A capacitive self-adaptive measurement method and device based on measurement accuracy constraint and medium

Abstract

The application discloses a kind of based on measurement accuracy constraint's capacitance adaptive measurement method, device and medium, it is related to electronic measurement technical field.The minimum effective voltage variation is determined according to system resolution and preset measurement accuracy, so that the voltage variation participating in capacity calculation can satisfy the effective resolution ability requirement of measurement system.Meanwhile, whether the measured capacitance reaches stable state is judged by the change relation between multiple capacity estimation values, so that the measurement error caused by the fluctuation of capacitance capacity estimation value due to the electrochemical characteristics of capacitance can be effectively reduced.The measurement is ended and the capacity value is output after meeting the preset stable condition, without using fixed measurement time or fixed cutoff voltage, the measurement process can be adaptively adjusted according to actual measurement state, while ensuring the accuracy of capacity measurement, reduce redundant sampling time, improve the measurement efficiency of different capacity range capacitors.

Description

Technical Field

[0001] This invention relates to the field of electronic measurement technology, and in particular to a capacitance adaptive measurement method, device, and medium based on measurement accuracy constraints. Background Technology

[0002] Capacitance measurement is widely used in electronic component testing, battery management systems, automated testing equipment, and precision instruments. The constant current charging method is widely applied to capacitance measurement due to its simple measurement principle and ease of implementation. Its basic principle is as follows: a constant current is used to charge the capacitor under test. The constant current source charging current is I. The charging time Δt corresponding to the change in capacitor voltage, and the change in capacitor voltage ΔV, are used to calculate the estimated capacitance value according to the following formula: ; Existing constant current charging methods calculate the capacitance of the capacitor under test after a fixed measurement time or a fixed cutoff voltage, failing to fully consider the resolution of the measurement system and the dynamic characteristics of the capacitor itself. On one hand, when the voltage change involved in the calculation is small, factors such as the resolution of the analog-to-digital converter and system noise significantly affect the capacitance calculation results. Furthermore, a fixed measurement time or fixed cutoff voltage makes it difficult to adaptively determine the effective sampling data volume for different capacitance ranges and measurement accuracy requirements. On the other hand, the actual capacitor is affected by its electrochemical characteristics during charging. Before the capacitor reaches a steady state, the voltage change rate may differ at different charging stages, resulting in different voltage changes for the same charging time. This leads to fluctuations in the calculated capacitance estimate. Since existing technologies typically perform a single capacitance calculation under fixed measurement time or fixed cutoff voltage conditions without determining whether the capacitor under test has entered a steady state, longer measurement times or higher cutoff voltages are often required to ensure measurement accuracy. This results in redundant sampling, reduced measurement efficiency, and difficulty in balancing measurement accuracy and efficiency for capacitors of different capacitances. Summary of the Invention

[0003] The purpose of this invention is to provide a capacitance adaptive measurement method, device, and medium based on measurement accuracy constraints, which solves the problem that existing capacitance measurement methods cannot adaptively determine the amount of sampling data and are difficult to balance the measurement accuracy and measurement efficiency of capacitors with different capacities.

[0004] To address the aforementioned technical problems, this invention provides a capacitance adaptive measurement method based on measurement accuracy constraints, comprising: Determine the system resolution and preset measurement accuracy; The minimum effective voltage change is determined based on the system resolution and the preset measurement accuracy. The capacitor voltage is continuously monitored, and based on the change in capacitor voltage obtained from the continuous monitoring, when the change in capacitor voltage meets the minimum effective voltage change requirement, a capacitor capacity estimate is calculated to obtain multiple capacitor capacity estimates. Determine whether the relationship between multiple estimated capacitance values ​​meets the preset stability condition; If so, output the final capacitance value; If not, continue to detect the capacitor voltage and calculate the estimated capacitor capacity until the preset stability condition is met.

[0005] Optionally, determine whether the relationship between multiple estimated capacitance values ​​satisfies a preset stability condition, including: The relative rate of change between adjacent estimated capacitance values ​​is less than a preset rate of change threshold. And / or, the standard deviation of multiple capacitance estimates is less than a preset standard deviation threshold; And / or, the coefficient of variation of multiple capacitance estimates is less than a preset coefficient of variation threshold.

[0006] Optionally, the system resolution is determined based on the reference voltage of the measurement system and the effective noise-free resolution bits or the effective resolution bits.

[0007] Optional, also includes: The system noise voltage of the measurement system is obtained, and the minimum effective voltage change is superimposed and corrected based on the system noise voltage.

[0008] Optionally, the final capacitance value is output, including: The latest calculated capacitance estimate that meets the preset stability condition is determined as the final capacitance value and output. Alternatively, the average value of a set of estimated capacitance values ​​that meet the preset stability conditions can be determined as the final capacitance value and output. Alternatively, the median of a set of estimated capacitance values ​​that meet the preset stability conditions can be determined as the final capacitance value and output.

[0009] Optionally, continuous monitoring of capacitor voltage includes: The voltage across the capacitor is continuously acquired using an analog-to-digital converter at a preset sampling frequency to obtain a capacitor voltage sampling sequence.

[0010] Optional, also includes: Determine whether the total detection time exceeds the preset safety threshold, or whether the capacitor voltage reaches the preset safety voltage limit. If so, the measurement process will be forcibly terminated.

[0011] Optional, also includes: Before the measurement begins, adjust the charging current supplied to the capacitor by the constant current source according to the capacitance range.

[0012] To address the aforementioned technical problems, the present invention also provides a capacitance adaptive measurement device based on measurement accuracy constraints, comprising: Memory, used to store computer programs; A processor is used to implement the steps of the above-described adaptive capacitance measurement method based on measurement accuracy constraints when executing the computer program.

[0013] To address the aforementioned technical problems, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the aforementioned capacitance adaptive measurement method based on measurement accuracy constraints.

[0014] This invention provides a capacitance adaptive measurement method based on measurement accuracy constraints. During the measurement process, a constant current source is controlled to charge the capacitor while continuously monitoring the capacitor voltage. Based on the continuously monitored changes in capacitor voltage, when the changes in capacitor voltage meet the minimum effective voltage change requirement, a capacitance estimate is calculated to obtain multiple capacitance estimates. It is then determined whether the relationship between these multiple capacitance estimates meets a preset stability condition. If it does, the final capacitance value is output; otherwise, data acquisition and calculation continue until the stability condition is met. This scheme determines the minimum effective voltage change based on system resolution and preset measurement accuracy, ensuring that the voltage changes involved in the capacitance calculation meet the effective resolution requirements of the measurement system, reducing the impact of factors such as analog-to-digital converter resolution and system noise on the capacitance calculation results. Simultaneously, by judging whether the capacitor under test has reached a stable state through the relationship between multiple capacitance estimates, the measurement error caused by fluctuations in capacitance estimates at different charging stages due to the capacitor's own electrochemical characteristics can be effectively reduced. The measurement ends and the capacitance value is output after the preset stability conditions are met. There is no need to use a fixed measurement time or a fixed cutoff voltage. The measurement process can be adaptively adjusted according to the actual measurement state, which reduces redundant sampling time while ensuring the accuracy of capacitance measurement and improving the measurement efficiency of capacitors with different capacitance ranges.

[0015] Furthermore, the capacitance adaptive measurement device and computer-readable storage medium based on measurement accuracy constraints provided by this invention have the same effect as above. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the prior art and embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A flowchart of a capacitance adaptive measurement method based on measurement accuracy constraints provided by the present invention; Figure 2 A flowchart illustrating a specific capacitance adaptive measurement method based on measurement accuracy constraints provided by the present invention; Figure 3 This is a schematic diagram of an adaptive voltage sampling window expansion provided by the present invention. Detailed Implementation

[0018] The core of this invention is to provide a capacitance adaptive measurement method, device, and medium based on measurement accuracy constraints.

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Capacitance measurement is widely used in electronic component testing, battery management systems, automated testing equipment, and precision instruments. The constant current charging method is widely applied to capacitance measurement due to its simple measurement principle and ease of implementation. Its basic principle is as follows: a constant current is used to charge the capacitor under test. The constant current source charging current is I. The charging time Δt corresponding to the change in capacitor voltage, and the change in capacitor voltage ΔV, are used to calculate the estimated capacitance C according to the following formula: ; Existing constant current charging methods calculate the capacitance of the capacitor under test after a fixed measurement time or a fixed cutoff voltage, failing to fully consider the resolution of the measurement system and the dynamic characteristics of the capacitor itself. On one hand, when the voltage change involved in the calculation is small, factors such as the resolution of the analog-to-digital converter and system noise significantly affect the capacitance calculation results. On the other hand, a fixed measurement time or fixed cutoff voltage makes it difficult to adaptively determine the effective amount of sampled data for different capacitance ranges and measurement accuracy requirements. For example, small-capacity capacitors charge quickly and reach the required accuracy soon; using a uniform charging time can easily lead to data acquisition redundancy. For larger capacitors, due to their slower charging speed, using a uniform charging time can easily result in voltage changes that do not meet the accuracy requirements. On the other hand, the actual capacitor is affected by the electrochemical characteristics of the capacitor during the charging process. When the capacitor has not reached a steady state, the voltage change rate corresponding to different charging stages may be different, resulting in different capacitor voltage changes obtained for the same charging time. This leads to fluctuations in the calculated capacity estimate. Since existing technologies usually perform single capacity calculations under fixed measurement time or fixed cutoff voltage conditions without judging whether the capacitor under test has entered a steady state, in order to ensure measurement accuracy, a longer measurement time or a higher cutoff voltage is often required, which generates redundant sampling, reduces measurement efficiency, and makes it difficult to balance the measurement accuracy and measurement efficiency of capacitors with different capacities.

[0021] To address the aforementioned technical problems, this invention provides a capacitance adaptive measurement method based on measurement accuracy constraints.

[0022] For details, please see Figure 1 , Figure 1 The flowchart illustrates a capacitance adaptive measurement method based on measurement accuracy constraints provided by this invention.

[0023] like Figure 1 As shown, the method includes: S11: Determine the system resolution and preset measurement accuracy; Specifically, during constant current charging measurement, the formula for calculating the estimated capacitance value is as follows: ; Where I is the charging current, Δ t Δ is the charging time corresponding to the voltage change. V This represents the change in capacitor voltage during the charging process. The formula for calculating the relative error ηC in capacitor measurement is: ; Where, Δ Vres The system resolution is the smallest voltage change that the measurement system can distinguish; Δ Ires Δ is the minimum change in charging current that the constant current source can provide. tresThis is the smallest time change that the measurement system can resolve. Because Δ Ires and Δ tres High accuracy can be guaranteed by a constant current source and system clock; therefore, the relative error ηC of capacitance measurement is mainly affected by the system resolution Δ. Vres Due to the influence of capacitance measurement, the relative error ηC can be approximated as: ; In actual measurements, the system's resolution is limited due to factors such as quantization errors in the analog-to-digital converter, system noise, and sampling errors, making it impossible for the measurement system to accurately distinguish very small voltage changes. Therefore, before measuring capacitance, it is necessary to determine the minimum voltage change that the measurement system can resolve, i.e., the system resolution Δ. Vres At the same time, the expected capacity measurement accuracy is determined based on actual application requirements, i.e., the preset measurement accuracy ε, as a constraint for subsequently determining effective measurement conditions.

[0024] S12: Determine the minimum effective voltage change based on the system resolution and preset measurement accuracy; Specifically, this embodiment does not use a fixed measurement time or a fixed cutoff voltage as the capacity calculation condition, but rather uses the current system resolution Δ Vres And a preset measurement accuracy ε, adaptively determining the minimum effective voltage change Δ to participate in capacity calculation. Vmin Before the measurement begins, a preset measurement accuracy ε is set according to actual needs. The relative error ηC of the capacitance measurement then needs to satisfy the following: ; Substituting into the formula for calculating the relative error ηC in capacitance measurement, we get: ; From the above inequality, we get: ; Therefore, the minimum effective voltage change Δ Vmin The calculation formula is: ; It should be understood that the above expression is only one example; in other implementations, the minimum effective voltage change Δ Vmin The system noise level, design margin, calibration error, and other factors can be combined to make corrections or determinations, but this invention does not limit these factors.

[0025] S13: Continuously detect the capacitor voltage, and calculate the capacitor capacity estimate based on the capacitor voltage change obtained from the continuous detection, when the capacitor voltage change meets the minimum effective voltage change requirement, so as to obtain multiple capacitor capacity estimates. Specifically, as an example, capacity estimation can be performed using continuous and non-overlapping measurement intervals. For instance, when starting constant current charging of the capacitor, the current voltage of the capacitor is used as the initial accumulation starting point, and the voltage signal across the capacitor under test is continuously acquired. When the cumulative change in capacitor voltage from the initial accumulation starting point reaches the minimum effective voltage change, the estimated capacitor capacity value is calculated. After completing the calculation of the current estimated capacitor capacity value, the current accumulation endpoint is updated to the new accumulation starting point, and the voltage of the capacitor under test continues to be acquired. When the cumulative change in capacitor voltage from the new accumulation starting point again reaches the minimum effective voltage change, a new estimated capacitor capacity value is calculated. Repeating this process can yield multiple estimated capacitor capacity values, and the acquisition sequence is as follows: 0~ΔVmin, ΔVmin~2ΔVmin, 2ΔVmin~3ΔVmin… …Calculate the estimated capacitance value for each measurement interval sequentially. As an example, the starting voltage of adjacent measurement intervals can also be adjusted according to measurement requirements; for example, it can be sequentially used… 0~ΔVmin, A~A+ΔVmin, B~B+ΔVmin…… Where B is greater than A. Each time a capacity estimate is calculated, the capacitor voltage change ΔV corresponding to the current cumulative interval and the corresponding charging time Δt can be statistically analyzed. Combined with the constant current source charging current I, the corresponding capacitor capacity estimate is calculated according to the constant current charging capacity calculation relationship. Furthermore, the number of multiple capacitor capacity estimates is not fixed and can be adjusted according to actual measurement needs, preset stability conditions, and measurement efficiency requirements. For example, after obtaining two consecutive capacitor capacity estimates, it can be determined whether the preset stability conditions are met.

[0026] S14: Determine whether the relationship between multiple estimated capacitance values ​​meets the preset stability condition; If so, output the final capacitance value; If not, continue to detect the capacitor voltage and calculate the estimated capacitance value until the preset stability condition is met.

[0027] Specifically, existing capacitance measurement methods typically calculate an estimated capacitance value based on the charging time and voltage change obtained from a single measurement after a preset measurement time has elapsed or the voltage of the capacitor under test has reached a preset cutoff voltage. Since the actual capacitor is affected by electrochemical characteristics during charging, its charging state may gradually change over time. Before reaching a stable state, the calculated capacitance results corresponding to different charging stages may fluctuate. Therefore, using a fixed measurement time or fixed cutoff voltage usually requires a large measurement margin to ensure the accuracy of the measurement results, which can easily lead to increased measurement time or redundant sampling. In this embodiment, the capacitance is not directly determined based on a single measurement result. Instead, the charging process is divided into multiple measurement stages, and multiple estimated capacitance values ​​corresponding to different charging stages are obtained. By analyzing the relationship between the changes in multiple estimated capacitance values, it can be determined whether the charging state of the capacitor under test tends to stabilize.

[0028] When the relationship between multiple capacitance estimates meets a preset stability condition, it indicates that the capacitance estimate of the capacitor under test has stabilized after multiple charging stages, and the final capacitance value is output. When the relationship between multiple capacitance estimates does not meet the preset stability condition, it indicates that the capacitor under test is still in a dynamic change phase, requiring continued acquisition of capacitor voltage and calculation of new capacitance estimates based on subsequent sampling data until the multiple capacitance estimates meet the preset stability condition. The preset stability condition characterizes whether the multiple capacitance estimates have stabilized. In practical applications, this can be determined based on the degree of change between adjacent capacitance estimates and the dispersion of multiple capacitance estimates. As an example, the stability condition can be determined by the relative rate of change between adjacent capacitance estimates being less than a preset threshold, or by the standard deviation or coefficient of variation of multiple capacitance estimates being less than a preset threshold.

[0029] Specifically, during the measurement process, a constant current source is controlled to charge the capacitor and the capacitor voltage is continuously monitored. Whenever the change in capacitor voltage reaches the minimum effective voltage change, the estimated value of the capacitor capacity is calculated. After obtaining multiple estimated values ​​of the capacitor capacity, it is determined whether the relationship between the multiple estimated values ​​of the capacitor capacity meets the preset stability condition. If it meets the condition, the final capacitor capacity value is output. If it does not meet the condition, the acquisition and calculation continue until the stability condition is met.

[0030] As can be seen, this embodiment determines the minimum effective voltage change based on system resolution and preset capacity measurement accuracy, ensuring that the voltage change involved in capacity calculation meets the effective resolution requirements of the measurement system, thus reducing the impact of factors such as analog-to-digital converter resolution and system noise on the capacity calculation results. Simultaneously, the relationship between multiple capacity estimates determines whether the capacitor under test has reached a stable state, effectively reducing measurement errors caused by fluctuations in capacity estimates at different charging stages due to the capacitor's own electrochemical characteristics. Measurement ends and the capacity value is output after the preset stability condition is met. Without using a fixed measurement time or fixed cutoff voltage, the measurement process can be adaptively adjusted according to the actual measurement state, ensuring the accuracy of capacity measurement while reducing redundant sampling time and improving the measurement efficiency of capacitors with different capacity ranges.

[0031] Based on the above embodiments, please refer to Figure 2 , Figure 2 The flowchart illustrates a specific capacitance adaptive measurement method based on measurement accuracy constraints provided by this invention.

[0032] As an optional embodiment, determining whether the relationship between multiple estimated capacitance values ​​satisfies a preset stability condition includes: The relative rate of change between adjacent estimated capacitance values ​​is less than a preset rate of change threshold. And / or, the standard deviation of multiple capacitance estimates is less than a preset standard deviation threshold; And / or, the coefficient of variation of multiple capacitance estimates is less than a preset coefficient of variation threshold.

[0033] Specifically, in this embodiment, a preset stability condition is used to determine whether multiple estimated capacitance values ​​have stabilized. When the capacitor under test is still in the initial charging stage or has not yet reached a stable state due to the electrochemical characteristics of the capacitor, the estimated capacitance values ​​obtained from each calculation usually fluctuate significantly. As the charging process continues, the differences between multiple estimated capacitance values ​​gradually decrease. When the relationship between the changes in multiple estimated capacitance values ​​meets the preset stability condition, the current measurement result can be considered to have reached the expected level of stability, thereby outputting the final capacitance value. The preset stability condition can be set according to the required measurement accuracy.

[0034] As an example, suppose the continuously obtained capacitance estimates are: ; in, The number of estimated capacitance values ​​used in the stability assessment, and .

[0035] When the relative rate of change between two adjacent capacitance estimates is less than a preset rate of change threshold is used as the preset stability condition, the relative rate of change is used as a stability index, and the calculation formula is as follows: ; in, That is, we get: ; common A relative rate of change is calculated, and then it is determined whether all of the above relative rates of change satisfy the following: ; in, The preset rate of change threshold is used to determine that when the relative rate of change between all adjacent capacity estimates is less than the preset rate of change threshold, the multiple capacity estimates have become stable, and the stability index meets the preset stability condition.

[0036] When the standard deviation of multiple capacitance estimates is less than a preset standard deviation threshold is used as a preset stability condition, the standard deviation is used as a stability index. First, the average value μ of multiple capacitance estimates is calculated: ; Then calculate the standard deviation: ; in, If the following conditions are met: ; in, If a preset standard deviation threshold is set, it is considered that the dispersion among multiple estimated capacitance values ​​is small, and the stability index can be determined to meet the preset stability condition.

[0037] When the coefficient of variation of multiple estimated capacitance values ​​is less than a preset coefficient of variation threshold as a preset stability condition, the coefficient of variation is used as a stability index, calculated based on the mean μ and standard deviation. Then, calculate the coefficient of variation: ; If the following conditions are met: ; in, If a preset coefficient of variation threshold is set, it is considered that there is good consistency among multiple estimated capacitance values, and the stability index can be determined to meet the preset stability condition.

[0038] It should be noted that the above-mentioned stability judgment methods can be used individually or in combination. For example, when the relative rate of change between adjacent capacitance estimates is less than a preset rate of change threshold and the standard deviation of multiple capacitance estimates is less than a preset standard deviation threshold, the preset stability condition can be determined to be met, thereby further improving the reliability of the stability judgment; or, depending on the actual measurement requirements, only one of the judgment methods can be used, and this application does not limit this.

[0039] As can be seen, this embodiment uses one or more of the relative rate of change, standard deviation and coefficient of variation as preset stability conditions, which can objectively reflect the convergence of multiple capacitance estimates, improve the accuracy of stability judgment, and thus improve the reliability of capacitance measurement results.

[0040] As an optional embodiment, the system resolution is determined based on the reference voltage of the measurement system and the effective noise-free resolution bits or the effective resolution bits.

[0041] Specifically, system resolution characterizes the smallest voltage change that a measurement system can resolve. Higher system resolution means a smaller detectable voltage change and less measurement error introduced by voltage quantization during capacitance measurement. Conversely, lower system resolution requires a larger voltage change to meet the preset measurement accuracy requirements. System resolution can be determined based on the reference voltage and the effective noise-free resolution bits of the measurement system, and its calculation formula can be expressed as: ; in, This represents the minimum resolvable voltage change corresponding to the system resolution. The reference voltage of the measurement system is represented by ; N represents the effective noise-free resolution bits of the measurement system. Alternatively, the effective resolution bits can be replaced with the effective noise-free resolution bits to determine the system resolution.

[0042] As an example, the measurement system can use an analog-to-digital converter (ADC) to acquire the voltage signal across the capacitor under test. In this case, the system resolution corresponds to the smallest voltage change Δ that the ADC can resolve. V ADC , can be represented as: ; in, N is the reference voltage of the analog-to-digital converter, and N1 is the effective noise-free resolution bit depth of the analog-to-digital converter.

[0043] As can be seen, this embodiment determines the system resolution based on the reference voltage and effective noise-free resolution bits of the measurement system, so that the system resolution can truly reflect the actual voltage resolution capability of the measurement system, providing a basis for determining the minimum effective voltage change, thereby enabling subsequent capacity measurement to meet the preset measurement accuracy requirements and improving the accuracy and reliability of the capacity measurement results.

[0044] As an optional embodiment, it also includes: The system noise voltage of the measurement system is obtained, and the minimum effective voltage change is superimposed and corrected by combining the system noise voltage.

[0045] Specifically, in actual measurement processes, besides the measurement system resolution, factors such as analog front-end circuit noise and analog-to-digital converter noise can cause fluctuations in the acquired voltage signal. Therefore, determining the capacity calculation range solely based on the minimum effective voltage change may result in the effective voltage change being comparable to the noise amplitude, thus affecting the stability of the capacity calculation results. Therefore, this embodiment further acquires the system noise voltage of the measurement system and uses this system noise voltage to correct the minimum effective voltage change, thereby obtaining the minimum effective voltage change actually used for capacity calculation.

[0046] As an example, the correction can be made in the following way: ; in, The minimum effective voltage change; The system noise voltage of the measurement system is denoted as m; m is a preset safety factor, the value of which can be set according to the noise level of the measurement system, and m > 0. This is the corrected minimum effective voltage change.

[0047] As can be seen, this embodiment further considers the influence of measurement system noise on the basis of the minimum effective voltage change. By correcting the minimum effective voltage change, the actual voltage change involved in the capacity calculation is higher than the system noise level, which reduces the fluctuation of the capacity estimate caused by noise and improves the stability and reliability of the capacity measurement results.

[0048] As an optional embodiment, the final capacitance value is output, including: The latest calculated capacitance estimate that meets the preset stability conditions is determined as the final capacitance value and output. Alternatively, the average value of a set of estimated capacitance values ​​that meet the preset stability conditions can be determined as the final capacitance value and output. Alternatively, the median of a set of estimated capacitance values ​​that meet the preset stability conditions can be determined as the final capacitance value and output.

[0049] Specifically, once multiple capacitance estimates meet preset stability conditions, different final capacitance value determination methods can be selected based on different application scenarios. For example, the latest calculated capacitance estimate that meets the preset stability conditions can be determined as the final capacitance value. Since the latest capacitance estimate corresponds to the most recent charging state of the capacitor under test, once the system determines that the capacitor has entered a stable state, this capacitance estimate can directly reflect the current measurement result without additional data processing, making it suitable for applications requiring high measurement response speed. Alternatively, the average of a set of capacitance estimates that meet the preset stability conditions can be determined as the final capacitance value. Since the average can reduce the impact of random noise and accidental errors on single capacitance estimation results, it can further improve the stability and accuracy of the final measurement result, making it suitable for applications requiring high measurement accuracy. Finally, the median of a set of capacitance estimates that meet the preset stability conditions can be determined as the final capacitance value. Since the median is less affected by individual abnormal capacitance estimates, using the median can improve the robustness of the final measurement result when there is occasional noise interference or abnormal sampling data during the measurement process, avoiding large deviations caused by outliers.

[0050] As can be seen, this embodiment provides multiple methods for determining the final capacitance value. The output strategy can be flexibly selected according to different requirements such as measurement response speed, measurement accuracy, and resistance to abnormal data. While ensuring measurement reliability, it improves the applicability and engineering application flexibility of this method.

[0051] As an optional embodiment, continuous detection of capacitor voltage includes: The voltage across the capacitor is continuously acquired using an analog-to-digital converter at a preset sampling frequency to obtain a capacitor voltage sampling sequence.

[0052] For details, please see Figure 3 , Figure 3 This is a schematic diagram illustrating an adaptive voltage sampling window expansion method provided by the present invention. (See diagram below.) Figure 3 As shown, the voltage across the capacitor under test is continuously acquired via an analog-to-digital converter at a preset sampling frequency to obtain a capacitor voltage sampling sequence. The sampling rate of the analog-to-digital converter can be set according to actual needs, and this embodiment does not impose any restrictions on it.

[0053] Specifically, during the charging process of the capacitor under test by the constant current source, the controller controls the analog-to-digital converter to continuously sample the voltage across the capacitor under test according to a preset sampling frequency, and sequentially obtains multiple voltage sample values ​​to form a capacitor voltage sampling sequence: ; Calculate the change in capacitor voltage Δ V1 = Vn - V1 Then, it is determined whether the change in capacitor voltage reaches the minimum effective voltage change Δ. Vmin If Δ V1 <Δ Vmin This indicates that the voltage change within the current sampling window is insufficient to meet the preset measurement accuracy requirements. Therefore, capacity calculation is not performed, and new voltage samples are collected instead. For example, to obtain: Vn+1、 Vn+2……Vn+a , a The value is a positive integer, and the change in capacitor voltage Δ is recalculated. V2 = Vn + a - V1 If Δ V2≥Δ Vmin This indicates that the current sampling interval has met the minimum effective voltage change requirement. At this point, the charging time Δt2 corresponding to this sampling window is calculated, and the estimated capacitance value is calculated based on the constant current charging principle. : ; After completing the first capacitance calculation, the next sampling window begins. For example, if continuous and non-overlapping measurement intervals are used, the next sampling window would be: Vn+a, Vn+a+1, ..., V2n+2a The corresponding change in capacitor voltage Δ V3 = V2n + 2a-Vn+a The corresponding charging time is Δt3. Based on the constant current charging principle, the estimated value of the corresponding capacitor capacity is calculated. : ; Furthermore, the starting voltage of adjacent measurement intervals can also be adjusted according to measurement requirements, and this embodiment does not impose any restrictions on this.

[0054] As can be seen, this embodiment continuously acquires capacitor voltage through an analog-to-digital converter and dynamically adjusts the sampling window involved in capacity calculation based on the cumulative voltage change, so that the voltage change involved in capacity calculation can meet the measurement accuracy requirements, avoiding the problem of insufficient voltage change or redundant sampling data caused by fixed sampling time, thus improving the accuracy and efficiency of capacitor capacity measurement.

[0055] As an optional embodiment, it also includes: Determine whether the total detection time exceeds the preset safety threshold, or whether the capacitor voltage reaches the preset safety voltage limit. If so, the measurement process will be forcibly terminated.

[0056] Specifically, to avoid measurement safety issues caused by excessively long measurement periods due to capacitor malfunctions, measurement system failures, or continuously rising capacitor charging voltage, a safety protection mechanism can be added during capacity measurement. While measuring capacitance, the controller continuously records the total detection time from the start of the measurement to the current moment and monitors the voltage across the capacitor in real time. When the total detection time exceeds a preset safety threshold, or the capacitor voltage reaches a preset upper safety voltage limit, the controller immediately stops constant current charging and forcibly terminates the capacity measurement process. The safety threshold and upper safety voltage limit can be set according to the rated parameters of the capacitor under test, the performance of the measurement system, or actual application requirements; this application does not impose any limitations on these settings.

[0057] As can be seen, this embodiment, by setting a dual safety protection mechanism for total detection time and capacitor voltage, can avoid the measurement process from continuing indefinitely or the capacitor from overcharging under abnormal conditions, thereby improving the safety and reliability of the capacitance measurement process.

[0058] As an optional embodiment, it also includes: Before the measurement begins, adjust the charging current supplied to the capacitor by the constant current source according to the capacitance range.

[0059] Specifically, when the capacitance to be measured is small, a smaller charging current can be used to avoid the capacitor voltage rising too quickly and reducing the measurement accuracy; when the capacitance to be measured is large, a larger charging current can be used to shorten the charging time required to reach the minimum effective voltage change and improve the measurement efficiency.

[0060] One implementation method is to determine the charging current output of the constant current source based on the nominal capacitance of the capacitor under test, historical measurement results, user input parameters, or a preset capacitance range. This application does not limit the specific method of adjusting the charging current, as long as the output current of the constant current source can be adjusted according to the capacitance range of the capacitor under test.

[0061] As can be seen, this embodiment adaptively adjusts the constant current charging current according to the capacitance range of the capacitor under test, so that capacitors under test with different capacitance ranges can complete the capacitance measurement at a suitable charging speed. This ensures both measurement accuracy and measurement efficiency, and improves the applicability to capacitors with different capacitances.

[0062] To address the aforementioned technical problems, the present invention also provides a capacitance adaptive measurement device based on measurement accuracy constraints, comprising: Memory, used to store computer programs; A processor is used to implement the steps of the above-described adaptive capacitance measurement method based on measurement accuracy constraints when executing a computer program.

[0063] For an introduction to the capacitance adaptive measurement device based on measurement accuracy constraints provided by the present invention, please refer to the embodiments of the capacitance adaptive measurement method based on measurement accuracy constraints described above. The present invention will not be repeated here.

[0064] To address the aforementioned technical problems, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the aforementioned capacitance adaptive measurement method based on measurement accuracy constraints.

[0065] For a description of the computer-readable storage medium provided by this invention, please refer to the above-described embodiments of the capacitance adaptive measurement method based on measurement accuracy constraints; further details of this invention will not be repeated here.

[0066] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0067] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

Claims

1. A capacitance adaptive measurement method based on measurement accuracy constraints, characterized in that, include: Determine the system resolution and preset measurement accuracy; The minimum effective voltage change is determined based on the system resolution and the preset measurement accuracy. The capacitor voltage is continuously monitored, and based on the change in capacitor voltage obtained from the continuous monitoring, when the change in capacitor voltage meets the minimum effective voltage change requirement, a capacitor capacity estimate is calculated to obtain multiple capacitor capacity estimates. Determine whether the relationship between multiple estimated capacitance values ​​meets the preset stability condition; If so, output the final capacitance value; If not, continue to detect the capacitor voltage and calculate the estimated capacitor capacity until the preset stability condition is met.

2. The capacitance adaptive measurement method based on measurement accuracy constraints as described in claim 1, characterized in that, Determine whether the relationship between multiple estimated capacitance values ​​meets preset stability conditions, including: The relative rate of change between adjacent estimated capacitance values ​​is less than a preset rate of change threshold. And / or, the standard deviation of multiple capacitance estimates is less than a preset standard deviation threshold; And / or, the coefficient of variation of multiple capacitance estimates is less than a preset coefficient of variation threshold.

3. The capacitance adaptive measurement method based on measurement accuracy constraints as described in claim 1, characterized in that, The system resolution is determined based on the reference voltage of the measurement system and the effective noise-free resolution bits or the effective resolution bits.

4. The capacitance adaptive measurement method based on measurement accuracy constraints as described in claim 1, characterized in that, Also includes: The system noise voltage of the measurement system is obtained, and the minimum effective voltage change is superimposed and corrected based on the system noise voltage.

5. The capacitance adaptive measurement method based on measurement accuracy constraints as described in claim 1, characterized in that, The final capacitance value is output, including: The latest calculated capacitance estimate that meets the preset stability condition is determined as the final capacitance value and output. Alternatively, the average value of a set of estimated capacitance values ​​that meet the preset stability conditions can be determined as the final capacitance value and output. Alternatively, the median of a set of estimated capacitance values ​​that meet the preset stability conditions can be determined as the final capacitance value and output.

6. The capacitance adaptive measurement method based on measurement accuracy constraints as described in claim 1, characterized in that, Continuous monitoring of capacitor voltage, including: The voltage across the capacitor is continuously acquired using an analog-to-digital converter at a preset sampling frequency to obtain a capacitor voltage sampling sequence.

7. The capacitance adaptive measurement method based on measurement accuracy constraints as described in claim 1, characterized in that, Also includes: Determine whether the total detection time exceeds the preset safety threshold, or whether the capacitor voltage reaches the preset safety voltage limit. If so, the measurement process will be forcibly terminated.

8. The capacitance adaptive measurement method based on measurement accuracy constraints as described in claim 1, characterized in that, Also includes: Before the measurement begins, adjust the charging current supplied to the capacitor by the constant current source according to the capacitance range.

9. A capacitance adaptive measurement device based on measurement accuracy constraints, characterized in that, include: Memory, used to store computer programs; A processor, configured to implement the steps of the capacitance adaptive measurement method based on measurement accuracy constraints as described in any one of claims 1 to 8 when executing the computer program.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the capacitance adaptive measurement method based on measurement accuracy constraints as described in any one of claims 1 to 8.

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