Automobile capacitor ground insulation detection method

Abstract

The invention provides an automobile capacitor ground insulation detection method, and relates to the technical field of capacitor detection, and the method comprises the steps: collecting a pulse reflection signal received in a pulse receiving module; comparing the frequency domain characteristics between the high-frequency pulse signal and the pulse reflection signal to obtain the signal loss of the high-frequency pulse signal in the reflection process, and determining the reflection coefficient of the tested automobile capacitor according to the signal loss and the capacity characteristics of the tested automobile capacitor; determining impedance matching deviation between the automobile capacitor and a grounding loop, and determining a dielectric loss factor of the tested automobile capacitor through the impedance matching deviation and waveform distortion characteristics of the pulse reflection signal; determining the ground insulation loss characteristic of the automobile capacitor according to the dielectric loss factor and the reflection coefficient, and determining the ground insulation state of the automobile capacitor based on the loss characteristic, the method can achieve the loss evaluation of the ground insulation state of the automobile capacitor in combination with the high-frequency pulse signal, and can improve the evaluation reliability of the ground insulation state of the automobile capacitor.

Description

Technical Field

[0001] The present application relates to the technical field of capacitance detection, and more specifically, to a method for detecting the insulation of an automotive capacitor to the ground. Background Art

[0002] With the continuous growth of the global automotive industry, especially the rapid development of new energy vehicles, the market demand for automotive capacitors has increased significantly. Automotive capacitors play an important role in improving automotive performance, ensuring safety, and reducing energy consumption. In recent years, the popularization of new energy vehicles has put forward higher requirements for the performance of capacitors, promoting the research and application of high-performance and high-reliability capacitors.

[0003] However, traditional automotive capacitor evaluation methods usually rely on static electrical measurements or simple impedance analysis. Although they can provide basic capacitor characteristic data, it is difficult to comprehensively reflect the dynamic changes of the capacitor under actual working conditions. Static measurements are usually carried out without considering the internal medium of the capacitor and the external working environment, and it is difficult to capture the behavioral changes of the capacitor under the influence of different electric fields and temperatures. Especially under complex working conditions such as high frequency, high temperature, or vibration, the performance of the capacitor will change significantly, and traditional methods cannot adapt to this change. Therefore, how to combine high-frequency pulse signals to achieve loss evaluation of the insulation state of automotive capacitors to the ground, so as to improve the reliability of the evaluation of the insulation state of automotive capacitors to the ground, is a difficult problem faced by the industry. Summary of the Invention

[0004] The present application provides a method for detecting the insulation of an automotive capacitor to the ground, which can combine high-frequency pulse signals to achieve loss evaluation of the insulation state of automotive capacitors to the ground, thereby improving the reliability of the evaluation of the insulation state of automotive capacitors to the ground.

[0005] The present application provides a method for detecting the insulation of an automotive capacitor to the ground, and the insulation detection method includes the following steps:

[0006] Set a pulse emission module and a pulse reception module in the vehicle, use the pulse emission module to emit high-frequency pulse signals to the automotive capacitor to be measured, and collect the pulse reflection signals received in the pulse reception module;

[0007] Compare the frequency domain characteristics between the high-frequency pulse signal and the pulse reflection signal to obtain the signal loss during the reflection of the high-frequency pulse signal, and determine the reflection coefficient of the automotive capacitor to be measured through the signal loss and the capacitance characteristics of the automotive capacitor to be measured;

[0008] Determine the impedance matching deviation between the automotive capacitor and the grounding circuit, and determine the dielectric loss factor of the automotive capacitor to be measured through the impedance matching deviation and the waveform distortion characteristics of the pulse reflection signal;

[0009] Determine the loss characteristics of the vehicle capacitor's insulation to the ground based on the dielectric loss factor and the reflection coefficient, and determine the insulation state of the vehicle capacitor to the ground based on the loss characteristics.

[0010] In this embodiment, comparing the frequency-domain characteristics between the high-frequency pulse signal and the pulse reflection signal to obtain the signal loss of the high-frequency pulse signal during the reflection process specifically includes:

[0011] Perform a frequency-domain transformation on the high-frequency pulse signal to obtain the frequency-domain amplitude spectrum and phase spectrum of the input signal, and then determine the input power spectral density of the frequency-domain characteristics in the input signal through the frequency-domain amplitude spectrum and phase spectrum of the input signal;

[0012] Perform a frequency-domain transformation on the pulse reflection signal to obtain the frequency-domain amplitude spectrum and phase spectrum of the output signal, and then determine the output power spectral density of the frequency-domain characteristics in the output signal through the frequency-domain amplitude spectrum and phase spectrum of the input signal;

[0013] Perform a phase separation comparison between the input power spectral density and the output power spectral density, and then obtain the signal loss of the high-frequency pulse signal during the reflection process.

[0014] In this embodiment, determining the reflection coefficient of the vehicle capacitor under test through the signal loss and the capacitance characteristics of the vehicle capacitor under test specifically includes:

[0015] Obtain the standard impedance value and capacitance characteristics of the vehicle capacitor;

[0016] Determine the characteristic impedance value of the vehicle capacitor through the capacitance characteristics and the signal loss;

[0017] Determine the reflection coefficient of the vehicle capacitor under test according to the characteristic impedance value and the standard impedance value.

[0018] In this embodiment, the high-frequency pulse signal is a high-frequency ultra-wideband pulse signal shaped by Nyquist pulses.

[0019] In this embodiment, determining the impedance matching deviation between the vehicle capacitor and the grounding loop specifically includes:

[0020] Obtain the rated matching impedance value between the vehicle capacitor and the grounding loop;

[0021] Collect the equivalent impedance between the vehicle capacitor and the grounding loop;

[0022] Determine the impedance matching deviation between the vehicle capacitor and the grounding loop through the equivalent impedance and the rated matching impedance value.

[0023] In this embodiment, determining the dielectric loss factor of the vehicle capacitor under test through the impedance matching deviation and the waveform distortion characteristics of the pulse reflection signal specifically includes:

[0024] Determine the dielectric loss angle of the measured automotive capacitor according to the waveform distortion characteristics of the pulse reflection signal;

[0025] Perform loss correlation matching on the node loss angle and the impedance matching deviation to obtain the dielectric loss factor of the measured automotive capacitor.

[0026] In this embodiment, determining the loss characteristics of the automotive capacitor's insulation to the ground according to the dielectric loss factor and the reflection coefficient specifically includes:

[0027] Construct a loss evaluation algorithm based on the equivalent circuit model of the automotive capacitor;

[0028] Use the dielectric loss factor as the loss parameter in this loss evaluation algorithm;

[0029] Use the reflection coefficient as the impedance matching parameter in this loss evaluation algorithm;

[0030] Use this loss evaluation algorithm to evaluate the loss characteristics of the automotive capacitor's insulation to the ground, and obtain the loss characteristics of the automotive capacitor's insulation to the ground.

[0031] In this embodiment, determining the insulation state of the automotive capacitor to the ground based on the loss characteristics specifically includes:

[0032] Obtain the loss mapping table of the automotive capacitor's insulation to the ground;

[0033] Select the insulation state corresponding to the loss characteristics from the loss mapping table as the insulation state of the automotive capacitor to the ground.

[0034] In this embodiment, the pulse emission module is an ultra-wideband pulse generator.

[0035] In this embodiment, the pulse receiving module is a high-sensitivity radio frequency sampling receiver.

[0036] The technical solutions provided by the disclosed embodiments of the present application have the following beneficial effects:

[0037] A pulse transmitting module and a pulse receiving module are arranged in a vehicle. The pulse transmitting module is used to transmit a high-frequency pulse signal to the capacitance of the vehicle to be measured, and the pulse reflection signal received in the pulse receiving module is collected. The frequency domain characteristics between the high-frequency pulse signal and the pulse reflection signal are compared to obtain the signal loss during the reflection of the high-frequency pulse signal. The reflection coefficient of the capacitance of the vehicle to be measured is determined based on the signal loss and the capacitance characteristic of the capacitance of the vehicle to be measured. The impedance matching deviation between the vehicle capacitance and the grounding loop is determined, and the dielectric loss factor of the capacitance of the vehicle to be measured is determined based on the impedance matching deviation and the waveform distortion characteristic of the pulse reflection signal. The loss characteristic of the vehicle capacitance with respect to ground insulation is determined based on the dielectric loss factor and the reflection coefficient, and the ground insulation state of the vehicle capacitance is determined based on the loss characteristic.

[0038] It can be seen that in this application, first of all, the reflection coefficient reflects the proportion of the electrical signal reflected from the surface of the capacitor. The reflection coefficient is directly related to the voltage distribution and energy transmission between the capacitor and the ground. If the reflection coefficient is too high, it indicates that the insulation performance of the capacitor is poor, there is a large amount of energy reflection, which may lead to overheating or failure. The signal loss can accurately reflect the impedance matching between the capacitor and the grounding loop. Further deriving the reflection coefficient of the capacitor based on this signal loss and the capacitance characteristic of the capacitance of the vehicle to be measured can provide a reliable basis for evaluating the insulation performance of the capacitor under dynamic working conditions, thereby improving the reliability of the evaluation results. Furthermore, the dielectric loss factor is a parameter that describes the energy loss of the capacitor dielectric during operation, and is usually closely related to the dielectric material characteristics and electric field strength of the capacitor. An excessive loss factor will lead to low capacitor efficiency and even affect the overall performance and life of the vehicle capacitor. By combining the dielectric loss factor with the reflection coefficient, the loss characteristic of the vehicle capacitance with respect to ground insulation can be comprehensively evaluated. The accurate determination of the dielectric loss factor helps to evaluate the heat loss and power consumption of the capacitor in actual use, thereby improving the accurate judgment of the ground insulation state and avoiding the accident risk caused by capacitor aging or damage.

[0039] In summary, the technical solution adopted in this application can combine high-frequency pulse signals to realize the loss evaluation of the ground insulation state of vehicle capacitors, thereby improving the evaluation reliability of the ground insulation state of vehicle capacitors. Description of the Drawings

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0041] Figure 1It is an exemplary flowchart of the method for detecting the ground insulation of automotive capacitors provided by the present application;

[0042] Figure 2 It is an exemplary flowchart of determining the reflection coefficient of the measured automotive capacitor provided by the present application;

[0043] Figure 3 It is an exemplary flowchart of determining the impedance matching deviation between the automotive capacitor and the grounding loop provided by the present application. Detailed implementation manners

[0044] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0045] The embodiment of the present application provides a method for detecting the ground insulation of automotive capacitors. The core is to set a pulse emission module and a pulse reception module in the vehicle, use the pulse emission module to emit a high-frequency pulse signal to the measured automotive capacitor, and collect the pulse reflection signal received in the pulse reception module; compare the frequency domain characteristics between the high-frequency pulse signal and the pulse reflection signal to obtain the signal loss during the reflection process of the high-frequency pulse signal, and determine the reflection coefficient of the measured automotive capacitor through the signal loss and the capacitance characteristics of the measured automotive capacitor; determine the impedance matching deviation between the automotive capacitor and the grounding loop, and determine the dielectric loss factor of the measured automotive capacitor through the impedance matching deviation and the waveform distortion characteristics of the pulse reflection signal; determine the loss characteristics of the ground insulation of the automotive capacitor according to the dielectric loss factor and the reflection coefficient, and determine the ground insulation state of the automotive capacitor based on the loss characteristics. By adopting the above solution, the loss evaluation of the ground insulation state of the automotive capacitor can be realized in combination with the high-frequency pulse signal, thereby improving the evaluation reliability of the ground insulation state of the automotive capacitor.

[0046] To better understand the above technical solutions, the above technical solutions will be described in detail below in conjunction with the accompanying drawings of the specification and specific implementation manners. Refer to Figure 1 As shown, this figure is an exemplary flowchart of a method for detecting the ground insulation of automotive capacitors according to this embodiment of the present application. The insulation detection method includes the following steps:

[0047] In step S1, a pulse emission module and a pulse reception module are set in the vehicle, the pulse emission module is used to emit a high-frequency pulse signal to the measured automotive capacitor, and the pulse reflection signal received in the pulse reception module is collected.

[0048] It should be noted that in this application, the high-frequency pulse signal is a high-frequency ultra-wideband pulse signal shaped by Nyquist pulses; the pulse transmitting module is an ultra-wideband pulse generator; the pulse receiving module is a high-sensitivity radio frequency sampling receiver. Specifically, when implemented, a pulse transmitting module and a pulse receiving module are set in the vehicle, and the pulse transmitting module is used to transmit a high-frequency pulse signal to the capacitance of the vehicle to be measured, so that the pulse sensor in the pulse receiving module is used to collect the received pulse reflection signal.

[0049] In step S2, the frequency-domain characteristics between the high-frequency pulse signal and the pulse reflection signal are compared to obtain the signal loss of the high-frequency pulse signal during the reflection process, and the reflection coefficient of the capacitance of the vehicle to be measured is determined through the signal loss and the capacitance characteristics of the capacitance of the vehicle to be measured.

[0050] A pulse transmitting module and a pulse receiving module are set in the vehicle, and the pulse transmitting module is used to transmit a high-frequency pulse signal to the capacitance of the vehicle to be measured. The following method can be specifically adopted to collect the pulse reflection signal received in the pulse receiving module, that is:

[0051] Perform a frequency-domain transformation on the high-frequency pulse signal to obtain the frequency-domain amplitude spectrum and phase spectrum of the input signal, and then determine the input power spectral density of the frequency-domain characteristics in the input signal through the frequency-domain amplitude spectrum and phase spectrum of the input signal;

[0052] Perform a frequency-domain transformation on the pulse reflection signal to obtain the frequency-domain amplitude spectrum and phase spectrum of the output signal, and then determine the output power spectral density of the frequency-domain characteristics in the output signal through the frequency-domain amplitude spectrum and phase spectrum of the input signal;

[0053] Perform a phase separation comparison between the input power spectral density and the output power spectral density, and then obtain the signal loss of the high-frequency pulse signal during the reflection process.

[0054] It should be noted that in this application, the signal loss represents the attenuation degree of the energy of the high-frequency pulse signal during the propagation and reflection processes; the frequency-domain amplitude spectrum represents the amplitude distribution characteristics of the signal in the frequency domain, and the phase spectrum represents the phase change characteristics of the signal in the frequency domain; the input power spectral density represents the power distribution of each frequency component of the high-frequency pulse signal at the input end; the output power spectral density represents the power distribution of each frequency component of the pulse reflection signal at the receiving end.

[0055] In specific implementation, first, perform Fourier transform on the high-frequency pulse signal to obtain the signal frequency-domain spectrum map. Obtain the frequency-domain amplitude spectrum and phase spectrum from this signal frequency-domain spectrum map as the frequency-domain amplitude spectrum and phase spectrum of the input signal. Select a power spectral density formula, use the frequency-domain amplitude spectrum as the amplitude parameter in the power spectral density formula, and use the phase spectrum as the phase parameter in the power spectral density formula. Thus, calculate the power spectral density using this power spectral density formula as the input power spectral density of the frequency-domain characteristics in the input signal. Then, perform Fourier transform on the pulse reflection signal to obtain the signal frequency-domain spectrum map. Obtain the frequency-domain amplitude spectrum and phase spectrum from this signal frequency-domain spectrum map as the frequency-domain amplitude spectrum and phase spectrum of the output signal. Select a power spectral density formula, use the frequency-domain amplitude spectrum as the amplitude parameter in the power spectral density formula, and use the phase spectrum as the phase parameter in the power spectral density formula. Thus, calculate the power spectral density using this power spectral density formula as the output power spectral density of the frequency-domain characteristics in the output signal. Finally, the phase separation technique can be used to separately separate the phase values of the input power spectral density and the output power spectral density at each phase point. For each phase point, take the natural logarithm of the ratio of the phase value of the input power spectral density at the phase point to the phase value of the output power spectral density at the phase point as the phase loss value at the phase point. In this way, the phase loss values at each phase point can be obtained, and the sum of all loss values is used as the signal loss during the reflection of the high-frequency pulse signal.

[0056] Preferably, in this embodiment, refer to Figure 2 As shown, this figure is an exemplary flowchart for determining the reflection coefficient of the measured automotive capacitor in the embodiment of the present application. In this embodiment, the following steps can be specifically adopted to determine the reflection coefficient of the measured automotive capacitor based on the signal loss and the capacitance characteristics of the measured automotive capacitor:

[0057] First, in step S21, obtain the standard impedance value and capacitance characteristics of the automotive capacitor;

[0058] Then, in step S22, determine the characteristic impedance value of the automotive capacitor based on the capacitance characteristics and the signal loss;

[0059] Finally, in step S23, determine the reflection coefficient of the measured automotive capacitor based on the characteristic impedance value and the standard impedance value.

[0060] It should be noted that in this application, the reflection coefficient represents the reflection ratio of the high-frequency pulse signal at the interface between the automotive capacitor and the grounding loop. Specifically, in implementation, first, the standard impedance value and capacitance characteristics of the automotive capacitor can be obtained from the vehicle's user manual. The standard impedance value represents the reference impedance of the automotive capacitor under design and test conditions, and the capacitance characteristics represent the capacitance of the automotive capacitor. Then, the natural logarithm of the ratio of the signal loss to the capacitance characteristics can be used as the characteristic impedance value of the automotive capacitor, which represents the inherent impedance of the automotive capacitor and its connecting wires under high-frequency conditions. Finally, the calculation result of (characteristic impedance value - standard impedance value) / (characteristic impedance value + standard impedance value) can be used as the reflection coefficient of the measured automotive capacitor.

[0061] In step S3, determine the impedance matching deviation between the automotive capacitor and the grounding loop, and determine the dielectric loss factor of the measured automotive capacitor based on the impedance matching deviation and the waveform distortion characteristics of the pulse reflection signal.

[0062] Preferably, in this embodiment, refer to Figure 3 As shown, this figure is an exemplary flowchart for determining the impedance matching deviation between the automotive capacitor and the grounding loop in an embodiment of this application. In this embodiment, the impedance matching deviation between the automotive capacitor and the grounding loop can be specifically implemented by the following steps:

[0063] First, in step S31, obtain the rated matching impedance value between the automotive capacitor and the grounding loop.

[0064] Then, in step S32, collect the equivalent impedance between the automotive capacitor and the grounding loop.

[0065] Finally, in step S33, determine the impedance matching deviation between the automotive capacitor and the grounding loop based on the equivalent impedance and the rated matching impedance value.

[0066] It should be noted that in this application, the impedance matching deviation represents the degree of deviation between the actual impedance and the rated matching impedance between the automotive capacitor and the grounding loop. Specifically, in implementation, first, the rated matching impedance value between the automotive capacitor and the grounding loop can be obtained from the vehicle's user manual, which represents the theoretical impedance value of the automotive capacitor and the grounding loop under the best energy transfer conditions. Then, an impedance analyzer can be used to collect the equivalent impedance between the automotive capacitor and the grounding loop, which represents the comprehensive impedance characteristics of the automotive capacitor and its grounding loop at a specific frequency. Finally, the absolute value of the difference between the rated matching impedance value and the equivalent impedance can be used as the impedance matching deviation between the automotive capacitor and the grounding loop.

[0067] In this embodiment, the dielectric loss factor of the measured automotive capacitor can be specifically determined based on the impedance matching deviation and the waveform distortion characteristics of the pulse reflection signal by the following steps:

[0068] Determine the dielectric loss angle of the measured automotive capacitor according to the waveform distortion characteristics of the pulse reflection signal;

[0069] Perform loss correlation matching on the node loss angle and the impedance matching deviation to obtain the dielectric loss factor of the measured automotive capacitor.

[0070] In specific implementation, first, a time-domain analysis algorithm can be used to perform time-domain analysis on the pulse reflection signal, so as to calculate the amplitude distortion degree and phase offset of the pulse reflection signal as the waveform distortion characteristics of the pulse reflection signal, and then use the ratio of the amplitude distortion degree to the phase offset as the tangent value of the dielectric loss angle, so as to obtain the dielectric loss angle of the measured automotive capacitor; then, the greater the impedance matching deviation, usually means the greater the loss of the dielectric material inside the capacitor, which will cause more obvious distortion to the waveform. Use the relationship between the above waveform distortion and impedance deviation to initialize a correlation matching model based on regression analysis. Take the node loss angle as the independent variable in this correlation matching model, take the impedance matching deviation as the covariate in this correlation matching model, and use this correlation matching model for correlation matching, so as to use the matching quantization value of this correlation matching model as the dielectric loss factor of the measured automotive capacitor.

[0071] It should be noted that in this application, the dielectric loss factor represents the energy loss ratio of the automotive capacitor under the action of an alternating current electric field; the dielectric loss angle represents the phase deviation between the active loss component and the reactive component in the equivalent circuit of the capacitor; the correlation matching model is a method based on regression analysis, which is used to establish a quantitative relationship between the node loss angle and the impedance matching deviation, and evaluate the dielectric loss factor of the automotive capacitor through the matching quantization value. In this correlation matching model, the node loss angle is used as the independent variable, representing the loss angle of the capacitor dielectric under the action of an alternating current electric field; the impedance matching deviation is used as the covariate, reflecting the impedance deviation degree between the automotive capacitor and the grounding loop. Through regression analysis, the correlation matching model fits the correlation characteristics of the two to determine the functional relationship between the two. Thus, when new loss angle and impedance deviation data are input, the matching quantization value can be calculated, and this value is the dielectric loss factor of the measured automotive capacitor. This method can optimize the matching strategy using historical data, improve the accuracy of dielectric loss evaluation, and adapt to different capacitor structures and working environments by adjusting the correlation matching model parameters.

[0072] In step S4, determine the loss characteristics of the automotive capacitor's insulation to the ground according to the dielectric loss factor and the reflection coefficient, and determine the insulation state of the automotive capacitor to the ground based on the loss characteristics.

[0073] In this embodiment, the method for determining the loss characteristics of the automotive capacitor's insulation to the ground according to the dielectric loss factor and the reflection coefficient can be specifically as follows:

[0074] Construct a loss evaluation algorithm based on the equivalent circuit model of automotive capacitors;

[0075] Use the dielectric loss factor as the loss parameter in the loss evaluation algorithm;

[0076] Use the reflection coefficient as the impedance matching parameter in the loss evaluation algorithm;

[0077] Use the loss evaluation algorithm to evaluate the loss characteristics of the automotive capacitor's insulation to the ground, and obtain the loss characteristics of the automotive capacitor's insulation to the ground.

[0078] It should be noted that in this application, the loss evaluation algorithm is a method based on equivalent circuit modeling, which is used to quantitatively analyze the energy loss characteristics of automotive capacitors under the condition of insulation to the ground. This loss evaluation algorithm relies on the equivalent circuit model and represents the automotive capacitor as a composite circuit structure including a series resistor (characterizing dielectric loss), a series inductor (reflecting parasitic effects), and a parallel capacitor (describing capacitor characteristics). During the loss evaluation process, first, use the dielectric loss factor as the loss parameter to evaluate the active power loss of the capacitor dielectric under the action of an alternating electric field; second, use the reflection coefficient as the impedance matching parameter to analyze the energy reflection and loss of high-frequency signals in the case of impedance mismatch. Through the loss evaluation algorithm, combine the frequency-domain and time-domain characteristics to calculate the loss characteristics of the automotive capacitor, and realize the quantitative evaluation of the capacitor insulation state. This method can accurately identify the loss sources of the capacitor, improve the accuracy of the evaluation of the insulation performance to the ground, and provide theoretical support for the safety monitoring and optimal design of automotive capacitors.

[0079] In this embodiment, to determine the insulation state of the automotive capacitor to the ground based on the loss characteristics, the following method can be specifically adopted, that is:

[0080] Obtain the loss mapping table of the automotive capacitor's insulation to the ground;

[0081] Select the insulation state corresponding to the loss characteristics from the loss mapping table as the insulation state of the automotive capacitor to the ground.

[0082] It should be noted that in this application, the ground insulation state represents the insulation performance level of the automotive capacitor relative to the ground; the loss mapping table represents the correspondence between the insulation state and the loss characteristics. The loss mapping table is a multi-dimensional loss parameter-insulation state correspondence matrix constructed based on experimental data and theoretical analysis, and is used to quickly evaluate the ground insulation state of the automotive capacitor. During the evaluation process, first, obtain the ground insulation loss mapping table of the automotive capacitor, which contains the standard insulation states corresponding to different dielectric loss factors, reflection coefficients, and other loss characteristics; then, through the calculated loss characteristics, perform matching and screening in the loss mapping table, and extract the insulation state closest to it as the final ground insulation state of the automotive capacitor. This loss mapping process can improve the accuracy of insulation evaluation in a data-driven manner, reduce the computational complexity, and provide a reliable basis for the health monitoring and fault warning of automotive capacitors.

[0083] It can be seen that in this application, first, the reflection coefficient reflects the proportion of the electrical signal reflected back from the capacitor surface. The reflection coefficient is directly related to the voltage distribution and energy transmission between the capacitor and the ground. If the reflection coefficient is too high, it indicates that the insulation performance of the capacitor is poor, there is a large amount of energy reflection, which may lead to overheating or failure. The signal loss can accurately reflect the impedance matching situation between the capacitor and the grounding circuit. Further deriving the reflection coefficient of the capacitor based on this signal loss and the capacitance characteristics of the measured automotive capacitor can provide a reliable basis for evaluating the insulation performance of the capacitor under dynamic working conditions, thereby improving the reliability of the evaluation results; furthermore, the dielectric loss factor is a parameter that describes the energy loss of the capacitor dielectric during operation, and is usually closely related to the dielectric material characteristics and electric field strength of the capacitor. An excessive loss factor will lead to low capacitor efficiency and even affect the overall performance and lifespan of the automotive capacitor. By combining the dielectric loss factor with the reflection coefficient, the loss characteristics of the capacitor's ground insulation can be comprehensively evaluated. The accurate determination of the dielectric loss factor helps to evaluate the heat loss and power consumption of the capacitor during actual use, thereby improving the accurate judgment of the ground insulation state and avoiding the accident risk caused by capacitor aging or damage.

[0084] In summary, the technical solution adopted in this application can combine high-frequency pulse signals to achieve the loss evaluation of the ground insulation state of automotive capacitors, thereby improving the evaluation reliability of the ground insulation state of automotive capacitors.

[0085] This application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams can be implemented by computer program instructions, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can also be implemented. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a means for implementing the functions specified in one Figure 1 flow or multiple flows and / or blocks Figure 1 or a means for implementing the functions specified in multiple blocks.

[0086] Those of ordinary skill in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing relevant hardware through a program. This program can be stored in a computer-readable storage medium, which includes read-only memory (ROM), random access memory (RAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), one-time programmable read-only memory (OTPROM), electrically-erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM), or other optical disc memories, magnetic disk memories, tape memories, or any other medium that can be used to carry or store data and is computer-readable.

[0087] It should also be noted that the term "including", "comprising", or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, commodity, or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, commodity, or device. Without further limitations, an element defined by the statement "including one..." does not exclude the existence of another identical element in the process, method, commodity, or device including the element.

Claims

1. A method for detecting the insulation of automobile capacitors to ground, characterized in that: The insulation detection method comprises the following steps: A pulse transmitting module and a pulse receiving module are arranged in the automobile, the pulse transmitting module is used to transmit a high-frequency pulse signal to the capacitor of the automobile under test, and a pulse reflection signal received in the pulse receiving module is collected; Comparing the frequency domain characteristics between the high-frequency pulse signal and the pulse reflection signal to obtain the signal loss of the high-frequency pulse signal during the reflection process, and determining the reflection coefficient of the measured vehicle capacitor according to the signal loss and the capacity characteristics of the measured vehicle capacitor; Determine the impedance matching deviation between the vehicle capacitor and the ground loop, and determine the dielectric loss factor of the measured vehicle capacitor through the impedance matching deviation and the waveform distortion characteristics of the pulse reflection signal; The loss characteristics of the insulation of the vehicle capacitor to the ground are determined according to the dielectric loss factor and the reflection coefficient, and the insulation state of the vehicle capacitor to the ground is determined based on the loss characteristics.

2. A method for detecting the insulation of a vehicle capacitor to ground as claimed in claim 1, characterized in that: Comparing the frequency domain features between the high-frequency pulse signal and the pulse reflection signal to obtain the signal loss of the high-frequency pulse signal during the reflection process specifically includes: Performing frequency domain transformation on the high-frequency pulse signal to obtain a frequency domain amplitude spectrum and a phase spectrum of the input signal, and then determining an input power spectrum density of a frequency domain feature in the input signal through the frequency domain amplitude spectrum and the phase spectrum of the input signal; Performing frequency domain transformation on the pulse reflection signal to obtain a frequency domain amplitude spectrum and a phase spectrum of the output signal, and then determining the output power spectrum density of the frequency domain characteristics of the output signal through the frequency domain amplitude spectrum and the phase spectrum of the input signal; The input power spectrum density and the output power spectrum density are phase-separated and compared to obtain the signal loss of the high-frequency pulse signal during the reflection process.

3. A method for detecting the insulation of a vehicle capacitor to ground as claimed in claim 1, characterized in that: Determining the reflection coefficient of the measured vehicle capacitor by the signal loss and the capacitance characteristics of the measured vehicle capacitor specifically includes: Obtain standard impedance values ​​and capacity characteristics of automotive capacitors; Determining a characteristic impedance value of a vehicle capacitor through the capacity characteristic and the signal loss; The reflection coefficient of the measured vehicle capacitance is determined according to the characteristic impedance value and the standard impedance value.

4. A method for detecting the insulation of a vehicle capacitor to ground as claimed in claim 3, characterized in that: The high-frequency pulse signal is a high-frequency ultra-wideband pulse signal of Nyquist pulse shaping.

5. A method for detecting the insulation of a vehicle capacitor to ground as claimed in claim 1, characterized in that: Determining the impedance matching deviation between the vehicle capacitor and the ground return path specifically includes: Get the rated matching impedance value between the car capacitor and the ground loop; Collect the equivalent impedance between the car capacitor and the ground loop; The impedance matching deviation between the vehicle capacitor and the ground loop is determined by the equivalent impedance and the rated matching impedance value.

6. A method for detecting the insulation of a vehicle capacitor to ground as claimed in claim 1, characterized in that: Determining the dielectric loss factor of the measured vehicle capacitor by the impedance matching deviation and the waveform distortion characteristics of the pulse reflection signal specifically includes: Determine the dielectric loss angle of the measured vehicle capacitor based on the waveform distortion characteristics of the pulse reflection signal; The node loss angle and the impedance matching deviation are subjected to loss correlation matching to obtain the dielectric loss factor of the measured automotive capacitor.

7. A method for detecting the insulation of a vehicle capacitor to ground as claimed in claim 1, characterized in that: Determining the loss characteristics of the insulation of the automobile capacitor to the ground according to the dielectric loss factor and the reflection coefficient specifically includes: Construct a loss assessment algorithm based on an equivalent circuit model of automotive capacitors; Using the dielectric loss factor as a loss parameter in the loss evaluation algorithm; Using the reflection coefficient as an impedance matching parameter in the loss evaluation algorithm; The loss evaluation algorithm is used to evaluate the loss characteristics of the insulation between the automobile capacitor and the ground, and the loss characteristics of the insulation between the automobile capacitor and the ground are obtained.

8. A method for detecting insulation of automobile capacitor to ground as claimed in claim 1, characterized in that: Determining the insulation state of the automobile capacitor to the ground based on the loss characteristics specifically includes: Obtain a loss mapping table of the ground insulation of the automotive capacitor; The insulation state corresponding to the loss feature is selected from the loss mapping table as the insulation state of the automobile capacitor to the ground.

9. A method for detecting insulation of automobile capacitor to ground as claimed in claim 1, characterized in that: The pulse transmitting module is an ultra-wideband pulse generator.

10. A method for detecting the insulation of a vehicle capacitor to ground as claimed in claim 1, characterized in that: The pulse receiving module is a high-sensitivity radio frequency sampling receiver.

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