the nominal parameters of the inductor to be tested into the inductor digital model framework, and set test conditions to form an inductor digital model;

[0044] The calculation unit solves the impedance characteristic curve of the inductor digital model at different frequencies based on the equivalent circuit equation, selects the best test frequency point, applies a sinusoidal excitation signal of a set amplitude at the best test frequency point, calculates the response data under the action of the excitation signal through the equivalent circuit equation of the inductor digital model, and reversely calculates the actual inductance value based on the response data and the parameters of the inductor digital model, which is represented as the inductance measurement result;

[0045] The statistical analysis unit adjusts the parameters of the inductor digital model and repeatedly performs the reverse calculation until the maximum number of times is reached, outputs a combination of inductor measurement results, performs statistical analysis on the combination of inductor measurement results, and completes a comprehensive evaluation of the inductor performance.

[0046] The technical solution of the present invention has at least the following advantages and beneficial effects:

[0047] The present invention transforms inductance measurement into a parameter identification problem by establishing an inductance digital model. On the one hand, the digital model comprehensively considers the influence of the distributed parameters of the inductance and improves the accuracy of the measurement result. On the other hand, the optimal test frequency is selected through impedance characteristic curve analysis to ensure the optimality of the measurement result. In addition, the present invention adopts multiple measurements and statistical analysis methods to realize scientific evaluation of the uncertainty of the measurement result, can adapt to the measurement requirements of inductances of different specifications, and has good versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 A schematic flow chart of an inductance testing method provided by the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, what is described is only a part of the present invention, not all of it. Generally, the components of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0050] like Figure 1 As shown, the present invention provides one embodiment: an inductance testing method, the steps of the method comprising:

[0051] Establish the framework of inductor digital model;

[0052] Input the nominal parameters of the inductor to be tested into the inductor digital model framework, and set the test conditions to form the inductor digital model;

[0053] Based on the equivalent circuit equation, the impedance characteristic curve of the inductor digital model at different frequencies is solved, and the optimal test frequency point is selected, and a sinusoidal excitation signal with a set amplitude is applied at the optimal test frequency point;

[0054] Calculate the response data under the action of the excitation signal through the equivalent circuit equation of the inductor digital model;

[0055] Based on the response data and the parameters of the inductor digital model, the actual inductance value is calculated and represented as the inductance measurement result;

[0056] The parameters of the inductor digital model are adjusted, and the reverse calculation is repeated until the maximum number of times is reached. The combination of inductor measurement results is output, and the combination of inductor measurement results is statistically analyzed to complete the comprehensive evaluation of inductor performance.

[0057] In this embodiment, the basic framework of the inductor digital model mainly includes four aspects: first, determine the basic structure of the inductor equivalent circuit, topologically connect the three basic components of ideal inductance, series resistance and distributed capacitance according to their physical characteristics to form a complete equivalent circuit; second, establish the mathematical expression of each component, including the impedance equation of ideal inductance, series resistance and distributed capacitance, and derive the synthetic impedance expression of the entire circuit; third, construct the state equation of the circuit, and describe the dynamic characteristics of the circuit through the three basic equations of voltage, current and power; fourth, complete the parameterization setting of the model, and determine the variable definition, value range and mutual relationship of each parameter. Based on the construction of the above four aspects, this embodiment forms a basic framework of the inductor digital model that can be used for simulation analysis.

[0058] Furthermore, the nominal parameters of the inductor to be measured include: nominal inductance value, series resistance and distributed capacitance.

[0059] In implementation, this embodiment imports the nominal parameters of the inductor to be tested into the basic parameters such as the nominal value of the inductor, the series resistance and the distributed capacitance provided by the manufacturer. Then, according to the actual application scenario, the test conditions are set, including external factors such as the test frequency range, the excitation signal amplitude and the ambient temperature, and these parameters and test conditions are integrated into the digital model to form a complete computable model. It can be understood that the test conditions include conventional test conditions such as the set temperature.

[0060] The calculation formula of the inductance digital model framework is:

[0061]

[0062] Where Z is the total impedance of the inductor equivalent circuit, Rs is the series resistance, L is the inductance, C p is the distributed capacitance, ω is the angular frequency, and j is the imaginary unit.

[0063] In this embodiment, the impedance characteristic analysis process is specifically as follows: within a set frequency range, the impedance value and phase angle of the inductor at different frequency points are calculated by an equivalent circuit equation; an impedance-frequency characteristic curve is drawn to analyze the frequency response characteristics of the inductor; based on the impedance characteristic curve, a point in the linear working area of ​​the inductor and where the impedance is insensitive to frequency changes is selected as the optimal test frequency, and a sinusoidal excitation signal with a determined amplitude is applied at the frequency point. The specific calculation formula is as follows:

[0064]

[0065] ω opt =2πf opt

[0066] Where Z(ω) is the impedance modulus, R(ω) is the frequency-dependent equivalent resistance, X(ω) is the frequency-dependent equivalent reactance, φ(ω) is the impedance phase angle, Z(ω)=f(ω), ω∈[ω1,ω2] is the impedance-frequency characteristic curve, ω1, ω2 are the start and end angular frequencies of the sweep range, respectively, ω opt is the optimal test angular frequency, f opt The optimal test frequency.

[0067] Specifically, the response data includes: voltage response, current response and phase difference.

[0068] During implementation, this embodiment inputs the set sinusoidal excitation signal into the inductor digital model, calculates the voltage response and current response of the inductor under the excitation through the equivalent circuit equation, calculates the phase difference between the voltage and current, and obtains complete response characteristic data.

[0069] The voltage response is calculated as:

[0070] v(t)=V m sin(ω opt t)

[0071] The calculation formula of the current response is:

[0072] i(t)=I m sin(ω opt t-φ)

[0073] The calculation formula of the phase difference is:

[0074]

[0075] Where v(t) is the voltage response, i(t) is the current response, φ is the phase difference, V m ,I m are the voltage and current amplitudes respectively, and t is the time.

[0076] More specifically, this embodiment calculates the actual impedance value and phase angle based on the obtained voltage and current response data, combines the parameters of the inductor digital model, reversely solves the actual inductance value through the equivalent circuit equation, and uses the calculated inductance value as a valid measurement result.

[0077] In the specific application of this embodiment, the statistical analysis of the inductance measurement result combination is specifically as follows:

[0078] Obtaining a combination of inductance measurement results, and calculating an arithmetic mean of the combination of inductance measurement results;

[0079]

[0080] Calculate the standard deviation based on the arithmetic mean;

[0081]

[0082] Solve the standard uncertainty of type A and type B respectively;

[0083]

[0084] Calculate the combined standard uncertainty based on the standard uncertainties of types A and B;

[0085]

[0086] Determine the expanded uncertainty and output the final inductance measurement result;

[0087]

[0088] U=k*u c

[0089] Among them, x is the arithmetic mean, x i is the i-th inductance measurement result, n is the number of measurements, s is the standard deviation, u A 、u B are the standard uncertainties of type A and type B respectively, a i is the half width of the i-th error source, m is the number of error sources, u c is the combined standard uncertainty, k is the coverage factor, U is the expanded uncertainty, and L' is the final measurement result of the inductance.

[0090] In another embodiment of the present invention, an inductance testing system includes:

[0091] An inductor digital model building unit is used to build an inductor digital model framework, input the nominal parameters of the inductor to be tested into the inductor digital model framework, and set test conditions to form an inductor digital model;

[0092] The calculation unit solves the impedance characteristic curve of the inductor digital model at different frequencies based on the equivalent circuit equation, selects the best test frequency point, applies a sinusoidal excitation signal of a set amplitude at the best test frequency point, calculates the response data under the action of the excitation signal through the equivalent circuit equation of the inductor digital model, and reversely calculates the actual inductance value based on the response data and the parameters of the inductor digital model, which is represented as the inductance measurement result;

[0093] The statistical analysis unit adjusts the parameters of the inductor digital model and repeatedly performs the reverse calculation until the maximum number of times is reached, outputs a combination of inductor measurement results, performs statistical analysis on the combination of inductor measurement results, and completes a comprehensive evaluation of the inductor performance.

[0094] The above is only the preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An inductance testing method, characterized in that: The steps of the method include: Establish the framework of inductor digital model; Input the nominal parameters of the inductor to be tested into the inductor digital model framework, and set the test conditions to form the inductor digital model; Based on the equivalent circuit equation, the impedance characteristic curve of the inductor digital model at different frequencies is solved, and the optimal test frequency point is selected, and a sinusoidal excitation signal with a set amplitude is applied at the optimal test frequency point; Calculate the response data under the action of the excitation signal through the equivalent circuit equation of the inductor digital model; Based on the response data and the parameters of the inductor digital model, the actual inductance value is calculated and represented as the inductance measurement result; The parameters of the inductor digital model are adjusted, and the reverse calculation is repeated until the maximum number of times is reached. The combination of inductor measurement results is output, and the combination of inductor measurement results is statistically analyzed to complete the comprehensive evaluation of inductor performance.

2. The inductance testing method according to claim 1, characterized in that: The nominal parameters of the inductor to be measured include: nominal inductance value, series resistance and distributed capacitance.

3. The inductance testing method according to claim 2, characterized in that: The calculation formula of the inductance digital model framework is: Where Z is the total impedance of the inductor equivalent circuit, R s is the series resistance, L is the inductance, C p is the distributed capacitance, ω is the angular frequency, and j is the imaginary unit.

4. The inductance testing method according to claim 3, characterized in that: The impedance characteristic curve of the inductor digital model at different frequencies is solved based on the equivalent circuit equation, and the calculation formula is: oh opt =2πf opt Where Z(ω) is the impedance modulus, R(ω) is the frequency-dependent equivalent resistance, X(ω) is the frequency-dependent equivalent reactance, φ(ω) is the impedance phase angle, Z(ω)=f(ω), ω∈[ω1,ω2] is the impedance-frequency characteristic curve, ω1, ω2 are the start and end angular frequencies of the sweep range, respectively, ω opt is the optimal test angular frequency, f opt is the optimal test frequency.

5. The inductance testing method according to claim 4, characterized in that: The response data includes: voltage response, current response and phase difference.

6. The inductance testing method according to claim 5, characterized in that: The voltage response is calculated as: v(t)=V m sin(ω opt t) The calculation formula of the current response is: i(t)=I m sin(ω opt t-φ) The calculation formula of the phase difference is: Where v(t) is the voltage response, i(t) is the current response, φ is the phase difference, V m ,I m are the voltage and current amplitudes respectively, and t is the time.

7. The inductance testing method according to claim 6, characterized in that: The statistical analysis of the combination of inductance measurement results is specifically as follows: Obtaining a combination of inductance measurement results, and calculating an arithmetic mean of the combination of inductance measurement results; Calculate the standard deviation based on the arithmetic mean; Solve the standard uncertainty of type A and type B respectively; Calculate the combined standard uncertainty based on the standard uncertainties of types A and B; Determine the expanded uncertainty and output the final inductance measurement result; U=k*u c in, is the arithmetic mean, x i is the i-th inductance measurement result, n is the number of measurements, s is the standard deviation, u A 、u B are the standard uncertainties of type A and type B respectively, a i is the half width of the i-th error source, m is the number of error sources, u c is the combined standard uncertainty, k is the coverage factor, U is the expanded uncertainty, and L' is the final measurement result of the inductance.

8. An inductance testing system, characterized in that: include: An inductor digital model building unit is used to build an inductor digital model framework, input the nominal parameters of the inductor to be tested into the inductor digital model framework, and set test conditions to form an inductor digital model; The calculation unit solves the impedance characteristic curve of the inductor digital model at different frequencies based on the equivalent circuit equation, selects the best test frequency point, applies a sinusoidal excitation signal of a set amplitude at the best test frequency point, calculates the response data under the action of the excitation signal through the equivalent circuit equation of the inductor digital model, and reversely calculates the actual inductance value based on the response data and the parameters of the inductor digital model, which is represented as the inductance measurement result; The statistical analysis unit adjusts the parameters of the inductor digital model and repeatedly performs the reverse calculation until the maximum number of times is reached, outputs a combination of inductor measurement results, performs statistical analysis on the combination of inductor measurement results, and completes a comprehensive evaluation of the inductor performance.

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