Insulation resistance determination method and device, and computer-readable storage medium

Abstract

The present invention discloses a method for determining insulation resistance, an apparatus thereof, and a computer-readable storage medium. The method comprises: responding to an insulation detection request and obtaining a first voltage of a main relay; obtaining a second voltage when it is determined that the voltage difference between the first voltage and a historical voltage satisfies a first preset condition; triggering the closure of a secondary relay after obtaining the second voltage, and obtaining a third voltage when the voltage difference between the second voltage and a second voltage threshold satisfies a second preset condition, wherein the third voltage is the voltage value obtained when the second voltage meets the third voltage threshold; and determining the insulation resistance based on the second and third voltages. The present invention solves the technical problem that the means for collecting insulation resistance values ​​in related technologies do not adequately consider environmental factors, resulting in inaccurate detection results.

Description

Technical Field

[0001] The present invention relates to the field of electronic devices, and in particular to a method for determining insulation resistance, a device thereof, and a computer-readable storage medium. Background Art

[0002] Currently, there are two methods for measuring the insulation resistance of electric vehicles in my country: one is signal injection, and the other is external resistor switching. The existing external resistor switching insulation resistance measurement method has low detection accuracy. Furthermore, the long-term connection of the measurement resistor reduces the system's insulation performance and increases battery power consumption.

[0003] There are two ways to obtain the insulation detection voltage in the existing control strategy: 1) Use the same insulation detection cycle regardless of the upper and lower high-voltage states of the battery; 2) Identify the upper and lower high-voltage states of the battery and achieve different insulation detection cycles by calibrating different times. For example, when the high voltage is not applied, the waiting time after closing the insulation detection relay is short (calibrable), and when the high voltage is applied, the waiting time after closing the insulation detection relay is long (calibrable). The first method: The insulation detection cycle is long, and it cannot guarantee that the battery can quickly diagnose the insulation resistance fault before the high voltage is applied, which affects the speed of power-on initialization. The second method: Although it can guarantee the different insulation detection cycle requirements under the upper and lower high-voltage states of the battery, it is not adaptable to the different external and vehicle environments.

[0004] To address the above-mentioned problems, no effective solutions have been proposed so far. Summary of the Invention

[0005] The embodiments of the present invention provide a method for determining insulation resistance, an apparatus thereof, and a computer-readable storage medium, to at least solve the technical problem that the means for collecting insulation resistance values ​​in related technologies do not adequately consider environmental factors, resulting in inaccurate detection results.

[0006] According to one aspect of an embodiment of the present invention, a method for determining insulation resistance is provided, including: responding to an insulation detection request, and obtaining a first voltage of a main relay, wherein the first voltage is a dynamic voltage value after closing the main relay; when it is determined that the voltage difference between the first voltage and the historical voltage meets a first preset condition, obtaining a second voltage, wherein the second voltage is a voltage value obtained when the first voltage reaches a first voltage threshold, and the historical voltage is an average voltage value in the previous statistical period; after obtaining the second voltage, triggering the auxiliary relay to close, and when the voltage difference between the second voltage and the second voltage threshold meets a second preset condition, obtaining a third voltage, wherein the third voltage is a voltage value obtained when the second voltage meets the third voltage threshold; and determining the insulation resistance based on the second voltage and the third voltage.

[0007] Optionally, before responding to the insulation detection request and obtaining the first voltage of the main relay, the method also includes: obtaining the voltage ratio of the positive terminal voltage to the negative terminal voltage of the main relay; obtaining the comparison result of the voltage ratio and the fourth voltage threshold; when the comparison result is that the voltage ratio is greater than the fourth voltage threshold, prohibiting the main relay from performing upper high voltage and lower high voltage operations; when the comparison result is that the voltage ratio is not greater than the fourth voltage threshold, allowing the main relay to perform upper high voltage operation.

[0008] Optionally, when it is determined that the voltage difference between the first voltage and the historical voltage meets a first preset condition, a second voltage is obtained, including: obtaining a first change value between the first voltage and the historical voltage; comparing the first change value with a fifth voltage threshold, and when it is determined that the first change value is not greater than the fifth voltage threshold, obtaining a first duration, wherein the first duration is the duration that starts when it is determined that the first change value is not greater than the fifth voltage threshold; when the first duration is greater than the first duration threshold, or when the second duration is greater than the second duration threshold, obtaining the second voltage, wherein the second duration is the total duration of the main relay startup.

[0009] Optionally, after obtaining the second voltage, the auxiliary relay is triggered to close, and when the voltage difference between the second voltage and the second voltage threshold meets the second preset condition, the third voltage is obtained, including: obtaining the second change value of the second voltage, wherein the second change value is the absolute value of the difference between the dynamic voltage maximum and minimum values ​​of the second voltage; comparing the second change value with the sixth voltage threshold; when it is determined that the second change value is not greater than the sixth voltage threshold, obtaining a third duration, wherein the third duration is the duration that starts when it is determined that the second change value is not greater than the sixth voltage threshold; when the third time length is greater than the third time length threshold, or when the fourth time length is greater than the fourth time length threshold, obtaining the second voltage, wherein the fourth time length is the total duration of the auxiliary relay startup.

[0010] According to one aspect of an embodiment of the present invention, a device for determining insulation resistance is also provided, including: a first acquisition module, used to respond to an insulation detection request and obtain a first voltage of a main relay, wherein the first voltage is a dynamic voltage value after closing the main relay; a second acquisition module, used to obtain a second voltage when it is determined that the voltage difference between the first voltage and the historical voltage meets a first preset condition, wherein the second voltage is the voltage value obtained when the first voltage reaches a first voltage threshold, and the historical voltage is the average voltage value in the previous statistical period; a third acquisition module, used to trigger the closure of the auxiliary relay after obtaining the second voltage, and obtain a third voltage when the voltage difference between the second voltage and the second voltage threshold meets a second preset condition, wherein the third voltage is the voltage value obtained when the second voltage meets the third voltage threshold; a determination module, used to determine the insulation resistance of the insulation resistance based on the second voltage and the third voltage.

[0011] Optionally, the device also includes: a first acquisition unit, used to obtain the voltage ratio of the positive terminal voltage to the negative terminal voltage of the main relay in response to the insulation detection request and before obtaining the first voltage of the main relay; a second acquisition unit, used to obtain the comparison result of the voltage ratio and the fourth voltage threshold; a prohibition unit, used to prohibit the main relay from performing upper high voltage and lower high voltage operations when the comparison result is that the voltage ratio is greater than the fourth voltage threshold; and a permission unit, used to allow the main relay to perform upper high voltage operation when the comparison result is that the voltage ratio is not greater than the fourth voltage threshold.

[0012] Optionally, the second acquisition module includes: a third acquisition unit, used to obtain a first change value between the first voltage and the historical voltage; a fourth acquisition unit, used to compare the first change value with a fifth voltage threshold, and obtain a first duration when it is determined that the first change value is not greater than the fifth voltage threshold, wherein the first duration is the duration that starts when it is determined that the first change value is not greater than the fifth voltage threshold; a fifth acquisition unit, used to obtain the second voltage when the first duration is greater than the first duration threshold, or when the second duration is greater than the second duration threshold, wherein the second duration is the total duration of the main relay startup.

[0013] Optionally, the third acquisition module includes: a sixth acquisition unit, used to obtain a second change value of the second voltage, wherein the second change value is the absolute value of the difference between the dynamic voltage maximum and minimum values ​​of the second voltage; a comparison unit, used to compare the second change value with the sixth voltage threshold; a seventh acquisition unit, used to obtain a third duration when it is determined that the second change value is not greater than the sixth voltage threshold, wherein the third duration is the duration that starts when it is determined that the second change value is not greater than the sixth voltage threshold; an eighth acquisition unit, used to obtain the second voltage when the third duration is greater than the third duration threshold, or when the fourth duration is greater than the fourth duration threshold, wherein the fourth duration is the total duration of the auxiliary relay startup.

[0014] According to one aspect of an embodiment of the present invention, a computer-readable storage medium is further provided, wherein the computer-readable storage medium includes a stored program, wherein when the program is run, the device where the computer-readable storage medium is located is controlled to execute any one of the methods for determining insulation resistance.

[0015] According to one aspect of an embodiment of the present invention, a processor is further provided, wherein the processor is configured to run a program, wherein the program executes any one of the methods for determining insulation resistance when running.

[0016] In an embodiment of the present invention, in response to an insulation detection request, a first voltage of the main relay is obtained, wherein the first voltage is a dynamic voltage value after closing the main relay; when it is determined that the voltage difference between the first voltage and the historical voltage meets a first preset condition, a second voltage is obtained, wherein the second voltage is a voltage value obtained when the first voltage reaches a first voltage threshold, and the historical voltage is an average voltage value in the previous statistical period; after obtaining the second voltage, the auxiliary relay is triggered to close, and when the voltage difference between the second voltage and the second voltage threshold meets a second preset condition, a third voltage is obtained, wherein the third voltage is a voltage value obtained when the second voltage meets the third voltage threshold; and the insulation resistance is determined based on the second voltage and the third voltage. The insulation resistance determination method provided by the embodiment of the present invention achieves the purpose of measuring the insulation resistance value when the system relay voltage is stable, thereby achieving the technical effect of improving the accuracy of insulation resistance detection, and further solving the technical problem that the means for collecting insulation resistance values ​​in the related art do not fully consider environmental factors, resulting in inaccurate detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 is a flow chart of a method for determining insulation resistance according to an embodiment of the present invention;

[0019] Figure 2 An unbalanced bridge method insulation resistance measurement circuit according to an embodiment of the present invention;

[0020] Figure 3 is a flow chart of an unbalanced bridge method insulation detection process and control strategy according to an embodiment of the present invention;

[0021] Figure 4 FIG. 4 is a schematic diagram of a device for determining insulation resistance according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0023] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] Example 1

[0025] According to an embodiment of the present invention, a method embodiment of a method for determining insulation resistance is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0026] Figure 1 is a flow chart of a method for determining insulation resistance according to an embodiment of the present invention, such as Figure 1 As shown, the method includes the following steps:

[0027] Step S102, responding to the insulation detection request and acquiring a first voltage of the main relay, wherein the first voltage is a dynamic voltage value after the main relay is closed;

[0028] Optionally, in the above steps, an insulation detection request is first made after the low voltage electricity is initialized on the system, then the insulation detection main relay is closed and the timing is started, and then the dynamic insulation detection voltage (ie, the first voltage) in the current monitoring interval is detected.

[0029] It should be noted that the first voltage refers to the dynamic voltage value immediately after the main relay is closed.

[0030] Step S104: When it is determined that the voltage difference between the first voltage and the historical voltage meets the first preset condition, a second voltage is obtained, where the second voltage is a voltage value obtained when the first voltage reaches the first voltage threshold, and the historical voltage is an average voltage value in the previous statistical period;

[0031] Optionally, in the above steps, the difference between the first voltage and the historical voltage is compared with a preset threshold, and then further judgment is made based on the comparison result. When the preset conditions are met, the second voltage (ie, voltage values ​​Upos and Uneg) is obtained.

[0032] It should be noted that the historical voltage includes but is not limited to the average voltage in the last statistical period, and may also be the average voltage in the previous historical period.

[0033] Step S106, after obtaining the second voltage, triggering the secondary relay to close, and obtaining a third voltage when the voltage difference between the second voltage and the second voltage threshold meets a second preset condition, wherein the third voltage is the voltage value obtained when the second voltage meets the third voltage threshold;

[0034] In the above steps, after determining that the second voltage is obtained, the auxiliary relay (positive relay or negative relay) is closed, and the dynamic change value of the second voltage is monitored to see whether it meets the preset conditions. Then, when it is met, the insulation detection voltage value (i.e., the third voltage) is obtained.

[0035] Step S108 : determining the insulation resistance of the insulation resistor based on the second voltage and the third voltage.

[0036] Figure 2 The unbalanced bridge method insulation resistance measurement circuit according to an embodiment of the present invention is as follows. Figure 2As shown in the figure, using the unbalanced bridge method as an example, three relays must be driven. The collected insulation test voltage must stabilize before the calculated insulation resistance value is relatively accurate. Furthermore, the insulation test voltage takes different times to stabilize when the battery is not in high-voltage mode and when it is in high-voltage mode. Without high-voltage mode, the insulation test voltage is largely unaffected by the external environment and the vehicle's overall environment, requiring less time to stabilize. However, after high-voltage mode is applied, the insulation test voltage takes longer to stabilize due to the influence of the Y capacitor.

[0037] 1) Measure the resistance as follows:

[0038] —R1: Measure the resistance of the positive terminal of the device

[0039] —R2: Measure the resistance of the negative terminal of the device

[0040] —Ro_P: Standard known resistance for calculating insulation resistance of the main positive terminal

[0041] —Ro_N: Standard known resistance for calculating insulation resistance of the main negative terminal

[0042] —RIns_P: Calculated insulation resistance of the main positive terminal

[0043] —RIns_N: Calculated insulation resistance of the main negative terminal

[0044] 2) The relay is as follows:

[0045] —Switch Main: Main insulation detection relay

[0046] —Switch Pos: Positive terminal insulation detection relay

[0047] —Switch Neg: Negative terminal insulation detection relay

[0048] 3) The measurement parameters are as follows:

[0049] —Upos: positive terminal measurement voltage

[0050] —Uneg: Negative terminal measurement voltage

[0051] 4) The measurement steps are as follows:

[0052] The main insulation detection relay (Switch Main) is closed to obtain the positive terminal measurement voltage (Upos) and the negative terminal measurement voltage (Uneg); Upos and Uneg are judged. If Upos>Uneg, the positive terminal insulation detection relay (Switch Pos) is closed, R1 and Ro_P are connected to the circuit, and the positive terminal measurement voltage (UposwithR1) and the negative terminal measurement voltage (UnegwithR1) are re-obtained; otherwise, if Upos≤Uneg, the negative terminal insulation detection relay (Switch Neg) is closed, R2 and Ro_N are connected to the circuit, and the positive terminal measurement voltage (UposwithR2) and the negative terminal measurement voltage (UnegwithR2) are re-obtained; the main positive terminal insulation resistance RIns_P and the main negative terminal insulation resistance RIns_N are calculated according to the formula.

[0053] The calculation formula for the main positive terminal insulation resistance RIns_P is: If you choose to correct the calculated main positive terminal insulation resistance to reflect the actual insulation resistance, the correction formula is: The calculation formula of the main negative terminal insulation resistance RIns_N is: If you choose to correct the calculated main negative terminal insulation resistance to reflect the actual insulation resistance, the correction formula is:

[0054] As can be seen from the above, in an embodiment of the present invention, first, in response to an insulation detection request, a first voltage of the main relay can be obtained, wherein the first voltage is a dynamic voltage value after closing the main relay; then, when it is determined that the voltage difference between the first voltage and the historical voltage meets a first preset condition, a second voltage can be obtained, wherein the second voltage is the voltage value obtained when the first voltage reaches the first voltage threshold, and the historical voltage is the average voltage value in the last statistical period; then, after obtaining the second voltage, the auxiliary relay can be triggered to close, and when the voltage difference between the second voltage and the second voltage threshold meets a second preset condition, a third voltage can be obtained, wherein the third voltage is the voltage value obtained when the second voltage meets the third voltage threshold; finally, the insulation resistance of the insulation resistance can be determined based on the second voltage and the third voltage. The method for determining the insulation resistance provided by the embodiment of the present invention achieves the purpose of measuring the insulation resistance value when the system relay voltage is stable, thereby achieving the technical effect of improving the accuracy of insulation resistance detection, and thus solving the technical problem that the means for collecting insulation resistance values ​​in the related art do not fully consider environmental factors, resulting in inaccurate detection results.

[0055] As an optional embodiment, before responding to an insulation detection request and obtaining the first voltage of the main relay, the method also includes: obtaining the voltage ratio of the positive terminal voltage to the negative terminal voltage of the main relay; obtaining a comparison result of the voltage ratio with a fourth voltage threshold; when the comparison result is that the voltage ratio is greater than the fourth voltage threshold, prohibiting the main relay from performing upper high voltage and lower high voltage operations; when the comparison result is that the voltage ratio is not greater than the fourth voltage threshold, allowing the main relay to perform upper high voltage operation.

[0056] It should be noted that the purpose of determining the positive-negative voltage ratio is to promptly diagnose a leakage fault. If leakage occurs, high voltage is prohibited to ensure personal safety.

[0057] In the above optional embodiment, the insulation detection main relay is closed and the timing is started, and the ratio of the positive terminal voltage to the negative terminal voltage (including the positive terminal to the negative terminal ratio and the negative terminal to the positive terminal ratio) is calculated with a delay. It is determined whether these two ratios exceed a certain value. If they exceed the calibration value, the battery is prohibited from applying high voltage. Otherwise, high voltage is allowed. This control strategy can ensure that insulation detection faults are quickly diagnosed before applying high voltage, improving the power-on initialization speed. If the battery is already at high voltage and the fault is detected at this time, it is necessary to control the battery to reduce high voltage.

[0058] As an optional embodiment, when it is determined that the voltage difference between the first voltage and the historical voltage meets the first preset condition, the second voltage is obtained, including: obtaining a first change value between the first voltage and the historical voltage; comparing the first change value with the fifth voltage threshold, and when it is determined that the first change value is not greater than the fifth voltage threshold, obtaining a first duration, wherein the first duration is the duration that starts when it is determined that the first change value is not greater than the fifth voltage threshold; when the first duration is greater than the first duration threshold, or when the second duration is greater than the second duration threshold, obtaining the second voltage, wherein the second duration is the total duration of the main relay startup.

[0059] In the above optional embodiment, the change value between the first voltage and the average voltage value in the previous cycle (i.e., the historical voltage) is first obtained. When it is determined that the change value is less than a preset threshold or close to 0 (i.e., after it begins to stabilize), the timing is started and the timing time is counted. Then, it is determined that when the duration of the timing period (i.e., the first duration, i.e., the duration of voltage stability, it should be noted that the first duration can be multiple steps, equivalent to multiple debounces) is greater than the first duration threshold, or when the duration since the main relay is closed (i.e., the second duration) is greater than the second duration threshold, the insulation detection voltage value is obtained and calculated; in addition, if the duration of the timing period (i.e., the first duration) is not greater than the first duration threshold, or when the duration since the main relay is closed (i.e., the second duration) is not greater than the second duration threshold, the determination is re-evaluated. After the second voltage is obtained, the next step is performed to close the auxiliary relay.

[0060] It should be noted that, in practice, in order to prevent the voltage from being unstable, the second voltage can be obtained by judging according to the longest time after closing the main relay (for example, after 10 seconds, the time can be calibrated).

[0061] As an optional embodiment, after obtaining the second voltage, the auxiliary relay is triggered to close, and when the voltage difference between the second voltage and the second voltage threshold meets the second preset condition, the third voltage is obtained, including: obtaining the second change value of the second voltage, wherein the second change value is the absolute value of the difference between the dynamic voltage maximum and minimum values ​​of the second voltage; comparing the second change value with the sixth voltage threshold; when it is determined that the second change value is not greater than the sixth voltage threshold, obtaining the third time length, wherein the third time length is the time length starting when it is determined that the second change value is not greater than the sixth voltage threshold; when the third time length is greater than the third time length threshold, or when the fourth time length is greater than the fourth time length threshold, obtaining the second voltage, wherein the fourth time length is the total time length of the auxiliary relay startup.

[0062] In the above optional embodiment, after obtaining the voltage change value of the second voltage (i.e., the second change value), it is compared with the sixth voltage threshold. When it is determined that the second change value is not greater than the sixth voltage threshold, timing is started and the duration is counted to obtain a third duration. Then, it is determined that when the duration of the timing period (i.e., the third duration, that is, the duration of voltage stability, it should be noted that the third duration can be multiple steps, equivalent to multiple debounces) is greater than the third duration threshold, or when the duration since the main relay is closed (i.e., the fourth duration) is greater than the fourth duration threshold, the calculated insulation detection voltage value is obtained (i.e., the voltage values ​​UposwithR and UnegwithR used to obtain the stabilized insulation resistance).

[0063] It should be noted that, in practice, in order to prevent the voltage from being unstable, the third voltage can be obtained by judging according to the longest time after closing the auxiliary relay (for example, after 10 seconds, the time can be calibrated).

[0064] Figure 3 FIG. 1 is a flow chart of an unbalanced bridge insulation detection process and a control strategy according to an embodiment of the present invention. Figure 3 As shown, the BMS first initializes the low-voltage circuit to determine whether there is an insulation test request. If there is no insulation test request, the insulation test relay does not operate. Otherwise, if there is an insulation test request, the normal insulation test process begins. The following details the steps for determining the insulation test resistance.

[0065] Step 1: Close the insulation detection main relay and start timing. Delay the calculation of the positive-to-negative voltage ratio (including the positive-to-negative ratio and the negative-to-positive ratio). Determine whether these two ratios exceed a certain value. If so, high voltage is prohibited; otherwise, high voltage is permitted. This control strategy ensures rapid diagnosis of insulation faults before high voltage is applied, speeding up power-up initialization. If the battery is already at high voltage and the fault is detected, control the battery to reduce high voltage.

[0066] Step 2: After closing the main insulation test relay, the insulation test voltage begins to be measured synchronously. The change in the insulation test voltage between the current step and the previous step is calculated in real time. If the change is less than a certain value, the timing flag is set. If the duration exceeds a certain value, the insulation test voltage has stabilized. Otherwise, if the change is large, the flag will not be set, or if the flag is set but the duration is too short, the flag will be cleared. In either case, the insulation test voltage has not reached a stable state. Once the insulation test voltage reaches a stable state or the insulation test positive relay closure time reaches the maximum value, the voltage values ​​Upos and Uneg used for insulation resistance calculation can be obtained and latched. Otherwise, if the insulation test voltage is unstable and the insulation test main relay closure time has not reached the maximum value, the voltage value will not be obtained.

[0067] Step 3: After obtaining the voltage values ​​Upos and Uneg, determine whether to close the insulation detection positive or insulation detection negative relay and start timing.

[0068] Step 4: Similarly, the change in the insulation detection voltage between the current step and the previous step is calculated in real time. The control strategy is similar to that in step 2. The stabilized voltage values ​​UposwithR and UnegwithR used to calculate the insulation resistance are obtained and latched.

[0069] Step 5: Based on the obtained voltage values ​​Upos, Uneg, UposwithR, and UnegwithR, the insulation resistance between the positive and negative electrodes of the power battery and the vehicle body shell can be calculated by using the simultaneous equations.

[0070] Step 6: Control all insulation detection relays to disconnect, and then proceed to the next insulation detection process.

[0071] As can be seen from the above, the method provided by the embodiments of the present invention provides a method that adapts to different external and vehicle environments, automatically identifies voltage stability, and automatically adjusts the detection cycle, thereby rapidly detecting insulation resistance. This solution ensures the fastest insulation testing and diagnosis of insulation faults in any battery state. By directly diagnosing the ratio of the main positive and negative voltages before applying high voltage, reporting a fault and performing downgrade processing, this approach is more timely and time-efficient than waiting for the voltage to stabilize during the insulation testing process before calculating the insulation resistance. The insulation testing process acquires the insulation test voltage based on the voltage stability state and determines when the duration exceeds a certain value. If the voltage remains unstable, the maximum time since the insulation detection relay was closed is determined, and the voltage is directly obtained for insulation resistance calculation. Furthermore, the method provided by the embodiments of the present invention not only ensures the rapid diagnosis of insulation faults before applying high voltage to the battery, thereby preventing the application of high voltage to the battery, thus ensuring personal safety, but also prevents the problem of applying high voltage first, then determining an insulation fault, and then reducing high voltage due to the lack of early diagnosis of insulation faults. It also ensures that the BMS achieves the fastest insulation testing speed and the most accurate insulation resistance calculation value in any state.

[0072] Example 2

[0073] According to one aspect of an embodiment of the present invention, a device for determining insulation resistance is further provided. Figure 4 Schematic diagram of an insulation resistance determination device according to an embodiment of the present invention. Figure 4 As shown, it includes: a first acquisition module 41, a second acquisition module 43, a third acquisition module 45, and a determination module 47. The device for determining insulation resistance is described in detail below.

[0074] A first acquisition module 41 is configured to respond to an insulation detection request and acquire a first voltage of the main relay, wherein the first voltage is a dynamic voltage value after the main relay is closed;

[0075] a second acquisition module 43 configured to acquire a second voltage when it is determined that the voltage difference between the first voltage and the historical voltage satisfies a first preset condition, wherein the second voltage is a voltage value acquired when the first voltage reaches a first voltage threshold, and the historical voltage is an average voltage value within a previous statistical period;

[0076] a third acquisition module 45, configured to trigger the auxiliary relay to close after acquiring the second voltage, and acquire a third voltage when a voltage difference between the second voltage and a second voltage threshold satisfies a second preset condition, wherein the third voltage is a voltage value acquired when the second voltage satisfies the third voltage threshold;

[0077] The determination module 47 is configured to determine the insulation resistance of the insulation resistor based on the second voltage and the third voltage.

[0078] It should be noted here that the above-mentioned first acquisition module 41, second acquisition module 43, third acquisition module 45, and determination module 47 correspond to steps S102 to S108 in Example 1, and the instances and application scenarios implemented by the multiple modules and the corresponding steps are the same, but are not limited to the contents disclosed in the above-mentioned Example 1.

[0079] As can be seen from the above, in the embodiment of the present invention, first, the first acquisition module 41 responds to the insulation detection request and obtains the first voltage of the main relay, wherein the first voltage is the dynamic voltage value after the main relay is closed; then, the second acquisition module 43 can be used to obtain the second voltage when it is determined that the voltage difference between the first voltage and the historical voltage meets the first preset condition, wherein the second voltage is the voltage value obtained when the first voltage reaches the first voltage threshold, and the historical voltage is the average voltage value in the previous statistical period; then, the third acquisition module 45 can be used to trigger the auxiliary relay to close after obtaining the second voltage, and when the voltage difference between the second voltage and the second voltage threshold meets the second preset condition, the third voltage is obtained, wherein the third voltage is the voltage value obtained when the second voltage meets the third voltage threshold; finally, the insulation resistance can be determined based on the second and third voltages by the determination module 47. The insulation resistance determination device provided by the embodiment of the present invention achieves the purpose of measuring the insulation resistance value when the system relay voltage is stable, thereby achieving the technical effect of improving the accuracy of insulation resistance detection, thereby solving the technical problem that the means for collecting insulation resistance values ​​in the related art do not fully consider environmental factors, resulting in inaccurate detection results.

[0080] Optionally, the device also includes: a first acquisition unit, used to obtain the voltage ratio of the positive terminal voltage to the negative terminal voltage of the main relay in response to the insulation detection request and before obtaining the first voltage of the main relay; a second acquisition unit, used to obtain the comparison result of the voltage ratio and the fourth voltage threshold; a prohibition unit, used to prohibit the main relay from performing upper high voltage and lower high voltage operations when the comparison result is that the voltage ratio is greater than the fourth voltage threshold; and a permission unit, used to allow the main relay to perform upper high voltage operation when the comparison result is that the voltage ratio is not greater than the fourth voltage threshold.

[0081] Optionally, the second acquisition module includes: a third acquisition unit, used to obtain a first change value between the first voltage and the historical voltage; a fourth acquisition unit, used to compare the first change value with the fifth voltage threshold, and obtain a first duration when it is determined that the first change value is not greater than the fifth voltage threshold, wherein the first duration is the duration that starts when it is determined that the first change value is not greater than the fifth voltage threshold; a fifth acquisition unit, used to obtain the second voltage when the first duration is greater than the first duration threshold, or when the second duration is greater than the second duration threshold, wherein the second duration is the total duration of the main relay startup.

[0082] Optionally, the third acquisition module includes: a sixth acquisition unit, used to obtain the second change value of the second voltage, wherein the second change value is the absolute value of the difference between the dynamic voltage maximum and minimum values ​​of the second voltage; a comparison unit, used to compare the second change value with the sixth voltage threshold; a seventh acquisition unit, used to obtain the third duration when it is determined that the second change value is not greater than the sixth voltage threshold, wherein the third duration is the duration that starts when it is determined that the second change value is not greater than the sixth voltage threshold; an eighth acquisition unit, used to obtain the second voltage when the third duration is greater than the third duration threshold, or when the fourth duration is greater than the fourth duration threshold, wherein the fourth duration is the total duration of the auxiliary relay startup.

[0083] Example 3

[0084] According to one aspect of an embodiment of the present invention, a computer-readable storage medium is further provided, the computer-readable storage medium including a stored program, wherein when the program is run, the device where the computer-readable storage medium is located is controlled to execute any one of the methods for determining insulation resistance.

[0085] Example 4

[0086] According to one aspect of an embodiment of the present invention, a processor is further provided, the processor being configured to run a program, wherein when the program is run, any one of the methods for determining insulation resistance is executed. The serial numbers of the above embodiments of the present invention are for description only and do not represent the merits or demerits of the embodiments.

[0087] In the above embodiments of the present invention, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0088] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only exemplary. For example, the division of the units can be a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0089] The units described as separate components may or may not be physically separate, and 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 units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0090] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0091] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk, etc. Various media that can store program codes.

[0092] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for determining insulation resistance, characterized in that: include: Responding to an insulation detection request, and acquiring a first voltage of a main relay, wherein the first voltage is a dynamic voltage value after the main relay is closed; When it is determined that the voltage difference between the first voltage and the historical voltage meets the first preset condition, a second voltage of the main relay is obtained, wherein the second voltage is a voltage value obtained when the first voltage reaches a first voltage threshold, and the historical voltage is an average voltage value in the previous statistical period. The first preset condition is met if the voltage difference between the first voltage and the historical voltage is less than a fifth voltage threshold and the duration is greater than a first duration threshold or the total startup duration of the main relay exceeds a second duration threshold; After obtaining the second voltage, triggering the secondary relay to close, and obtaining a third voltage when a voltage difference between the second voltage and a second voltage threshold satisfies a second preset condition, wherein the third voltage is a voltage value obtained when the second voltage satisfies the third voltage threshold, and the third voltage includes a positive terminal measurement voltage and a negative terminal measurement voltage; Determining the insulation resistance of the insulation resistor based on the second voltage and the third voltage includes: a calculation formula for the insulation resistance of the main positive terminal of the insulation resistor is: , The insulation resistance of the main positive terminal of the insulation resistance is represented by the insulation resistance, and the insulation resistance of the main negative terminal of the insulation resistance is calculated as follows: , The main negative terminal insulation resistance representing the insulation resistance; Wherein, obtaining the third voltage includes: obtaining a second change value of the second voltage, wherein the second change value is the absolute value of the difference between the dynamic voltage maximum and minimum values ​​of the second voltage; comparing the second change value with the sixth voltage threshold; upon determining that the second change value is not greater than the sixth voltage threshold, obtaining a third duration, wherein the third duration is the duration that starts when determining that the second change value is not greater than the sixth voltage threshold; when the third duration is greater than the third duration threshold, or when the fourth duration is greater than the fourth duration threshold, obtaining the third voltage, wherein the fourth duration is the total duration of the auxiliary relay startup.

2. The method according to claim 1, characterized in that Before responding to the insulation detection request and acquiring the first voltage of the main relay, the method further includes: Obtaining a voltage ratio between a positive terminal voltage and a negative terminal voltage of the main relay; Obtaining a comparison result between the voltage ratio and a fourth voltage threshold; If the comparison result shows that the voltage ratio is greater than the fourth voltage threshold, prohibiting the main relay from performing the high voltage up and high voltage down operations; If the comparison result shows that the voltage ratio is not greater than the fourth voltage threshold, the main relay is allowed to perform a high-voltage operation.

3. A device for determining insulation resistance, characterized in that: include: A first acquisition module is configured to respond to an insulation detection request and acquire a first voltage of the main relay, wherein the first voltage is a dynamic voltage value after the main relay is closed; a second acquisition module, configured to acquire a second voltage of the main relay when it is determined that a voltage difference between the first voltage and the historical voltage satisfies a first preset condition, wherein the second voltage is a voltage value acquired when the first voltage reaches a first voltage threshold, and the historical voltage is an average voltage value within a previous statistical period, and the first preset condition is satisfied if the voltage difference between the first voltage and the historical voltage is less than a fifth voltage threshold and the duration is greater than a first duration threshold or the total startup duration of the main relay exceeds a second duration threshold; a third acquisition module, configured to trigger the auxiliary relay to close after acquiring the second voltage, and acquire a third voltage when a voltage difference between the second voltage and a second voltage threshold satisfies a second preset condition, wherein the third voltage is a voltage value acquired when the second voltage satisfies the third voltage threshold, and the third voltage includes a positive terminal measurement voltage and a negative terminal measurement voltage; A determination module is configured to determine the insulation resistance of the insulation resistor based on the second voltage and the third voltage, including: a calculation formula for the insulation resistance of the main positive terminal of the insulation resistor is: , The insulation resistance of the main positive terminal of the insulation resistance is represented by the insulation resistance, and the insulation resistance of the main negative terminal of the insulation resistance is calculated as follows: , The main negative terminal insulation resistance representing the insulation resistance; The third acquisition module includes: a sixth acquisition unit, used to obtain a second change value of the second voltage, wherein the second change value is the absolute value of the difference between the dynamic voltage maximum value and the minimum value of the second voltage; a comparison unit, used to compare the second change value with the sixth voltage threshold; a seventh acquisition unit, used to obtain a third duration when it is determined that the second change value is not greater than the sixth voltage threshold, wherein the third duration is the duration that starts when it is determined that the second change value is not greater than the sixth voltage threshold; an eighth acquisition unit, used to obtain the second voltage when the third duration is greater than the third duration threshold, or when the fourth duration is greater than the fourth duration threshold, wherein the fourth duration is the total duration of the auxiliary relay startup.

4. The device according to claim 3, characterized in that The device further comprises: a first acquiring unit, configured to acquire a voltage ratio between a positive terminal voltage and a negative terminal voltage of the main relay in response to an insulation detection request and before acquiring the first voltage of the main relay; a second acquiring unit, configured to acquire a comparison result between the voltage ratio and a fourth voltage threshold; a prohibition unit, configured to prohibit the main relay from performing an upper high voltage operation and a lower high voltage operation if the comparison result shows that the voltage ratio is greater than the fourth voltage threshold; The permission unit is configured to permit the main relay to perform a high-voltage operation if the comparison result shows that the voltage ratio is not greater than the fourth voltage threshold.

5. A computer-readable storage medium, characterized in that The computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the method for determining insulation resistance according to claim 1 or 2.

6. A processor, characterized in that: The processor is configured to run a program, wherein the method for determining insulation resistance according to claim 1 or 2 is executed when the program is run.

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