Insulation detection method and device, electronic equipment and storage medium

Abstract

The invention provides an insulation detection method and device, electronic equipment and a storage medium. The method comprises the following steps: acquiring a first voltage point and a second voltage point of a first insulation resistor and a second insulation resistor based on acquisition time; when the first switch and the second switch are both in an off state, processing based on the sampling time of each first voltage point and the corresponding voltage value, the first capacitance, the second capacitance, the first insulation resistance, the second insulation resistance and the battery pack voltage, and determining a corresponding first target parameter; when the first switch and the second switch are both in a closed state, processing based on the sampling time of each second voltage point and the corresponding voltage value, the first capacitor, the second capacitor, the first insulation resistance, the second insulation resistance, other resistors and the voltage of the battery pack, and determining a corresponding second target parameter; and determining resistance values of the first insulation resistor and the second insulation resistor based on the first target parameter and the second target parameter. And the accuracy of the measurement result is prevented from being influenced by other modes.

Description

Technical Field

[0001] This invention relates to the field of insulation testing technology, and in particular to an insulation testing method, apparatus, electronic device, and storage medium. Background Technology

[0002] Existing insulation testing methods mainly include the bridge method, which measures resistance using the bridge balance principle, and the low-frequency signal injection method. The principle of the low-frequency signal injection method is to inject a low-frequency signal into the high-voltage system of an electric vehicle and calculate the insulation resistance value by detecting the response of the signal in the system.

[0003] Because the components of the bridge circuit are easily affected by environmental factors such as temperature and electromagnetic fields, their resistance values ​​or other parameters may change, affecting the accuracy of the measurement results. Furthermore, this method calculates the insulation resistance based on the circuit in steady state, which results in a relatively long detection time. For the low-frequency signal injection method, various electromagnetic interference signals exist in the actual vehicle operating environment. These interference signals may affect the injection and detection of low-frequency signals, leading to inaccurate measurement results. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide an insulation testing method, apparatus, electronic device, and storage medium to solve the problem of inaccurate measurement results in the prior art.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0006] A first aspect of this invention discloses an insulation detection method applied to an insulation detection circuit, the insulation detection circuit including a first switch, a second switch, a first insulation resistor, a second insulation resistor, a first capacitor, a second capacitor, a battery pack voltage, and other resistors, the method comprising:

[0007] The data is collected based on the acquisition time, specifically the first voltage point of the first insulation resistance and the second insulation resistance when both the first switch and the second switch are open, and the second voltage point of the first insulation resistance and the second insulation resistance when both the first switch and the second switch are closed.

[0008] When both the first switch and the second switch are in the open state, the first target parameter is determined by processing based on the sampling time and corresponding voltage value of each first voltage point, the first capacitor, the second capacitor, the first insulation resistance, the second insulation resistance, and the battery pack voltage.

[0009] When both the first switch and the second switch are in the closed state, the sampling time T and the corresponding voltage value of each second voltage point, the first capacitor, the second capacitor, the first insulation resistance, the second insulation resistance, other resistances, and the battery pack voltage are processed to determine the corresponding second target parameter.

[0010] The resistance values ​​of the first insulation resistance and the second insulation resistance are determined based on the first target parameter and the second target parameter.

[0011] Optionally, when both the first switch and the second switch are in the open state, the first target parameter is determined based on the sampling time and corresponding voltage value of each first voltage point, the first capacitor, the second capacitor, the first insulation resistance, the second insulation resistance, and the battery pack voltage, including:

[0012] When both the first switch and the second switch are in the open state, the current in the insulation detection circuit flows through the first capacitor, the second capacitor, the first insulation resistance, the second insulation resistance, and the battery pack voltage.

[0013] Based on the first capacitor, the second capacitor, the first insulation resistance, the second insulation resistance, and the battery pack voltage, a first relationship between the capacitor, resistance, and voltage at time k is determined, where k is the current sampling time.

[0014] The first relational expression is processed based on the sampling time and corresponding voltage value of each first voltage point to obtain the first target parameter.

[0015] Optionally, the first relational expression is processed based on the sampling time and corresponding voltage value of each first voltage point to obtain the first target parameter, including:

[0016] For each first voltage point, if the first voltage point is the mth sampling, obtain the current sampling time and voltage value, as well as the voltage values ​​of the first voltage points in the previous m-1 samplings, where m is a positive integer greater than or equal to 2 and less than or equal to M.

[0017] Substituting the current sampling time k and voltage value, as well as the voltage value of the first voltage point in the previous m-1 times, into the first relational expression, we obtain the first relational expression corresponding to each first voltage point. The sampling time k belongs to the sampling time.

[0018] The first relational expression corresponding to each first voltage point is identified to determine the first target parameter.

[0019] Optionally, when both the first switch and the second switch are in the closed state, the corresponding second target parameter is determined based on the sampling time and corresponding voltage value of each second voltage point, the first capacitor, the second capacitor, the first insulation resistance, the second insulation resistance, other resistances, and the battery pack voltage, including:

[0020] When both the first switch and the second switch are closed, and the link between the first switch and the first resistor among the other resistors is closed, and the link between the second switch and the second resistor among the other resistors is closed, the current in the insulation detection circuit flows through the first capacitor, the second capacitor, the first insulation resistor, the second insulation resistor, the first and second resistors among the other resistors, and the battery pack voltage;

[0021] Based on the first capacitor, the second capacitor, the first insulation resistance, the second insulation resistance, the first resistance, the second resistance, and the battery pack voltage, a second relationship between the capacitor, resistance, and voltage at time k is determined, where k is the sampling time.

[0022] The second relation is processed based on the sampling time T and the corresponding voltage value of each second voltage point to obtain the second target parameter.

[0023] Optionally, the second relationship is processed based on the sampling time T and the corresponding voltage value of each second voltage point to obtain the second target parameter, including:

[0024] For each second voltage point, if the second voltage point is the nth sampling, obtain the current sampling time and voltage value, as well as the voltage value of the first voltage point in the previous n-1 samplings, where n is a positive integer greater than or equal to 2 and less than or equal to N;

[0025] Substituting the current sampling time k and voltage value, as well as the voltage value of the first voltage point in the previous n-1 times, into the second relational expression, we obtain the second relational expression corresponding to each second voltage point. The sampling time k belongs to the sampling time.

[0026] The second relational expression corresponding to each second voltage point is identified to determine the second target parameter.

[0027] Optionally, determining the resistance values ​​of the first insulation resistance and the second insulation resistance based on the first target parameter and the second target parameter includes:

[0028] The resistance value of the first insulation resistance is calculated based on the first parameter in the first target parameters and the first parameter in the second target parameters;

[0029] The resistance value of the second insulation resistance is calculated based on the second parameter in the first target parameter and the second parameter in the second target parameter.

[0030] Optional, also includes:

[0031] Determine whether the resistance value of the first insulation resistor is less than a first threshold and whether the resistance value of the second insulation resistor is less than a second threshold;

[0032] If both are true, it is determined that the insulation detection circuit has an insulation fault.

[0033] A second aspect of this invention discloses an insulation detection device applied to an insulation detection circuit. The insulation detection circuit includes a first switch, a second switch, a first insulation resistor, a second insulation resistor, a first capacitor, a second capacitor, a battery pack voltage, and other resistors. The device includes:

[0034] The acquisition unit is used to acquire, based on the acquisition time, the first voltage point of the first insulation resistance and the second insulation resistance when both the first switch and the second switch are open, and the second voltage point of the first insulation resistance and the second insulation resistance when both the first switch and the second switch are closed;

[0035] The first processing unit is configured to perform circuit processing based on the sampling time and corresponding voltage value of each first voltage point, the first capacitor, the second capacitor, the first insulation resistance, the second insulation resistance, and the battery pack voltage when both the first switch and the second switch are in the off state, and to determine the corresponding first target parameter.

[0036] The second processing unit is used to determine the corresponding second target parameter based on the sampling time and corresponding voltage value of each second voltage point, the first capacitor, the second capacitor, the first insulation resistance, the second insulation resistance, other resistances, and the battery pack voltage when both the first switch and the second switch are in the closed state.

[0037] The determining unit is used to determine the resistance values ​​of the first insulation resistance and the second insulation resistance based on the first target parameter and the second target parameter.

[0038] A third aspect of the present invention discloses an electronic device, the electronic device including a processor and a memory, the memory being used to store program code and data for data generation, and the processor being used to call program instructions in the memory to execute an insulation detection method as described in any of the first aspects of the present invention.

[0039] A fourth aspect of the present invention discloses a storage medium comprising a stored program, wherein, when the program is executed, it controls the device containing the storage medium to perform a data insulation detection method as described in any of the first aspects of the present invention.

[0040] Based on the above embodiments of the present invention, an insulation detection method, device, electronic device, and storage medium are provided, which are applied to an insulation detection circuit. The insulation detection circuit includes a first switch S1, a second switch S2, and a first insulation resistor. Second insulation resistance First capacitor Second capacitor Battery pack voltage In addition to other resistances, the method includes: acquiring the first insulation resistance when both the first switch S1 and the second switch S2 are open based on the acquisition time. Second insulation resistance The first voltage point, and the first insulation resistance when both the first switch S1 and the second switch S2 are closed. Second insulation resistance The second voltage point; when both the first switch S1 and the second switch S2 are in the open state, based on the sampling time T and the corresponding voltage value of each first voltage point, the first capacitor Second capacitor First insulation resistance Second insulation resistance and battery pack voltage Circuit processing is performed to determine the corresponding first target parameter; when both the first switch S1 and the second switch S2 are in the closed state, based on the sampling time T and the corresponding voltage value of each second voltage point, the first capacitor... Second capacitor First insulation resistance Second insulation resistance Other resistors, and battery pack voltage The process involves determining the corresponding second target parameter; based on the first target parameter and the second target parameter, the resistance values ​​of the first insulation resistance and the second insulation resistance are determined. In this embodiment of the invention, the first switch... Second switch When disconnected, based on the sampling time T and corresponding voltage value of each first voltage point, the equation expression for the current in the circuit is determined, along with the first capacitor, second capacitor, first insulation resistance, second insulation resistance, and battery pack voltage, thereby determining the first target parameter; then, at the first switch... Second switch When closed, based on the sampling time T and corresponding voltage value of each second voltage point, the first capacitor, the second capacitor, the first insulation resistance, the second insulation resistance, and other resistances; the insulation resistance value can be calculated based on the unknown parameters, namely the first target parameter and the second target parameter. This method avoids other factors affecting the accuracy of the measurement results and avoids other interference signals, thus enabling the detection of potential insulation faults in a shorter time. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of a simplified insulation detection circuit according to an embodiment of the present invention;

[0043] Figure 2 This is a schematic flowchart illustrating an insulation detection method according to an embodiment of the present invention;

[0044] Figure 3 This is a schematic diagram illustrating the insulation testing process according to an embodiment of the present invention;

[0045] Figure 4 This is a schematic flowchart illustrating another insulation detection method according to an embodiment of the present invention;

[0046] Figure 5 This is a schematic diagram of an insulation detection device according to an embodiment of the present invention. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0049] It should be noted that the descriptions involving "first," "second," etc., in this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0050] In this application, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0051] See Figure 1 This is a schematic diagram of a simplified insulation detection circuit according to an embodiment of the present invention.

[0052] The insulation detection circuit includes battery pack voltage. The first capacitor, namely the positive Y capacitor. The second capacitor, namely the negative Y capacitor. The first insulation resistance, i.e., the positive electrode insulation resistance. The second insulation resistance, i.e., the negative electrode insulation resistance. First switch S1, second switch S2, and other resistors;

[0053] The other resistors include a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4;

[0054] The first capacitor Insulation resistance with the positive electrode Parallel connection, the second capacitor Insulation resistance with negative electrode in parallel;

[0055] The first capacitor and the positive electrode insulation resistance One end connected in parallel with the second capacitor Insulation resistance of negative electrode Connect one end in parallel;

[0056] The first capacitor and the positive electrode insulation resistance The other end of the parallel connection is connected to the voltage of the battery pack respectively. One end of the switch is connected to one end of the first switch S1;

[0057] The second capacitor Insulation resistance of negative electrode The other end of the parallel connection is connected to the voltage of the battery pack respectively. The other end is connected to one end of the second switch S2.

[0058] The first resistor R1 and the third resistor R3 are connected in parallel, and the second resistor R2 and the fourth resistor R4 are connected in parallel.

[0059] The first resistor R1 and the third resistor R3 can be connected to the first switch S1 respectively; the second resistor R2 and the fourth resistor R4 can also be connected to the second switch S2 respectively.

[0060] One end of the first resistor R1 and the third resistor R3 connected in parallel is connected to one end of the second resistor R2 and the fourth resistor R4 connected in parallel.

[0061] Wherein, the first capacitor and the positive electrode insulation resistance One end connected in parallel with the second capacitor Insulation resistance of negative electrode The connection point of the parallel connection is grounded to GND; the connection point of the first resistor R1 and the third resistor R3 in parallel with the connection point of the second resistor R2 and the fourth resistor R4 in parallel is grounded to GND.

[0062] Figure 1 In and They represent insulation resistance respectively. and Voltage at both ends; and This refers to the switches on the upper and lower measurement branches. The switches may include, but are not limited to, MOSFETs. Both switches may be closed or open simultaneously. and This indicates a known resistance in the measurement circuit.

[0063] Insulation testing is an important aspect of high-voltage safety for electric vehicles. The purpose of insulation testing is to calculate the insulation resistance value. When the insulation resistance value is less than a certain threshold, battery short circuits or leakage may occur, thereby threatening personnel safety.

[0064] The insulation detection circuit described in the above embodiments of the present invention specifically implements the insulation detection process as follows: Figure 2 As shown, the method applied to the insulation detection circuit illustrated above includes:

[0065] Step S201: Collect the first insulation resistance when both the first switch S1 and the second switch S2 are open based on the acquisition time. Second insulation resistance The first voltage point, and the first insulation resistance when both the first switch S1 and the second switch S2 are closed. Second insulation resistance The second voltage point.

[0066] The number of voltage points is preset according to the actual situation, and the first insulation resistance... The number of voltage points is M, and the second insulation resistance The number of voltage points is N, where M and N are both positive integers, and the number indicated by M and N may be different.

[0067] Among them, the first insulation resistance is the positive insulation resistance. That is, the first insulation resistance The second insulation resistance is the negative insulation resistance. That is, the second insulation resistance .

[0068] M represents the number of voltage points collected at a certain sampling time interval when the switch is open. Similarly, N represents the number of voltage points collected at a certain sampling time interval when the switch is closed.

[0069] In the specific implementation step S201, the first insulation resistance is collected at each sampling time when both the first switch S1 and the second switch S2 are open, according to the sampling time. The first voltage point will also be used to collect the second insulation resistance. The first voltage point.

[0070] Here, the number of sampling times is M, where M is a positive integer greater than or equal to 2.

[0071] Next, according to the sampling time, when the first switch S1 and the second switch S2 are closed simultaneously, the first insulation resistance is collected at each sampling moment. The second voltage point will also collect the second insulation resistance. The second voltage point, that is, the first insulation resistance when disconnected. The voltage of the last acquisition is used as the closing time. The initial value is the first voltage value at the second voltage point.

[0072] It should be noted that, generally speaking, the second voltage point when the first switch S1 and the second switch S2 are closed is collected after the first voltage point when the first switch S1 and the second switch S2 are open is collected.

[0073] Step S202: When both the first switch S1 and the second switch S2 are in the open state, based on the sampling time T and the corresponding voltage value of each first voltage point, the first capacitor... Second capacitor First insulation resistance Second insulation resistance and battery pack voltage Process the data to determine the corresponding first target parameter.

[0074] It should be noted that the specific implementation of step S202 includes the following steps.

[0075] Step S11: When both the first switch S1 and the second switch S2 are in the open state, the current in the insulation detection circuit flows through the first capacitor. Second capacitor First insulation resistance Second insulation resistance and battery pack voltage ;

[0076] In the specific implementation of step S11, when both the first switch S1 and the second switch S2 are in the open state, the other resistors on the right side of the insulation detection circuit are in the open state. At this time, the current in the insulation detection circuit only flows through the first capacitor. Second capacitor First insulation resistance Second insulation resistance and battery pack voltage At this point, insulation testing only needs to consider the devices through which current flows.

[0077] Step S12: Based on the first capacitor Second capacitor First insulation resistance Second insulation resistance and battery pack voltage Determine the first relationship between capacitance, resistance, and voltage at time k, where k is the current sampling time;

[0078] In the specific implementation of step S12, firstly, the first positive insulation resistance, i.e., the first insulation resistance, is collected when the first switch S1 and the second switch S2 are open. voltage across the two ends and take it as The initial value of is denoted as ; and record the insulation resistance of the negative electrode, i.e., the second insulation resistance. Voltage at both ends and the first voltage The initial value of is denoted as .

[0079] Next, according to Kirchhoff's current law, the relationship between capacitance, resistance and voltage in the insulation detection circuit can be obtained, as shown in formulas (1) and (2).

[0080] Formula (1):

[0081]

[0082] Formula (2):

[0083]

[0084] in, This is the positive insulation resistance, i.e., the first insulation resistance. voltage, For the first capacitor, For the second capacitor, This refers to the battery pack voltage. This is the negative insulation resistance, i.e., the second insulation resistance. The voltage.

[0085] Next, a Laplace transform is performed on equation (1) to obtain its expression in the s-domain, as shown in equation (3). Then, a Laplace transform is performed on equation (2) to obtain its expression in the s-domain. The expression for the domain is shown in formula (4).

[0086] Formula (3):

[0087]

[0088] Formula (4):

[0089]

[0090] in, For voltage initial value, For voltage initial value, It is the positive insulation resistance. The insulation resistance is the negative electrode. For the first capacitor, For the second capacitor, This refers to the battery pack voltage. For voltage The value in the S domain;

[0091] Then, substituting formula (4) into formula (3), we can obtain the battery pack voltage. and The relation in the s domain is shown in formula (5).

[0092] Formula (5):

[0093]

[0094] Next, formula (5) is rearranged to obtain its... The expression for is represented by formula (6).

[0095] Formula (6):

[0096]

[0097] Then, using The relationship between the s-domain and the s-domain is shown in Equation (7); by substituting Equation (7) into Equation (6) using the bilinear transformation method, the s-domain can be transformed. and The expression is converted to domain, obtain domain The expression is shown in formula (8).

[0098] Formula (7):

[0099]

[0100] Formula (8):

[0101]

[0102] Where T represents the sampling time, and the first parameter The second parameter The third parameter The fourth parameter .

[0103] Based on this, formula (8) is rearranged to obtain the voltage at time k. The expression for is the first relation, as shown in formula (9).

[0104] Formula (9):

[0105] in, and They represent Time and Voltage at any moment The value of the resistance. ,capacitance and battery pack voltage The values ​​of all are known constants, so the first, second, third and fourth parameters in formula (8) are all constants.

[0106] Step S13: Process the first relational expression according to the sampling time T and the corresponding voltage value of each first voltage point to obtain the first target parameter.

[0107] It should be noted that the specific implementation process of step S13 includes the following steps:

[0108] Step S21: For each first voltage point, if the first voltage point is the mth sampling, obtain the current sampling time and voltage value, as well as the voltage values ​​of the first voltage points in the previous m-1 samplings, where m is a positive integer greater than or equal to 2 and less than or equal to M.

[0109] In the specific implementation of step S21, for each first voltage point, if the first voltage point is the m-th sampling, it is necessary to obtain the current sampling time and voltage value, as well as the voltage values ​​of the first voltage points in the previous m-1...0 samplings. In other words, it is necessary to obtain the voltage value of the first voltage point in each previous sampling.

[0110] It should be noted that the first voltage point refers to the first insulation resistance. Voltage points at both ends.

[0111] Optionally, if the first voltage point is the first time it is acquired, no processing is performed.

[0112] Step S22: Substitute the current sampling time k and voltage value, as well as the voltage value of the first voltage point in the previous m-1 times, into the first relational expression to obtain the first relational expression corresponding to each first voltage point. The sampling time k belongs to the sampling time T.

[0113] In the specific implementation of step S22, for the first voltage point that is not the first time it is sampled, its current sampling time k and voltage value, as well as the voltage value of each previous first voltage point, are substituted into the first relational expression to obtain the first relational expression corresponding to each first voltage point. That is, a set of equations is obtained, as shown in formula (10) below.

[0114] Formula (10):

[0115]

[0116] Step S23: Identify the first relational expression corresponding to each first voltage point and determine the first target parameter, which is represented by insulation resistance, voltage and capacitance.

[0117] It should be noted that there may be cases where there is no solution when solving a system of equations. In such cases, the least squares approach can be used to solve the system and calculate the values ​​of the unknown parameters in the equations.

[0118] Parameter identification methods can be employed offline or online. For example, offline identification uses the least squares method, while online identification uses recursive least squares and recursive least squares with a forgetting factor to identify the values ​​of unknown parameters.

[0119] In one specific implementation, the first relational expression corresponding to each first voltage point in formula (10) is rearranged into a linear equation. Format. Among them, input data , , , ;in, The voltage values ​​at the first voltage point obtained in step S201 (k-1 times) are... This is the voltage value collected in the current sample.

[0120] Based on this, input The parameters can be obtained by calculating using the least squares method. and and parameters and The first target parameters are obtained by combining them.

[0121] In another embodiment, the first relational expression corresponding to each first voltage point in formula (10) is: In the form of. Among them, For each voltage value collected ; Indicates state, ; This indicates the parameters that need to be identified. Then, recursive least squares or recursive least squares with a forgetting factor is used to iteratively calculate the parameters. Finally, the parameters are... As the first target parameter.

[0122] In another embodiment, the first relational expression corresponding to each first voltage point in formula (10) is rearranged, and the state vector and observation equation are defined as follows: State vector The state equation of the system is ; Observation equation ,in Then, given the initial error covariance matrix, process noise covariance matrix, and measurement noise covariance matrix, the Kalman filter method is used to identify the vectors. Finally, the vector As the first target parameter.

[0123] It should be noted that, based on the process described in step S23, the first target parameter is represented by insulation resistance, voltage, and capacitance, that is, by... , , It consists of unknown parameters.

[0124] Step S203: When both the first switch S1 and the second switch S2 are closed, based on the sampling time T and the corresponding voltage value of each second voltage point, the first capacitor... Second capacitor First insulation resistance Second insulation resistance Other resistors, and battery pack voltage Process the data to determine the corresponding second target parameter;

[0125] It should be noted that the specific implementation of step S203 includes the following steps:

[0126] Step S31: When both the first switch S1 and the second switch S2 are closed, and the link between the first switch S1 and the first resistor R1 among the other resistors is closed, and the link between the second switch S2 and the second resistor R2 among the other resistors is closed, the current in the insulation detection circuit flows through the first capacitor. Second capacitor First insulation resistance Second insulation resistance The other resistors include the first resistor R1 and the second resistor R2, as well as the battery pack voltage. ;

[0127] In the specific implementation of step S31, when both the first switch S1 and the second switch S2 are in the closed state, it is determined that the link between the first switch S1 and the first resistor R1 in the upper branch is closed, and the link between the second switch S2 and the second resistor R2 in the lower branch is closed.

[0128] The upper branch includes the first resistor R1 and the third resistor R3, and the lower branch includes the second resistor R2 and the fourth resistor R4; the first resistor R1, the third resistor R3, the second resistor R2 and the fourth resistor R4 belong to other resistors.

[0129] At this time, the current in the insulation detection circuit flows through the first capacitor. Second capacitor First insulation resistance Second insulation resistance The other resistors include the first resistor R1 and the second resistor R2, as well as the battery pack voltage. ;

[0130] Optionally, the link between the first switch S1 and either the first resistor R1 or the third resistor R3 among the other resistors is closed, and the link between the second switch S2 and either the second resistor R2 or the fourth resistor R4 among the other resistors is closed. The current in the insulation detection circuit flows through the first capacitor. Second capacitor First insulation resistance Second insulation resistance Among the other resistors, the first resistor R1 or the third resistor R3, the second resistor R2 or the fourth resistor R4, and the battery pack voltage. ;

[0131] Step S32: Based on the first capacitor Second capacitor First insulation resistance Second insulation resistance The first resistor R1, the second resistor R2, and the battery pack voltage Determine the second relationship between capacitance, resistance, and voltage at time k, where k is the sampling time;

[0132] In the specific implementation of step S32, firstly, the first insulation resistance is collected when the first switch S1 and the second switch S2 are simultaneously closed and then opened. The steady-state voltage is used as the initial voltage value when the circuit is closed, i.e. It can also be written as When disconnected, the second insulation resistance The steady-state voltage is used as the initial voltage value when the circuit is closed. .

[0133] Among them, switch and When closed, the upper and lower resistance values ​​of the measuring circuit can be combined in different ways. (Using a switch...) and When closed, they are connected to respectively and For example, according to Kirchhoff's current law, the relationship between capacitance, resistance and voltage in the insulation detection circuit can be obtained, as shown in formula (11).

[0134] +

[0135] Next, by performing a Laplace transform on equation (11), the closed switch can be obtained. and hour, and exist The relation of the domain is shown in formula (12).

[0136] Formula (12):

[0137]

[0138] in, and These represent switches. and Voltage when closed simultaneously and The initial value of .

[0139] Rearranging formula (12), we still use... As input, As the output, the first insulation resistance is obtained. The voltage in the S-domain The expression is shown in formula (13).

[0140] Formula (13):

[0141]

[0142] Then, switch and The formula (13) expression when closed is performed The transformation involves substituting the bilinear equation (7) into equation (13) to obtain the voltage when the switch is closed. The expression in the z-domain is shown in formula (14). To simplify the formula, the parameters were substituted. Rearranging formula (14) yields the switch... and When closed, time The expression is shown in formula (15).

[0143] Formula (14):

[0144]

[0145] Formula (15):

[0146]

[0147] Among them, the third parameter The first parameter The fourth parameter The second parameter .

[0148] Based on this, the unknown parameters in formulas (9) and (15) can be determined. This is because capacitance, resistance, and sampling time... The values ​​of all are constants, so the unknown parameters in formulas (9) and (15) are all constants. , , , and All of them are constants. Therefore, the first, second, third and fourth parameters in formula (14) are all constants.

[0149] Here, the first parameter B, the second parameter Q, the third parameter A, and the fourth parameter P are parameters of the second objective parameter, while the first parameter... Second parameter Third parameter and the fourth parameter The parameters are the first target parameters.

[0150] Step S33: Process the second relationship according to the sampling time T and the corresponding voltage value of each second voltage point to obtain the second target parameter.

[0151] It should be noted that the specific implementation of step S33 includes the following steps.

[0152] Step S41: For each second voltage point, if the second voltage point is the nth sampling, obtain the current sampling time and voltage value, as well as the voltage value of the first voltage point in the previous n-1 samplings, where n is a positive integer greater than or equal to 2 and less than or equal to N.

[0153] The voltage value of the second voltage point acquired in the first sampling is the first insulation resistance when the first switch S1 and the second switch S2 are open. The voltage value, that is, the voltage value of the first voltage point corresponding to the Mth time. ;

[0154] Step S42: Substitute the current sampling time k and voltage value, as well as the voltage value of the first voltage point of the previous n-1 times, into the second relational expression to obtain the second relational expression corresponding to each second voltage point, wherein the sampling time k belongs to the sampling time T;

[0155] In the specific implementation of step S42, for the second voltage point that is not the first sampling, its current sampling time k and voltage value, as well as the voltage value of each previous second voltage point, are substituted into the second relational expression, i.e., formula (15), to obtain the second relational expression corresponding to each second voltage point. In other words, a set of equations is obtained, as shown in formula (16) below.

[0156] Formula (16):

[0157]

[0158] Step S43: Identify the second relational expression corresponding to each second voltage point and determine the second target parameter.

[0159] It should be noted that the specific implementation process of step S43 is the same as that of step S23 described above, and they can be referred to each other.

[0160] It should be noted that, based on the process described in step S23, the first target parameter is represented by insulation resistance, voltage, and capacitance; that is, by... , and It consists of unknown parameters.

[0161] Step S204: Determine the first insulation resistance based on the first target parameter and the second target parameter. Second insulation resistance The resistance value.

[0162] It should be noted that the specific implementation of step S204 includes the following steps:

[0163] Step S51: Calculate the first insulation resistance based on the first parameter in the first target parameters and the first parameter in the second target parameters. The resistance value;

[0164] In the specific implementation step S51, firstly, based on the first target parameter... , , First calculate The value; and then based on the second target parameter , and Calculate The value, according to or The value of the resistance is calculated. The value of .

[0165] Step S52: Calculate the second insulation resistance based on the second parameter in the first target parameters and the second parameter in the second target parameters. The resistance value.

[0166] In the specific implementation step S52, firstly, based on the first target parameter... , , First calculate The value; and then based on the second target parameter , and Calculate The value, according to or The value of the resistance is calculated. The value of .

[0167] The value of Q varies depending on the branch connected to the first switch S1 and the second switch S2. For example, if the link between the first switch S1 and the first resistor R1 among the other resistors is closed, and the link between the second switch S2 and the fourth resistor R4 among the other resistors is closed... .

[0168] Optionally, based on the method shown in steps S201 to S204 above, it can also be illustrated by a flowchart, such as... Figure 3 As shown.

[0169] In this embodiment of the invention, the switch is obtained according to Kirchhoff's current law. and The equations for the current in the circuit when it is open and closed, after Laplace transform and... Voltage obtained by transformation The expression at time k is used to calculate the switch. and The unknown parameter in the expression corresponding to the opening and closing states allows for the calculation of the insulation resistance value. This avoids other factors affecting the accuracy of the measurement results and prevents interference signals, enabling the detection of potential insulation faults in a shorter time, which is of great significance for ensuring the safety of personnel and vehicles.

[0170] Based on the insulation testing method shown in the above embodiments of the present invention, correspondingly, the present invention also discloses a flowchart of another insulation testing method, as follows: Figure 4 As shown, the method includes:

[0171] Step S401: Collect the first insulation resistance when both the first switch S1 and the second switch S2 are open based on the acquisition time. The first voltage point, and the first insulation resistance when both the first switch S1 and the second switch S2 are closed. The second voltage point.

[0172] Step S402: When both the first switch S1 and the second switch S2 are in the open state, based on the sampling time T and the corresponding voltage value of each first voltage point, the first capacitor... Second capacitor First insulation resistance Second insulation resistance and battery pack voltage Process the data to determine the corresponding first target parameter.

[0173] Step S403: When both the first switch S1 and the second switch S2 are closed, based on the sampling time T and the corresponding voltage value of each second voltage point, the first capacitor... Second capacitor First insulation resistance Second insulation resistance Other resistors, and battery pack voltage Process the data to determine the corresponding second target parameter.

[0174] Step S404: Determine the first insulation resistance based on the first target parameter and the second target parameter. Second insulation resistance The resistance value.

[0175] It should be noted that the implementation process of steps S401 to S404 is the same as that of steps S201 to S204 in the above embodiment, and they can be referred to each other.

[0176] Step S405: Determine the first insulation resistance Whether the resistance value is less than the first threshold, and the second insulation resistance If the resistance value is less than the second threshold, then proceed to step S406. If either is true or both are false, it indicates that the insulation detection circuit does not have an insulation fault.

[0177] In the specific implementation step S405, the first insulation resistance is compared. The resistance value and the first threshold, the second insulation resistance The resistance value and the magnitude of the second threshold, if the first insulation resistance The resistance is less than the first threshold, and the second insulation resistance If the resistance value is less than the second threshold, step S406 is executed; otherwise, it indicates that the insulation detection circuit does not have an insulation fault.

[0178] It should be noted that both the first threshold and the second threshold are set in advance by technicians based on the actual situation. The first threshold and the second threshold may be equal or unequal.

[0179] Step S406: Determine that there is an insulation fault in the insulation detection circuit.

[0180] In the specific implementation of step S406, it is determined that there is an insulation fault in the insulation detection circuit. That is to say, there may be a short circuit or leakage in the insulation circuit, which threatens personnel safety.

[0181] In this embodiment of the invention, the switch is obtained according to Kirchhoff's current law. and The equations for the current in the circuit when it is open and closed, after Laplace transform and... Voltage obtained by transformation The expression at time k is used to calculate the switch. and The unknown parameter in the expression corresponding to the opening and closing states allows for the calculation of the insulation resistance value. This avoids other methods from affecting the accuracy of the measurement results and prevents other interference signals. When the insulation resistance value is less than a certain threshold, battery short circuits or leakage may occur, threatening personnel safety. The above method can detect potential insulation faults in a short time, ensuring the safety of personnel and vehicles.

[0182] Based on the insulation detection method shown in the above embodiments of the present invention, correspondingly, the present invention also discloses a schematic diagram of an insulation detection device applied to an insulation detection circuit. The insulation detection circuit includes a first switch S1, a second switch S2, and a first insulation resistor. Second insulation resistance First capacitor Second capacitor Battery pack voltage and other resistors, such as Figure 5 As shown, the device includes:

[0183] Acquisition unit 501 is used to acquire the first insulation resistance when both the first switch S1 and the second switch S2 are open, based on the acquisition time. Second insulation resistance The first voltage point, and the first insulation resistance when both the first switch S1 and the second switch S2 are closed. Second insulation resistance The second voltage point;

[0184] The first processing unit 502 is configured to, when both the first switch S1 and the second switch S2 are in the open state, based on the sampling time T and the corresponding voltage value of each first voltage point, configure the first capacitor... Second capacitor First insulation resistance Second insulation resistance and battery pack voltage Perform circuit processing to determine the corresponding first target parameter;

[0185] The second processing unit 503 is configured to, when both the first switch S1 and the second switch S2 are closed, based on the sampling time T and the corresponding voltage value of each second voltage point, configure the first capacitor... Second capacitor First insulation resistance Second insulation resistance Other resistors, and battery pack voltage Process the data to determine the corresponding second target parameter;

[0186] Determining unit 504 is used to determine the first insulation resistance based on the first target parameter and the second target parameter. Second insulation resistance The resistance value.

[0187] The specific principles and execution processes of each unit in the insulation testing device disclosed in the above embodiments of the present invention are the same as the corresponding contents in the insulation testing method provided in the above embodiments of the present invention. Please refer to the corresponding parts in the insulation testing method disclosed in the above embodiments of the present invention, and they will not be repeated here.

[0188] In this embodiment of the invention, the switch is obtained according to Kirchhoff's current law. and The equations for the current in the circuit when it is open and closed, after Laplace transform and... Voltage obtained by transformation The expression at time k is used to calculate the switch. and The unknown parameter in the expression corresponding to the opening and closing states allows for the calculation of the insulation resistance value. This avoids other factors affecting the accuracy of the measurement results and prevents interference signals, enabling the detection of potential insulation faults in a shorter time, which is of great significance for ensuring the safety of personnel and vehicles.

[0189] Optionally, based on the insulation detection device shown in the above embodiments of the present invention, the first processing unit 502 is specifically used for:

[0190] When both the first switch S1 and the second switch S2 are in the open state, the current in the insulation detection circuit flows through the first capacitor. Second capacitor First insulation resistance Second insulation resistance and battery pack voltage ;

[0191] Based on the first capacitor Second capacitor First insulation resistance Second insulation resistance and battery pack voltage Determine the first relationship between capacitance, resistance, and voltage at time k, where k is the current sampling time;

[0192] The first relational expression is processed based on the sampling time T and the corresponding voltage value for each first voltage point to obtain the first target parameter.

[0193] The first target parameter is obtained by processing the first relational expression based on the sampling time T and the corresponding voltage value of each first voltage point, including:

[0194] For each first voltage point, if the first voltage point is the mth sampling, obtain the current sampling time and voltage value, as well as the voltage values ​​of the first voltage points in the previous m-1 samplings, where m is a positive integer greater than or equal to 2 and less than or equal to M.

[0195] Substituting the current sampling time k and voltage value, as well as the voltage value of the first voltage point in the previous m-1 times, into the first relational expression, we obtain the first relational expression corresponding to each first voltage point. The sampling time k belongs to the sampling time T.

[0196] The first relational expression corresponding to each first voltage point is identified to determine the first target parameter.

[0197] Optionally, based on the insulation detection device shown in the above embodiments of the present invention, the second processing unit 503 is specifically used for:

[0198] When both the first switch S1 and the second switch S2 are closed, and the link between the first switch and the first resistor among the other resistors is closed, and the link between the second switch and the second resistor among the other resistors is closed, the current in the insulation detection circuit flows through the first capacitor. Second capacitor First insulation resistance Second insulation resistance The other resistors include the first resistor R1 and the second resistor R2, as well as the battery pack voltage. ;

[0199] Based on the first capacitor Second capacitor First insulation resistance Second insulation resistance The first resistor, the second resistor, and the battery pack voltage Determine the second relationship between capacitance, resistance, and voltage at time k, where k is the sampling time;

[0200] The second relation is processed based on the sampling time T and the corresponding voltage value of each second voltage point to obtain the second target parameter.

[0201] Specifically, the second relational expression is processed based on the sampling time T and the corresponding voltage value of each second voltage point to obtain the second target parameters, including:

[0202] For each second voltage point, if the second voltage point is the nth sampling, obtain the current sampling time and voltage value, as well as the voltage value of the first voltage point in the previous n-1 samplings, where n is a positive integer greater than or equal to 2 and less than or equal to N;

[0203] Substituting the current sampling time k and voltage value, as well as the voltage value of the first voltage point in the previous n-1 times, into the second relational expression, we obtain the second relational expression corresponding to each second voltage point. The sampling time k belongs to the sampling time T.

[0204] The second relational expression corresponding to each second voltage point is identified to determine the second target parameter.

[0205] Optionally, based on the insulation detection device shown in the above embodiments of the present invention, the determining unit 504 is specifically used for:

[0206] The first insulation resistance is calculated based on the first parameter in the first target parameters and the first parameter in the second target parameters. The resistance value;

[0207] The second insulation resistance is calculated based on the second parameter in the first target parameter and the second parameter in the second target parameter. The resistance value.

[0208] Optionally, based on the insulation detection device shown in the above embodiments of the present invention, the determining unit 504 is further configured to:

[0209] Determine the first insulation resistance Whether the resistance value is less than the first threshold, and the second insulation resistance Is the resistance value less than the second threshold?

[0210] If both are true, it is determined that the insulation detection circuit has an insulation fault.

[0211] This application provides an electronic device, which includes a processor and a memory. The memory is used to store insulation detection program code and data, and the processor is used to call the program instructions in the memory to execute the steps shown in the insulation detection method in the above embodiments.

[0212] This invention provides a storage medium, which includes the electronic device provided in the above-described embodiments of this application. The electronic device is used to execute the insulation detection method disclosed in the embodiments of this application.

[0213] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the descriptions in the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0214] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0215] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An insulation testing method, characterized in that, An insulation detection circuit is applied to an insulation detection circuit, the insulation detection circuit including a first switch, a second switch, a first insulation resistor, a second insulation resistor, a first capacitor, a second capacitor, a battery pack voltage, and other resistors, the method including: The data is collected based on the acquisition time, specifically the first voltage point of the first insulation resistance and the second insulation resistance when both the first switch and the second switch are open, and the second voltage point of the first insulation resistance and the second insulation resistance when both the first switch and the second switch are closed. When both the first switch and the second switch are in the off state, the first target parameter is determined by processing based on the sampling time and corresponding voltage value of each first voltage point, the first capacitor, the second capacitor, the first insulation resistance, the second insulation resistance, and the battery pack voltage. When both the first switch and the second switch are in the closed state, the sampling time T and the corresponding voltage value of each second voltage point, the first capacitor, the second capacitor, the first insulation resistance, the second insulation resistance, other resistances, and the battery pack voltage are processed to determine the corresponding second target parameter. The resistance values ​​of the first insulation resistance and the second insulation resistance are determined based on the first target parameter and the second target parameter.

2. The method according to claim 1, characterized in that, When both the first switch and the second switch are in the open state, the first target parameter is determined based on the sampling time and corresponding voltage value of each first voltage point, the first capacitor, the second capacitor, the first insulation resistance, the second insulation resistance, and the battery pack voltage, including: When both the first switch and the second switch are in the open state, the current in the insulation detection circuit flows through the first capacitor, the second capacitor, the first insulation resistance, the second insulation resistance, and the battery pack voltage. Based on the first capacitor, the second capacitor, the first insulation resistance, the second insulation resistance, and the battery pack voltage, a first relationship between the capacitor, resistance, and voltage at time k is determined, where k is the current sampling time. The first relational expression is processed based on the sampling time and corresponding voltage value of each first voltage point to obtain the first target parameter.

3. The method according to claim 2, characterized in that, The first relational expression is processed based on the sampling time and corresponding voltage value of each first voltage point to obtain the first target parameter, including: For each first voltage point, if the first voltage point is the mth sampling, obtain the current sampling time and voltage value, as well as the voltage values ​​of the first voltage points in the previous m-1 samplings, where m is a positive integer greater than or equal to 2 and less than or equal to M. Substituting the current sampling time k and voltage value, as well as the voltage value of the first voltage point in the previous m-1 times, into the first relational expression, we obtain the first relational expression corresponding to each first voltage point. The sampling time k belongs to the sampling time. The first relational expression corresponding to each first voltage point is identified to determine the first target parameter.

4. The method according to claim 1, characterized in that, When both the first switch and the second switch are closed, the sampling time and corresponding voltage value of each second voltage point, the first capacitor, the second capacitor, the first insulation resistance, the second insulation resistance, other resistances, and the battery pack voltage are processed to determine the corresponding second target parameters, including: When both the first switch and the second switch are closed, and the link between the first switch and the first resistor among the other resistors is closed, and the link between the second switch and the second resistor among the other resistors is closed, the current in the insulation detection circuit flows through the first capacitor, the second capacitor, the first insulation resistor, the second insulation resistor, the first and second resistors among the other resistors, and the battery pack voltage; Based on the first capacitor, the second capacitor, the first insulation resistance, the second insulation resistance, the first resistance, the second resistance, and the battery pack voltage, a second relationship between the capacitor, resistance, and voltage at time k is determined, where k is the sampling time. The second relation is processed based on the sampling time T and the corresponding voltage value of each second voltage point to obtain the second target parameter.

5. The method according to claim 4, characterized in that, The second relationship is processed based on the sampling time T and the corresponding voltage value of each second voltage point to obtain the second target parameters, including: For each second voltage point, if the second voltage point is the nth sampling, obtain the sampling time and voltage value of the current sampling, as well as the voltage value of the first voltage point of the previous n-1 samplings, where n is a positive integer greater than or equal to 2 and less than or equal to N; Substituting the current sampling time k and voltage value, as well as the voltage value of the first voltage point in the previous n-1 times, into the second relational expression, we obtain the second relational expression corresponding to each second voltage point. The sampling time k belongs to the sampling time. The second relational expression corresponding to each second voltage point is identified to determine the second target parameter.

6. The method according to claim 1, characterized in that, Determining the resistance values ​​of the first insulation resistance and the second insulation resistance based on the first target parameter and the second target parameter includes: The resistance value of the first insulation resistance is calculated based on the first parameter in the first target parameters and the first parameter in the second target parameters; The resistance value of the second insulation resistance is calculated based on the second parameter in the first target parameter and the second parameter in the second target parameter.

7. The method according to claim 1, characterized in that, Also includes: Determine whether the resistance value of the first insulation resistor is less than a first threshold and whether the resistance value of the second insulation resistor is less than a second threshold; If both are true, it is determined that the insulation detection circuit has an insulation fault.

8. An insulation testing device, characterized in that, An insulation detection circuit is used, comprising a first switch, a second switch, a first insulation resistor, a second insulation resistor, a first capacitor, a second capacitor, a battery pack voltage, and other resistors. The device includes: The acquisition unit is used to acquire, based on the acquisition time, the first voltage point of the first insulation resistance and the second insulation resistance when both the first switch and the second switch are open, and the second voltage point of the first insulation resistance and the second insulation resistance when both the first switch and the second switch are closed; The first processing unit is configured to perform circuit processing based on the sampling time and corresponding voltage value of each first voltage point, the first capacitor, the second capacitor, the first insulation resistance, the second insulation resistance, and the battery pack voltage when both the first switch and the second switch are in the off state, and to determine the corresponding first target parameter. The second processing unit is used to determine the corresponding second target parameter based on the sampling time and corresponding voltage value of each second voltage point, the first capacitor, the second capacitor, the first insulation resistance, the second insulation resistance, other resistances, and the battery pack voltage when both the first switch and the second switch are in the closed state. The determining unit is used to determine the resistance values ​​of the first insulation resistance and the second insulation resistance based on the first target parameter and the second target parameter.

9. An electronic device, characterized in that, The electronic device includes a processor and a memory, the memory being used to store program code and data for data generation, and the processor being used to call program instructions in the memory to execute the insulation detection method as described in any one of claims 1-7.

10. A storage medium, characterized in that, The storage medium includes a stored program, wherein, when the program is executed, it controls the device containing the storage medium to perform the data insulation detection method as described in any one of claims 1-7.

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