Film capacitor life prediction method and device, electronic equipment and storage medium

Abstract

The invention belongs to the technical field of aging test of electronic components, and particularly discloses a film capacitor life prediction method and device, electronic equipment and a storage medium. The method comprises the following steps: acquiring voltage information of two ends of a to-be-tested thin-film capacitor in a current prediction period under an aging test working condition; extracting a voltage direct current component and a voltage harmonic component in the voltage information, and determining an aging acceleration factor based on the voltage harmonic component; determining the aging rate of the to-be-tested thin film capacitor in the current prediction period based on the voltage direct current component, the hot spot temperature in the current prediction period and the aging acceleration factor; and determining the service life of the to-be-tested thin film capacitor according to the total duration corresponding to the current prediction period under the condition that the aging rate meets the preset life end threshold condition. According to the invention, automatic prediction of the service life of the thin-film capacitor is realized without manual participation, and the accuracy and efficiency of prediction of the service life of the thin-film capacitor can be greatly improved.

Description

Technical Field

[0001] The present application belongs to the technical field of electronic component aging testing, and more specifically, relates to a method, device, electronic device and storage medium for predicting the life of a film capacitor. Background Art

[0002] Metal film capacitors have the self-healing property that their nanometer-thick metal electrodes can recover their insulation properties after evaporation loss under the heat of large currents formed during the penetration of weak electrical points in the dielectric. This property gives metal film capacitors high reliability and large capacity, and they are widely used in engineering fields such as ultra-high voltage AC and DC transmission and flexible DC transmission systems. In actual operation, the self-healing process of the metal film occurs continuously, causing the loss of metal electrodes, which in turn leads to a decrease in the capacity of the capacitor until the end of its life, which will eventually affect the operation of the engineering system in which the capacitor is located. Therefore, in order to ensure the safe and reliable operation of the system in which the film capacitor is located, it is very necessary to explore the life prediction method of the film capacitor.

[0003] At present, the traditional film capacitor life prediction research mainly adopts the method of manual experience prediction, that is, the change of capacitance value is checked regularly according to the specified time, so as to judge and estimate the life of film capacitors in this process. However, due to the subjectivity and uncertainty of manual judgment itself, it is easy to cause huge deviations in the final prediction results, resulting in low accuracy of film capacitor life prediction.

[0004] Therefore, how to better predict the life of metal film capacitors has become a technical problem that needs to be solved urgently in the industry. Summary of the invention

[0005] In view of the defects of the prior art, the purpose of this application is to better realize the life prediction of metal film capacitors, aiming to solve the problem of low accuracy of traditional manual methods for predicting the life of film capacitors.

[0006] To achieve the above objectives, in a first aspect, the present application provides a method for predicting the life of a film capacitor, comprising:

[0007] Obtaining voltage information at both ends of the film capacitor to be tested during the current prediction cycle period under aging test conditions;

[0008] extracting a voltage DC component and a voltage harmonic component from the voltage information, and determining an aging acceleration factor based on the voltage harmonic component;

[0009] Determine the aging rate of the film capacitor to be tested in the current prediction cycle period based on the voltage DC component, the hot spot temperature in the current prediction cycle period and the aging acceleration factor; the hot spot temperature in the current prediction cycle period is determined based on the equivalent series resistance and the ambient temperature in the current prediction cycle period;

[0010] When it is determined that the aging rate meets a preset life end threshold condition, the life of the thin film capacitor to be tested is determined according to the total duration corresponding to the current prediction cycle period.

[0011] Optionally, determining the aging rate of the thin film capacitor to be tested in the current prediction cycle period based on the voltage DC component, the hot spot temperature in the current prediction cycle period and the aging acceleration factor includes:

[0012] Determine the change in the hot spot temperature of the thin film capacitor to be tested during the current prediction cycle period based on the hot spot temperature during the current prediction cycle period and the hot spot temperature of the thin film capacitor to be tested before the aging test;

[0013] The rated aging rate of the film capacitor to be tested is obtained, and based on the rated aging rate, the hot spot temperature change, the voltage DC component and the aging acceleration factor, the aging rate of the film capacitor to be tested in the current prediction cycle period is determined.

[0014] Optionally, before determining the aging rate of the thin film capacitor to be tested in the current prediction cycle period based on the voltage DC component, the hot spot temperature in the current prediction cycle period and the aging acceleration factor, the method further includes:

[0015] Determine the equivalent series resistance of the thin film capacitor to be tested during the current prediction cycle period;

[0016] Based on the equivalent series resistance of the current prediction cycle period and the current information of both ends of the thin film capacitor to be tested in the current prediction cycle period, the heating power of the thin film capacitor to be tested is determined to calculate the temperature rise of the thin film capacitor to be tested in the current prediction cycle period;

[0017] The hot spot temperature of the thin film capacitor to be tested in the current prediction cycle period is determined according to the temperature rise and the ambient temperature.

[0018] Optionally, the determining the equivalent series resistance of the thin film capacitor to be tested in the current prediction cycle period includes:

[0019] Calculating an initial value of an equivalent series resistance of the thin film capacitor to be tested by using an operating frequency and a capacitance value of the thin film capacitor to be tested;

[0020] The equivalent series resistance of the thin film capacitor to be tested in the current prediction cycle period is determined based on the voltage DC component, the initial value of the equivalent series resistance of the thin film capacitor to be tested, the hot spot temperature in the previous prediction cycle period and the aging acceleration factor.

[0021] Optionally, after determining the aging rate of the thin film capacitor to be tested in the current prediction cycle period based on the voltage DC component, the hot spot temperature in the current prediction cycle period and the aging acceleration factor, the method further includes:

[0022] When it is determined that the aging rate does not meet the preset life end threshold condition, obtaining voltage information of both ends of the thin film capacitor to be tested in the next prediction cycle period;

[0023] Calculating the aging rate of the film capacitor to be tested in the next prediction cycle period by using the voltage information in the next prediction cycle period;

[0024] When it is determined that the aging rate of the next prediction cycle period meets the preset life end threshold condition, the life of the thin film capacitor to be tested is determined according to the total time length corresponding to the next prediction cycle period.

[0025] Optionally, determining the aging acceleration factor based on the voltage harmonic component includes:

[0026] Based on the voltage harmonic components, determining a first amplitude, a first effective value, and a first peak value of the fundamental voltage component, and a second amplitude, a second effective value, and a second peak value of each voltage harmonic component;

[0027] Obtaining a first aging acceleration factor according to a ratio of the second peak value to the first peak value;

[0028] Obtaining a second aging acceleration factor according to a ratio of the second effective value to the first effective value;

[0029] determining a third aging acceleration factor based on a ratio of the second amplitude to the first amplitude;

[0030] The aging acceleration factor includes at least one of the first aging acceleration factor, the second aging acceleration factor, and the third aging acceleration factor.

[0031] In a second aspect, the present application provides a device for predicting the life of a thin film capacitor, comprising:

[0032] An acquisition module is used to obtain voltage information of both ends of the film capacitor to be tested in the current prediction cycle period under the aging test condition;

[0033] A first processing module, configured to extract a voltage DC component and a voltage harmonic component from the voltage information, and determine an aging acceleration factor based on the voltage harmonic component;

[0034] A second processing module is used to determine the aging rate of the film capacitor to be tested in the current prediction cycle period based on the voltage DC component, the hot spot temperature in the current prediction cycle period and the aging acceleration factor; the hot spot temperature in the current prediction cycle period is determined based on the equivalent series resistance and the ambient temperature in the current prediction cycle period;

[0035] The prediction module is used to predict the life of the thin film capacitor to be tested based on the total duration corresponding to the current prediction cycle period when it is determined that the aging rate meets a preset life end threshold condition.

[0036] In a third aspect, the present application provides an electronic device comprising: at least one memory for storing programs; and at least one processor for executing the programs stored in the memory. When the program stored in the memory is executed, the processor is used to execute the method described in the first aspect or any possible implementation of the first aspect.

[0037] In a fourth aspect, the present application provides a computer-readable storage medium, which stores a computer program. When the computer program runs on a processor, the processor executes the method described in the first aspect or any possible implementation of the first aspect.

[0038] In a fifth aspect, the present application provides a computer program product. When the computer program product runs on a processor, the processor executes the method described in the first aspect or any possible implementation of the first aspect.

[0039] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the prior art:

[0040] The present application provides a method, device, electronic device and storage medium for predicting the life of a film capacitor. By combining the influence of the aging process of the film capacitor on its life, a periodic prediction method is adopted for the life of the film capacitor. The voltage information at both ends of the film capacitor to be tested in the current prediction period under the aging test condition is used to extract the voltage DC component and voltage harmonic component. By exploring the multi-dimensional influencing factors affecting the aging of the film capacitor, the influence of the voltage harmonic component on the aging of the film capacitor is considered, and an aging acceleration factor is constructed using the extracted voltage harmonic component. Then, the aforementioned voltage DC component, the hot spot temperature in the current prediction period and the aging acceleration factor are used to determine the aging rate of the film capacitor to be tested in the current prediction period, so as to judge the current aging degree of the film capacitor, thereby realizing automatic prediction of the life of the film capacitor without human intervention, which can greatly improve the accuracy and efficiency of the film capacitor life prediction. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 One of the flow charts of the method for predicting the life of a film capacitor provided in an embodiment of the present application;

[0042] Figure 2 Schematic diagram 2 of the flow chart of the method for predicting the life of a film capacitor provided in an embodiment of the present application;

[0043] Figure 3 is a schematic diagram of the structure of a thin film capacitor life prediction device provided in an embodiment of the present application;

[0044] Figure 4 It is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0046] The terms "first" and "second" and the like in the specification and claims herein are used to distinguish different objects rather than to describe a specific order of the objects. For example, the first aging acceleration factor and the second aging acceleration factor are used to distinguish aging acceleration factors under different factor coefficients rather than to describe a specific order of the aging acceleration factors; for another example, the first amplitude and the second amplitude are used to distinguish the amplitudes of different harmonic components rather than to describe a specific order of the amplitudes.

[0047] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0048] In the description of the embodiments of the present application, unless otherwise specified, the meaning of "plurality" refers to two or more than two. For example, a plurality of computer instructions refers to two or more than two computer instructions.

[0049] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0050] Figure 1 FIG. 1 is one of the flow charts of the method for predicting the life of a film capacitor provided in an embodiment of the present application. Figure 1 As shown, including:

[0051] Step S1, obtaining voltage information of both ends of the film capacitor to be tested in the current prediction cycle period under the aging test condition;

[0052] Step S2, extracting a voltage DC component and a voltage harmonic component from the voltage information, and determining an aging acceleration factor based on the voltage harmonic component;

[0053] Step S3, determining the aging rate of the film capacitor to be tested in the current prediction cycle period based on the DC component of the voltage, the hot spot temperature in the current prediction cycle period and the aging acceleration factor; the hot spot temperature in the current prediction cycle period is determined based on the equivalent series resistance and the ambient temperature in the current prediction cycle period;

[0054] Step S4, when it is determined that the aging rate meets the preset life end threshold condition, the life of the film capacitor to be tested is determined according to the total time length corresponding to the current prediction cycle period.

[0055] Specifically, the prediction cycle period described in the embodiment of the present application refers to the prediction cycle period preset under the aging test condition, which can be recorded as Δt and can be set according to actual needs, such as a value of 0.5 hours, or 1 hour, etc.

[0056] In the embodiment of the present application, an aging analysis of the film capacitor is performed under AC voltage conditions. Therefore, it can be understood that the voltage information described in the embodiment of the present application refers to AC voltage information, and the DC component and voltage harmonic component of the voltage information can be extracted by decoupling.

[0057] The aging acceleration factor described in the embodiment of the present application refers to a factor that can characterize the factors that affect the accelerated aging of the thin film capacitor, which can be specifically determined by analyzing the relationship between voltage information and the aging of the thin film capacitor and based on the voltage harmonic components in the voltage information.

[0058] The hot spot temperature of the current prediction cycle period described in the embodiment of the present application refers to the temperature of the hottest spot inside the film capacitor to be tested when the aging test process reaches the current prediction cycle period, which can be recorded as T hs Specifically, it can be obtained by analyzing and calculating the equivalent series resistance (ESR) and ambient temperature during the current forecast period.

[0059] The aging rate described in the embodiment of the present application refers to the rate of capacitance loss of the film capacitor to be tested within a cycle period, which can be recorded as V.

[0060] The preset end-of-life threshold condition described in the embodiment of the present application is used to determine whether the aging degree of the film capacitor caused by the aging rate exceeds its own life.

[0061] It can be understood that the total duration T corresponding to the current prediction cycle period is T=NΔt, where N represents the cycle sequence number corresponding to the current prediction cycle period.

[0062] More specifically, in an embodiment of the present application, in step S1, a signal acquisition device may be used to collect and obtain voltage information across the thin film capacitor to be tested in the current prediction cycle period under aging test conditions.

[0063] In an embodiment of the present application, in step S2, the voltage information of the current prediction cycle period obtained in step S1 can be subjected to fast Fourier transform (FFT) processing, and the voltage DC component and voltage harmonic component in the voltage information can be extracted from the FFT transformation result. By exploring the influence relationship between the harmonic component of the voltage across the film capacitor and the aging of the film capacitor, the aging acceleration factor can be determined based on the fundamental component and multiple harmonic components in the voltage harmonic component, so as to prepare for the subsequent calculation of the aging rate of the film capacitor to be tested.

[0064] Based on the content of the above embodiment, as an optional embodiment, determining the aging acceleration factor based on the voltage harmonic component includes:

[0065] Based on the voltage harmonic components, determining a first amplitude, a first effective value, and a first peak value of the fundamental voltage component, and a second amplitude, a second effective value, and a second peak value of each voltage harmonic component;

[0066] Obtaining a first aging acceleration factor according to a ratio of the second peak value to the first peak value;

[0067] Obtaining a second aging acceleration factor according to a ratio of the second effective value to the first effective value;

[0068] determining a third aging acceleration factor based on a ratio of the second amplitude to the first amplitude;

[0069] The aging acceleration factor includes at least one of a first aging acceleration factor, a second aging acceleration factor, and a third aging acceleration factor.

[0070] Specifically, in an embodiment of the present application, after the voltage information of the current prediction cycle period is subjected to FFT transformation processing to extract the voltage harmonic components in the voltage information, the first harmonic component (ie, the fundamental voltage component) and other voltage harmonic components can be further determined.

[0071] For the fundamental voltage component, the power frequency voltage and the effective value and peak value of the fundamental voltage component can be calculated, that is, the first amplitude U1 and the first effective value U 1rms and the first peak U 1p .

[0072] For each voltage harmonic component including the fundamental voltage component, the amplitude corresponding to each voltage harmonic component and the overall effective value and peak value of each voltage harmonic component can be further calculated to obtain the second amplitude U j , the second effective value U rms and the second peak U p , where j = 1, 2, …, M, which represents the secondary of each voltage harmonic component.

[0073] Further, in the embodiment of the present application, according to the second peak value U p With the first peak U 1p The ratio of the first aging acceleration factor K p ,Right now It can reflect the peak factor of each voltage harmonic component.

[0074] In the embodiment of the present application, according to the second effective value U rms With the first effective value U 1rms The ratio of the second aging acceleration factor K rms ,Right now It can reflect the effective value coefficient of each voltage harmonic component.

[0075] In the embodiment of the present application, based on the second amplitude U j The ratio of the first amplitude U1 determines the third aging acceleration factor K f , the specific calculation formula of this process is as follows:

[0076]

[0077] This formula can reflect the waveform coefficient of each voltage harmonic component.

[0078] In the embodiment of the present application, the aging acceleration factor includes a first aging acceleration factor K p , the second aging acceleration factor K rms and the third aging acceleration factor K f At least one of the above, that is, the aging acceleration factor specifically includes the first aging acceleration factor K p , the second aging acceleration factor K rms and the third aging acceleration factor K f One of the above, or any two of the three types of aging acceleration factors, or all three types of aging acceleration factors.

[0079] Optionally, in the embodiment of the present application, the aging acceleration factor used specifically includes a first aging acceleration factor K p , the second aging acceleration factor K rms and the third aging acceleration factor K f Three items can make the prediction of the final film capacitor life best.

[0080] The method of the embodiment of the present application explores the multi-dimensional influencing factors that affect the aging of film capacitors, considers the influence of voltage harmonic components on the aging of film capacitors, and uses each voltage harmonic component to construct an aging acceleration factor. In this way, the aging influencing factors based on voltage harmonic components are introduced into the prediction process of the life of film capacitors, which is beneficial to improving the accuracy and precision of the prediction of the life of film capacitors.

[0081] Further, in the embodiment of the present application, in step S3, the equivalent series resistance and the ambient temperature of the current prediction period can be first obtained, and then the hot spot temperature of the current prediction period can be determined. Then, based on the voltage DC component of the voltage information calculated above, the hot spot temperature of the current prediction period and the aging acceleration factor, combined with the multi-dimensional parameters affecting the aging process of the film capacitor, the aging rate V of the film capacitor to be tested in the current prediction period is calculated. t .

[0082] In the embodiment of the present application, the aging rate V of the current prediction cycle period is t The preset end-of-life threshold condition that needs to be met can be expressed as the following inequality:

[0083]

[0084] In the formula, t N=NΔt, N = 1, 2, 3, .... Wherein, N represents the cycle sequence number corresponding to the current prediction cycle period.

[0085] It can be understood that the above expression of the preset end-of-life threshold condition is used to indicate that the accumulated aging degree of the film capacitor has exceeded its own life.

[0086] Furthermore, in an embodiment of the present application, in step S4, when it is determined that the aging rate of the current prediction cycle period satisfies the preset life end threshold condition, that is, when the above inequality is satisfied, it means that the accumulated aging degree of the film capacitor has exceeded its own life. At this time, the total duration corresponding to the current prediction cycle period can be calculated and used as the predicted life of the film capacitor to be tested, that is, the predicted life of the film capacitor is L=NΔt.

[0087] The life prediction method of the film capacitor in the embodiment of the present application adopts a periodic prediction method for the life of the film capacitor by combining the influence of the aging process of the film capacitor on its life, and uses the voltage information at both ends of the film capacitor to be tested in the current prediction period under the aging test conditions to extract the voltage DC component and voltage harmonic component, and by exploring the multi-dimensional influencing factors affecting the aging of the film capacitor, the influence of the voltage harmonic component on the aging of the film capacitor is considered, and the aging acceleration factor is constructed using the extracted voltage harmonic component, and then the aging rate of the film capacitor to be tested in the current prediction period is determined using the aforementioned voltage DC component, the hot spot temperature in the current prediction period and the aging acceleration factor, so as to judge the current aging degree of the film capacitor, thereby realizing automatic prediction of the life of the film capacitor without human intervention, which can greatly improve the accuracy and efficiency of the film capacitor life prediction.

[0088] Based on the content of the above embodiment, as an optional embodiment, before determining the aging rate of the film capacitor to be tested in the current prediction cycle period based on the voltage DC component, the hot spot temperature in the current prediction cycle period and the aging acceleration factor, the method further includes:

[0089] Determine the equivalent series resistance of the film capacitor to be tested during the current prediction cycle period;

[0090] Based on the equivalent series resistance of the current prediction cycle period and the current information at both ends of the thin film capacitor to be tested in the current prediction cycle period, the heating power of the thin film capacitor to be tested is determined to calculate the temperature rise of the thin film capacitor to be tested in the current prediction cycle period;

[0091] According to the temperature rise and the ambient temperature, the hot spot temperature of the film capacitor to be tested in the current prediction cycle period is determined.

[0092] Specifically, in an embodiment of the present application, before determining the aging rate of the film capacitor to be tested in the current prediction cycle period based on the voltage DC component, the hot spot temperature in the current prediction cycle period, and the aging acceleration factor, it is first necessary to determine the ESR value of the film capacitor to be tested in the current prediction cycle period. Here, the ESR value of the film capacitor to be tested in the current prediction cycle period can be calculated according to the existing formula ESR = tanδ / 2πfC, where tanδ represents the loss tangent value, which is the loss caused by the electrolyte and electrode structure inside the capacitor; f represents the operating frequency of the film capacitor to be tested; and C represents the capacitance value of the film capacitor to be tested.

[0093] Optionally, in an embodiment of the present application, the above-mentioned ESR calculation method may be improved by introducing an aging acceleration factor, and the improved ESR calculation method may be used to calculate the hot spot temperature in the subsequent current prediction cycle period.

[0094] Based on the content of the above embodiment, as an optional embodiment, determining the equivalent series resistance of the thin film capacitor to be tested in the current prediction cycle period includes:

[0095] Calculate the initial value of the equivalent series resistance of the film capacitor to be tested by using the operating frequency and capacitance value of the film capacitor to be tested;

[0096] The equivalent series resistance of the thin film capacitor to be tested in the current prediction cycle period is determined based on the DC component of the voltage, the initial value of the equivalent series resistance of the thin film capacitor to be tested, the hot spot temperature in the previous prediction cycle period and the aging acceleration factor.

[0097] Specifically, in the embodiment of the present application, the calculation method of the above ESR is improved by introducing an aging acceleration factor. First, the initial value of the equivalent series resistance ESR(0) of the film capacitor to be tested is calculated using the operating frequency and capacitance value of the film capacitor to be tested, that is, ESR(0)=tanδ / 2πfC.

[0098] Further, in the embodiment of the present application, based on the DC component of the voltage, the initial value of the equivalent series resistance ESR(0) of the film capacitor to be tested, the hot spot temperature of the previous prediction cycle period and the aging acceleration factor, the film capacitor to be tested in the current prediction cycle period t is determined. N ESR value ESR(t N ), the process can be specifically expressed according to the following formula:

[0099]

[0100] Where, ESR(0) represents the initial ESR value of the capacitor; U represents the actual operating voltage corresponding to the DC component of the voltage; U r Indicates the rated voltage corresponding to the DC component of the voltage; Ths′ Indicates the hot spot temperature of the film capacitor to be tested during the previous prediction cycle; T r It represents the hot spot temperature of the film capacitor to be tested before the aging test; n represents the voltage coefficient; β represents the ESR temperature coefficient, which can be provided by the manufacturer; a, b and c are all constants.

[0101] It can be understood that, in this embodiment, the aging acceleration factor specifically includes the first aging acceleration factor K p , the second aging acceleration factor K rms and the third aging acceleration factor K f Three items.

[0102] It should be noted that, in other embodiments, the aging acceleration factor may specifically include one or any two of the three types of aging acceleration factors.

[0103] The method of the embodiment of the present application improves the ESR calculation method by introducing an aging acceleration factor, and introduces the aging influencing factors based on the voltage harmonic components into the capacitor ESR calculation, which can further improve the accuracy of calculating the ESR value of the thin film capacitor in different time periods, which is conducive to further improving the accuracy of the life prediction of the thin film capacitor.

[0104] Further, in the embodiment of the present application, the current information of the two ends of the film capacitor to be tested in the current prediction period is obtained in advance, and the current information is processed by FFT transformation, and each current harmonic component is extracted to calculate the effective value of the current component I rms Then, combined with the ESR value of the current prediction period, the heating power P of the film capacitor to be tested is determined. loss , the calculation formula of this process can be expressed as follows:

[0105]

[0106] Furthermore, the temperature rise P of the film capacitor to be tested during the current prediction period is calculated. loss R th , where R th represents the thermal resistance of the film capacitor. Finally, the temperature rise P loss R th and ambient temperature T am The hotspot temperature T of the film capacitor to be tested in the current prediction period is obtained by superposition. hs , the process can be expressed as follows:

[0107] T hs =T am +P loss R th .

[0108] The method of the embodiment of the present application calculates the hotspot temperature of the thin film capacitor in the predicted period by considering the influence of the current harmonic component on the hotspot temperature of the thin film capacitor and combining the quantitative relationship between the equivalent series resistance and the hotspot temperature. This can improve the accuracy of the hotspot temperature calculation of the thin film capacitor in different periods, which is conducive to further improving the accuracy of the life prediction of the thin film capacitor.

[0109] Based on the content of the above embodiment, as an optional embodiment, based on the DC component of the voltage, the hot spot temperature of the current prediction cycle period and the aging acceleration factor, the aging rate of the film capacitor to be tested in the current prediction cycle period is determined, including:

[0110] Determine the change in the hot spot temperature of the film capacitor to be tested during the current prediction cycle period based on the hot spot temperature during the current prediction cycle period and the hot spot temperature of the film capacitor to be tested before the aging test;

[0111] The rated aging rate of the film capacitor to be tested is obtained, and based on the rated aging rate, the hot spot temperature change, the voltage DC component and the aging acceleration factor, the aging rate of the film capacitor to be tested in the current prediction cycle period is determined.

[0112] Specifically, in the embodiment of the present application, based on the DC component of the voltage, the hot spot temperature of the current prediction cycle period and the aging acceleration factor, the specific implementation method of determining the aging rate of the film capacitor to be tested in the current prediction cycle period is as follows:

[0113] First, in the embodiment of the present application, the hot spot temperature T of the film capacitor to be tested before the aging test is performed is obtained. r , and then, using the hot spot temperature T of the current prediction period hs Subtract the hot spot temperature T before the aging test r , the hot spot temperature change of the film capacitor to be tested in the current prediction cycle period can be obtained, which can be expressed as T hs -T r .

[0114] Further, in an embodiment of the present application, the rated aging rate V of the film capacitor to be tested is obtained. r ,in, L r Indicates the rated life of the film capacitor to be tested. And based on the rated aging rate V r , hot spot temperature change (T hs -T r ), voltage DC component and aging acceleration factor, determine the aging rate V of the film capacitor to be tested in the current prediction cycle period t , the process can be expressed as follows:

[0115]

[0116] Where α is the life temperature coefficient of the film capacitor to be tested, which is provided by the manufacturer.

[0117] It can be understood that, in this embodiment, the aging acceleration factor specifically includes the first aging acceleration factor K p , the second aging acceleration factor K rms and the third aging acceleration factor K f Three items.

[0118] It should be noted that, in other embodiments, the aging acceleration factor may specifically include one or any two of the three types of aging acceleration factors.

[0119] The method of the embodiment of the present application can improve the accuracy of calculating the aging rate of the thin film capacitor in different time periods by considering the influence of the voltage DC component and the voltage harmonic component on the aging rate of the thin film capacitor, and combining the quantitative relationship between the hot spot temperature and the aging rate to calculate the aging rate of the predicted cycle period, which is conducive to further improving the accuracy of subsequent thin film capacitor life prediction.

[0120] Based on the content of the above embodiment, as an optional embodiment, after determining the aging rate of the film capacitor to be tested in the current prediction cycle period based on the voltage DC component, the hot spot temperature in the current prediction cycle period and the aging acceleration factor, the method further includes:

[0121] When it is determined that the aging rate does not meet the preset life end threshold condition, obtaining voltage information of both ends of the film capacitor to be tested in the next prediction cycle period;

[0122] Calculating the aging rate of the film capacitor to be tested in the next prediction cycle period by using the voltage information in the next prediction cycle period;

[0123] When it is determined that the aging rate of the next prediction cycle period meets the preset life end threshold condition, the total duration corresponding to the next prediction cycle period is used as the life of the film capacitor to be tested.

[0124] Specifically, in the embodiment of the present application, after determining the aging rate of the film capacitor to be tested in the current prediction cycle period, if it is determined that the aging rate does not meet the preset life end threshold condition, the aging rate V of the current prediction cycle period is described. t Does not satisfy the inequality This means that the accumulated aging degree of the film capacitor has not exceeded its own life span at this time, and further iterative calculation and determination of the aging rate in the next prediction cycle period are required.

[0125] Specifically, when it is determined that the aging rate does not meet the aforementioned preset end-of-life threshold condition, the voltage information of the two ends of the film capacitor to be tested in the next prediction cycle period is first obtained. Similarly, the voltage information of the next prediction cycle period is processed using FFT transformation, and the voltage DC component and voltage harmonic component in the voltage information are extracted, and combined with the aforementioned calculation formula of the aging acceleration factor, the corresponding aging acceleration factor is further re-determined according to the information of the voltage harmonic component.

[0126] Furthermore, in an embodiment of the present application, referring to the aforementioned calculation method, the aging rate of the next predicted cycle period of the thin film capacitor to be tested is calculated using the extracted voltage DC component, the hot spot temperature of the next predicted cycle period and the corresponding aging acceleration factor.

[0127] Furthermore, in an embodiment of the present application, it is determined again whether the currently calculated aging rate meets the preset life end threshold condition. If it is determined that the aging rate meets the preset life end threshold condition, the total duration corresponding to the next prediction cycle period is calculated and used as the life of the film capacitor to be tested.

[0128] It can be understood that if it is determined that the aging rate still does not meet the preset life termination threshold condition, the aging rate of the next predicted cycle period of the film capacitor to be tested will continue to be iteratively calculated until it is determined that the calculated aging rate meets the preset life termination threshold condition, and the life of the film capacitor to be tested is predicted.

[0129] The method of the embodiment of the present application, by exploring the multi-dimensional influencing factors that affect the aging of thin film capacitors, adopts a periodic prediction method for the life of thin film capacitors, and iteratively predicts the life of the thin film capacitors to be tested. While realizing automatic prediction of the life of thin film capacitors, it can also further improve the accuracy of the prediction of the life of thin film capacitors.

[0130] Figure 2 FIG. 2 is a flow chart of the method for predicting the life of a film capacitor provided in an embodiment of the present application. Figure 2 As shown, in the embodiment of the present application, the voltage information and current information of the two ends of the film capacitor to be tested in the current prediction cycle period are first obtained under the aging test condition, and then the voltage information and the current information are respectively subjected to FFT transformation to extract the voltage DC component and the voltage harmonic component in the voltage information in the current prediction cycle period, and the current harmonic component in the current information. According to the expression of the aging acceleration factor mentioned above, the first aging acceleration factor K is calculated based on the voltage harmonic component. p , the second aging acceleration factor L rms and the third aging acceleration factor K f .

[0131] Furthermore, in this embodiment, the operating frequency and capacitance of the film capacitor to be tested are used to calculate the initial value of the equivalent series resistance of the film capacitor to be tested, and then the aging curve of the film capacitor to be tested in the current prediction cycle period is calculated using the above-obtained DC component of the voltage, the initial value of the equivalent series resistance of the film capacitor to be tested, the hot spot temperature in the previous prediction cycle period and the above-obtained aging acceleration factor, that is, the ESR (t N ).

[0132] Furthermore, in this embodiment, the current harmonic component in the above-calculated current information is obtained, and the effective value of the current component is calculated. Using the heating power formula, based on the effective value of the current component and the above-obtained ESR (t N ) Calculate the heating power P of the film capacitor loss Then, based on the current ambient temperature, the hot spot temperature T of the film capacitor to be tested in the current prediction cycle period is calculated. hs .

[0133] Next, according to the aging rate calculation formula, the hot spot temperature T in the current prediction period is used. hs The aging acceleration factor calculated above is used to determine the aging rate of the film capacitor to be tested during the current prediction cycle period.

[0134] Furthermore, when it is determined that the aging rate meets the preset life termination threshold condition described above, it means that the current aging degree of the film capacitor to be tested has exceeded its own life. At this time, the life of the film capacitor to be tested can be determined according to the total duration corresponding to the current prediction cycle period, thereby realizing automatic prediction of the life of the film capacitor to be tested.

[0135] Furthermore, when it is determined that the aging rate does not meet the preset life end threshold condition described above, the iterative calculation is returned, and the N value is increased by 1, that is, entering the next prediction cycle period, and then obtaining the voltage information across the two ends of the film capacitor to be tested in the next prediction cycle period.

[0136] Similarly, the aforementioned method of calculating the aging rate of the film capacitor to be tested in the current prediction cycle period can be referred to, and the calculation can be repeated to calculate the aging rate of the film capacitor to be tested in the next prediction cycle period using the voltage information of the next prediction cycle period, and then the aging rate of the next prediction cycle period can be further determined. In this way, an iterative calculation is formed until it is determined that the currently calculated aging rate meets the preset life end threshold condition, and the life L of the film capacitor to be tested is obtained according to the total duration corresponding to the current prediction cycle period.

[0137] For example, in a specific embodiment of the present application, the film capacitor is a capacitor of a modular multilevel converter submodule, and its rated capacitance is 1100 μF, ESR(0)=1.8 mΩ, R th =2.3K / W, rated DC voltage is 1000V, T r =60℃,L r =3.5×10 5 h. The actual working voltage U can be measured rms =1000V, I rms =90A, ambient temperature T am =25℃.

[0138] In addition, the model parameters are set to a = -0.5, b = -6.1, c = -2.6, n = 4.4, α = 10, β = 6.34, Δt = 1h. By using the above prediction method of the present application, the initial hot spot temperature is calculated to be 58°C, and the life of the film capacitor can be predicted to be 127224h, which is less than 10% of the actual life of its engineering application, achieving a good prediction effect.

[0139] The following is a description of the life prediction device for a thin film capacitor provided by the present invention. The life prediction device for a thin film capacitor described below and the life prediction method for a thin film capacitor described above can be referred to each other.

[0140] Figure 3 is a schematic diagram of the structure of the device for predicting the life of a thin film capacitor provided in an embodiment of the present application, such as Figure 3 As shown, including:

[0141] An acquisition module 10 is used to obtain voltage information of both ends of the film capacitor to be tested in the current prediction cycle period under the aging test condition;

[0142] A first processing module 20 is used to extract a voltage DC component and a voltage harmonic component from the voltage information, and determine an aging acceleration factor based on the voltage harmonic component;

[0143] The second processing module 30 is used to determine the aging rate of the film capacitor to be tested in the current prediction cycle period based on the DC component of the voltage, the hot spot temperature in the current prediction cycle period and the aging acceleration factor; the hot spot temperature in the current prediction cycle period is determined based on the equivalent series resistance and the ambient temperature in the current prediction cycle period;

[0144] The prediction module 40 is used to predict the life of the film capacitor to be tested based on the total duration corresponding to the current prediction cycle period when it is determined that the aging rate meets the preset life end threshold condition.

[0145] It can be understood that the detailed functional implementation of each of the above-mentioned units / modules can be found in the introduction of the aforementioned method embodiment, and will not be repeated here.

[0146] It should be understood that the above-mentioned device is used to execute the method in the above-mentioned embodiment. The implementation principle and technical effect of the corresponding program module in the device are similar to those described in the above-mentioned method. The working process of the device can refer to the corresponding process in the above-mentioned method, which will not be repeated here.

[0147] The thin film capacitor life prediction device of the embodiment of the present application adopts a periodic prediction method for the life of the thin film capacitor by combining the influence of the aging process of the thin film capacitor on its life, and uses the voltage information at both ends of the thin film capacitor to be tested in the current prediction period under the aging test condition to extract the voltage DC component and voltage harmonic component therein, and by exploring the multi-dimensional influencing factors affecting the aging of the thin film capacitor, the influence of the voltage harmonic component on the aging of the thin film capacitor is considered, and the aging acceleration factor is constructed using the extracted voltage harmonic component, and then the aging rate of the thin film capacitor to be tested in the current prediction period is determined using the aforementioned voltage DC component, the hot spot temperature in the current prediction period and the aging acceleration factor, so as to judge the current aging degree of the thin film capacitor, thereby realizing automatic prediction of the life of the thin film capacitor without human intervention, which can greatly improve the accuracy and efficiency of the prediction of the life of the thin film capacitor.

[0148] Based on the method in the above embodiment, the embodiment of the present application provides an electronic device, such as Figure 4 As shown, the electronic device may include: a processor (Processor) 410, a communication interface (CommunicationsInterface) 420, a memory (Memory) 430 and a communication bus 440, wherein the processor 410, the communication interface 420, and the memory 430 communicate with each other through the communication bus 440. The processor 410 may call the logic instructions in the memory 430 to execute the method in the above embodiment.

[0149] In addition, the logic instructions in the above-mentioned memory 430 can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application.

[0150] Based on the method in the above embodiment, an embodiment of the present application provides a computer-readable storage medium, which stores a computer program. When the computer program runs on a processor, the processor executes the method in the above embodiment.

[0151] Based on the method in the above embodiment, an embodiment of the present application provides a computer program product. When the computer program product runs on a processor, the processor executes the method in the above embodiment.

[0152] It is understandable that the processor in the embodiment of the present application may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0153] The method steps in the embodiments of the present application can be implemented by hardware or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, mobile hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can be located in an ASIC.

[0154] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer instructions may be transmitted from a website site, a computer, a server or a data center to another website site, a computer, a server or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or a data center that includes one or more available media integrated. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)), etc.

[0155] It should be understood that the various numerical numbers involved in the embodiments of the present application are only used for the convenience of description and are not used to limit the scope of the embodiments of the present application.

[0156] It should be understood that expressions such as "including" and "may include" that may be used in the present application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In the present application, terms such as "including" and / or "having" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components, or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0157] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A method for predicting the life of a film capacitor, characterized in that: include: Obtaining voltage information at both ends of the film capacitor to be tested during the current prediction cycle period under aging test conditions; extracting a voltage DC component and a voltage harmonic component from the voltage information, and determining an aging acceleration factor based on the voltage harmonic component; Determine the aging rate of the film capacitor to be tested in the current prediction cycle period based on the voltage DC component, the hot spot temperature in the current prediction cycle period and the aging acceleration factor; the hot spot temperature in the current prediction cycle period is determined based on the equivalent series resistance and the ambient temperature in the current prediction cycle period; When it is determined that the aging rate meets a preset life end threshold condition, the life of the thin film capacitor to be tested is determined according to the total duration corresponding to the current prediction cycle period.

2. The method for predicting the life of a film capacitor according to claim 1, characterized in that: The step of determining the aging rate of the thin film capacitor to be tested in the current prediction cycle period based on the voltage DC component, the hot spot temperature in the current prediction cycle period, and the aging acceleration factor comprises: Determine the change in the hot spot temperature of the thin film capacitor to be tested during the current prediction cycle period based on the hot spot temperature during the current prediction cycle period and the hot spot temperature of the thin film capacitor to be tested before the aging test; The rated aging rate of the film capacitor to be tested is obtained, and based on the rated aging rate, the hot spot temperature change, the voltage DC component and the aging acceleration factor, the aging rate of the film capacitor to be tested in the current prediction cycle period is determined.

3. The method for predicting the life of a film capacitor according to claim 1, characterized in that: Before determining the aging rate of the film capacitor to be tested in the current prediction cycle period based on the voltage DC component, the hot spot temperature in the current prediction cycle period and the aging acceleration factor, the method further includes: Determine the equivalent series resistance of the thin film capacitor to be tested during the current prediction cycle period; Based on the equivalent series resistance of the current prediction cycle period and the current information of both ends of the thin film capacitor to be tested in the current prediction cycle period, the heating power of the thin film capacitor to be tested is determined to calculate the temperature rise of the thin film capacitor to be tested in the current prediction cycle period; The hot spot temperature of the thin film capacitor to be tested in the current prediction cycle period is determined according to the temperature rise and the ambient temperature.

4. The method for predicting the life of a film capacitor according to claim 3, characterized in that: The determining the equivalent series resistance of the thin film capacitor to be tested in the current prediction cycle period includes: Calculating an initial value of an equivalent series resistance of the thin film capacitor to be tested by using an operating frequency and a capacitance value of the thin film capacitor to be tested; The equivalent series resistance of the thin film capacitor to be tested in the current prediction cycle period is determined based on the voltage DC component, the initial value of the equivalent series resistance of the thin film capacitor to be tested, the hot spot temperature in the previous prediction cycle period and the aging acceleration factor.

5. The method for predicting the life of a film capacitor according to any one of claims 1 to 4, characterized in that: After determining the aging rate of the film capacitor to be tested in the current prediction cycle period based on the voltage DC component, the hot spot temperature in the current prediction cycle period and the aging acceleration factor, the method further includes: When it is determined that the aging rate does not meet the preset life end threshold condition, obtaining voltage information of both ends of the thin film capacitor to be tested in the next prediction cycle period; Calculating the aging rate of the film capacitor to be tested in the next prediction cycle period by using the voltage information in the next prediction cycle period; When it is determined that the aging rate of the next prediction cycle period meets the preset life end threshold condition, the life of the thin film capacitor to be tested is determined according to the total time length corresponding to the next prediction cycle period.

6. The method for predicting the life of a film capacitor according to any one of claims 1 to 4, characterized in that: The determining of the aging acceleration factor based on the voltage harmonic component comprises: Based on the voltage harmonic components, determining a first amplitude, a first effective value, and a first peak value of the fundamental voltage component, and a second amplitude, a second effective value, and a second peak value of each voltage harmonic component; Obtaining a first aging acceleration factor according to a ratio of the second peak value to the first peak value; Obtaining a second aging acceleration factor according to a ratio of the second effective value to the first effective value; determining a third aging acceleration factor based on a ratio of the second amplitude to the first amplitude; The aging acceleration factor includes at least one of the first aging acceleration factor, the second aging acceleration factor, and the third aging acceleration factor.

7. A device for predicting the life of a film capacitor, characterized in that: include: An acquisition module is used to obtain voltage information of both ends of the film capacitor to be tested in the current prediction cycle period under the aging test condition; A first processing module, configured to extract a voltage DC component and a voltage harmonic component from the voltage information, and determine an aging acceleration factor based on the voltage harmonic component; A second processing module is used to determine the aging rate of the film capacitor to be tested in the current prediction cycle period based on the voltage DC component, the hot spot temperature in the current prediction cycle period and the aging acceleration factor; the hot spot temperature in the current prediction cycle period is determined based on the equivalent series resistance and the ambient temperature in the current prediction cycle period; The prediction module is used to predict the life of the thin film capacitor to be tested based on the total duration corresponding to the current prediction cycle period when it is determined that the aging rate meets a preset life end threshold condition.

8. An electronic device, characterized in that: include: at least one memory for storing a computer program; At least one processor is used to execute the program stored in the memory. When the program stored in the memory is executed, the processor is used to execute the method according to any one of claims 1 to 6.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program runs on a processor, the processor is caused to execute the method according to any one of claims 1 to 6.

10. A computer program product, characterized in that When the computer program product runs on a processor, the processor is caused to execute the method according to any one of claims 1 to 6.

Images