WO2020187044A1 - Circuit parameter detecting method and detecting device - Google Patents

Abstract

A circuit parameter detecting method, comprising: applying a preset excitation signal at an input end of a circuit to be tested, and acquiring one set of actual output data from an output end of said circuit (101); selecting from multiple sets of theoretical output data one set of theoretical output data of highest similarity with the set of actual output data (102); selecting, on the basis of preset correlations between the theoretical output data and parameter values, a set of parameter values corresponding to the selected set of theoretical output data, and making the parameter values in the acquired set of parameter values as detection values for circuit parameters of said circuit (103). Also related is a circuit parameter detecting device. The detecting method and the detecting device allow the detection of the circuit parameters to be free from interference of voltage changes in said circuit, thus increasing the accuracy of circuit parameter detection and reducing requirements on the detection environment.

Description

Method and device for detecting circuit parameters

cross reference

This application is cited in the Chinese Patent Application No. 201910217889.1 filed on March 21, 2019, entitled "Detection Method and Device for Circuit Parameters", which is fully incorporated into this application by reference.

Technical field

The embodiments of the present application relate to the technical field of circuit detection, in particular to a detection method and a detection device for circuit parameters.

Background technique

Electric vehicles instead of fuel vehicles have become a trend in the development of the automotive industry. The continued mileage, service life and safety of battery packs are particularly important to the use of electric vehicles. The power battery pack is one of the key components of electric vehicles, and the safety of its high voltage power must be one of the primary considerations of the power battery system. Therefore, the detection of the insulation performance of electric vehicles is an essential part of the design.

The moment the electric vehicle starts, the voltage of the battery pack will fluctuate. The reason is that its inverter is working. The inverter is composed of an insulated gate bipolar transistor IGBT, and its on-off frequency interference is high-frequency interference compared to the low-frequency injection method. In addition, in-vehicle electronic and electrical systems will more or less produce electromagnetic interference, which may also interfere with low-frequency injection signals. The electromagnetic interference generated by modern automobile electronic products is stronger and higher in frequency than before. Due to the continuous improvement of the electronic level of automobiles, the electromagnetic environment of vehicles has become more and more severe, so it is extremely necessary to process the sampled signals.

For the low-frequency AC injection method, an isolation capacitor is connected between the high voltage and the low voltage. In the static state, when the battery pack voltage does not fluctuate, because the capacitor has the function of blocking the direct current, the high voltage will affect the low voltage. There will be an impact, but when the IGBT is working, it will cause the battery pack voltage to fluctuate, so that the high-voltage signal is coupled to the low-voltage side, and the low-voltage side signal is interfered. The commonly used processing strategies at this stage are: sampling and filtering the AC signal, and finding the maximum and minimum values, or finding the amplitude and phase of the input signal and output signal, and then calculating the insulation resistance value through formulas.

The inventor found that there are at least the following problems in the prior art: in the existing low-frequency AC injection method for measuring insulation resistance, due to the influence of parasitic parameters in the circuit, and the battery pack voltage during the driving of the electric vehicle will be relatively large. Fluctuations cause interference to AC signals. These interferences will cause the interference to be amplified when the formula is used to calculate, and ultimately affect the calculation of the insulation resistance, resulting in an error in the calculation of the insulation resistance. Therefore, most equipment that performs insulation detection through AC signal injection requires a stable battery pack voltage to calculate the insulation resistance of electric vehicles. This additional condition will limit the use of insulation detection and reduce performance.

Application content

The purpose of the embodiments of this application is to provide a detection method and detection device for circuit parameters, so that the detection of circuit parameters is not interfered by voltage changes in the circuit to be tested, which improves the accuracy of circuit parameter detection and reduces the impact on the detection environment. Requirements.

In order to solve the above technical problem, the embodiment of the present application provides a method for detecting circuit parameters, including: applying a preset excitation signal to the input terminal of the circuit to be tested, and obtaining a set of signals from the output terminal of the circuit to be tested Actual output data; from the preset multiple sets of theoretical output data, select the set of theoretical output data with the highest similarity to this set of actual output data; according to the preset correspondence between the theoretical output data and parameter values, obtain the selected A set of parameter values corresponding to this set of theoretical output data, and each parameter value in the obtained set of parameter values is used as a detection value of each circuit parameter of the circuit to be tested.

The embodiment of the present application also provides a circuit parameter detection device, including: an excitation signal application module for applying a preset excitation signal at the input end of the circuit to be tested; an output data acquisition module for obtaining data from all The output terminal of the circuit under test obtains a set of actual output data; the similarity judgment module is used to select a set of theoretical output data with the highest similarity to this set of actual output data from the preset sets of theoretical output data; The value obtaining module is used to obtain a set of parameter values corresponding to the selected set of theoretical output data according to the preset correspondence between theoretical output data and parameter values, and use each parameter value in the set of obtained parameter values as The detection value of each circuit parameter of the circuit to be tested; a storage module for storing the corresponding relationship.

In the embodiment of the present application, when a certain excitation signal is applied to the input terminal of the circuit to be tested, the actual output data of the circuit to be tested is only related to the parameter values of the circuit to be tested; therefore, as long as the theoretical output data and parameters are preset With the corresponding relationship of values, it is possible to obtain a set of theoretical output data with the highest similarity to the actual output data when the actual output data of the circuit to be tested is known, and determine the parameter values of the circuit to be tested according to the above corresponding relationship; The detection of circuit parameters is not interfered by voltage changes in the circuit to be tested, and the accuracy of circuit parameter detection and the applicable environment are improved.

The setting method of the corresponding relationship is: setting multiple sets of parameter values for each circuit parameter of the circuit to be tested; performing multiple simulations based on the equivalent circuit model of the circuit to be tested and the multiple sets of parameter values; In each simulation, the equivalent circuit model is configured with a set of parameter values, the excitation signal is applied to the input end of the equivalent circuit model, and a set of theoretical outputs are obtained from the output end of the equivalent circuit model Data; multiple sets of theoretical output data obtained from multiple simulations and the multiple sets of parameter values establish the corresponding relationship. This embodiment provides a method for presetting the correspondence between multiple sets of theoretical output data and the multiple sets of parameter values.

The obtaining a set of theoretical output data from the output end of the equivalent circuit model includes: sampling the output end of the equivalent circuit model to obtain a set of theoretical sampling data; extracting the set of theoretical sampling data As the theoretical output data; the obtaining a set of actual output data from the output terminal of the circuit under test includes: sampling the output terminal of the circuit under test, and obtaining a set of actual output data Sampling data; extract the characteristic data of this set of actual sampling data as the actual output data. In this embodiment, feature data extraction is performed on the sampled data obtained by direct sampling, and the extracted feature data is used as the output data. Compared with directly storing the sampled data and using the sampled data for similarity judgment, the amount of data storage can be reduced. And the burden of data processing when judging similarity.

The sampling data includes a plurality of sampling values arranged in the order of acquisition time, and the characteristic data is extracted by successively taking the difference of two adjacent sampling values, and using the obtained several difference values as the characteristic data. This embodiment provides a specific implementation method for extracting characteristic data, which is simple and convenient, and can reduce the data storage amount by nearly half.

The excitation signal is a square wave signal; the consistency of each input can be controlled very conveniently.

Description of the drawings

One or more embodiments are exemplified by the pictures in the corresponding drawings. These exemplified descriptions do not constitute a limitation on the embodiments. Elements with the same reference numbers in the drawings are represented as similar elements. Unless otherwise stated, the figures in the attached drawings do not constitute a limitation of scale.

Fig. 1 is a flowchart of a method for detecting circuit parameters according to a first embodiment of the present application;

2A is a circuit diagram of a circuit applied by the detection method of the first embodiment of the present application;

Fig. 2B is an equivalent circuit diagram of the circuit of Fig. 2A;

Figure 2C is a simplified equivalent circuit diagram based on Figure 2B;

Fig. 3 is a flowchart of a setting manner of correspondence relations in the first embodiment of the present application;

FIG. 4 is a specific flowchart of the setting method of the corresponding relationship in FIG. 3;

FIG. 5 is a specific flow chart of a setting manner of a correspondence relationship in the second embodiment of the present application;

FIG. 6 is a specific flowchart of a method for detecting circuit parameters according to a second embodiment of the present application;

Fig. 7 is a block diagram of a circuit parameter detection device according to a third embodiment of the present application;

Fig. 8 is a block diagram of a circuit parameter detection device according to a fourth embodiment of the present application.

Specific embodiment

In order to make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the various embodiments of the present application will be described in detail below in conjunction with the accompanying drawings. However, a person of ordinary skill in the art can understand that in each embodiment of the present application, many technical details are proposed for the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solution claimed in this application can be realized. The division of the following embodiments is for convenience of description, and should not constitute any limitation to the specific implementation manner of the present application, and the various embodiments may be combined with each other without contradiction.

The first embodiment of the present application relates to a method for detecting circuit parameters. The specific process is shown in Figure 1, including:

Step 101: Apply a preset excitation signal to the input terminal of the circuit under test, and obtain a set of actual output data from the output terminal of the circuit under test.

Step 102: Select a group of theoretical output data with the highest similarity to this group of actual output data from a plurality of groups of theoretical output data.

Step 103: Obtain a set of parameter values corresponding to the selected set of theoretical output data according to the preset correspondence between the theoretical output data and the parameter values, and use each parameter value in the obtained set of parameter values as the circuit to be tested The detection value of each circuit parameter.

Compared with the prior art, in the embodiment of the present application, when a certain excitation signal is applied to the input terminal of the circuit to be tested, the actual output data of the circuit to be tested is only related to the parameter value of the circuit to be tested; Assuming the correspondence between the theoretical output data and the parameter values, it is possible to obtain a set of theoretical output data with the highest similarity to the actual output data when the actual output data of the circuit to be tested is known, and determine the to-be-tested according to the above correspondence The parameter value of the circuit; so that the detection of the circuit parameter is not interfered by the voltage change in the circuit to be tested, and the accuracy of the circuit parameter detection and the applicable environment are improved.

The implementation details of the circuit parameter detection method of this embodiment will be described in detail below. The following content is only provided for ease of understanding and is not necessary for implementing this solution.

The circuit parameter detection method of this embodiment can be applied to the insulation performance detection of electric vehicles. The circuit shown in FIG. 2A includes a high-voltage side and a low-voltage side; the high-voltage side is the circuit to be tested in this embodiment, including the electric vehicle The low-voltage side of the battery pack includes an insulation detection circuit 22; it should be noted that FIG. 2A only shows the battery unit 21 in the battery pack, but does not show the complete battery pack. Among them, Rp and Rn respectively represent the positive and negative insulation resistance of the battery pack, and Cp and Cn represent the Y capacitance of the battery pack. In the insulation detection circuit 22, the signal generator 221 is connected to the voltage dividing sampling resistor R1 through the boost circuit 222, and is used to apply an excitation signal to the input terminal A of the circuit to be tested; the first sampling circuit 223 passes through the first voltage follower circuit 224 is connected to the voltage dividing sampling resistor R1 and is used for sampling from the position of point A; the second sampling circuit 225 is connected to the isolation capacitor C1 through the second voltage follower circuit 226 and is used for sampling from the position of point B. The processor MCU is used to control the signal generator 221 and process the data collected by the first collection circuit 223 and the second collection circuit 225. The specific structure of the insulation detection circuit 22 is similar to the insulation detection circuit in the prior art that uses the low-frequency AC injection method to calculate the insulation resistance of the battery pack, and will not be described in detail.

It should be noted that although point A and point B are not in the circuit to be tested, because the battery pack of the electric vehicle is located on the high-voltage side, the excitation signal and the output data obtained from the output terminal must be isolated by the isolation capacitor C1. It is performed on the low-voltage side, and the voltage divider sampling resistor R1 needs to be used to divide the voltage of the circuit under test in the detection and sampling. Therefore, for ease of description, point A is referred to as the input of the circuit under test in this embodiment and subsequent embodiments. Terminal, point B is called the output terminal of the circuit under test.

Figure 2B is an equivalent circuit diagram of the circuit of Figure 2A, where Rnp represents the resistance of Rp and Rn in parallel, and Cnp represents the capacitance of Cp and Cn in parallel. In this embodiment, the circuit parameters of the circuit to be tested include insulation Resistor Rnp and Y capacitor Cnp.

It should be noted that, in this embodiment, the sampling period of the output data from the output terminal B needs to be synchronized with the input period of the excitation signal of the input terminal A. Since the excitation signal generated by the signal generator 221 and the excitation signal actually input to the input terminal A of the circuit to be tested may have errors in time, and the regularity of the excitation signal may not be very good, therefore, the first sampling circuit 223 controls the input terminal A The sampled data obtained by sampling can be used as a reference object for time synchronization of the output data obtained from the output terminal; however, this embodiment is not limited to this, the excitation signal generated by the signal generator 221 and the actual input to the circuit under test input When the excitation signal of terminal A has no time error and the regularity of the excitation signal is good, the first sampling circuit 223 may not be required to sample the input terminal A, and the sampling of the output data can be preset according to the input period of the excitation signal cycle.

The design idea of the circuit parameter detection method of this embodiment is that when a certain input signal is injected into the circuit to be tested, the output signal is only related to the circuit parameter of the circuit to be tested; then according to the corresponding relationship between the output signal and the circuit parameter , You can determine the unknown circuit parameters in the circuit under test when the output signal is known.

The following is an analysis and explanation of the feasibility of the above design ideas. Fig. 2C is a simplified equivalent circuit diagram based on Fig. 2B. The following description is based on Fig. 2C. The excitation signal applied at the input terminal A of the equivalent circuit of the circuit under test is represented by Ua. The output signal obtained by the output terminal B of the effect circuit is represented by Ub, where Ub represents the output signal collected by the sampling circuit 225; the circuit parameters of the circuit to be tested include insulation resistance Rnp and Y capacitance Cnp. The specific analysis is as follows.

According to the law of partial pressure of resistance:

Carrying out the Laplace transform of the above formula can get the transfer function corresponding to the circuit as follows:

Arrange the transfer function to get:

A=C1·Rnp+Cnp·Rnp

B=C1·Cnp·R1·Rnp

C=C1·R1+C1·Rnp+Cnp·Rnp

A, B, and C are three coefficients. Since C1 and R1 in the above formula respectively represent the capacitance value of the jumper capacitor and the resistance value of the voltage divider sampling resistor, they are all inherent parameters, so the transfer function G(s) of the circuit is only Related to Rnp, Cnp. Draw the following equation,

A1=C1*Rnp1+Cnp1*Rnp1

A2=C1*Rnp2+Cnp2*Rnp2

B1=C1*Cnp1*R1*Rnp1

B2=C1*Cnp2*R1*Rnp2

Assuming that there are Cnp1, Rnp1 and Cnp2, Rnp2 makes the corresponding transfer function G1(s) and G2(s) parameters equal (Cnp≠0, Rnp≠0), that is, A1=A2, B1=B2. Simplifying the above formula can be obtained: C1*Rnp1=C1*Rnp2, that is, if the parameters of the two transfer functions are equal, then the corresponding Rnp must be equal, and Cnp must also be equal.

Then, if Rnp and Cnp in the circuit of Fig. 2C change, the corresponding transfer function parameters must change. That is, for the same excitation signal, if the parameters of Rnp and Cnp in the circuit of Fig. 2C are not equal, the output signals are also not equal.

From the above analysis, it can be concluded that for different circuits under test, when the excitation signal is the same, the output signal is only related to the circuit parameters of the circuit under test; that is, if the excitation signal is unchanged, if the circuit is known The corresponding relationship between the parameter and the output signal, then the circuit parameter corresponding to the excitation circuit can be determined according to the collected output signal; thus, the detection of the circuit parameter is not affected by the voltage change on the high voltage side of the circuit.

Based on the foregoing principles, the setting method of the correspondence between theoretical output data and parameter values in this embodiment can be the following process. Please refer to FIG. 3, which specifically includes the following steps:

Step 301: Set multiple sets of parameter values for each circuit parameter of the circuit to be tested.

Step 302: Perform multiple simulations based on the equivalent circuit model of the circuit to be tested and multiple sets of parameter values; in each simulation, use a set of parameter values to configure the equivalent circuit model, and apply an excitation signal at the input of the equivalent circuit model. And get a set of theoretical output data from the output terminal of the equivalent circuit model.

Step 303: Establish a correspondence relationship between multiple sets of theoretical output data obtained from multiple simulations and multiple sets of parameter values.

Wherein, the excitation signal applied in the simulation stage in step 302 is consistent with the excitation signal applied in the actual detection in step 101.

It should be noted that steps 101 to 103 are the actual detection process, and steps 301 to 303 are the setting process of the correspondence between theoretical output data and parameter values. These two processes can be executed separately and can be executed by different execution subjects ; That is, the setting process of the corresponding relationship can be pre-executed by the laboratory electronic equipment and the corresponding relationship is obtained; the corresponding relationship is preselected and stored in the actual testing device, and the actual testing device executes the actual testing process based on the corresponding relationship Obtain the detection value of each circuit parameter of the device under test. However, this embodiment does not impose any limitation on this. The setting process of the correspondence relationship and the actual detection process can also be executed by the same electronic device, as long as the setting process of the correspondence relationship is executed before the actual detection process. .

In an example, as shown in Figure 4, step 301 includes the following sub-steps:

In sub-step 3011, based on the preset value range of each circuit parameter and the value method corresponding to each circuit parameter, several parameter values are set for the circuit parameters.

In sub-step 3012, several parameter values of each circuit parameter are arranged and combined, and multiple sets of parameter values are generated; wherein, each set of parameter values includes a parameter value of each circuit parameter.

The circuit parameter detection method of this embodiment can be applied to a circuit parameter detection device. In the detection device, the value method of several parameter values of Rnp and the value method of several parameter values of Y capacitor can be preset; , The value of the n parameter values of Rnp can be expressed as:

Rnp(k1)=(1+A _Rnp ) ^k1 k1=0,1,2,..., n formula (1)

The value method of the m parameter values of Cnp can be expressed as:

Cnp(k2)=0.2*(1+A _Cnp ) ^k2 k2=0,1,2,...,m Formula (2)

Among them, A _Rnp represents the measurement error (precision) of _Rnp ; A _cnp represents the measurement error (precision) of Cnp, and both n and m are integers greater than 0. It should be noted that in formula (2), the significance of the value of 0.2 is that for the insulation detection circuit, when the Y capacitance of the whole vehicle is 0.2μF (k2=0) or less, the value of the insulation resistance is The detection has no effect, so the value of Y capacitor starts from 0.2μF. Among them, the unit of Rnp in formula (1) is kΩ, and the unit of Cnp in formula (2) is μF.

From the above formula (1), the formula (2), Rnp measurement error A _Rnp, Cnp A _cnp measurement error can be set according to actual needs. In this embodiment, the measurement error Rnp A _Rnp, Cnp A _cnp measurement error is set up in advance by the designer and stored in the detection means, for example, _{A Rnp = 0.15, A cnp =} 1. It should be noted that since the insulation detection circuit 22 does not require high accuracy of the Y capacitor, the error of the Y capacitor can be selected to 100%, that is, A _cnp =1.

Therefore, in this embodiment, the parameter value of Rnp can be selected according to the following formula: Rnp(k1)=1000*1.15^k1, k1=0,1,2,3...n; the parameter of Cnp The value can be taken according to the following formula: Cnp(k2)=0.2*2^k2, k2=0,1,2,3,...,m.

In this embodiment, the value range and value method of each circuit parameter can be set in the detection device in advance by the user. For example, the value range of Rnp can be 1kOhm~3MOhm, and the value range of Cnp can be 0.2μF. ~3.2μF.

For simplicity of description in this embodiment, n=4 and m=4 are taken, that is, the first 5 parameter values of Rnp (k1 is 0 to 4) and the 5 parameter values of Cnp (k2 is 0 to 4) To illustrate, as shown in Table 1 below, the abscissa is the parameter value of Rnp, and the ordinate is the parameter value of Cnp.

Table 1

k1

0

1

2

3

4

k2	Cnp\Rnp	1000	1150	1322.5	1520.875	1749.006
0	0.2	G00	G01	G02	G03	G04
1	0.4	G10	G11	G12	G13	G14
2	0.8	G20	G21	G22	G23	G24
3	1.6	G30	G31	G32	G33	G34
4	3.2	G40	G41	G42	G43	G44

Among them, in the value formula of Rnp, when the values of k1 are 0, 1, 2, 3, 4, the values of the 5 parameters of Rnp are 1000, 1150, 1322.5, 1520.875, and 1749.006 respectively; the value of Cnp In the formula, when the values of k2 are 0, 1, 2, 3, and 4, the 5 parameter values of Cnp are 0.2, 0.4, 0.8, 1.6, and 3.2, respectively.

Arrange and combine the 5 parameter values of Rnp and the 5 parameter values of Cnp, there can be 5*5=25 combinations, that is, 25 groups of parameter values are formed, and 25 transfer functions G00～G44 are obtained; among them, each group of parameters The value can uniquely determine a transfer function.

It should be noted that in the above example, the value range of Rnp and Cnp can be set as required; the value formula of the parameter value of Rnp and Cnp can also be set as required, and the value interval of the parameter value of Rnp is larger. Smaller, the smaller the interval between Cnp parameter values, the more accurate, and the larger the number of Rnp and Cnp parameter values, the more accurate.

The specific implementation of the above step 301 is only an example and not limited to this; the designer can also directly set each group of parameter values.

In step 302, the number of simulations is equal to the number of groups of parameter values. For example, if 25 groups of parameter values are formed in the above example, 25 simulations are required. In each simulation, a set of parameter values are substituted (for example, if Rnp=1000, Cnp=0.2 is substituted for this set of parameter values, the value of the insulation resistance Rnp of the equivalent circuit model is set to 1000, and the value of Cnp Set to 0.2), and apply the same excitation signal Ua to the input terminal A of the equivalent circuit model in each simulation, and collect theoretical output data from the output terminal B of the equivalent circuit model. The excitation signal is shown in Figure 2C The input signal Ua of is represented, and the theoretical output data is represented by the output signal Ub in Figure 2C. The theoretical output data corresponding to a set of parameter values can be obtained in each simulation; after multiple simulations, the obtained sets of theoretical output data correspond to the sets of parameter values respectively.

As shown in Table 2 below, it is the 25 sets of theoretical output data DataArray00～DataArray44 corresponding to the 25 sets of parameter values in the above example.

Table 2

	k1	0	1	2	3	4
k2	Cnp\Rnp	1000	1150	1322.5	1520.875	1749.006
0	0.2	DataArray00	DataArray01	DataArray02	DataArray03	DataArray04
1	0.4	DataArray10	DataArray11	DataArray12	DataArray13	DataArray14
2	0.8	DataArray20	DataArray21	DataArray22	DataArray23	DataArray24
3	1.6	DataArray30	DataArray31	DataArray32	DataArray33	DataArray34
4	3.2	DataArray40	DataArray41	DataArray42	DataArray43	DataArray44

In this embodiment, the output terminal of the circuit to be tested is sampled to obtain theoretical sampling data, and the theoretical sampling data is used as the theoretical output data; wherein the sampling data includes multiple sampling values, that is, multiple theoretical sampling values are taken as A set of theoretical output data.

The excitation signal in this embodiment is a square wave signal, the period of the square wave signal is, for example, 500 ms, and the sampling period of the output terminal is, for example, 10 ms. The square wave signal can easily control the consistency of each input, that is, the excitation signal is relatively stable, and avoid the influence of the instability of the excitation signal on the output signal; however, it is not limited to this, if other waveforms can guarantee each input For consistency, you can also select other waveforms as input.

In step 101, during the operation of the electric vehicle, the input terminal of the circuit to be tested is supplied with the same excitation signal Ua as in the simulation, and the output terminal is sampled to obtain the actual sampled data, and the actual sampled data is used as Actual output data; among them, the sampled data includes multiple sampled values, that is, the actual multiple sampled values are regarded as a set of actual output data.

In step 102 and step 103, the group of actual output data and each group of theoretical output data are similarly judged, and the group of theoretical output data with the highest degree of similarity to the group of actual output data is selected, and according to the preset Correspondence: Obtain a set of parameter values corresponding to the selected set of theoretical output data, and distribute the two parameter values (Rnp parameter value and Cnp parameter value) of the obtained set of parameter values to the circuit under test The detection value of the insulation resistance Rnp and the detection value of the Y capacitor Cnp; among them, the parameter value of Rnp in this set of parameter values is used as the detection value of the insulation resistance Rnp, and the parameter value of Cnp is used as the detection value of the Y capacitor Cnp.

Among them, the similarity can be judged by calculating the cosine similarity of the actual output data and the theoretical output data. The cosine similarity operation is to evaluate the similarity of the two vectors by calculating the cosine of the angle between them. In this embodiment, the two vectors are the actual output data (the actual multiple sample values) and the theoretical output data (the theoretical multiple sample values). Calculate the cosine of the included angle between the actual output data and each group of theoretical output data. The smaller the cosine value of the included angle, the higher the similarity. Therefore, the group of theoretical output data with the smallest cosine value of the calculated included angle and the group The actual output data has the highest degree of similarity. Among them, the specific calculation method of the cosine similarity should be known to those skilled in the art, and will not be repeated here.

The second embodiment of the present application relates to a method for detecting circuit parameters. The second embodiment is substantially the same as the first embodiment, and the main difference is that: in the second embodiment of the present application, the feature data extraction operation is performed on the sampled data, and the extracted feature data is used as the output data.

Figures 5 and 6 are flowcharts of the circuit parameter detection method according to the second embodiment of the present application; the specific steps are as follows.

In Figure 5,

Step 401: Set multiple sets of parameter values for each circuit parameter of the circuit to be tested; Step 401 is similar to Step 301 in the first embodiment, and will not be repeated here.

Step 402: When performing simulation based on the equivalent circuit model of the circuit to be tested and multiple sets of parameter values, apply a preset excitation signal to the input terminal of the equivalent circuit model, sample the output terminal of the equivalent circuit model, and obtain a Set the theoretical sampling data; extract the characteristic data of the theoretical sampling data as the theoretical output data.

Step 403: Establish a corresponding relationship between multiple sets of theoretical output data obtained from multiple simulations and multiple sets of parameter values; step 403 is similar to step 303 in the first embodiment, and will not be repeated here.

In Figure 6,

Step 501: Apply an excitation signal to the input terminal of the circuit to be tested, sample the output terminal of the circuit to be tested, and obtain a set of actual sampling data, and extract the characteristic data of the actual sampling data as the actual output data .

Step 402 and step 302 are slightly different, and step 501 is slightly different from step 101; in this embodiment, the sample data obtained by direct sampling is not used as the output data, but the characteristic data is extracted from the output data, and the extraction The characteristic data as output data. The sampling data includes multiple sampling values arranged in the order of acquisition time. In one example, the feature data extraction method is to take the difference of two adjacent sampling values one by one, and use the obtained several differences as the feature data.

For example, in step 402, the theoretical multiple sample values include S0, S1, S2, S3, S4, S5, S6, S7, S8, S9, S10; feature data extraction is performed on the theoretical multiple sample values to extract The latter feature data includes S1-S0, S2-S1, S3-S2, S4-S3, S5-S4, S6-S5, S7-S6, S8-S7, S9-S8, S10-S9. In step 501, the actual multiple sample values include M0, M1, M2, M3, M4, M5, M6, M7, M8, M9, M10; feature data extraction is performed on the actual multiple sample values, and the extracted Feature data includes M1-M0, M2-M1, M3-M2, M4-M3, M5-M4, M6-M5, M7-M6, M8-M7, M9-M8, M10-M9.

Step 502: Select a set of theoretical output data with the highest similarity to the set of actual output data from a plurality of sets of theoretical output data. In this embodiment, the extracted feature data is used for similarity judgment. The specific similarity judgment is roughly the same as that in step 102, and will not be repeated here.

Step 503: According to the preset correspondence between the theoretical output data and the parameter values, obtain a set of parameter values corresponding to the selected set of theoretical output data, and use each parameter value in the obtained set of parameter values as the circuit to be tested The detection value of each circuit parameter. Step 503 is similar to step 103 in the first embodiment, and will not be repeated here.

The division of the steps of the various methods above is only for clarity of description. When implemented, it can be combined into one step or some steps can be split into multiple steps, as long as they include the same logical relationship, they are all within the protection scope of this patent. ; Adding insignificant modifications to the algorithm or process or introducing insignificant design, but not changing the core design of the algorithm and process are within the scope of protection of the patent.

The third embodiment of the present application relates to a circuit parameter detection device, as shown in FIG. 7, including:

The excitation signal applying module 701 is used to apply a preset excitation signal to the input terminal of the circuit under test 20.

The output data acquisition module 702 is configured to acquire a set of actual output data from the output terminal of the circuit under test 20.

The similarity judgment module 703 is used to select a group of theoretical output data with the highest similarity to this group of actual output data from a plurality of groups of theoretical output data.

The detection value obtaining module 704 is used to obtain a set of parameter values corresponding to the selected set of theoretical output data according to the preset corresponding relationship between the theoretical output data and the parameter values, and to obtain each parameter in the set of obtained parameter values The value is used as the detection value of each circuit parameter of the circuit under test.

The storage module 705 is configured to store the above-mentioned corresponding relationship.

Wherein, the excitation signal applying module 701 includes, for example, the signal generator 221 and the boost circuit 222 in FIG. 2A; the output data acquisition module 702 may include, for example, the first sampling circuit 223, the first voltage follower circuit 224, and the second sampling circuit 223 in FIG. 2A. The sampling circuit 225 and the second voltage follower circuit 226; the similarity judgment module 703 and the detection value acquisition module 704 can all be understood as a piece of program instructions, stored in the instruction memory, and the processor can execute each program instruction in the instruction memory to realize the above The function of each module; the processor may be, for example, the microprocessor MCU in FIG. 2A.

In this embodiment, the device for detecting circuit parameters further includes:

The parameter value setting module 706 is used to set multiple sets of parameter values for each circuit parameter of the circuit under test 20.

The simulation module 707 is configured to perform multiple simulations based on the equivalent circuit model of the circuit to be tested and the multiple sets of parameter values; in each simulation, a set of parameter values is used to configure the equivalent circuit model, and in the The input terminal of the equivalent circuit model applies the excitation signal, and a set of theoretical output data is obtained from the output terminal of the equivalent circuit model.

The correspondence relationship establishment module 708 is used to establish correspondence relationships between multiple sets of theoretical output data obtained from multiple simulations and multiple sets of parameter values.

It should be noted that the modules 701-705 correspond to the actual detection process, and the modules 706-708 correspond to the above-mentioned corresponding setting process; that is, the modules 701-705 can be integrated in an electronic device and can be brought to the detection site for treatment The modules 701 to 705 can be integrated in another electronic device, and the correspondence relationship between multiple sets of theoretical output data and the multiple sets of parameter values can be preset; wherein, the correspondence relationship establishment module 708 can be connected to The storage module 705, at this time, the established correspondence can be directly stored in the storage module 705 (wired transmission or wireless transmission is acceptable), or the correspondence establishment module 708 and the storage module 705 may not be connected, and the tester manually The corresponding relationship obtained in the relationship establishing module 708 is stored in the storage module 705. It should be noted that this embodiment does not impose any limitation on this, and the modules 701 to 708 can also be integrated in an electronic device.

It is not difficult to find that this embodiment is a system embodiment corresponding to the first embodiment, and this embodiment can be implemented in cooperation with the first embodiment. The related technical details mentioned in the first embodiment are still valid in this embodiment, and in order to reduce repetition, they will not be repeated here. Correspondingly, the related technical details mentioned in this embodiment can also be applied to the first embodiment.

It is worth mentioning that the modules involved in this embodiment are all logical modules. In actual applications, a logical unit can be a physical unit, a part of a physical unit, or multiple The combination of physical units is realized. In addition, in order to highlight the innovative part of the present application, this embodiment does not introduce a unit that is not closely related to solving the technical problem proposed by the present application, but this does not indicate that there are no other units in this embodiment.

The fourth embodiment of the present application relates to a device for detecting circuit parameters. The fourth embodiment is substantially the same as the third embodiment, with the main difference being: in the fourth embodiment of the present application, the feature data extraction operation is performed on the sampled data, and the extracted feature data is used as the output data. Please refer to Figure 8.

The simulation module 707 obtains theoretical output data from the output terminal of the equivalent circuit model. Specifically, the simulation module 707 samples the output terminal of the equivalent circuit model and obtains theoretical sampling data; the simulation module 707 extracts the characteristics of the theoretical sampling data Data as theoretical output data.

The output data acquisition module 702 includes a sampling circuit sub-module 7021 and a characteristic data extraction sub-module 7022; the sampling circuit sub-module 7021 is used to sample the output terminal of the circuit to be tested and obtain the actual sample data; the characteristic data extraction sub-module 7022 is used to The characteristic data of the actual sampling data is extracted as the actual output data.

Among them, the sampling circuit sub-module 7021 can be realized by the hardware circuit as shown in the second sampling circuit 225 and the second voltage follower circuit 226 in FIG. 2A; the characteristic data extraction sub-module 7022 can be understood as a section of program instructions, as shown in FIG. The MCU in 2A executes to realize its function, and it can also be realized by a specific hardware circuit, which is not limited in this embodiment.

Since the second embodiment corresponds to this embodiment, this embodiment can be implemented in cooperation with the second embodiment. The related technical details mentioned in the second embodiment are still valid in this embodiment, and the technical effects that can be achieved in the second embodiment can also be achieved in this embodiment. In order to reduce repetition, details are not repeated here. Correspondingly, the related technical details mentioned in this embodiment can also be applied to the second embodiment.

Those of ordinary skill in the art can understand that the above-mentioned embodiments are specific embodiments for realizing the application, and in actual applications, various changes can be made in form and details without departing from the spirit of the application. And scope.

Claims (12)

1. A method for detecting circuit parameters includes:

   Applying a preset excitation signal to the input terminal of the circuit under test, and obtaining a set of actual output data from the output terminal of the circuit under test;

   Select a set of theoretical output data with the highest similarity to this set of actual output data from the preset multiple sets of theoretical output data;

   According to the preset correspondence between the theoretical output data and the parameter values, obtain a set of parameter values corresponding to the selected set of theoretical output data, and use each parameter value in the obtained set of parameter values as the value of the circuit to be tested The detection value of each circuit parameter.
2. The method for detecting circuit parameters according to claim 1, wherein the setting mode of the corresponding relationship is:

   Setting multiple sets of parameter values for each circuit parameter of the circuit to be tested;

   Perform multiple simulations based on the equivalent circuit model of the circuit under test and the multiple sets of parameter values; in each simulation, a set of parameter values is used to configure the equivalent circuit model, and the equivalent circuit model is input Apply the excitation signal to the terminal, and obtain a set of theoretical output data from the output terminal of the equivalent circuit model;

   The corresponding relationship is established between multiple sets of theoretical output data obtained by multiple simulations and the multiple sets of parameter values.
3. The method for detecting circuit parameters according to claim 2, wherein the obtaining a set of theoretical output data from the output terminal of the equivalent circuit model comprises: sampling the output terminal of the equivalent circuit model, and Obtain a set of theoretical sampling data; extract the characteristic data of this set of theoretical sampling data as this set of theoretical output data;

   The obtaining a set of actual output data from the output terminal of the circuit to be tested includes: sampling the output terminal of the circuit to be tested to obtain a set of actual sampling data; extracting the characteristics of the actual sampling data Data as the actual output data.
4. The method for detecting circuit parameters according to claim 3, wherein the sampling data includes a plurality of sampling values arranged in the order of acquisition time, and the characteristic data is extracted by taking the difference of two adjacent sampling values successively , And use the obtained differences as the characteristic data.
5. The circuit parameter detection method according to claim 2, wherein said setting multiple sets of parameter values for each circuit parameter of the circuit to be tested specifically includes:

   Based on the preset value range of each circuit parameter and the value method corresponding to each circuit parameter, respectively setting several parameter values for the circuit parameter;

   The several parameter values of the circuit parameters are arranged and combined, and the multiple sets of parameter values are generated; wherein, each set of parameter values includes one parameter value of each circuit parameter.
6. The method for detecting circuit parameters according to claim 1, wherein each circuit parameter includes insulation resistance and Y capacitance of an electric vehicle.
7. The method for detecting circuit parameters according to claim 5, wherein each circuit parameter includes insulation resistance and Y capacitance of an electric vehicle;

   The value mode of the n parameter values of the insulation resistance value is:

   Rnp(k1)=(1+A _Rnp ) ^k1 k1=0,1,2,...,n

   The value method of the m parameter values of the Y capacitor is:

   Cnp(k2)=0.2*(1+A _Cnp ) ^k2 k2=0,1,2,...,m

   Wherein, Rnp represents the insulation resistance value, A _Rnp represents the measurement error of Rnp, Cnp represents the Y capacitance, A _cnp represents the measurement error of Cnp, and n and m are both integers greater than zero.
8. The method for detecting circuit parameters according to claim 1, wherein the excitation signal is a square wave signal.
9. A detection device for circuit parameters includes:

   An excitation signal applying module, used for applying a preset excitation signal to the input terminal of the circuit to be tested;

   An output data acquisition module for acquiring a set of actual output data from the output terminal of the circuit to be tested;

   The similarity judgment module is used to select a set of theoretical output data with the highest similarity to this set of actual output data from the preset sets of theoretical output data;

   The detection value obtaining module is used to obtain a set of parameter values corresponding to the selected set of theoretical output data according to the preset corresponding relationship between the theoretical output data and the parameter value, and to obtain each parameter value in the set of parameter values obtained As a detection value of each circuit parameter of the circuit to be tested;

   The storage module is used to store the corresponding relationship.
10. The circuit parameter detection device according to claim 9, wherein the detection device further comprises:

    The parameter value setting module is used to set multiple sets of parameter values for each circuit parameter of the circuit to be tested;

    The simulation module is used to perform multiple simulations based on the equivalent circuit model of the circuit to be tested and the multiple sets of parameter values; in each simulation, a set of parameter values is used to configure the equivalent circuit model, and in the Apply the excitation signal to the input terminal of the effective circuit model, and obtain a set of theoretical output data from the output terminal of the equivalent circuit model;

    The correspondence relationship establishment module is used to establish the correspondence relationship between multiple sets of theoretical output data obtained from multiple simulations and the multiple sets of parameter values.
11. The circuit parameter detection device according to claim 10, wherein the simulation module is used to obtain a set of theoretical output data from the output terminal of the equivalent circuit model, specifically, the simulation module is used to The output terminal of the equivalent circuit model is sampled, and a set of theoretical sampling data is obtained; and the characteristic data of the theoretical sampling data is extracted as the theoretical output data;

    The output data acquisition module includes a sampling circuit sub-module and a characteristic data extraction sub-module; the sampling circuit sub-module is used to sample the output terminal of the circuit to be tested and obtain a set of actual sampling data; the characteristic The data extraction sub-module is used to extract the characteristic data of this set of actual sampling data as the actual output data.
12. The circuit parameter detection device according to claim 10, wherein the parameter value setting module includes a value sub-module and a combination sub-module;

    The value sub-module is used to set a number of parameter values for the circuit parameters based on the preset value ranges of the circuit parameters and the value methods corresponding to the circuit parameters; the combinator The module is used to arrange and combine several parameter values of the circuit parameters, and generate the multiple groups of parameter values.

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